Ski-Doo Snowmobiles Forum banner
281 - 300 of 314 Posts

·
Premium Member
Joined
·
27,934 Posts
Reloading a Map (Calibration file) with BUDS version 3.8.2.1

With BUDS version 3.8.2.1 go to the ECM menu and select Update. It will give a list as shown in the second picture. For this ECM that I was reloading, it already had the Seal Level map (S.L.). This is normal since BUDS does not provide the option to reload the same map. So pick another map - I chose the 07 mid map - do the update and go through the same process to reload the 07 Sea Map.

It is not a long nor difficult procedure and no programing nor changes are needed.

Keep the ECM awake!

Make sure to have a positive 12Vdc feed to the ECM wake-up circuit through the single White/Violet wire plug at the VRR (Voltage Regulator Rectifier). I guess that I should provide pictures, but I am not there yet. You probably know of the Red/White wire on top of the battery tray with the 30A fuse, this one needs a positive 12Vdc feed. The Red/White powers the circuits, and the White/Violet keeps the ECM awake. Ground is chassis, so that's simple.

For the positive setup, I used a 14 gauge red wire to run from an external battery to a toggle switch, and two wires from the toggle switch to the Red/White and White/Violet. In other words I am toggling both positive wires.

Avoid Accidental shorts to ground!

Be sure to protect any of these positive connections from chassis ground. If not and you accidentally cause a short, say good buy to your voltage regulator and possibly the MPI. I never burnt an MPI yet, but I have burnt a VRR and the Posi-Flow pump due to accidental shorts. For this reason always make the ground connection last.

This goes for boosting the battery which should be avoided, which is no joke. One thing that I learned by following the 600 and 1000 SDI on DooTalk is there are accidental shorts that happen. Having done this myself in 2013, it gave me the heads up to ask the owners if this happened when the VRR fried, and it did, or at least there was a boost involved. If you want to look it up, It is somewhere in the sea of threads between the Mach Z and REV forum somewhere in between 2013 and 2015.

On the REV forum there was one case that a 600 SDI owner could not get his dealer to connect BUDS to the ECM. When he posted the dealer had ordered a new ECM and VRR, it was suggested to cancel the order and he ended traveling from Oregon to Colorado to get his 600 SDI serviced by an SDI connoisseur using a CanDoo. When the owner asked why a VRR was needed, the tech said just because when a new ECM is needed it is standard practice to also order a new VRR.

I hope that you are beginning to see the big picture with too many VRRs that have been fried from accidental shorts from the owners and dealers. A mistake can be made when replacing a battery or connecting the BUDS Power Adapter. However it happens, it happens. We may have been led to believe the 1000 SDI was unique in its problems, but it is all encompassing the SDI series. They are all fantastic engines, and it becomes important to know how to avoid their pitfalls.

TPS and Offset Angle

As mentioned, this is not necessary as it keeps the existing TPS and Timing Offset. Of course if the TPS or offset was not right in the first pace, then obviously it needs to be done.

When performing a TPS reset, keep in mind the TPS needs to be backed to the zero stop position which is a part of the carbon track that is never used other than for the reset. This is the reason that the shop manual instructs to flick the throttle mechanism several times to clear this track.

The Offset Angle is to set the timing for the Ignition and Fuel Injection. I assume most sleds will work fine with the default 0.7 deg. However there are two cases known to me with the default timing was completely out of wack. One was a 1000 SDI with several degrees advance, and the other was known this past season with several degrees retard. In the case of the 850 it was a slouch until the owner turned up the advance, and in the case of the 1000 SDI with a mid map it showed to be the strongest stock 1000 SDI ever seen.

BRP hand written Racing handbook for the 1000 SDI

There is such a thing as a BRP hand written Race manual for the 1000 SDI. The most important part that I remember is it detonated over 8 deg @ wot. Of note, the stock one with mid map was a lot higher. Keep in the mind that both the 850 and 1000 had this advance from the magneto flywheel. It is supposed to work the same as the Offset Angle, but I did find one elusive thread from a member who vowed that his RT race sled did considerably better with an offset timing key than with the Offset Angle. There is no way for me to validate this without trying it for myself, so I will leave you with the same question mark I had.

Break-In Chip

It has been suggested that updating the map resets the Break-In chip, but I was never able to verify this. All that I can tell you at this point is my 1000 SDI showed roughly 28 deg advance which I seem to remember out of break-in being around 32 deg. I haven't done this in years, but I remember figuring it out by taking the spec in the 2005 Shop Manual for BTDC which is 7.87 mm (0.3098 in).

In other words I am not sure, but you can figure it out if you care to.

Air/Fuel Ratio

After performing an Update, the A/F held remarkably steady @ ~14.4 in the 5500-6500 range, and jumped to ~13.4 when crossing 6,500 rpm where the high speed injectors kick in. There was a variance at wot between 11.6 and 12.2 , but it seem to depend in large part on the ambient temperature, and obviously trail conditions. In the archives you can find owners like Onapull who remarked the engine was remarkably strong at certain certain temperatures. When I took the picture of my sled for the C&T competition, it was about 15 mins after the reload and it pulled like it had never done at 12.2 . For this reason I never had trouble believing Onapull.

