rcraceshop

I am looking to upgrade my 1991 coupe.

As I know performance and inexpensive do not work in the same sentence.
I do have a limited budget but I can sneak some parts in once in a while

I was looking at Corvette Central and found these items

http://www.parts123.com/parts123/yb....Z5Z5Z50000050f

http://www.parts123.com/parts123/yb....Z5Z5Z50000050f

I also have some Borla mufflers i can install if the exhaust is too loud with the eliminators.

Not sure if these are the exact ones but they look very close

http://www.borla.com/products/corv_c...rt__11579.html

Has anyone used these products?

Would it be a waste of money?

What would be the pros and cons of these products

Thank you

Scott

ovrebo1

Best bang for your buck is to give your car a thorough tune up, clean the throttle body, maybe run a tank of injector cleaner, clean your windshield......

John A. Marker

You can cut out the louvers on your air cleaner cover for nothing. It will not add much in the way of HP....but a small amount. No need to buy a new cover that is already cut out.

Take a look at Vader86's home page.

Silver96ce

I wouldn't waste the time with the air cleaner lid or cut your stock one either. ZR1's used essentially the same air filter intake system and they ranged from 385 to 405 horsepower. So unless you have drastically increased hp, you're wasting time and/or money.

Mufflers will change the sound but until you deal with the rest of the restrictive exhaust system, you're not going to gain really much of anything until you address from the stock exhaust manifolds back (lt headers, etc.).

If you haven't already gone through the engine and drivetrain, do as Overbo1 suggests, a thorough tune up and I would add a complete maintenance including hoses, vacuum hoses, trans service, brake flush and new brake hoses if original - maybe upgrade to braided - that's a worthwhile performance upgrade.

If you have an auto - check and see what rear gears you have. If 2.59/2.73 an upgrade to 3.07 will provide probably the best bang for the buck upgrade. Otherwise performance costs money and there are no cheap, easy, reliable performance upgrades. Reliable horsepower upgrades cost money.

antfarmer2

Don't forget the o2's part of maintenance most ignore. They get old and slow with no code big differance

rcraceshop

Thanks guys!!

This being my first Corvette I am learning more every day about the do's and donts of owning one and I really do appreciate all of your input.

The car has 71000 mi and seems to run great.(It will usually roast the tires thru 1st and kick sideways into 2nd )

The guy that owned it before me seemed to take very good care of it.

I just did a radiator flush and will be changing the trans filter and having the diff serviced next week.

The main reason for the exhaust change is I would like it a bit louder and I have a bit of a rattle at low rpm. (I think coming from the passenger side front cat or manifold heat shield ) and from reading threads on here the 91 main cat is very restrictive.

I think if I was to try to build for horsepower I would be better off getting a 92 or newer Vette or just changing the whole motor but that would have to wait until next summer.

So for this car I would like to do some low dollar add on's while fixing the few issues I have and try to keep it mostly stock yet sneek in a few hp.
Sure I would love to buy a Corsa or magnaflow exhaust and some nice headers but that costs almost half of what I paid for this car.

Thank you all
Scott

vader86

Not a lot you can do on a tight budget, but the little things are there. Even together they do not add very much power.

If you want mods, come up with a plan and stick to your plan. Do as much at a time as you can.

rcraceshop

Thanks Vader your page is where I got the ideas about the restrictive cats and k&n filter

I just figured this exhaust would flow better than the stock and i always liked k&n products and seen one with the cut air lid.

Again I am not expecting miracles.



Thank you
Scott

John A. Marker

I am not sure how restricting the 91 exhaust really is. My 85 was choked for sure. My 95 with the cats and Magnaflow mufflers has zero back pressure.

rcraceshop

From what I have read the 91 and earlier cats are much more restrictive than 92 and up

QCVette

Like everyone said, they won't add much power, if any.

However the sound can be changed quite a bit. I used the muffler eliminators on a '94 LT1 and it is quite loud. I had that car for about 45k miles and it grew on me to where I really like the sound. I miss it now. It has a nice deep rumble at idle and is obnoxious loud when you hit the gas. You can do a lot to control the noise with the throttle.

I currently have a Corsa full exhaust on my '95 and a Borla full exhaust on my '96. To me they are both way to quiet.

There is a different style of Borla (S-type) that I heard on a '90 and it sounds good.

For a low budget mod, the eliminators make it sound a lot different and would be the one I would try.

You should go to some local Corvette clubs or other events and try to listen to a few. Sound is so subjective that you need to find one that you like.

