I'd like to hear experiences, opinions, and tips about runnung a true dual exhaust system on an L98.

To get the conversation started, I have noticed that all the systems pictured are without a crossover or balance tube of any kind. Is one necessary?

I've got lots more questions but I'm sure they will all be answered by your responses.

 

I had a local exhaust shop install the true duals on my old 90'. I noticed a slight decrease in torque but the power gains seemed sustantial. I didn't feel that it was too loud either. I thought this was a pretty neat exhaust setup.


[Modified by L98FIRE, 7:12 PM 8/26/2001]

 

Any other dedicated noise makers out there? :crazy:

 

Im planning on gutting my cats and cutting off the mufflers myself since I can weld. This way is cheaper than going with true duals and im on a budget right now, but I do plan on getting true duals eventually.

 

I picked up a used dual set-up, but haven't installed it yet. Take a good look at your stock front & rear y-pipes. They look pathetic (at least they do on an '85). I knew I wanted to improve my exhaust, but I wasn't sure which route I wanted to take. I was considering replacing the front & rear y-pipe and cat (my original is shot) or going with true duals. The prices I found were:
$200 Larger front Y
$100-$150 Walker or Borla rear Y
$120-$150 Cat
$420-$500 Total (less mufflers)
The above prices are for my 85, your 88 may be different.

$220 "True Dual" pipes

Even considering that I would probably reinstall the stock pieces (with new cat)when I eventually sell/trade it in, I'm looking at $350 give or take for duals.

I don't think any possible torque loss from duals would be too bad being that the pipes are only 2 1/4 inches. A balance tube might even help offset the loss. The rear section of the dual pipes are connected to each other in two places. You could easily get a shop to weld a short (2-3") balance tube in between before you install it on the car (to keep from being hassled about no cats).
I'll do a search, but one of the guys on this board did a couple of before & after dyno runs with pretty good gains from a dual set-up.

The thing that finally made my mind up was when I found a set of duals on E-bay for less than $40 :D . When I finally install them, I'll post some before & after G-Tech runs for comparison.

 

I found the link of when I asked the same question as you a while back:
http://forums.corvetteforum.com/zerothread?id=92975

 

bought my duals from MAD ($219) flowmasters from Jegs 2 @ $150...dual exhaust=$519.00 included freight....could tell the difference from the beginning :bb

 

I'm glad to see there are some power gains with this setup. That would be a pleasant bonus. My main reason for the change is to try to get the sound of my first Corvettes (mid year and early shark). The C4 just sounds alot different to me. I think it may be from the Y pipe combining the exhaust pulses into 1 smooth flow. You don't hear the 2 banks of cylinders firing separately the way you do with duals or sidepipes. I just like the older style sound better.

By the way, I plan on having no pre cats or main cat (there's no main cat now), and using the pair of KBD Targa mufflers that are already on the car as the only sound reducing device. Right now I have pre cats then a gutted main cat then the KBDs. Sounds pretty good but it's just not yet quite what I'm after.

 

es, i will tell you that you will notice a definite change in sound and performance with the duals & flows ..what puzzled me was when i swapped headers for the original headers/manifolds and did not notice anymore change in sound or performance from just the duals & flows? :eek: go figure

 

On my 89 396 Vette, I have TPIS long tubes. I'm going to install bullet cats on the ends and then pipe into a 92-96 Corsa stainless cat back. Should be awesome. The corsa has a cross pipe on the center muffler.

Jason

 

One thing I forgot to ask.
Will the complete lack of cats cause O2 sensor problems or codes?

 

Not that I know of . They come with a O2 fitting.

 

ES,
I installed the Corsa LT1 exhaust system on my '91 L98. The install was a breeze, and the results were well worth the effort.

All you need is a set of LT1 ('92-96) exhaust hangars (about $28) to install the system.

It is a true-dual exhaust with a cross-over pipe at the resonator. I even put CATS on mine to keep it legal...it's nice to be able to rub that one in :lol:

If you don't go with CATS, the install is really easy, you'll just need a muffler shop to bend a new head-pipe from the exhaust manifold (or header collector) to the input of the resonator. They'll need to weld 2 tabs with holes to the middle of the pipes to bolt the front hangars to. I had mine done in stainless to go with the rest of my system...cost was $125.

 

try to put in 2 crossovers to cut back on noise i used a true dual exaust then i put in 2 crossovers and it took a lot of the ringing out i now have headers going into a single 3 inch pipe then into a borla y then in to 2 and 1/2 inch flowmaster i like this the best for not being too loud and it was about 2 tenths better than the dual setup what ever you decide try and go with mandrel bent pipe

 

Thanks for all the great info everyone.

Here's the latest news. I got an estimate from the exhaust shop that was rated as the best in town by the local 'Vette shop. The quote was $240-250 to build the system from the manifolds back to the mufflers. This did not include the mufflers. This seems high after reading what some of you paid but it is right on when compared to the "kits" from Eckler's, MAD, etc. What do you all think?

 

SO WHAT HAPPENED :seeya

 

I just had duals installed a few hours ago. I did use a balance pipe as it sounded like a really good idea and wasn't too much more $$$ at all. The exhaust guy said that it's not necesarilly(sp?) needed but he'd do it.... so I had him do it. He said it's not needed because most emitions vehicles have a device that balances the exhaust automatically. I have never heard of such a device before, myself... <shrug> so if my balance pipe is just for redundancy then oh well...

:cheers:

 

not redundentcy but lower decibles i know :D

 

Corkvette1, how did you get high 11's out of that 85 :eek:

 

that is mid to high 11s and here is the link to all the modifications http://hometown.aol.com/aheis46312/myhomepage/auto.html
:cool: