MPI/Yamaha Viper turbo upgrades 250hp

[matt@mpi]

Starting with the base MPI turbo kit offered through Yamaha you have options to build 250hp using the original turbo. We installed the intercooler, stronger waste, fuel pump, and 4th injector to achieve these results. All of these parts and be purchased individually to reach your desired results.

The intercooler upgrade kit includes everything you need to make the upgrade: Intercooler, stronger waste gate, Billet blow off valve, hoses, and everything you need to complete the upgrade. The intercooler is a must have when wanting to run anything over 8# of boost.
MPI part# mtv-1100 $1449.00

The fuel pump kit is also needed we trying to run over 8# of boost. This pump kit uses a return style with a 1:1 regulator so you have the right fuel pressure at the rail based on boost pressure.
MPI part #HSK-1168 $319.95

The 4th injector kit will deliver extra fuel based on boost pressure. Typically the trip point for this injector to kick in is around 10# of boost. This 4th injector allows for the stock injectors to remain in place. This is a great way to deliver extra fuel beyond what the factory injectors can deliver. This allows the stock injectors just to do their job and maintain proper idle, cold start, hot start, and off idle performance.
MPI part #HSK-1169 $449.00


For those that would like to stay on pump gas we offer a thick head gasket and head stud kit. We offer to different thickness based on altitude. The stock head bolt should never be re-used so included in the kit will be a set of high quality ARP studs, washer, and nuts.
MPI part #HSK-1170 $299.99 6000/ft+
MPI part #HSK-1171 $299.99 Below 6000/f

 

[Tricky Nick]

How are you getting air to pass through the intercooler to cool the charged air. Is there a fan behind the intercooler. Doesn't seem like there would be much air circulating under the hood where the intercooler is positioned

 

[loudelectronics]

Why not just use larger injecters like Geisick Performance Injectors. I use them on my race motor builds. Lots more fuel when needed but so finite that fueling at idle is not a problem.

 

[Mountaintech]

That is a weird spot to put the 4th injector.

 

[matt@mpi]

How are you getting air to pass through the intercooler to cool the charged air. Is there a fan behind the intercooler. Doesn't seem like there would be much air circulating under the hood where the intercooler is positioned

You can trim out the plastic under the headlight for more air flow across the intercooler. I watched this intercooler pull out 60* on the dyno with no airflow going across it with ambient temps around 70*.

 

[matt@mpi]

That is a weird spot to put the 4th injector.

Maybe so? But it works really good.

Why not just use larger injecters like Geisick Performance Injectors. I use them on my race motor builds. Lots more fuel when needed but so finite that fueling at idle is not a problem.

Race motor? Since when do we care about idle or cold start when you in the middle of nowhere on a race motor? Large injectors SUCK without being rescaled. If you want to run them that's your call, but in our testing we found its not the way to go.

This injector only turns on at higher boost levels around 10# of boost. So idle, cold start, hot start, etc aren't effected by larger injectors.

 

[Adams574]

So with everything I have just read your saying the stock kit from yamaha is good up to 8# of boost before leaning out? Or does this require using race fuel or something? Running 8# should be around 207hp using the 9hp per lb on top of the stock 135hp. I will have a boost gauge and an AEM AFR on my sled to keep a good eye on the numbers. What would you say safe operating range should be?
Thanks

 

[Myrdin]

What is boost/hp is possible without head shim? I am interested in saving that project for summer, this winter I want spend my time riding, but the rest is doable. I guess there are two scenarios, one with race gas and one with pump, using all the goodies and the electronic boost controller.

 

[Studroes144]

This thread just stopped cold turkey apparently, very interested in doing the fuel pump upgrade. For anyone that's done it can you shed some light on the process. I have stage 1 kit now, but I'm finding that 5 pounds is all I can run for boost, gems controller is maxed out and on longer runs the afr starts to creep up. I have a thicker head gasket and head studs already installed, looking to run 8 pounds on pump fuel. Will the fuel pump upgrade get me there?

 

[fbkakrdr]

Just installed the stage 1 with the upgraded fuel pump last week. Ran 8 pounds at 400 feet for most of the day today, AFR's stayed right in the 11.5 to 12.5 area thru the entire throttle range. I do use torco accelerator to bump octane levels up 100 to 105, but with the head shim you may be able to pull off 8 pounds on pump gas. Matt from MPI would probably know best.

 

[dlinebacker36w]

Yeah i d love to move up from the trail turbo HP but want to stay on pump gas so hopefully that is possible for under 2 g

 

[Adams574]

Just installed the stage 1 with the upgraded fuel pump last week. Ran 8 pounds at 400 feet for most of the day today, AFR's stayed right in the 11.5 to 12.5 area thru the entire throttle range. I do use torco accelerator to bump octane levels up 100 to 105, but with the head shim you may be able to pull off 8 pounds on pump gas. Matt from MPI would probably know best.

Seems like an AFR of 12.5 is pushing it alittle. Have you had any issues at 8#? I have only dared to run 6# at low elevation and never any long pulls. I show 11.4-11.6 max.

 

[fbkakrdr]

Seems like an AFR of 12.5 is pushing it alittle. Have you had any issues at 8#? I have only dared to run 6# at low elevation and never any long pulls. I show 11.4-11.6 max.

No issues at all. At WOT the AFR is normally in the mid 11's the 12.5 normally shows at low to mid range. As far as long pulls go, the throttle plate that goes to my left hand throttle got bent and wedged my throttle pretty much wide open. I had my tether disconnected and the sled took off hit a tree and destroyed the left A ARM and bulkhead, then continued running in place at WOT on it's side until another rider could get over to it and shut it down, total time at WOT probably about a minute, with no engine issues.