boost problems, now gauge reads too much boost, but car feels slow
10-13-2014, 04:08 PM
#1
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boost problems, now gauge reads too much boost, but car feels slow
Starting to troubleshoot why my car isn't boosting properly. it's an 86 turbo
When I first got it, it would boost about 15psi but it all came at once at 4k RPM, it felt very NA until 4k+. It shows 10psi at 3k~ish rpm but doesn't feel quick at all. PO stated car should be boosting 15-16 psi.
Then it started to cut off at higher RPM, almost like over boost protection. I would hear a loud whoosh of escaping air, so I did a cursory check of boost leaks. I had no method to really test, so I just tightened things down. It looks like one of the clamps from the IC to TB was loosish, so I tightened that, and I redid a clamp on the hose that comes off that hard pipe as it looked like it wasn't sealed well.
That stopped the shutoff and the car ran better, but 2500-4000 was still useless. Shop that recently worked on my car also noted that 2500-4000rpm should feel stronger. Then just yesterday I noticed that it was hitting 20+ psi at 4500 RPM. Which is way more then it should. Could something be causing the gauge to read too high, or am I somehow over boosting? I'm not getting any OBP though.
Any tips on what to look for first? I was going to start with a proper boost leak test. But what could cause it to boost 20psi? Or is it a false signal?
Mods:
chipped, apparently some detuned version of a turbo cup car tune
stock WG shimmed
LR Boost Enhancer
K26/8
new bypass valve (updated)
All new boost hoses and clamps from LR with venturi delete
Adjustable FPR set to 3bar
stock intake
Thanks in advance!
When I first got it, it would boost about 15psi but it all came at once at 4k RPM, it felt very NA until 4k+. It shows 10psi at 3k~ish rpm but doesn't feel quick at all. PO stated car should be boosting 15-16 psi.
Then it started to cut off at higher RPM, almost like over boost protection. I would hear a loud whoosh of escaping air, so I did a cursory check of boost leaks. I had no method to really test, so I just tightened things down. It looks like one of the clamps from the IC to TB was loosish, so I tightened that, and I redid a clamp on the hose that comes off that hard pipe as it looked like it wasn't sealed well.
That stopped the shutoff and the car ran better, but 2500-4000 was still useless. Shop that recently worked on my car also noted that 2500-4000rpm should feel stronger. Then just yesterday I noticed that it was hitting 20+ psi at 4500 RPM. Which is way more then it should. Could something be causing the gauge to read too high, or am I somehow over boosting? I'm not getting any OBP though.
Any tips on what to look for first? I was going to start with a proper boost leak test. But what could cause it to boost 20psi? Or is it a false signal?
Mods:
chipped, apparently some detuned version of a turbo cup car tune
stock WG shimmed
LR Boost Enhancer
K26/8
new bypass valve (updated)
All new boost hoses and clamps from LR with venturi delete
Adjustable FPR set to 3bar
stock intake
Thanks in advance!
Last edited by kem; 10-13-2014 at 06:41 PM. Reason: edit
10-13-2014, 06:36 PM
#4
Burning Brakes
I'm not into mods myself, but why the 3 bar FPR? - seems to me that you may be over-fueling a stock engine, - WideBand O2 would be nice to have to sort that. Over Boost would be a WasteGate [shimmed too much?]/Cycling [Timed] Valve/Boost Controller[which you don't have] thing. ... far as I know.