new lt headers and ory pipe installed, made car slower?

[jackmajic]

I just had my old mac shorty headers, y pipe and hi flow cats removed, because they were damaged and 11 years old. They were replaced with hooker lt headers and an off road y pipe, but i kept the slp cat back because they said there was nothing wrong with it. The car sounds good, louder but feels sluggish and cant even chirp the tires in 2nd gear anymore. I know it feels definitely slower after driving it for the last 12 years. Any ideas? Also yes it was given a tune to compensate for the ory. Fyi I have a 1999 trans am convertible.

[Knight]

How was it tuned?

[jackmajic]

not exactly sure. i had it tuned 11 yrs ago by a guy named ed wright with my old setup and it was perfect. this time is was done at a shop in schaumburg il called speed inc. as far as i know they didnt touch my old settings, just turned off the 02sensors.

[cammed goat]

Are your new headers larger than the old ones? Like, are the individual tubes larger in diameter than the ones on the old headers? Also, when was the last time you cleaned the MAF sensor? No two header systems are alike. If it's bogging, then another tune is in order. Maybe a more thorough tune as well.

[Knight]

It's possible the new tune is causing your problem. There are a few things you could check though. Did you install new O2s with the exhaust? If so, did you use harness extensions or splice the wiring?

You could also try cleaning the MAF with some CRC cleaner. Has the fuel filter been changed recently? You could check the fuel pressure at the rail - you should have 58 psi. You could also have the car scanned for any pending codes.

[jackmajic]

Cammed - the header systems are the same size 1 3/4", but i just looked at the invoice and they gave me headers for the 00-02 and my car is a 99 which from hooker they are supposed to be different.

Knight - since i wasnt charged for new o2 sensors i have to believe they are the same ones.

Cammed and Knight - on your advice i cleaned the maf (dirty) and throttle body(filthy) and changed the fuel filter for good measure.

I can feel that those definitely helped in the smoothness of the engine, runs very good, and im thankful for your suggestions they definitely improved the ride. I still say there is something wrong with the tune. The shifts are not nearly as hard as they used to be in fact it feels like it did when it was bone stock. Im not sure if getting the wrong headers would make a huge difference too. Thanks again for your help.

[Knight]

If the O2 sensors are the stock ones, and they used extensions, or even worse and spliced them, that could be causing problems. The ideal setup is a set of Bosch 13111s. They have a wire harness long enough to reach the factory plugs.

It's going to be a little hard to pinpoint, but we'll try to help out as best we can.

[cammed goat]

I would HOPE that shop didn't splice the O2 wires. To me, that is just shoddy.

[Knight]

I would HOPE that shop didn't splice the O2 wires. To me, that is just shoddy.

I agree.....but you never know, Rich. I'm sure you could tell some stories about stuff you've seen done......

[cammed goat]

I haven't seen spliced O2 wires...yet.

[Lunatikgixxer]

Do you have any SES lights on? If you do see which code(s) youre throwing.

[Knight]

I haven't seen spliced O2 wires...yet.

I have. It isn't pretty. Doesn't work too well either.

[jackmajic]

No SES lights and not throwing any codes. Talking to the manager he says the year of the headers doesnt matter. Would I be able to look at the 02 's and tell what was done?

[Knight]

No SES lights and not throwing any codes. Talking to the manager he says the year of the headers doesnt matter. Would I be able to look at the 02 's and tell what was done?

You should. Trace the wiring off the sensors back to the connectors. There should only be one set of connectors for each O2. If extensions were used, there will be two. It should be very obvious if they're spliced.

[jackmajic]

No splicing. The work seems very neat. The programmer states that as soon as he plugged in he saw that the rear 02's had been deleted and a tune had been previously done so he stopped there. Thats why I was not charged for a tune. The shop says that the old tune should result in a 10hp loss at best but cant believe that I could even tell. It is running very smoothly with your suggestions but I really dont want to spend a ton of money on specialty tunes and dynos because the shop isnt going to give me anything else.
The original tune was done with my old setup : mac midlength(not shortys as I thought)headers and random tech hi flow cats. New setup: hooker long tubes and off road y pipe.
Would another tune make much difference in your guys opinion or should I just let it go? PS I never have taken it to the track and my little street races are way in the past.

[Knight]

You could contact Frost - he's a member and sponser on the site. He does mail order tunes, and is very highly recommended. He's very reasonably priced too - $150 if you only have bolt ons. He may be able to answer some questions and help you out.

[cammed goat]

Knight is correct. Get yourself some more "oomph" with that new setup you have.

[jackmajic]

Sounds like a plan. Thanks again for your help.

[jackmajic]

Sounds like a plan. Thanks again for your help.

[jackmajic]

Sounds like a plan. Thank you both for your help.