Boost Problems

[mr_man]

A couple days ago I had a 3" mandrel bent catback with no mufflers and no resonators installed on my car. It was rainy the day I had it installed, so couldn't do much testing.

The next day it was nice and decided to test out how it affect my boost. I launched at 3/4 throttle from a stop till I stopped spinning then WOT, I hit 14.3 psi in 1st gear (previous best was 11.1 in 1st) shifted into 2nd gear, and hit 17.2 PSI (previous best was 13.3) in 2nd gear with almost 1,000 RPMS to go, car started chugging a little so I let off. Got home and thought something smelt a little funny, so I popped my hood....part of the front exhaust manifold was glowing red. The way my PSI was climbing, I probably could have hit close to 19 PSI.

Earlier that day, the first time I've been able to go WOT since I've had my exhaust, at the top of first I heard a "pht pht pht" sound and then promptly let off the gas. The sound didn't sound mechanical or metalic, just kinda different. Popped the hood then and didn't notice anything out of the ordinary.

I'm less worried about the manifold glowing as that is probably a result of running too much boost. What I want to know is how did my boost go up so much? The temperature was in the low 30's, is it possible that that is what my boost should be? It seems a much too high for my mods.

I did make a post on ClubGP, and it's been suggested that my exhaust is getting blocked somehow. I looked at the exhaust piping and there are no abnormal kinks, which leaves my cat. What would it take to clog a cat in under 20,000 miles? I'm thinking I may have a problem with my boost-bypass valvle. Any idea's?

[Turbo V6 Camaro]

17 PSI ON STOCK MOTOR !!!!!!!!!!!!!!!! :eek: :eek: :eek: [img]graemlins/omg.gif[/img]
the pht pht pht you heard was "PING" it had to be theres no way you wasn't KR'ing it up

there no way the 3inch pipe will do that unles it blcoked it has to be you cat doing it, and yes they have been know to plug that soon also..... and having boost is adding extra fuel and at 17 PSI :eek: your locking up your injectors and i bet it fried the cat, and your goint to hurt your motor if your not care full !!!

[Wicked 3800 V6]

Ummm ... I wouldn't be boosting like that unless you 'd like a new motor. "Hitting high boost" shouldn't be your goal! Yikes!

[mr_man]

Originally posted by viper04af:
17 PSI ON STOCK MOTOR !!!!!!!!!!!!!!!! :eek: :eek: :eek: [img]graemlins/omg.gif[/img]
the pht pht pht you heard was "PING" it had to be theres no way you wasn't KR'ing it up

there no way the 3inch pipe will do that unles it blcoked it has to be you cat doing it, and yes they have been know to plug that soon also..... and having boost is adding extra fuel and at 17 PSI :eek: your locking up your injectors and i bet it fried the cat, and your goint to hurt your motor if your not care full !!!

I didn't purposefully hit 17 psi, I was shocked I did as well. I had my car scanned before the exhaust, the injectors were borderline static, and mass air flow was also almost maxed out.

I have been avoiding going WOT, I'll take it in to my exhaust shop on Monday.

Ummm ... I wouldn't be boosting like that unless you 'd like a new motor. "Hitting high boost" shouldn't be your goal! Yikes!

It wasn't, I was happy with the 12.5 - 13.2 I was getting, but wanted bigger exhaust to get get rid of my KR, then went to test it out, and then 17+ psi :eek:

Thanks for the replies. Is there anything else it could be besides plugged up exhaust?

[GN-T66]

Many people have blown cats in way less than 20,000 miles. lightly tap the outside of the cat when it's cooled off and see if you can hear anything rattling around inside.

[phoenix64]

With a supercharger the boost should go down with a new exhaust. Less restriction, and it would be flowing the same amount of air.

[Turbo V6 Camaro]

Originally posted by phoenix64:
With a supercharger the boost should go down with a new exhaust. Less restriction, and it would be flowing the same amount of air.

not alwys true Shirl could only hit like 3 PSI till she put on a better exuast

[AlienInv8r]

Originally posted by Wicked 3800 V6:
Ummm ... I wouldn't be boosting like that unless you 'd like a new motor. "Hitting high boost" shouldn't be your goal! Yikes!

In his sig it does say he has a GTP, the L67 can handle that alright I'd assume, correct? Just in case any of you all missed reading that.

[Turbo V6 Camaro]

Originally posted by AlienInv8r:
</font><blockquote>quote:</font><hr />Originally posted by Wicked 3800 V6:
Ummm ... I wouldn't be boosting like that unless you 'd like a new motor. "Hitting high boost" shouldn't be your goal! Yikes!

In his sig it does say he has a GTP, the L67 can handle that alright I'd assume, correct? Just in case any of you all missed reading that. </font>[/QUOTE]not on stock tuning you can't and with astock cam too!!! ouch

[mr_man]

Originally posted by viper04af:
</font><blockquote>quote:</font><hr />Originally posted by AlienInv8r:
</font><blockquote>quote:</font><hr />Originally posted by Wicked 3800 V6:
Ummm ... I wouldn't be boosting like that unless you 'd like a new motor. "Hitting high boost" shouldn't be your goal! Yikes!

In his sig it does say he has a GTP, the L67 can handle that alright I'd assume, correct? Just in case any of you all missed reading that. </font>[/QUOTE]not on stock tuning you can't and with astock cam too!!! ouch </font>[/QUOTE]Injectors and MAF are maxed out between 13 and 14 psi, so at 17 I was running EXTREMELY lean. Had the car up today, there's a nice kink in the stock exhaust just past my cat, I think that is the problem, just gives me an excuse to get a bigger downpipe [img]smile.gif[/img]

And also, I have an L32 not L67 :cool: .

[phoenix64]

Actually in this case, would you be running lean? Your not flowing anymore air. Just increasing pressure.