Few mpi turbo questions

Studroes144

Studroes144

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Many know I did the stage 1 mpi turbo on my viper over the summer. Haven't had any snow yet to really get a feel for it but I have put a few miles on it the back field just playing around. First question, do the turbos come set from the factory to run a specific amount of boost, that's less that the full 6#s? I have aem boost and afr gauges on mine. Since the field right behind my place isn't very big it's only a matter of being able to hold it for 2-3 seconds before the edge of the field is coming really quickly. At most I've held it for 3 seconds, it usually only shows 2#s of boost on the gauge, this last time it did flash 3. Is it normal for them to be setup to run lower boost and then slowly adjust it up? Also the afr gauge when I first start the sled hangs right around 15. It quickly drops to about 14 then slowly goes down, by the time the warm up light goes off it's right around 11-11.5. Negative boost at idle is anywhere from 0 to -8. Just curious if that all sounds right for a starting point. As of now I have heavier weights in but still the same exact secondary setup as last year and she really has some life even at just 2#s. I did a clutch kit in my buddies cat 7000 which is all stock and that has no where near the feel the viper does. Getting anxious to ride!
 
Studroes144 said:
Many know I did the stage 1 mpi turbo on my viper over the summer. Haven't had any snow yet to really get a feel for it but I have put a few miles on it the back field just playing around. First question, do the turbos come set from the factory to run a specific amount of boost, that's less that the full 6#s? I have aem boost and afr gauges on mine. Since the field right behind my place isn't very big it's only a matter of being able to hold it for 2-3 seconds before the edge of the field is coming really quickly. At most I've held it for 3 seconds, it usually only shows 2#s of boost on the gauge, this last time it did flash 3. Is it normal for them to be setup to run lower boost and then slowly adjust it up? Also the afr gauge when I first start the sled hangs right around 15. It quickly drops to about 14 then slowly goes down, by the time the warm up light goes off it's right around 11-11.5. Negative boost at idle is anywhere from 0 to -8. Just curious if that all sounds right for a starting point. As of now I have heavier weights in but still the same exact secondary setup as last year and she really has some life even at just 2#s. I did a clutch kit in my buddies cat 7000 which is all stock and that has no where near the feel the viper does. Getting anxious to ride!
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I know when MPI sends them out there set at around 3-4 pounds. You will have to adjust that yourself, now that you have a gauge it's simple. But it shouldn't take that long to get boost. Mine was almost instant. AFR numbers at idle are going to run a little rich, but it's when you getting into it and WOT is what you want to set up correct. I thought D&D did all this for you. You said you had it dynoed and stuff??
 
No it hasn't been dynoed yet, hoping it can be yet this year but if not no big deal. They gave me a pretty basic run thru on the gems controller but also on a previous turbo build they did they said the gems was very very close with stock settings, just had to make one little change, so I really don't want to go changing too much yet as it should be pretty close. Once I hit full throttle there is zero lag, it is just only running 2 maybe 3 #s of boost, just wondering if that's normal. As far as lean afr's, what is getting close to the danger zone? Always kinda heard to keep it safe around 11.8 or mor
 
Studroes144 said:
No it hasn't been dynoed yet, hoping it can be yet this year but if not no big deal. They gave me a pretty basic run thru on the gems controller but also on a previous turbo build they did they said the gems was very very close with stock settings, just had to make one little change, so I really don't want to go changing too much yet as it should be pretty close. Once I hit full throttle there is zero lag, it is just only running 2 maybe 3 #s of boost, just wondering if that's normal. As far as lean afr's, what is getting close to the danger zone? Always kinda heard to keep it safe around 11.8 or mor
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Just curious, Is your kit intercooled, head shim? I thought the Stage 1 MPI kit was 4.5 psi boost and Stage 2 is 6 psi
 
Studroes144 said:
Innercooler, no head shim. The trail turbo yamaha offers is the 4.5 kit
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Good luck with it, should be fun. If you have a chance to put up some pics of your gauge installation that would be great.
 
