A Few MPI Turbo Questions: Heat / Intercooler / PCV-PTI

[jeffgilbert]

That's correct, I don't think a intercooler is worth it at stock boost levels on the trail kit at least for me its not. Here is why. They way most of our group rides is low speed off trail playing around in meadows, hills and in the trees. There is very little air flow to begin with and lots of heat under the hood so with the stock trail kit and the air intake outside of the sled the compressor is already being feed nice cold dry air. This combination runs cool all the time. Now just think if you had the air intake under the hood. Your already starting with hot steamy air at the intake before you even get started. Next run that hot air through a intercooler that under the hood in area that's hot to begin with and in my case in getting any air flow through the radiator so I would be actually heating up the air even more and that kinda defeats the purpose. Intercoolers work great but only when you get air flow, depends on how you ride. This picture was a ride few months ago and is pretty common. Take a look at my radiator and notice its pretty much plugged with snow and no air flow, if I had a intercooler under the hood the only thing it would be doing making my wallet thin. Just my 2 cents.
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Thanks yamahaguys this is some good input I was looking for with the intercooler can the intake be ran though the hood to or is it only underhood? I still think I might benefit from the intercooler because I only run into deep fresh powder like that a few times a year and I do a lot of high speed driving and ditch banging but on the other hand there is a lot of slow tight trails I have to go through in my area as well and like you said no amount of air going across the intercooler doesn't really make it worth it. I'd like to hear from someone that had installed the intercooler after having the trail kit on and hear if they think it was money well used. Is there and room to mount a fan on the intercooler I haven't seen one up close.

 

[jeffgilbert]

At 6 pounds you're already getting close to the limits of the stock fuel system. Stock compression can support a bit more but don't push that line cuz bad things can happen! I'm referring to the mpi turbo, the hurricane turbo for example with the bigger injectors is 100% safe at 6 pounds.

So if you get into adding more fuel like a 4th injector or larger injectors what is the highest amount of boost you can run without lowering compression? What about pulling some timing with an ignition module?

 

[Studroes144]

So if you get into adding more fuel like a 4th injector or larger injectors what is the highest amount of boost you can run without lowering compression? What about pulling some timing with an ignition module?

Id talk to a builder/tuner with those questions. One thing I can say with my stage 2 setup is that it sure is a big peace of mind knowing that if I'm not comfortable with say a gas station on the trail and fuel quality, I can easily turn it down and be 100% safe since the compression is lowered. If you really want to make power don't go half way, do it right the first time.

 

[jeffgilbert]

Id talk to a builder/tuner with those questions. One thing I can say with my stage 2 setup is that it sure is a big peace of mind knowing that if I'm not comfortable with say a gas station on the trail and fuel quality, I can easily turn it down and be 100% safe since the compression is lowered. If you really want to make power don't go half way, do it right the first time.

I'm on the same mind as you do it right the first time. I spent a pile of money building a n/a set up and when I put that to the max and it wasn't enough power I turned to boost. I'm think I should go with the intercooler and invest in a PCV-PTI along with my ignition module over the summer that way come next winter I'll have the best possible set up for stock boost and if I want to go further then I will be 70% there and only need to lower compression and add a bit more fuel.

 

[Studroes144]

I'm on the same mind as you do it right the first time. I spent a pile of money building a n/a set up and when I put that to the max and it wasn't enough power I turned to boost. I'm think I should go with the intercooler and invest in a PCV-PTI along with my ignition module over the summer that way come next winter I'll have the best possible set up for stock boost and if I want to go further then I will be 70% there and only need to lower compression and add a bit more fuel.

I can promise you, you'll want to go further lol. Only thing left would be 4th injector or bigger injectors and head shim (unless you decide to go full blown rods and Pistons) so you're looking at another $500 in parts and just the extra time/labor for the head shim, since the sled will be all apart there's no better time than now. I loved my viper at 5-6 pounds, really responsive, quick and good top end when geared properly, and still I always wondered what it would feel like with yet another 60 hp increase, and now that I know, it's awesome!

 

[jeffgilbert]

I can promise you, you'll want to go further lol. Only thing left would be 4th injector or bigger injectors and head shim (unless you decide to go full blown rods and Pistons) so you're looking at another $500 in parts and just the extra time/labor for the head shim, since the sled will be all apart there's no better time than now. I loved my viper at 5-6 pounds, really responsive, quick and good top end when geared properly, and still I always wondered what it would feel like with yet another 60 hp increase, and now that I know, it's awesome!

I got a felling that after a year on low boost I may want to increase you can never have too much power lol I was planing on going with 24/49 gears over my stock 21/49 in the rtx LE this way I shouldn't loose the bottom end grunt that I love about the rtx LE and still gain a bit on top 105 mph is lots of speed for me much better the the 88mph I'm seeing now on a good day. What belt are you running? I found mine best responds to the 8jp over the 8dn but I was thinking of trying the gates belt some people are saying it grabs that much better I don't mind changing a belt every 600-1000 miles because I give them a lot of abuse doing wheelies and long wot runs.

