2013 XM Turbo

[WesG]

In Theory:At 8 lbs above atmospheric an 800cc turbo could see 80F intake temps at an ambient of 10F(-12C) *If the setup uses secondary injectors that mix the fuel and intake air prior to the intake temp location as the cold fuel evaporating and mixing cools the charge by roughly 40Deg F*. I beleive it is an etec so not all the fuel would be able to provide this cooling effect so in order to reach that 80Deg F IAT value we have to either intercool, drop the ambient temp, or increase the efficiency of the compressor. I did not do the calcs but assuming half the fuel(this is being generous) is injected pre IAT sensor giving half the 40Deg F drop(so a 20 Deg F drop) you could see 80F on the intake at roughly -5F or -20C. Also for sh1ts and giggles said machine is making 210 hp on a perfect tune at that elevation and boost.

Food for thought;
Woud you rather feed your motor 80Deg F(26.7 C) intake air when its -20C outside or colder via intercooled?!? Especially if it is not necessary?
Now lets say this machine runs in spring with the same boost and elevation but ambient air temps are say 15 Deg C (59Deg F). Now said machine is going to have an IAT of 153 Deg F(67 Deg C!!!) and make 185 HP at perfect tune.
The reality is probably somewhere in the middle for the majority of our riding. Not much riding at -20C and not much at 15 DegC.

Note
- I did these calcs at 4500 ft elevation with ambient air pressure of 12.52 psia
- These were done with my calculated airflow #'s for an 800cc two stroke operating with a VE of 85%
- Compressor efficincey was 72% as per Aerochargers compressor maps.
- These are just for fun I am by no means an expert or even close to informed so take it with a grain of salt.

 

[fredw]

yes we seen some 120 to 150f intake temps with out the intercooler and no cold air intake on longer runs at 9 psi, and became more eveident if there was no cool down time between runs.... now in the same aspect running threw the trees and such in big snow air temps stayed in line and we never seen above 125f to often

once i installed the water/air barrel cooler we seen temps drop up to 60f over previous numbers on longer pulls, but never seen a huge hp gain, that needed clutch changes or such, lag time was a bit more pronouced

last thing that was tested was adding a coldair intake, there we found our best results with running colder air to the turbo vs underhood hotter air... we seen on longer climbs that intake temps rarely went above 100f on days were ambeint temps were around the -5 to -10c... now if temps were to get to plus 10c perhaps the water/air barrel would of had much better results

the entire water/air setup deicating the front cooler added around 9 lbs with a pump to the sled, and it came at sacrificing cooler water temps for the engine, where it became very eveident down the trail, or low snow conditions...

conclusion... so far in the testing i have seen best results from from using a cold-air intake and drawing outside cold air for the aerocharger... even in over the hood snow where you think engine would be chocked off, it was not and ran very well...

we soon will be testing the new style air/air intercooler built into the airbox from aero

last year we had setup a trask kit as well and we tested the Garrett GT-2860 with and without the intercooler at 7 lbs, we learned quickly that the intercooler had did a much bigger purpose than the one on our aero kit... thus teaching us how important to stay with in the effecieny of the turbo

 

[Director]

All sounds good.. How much and where can i get one??

 

[WesG]

Those temps are with a cold air intake so that all the intake air is at ambient temperature.

FWIW- 60 degF drop in IAT at 8 lbs 4500ft. is roughly 20 HP difference due to increased air density at the lower intake temp.


Like mentioned in cold weather with a good cold air intake the intercooler will not have as large of effect. Warmer weather and higher boost levels it really comes into play (ie aerochargers test data was at 34 Deg F and showed a 38 hp difference b/w WTA and non-intercooled charge temps).

Also no one has mentioned reed life or tuning. The WTA setup should help both dramatically. Cooler IAT will be much easier on the reeds in the long run. Tuning will be much more consistant due to dampening of IAT's via the WTA(the whole volume of coolant can absorb heat from the intake air and it is snow cooled to keep removing that heat). Not to mention sleds run much better with colder air as everyone has seen (Have you rode at 26.7 C weather? How crisp was your stocker at that temp?)