Of note with the A/F, my sled with stock reeds had a steady reading as opposed to two sleds with Boyesen reeds that I compared to. There are many things to consider when comparing a/f, but reeds are one of them.

The reason that I wanted to reload the map was that I kept reading these sleds pulled like a freight train and mine never did. After installing a wideband I saw wot @ 10.9 to 11.2 which did not look right to me for a FI sled. The 5500-6000 range was in the 15s and 16s which also didn't look right, although there was no reference to any of this on the forum.

BRP Dealers will likely not do this procedure

This was the elusive procedure that I once found on this forum. It may have been mentioned more than once, but I found it one time and I have lost the link to the post. Of note, this is the procedure that Dealers do not want to do - unless you are lucky - and will give the excuse that a special code or authorization is needed from BRP. I don't have the full list of excuses off the top of my head, but I heard most of them straight for the dealers, including it takes a special version of BUDS, and it can take 15 min or 2 hours.

One thing is for certain, buying this sled and relying on BRP dealers for service is not a good combination. The number of owners who have literally been laughed at by folks in the service or parts department is surreal. They simply do not want anything to do with this engine. In my ways I agree with them. As a real example that happened from a dealer and also owner service, when servicing the eRAVE the screws were not installed properly and backed out. It both cases it happened with skilled people. The advantage of doing your own work is having the time to thing it though, which also becomes a disadvantage if you work out of fear. It is a difficult balance.

Now if you find a BRP tech who is willing to work on you sled as a side line, then you may have something good. Don't let me give the wrong impression, the techs are experienced and very good at what they do. I will put a BRP tech over me any day, but I do have the advantage of time and focus on particular sleds. I have been left with far more questions than I would like, so hopefully you can get something out this crazy experience.

By the way I got this done at my local dealer with only a BUDS dealer license. I had to go under the premise of a TPS reset to then have a BUDS report printed and have him log onto DooTalk to show the Mach Z forum FAQ had the calibration parts numbers to see what map we had. Lucky for me the tech was impressed enough to consider we might be able to update the map without some elusive BRP code. Eight years later you get to see the screenshots of what I saw with a Dealer license. This time I am doing the update with a Megatec license.

If you skipped through to this section, there is more about deal work in the above paragraph <Avoid Accidental shorts to ground!>

Screenshots of the Update

The first screenshot is showing the Update option greyed-out. This is what it looks like when the ECM is bricked from using the clear option in BUDS version 3.5.0 without the power adapter, so avoid using this option unless you know enough BUDS....

Update Calibration file 1.jpg

Note in the screenshot below I do not have access to the 2007 Sea Map because it is already installed in ECM. I need to load any of the available maps to later choose the 2007 Sea Map again to complete the reload. In other words I cannot reload the same one, so I load a different one and load the same one back later.

Update Calibration file 10 Selecting Mid Map.jpg

Update Calibration file 3.jpg

Update Calibration file 4.jpg

There are a few screens missing here that passed by too quick for a screenshot, but an important one showed that it was Deleting Flash Data. Back in 2013 when I have this done by my by my local dealer, there were 255 errors in the Flash Data that I suspect was causing trouble in my previous load. I had no such error this time around and only did reload for the screenshots.

Update Calibration file 5.jpg

Update Calibration file 6.jpg

Once the update has completed, the message below will appear. Remove the DESS key and this message will eventually disappear, and once it does re-insert the key, wait for the large Read Data button at the top left of the screen to change from greyed-out to bold and press it to have BUDS re-read the new ECM load.

I have done it with-out the re-read to then reload the Sea Level map, but for the next load it caused the message from the picture below to not disappear on its own after removing the DESS key and I had to shut the ECM manually with my toggle switch. I mention this is case you forget and has you pause and worry. Count the number of seconds it takes for the message to disappear the first time, and this will give you a hint for how long to wait before giving up and manually switching off the ECM.

Update Calibration file 7.jpg
 

Attachments

·
Premium Member
Joined
·
27,934 Posts
1000 SDI Calibration Maps

Below is a picture the different 2006/2007 maps. Of note BRP has excluded the two first 2005 maps from the updated map file <219 700 745.fc> . This list can be seen in BUDS by going to the Tools menu and selecting Update Database. This is also the menu to load the file for the 2005 maps. The 2005 map file has been circulated among the DooTalk members and beyond, so it should not be difficult to find. I was told that it required an older version of BUDS, but I don't remember which one. I suspect 3.5.0 will work, but I have never tried to load it so I cannot say for sure. This was a map that did best for top speed which I not even interested in. You can read all about the map from BlueMax in the archives. From what I have understood it is no longer needed, but if you have an interest in this map then at least you have an idea on how to go about loading it. If ever I find it from my own emails, I will make it available on the same site that you can get most of the bulletins.

A mention for the bulletins, between what BlueMax has already provided in the FAQ and what is in this thread, there is not much left to find. BlueMax has already posted multiple times the content that I have gathered in this thread, so what I am posting are some of the finer details on the simpler stuff.

