Boost Pressure
Posting Guru
Joined: Feb 2004
Posts: 2,248
Likes: 1
From: Elverson, PA
Yea - I can definitely 2nd that the stock turbo doesn't like boost of more than 25! My stocker was toast before 30,000 miles! On a stock turbo - you really aren't accomplishing much, after your boost gets up so high - as you are getting way out of the usable range anyhow.....
Post Fiend
Joined: Feb 2007
Posts: 14,541
Likes: 2
From: Dallas-Ft. Worth
That's the first time I've ever heard of stock tuning driving a stock turbo over 25. I've heard of it getting close with the wastegate disconnected, like 22 or so, but never 25+. I don't know the early-birds too well, though either. You must have a boost fooler for the MAP sensor then. The PCM sets a code around 22-23, and defuels the engine at 25.
Postmaster
Joined: Oct 2005
Posts: 2,956
Likes: 0
From: Northeast TN
That's the first time I've ever heard of stock tuning driving a stock turbo over 25. I've heard of it getting close with the wastegate disconnected, like 22 or so, but never 25+. I don't know the early-birds too well, though either. You must have a boost fooler for the MAP sensor then. The PCM sets a code around 22-23, and defuels the engine at 25.
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Post Fiend
Joined: Feb 2007
Posts: 14,541
Likes: 2
From: Dallas-Ft. Worth
Yeah, I don't know if the early tuning had the defueling at 25psi or not. You will now, though!! And a CEL at 22 psi.... 
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Post Fiend
Joined: Dec 2002
Posts: 6,245
Likes: 1
From: IL, USA
That would be the speed limiter in the 90s.
Most chips will remove it....mine's gone.
Once you pass 25psi without some sort of overboost eliminator the engine will defuel and you'll get a Service Engine Soon light.
Most chips will remove it....mine's gone.
Once you pass 25psi without some sort of overboost eliminator the engine will defuel and you'll get a Service Engine Soon light.
Postmaster
Joined: Oct 2005
Posts: 2,956
Likes: 0
From: Northeast TN
It'll be OK. I've got a DIY boost fooler, ready to go in. I just need to make a bracket for it.
Postmaster
Joined: Oct 2005
Posts: 2,956
Likes: 0
From: Northeast TN
. I've hit 25psi several times and 28-29 a few times while towing. Although when I've hit these numbers it's been brief due to egt's.
Postmaster
Joined: Oct 2005
Posts: 2,956
Likes: 0
From: Northeast TN
I don't know. It's an autometer ultralite. I'll try it tomorrow and see if it will set a SES. I haven't had a chance to get on it since I swapped pcm's. I do know that before I disconnected the red line. I would hit 15# at wot. I disconnected the line and it went to 18#. After I cleaned and painted the IC pipes I could hit 22#. And now that winter is here it reads 25#. How could I check my gauge? Maybe with a compressor and a regulator?