TurboMatt
Pro
Strange problem.
'07 Apex mtn. custom built kit using a impulse header, gt28rs turbo(internal wastegate), custom built intercooler & piping, Hallman pro rx boost controller 3 stacked stock head gaskets & arp studs.
Here's the deal. I live in WI, ie. low elevation. When I run the sled back home or in the U.P. the lowest I can get my boost is 12psi. This is with either the boost controller removed from the line to the wastegate(ie wastedgate line running str to the boost source) or with the boost controller setup and turned all the way out. 12psi is as low as it goes. I haven't tried to turn it up from there because I run it on pump gas and thats my limit.
When I ride out West, 9000+ft elevation: If I don't change anything from my settings back home sled will make about 6-7 out of the gate. If I put the heavy spring in the Hallman boost controller and crank it all the way down the absolute most I can get out of it is 10-11 psi sometimes, but usually it falls off to 8-9psi. This is with the boost controller cranked all the way in.
Is this normal? Doesn't seem like it to me.
Im my eyes it should make the same about of boost, its just the turbo will be spinning faster to do it.
I have done a boost leak test. It checks out good, no leaks. While doing the test I can verify that the wastegate actuator is working properly. It crack open at about 11psi and goes further from there. I have the actuator off the sled right now and test it in my hand, same thing, it seems to operate correctly without leaks.
What gives? Any idea?
'07 Apex mtn. custom built kit using a impulse header, gt28rs turbo(internal wastegate), custom built intercooler & piping, Hallman pro rx boost controller 3 stacked stock head gaskets & arp studs.
Here's the deal. I live in WI, ie. low elevation. When I run the sled back home or in the U.P. the lowest I can get my boost is 12psi. This is with either the boost controller removed from the line to the wastegate(ie wastedgate line running str to the boost source) or with the boost controller setup and turned all the way out. 12psi is as low as it goes. I haven't tried to turn it up from there because I run it on pump gas and thats my limit.
When I ride out West, 9000+ft elevation: If I don't change anything from my settings back home sled will make about 6-7 out of the gate. If I put the heavy spring in the Hallman boost controller and crank it all the way down the absolute most I can get out of it is 10-11 psi sometimes, but usually it falls off to 8-9psi. This is with the boost controller cranked all the way in.
Is this normal? Doesn't seem like it to me.
Im my eyes it should make the same about of boost, its just the turbo will be spinning faster to do it.
I have done a boost leak test. It checks out good, no leaks. While doing the test I can verify that the wastegate actuator is working properly. It crack open at about 11psi and goes further from there. I have the actuator off the sled right now and test it in my hand, same thing, it seems to operate correctly without leaks.
What gives? Any idea?
tapex_07
TY 4 Stroke Master
- Joined
- Feb 15, 2009
- Messages
- 1,160
- Country
- USA
- Snowmobile
- '10 Nytro MTX SE IMPULSE 174x3
'14 Viper XTX SE MPI 159x14x1.25
'07 Apex RTX SC2 MPI 128x1
Check for boost leaks around the throttle bodies. Lots of "T's" in there. And check for any leaks around the header for cracks or at the flanges.
I'm confused, do you want more or less. You always get less boost the higher elevation you go. Take the controller off and set your base boost with the waste gate rod. I set mine for 8, just incase i run into 87 octane only stations. I'm also using a 2 stage controller. Just a couple of turns and i'm back up to 14 LBS. Low boost and high boost. Is the intercooler lifting out of the boots. Start the sled and grab a can off carb cleaner and spray around intercooler, boots, tees, throttle bodies. If there is any change in idle, you have a leak. Is your header cracked? Header bolts backed off? Do you have a blow off valve? That could be opening letting off boost. This will keep you busy for awhile checking these scenario's. Good Luck
