I've been noticing that my boost only gets to about 15psi @wot @high rpm. And like around 3k its's @12psi. That is like stage 2 pully boost.

I have a 2.79 inch.

Do you think my belt could be slipping? My boost gauge maybe messed up. I don't think I have a boost leak. I've never heard of anyone with a boost leak on these cars.

How would I know if I did anyway?

IDk Maybe my boost bypass valve is loose or something...

Any idea?

 

Aside from what you listed, very dirty airfilter possibly? Belt slip sounds like a good possibility too.

 

check out the how-to on the boost bypass mod it may answer your question, or even better check out all the threads on boost bypass and such, type: boost bypass mod into the search thingy!

 

did you change any of torque management settings for the supercharger in HPtuners? If you changed the % of boost in 2 gear it will affect boost in 2nd gear as well as 3rd, 4th and 5th.

 

No % in second gear is 200. Maybe I need to bring it higher. I may need to do the boost bypas mod.

I just changed the air filter but it was the same before. The only thing IA can think of is that I went to a catless DP and that would lower my boost, I just didn't think that much.

 

I was just going to ask you if you had changed anything on the intake or exhaust side. If you have the stage 2 belt you shouldn't be getting any belt slippage. Also, stage 2 makes 15psi peak with everything else being stock. So all your exhaust mods and your charge cooling mods would work to lower it.

Do you feel like your suffering from a loss of power somewhere? If not, then I don't think its a problem. You do want your psi to be as low as possible.

The boost bypass mod should never be mentioned. It goes back to the days before stage kits and HPT. If your car had a stage kit installed or a halfway decent HPT, then the boost bypass will get you nothing and possibly damage your car.

 

Yeah I feel like I'm not as fast. A stage 2 redline @ the track w/ a 3in pully was going 106's when I couldn't even get 105 MPh that night. My AFR is mid low 11's and I pull 23 degrees of timing. My only thought is my plugs are bad or I am not getting enough boost. Well I know my plugs are bad, the car idles very rough and I get a little spark blow out high in RPM but I didn't think it would suck MPH out.

 

Bad plugs can have a significant effect on performance. I would suggest spending the $8 (if your using copper) or $25 (if using iridium) and changing your plugs. While your at it, you can key your plugs so they are in line with your fuel injectors.

 

Yea because plugs and boost pressue in the manifold are definately directly related.

If other VE increasing bolt-ons lower your boost, you wouldn't feel any slower. You'd just be making the same power at less boost. It must be belt slip, the bypass, or a large boost leak.

 

What's the weather like there? If it's hot and muggy it's not going to boost as high as when it's cool out. Just my .02.

 

plugs have nothing to do with it.

you pulled the cat off correct?

IE, this is why.

don't freak, it's fine.

 

And it will feel slow. Excellent point.

 

I have a 2.6 pulley and right now Im only getting like 17-18 psi at the most and and thats becuase its sooo hott outside

 

Yea, and I said bad plugs will reduce his boost.

He said his plugs are bad, I said he needs to replace them. Didn't say anything about his plugs reducing his boost.

 

I have GM stage 2 installed and was getting 15psi. I just put in a K&N and I'm only getting about 12-1/2 to 13 now....is that normal, seems like the power is about the same, but I don't know if maybe adding the intake after the stage 2 reflash if it threw the AFR out of whack.

 

i was boosting 20psi before my header and catless downpipe and now its barely 18psi

 

Not to freak you out or anything but I have a stage 2 with the K&N and I still peak at 15.

 

That's all you did? I was going to say, adding a catless exhaust is definitely going to reduce your boost. Also, if I remember correctly I remember you saying your A/F was low 11's, that's a bit rich, so adding the intake would not have made you run lean...

If anything, the intake would have leaned you out in a good way, taking you more near 11.6-11.8.

As the above poster said though, definitely get your plugs taken care of... bad spark plugs won't affect your boost but they will sure as **** affect your motor, and bad/improperly gapped plugged are a common cause of detonation, especially on boosted applications!

 

I'm guessing its a combo of bad plugs and heat out that lowers my boost that is killing my performance. The problem is no one around here sell the plugs I use I have to order them, and its just a pain in the sack. Thanks for the input!!

 

You don't have an Advance Auto Parts out there?

 

I get my plugs from Murray's. Been there twice, and both times they asked me what car it was for, and told me the plugs DEFINITELY were not for my car (TR6's), and one guy almost didn't want to sell them to me LOL! Saying that if I used those on my car it would damage it right when I started it haha

I'm like... because your computer says so?

Damn auto parts store workers.... sigh.

 

high intake air temps after the blower will lower boost levels.

over 230 degrees is when it starts killing boost.

but well before that it, it kills timing.

 

Next time you go say you want to order part number ..... and then they won't even know.

 

Yeah they never carry the NGK Bkr7E. Not in stock anyway.

 

Order them then. Bad plugs in a boosted engine can lead to serious problems.