Exhaust removal questions (worth saving?)

[RussMcB]

I'm removing my original '91 exhaust to replace it all with aftermarket parts. The top two bolts behind the cats are tough to access and I haven't been able to break them loose yet.

1) Any suggestions for the best tools to use to get to them? I have a fairly good selection, but no success yet. I may run out to buy some wobble extensions to see if they might help.

- or -

2) Any reason why I can't just cut the pipes and be done with it? Is there a chance this 25 year old exhaust might have some value to someone some day? I hope to never use it again ever and I'd rather not store it for years only to eventually throw it away.

Thanks.

[We Gone]

When doing exhaust heat is your friend. A hand held propane torch will work. Be careful...

[Racinfan83]

Lot's of PB Blaster penetrating oil, and I used a socket with a u-joint to get em off my '90. Actually used the same bolts to put the new one on. It takes a bit of time and effort but my original came off all in one piece. I have it standing on end in the basement against the wall...

[RussMcB]

Thanks for the suggestions. I sprayed it with breakaway fluid a few days ago, but the bigger problem is access.<snip> I have it standing on end in the basement against the wall...Yeh, that's kinda what I wouldn't like.

Do you think you'll ever do anything with it? In my case, it would probably would hang around for a few years until I finally decide to throw it away. If that's the case, I might as well cut it off behind the cats with a cut-off wheel. I can't really imagine it ever being used again.

[jimmy b.]

Save it, if its in good shape somebody could use it. Keep it high and dry. I just found a really nice original exhaust for my 94. Some day I'll put it on but for now I like my Corsa just fine.

by the way what do you plan on replacing it with

[Dynomite]

When doing exhaust heat is your friend. A hand held propane torch will work. Be careful...

Yes.....exactly :thumbsup:

I use an acetylene torch on the exhaust manifold bolts as well as the Injector Housing Coolant Manifold bolts. On the Coolant Manifolds you have to heat the length of the bolt (on the housing) which extends through a hole in the Coolant Manifold (four bolts).

I use SS Bolts when re-installing the Exhaust System.

See Item #3 and Item #6 C4 Beam Plates and Installation (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-2.html#post1581480716)

[RussMcB]

Save it, if its in good shape somebody could use it. Keep it high and dry. I just found a really nice original exhaust for my 94. Some day I'll put it on but for now I like my Corsa just fine.

by the way what do you plan on replacing it withI got a good deal on new OBX headers and slightly used aftermarket cats and a Borla cat-back system. I also took advantage of the ZR1.net Registry discounted price for a new SW crossover tube.

I went to a chassis dyno last week to get my "before" exhaust upgrade power numbers and they were lower than expected. I spoke with Marc afterwards and he said most likely issue is clogged original cats. I'm crossing my fingers that's true, and this exhaust upgrade should be +70 HP(!) :-)

[Fully Vetted]

I've still got my original exhaust down at the shop wrapped in bubble wrap. Along with the original gear shift, gear set, wheels, tires....It all came with the car.

[KILLSHOTS]

I got a good deal on new OBX headers and slightly used aftermarket cats and a Borla cat-back system. I also took advantage of the ZR1.net Registry discounted price for a new SW crossover tube.

I went to a chassis dyno last week to get my "before" exhaust upgrade power numbers and they were lower than expected. I spoke with Marc afterwards and he said most likely issue is clogged original cats. I'm crossing my fingers that's true, and this exhaust upgrade should be +70 HP(!) :-)
Headers and a cat-back (with cats) and you were expecting 70+ HP? Try half that, at the very maximum. I doubt my headers (without cats) and Corsa added any more than 25 or 30 HP, even after Marc reworked my tune to add fuel for the headers.

As far as what your stock system is worth, just list it for sale and you'll find it's worth nothing, unfortunately. I made sure to keep most of my pristine 15K mile system when I replaced it, and it all went straight in the trash when I sold the car.

[RussMcB]

Headers and a cat-back (with cats) and you were expecting 70+ HP? Try half that, at the very maximum.I shouldv've included a smiley when I typed that. :-) It was tongue in cheek - a reference to someone else's recently post about a 70HP claimed improvement from an exhaust upgrade.

However, *if* my current exhaust is truly clogged and is costing me, say, 25-30 HP, then it is possible I will gain more than the normal upgrade increase because I'll be fixing the problem to get it back to normal, PLUS getting the normal improvements from headers and exhaust.

I'm not worried about any magical numbers. I just want it to be as strong as it should be, and sound better (it's pretty quiet now).

[We Gone]

Russ, if you don't mind what kind of #s did you get stock? If I remember when I did mine Stock it did 324rwhp.

[RussMcB]

Around 296-299 RWHP (five runs, two different dynos).

I have Marc's chip, wired open secondaries, new coils & injectors, (everything else stock, 67,000 miles). I went to the dyno to get pre-header baseline numbers. I was expecting something closer to 330 or so.

Yesterday I sent my chip to Marc for recalibration (more fuel for the headers). We'll go back to the dyno after that and hopefully I'll be around 345-350. If not then we've ruled out the clogged exhaust as my main issue and I'll need to look at other possible causes.

At first I was disappointed with the low numbers (and that's why I went to another dyno a week later, for confirmation). Then I realized there is a bigger jump to be gained, so it should feel pretty great after fixes and current underway upgrades.

[Z51JEFF]

If you decide to junk the exhaust I'd be interested in one of the mufflers,well actually just the exhaust tips.

[RussMcB]

If you decide to junk the exhaust I'd be interested in one of the mufflers,well actually just the exhaust tips.OK. Send me a PM with your email address and I'll send pictures.

[We Gone]

That's not bad numbers Russ, After I did Marc's chip and just cat-back flowmasters I did 339rwhp-346tq... the next step was to the 510 package. I ended at around 490 at the FW but I still run cats and duel mass FW.

[RussMcB]

That's not bad numbers Russ, After I did Marc's chip and just cat-back flowmasters I did 339rwhp-346tq... the next step was to the 510 package. I ended at around 490 at the FW but I still run cats and duel mass FW. Which numbers are you saying aren't that bad? I think 296-299 is noticeably down on power. But if your talking about my expected number (~330), then I agree. I'll be happy with that.

I know this is wishful thinking, but I REALLY hope I'm satisfied/content with the car after headers. There's no doubt the 510 package is fantastic, but that would mean my cheap "$10K Corvette" investment (the initial price I paid for the car) would grow to $25-30K. I doubt I could hide that expense from my wife. She's already commenting on my checking account balance's rapid decline.

Therefore, please don't ever give me a ride in your car. :-)