Of note in the list of calibration maps shown in the picture below. The FAQ is showing the first 2006 map as 420-664-713 while the picture below that I took from BUDS shows 420-665-761 . I figure it is a minor error since who really cares about the first 2006 map which was problematic. It was quickly superseded by the second 2006 map (rework) to help fight against the plugs fouling on cold starts. With what we know today, plug fouling is not even an issue with any map. The 2007 maps were to cure the problems with eRAVE for those who throttle pump. Throttle pumping is more common with off-trail sleds, and trail sleds to get in/out of the garage and trailer. Bill Cudney once provided an explanation of this on this forum. Since I don't throttle pump, my first hand experience is with finding that I could foul a plug on command using throttle pumping. I was just trying to find the elusive electrical surge that I had read about and found it through trial & error. I found both the surge and plug fouling with the same throttle action.

Calibration Files.jpg

2005 Maps

I never ran these maps so what I know is limited at best. What I do know is the EGTM is disabled (Exhaust Gas Temperature in the Muffler), and there was an open question on the use or effectiveness of the knock sensor. I honestly do not know if this had to do with what I mentioned in an earlier post for Knock Protection or perhaps knock sensitivity. I mention it only if you have an interest in this map and wish to look it up in the archives.

Performance mods made to the ECM

This is the fun stuff. It is another of those things that I have no first hand experience with, but I do have some inside knowledge, so take it for what it is worth. There are multiple things that can be done to the ECM for racing, namely the speed at which the eRAVE open and the functioning of the APS. Both are programming changes in the ECM. There has been a picture posted on this forum of a Montreal Mach with two external wires from the ECM which I suspect were for the APS, but this I do not know. All that I know for the APS is that it affects the timing and fuel, and maybe the eRAVE opening but I do not know. BlueMax wrote about the APS which can be found in the archives.

Next time you have the chance to rip down a long field or a lake, do multiple acceleration passes and take note of the intake/exhaust note when the rpm crosses 6,500 rpm. The 600 SDI with the 2004 map does the same thing at the same rpm. It feels like a boost. For the shorter 500 foot races on tar this needs to happen sooner, hence the change in programming for the ECM.

BlueMax, Andy670ho, Standingman have posted about the take-off with a stock ECM, so in my opinion this isn't an issue. In later years RX7MachZ and Crazy Bill have also shown what was possible with the stock ECM, so I figure for us common owners it not even worth following the modded ECM. Even to win a race or competing with the 850s and the new 2022 turbo Mach Z, there are so many things that can and need to be done to show the true power of the 1000 SDI.

As a perfect example, if a 1000 SDI shows 120 psi of compression, there is no amount of performance mods that will bring it to the level of a well running stock Mach Z. It may still overtake a 600 on a lake, but in a short race it will be beat by a well running 600. Sorting through the mess to get the engines running like it is meant to is precisely what RX7MachZ has been doing in the past few years to his growing fleet of Mach Z.

I got lucky and never seen these low compression numbers until two years ago with an engine that RX7MachZ was rebuilding with a honed cylinders and new OEM pistons/rings that was showing 115/145, then this past winter with a local Mach Z showing 120 psi. I still need to measure the low 120 psi with my own gauge, but that is exceptionally low for around 200 feet elevation.

Competing with the new 2022 boosted Mach Z

2022 will be an interesting year. The weak 1000s will obviously take a beating and you can be sure to hear about those on the forum. I predict the ones working well will have a challenge just to compete. If you have ever seen a well setup triple 809 Mach Z compete against a 1000 SDI Mach Z, I suspect that you are familiar with the challenge. There is Power from the engine, Transfer of power to the track, and Traction. There are current 1000 SDI Mach Z that compete with higher powered turbo four strokes in the lower to mid 200 Hp range, but they are few and far in between. With less power, say 200 Hp, to compete with 240 Hp there needs to be an advantage with the later two, power to track and traction. Power to the track is everything from minimizing the losses to track, to the acceleration from the clutches. It sounds easy until you need to run the same track over and over. RX7MachZ and I share about the same amount of tolerance before we get bored with this broken record type of deal. It is fun in the beginning, but in the past we got bored after 10 to 20 runs and stop caring.

Tricking the APS, and tweaking the A/F using Byte 3 in the Advance tab may do some good. Both RX7MachZ and I run Widebands and have access to this A/F tweak, but putting a $3K engine at risk is only interesting when others do it in the racing venues. If you saw the plugs that I posted from the mid map they were a nice off white, but not inspiring for trail reliability when having to cruise in the midrange when the EGT rises into the lower 1300s just before the exhaust valves open. By the way they open at 6,500 rpm only at Wide Open Throttle. When cruising they open a lot higher.

This reminds me that adjusting the Fuel Offset is how I suspect BRP tweaked the performance ECM to run learner. Keep in mind that running leaner also means the timing cannot be advanced as much.

I will look into a few performance mods with RX7MachZ that I have referred to in this thread, but I have lost a certain amount of enthusiasm on this front in just trying to figure out the details. In other words don't count on me to show the possibilities. I suspect that RX7MachZ and I will be doing more with the 414 setup and taking another try at the Magic Clutch which has the elusive mid weight BRP arms. As the term implies, the mid weight arms are the ones that weigh in between the ones for the 800s and the 1000s. I think it is self evident which one have the best chance for highest performance. At least RX7MachZ has the traction covered on his primary Mach Z 1000 and he are not starting from scratch. Perhaps his 2022 Mach Z will invigorate a lost passion.

