TurboKeith
Pro
I know there has been a lot of argument on the subject lately and each system seems to have its benefits. The big benefit for the front mount is supposed to be throttle response. I'm curious about how much throttle response you lose when you are running higher boost numbers. The reason I ask is that on my last turbo sled which was an 800 RMK, I had to run pretty heavy weights in the primary clutch to get the power to the ground. This was of course a front mount but I still had a little bit of lag. The heavy weights really mess with responsiveness. I had to bring the engagement up a bit to make it work right. When I ran in the lower boost numbers like 7-8 psi, I ran lighter weights with a lower engagement and throttle response was always great. Maybe this isn't an issue with the big 4 strokes???
Couldn't you just clutch around any lag issues on the rear mount like I had to on my 800? Higher engagement makes a huge difference in responsiveness.
Couldn't you just clutch around any lag issues on the rear mount like I had to on my 800? Higher engagement makes a huge difference in responsiveness.
snowy1
TY 4 Stroke Guru
I put a bigger turbo on my front mount and welded 8 gr. on the end of each wieght and did not notice any difference in response it still has no lag
Mountaintech
TY 4 Stroke God
PM Snowmotion about your concern. He rode a bunch of turbo's at the BDSO (Big Dawg Shootout) including mine. He can give you an unbiased opinion as he is also in the market.
snowbeast
TY 4 Stroke God
- Joined
- Apr 13, 2003
- Messages
- 5,498
- Age
- 69
- Location
- E waterboro,maine
- Country
- USA
- Snowmobile
- 2015 apex xtx traded for a 2017 sidewinder L-tx-le
- yes
- YOUTUBE
- yes
Hey rx fun is that MCX400 the big boy turbo from MC-Exspress?? HOw much hp @ what boost.RX FUN said:
Mountaintech
TY 4 Stroke God
Yup, the first season of the rear mounts from MC saw them delivered with the bigger turbos which became an upgrade for the following year (this past season). A friends identical sled was dynoed at 221hp @ 9lbs.
Ted Jannetty
TY 4 Stroke God
There is absolutely no arguing with, that the closer the turbo is to the engine the faster the response time.
ON a Steady State Dyno Pull the Same turbo will make the Same power regarless of location, ONCE everything (Temperature) stabilizes
Heat energy and exhaust velocity is what drives the turbo charger and the farther away from the source the more of it is lost before doing work.
So it's a TIME to full power factor NOT a power factor
Here is another little known fact, Stainless steel headers always make more power than mild Steel, REASON, Stainless steel reflects a higher pecentage of heat than mild steel, meaning it keeps the heat inside the pipe better.
The reason for the big push on thermal coating of mild steel headers, it works.
The more heat you keep in the header the faster the exhaust gasses can travel.
Take things a step further and coat your stainless header.
ON a Steady State Dyno Pull the Same turbo will make the Same power regarless of location, ONCE everything (Temperature) stabilizes
Heat energy and exhaust velocity is what drives the turbo charger and the farther away from the source the more of it is lost before doing work.
So it's a TIME to full power factor NOT a power factor
Here is another little known fact, Stainless steel headers always make more power than mild Steel, REASON, Stainless steel reflects a higher pecentage of heat than mild steel, meaning it keeps the heat inside the pipe better.
The reason for the big push on thermal coating of mild steel headers, it works.
The more heat you keep in the header the faster the exhaust gasses can travel.
Take things a step further and coat your stainless header.
TurboKeith
Pro
Does the front mount require a pump for oil return like the rear mounts or is it just a gravity return to the oil tank? The rear mounts have the length of the exhaust feeding the turbo going against them but they seem to benefit from having an aluminum charge tube in the tunnel to help cool the intake air. Does the extra cooling effect return a noticable performance improvement?
Ted Jannetty
TY 4 Stroke God
No oil pump required, gravity feed back to valve cover oil filler cap.
I don't think there is much benefit at all, here is why.
Average air inlet temps 20 degrees, 11 degrees increase per pound of boost, average boost 10 psi, 11x10=110 degree discharge temps.
Average intercooler efficiency at 20 degree air temps around 80% net charge air temps 22 degrees.
Only a 2 degree increase.
You can't get the charge air temps lower than air inlet temps when it's that cold outside even with the help of melting snow which is 33 degrees.
When outside air is 80 degrees we can use ice intercoolers to get charge air temps below outside air but only up to certain boost levels.
I don't think there is much benefit at all, here is why.
Average air inlet temps 20 degrees, 11 degrees increase per pound of boost, average boost 10 psi, 11x10=110 degree discharge temps.
Average intercooler efficiency at 20 degree air temps around 80% net charge air temps 22 degrees.
Only a 2 degree increase.
You can't get the charge air temps lower than air inlet temps when it's that cold outside even with the help of melting snow which is 33 degrees.
When outside air is 80 degrees we can use ice intercoolers to get charge air temps below outside air but only up to certain boost levels.
slacker: Take a look at this post it should answer some of your questions about Turbo chargers and how they work. Some of the information will assist you coming to conclusions with some of your questions
http://www.ty4stroke.com/viewtopic.php?t=14389
http://www.ty4stroke.com/viewtopic.php?t=14389
Turbo Tim
TY 4 Stroke Master
I have 1 of each ..........I'd be glad to answer any Specific questions you have .
TurboKeith
Pro
JTSRX,
That's a good post. Actually I've been around turbos quite a bit for the last couple of years on snowmobiles as well as cars. Hell I even built my own closed loop electronic boost controller. The 4 stroke sled with a turbo is new to me. I'll probably end up building my own setup and the forum is probably going to be the cheapest part of the education process.
Turbo Time,
If you already have a front mount and a rear mount, why are you going with the supercharger?
That's a good post. Actually I've been around turbos quite a bit for the last couple of years on snowmobiles as well as cars. Hell I even built my own closed loop electronic boost controller. The 4 stroke sled with a turbo is new to me. I'll probably end up building my own setup and the forum is probably going to be the cheapest part of the education process.
Turbo Time,
If you already have a front mount and a rear mount, why are you going with the supercharger?
Turbo Tim
TY 4 Stroke Master
slacker said:
1 : No underhood heat 2 : No loss of fuel tank capacity 3: No lag- (this does not apply to the front mount turbo which also has no lag).4:stock exhaust from engine to tailpipe. 5 : I already have 2 Turbo sleds .
I could easily change my mind and go with a frt mount turbo though depending on what I see come out .........I'll never have another rear mount turbo though.
ken_climb
TY 4 Stroke Junkie
Why not another rear mount? Other then off the line they make alot more power. 
When i'm climbing I don't need the hole shot
When i'm climbing I don't need the hole shot
Turbo Tim
TY 4 Stroke Master
ken_climb said:Why not another rear mount? Other then off the line they make alot more power.
It's hard to explain unless you regularly ride both types , I find that the rear mount throws my timing off on jumps, carving , and generally just playing around . Unbeatable for long pulls up mountains , lake racing etc. though .
snowy1
TY 4 Stroke Guru
not knocking the rear mount but a front mount will make just as much power as a rear mount, if you have the same size turbo and no lag.