Charge system fill time is something not taken into account.... We will find out this winter as a bunch of these setups will be running around. I know on my setup I will be loosing charge system volume due to the exchanger being installed in the current setups airbox, this should decrease the time to max boost. If you went from a non-intercooled setup and added volume via a WTA exchanger I could see that delaying boost rise not only from the added charge system volume/pressure drop through the exchanger but from the added airflow requirements due to the more dense air in the manifold. But again you are feeding the motor more dense air at lower boost pressures on your way to max boost so you will be making more power as you come up to max boost thus potentially negating the perceived slower rise to power. Field testing would be the king of balancing your system here not theory.

 

[fredw]

reed life has not really been a issue anymore since replacing stock reeds with a aftermarket reeds or a moded reed... and even with guys that are running intercoolers or water/air coolers, they still need a aftermarket reed... but yes your correct in the cooler a charge the better

as for tuneing even with no cold air intake and seasonal -5c ambeint temps, there was no real ulgy spots in tuning where it seamed excessivly rich or lean, and became 12.86 to 13a/f average number... but more lag off the start was evident

now where i seen issues was going down hill threw deep snow on the exhaust side... if you came to a stop, you would have a gargle, and that same problem was evident on the other two turbo manufactures i drove as well.... as for the aerocharger once the cold air intake was installed that issue was gone(thinking that the exhaust gases under the hood were the issue)

few other points of intrest... have you looked inside the a/w airbox... when i did the very first thing i said to kyle was that it looks like a restriction to air movement, (full of cores) but he assured me its not...
but even with the water/air barrel i tried there was a restriction... here was some info on it...

Recommended for up to 390 CFM and 300 HP
Pressure Drop: 1.1 PSI.
Core type: Tube and Fin
Air Inlet/outlet: 2.25"
Water Inlet/Outlet: 1/2" NPT Female
Maximum water/air pressure: 70 PSI
Core Size: 10" long x 4" (Endtanks add to length)

then the kit i used Barrel Water to Air Intercoolers needed the front heat exchanger didicated to it, that means less cooling for the motor... and the conditions we had down the trail i overheated.. once in the deep it was ok

now i wish i would of added a few three way valves to the kit to only use front cooler when i needed it, and turn it back to engine if needed... i also would of like to run straight methanal in the dedicated cooler

this was my own testing and data, and was set up by myself, so take it as that..

 

[SkiDoozer]

you are all forgetting that aero charger sucks.... worst turbo system ever!!! complete junk!

 

[mach123]

you are all forgetting that aero charger sucks.... worst turbo system ever!!! complete junk!

Pretty vag, explain if you think that..........WHY

 

[deaner]

you are all forgetting that aero charger sucks.... worst turbo system ever!!! complete junk!

Well, now that we have feedback from our resident rocket scientist.......its settled.

 

[WesG]

OK so assuming Trask uses a 2860rs, ambient temp of -10C or 14 Deg F, perfect cold air intake, 9 psig, 6500 ft (roughly 11.5 psia), 8200 rpm, 800cc 2 stroke, 86% VE (taken from Brads other post, I was using 85% previously and have had #'s very close to Brads). According to garretts performance maps it would fall in the 76% eff. range at these conditions.

The aero performance map (taken from their website for the 200% compressor) shows it at 70% eff. at that point. Thus the aero would build more heat. Roughly 10 Deg F more. 136 to 126. Is that a game changer, not imho but it does show that the garrett is more efficient in operating at those conditions. This suggests that Trask is either not using the 2860rs, or they have other issues with their overall setup ie a large pressure drop somewhere, etc.