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Studroes144 said:
For some reason I can't post up pics on here, but both gauges are mounted side by side right above the stock gauge, used just a universal mount kit with them
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OK, I've seen a few setups like that. Just like to see what other guys are doing . Wouldn't it have been nice if Yamaha had inputs on the factory cluster for AFR and boost? I'm sure It would be very simple to do.
 
I know OSP has a neat looking gauge setup. These universal mounts were just something on hand so we used them. With the gauges on top of the stock gauge it isn't much of a sleeper look, they're right out there in the open so anyone can see them but if u have a bigger windshield it would hide them nicely. I just figured if you're gonna spend the money on gauges and plan to keep track of them, mights well put them where u can easily see them
 
Studroes144 said:
I know OSP has a neat looking gauge setup. These universal mounts were just something on hand so we used them. With the gauges on top of the stock gauge it isn't much of a sleeper look, they're right out there in the open so anyone can see them but if u have a bigger windshield it would hide them nicely. I just figured if you're gonna spend the money on gauges and plan to keep track of them, mights well put them where u can easily see them
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Yup, I'm sure it wouldn't take long to melt a piston if it went lean or high on boost. Need to see that happen right away.
 
Studroes144 said:
For some reason I can't post up pics on here, but both gauges are mounted side by side right above the stock gauge, used just a universal mount kit with them
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Try the pics again. I couldnt post pics here either until a week ago now it works fine. Other wise use Tapatalk to load pics.

What you are seeing at warmup is your Idle Air Control Valve operating. It bypasses the throttle plates to give you idle. Normal to see those AFR's till it is closed.
 
Barry I had a similar thing happen on the MCXpress equipped Phazer I bought a couple years ago. Ended up putting a Mountain Max secondary clutch on it and solved all that. Seems the stock secondary shifted the sled up too quick caused the boost to lag. I know of some turbo guys that run a reverse dual angle helix to slow the upshift on take off and then accelerate the upshift. As I have not boosted my Viper yet I am going by other comparisons though. Maybe wind your secondary a lot tighter just for a quick test to see if this is an issue with yours?
 
Studroes144 said:
No it hasn't been dynoed yet, hoping it can be yet this year but if not no big deal. They gave me a pretty basic run thru on the gems controller but also on a previous turbo build they did they said the gems was very very close with stock settings, just had to make one little change, so I really don't want to go changing too much yet as it should be pretty close. Once I hit full throttle there is zero lag, it is just only running 2 maybe 3 #s of boost, just wondering if that's normal. As far as lean afr's, what is getting close to the danger zone? Always kinda heard to keep it safe around 11.8 or mor
Click to expand...

If you can't get to the dyno to set up I think I'd wait and try it as is on the trail or lake first. Your boost is probably normal for your elevation. Once you get some shakedown miles on it you could look to MPI to tweak the boost a bit. Also in my experience, you'll need heat and load to build boost. This should change when you get out on a lake and start to pull some wind/speed load.
 
stingray719 said:
Barry I had a similar thing happen on the MCXpress equipped Phazer I bought a couple years ago. Ended up putting a Mountain Max secondary clutch on it and solved all that. Seems the stock secondary shifted the sled up too quick caused the boost to lag. I know of some turbo guys that run a reverse dual angle helix to slow the upshift on take off and then accelerate the upshift. As I have not boosted my Viper yet I am going by other comparisons though. Maybe wind your secondary a lot tighter just for a quick test to see if this is an issue with yours?
Click to expand...

When I get on the throttle there is zero lag and it builds the 2-3#s of boost pretty much instantly, I'm assuming it's all just set low from mpi to start out safely at lower boost. Once the snow hits I'll be able to play more with it however I'd like to get it a little closer to 5#s of boost to start with since I'll be adding primary weight as I go too to keep it off the limiter. Just want to have it a little closer to full boost to start with so that I won't have to make so many clutch adjustments from adding boost slowly
 
Go ahead and shorten the waste gate rod a turn or two. Then run it again and check your boost. The nice thing with the Viper is that its easy to access the waste gate just by removing the one side panel.
 
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