As a hint on clutching, in any clutch setup on the 1000 SDI needs the spring in the secondary to be either up to snuff, or or a little bit over to take the abuse. That may be good for another information dump ;)
 

Attachments

·
Premium Member
Joined
·
27,934 Posts
Discussion Starter · #283 ·
Exhaust Cross-Flow Contamination

This is a something I picked-up from a string of SDI failures of 600s and 1000s which I have yet to see with carbs. For example the mag side plug looks obviously leaner than the pto, but the pto failed and the plug looks like it got hotter. Flow check the injectors and the mag side was clearly running leaner.

I searched it and found nothing, then did wide search across the aftermarket and came-up empty. So if you haven't heard of it, well neither have I.

Several years back someone on DooTalk mentioned the Mazda SkyActiv G and X on some technology thread. While viewing the videos the improvement to the exhaust system with a 4-2-1 header caught my attention. In the first two pictures it explains the purpose is to reduce the amount of residual gases in the cylinders. Pictures three, four and five depict the cross-flow contamination of exhaust gases in a typical 4-1 header. Picture six shows the intended flow of exhaust gases from a 4 into 2 into 1 header (4-2-1).

This is the only explanation I have been able to find for what I believe happens when a twin two stroke is heavily unbalanced between the mag and pto side that share a tuned pipe with a short run y-pipe. So take it for what it is worth

These were engines with relatively close compression between pto and mag, and with enough mileage and piston clearance that it wouldn't cause an immediate lean seize it if was it little too lean. The difference in injector flow rate was substantial, not 5-10%, but closer to 15-25+% due to storage issues, so it was not a minor imbalance. Between these occurrences and seeing them survive red hot mufflers is how I learned the SDI had a surprising amount of tolerance as long as the fuel was good (RVP and Octane). The fuel quality goes in hand with the knock protection strategy that I mentioned in an earlier post.

SKYACTIV-G Petrol Engine A Technical Explanation by one of Mazda's Engineers

SKYACTIV-G 2.5 T | Dynamic Pressure Turbo | Mazda Canada

SkyActiv-G  4-2-1 pipes - 1.jpg

SkyActiv-G  4-2-1 pipes - 2.jpg

SkyActiv-G  4-2-1 pipes - 3.jpg

SkyActiv-G  4-2-1 pipes - 4.jpg

SkyActiv-G  4-2-1 pipes - 5.jpg

SkyActiv-G  4-2-1 pipes - 6.jpg
 

Attachments

·
Premium Member
Joined
·
27,934 Posts
Exponential Functions

After a few years I finally figured out how to solve for R the equation to find the common ratio between two points.

r ^ 4 = 1.16851

r ^ 4 = the ratio of 1.16851

The answer is:
r = 10 ^ (Log(1.1818) / 4)

Lots of math stuff on YouTube, but trying to figure this seemingly easy equation was always met with examples that were easy to simplify and did not apply to my task.

I had used Khan Academy to figure Exponential Functions which was good enough to work out what was needed for the Fuel vs Oil consumption. However, this particular problem to figure R was not explained, so I manged to work it manually on a calculator by starting with a number like 1.01 until I would reach the answer. It only took 5 to 10 min, but it got annoying fast.

A few nights ago while I was working through different Exponential Functions that I had worked on in the past as a draft and put off for later, I decided to give another shot to solving the riddle of the R. I tried lessons from a few other YouTubers and could not relate, so I went back to Khan Academy and landed on the following course.

Solving exponential equation | Exponential and logarithmic functions | Algebra II | Khan Academy

It led me to a Log base 4 of 1.16851 that equaled 4 which made no sense.

Log[r] (r^4) = Log[r] (1.16851)
4 = Log[4] (1.16851)
[It did not work]

Here is what I eventually worked from the video. Since I knew the answer, I figured why not substitute the known answer with a unknown.

4 x a = Log (1.16851)
a = Log (1.16851) / 4
a = 0.0676 / 4
a = 0.0169
[It still do not work]

It was just enough to realize that I only had three numbers to work with, the 4, the Log of (1.0397) and the Log of (1.16851). At this point it only took a few minutes to figure the different combinations until I found the following below that did work:

Log (1.16851) / Log (1.0397) = 4
0.0676 / 0.0169 = 4

The above was THE break through with something that finally made sense. From there I watched the video again and picked-up something about the Log function being the inverse of the exponential function, and to apply the useful properties of exponents. I found it elusive, but there was also something about the default Log function using a base 10 which had me question the calculator having an option for 10 of X that may have something to do with the inverse.

Since the Log (1.0397) was the unknown, I figured that I had only two numbers left to work with, the Log (1.16851) and the number 4. So I took the Log (1.16851) and divided by 4, then took the risk of applying 10 of X which resulted to 1.0397 , the number I had been looking to reach.

By the way, I did give the answer at the very beginning, so don't blame me if you read through this whole post :) But seriously, the above was only for my own notes to remember how I reached this point.

It is useless without a table or graph, but I am getting there, slowly. Keep in mind I that I worked through most of these things years ago trying to figure if there was any value. It was obvious with the Fuel versus Oil consumption, but it is not so clear with other things. The relationship is not clear until different types of functions are used see how it works.

