Cat-Back or Hiflo cat and muffler???

[Mangod00]

I am the proud new owner of a 1996 LT-1 Corvette. It is currently stock and is sitting in the garage waiting for the nice weather. I have been reading the forums trying to decide what the first mod should be. I have decided on making the car sound nicer with a little performance to boot. I will be changing the air filter to a K&N air filter. I have read the forums on exhausts and seen a wide range. I am still undecided on what brand will give me a nice "burble" without attracting every cop in the neighbourhood. Also value plays a part in this so what is the best value in a muffler? So here are my questions and any insight would be well appreciated:

1) Is a cat back system the right way to go or will I get equivalent power and sound gains from a free-flow catalytic converter with only changing the mufflers?

2)Is the extra money worth paying for a more expensive exhaust, ie. Borla/Corsa over Flowmaster (about a $500 Canadian difference in price)?

3)Do the Hypertech programmers really work?

4)Should I change the thermostat as well?

Any insights will be well appreciated.

 

[c4cruiser]

There are a variety of cat-back exhaust selections to choose from. I have 3' B&B Tri-Flo's on my 92 but you'll find them pretty expensive ($1100 US). Nice sound but a lot of interior resonance. The polished stainless steel looks nice when it's kept clean. Borla is another expensive system but IMHO, it has more of a European sound rather than a muscle car sound to it. Flowmaster are probably reasonable but the one's I have heard do have some interior resonance.

Corsa make a very nice system and it is even a GM-approved part and available from GM dealers. Some of the vendors will have good deals on them. I think they run about $900 US. So my answer to your first question is yes it's worth it to spend the extra, but you should try to listen to as many systems as you can before installing something you may not like.

2. Replacing the OEM cats with high flow versions may not free up a lot of HP. US regulations technically do not allow cat replacement unless something is wrong with the factory piece(s). You would have to check Canadian regs to see what you can do here. The GM cats probably flow quite well and you may not see a big difference for the money involved.

3. Not really. They can change shift points in an auto tranny and change when the coolong fans come on, but unless you are going to be making engine mods (cam, head work, etc) it probably isn't worth the money. The HPP will change A/F ratios and ignition timing and in effect fool the computer to think the engine is as WOT when its really at lower speeds, but I always thought that is what your right foot is for

4. A thermostat change would be something you would do with the HPP above, but you may only see a slight driveability gain. Going too low, like a 160 degree F 'stat may cause some driveability problems at very low outside air temps (not to mention lower heater temps). A 180 F would be a better choice if you decide to change the stat. Also , if you have emmissions testing requirements, a 'stat like a 160 may cause problems. Some level of high engine temps are require to burn off moisture from condensation in the engine.

 

[Mangod00]

I decided to go with Borla's, Hooker Shorty headers and a K&N Air Filter for now...Should get it back next week....

 

[ohsobad]

I have a '94 with a six speed. Today I had the magnaflow mufflers installed, and they are simply terrific. Thats my .02 cents on exhaust.

 

[Moonunit 451]

I decided to go with Borla's, Hooker Shorty headers and a K&N Air Filter for now...Should get it back next week....

Lotsa magnaflo lovers, and I still need to hear some, but my Borla 2 3/4's sound BAD AZZ when I romp it and they set off lots of alarms at idle :cool Over 2,000 r's resonance is no prob

 

[Skant]

1) If you can do both, it's a good thing. But I'd do the cat back first.

2) The expensive cat back systems are worth it. And the cats do rob power, as far as I know. It's totally illegal to change them in the US on any car that isn't old. Or at least was last time I checked. In fact, it made a big problem in that if the cats were defective, legally your only recourse for a car that wasn't old enough was to scrap it (!). Crazy.

3) My experience with the Hypertech is yes, it does. So long as your car is mostly stock. Read Hypertech's site carefully. They tell you what they do and do not work well with. And my experience has been that their horsepower gain claims are accurate when hypertech is correctly applied. Note that in the corvette, they are not claiming large horse power gains. The stock corvette program is quite strong.

Hypertech is not magic. Their gains are obtained by leaning the mixture at wide open throttle. Their argument is that the stock program runs the mixture slightly rich in order to help the car tolerate poor quality gasoline. Hypertech says to immediately check the car for detonation during acceleration after you install their power tuning program, and that you may not run low quality gas in the car with their program or it will cause detonation. Even a car that aught to be improved by the Hypertech might suffer detonation instead, however this should be the uncommon case.

4) If you install the Hypertech, yes. If not, you'd be wasting your time. The stock program can make use of the lower engine temp. However, because the stock program doesn't turn the aux fan on until the temp reaches 230 degrees (!!!), the lower temp stat will have no effect.

- Skant

 

[86er]

Skant is on the money.

The cat-back is a great place to start, one of the weakest points in a Vette is its breathing.

Give or take a few HP, most systems are more sound preference than performance. What is the highest ADVERTISED HP gain anyway 28????? A good cat-back will enhance the stock breathing and make it sound a heck of a lot better. Flowmaster at $500 is a pretty sound investment over stock, but some people complain of resonance noise. Magnaflows have a lot fans in the Corvette world and in the US you could get a cat-back for about $350 delivered, probably not much more in Canada.

As far as the HyperTech goes... Again SKANT is right.......

They have a bad rap from people with more modified engines using them and getting minimal to less performace gains, but they DO improve SLIGHTLY on STOCK or slightly mod vehicles.

There are really 3 main benefits to Hypertech:

1. Turn fans on early - Works great with 160 (biggest benefit in my opinion)
2. Adjust power curve mainly at wide open throttle (a LITTLE more pep)
3. Helps little with Torque Converter

Don't expect too much, but you'll feel it. And believe me, even the slighest performance gains will make you grin!!!

BTW: The success of these mods will influence you to look for more, even if you don't want to. This is where it starts!!!!!!!!

 

[WhalePirot]

Welcome to the forum, Mango and enjoy your new ride!

Might I suggest a search of the forums, as you'll find many qustions you have and will have, posted with a lot of feedback. The search is a simple but easy skill to learn and reaps instant benefits.

On my warmed up, L-83, I found no difference in power between the stock CAT and a test pipe (illegal and long gone). The headers made a nice improvement as did the Flowmasters, which I liked enough to re-choose in the 3" system behind my new engine.