Questions About Viper's and Boost Kits

[LBZ]

I was reading up about the MPI kit for the MTX Viper and it said for 6000' + elevation. Also available is a below 6000' trail kit. Most of my riding is between 4500 and 6500' so it brings up some questions.

So what happens if I do ride it at or below 6000'?
Would a guy be better getting the trail kit in my case?
What's the difference between the two?
Is this 6000' thing common with all turbo kits?
Does it have something to do with the mapping in the ecm and MPI's controller they use which is why they say this?

I've never heard of this by any other turbo manufacturer's which is why I ask.

 

[Clode]

trail kits run less boost at the lower elevations (example a mcx 190 kit runs 4-5psi at sea level, 8-9psi at 6500ft), I would never buy a 190 kit, I would go to a min 240, and just turn the boost down for lower elevations, it is cheaper to buy a better kit initially than upgrade a base kit....Boost-it would be my first choice and MCX second

 

[bigfish]

this has always been a mpi thing,they seem to play way too the safe side with there recommendations,it is all about the lbs of boost & type of fuel you run + compression stock or headshim.if you run under 4500ft you just run less boost,iam another boost-it guy here,it will cost more but you get better components & some of the best customer service out there.there is nothing wrong with the mpi kit,its a good kit for the cost.

 

[LBZ]

What would happen if one didn't dial the boost down riding at lower elevation?
Also how do most kits adjust the boost these days? By adjusting the wastegate?

 

[Clode]

What would happen if one didn't dial the boost down riding at lower elevation?
Also how do most kits adjust the boost these days? By adjusting the wastegate?

detonation can occur if you don't dial it back a bit........the MCX kit has a self adjusting wastegate set-up that has its own issues, or a boost T is installed in the wastegate reference line, a lower PSI wastegate actuator is used to control the base boost setting (say 10psi) and the boost T is adjusted to bleed off a small amount of the pressure in the wastegate reference line to delay the wastegate opening raising the boost pressure. These are more reliable, I run a one on my turbo. You can go to a fancy electronic boost gauge that has a high/low setting and you choose which to use, I don't know these stand up in the cold conditions.

 

[LennyR]

Were there enough changes from 14 to 15 to warrant buying a 15 and starting from scratch as opposed to buying a low miles well done 14 if the price is attractive ?

 

[06yamahaapex]

Were there enough changes from 14 to 15 to warrant buying a 15 and starting from scratch as opposed to buying a low miles well done 14 if the price is attractive ?

15s have the updated oil tank so that the low oil light doesn't come on during a steep climb and the vertical steering post. The rear suspension geometry is a bit different on the 15s to get some weight off the skis.