What is the max boost pressure you can get out of a stock turbo and would a boost controller kit help?

 

Stock tuning? 17-18 psi or so.

Aftermarket tuning 25-30psi+ is common. Stock turbo does not like more than 25psi and extended times above 25psi will shorten it's lifespan.

 

I have got 30+ boost on my stock turbo with my tuning. I get a little more now with my mods. Like DC said, 25# is the most that the stock turbo likes to see.

 

Wow, I must be doing something right! I can hit 25psi with no tuning, and my stock early bird turbo. With 9-10k behind me, I can 28-29psi just before my egt's hit 1,000.

 

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.....

 

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.

 

The only time that I notice mine defueling is around 92-93 mph. Then, it falls on it's face. I haven't got a CEL either. But.. This info is all with the stock XLE4 PCM. It may be a different story now with the PMT2? I installed the pmt2 Wednesday, and this morning it was 32*. This was the first time I've ever heard the ebpv close. I've started my truck when it's been in the 20's, with the xle4 and the ebpv never closed. Who knows? BTW. I do have the wastegate disconnected, but no boost fooler, yet.

 

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....

 

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.

 

It'll be OK. I've got a DIY boost fooler, ready to go in. I just need to make a bracket for it.

 

Ive never got a SES. 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.

 

Where is your boost reading coming from? MAP line?

 

Yes it's in the map line.

 

I'll be honest -- I think your gauge is reading about 5 psi high (or more)...

 

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?