Good luck.

rcraceshop

My other option would be this exhaust

http://www.ebay.com/itm/86-91-Corvette-C4-Pypes-Exhaust-2-5-Crossmember-Back-L98-System-SCC40R-/121227673181?hash=item1c39bb7e5d&vxp=mtr
But then I would need to figure out what kind of headers to get and that option would be close to 3 times the price.

rcraceshop

Thank you QC.

I do like them loud also and was thinking of just the eliminators then I read about the restrictive cats on the 91 and earlier cars and seen the exhaust in the first thread I posted and that looked like a affordable solution.

I do think it will be quite loud with full open exhaust.

I have some Borla mufflers I could put on if i needed to tone it down a bit.

c4cruiser

You may find that headers and a true dual exhaust system may not cost that much. Hedman has painted headers that you can get thru Summit Racing for under $200. Their creamic coated versions run about $350. Hedman has versions for keeping your AIR system or not keeping it. These can be installed by yourself if you have a way to get the car about 30" off the ground.

A good muffler shop can build some true duals for probably a couple hundred more. They can also add a bung in the header reducer for the O2 sensor so it can be hooked up and it will still work properly. Have them add an X-pipe to help with noise.

Now if you live in an area where you have to have the car emissions tested, you will have to keep the cat. If not, it can be removed. But a shop will typically not remove a working catalytic converter as there are some stiff federal fines if they get caught (5 figures!!). What you could do is to remove the existing exhaust system and install the headers. Then remove the license plates. Trailer the car to an exhaust shop and tell them the car is for "off-road use only". That should make them feel better about installing true duals. You can use mufflers of your choice.

rcraceshop

Has anyone on here used Hedman headers?

A friend of mine suggested them also but i have read on a post in here to stay away from Hedman.

I really do want headers and would definitely want the ones that wont rust as soon as i turn it on.

I live in Wisconsin and will be getting collector or hobby plates soon mainly so i don't have to pay to register it each year.
I had to get the regulars because the collector or hobby plates take up to 2 months to receive. They don't do temp plates anymore and I really wanted to drive it so i will get them before next registration.
I don't even think WI tests cars over 20 years old anyway.

That being said i am not against a high flow converter I would prefer to have one but my math says about $200+ for the Y pipe $200+ for the cat and $800+ for a cat back system plus the price of the headers.

Not to mention there are so many different manufactures out there and I don't know what works and what doesn't.

Thank you
Scott

aklim

It inst as sexy but dump fluids, change filters. Also get the pump out and see if the sock is clean and check for debris in the sump that they have. After all that, change plugs, cap, rotor, wires.

If you have stock Multec fuel injectors, get rebuilt ones from FIC and toss the stock ones in the trash.

Get new gaskets for the throttle body. Remove it, remove the IAC housing and the IAC, clean thoroughly with brake cleaner, reinstall.

Buy yourself a Factor Shop Manual and a scanner that can read data from the ECM and not just a code reader.

rcraceshop

When I got the car he just replaced the injectors .(not sure what brand)
I will be doing the trans filter and diff next week.
Im gonna wait until i do the brakes to do the brake fluid flush .
I will be also doing the cap, rotor, and wires soon they look to be newer but oem.
The car runs very well.
The reason I want to do the exhaust is I have a rattle up by the passenger front (im guessing front cat heat shield) Also I would like to give it a little more rumble in the prosess
Once winter comes I will be doing alot more to it as I will have much more time and a fatter wallet.

rcraceshop

You are not to far from me Aklim.

Do you go to any car shows around here?

They have them almost every day by me.

fast.asleep

This is probably the best piece of advice he can give you. I tried all the budget junk and a lot of it was a waste of money. Bookmark his site and reference it often.

Plan what kind of car you want to end up with and start hording. I bought one or two pieces a year and came across some great deals in the process. I installed what I could along the way and paid someone to do the rest. It didn't hurt the wallet too much since the cost was spread out over years. it still needs a few things (torque converter, brake upgrade etc) but I'm happy I did it this way

rcraceshop

Has anyone used these?

http://www.ebay.com/itm/OBX-SS-Exhaust-Manifold-Headers-w-Y-Pipe-85-91-Chevy-Corvette-5-7L-V8-L98-NEW-/201329019083?fits=Year%3A1991%7CModel%3ACorvette&hash=item2ee02508cb&vxp=mtr
http://www.ebay.com/itm/OBX-Stainless-Steel-304-Catback-Exhaust-Fits-1986-1991-Corvette-C4-5-7L-/111697603064?fits=Year%3A1991%7CModel%3ACorvette&hash=item1a01b229f8&vxp=mtr