Good field data FredW. This would suggest that the pressure drop across your WTA setup was significant in increasing charge system fill time (lag) also the increased demand for air due to the colder more dense intake air would potentially increase this effect. Maybe the VATN needs to be adjusted to suit this setup... I can tell you that a 60 DegF drop in intake temp is worth roughly 20 HP... So I have to ask was there no increase in rpm or trackspeed with the WTA? With a big track I suspect 20 hp is only a few MPH more trackspeed. Ie with my apex 12 to 15 lbs with a 162 2.5 CE was approximately 3-5 mph trackspeed, but a large difference on the hill. It was also worth 3-400 rpm but keep in mind that will be a larger rpm difference than the 800 would see because of the gear reduction to the clutch on the apex (and the 3 lb increase is more than 20 hp). It also looks like the etec requires the front cooler so I would suggest installing a dedicated cooler for your WTA exchanger. I don't know how the etec responds to higher coolant temps and this could be coming into play (power-wise) with the removal of the front exchanger from the cooling loop. Your cold air intake sounds like a huge benefit to the system, this i can totally see as you mentioned sucking in exhaust when going downhill (now not only is it hot it has much less oxygen available for combustion), and increasing the crispness of the sled. This is exactly what I noticed when installing a cold air intake on my BD apex setup, much crisper response (colder more dense air).

I do question the aerochargers VATN application for the snowmobile world, as Brad mentioned it is alot different than the auto world. IE in the auto world you are in one gear and slowly (compared to a cvt) moving through the rpm range in each gear resulting in vastly different flow rates for the same PR. As he also mentioned you basically only care about one point on the comp. eff. map and thus one point on the turbine map(this is not completely true but it is much less relevant with the cvt) How long is a snowmobile actually on its way to max rpm? How efficient is the VATN at these flows and PR's? I see no published data on this anywhere.... How small can the VATN make the A/R, how big can the VATN make the A/R? Is the VATN not able to open the A/R up enough to allow as efficient flow as a fixed A/R with a wastegate in our applications ie choking the turbine resulting in excessive pipe pressures and heat? Just looking for info, not bashing. In theory the VATN should be a vast improvement but in the field it has not been this way yet.

 

[fredw]

well after reading a few post, i am looking forward to the new season, trash talk is flying around, and some are absoultey clueless in the turbo era,(read threw it) will make for an intresting year to say the least

one thing i stress for first time buyers of turbo kits........... try before you buy, because no two kits are equal, and you better be able to troubleshoot...... if your a guy that takes his vehicle to a shop when you see a drop of oil on the driveway... i bet a turbo is not for you

 

[Aerocharger_Brad]

Pretty vag, explain if you think that..........WHY

Check his post. TSS guy. Easy everybody snow is coming and we can all ride then. Proof is always on the snow. We will be having sevral Turbo demo days at CKMP this year. Come ride one. Even Fredw is invited.

 

[fredw]

here is a video after coldair intake was installed and vatn set at 2 1/4 turns out, with this setup on/off throtle is very quick, and that is with 25grams pin weight and a three inch track with 2/1 gearing
Freddy's 800 E-TEC Aerocharger Turbo - YouTube

OK so assuming Trask uses a 2860rs, ambient temp of -10C or 14 Deg F, perfect cold air intake, 9 psig, 6500 ft (roughly 11.5 psia), 8200 rpm, 800cc 2 stroke, 86% VE (taken from Brads other post, I was using 85% previously and have had #'s very close to Brads). According to garretts performance maps it would fall in the 76% eff. range at these conditions.

The aero performance map (taken from their website for the 200% compressor) shows it at 70% eff. at that point. Thus the aero would build more heat. Roughly 10 Deg F more. 136 to 126. Is that a game changer, not imho but it does show that the garrett is more efficient in operating at those conditions. This suggests that Trask is either not using the 2860rs, or they have other issues with their overall setup ie a large pressure drop somewhere, etc.

