My car has been tuned for the last 36k miles and has been running like a champ up until the last 3,000-5,000 miles or so. Sometimes the car would take off like it normally does and other times it would be sluggish...more so than ever recently. I was kinda thinking it was heat related since it's been in the 90 degree range for the last few weeks but I knew something just wasn't right. Last night I went out for a long cruise and took notes on what the car was doing...it wasn't holding boost like normal.

My car is HP tuned, full bolt-on, and meth running around 28psi on the dyno and it will see 26psi going through the gears. Last night a 3rd gear pull from 60mph saw 27psi..drop to 22, back up to 25, down to 20, and back up to 21 by 6200rpm in third. So boost was all over the place just from a one gear pull. On the dyno 6 months back it would hold boost solid and slowly drop with rpm as a small turbo car normally does. A 4th gear pull from 85mph showed the same results with even worse boost fluctuation.

After alot of research on here I started to lean towards the factory bypass not holding the boost. I looked into the Forge bypass and how it works and started tinkering around with the car today. I took the factory bypass apart and placed a 1/4 spacer in there to make the spring have alittle more tension....

Well wouldn't you know that fixed my boost issues. The car is back to frying the tires from a 2nd gear roll and has zero issues holding boost like it use to. It's seeing 24psi in 2nd vs 20psi it was getting yesterday. A 60mph roll showed 27psi and a slow drop to 21psi at 6200rpm.

The spacer in the stock bypass is just a temp fix as i'm ordering the Forge bypass in about 5 minutes. I know alot of people are running the Forge but I never looked into it until now. Either the spring is weak in my car or the diaphram isn't holding...

Hope this helps anyone that comes across the same issues.

Andrew

 

hmm nice riggin idea lol

 

So the tension of the spring was the culprit?

 

I'd say so since the spacer fixed the issue. The diaphram appears to be in good shape.

 

Hmm, a little to much boost for the stocker?

 

Since you are HP Tuned, there are tables for the BPV now. Try running the GMS1 settings and see if that also helps!

 

Thanks for the heads up! I'll def look into that.