Question about exhaust for 90Q

[90Q45blue]

I have a 90 Q45 with original exhaust. Well, after 246,000 miles I want new exhaust for the performance increase and better gas mileage. I was wondering if you guys had any insight/suggestions. I want a high quality muffler, exhaust system, etc that will give me high performance, much better gas mileage but I can't stand a loud and obnoxious exhuast. Quiet is good. Let me know what you recommend and where to get and how much. I would really appreciate it.

Nick

P.S. Fred, I was reading on your new car and your exhaust seems to be something I would be looking for. Do you know where they got it and how much it was? Thanks.

[maxnix]

Stock is the most effiecient for the amount of noise. A very loud one will net you 5-10hp, hardly noticeable.

Read the posts found by searching for exhaust and maybe headers. A ton of information.

[greg_atlanta]

I'm sure stock replacement is very expensive unless you can find complete system from junkyard. I think 90-95 are interchangable??

Best thing to do is shop around at local exhaust shops and see what they can do. From cats back is probably what you want.

I have a few loose baffles in my '92 Q (182K). I'd assume they're from the rear muffler, but hard to tell. Barely noticeable and I'm not interested in pricing out a fix since I have other priorities on fixing things!!

[Q45tech]

The 90-93 are exactly interchangeable, the 95-96 will require a short length of pipe to extend the passenger side and the flange moved forward 6-9" since the cats are a different design.

Why do you think that changing exhaust system will improve mileage? 5 HP might be possible with a very loud system but NO EXHAUST SYSTEM whatsoever wouldn't yield 10 HP!

[PalmerWMD]

The stock system is pretty good to begin with.Having said that as soon as I have my new car I will look at the records and let you know.

(remind me w/ an email).

Also we have a few good sponsors that sell exhausts, BRM for example.

Fred...

[90Q45blue]

Fred,

I went to their site and they didn't seem like they had exhaust systems for anything before the 97 Q.

Nick

[Q45tech]

Before you go spending money: drill and tap a port on the exhaust just past the second cat and measure the back pressure in psi!........or

"It is generally accepted by automotive engineers that for every inch of Hg of backpressure (that's Mercury - inches of Hg is a unit for measuring pressure) approximately 1-2 HP is lost depending on the displacement and efficiency of the engine, the combustion chamber design, etc".

http://www.thrashercharged.com....shtm

If you take the time to look you will see that the resonators are straight thru and so is the rear dual muffler assembly with a curve at the inlet where each pipe connects to an individual straight thru pipe to the rear.........no wonder the stainless system cost $1500 new to replace!

[90Q45blue]

Dennis,

Will do. Thanks for the advice and great article.

Nick

[911/Q45]

Has anyone ever had a Q exhaust system wear out?

[greg_atlanta]

Has anyone ever had a Q exhaust system wear out?

Mine is slighly worn... a few loose baffles in one of the mufflers. Had a few holes too but patched with metal tape. Also removed heat shields since they were rattling.

The $8 exhaust tips from Pep Boys make it looks like new again!

[AZhitman]

There's a guy who emailed me a while back who had a $1500 custom-tuned exhaust system made for his Q. Claimed 35 more hp in repeated dyno testing, but who knows. He wanted $1K for the whole deal - I passed.

I may still have the email address if anyone's interested.

[911/Q45]

If I spent $1500 on an exhaust system I'd claim 35hp too. More likely the gain is about the same as your Pep Boys tips!

[AZhitman]

You're probably right - Notice I didn't make the deal.

I will be replacing the rear resonator soon, however with a dual-in dual-out Ultraflow.