I made this particular post to merely to show the math for anyone who wishes to duplicate the effort. What is shown including the colors coded numbers is precisely what I use to formulate other Exponential Equations. Without the colors and headings, it turns into bunch of wild numbers that become incomprehensible. It may not look it, but you have more than enough to work it out.

Next up is to see if these exponential functions can provide anything useful.
 

·
Premium Member
Joined
·
27,934 Posts
Discussion Starter · #285 ·
Using Exponential Functions

Bikeman's dyno testing of the turbo 850 E-TEC had me wonder if there is an exponential factor to the Boost vs Power. I used it to compare with dyno numbers for a Turbo 995 which used the 1000 SDI converted to carbs. They are two different engines and tunes, so I just wanted a quick look.

Boost vs Hp/1000cc

From the numbers in the table below, the relationship is clearly exponential. Since I had Boost vs Hp numbers for the Turbo 995 (1000 SDI converted to carbs), I needed to convert to show HP per 1000cc which is shows as the second table.

Having only two points for the 1000 at very high boost of 20 and 25 psi, I was surprised to see the Hp/1000cc for 1 psi was nearly the same between the 1000 @ 211 Hp/1000cc and the 850 E-TEC @ 209 Hp/1000cc.

At this point I am merely using two engines that I have numbers to find an exponential function and compare. The benefit is having a tool to look at things differently than only linear changes.

Bikeman Tech Tues | Ski-Doo 850 E-Tec Turbo

Turbo 850 E-TEC
171 Hp @ 0.5 psi boost @ 91 octane
178 Hp @ 1 psi boost @ 91 octane
188 Hp @ 2 psi boost @ 91 octane
198 Hp @ 3.5 psi boost @ 93 octane
208 Hp @ 5 psi boost @ 95 octane

x (psi) | f(x) Hp/1000cc
----------------------------------
1 psi | 209 Hp/1000cc
2 psi | 221 Hp/1000cc
3.5 psi | 233 Hp/1000cc
5 psi | 245 Hp/1000cc

Exponential Function for Hp

f(x psi) = a * r ^ x
f(1 psi) = a * r ^ x = 209 Hp
f(5 psi) = a * r ^ x = 245 Hp

Find the Common Ratio between two points:

f(5 psi) 245 Hp/1000cc 1.17225 a * r ^ 5 psi
----------- = --------------------- = ------------- = ---------------- = r ^ (5 psi - 1 psi) = r ^ 4
f(1 psi) 209 Hp/1000cc 1 a * r ^ 1 psi

The equation shows that:
r ^ 4 = the ratio of 1.17225

Use logarithm to solve for r:
r = 10 ^ (Log(1.17225) / 4)
r = 1.04053

Solve for a
f(x) = a * r ^ x
f(5) = a * 1.04053 ^ 5
f(5) = a * 1.21975

Since the table shows that f(5) = 245 Hp
a * 1.21975 = 245 Hp
a = 245 Hp / 1.21975
a = 200.86032

The function can now be built with having the values for a, r and x:

Exponential Function
f(x) = a * r ^ x
f(5) = 200.86032 * 1.04053 ^ 5

Equations for a spreadsheet
Hp/1000cc = 200.86032 * 1.04053 ^ psi

Twin 1000 (Rotax Type 995) running carbs
350 Hp/1000 cc @ 20 psi boost
400 Hp/1000 cc @ 25 psi boost

x = Boost
f(x) = Hp/1000cc

x (psi) | f(x) Hp/1000cc
---------------------------------------
20 psi | 350 Hp/1000cc
25 psi | 400 Hp/1000cc

Exponential Function for Hp/1000cc
f(x) = a * r ^ x
f(5) = 205.163977 * 1.027066 ^ 5

Equations for a spreadsheet
Hp/1000cc = 205.163977 * 1.027066 ^ psi
 

·
Premium Member
Joined
·
27,934 Posts
Tip Weight versus Hp

Without a dyno the only way that I know to estimate an increase or decrease in Horsepower is with Tip Weight. There are too many variables to estimate the actual power and this is definitely not scientific. So take it for what it is worth which is providing the means to work with Exponential Functions.

Is the relationship between Hp and Tip Weight linear or exponential? Having the tools to do both shows that either way comes out close enough to 4.77 Hp for each additional gram of Tip Weight.

The caveat is this is only good for a stock clutch setup (primary and secondary) with excellent traction, 29/49 gearing, 121x15x1.25 track and ~7900 rpm on the stock tachometer. In this form it requires roughly 203 Hp to pull 20g of Tip Weight. It is worth repeating there is no scientific tests behind these numbers, so take it for what it is worth. The idea is only to show there is indeed a relationship between the two.

The rpm shown on the stock tach doesn't really matter for this. The reason is the Tip Weight is in relation to the rpm that proves to have the best power. So the 20g @ ~203Hp is at best power rpm. I think the TD gauge (Turbo Dynamics) for $300 CND is the next step to figure this. I hope to see this next year under the xmas tree.

A good reason to look into this relationship is to consider what the RT version of the Mach Z is capable of versus the 2022 Mach Z Turbo 900R. Considering stock clutching, my guess is the engine will need to pull a lot more then the typical 16-17g. I am guessing that it will take at least 18g to match peak power, and probably 19+g to compete against all of the other advantages.

