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Discussion Starter · #1 ·
The early 600 ACE prototypes said "4-TEC" on the mag side engine cover, so I guess I can post this here. I was disappointed in the initial stages of researching this by the lack of information regarding the results of the few turbo 600 ACE sleds that supposedly exist out there. We don't have anything to sell you, so hopefully our show and tell will get the shops to come out of the woodwork.

Our goals are a bit different than most posting in this forum. Since we're competing in SAE's Clean Snowmobile Challenge, our goal is to maintain (or better) the stock sled's fuel efficiency and quietness while continuing to improve upon emissions and the ability to run the competition's random ethanol blend. Last year we placed second overall with a Renegade 600 ACE with our ProEFI 128 standalone, flex fuel sensor, and exhaust system with catalysts and lightweight muffler. Our calibration pushed the lean-burn operation even further beyond BRP's calibration and it payed off for an emissions score almost as high as a diesel and another sled running stoichiometric. It made 57hp peak, so our modifications maintained stock power. We scored poorly in performance-based events, however. So this year we're switching to an MXZ chassis and adding some boost.

For maximum efficiency, we have chosen to maintain the stock 12:1 static compression ratio but have made other changes to reduce combustion pressure. The turbocharger is a GT1241, selected as result of a turbo matching excercise. It has required a healthy amount of internal wastegate porting to prevent it from making more boost than desired above 6000 rpm (I've seen 92hp as result of boost creep). All testing under boost thus far has been performed on E85. The main injectors are 347 cc/min and we have an upstream 387 cc/min injector mounted near the compressor for our charge cooling. No intercooler until we dermine that it is necessary.

Here's the latest video of a WOT sweep:
And a power curve at 10 psi peak:
Our changes to the valvetrain, in-house fabricted aluminum intake manifold, and backpressure from the GT12 have reduced power from the stock 57 hp on our Land and Sea Dynomite.

Changes to come include electronic throttle control and the implementation of our own ECU software. Stay tuned!
 

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Very interesting stuff. I wouldn't think running on e85 cruising running over Stoich wouldn't be an issue . We have been able to get away with 1.00 lamba while cruising without any issue (although our static comp. is 10:1). Actual near 16 AFR has been safe making six pounds of boost on a 1500 cc 4 tec.

I wonder if you would benefit from an electronic t-stat for the emissions\economy part of the test. I don't know if you've looked at the Chevy 1.4Turbo ECU logic but while cruising they raise the temp of the engine near 235 degrees to help promote combustion (these stats are 0 to 5 volt operated and very small so I think with a little work it would be doable). Fully programmed dependent on boost, iat,cat and tps.

Keep us posted on your progress!
 

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Looking good Birt. Diggin the new floor!
 

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Discussion Starter · #4 ·
Thanks, Puller! We'll have to look into the electric thermostat--data logs from last year show the Renegade 600 ACE hovering around 160 F while cruising.

Thanks, Matt. The floor's probably the best they could have done without a long shutdown to do a proper epoxy coating. I keep losing wastegate circlips in it though...
 

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Discussion Starter · #6 ·
We made our maiden boosted voyage today! The sled is quick and as quiet as stock with a bit of turbine whir. Check it out:


 

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Very nice! When is this challenge happening and can anyone attend? In any case keep us posted on your progress!
 

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Discussion Starter · #9 ·
Thanks, guys!

Here's some details, Puller:

http://students.sae.org/competitions/snowmobile/about.htm

http://www.mtukrc.org/snowmobile.htm

KRC Keweenaw Research Center
1400 Townsend Drive
Houghton, Michigan 49931
March 4-9, 2013

Spectators are welcome at all Collegiate Design Series competitions. Admission is free.

Access to designated Team Paddocks is limited to "Registered Attendees" and considered a "Restricted Area". A "registered attendee" is anyone 18 years of age or older, has signed the liability waiver and has been issued a wristband from the registration area.

No one under 18 years of age may enter the paddocks.
 

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Very cool! We be up there that whole week trail riding. It would be interesting to stop by for the day and see what unique ideas the young engineers have came up with!
 

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Discussion Starter · #11 ·
Excellent! We all love talking about our setups and, even though our sleds are "slow" because we're limited to 130 hp and scored on emissions, noise, and fuel economy, there will be lots of interesting sled technology on display. There will be 3 turbo 600 ACE's (ours with ProEFI 128, Wisconsin with MotoTron and MAF, and Clarkson with the PCV Pti and lowered compression), 2 Weber 750 turbo-powered Rush chassis sleds (MTU with AEM and RIT with ViPec), a 660 turbo Cat motor in a XP Renegade chassis (Waterloo with MoTeC), and a smattering of etec's, NA 4-strokes, and full electric sleds. I just realized how diverse this competition is after typing that--pretty cool!
 

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One question to you mbirt, why did you limit your RPM on the power curve to approx. 7500. Isn't a square engine could take a higher RPM. I know that BRP had limited their ACE engine to that ±7500RPM but why not try to go a little higher? something like 7800
 

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Discussion Starter · #13 ·
One question to you mbirt, why did you limit your RPM on the power curve to approx. 7500. Isn't a square engine could take a higher RPM. I know that BRP had limited their ACE engine to that ±7500RPM but why not try to go a little higher? something like 7800
At our competition, during the dyno emissions test, a WOT sweep is performed to find the peak power speed and then the engine is held at peak power for 2 minutes for the first mode of emissions measurement--so some work goes into shaping the power curve for the test. We've certainly revved the 600 ACE past 7500 rpm on a standalone ECU (7800 IIRC) but wouldn't dare hold it there for 2 minutes with boost.
 

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At our competition, during the dyno emissions test, a WOT sweep is performed to find the peak power speed and then the engine is held at peak power for 2 minutes for the first mode of emissions measurement--so some work goes into shaping the power curve for the test. We've certainly revved the 600 ACE past 7500 rpm on a standalone ECU (7800 IIRC) but wouldn't dare hold it there for 2 minutes with boost.
Why not?

Also...what limits you to 130hp?

The motor, or the rules of the competition?

Thanks.
 
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