Boost falling with MBC?
Originally Posted by Warrtalon
Have you verified this with a MAP sensor that logs your boost through an entire 3rd gear pull? Most people just look at their gauge and make boost claims, but this is actual proof through a MAP sensor. If you have such a log, post it up.
yes a friend and i logged thru his pocket logger, 19psi by red line but it wa sin 4th gear, and i am flowing 38lbs of air, which is pretty good i think.
but i do have that weird boost spike between 3400 and 4000 that has been mentioned in an other thread.
Originally Posted by GTKage
yes a friend and i logged thru his pocket logger, 19psi by red line but it wa sin 4th gear, and i am flowing 38lbs of air, which is pretty good i think.
but i do have that weird boost spike between 3400 and 4000 that has been mentioned in an other thread.
but i do have that weird boost spike between 3400 and 4000 that has been mentioned in an other thread.
So, your friend has a pocketlogger that has a MAP sensor input? I gotta find me something like that. Most pocketloggers wouldn't have a clue what boost you're running. Fwiw, when Al did my first road tune back when I was on basic mods, my boost spiked to 22.1psi and was still at 19psi by 7500rpm. It only dropped to 18.2psi by 8000rpm and leveled out. I don't know how it was in 4th. Then, with alky and the new mods, it spiked to just over 26psi at 3700rpm and was 22.5psi at 7000rpm.
Originally Posted by matt55
The main 3 things I can think of to help boost from falling off is...
1 Leaks , but you said that you and Warr checked for leaks already , (Iam so proud that you checked 1st)
2 mbc ( soft spring?)
3 pre-loading the WGA
Warr is a pretty knowledgeable guy so iam sure what ever we can come up with he has prob all ready told you to try .
From what ive seen on my car is a 22 peak and droping to 20-21 . This is with a SW gauge and me looking/driving so take it for what its worth.
1 Leaks , but you said that you and Warr checked for leaks already , (Iam so proud that you checked 1st)
2 mbc ( soft spring?)
3 pre-loading the WGA
Warr is a pretty knowledgeable guy so iam sure what ever we can come up with he has prob all ready told you to try .
From what ive seen on my car is a 22 peak and droping to 20-21 . This is with a SW gauge and me looking/driving so take it for what its worth.
2. I'm running the TurboSmart right now until until the first working Forge or Hallman unit makes it way to my local shop (should be by Friday). Does the turbosmart have different springs? I am able to reach the correct target boost peak at around 21-22 psi ... it's just tapering too much. Al seems to think that the TurboSmart doesn't hold boost as well as the Forge and Hallman ...
3. I keep talking about trying to tighten my stock WGA, but most people think I'm nuts
. If the Forge/Hallman doesn't hold 18-19psi at redline, I will certainly try tightening the turnbuckle on the WGA.Thanks!
Originally Posted by joshd
1 Does the turbosmart have different springs?
Its so strange that EVO's often experience this "tapered boost" problem. DSM's have the exact opposite problem usually, "boost spikes" where the pressure increases with rpms.
Update to this ... I purchased a used Hallman from a dcevoclub.com member and replaced the turbosmart loaner. Boost holds better with the Hallman, probably 2psi more at redline (in the high 17s if I had to guess) from what I can observe while driving.
I'd still like to tighten the WGA a bit to see if that helps, but I need a TBE first anyway, and the reduced backpressure will probably help ...
I'd still like to tighten the WGA a bit to see if that helps, but I need a TBE first anyway, and the reduced backpressure will probably help ...
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