I think 2022 will prove to be a interesting season for the Mach Z.

x (Tip Weight) | f(x) Hp
----------------------------------
16g | 165 Hp
20g | 203 Hp

Exponential Function for Hp

f(x) = a * r ^ x
f(16g) = a * r ^ x = 165 Hp
f(20g) = a * r ^ x = 203 Hp

Find the Common Ratio between two points:

f(20g) 203 Hp 1.23 a * r ^ 20g
----------- = ------------- = ---------- = ---------------- = r ^ (20g - 16g) = r ^ 4
f(16g) 165 Hp 1 a * r ^ 16g

The equation shows that:
r ^ 4 = the ratio of 1.23

Use logarithm to solve for r:
r = 10 ^ (Log(1.23) / 4)
r = 1.0531

Solve for a
f(x) = a * r ^ x
f(20g) = a * 1.0531 ^ 20
f(20g) = a * 2.8144

Since the table shows that f(20) = 203 Hp
a * 2.8144 = 203 Hp
a = 203 Hp / 2.8144
a = 72.129

The function can now be built with having the values for a, r and x:

Exponential Function
f(x) = a * r ^ x
f(20) = 72.129 * 1.0531 ^ 20

Equations for a spreadsheet
Hp = 72.129 * 1.0531 ^ Tip Weight
 

·
Premium Member
Joined
·
27,934 Posts
Simplifying the Exponential Function for a spreadsheet

Using the same Tip Weight vs Hp table, the function is simplified as shown below. The last portion shows how to simply it further for a spreadsheet. I use open office which is free and open source, but it should work the same with Microsoft Excel.

To make it simpler to build the spreadsheet, I showed the reference to the cells. If you have never done this, then you will probably need ask here or to someone who has worked with spreadsheets. I showed as much as I thought possible so that it takes only hours instead of weeks or months or years like it did for me.

Having gone through this months apart and not quite remembering all the steps, it has led me to spend too many hours trying to sort it out more times than I care to admit. This is the reason that I ended using colors so that I can better follow the process. Math was my strong suit until I hit calculus which drove me nuts because I was not able to work though all the numbers fast enough to compute them all. I refuse to let it set my limits. So if you brain is not math oriented, welcome to the club.

x (Tip Weight) | f(x) Hp
----------------------------------
A1 (16g) | B1 (165 Hp)
A2 (20g) | B2 (203 Hp)

f(x) = a * r ^ x
Ratio = 20g/16g = 1.23
r ^ of ? = 20g - 16g = 4g
r = 10 ^ (LOG(Ratio;Base 10) / 4g) = 1.0531
a = 203Hp / (r ^ 20g) = 72.129

For a spreadsheet:
A5 [r] =10^(LOG(B2/B1;10)/(A2-A1)
A6 [a] = B2/(r^A2)
A7 [f(x)] = A6*A5^A2
 

·
Premium Member
Joined
·
27,934 Posts
Discussion Starter · #288 ·
Clutching from BRP

One of the things that I have often read in the archives is that BRP clutching is not up to par. I beg to differ. BRP and other snowmobile OEMs are at the forefront of the CVT. Contrary to popular belief, they don't just wing it. They use math and test to figure how to clutch a consumer sleds that averages a good recipe for the average rider and adhere to emissions. For example the Mach Z and Renegade was delivered with 434 ramps and clickers set to number 6 which 600s could be beat in short races. Yet they could easily be set to 3 to keep the engine in its power peak for a lot more power. I have found the 434 ramps to be good for regular trail riding, but I have found many left on clicker 6 for the life of the sled.

I believe a key aspect for the crankshaft longevity is lowering the peak rpm to the peak Hp. I was surprised to see how many Mach Z were left clutched to a high 8100 rpm peak. Obviously many of them worked well this way well passed 5,000 miles, but what percentage of wot were they run and how much crank/clutch imbalance did they have? How much oil and what oil? There are too many variables to make a one size fits all assumption. BRP had the dealers lower the clickers and add Tip Weight which was done by the dealers who actually read the bulletins, so that was a pretty good hint. The RT was also released in an era that oil pump adjustment was convoluted as shows in the FAQ, so that only made things worse.

I have come to the conclusion that merely having the sled clutched, oiled, and fueled right, and properly working eRAVE with good voltage is leaps ahead. I have yet to see a properly running Mach Z fail within 5,000 miles. I looked and worked on them, but never found one. What I found from premature failures were sleds that were not working right. Below is the latest fuel quality thread for four and two strokes alike.

dirty fuel filters why?
Started By yammie for now, Apr 16 2021 03:49 PM
 

·
Registered
Joined
·
1,114 Posts
you forget a different ramp with make you add or take pin weight out depending on its profile while leaving the primary finish rate the same..... also you can use the same ramp but use a stiffer finish rate to add pin weight. so that kind of throws your idea for a loop.
 

·
Premium Member
Joined
·
27,934 Posts
Cetaneaddict, are you referring to Tip Weight vs Hp? If so, good observation and thank you for the feedback.
 

·
Premium Member
Joined
·
27,934 Posts
MotoRudyX, I remember the ride when you nearly caught a wild turkey in flight.
 