Good field data FredW. This would suggest that the pressure drop across your WTA setup was significant in increasing charge system fill time (lag) also the increased demand for air due to the colder more dense intake air would potentially increase this effect. Maybe the VATN needs to be adjusted to suit this setup... I can tell you that a 60 DegF drop in intake temp is worth roughly 20 HP... So I have to ask was there no increase in rpm or trackspeed with the WTA? With a big track I suspect 20 hp is only a few MPH more trackspeed. Ie with my apex 12 to 15 lbs with a 162 2.5 CE was approximately 3-5 mph trackspeed, but a large difference on the hill. It was also worth 3-400 rpm but keep in mind that will be a larger rpm difference than the 800 would see because of the gear reduction to the clutch on the apex (and the 3 lb increase is more than 20 hp). It also looks like the etec requires the front cooler so I would suggest installing a dedicated cooler for your WTA exchanger. I don't know how the etec responds to higher coolant temps and this could be coming into play (power-wise) with the removal of the front exchanger from the cooling loop. Your cold air intake sounds like a huge benefit to the system, this i can totally see as you mentioned sucking in exhaust when going downhill (now not only is it hot it has much less oxygen available for combustion), and increasing the crispness of the sled. This is exactly what I noticed when installing a cold air intake on my BD apex setup, much crisper response (colder more dense air).

I do question the aerochargers VATN application for the snowmobile world, as Brad mentioned it is alot different than the auto world. IE in the auto world you are in one gear and slowly (compared to a cvt) moving through the rpm range in each gear resulting in vastly different flow rates for the same PR. As he also mentioned you basically only care about one point on the comp. eff. map and thus one point on the turbine map(this is not completely true but it is much less relevant with the cvt) How long is a snowmobile actually on its way to max rpm? How efficient is the VATN at these flows and PR's? I see no published data on this anywhere.... How small can the VATN make the A/R, how big can the VATN make the A/R? Is the VATN not able to open the A/R up enough to allow as efficient flow as a fixed A/R with a wastegate in our applications ie choking the turbine resulting in excessive pipe pressures and heat? Just looking for info, not bashing. In theory the VATN should be a vast improvement but in the field it has not been this way yet.

 

[SkiDoozer]

They are a poor kit. The air box blows off. The snow/air set up is a butcher job on a good sled. We it become a reliable set up then you can call it good. Total waste of money/performance. Wrench, wrench, wrench.

 

[E-Zmoke]

here is a video after coldair intake was installed and vatn set at 2 1/4 turns out, with this setup on/off throtle is very quick, and that is with 25grams pin weight and a three inch track with 2/1 gearing
freddy's 800 e-tec aerocharger turbo - youtube

lmao....

 

[fredw]

ya the first ride i had the airbox slip off the back of the carbs as well, but it became a great spot to store the spare belt after that and no more issues, the snow air is not out yet, have you seen them? as for performance i been on the others and they are no dog... and they dont cost no 8grand, the flagship year had some issues, but last year has been great and this comming year hopfully even better..

They are a poor kit. The air box blows off. The snow/air set up is a butcher job on a good sled. We it become a reliable set up then you can call it good. Total waste of money/performance. Wrench, wrench, wrench.

 

[fredw]

LOOKING AT dynotech tonight they ran a turboed etec on the dyno in the spring with a garett ball bearing turbo along with intercooler. like the aero they made around the 240hp@8lbs boost at sea level

even at 5 lbs they were making over 200hp. and that could probally be done on pump gas, that is more power than most bb will do right there...

 

[mach123]

Check his post. TSS guy. Easy everybody snow is coming and we can all ride then. Proof is always on the snow. We will be having sevral Turbo demo days at CKMP this year. Come ride one. Even Fredw is invited.

Well tell us when the demo days are so we can book in advance and get the time off.

 

[The Kickass One]

WOW! Actually Double WOW!! Without the TURBO!!, you could never ride that terrain!! LAME!!

 

[Aerocharger_jerry]

Well tell us when the demo days are so we can book in advance and get the time off.

Hey mach123, thanks for your interest in the CKMP Aerocharger demos. We're working the dates for these around Aerocharger's race schedule this season - shoot us your email, and we'll keep you updated as soon as we get these days on our calendar.