 

[Studroes144]

I got a felling that after a year on low boost I may want to increase you can never have too much power lol I was planing on going with 24/49 gears over my stock 21/49 in the rtx LE this way I shouldn't loose the bottom end grunt that I love about the rtx LE and still gain a bit on top 105 mph is lots of speed for me much better the the 88mph I'm seeing now on a good day. What belt are you running? I found mine best responds to the 8jp over the 8dn but I was thinking of trying the gates belt some people are saying it grabs that much better I don't mind changing a belt every 600-1000 miles because I give them a lot of abuse doing wheelies and long wot runs.

I preferred the 8jp belt on my sled in stock form and never had an issue, with the turbo was a different story. 8jp belts only lasted 200 miles before they blew to chunks, one made a nice hole in my lower side panel so it was an expensive blown belt. Since then I ran the gates carbon belt and 8dn belt. Carbon belt posted the best top speeds but the 8dn was quicker and more responsive on my sled. Got 800 miles out of the 8dn before it just started to pull the cords a bit. Beating the crap out of a $50 belt for 800 miles is something I'm perfectly fine with!

 

[jeffgilbert]

Well thats good to know I got a 8DN on the self with only 150miles on it i can get 8DN and 8JP for around the same price of $90 cad tax in.

 

[Yamadog]

So if you get into adding more fuel like a 4th injector or larger injectors what is the highest amount of boost you can run without lowering compression? What about pulling some timing with an ignition module?

I am running MPI Stage I with intercooler, upgraded fuel pump and 4th injector and evo flash to pull timing and raise rev limiter on my 15 XTX with stock motor and no head shim. I am running 7 lbs on pump gas at almost 230 hp and 10.5#'s on race gas at over 260 hp. This sled makes a lot more hp at lower boost than my 14 does with low comp pistons with the same turbo set up.

 

[stone88]

I am running MPI Stage I with intercooler, upgraded fuel pump and 4th injector and evo flash to pull timing and raise rev limiter on my 15 XTX with stock motor and no head shim. I am running 7 lbs on pump gas at almost 230 hp and 10.5#'s on race gas at over 260 hp. This sled makes a lot more hp at lower boost than my 14 does with low comp pistons with the same turbo set up.

Not sure how you are getting 230 hp on 7# that's a lot of power over stock, will be more like 200 hp. I have been running 7# on 91 pump on my 2014 with a hurricane turbo on it. No where near 230 hp.

 

[Big_Phil]

I am running MPI Stage I with intercooler, upgraded fuel pump and 4th injector and evo flash to pull timing and raise rev limiter on my 15 XTX with stock motor and no head shim. I am running 7 lbs on pump gas at almost 230 hp and 10.5#'s on race gas at over 260 hp. This sled makes a lot more hp at lower boost than my 14 does with low comp pistons with the same turbo set up.

Hey how long have you had the evo flash on your sled for?

And sorry, dont mean to #*$&@ talk or anything, so please dont take the wrong way. But where does this 230hp on pump gas at 7psi come from?

Did you change your turbo? I understand youre at stock compression, but you pulled timing with the evo flash.

Did you change or modify your turbo? That mitsubishi 15g that comes with the mpi kits isnt good for much more than 250hp before it starts blowing hot air.

 

[Srxspec]

He has a Ulmer billet wheel on his MPI turbo (equivalent to a 20T wheel), MPI race can, and Ulmer header. I don't have an engine dyno, but 130 hp to the track on my chassis dyno. 130 ÷ 0.57 (clutch efficiency) = 228 hp.

 

[Big_Phil]

He has a Ulmer billet wheel on his MPI turbo (equivalent to a 20T wheel), MPI race can, and Ulmer header. I don't have an engine dyno, but 130 hp to the track on my chassis dyno. 130 ÷ 0.57 (clutch efficiency) = 228 hp.

Wow, thats some pretty impressive number for low boost like that. I stand corrected!

 

[Yamadog]

Yes this one is making a lit more usable power at less boost than th 14 did the billet turbo made a huge difference i believe and with the stick motor it us much snappier than the low compression motor in the 14 at rhe flick of the throttle coming out of a turn with 1.6" track 150 screw in studs and 144 grand master studs can spin thr trACK and bring the rear around

 

[Yamadog]

Hey how long have you had the evo flash on your sled for?

And sorry, dont mean to #*$&@ talk or anything, so please dont take the wrong way. But where does this 230hp on pump gas at 7psi come from?

Did you change your turbo? I understand youre at stock compression, but you pulled timing with the evo flash.

Did you change or modify your turbo? That mitsubishi 15g that comes with the mpi kits isnt good for much more than 250hp before it starts blowing hot air.

Read Allen's post above he built it for me and there is a lot of upgrades to it the billet wheel being the biggest improvement in the turbo. The evo flash has 1 season on it now and about a 1000 miles I really like it. I can over rev a bit when the switch is on 10.5 #'s of boost and not bang off the limiter and I am running race fuel at that setting but am not worried about detonation because of the timing pull.


And you are correct when we pused the 14 to 13 #'s the ratio hp/ #'s of boost dropped off as we got close to its max output. I am still waiting on MR. ULMER to finish the 14 for racing and we arte trying to push that one to the neighborhood of 20#'s on a CAT turbo or whatever he ends up sticking in the thing!!!!