·
Premium Member
Joined
·
27,934 Posts
Discussion Starter · #294 ·
Either gather dry branches and start a fire with an sos pad across the battery poles for diner, or catch and release :)
 

·
Registered
Joined
·
672 Posts
Either gather dry branches and start a fire with an sos pad across the battery poles for diner, or catch and release :)
I always carry steel wool in my pack. Mainly because I would almost always ride alone. For those who don't know, look it up..
 

·
Premium Member
Joined
·
27,934 Posts
Discussion Starter · #296 ·
Injector Cleaning

Why do this if many RTs have survived thousands of miles without?

I own a 1000 SDI engine with over 7,000 miles that never had the injectors cleaned either, and the engine never failed. The center bearings wore so the engine was replaced with good used one and kept on ticking with the same no injector cleaning. But with this second engine I was able to do pre-season maintenance verification after about 50 miles of on the first ride to examine the plugs at wot. At any rpm below 6,500 rpm the plugs looked fine. Anywhere above 6,500 rpm and the plugs looked abnormally lean. At wot the plugs where white as a ghost, whiter than what I showed in a picture with a mid map. I am doing these checks with dirty/black plugs, so when they go white then all the carbon gets burnt-off the plug. It was scary with the mid map, but still off white in comparison to white with low injector flow.

I need to mention this was not an Air/Fuel reading. I'm not going to take apart a plug to look at the a/f line like in the videos because I use a Wideband to monitor this accurately. Both were running BR8ECS type plugs with one being an Iridium. BR8 runs too hot for my liking, but this is what I had for these tests. I mention the plug type because it affects the reading.

I was not asked to clean the injectors, so I didn't. After a long extended week-end ride the same test showed they were back to normal. The only reason that I could see was the cleaning detergents in the fuel. I know how rider X rides because I followed him for 1,000 miles. I also know how RX7MachZ and MotoRudyX ride, because I followed them too. All three ride nearly the same.

The thing is, any time they feel the need to slow down for whatever reason, such as trailing behind slower riders, the time spent cruising increases dramatically. If they happen to cruise at a particular speed which a set of injectors have trouble flowing, then it will show in how the engine runs. In our pre-covid 2019/2020 ride, I noticed when reaching 6,500 that the engine was making this clicking noise like an unnerving tic-tic-tic. The first time that I noticed it I thought back to a question I had asked rider X back in 2013. How do you know where to run the engine that it self destructs? I was stunned to get just as a direct answer that you could hear it. He could have been referring to any other noise and may or may not ever have have heard the same tic-tic-tic that I did later on. The point is that I tend to cruise at more constant speeds as they do, and I was paying enough attention to the sound of the engine to stay away from what did not sound right.

The 1000 SDI is know to fail at various speeds/rpm, but there are two ranges that I have noticed. There is the 50-60 mph range below 6,500 rpm where only the low speed injectors work. I have seen nor worked on a 1K that died cruising in this range, but I did see and diagnose a 2004 600 SDI that did, which was directly related to the low speed injector flow. The other range is the 6,500+ rpm where the high speed injectors work. That one I saw and diagnosed on the 1K from dirty high speed injectors.

Of note, the 2004 600 SDI ran well for over a decade with no injector cleaning. So for all those owners who never had any trouble with their SDI with no cleaning of the injectors, well I have of those to show the same. A 1000 SDI that went over 7,000 miles, and a 600 SDI that went over 10,000 miles. But it does not make it right. I showed that both had trouble in the beginning of the seasons, the 1K and the 600 SDI that overheated the ring.

You may go a number of years without any engine failure, or you may not. The point is that even if you reach a decade or more without cleaning the injectors, it does not mean the next guy will have the same outcome.

If the first ride is expected to be in mid December, then think of cleaning the injectors a couple of weeks earlier and not four months before. At the beginning of the 2020/2021 season, a member on this forum that I worked with had experienced something I had never seen with the 600 SDI nor 1000 SDI. The injectors that were cleaned at the end of the 2019/2020 season had zero flow in the beginning of the 2020/2021 season. In case that the meaning of zero is not clear, it was not a drop nor any midst, nothing.
 

·
Premium Member
Joined
·
27,934 Posts
Discussion Starter · #297 ·
I always carry steel wool in my pack. Mainly because I would almost always ride alone. For those who don't know, look it up..
Google search

how to start a fire with steel wool

Cool trick for the Mach Z RT unless it is the outcome from being pissed at a failed engine..... lol
 

·
Premium Member
Joined
·
27,934 Posts
Belt Grab with Dual Angle Sheaves

The TRA primary and HPV secondary use sheaves with dual angles. The angles are such that it provides a greater grab on belt when it is near the center of the shaft, and greater shift force as it grows further away. The reasoning is that closer to the shaft center it has a smaller circumference for less surface area to grab onto the belt. As it grows towards the outer rim, it needs less grab and more force to shift up.

As a simple example for the primary, hold your hands parallel to imagine holding a belt tight during the engagement. At say half shift, the belt grab area is so much greater that a higher sheave angle in a V shape is used to push the belt to shift out harder.

The secondary is the same, but in reverse since it begins with the greatest area and falls to the smallest as it approaches full shift. As the belt shifts tighter around the secondary with less circumference, it is has less grab on the belt. Hence the lower angle of the sheaves to compensate for more grab on the belt.

A lower helix angle is also used at higher shift to compensate for less grab by slowing the shift. The belt would slip without slowing down the shift with a shallower helix angle. Hence the stock helix starts with an aggressive steep 44 deg to speed-up the shift after engagement, and ends with a soft/shallow 33 angle to calm it down as it gains speed around a smaller circumference to lower the belt slip. In other words, the lower helix 33 angle nearing full shift provides more time for the secondary to shift out. Between lower angles and spring forces you can figure out what works for top speed with a lower angle. Please do not mistake this for a clutching post. I mention it for too much attention on the primary and too little on the secondary.

From what I have been able to gather, the highest first angle for acceleration should be around 50, and the lowest angle for top speed should be around 30. Again, please do not mistake this for any kind of high performance clutch setup. I am merely showing the relationship in helix angles as a rudimentary cheat sheet. All that I am showing is the side of the secondary helix that rarely gets any attention, and also the spring.

If the secondary spring grows weak, the secondary will shift too fast and generate excess belt slip/heat. This is the reason an new secondary spring is often suggested.

For my own trail riding, I do not foresee going away from stock 44/33 helix with green spring. The lower 44 helix angle also provides better backshift compared to a higher angle. The backshift is needed when letting go of the throttle in corners to allow the belt to go higher in the secondary like downshifting a car after slowing down for a tight turn. When you get into a curve in 5th or 4th gear, you want to downshift to 3rd or 2nd to speed out of it. This is what the backshift does with the clutches. The higher spring rate helps the backshift, so if is week than so is the backshift, and hence starting in too high of a gear out of corner.

I am guessing that I could make better use of the ultra high/low helix with very low gearing for off-trail, but so far I have not had the opportunity to test its best flavor. However I can attest that an aggressive helix start angle of 50 on trails was unbelievably sensitive to a weakening secondary spring. It worked ok in the beginning of the ride until the belt and clutches soon overheated and turned the engine into a turd which is to be expected. Keep asking more of the belt and it will soon overheat and in turn the secondary spring, backshift and upshift. When the secondary spring sacks, none of the backshift nor upshift woks correctly.

Note if the belt overheats, so does the primary and in turn the crankshaft, Isoflex and seals. Who cares for a short 500ft or even an 3,000 ft lake race. Although such back to back races will show major problems with the crankshaft bearings growing too tight. But how about a 200 mile day trail ride.... Are you setting this sled for racing or trail riding? For a trail setup, make sure it is not constantly running 300+F belt temps.

The harder you ride, the higher the belt temps reach. I have monitored the belt temps with hard trail riding on the 189 belt that reached abnormally high. If you think 200+F is high, think again. I ride closer to 150-200F with a the aggressive riders that raise the belt temps by at least 100F. I open up the LH panel to feel the heat of the primary and find they are on a whole other level of riding.

Of note, the stock setup is already sensitive to the secondary spring. If the secondary spring is not up to par and not performing as it should, consider it a loosing race, or much higher belt temps while trail riding. Hotter the belt, hotter the clutch sheaves, and hotter the crankshaft. I have witnessed them work without failure, but these were engines fed a lot of injection and premix oil. With the way I ride I often wonder if I could get away with 50:1 I reached 80:1 and the engine failed, so it was obviously not enough.

Hopefully this will give performance clues to draw from secondary setup. As far that I know, the 44/33 helix is a contender against the higher 240+ Hp 4S sleds. From all the secrets that I have heard, a major change in the secondary helix angles was not one of them. If you have a clutch setup with a modded helix, hopefully this will give you some clues between different clutch setups you may come across.
 

·
Premium Member
Joined
·
27,934 Posts
The Four Piece Crankshaft

From left to right, the pto shaft/stub and outer crankweb is the first piece. The inner pto crankweb and center shaft is the second piece. The inner mag crankweb is the third, and the mag outer crankweb with shaft is the fourth piece.

20210608_231227 - small.jpg

The crankpins do not count as pieces. In the same idea, if there was an independent pin that joined the two cranks, then it would be a 5 piece crankshaft. With the 995 SDI crankshaft, this center piece in part of the inner pto crankweb that is machined as a unit, hence bringing the number of pieces from 5 down to 4. Of note is the large end of the center shaft that fits in a taper into the mag inner crankweb. This is important as this is a huge 1 3/8 tapered fit that become the third area of the crankshaft that is press-fit and may need correcting. Due to the sheer size, I hope it does not need any correcting.

The main areas that need correcting to straighten a twin crankshaft are the crankpins. As far as I know, the most common correction is done with either a wedge to split the crankwebs apart, or a hammer (or equivalent device) to squeeze them together. Maize was the only one that I saw show a tool to squeeze the webs together. Picture a very large bolt cutter with the cutting end modded with two pieces of steel welder to squeeze the webs.

To tally the number of joints that need to be considered to straighten a crankshaft, there is the tapered one in the center, and two joints for each crankpin which totals 5 joints. Each of these 5 joints can bind or rather be pressed in slightly out of true. The quest is how to find which joint needs correcting.......
 

Attachments

281 - 300 of 314 Posts
Top