Exhaust for max performance.

[1990 quasar blue]

Great thread guys. Lots of good info. I wonder how much my 2.5" flowmaster is choking it up. I get constant compliments on the sound but if it's costing me more than 10 hp..... it's gotta go.

[Gunny]

Thanks for the offer ... but I need to clean the garage (ultimatum from wife).

Currently on my 90 ... Borla Challenger (2.75 pipes). It will be for sale when I take it off in the next few weeks.
Other systems in the garage

• The original stock exhaust ... it needs a home, too.
• LT4 stock system
• two magnaflow SS mufflers (the ones that have ZR-1 hangers, twin tips, and bolt directly to the original 2.75 system
• complete Corsa system ... probably will be my final exhaust when I finish playing musical chairs with exhaust systems.

Used to have but sold to a neighbor ... another Borla catback (2.50 pipes).

At one time I had 5 exhaust systems for the Z and when my wife asks why I need so many exhaust systems hanging in the garage then I know it's time to thin the collection, but before I do I am curious about adding an x-pipe and the magnaflow muffs to the LT4 pipes to see what the results will be.

George

[bdw18_123]

Originally Posted by Pete

To keep cost down use the stock exhaust cut resonator off install X-pipe,cut mufflers,install Dynomax mufflers, done.

My first mod was i cut resonator off stock exhaust,installed 3" H-pipe with Flowmaster mufflers 3" inlet/dual 2 1/2" outlets, Z was running low 12's at 116 MPH,after that was headers and ported plenum/IH best was 11.59 @ 120 on GSC's had to slip clutch i used to go thru clutches like they were going out of style this was almost 10 years ago and it was unheard of.

I still have that old exhaust.

Pete

Sound like a good idea to save money. What about the resonance with this sort of setup though? By removing the resonator, won't resonance be a problem?

I was actually thinking of getting that OBX system, but maybe I'll do it this way (if the resonance isn't too bad) since it sounds like from what you guys are saying, it would be better and cheaper performance-wise to just mod the stock system. I'd like to put exhaust on my Z and I do want it to be a style that maximizes performance and sounds good, but if there is too much resonance it will be way too annoying on long trips, not to mention the headache factor.

I have the stock exhaust on right now, but the mufflers aren't the really big ones. They are stock GM ones, but are lots smaller (probably half the size) than the stock ones on the '91-'95 ZR-1's. Maybe only '90's had them? So maybe the smaller mufflers are somewhat louder than the bigger versions, I don't know.

[sammy]

cost i spent modding the stk system originally. 90 for the summit 3 in narrow x pipe 130 total for the dyno max super turbo 3 in with dual 21/2 exits hacked off the tips from a 91 zr1 exhaust . 150 to have it all welded together . if one wants it totally quiet without losing but maybe 5 hp would be to go to the 21/2 in cherry bomb turbos with 21/4 in exits .. i am going to go to the cherry bomb 21/2 in as i am an old guy thats done with drag racing and want it quiet . lol

[HAWAIIZR-1]

Originally Posted by tuband

Pete, Craig, et al,

Pete's mod of removing the restrictive parts from the factory pipes and adding flow mufflers & H pipe got me to thinking. I have spare parts in the garage that I've been wanting to mod & fab up similar to Pete's description. Here's what I have ... a complete LT4 cat back (reportedly one of the most free flowing exhausts for the C4) and a pair of Magnaflow SS mufflers (3" in - twin SS tips). I'm looking at a 3" x-pipe sold by Summit part #643130 that indicates the following dimensions: 3" aluminized pipe, 5" center to center spacing, and 22.75" total length.

But the photo tells a slightly different story unless I'm looking at this thing completely wrong

According to my calcs a 3" x-pipe on 5" centers should have a 2" clearance between the 2 pipes. The LT-4 pipe centers (at each end of the resonator) is very close to 3.5" leaving approx. 3/4" space between the pipes. This is why a narrow x-pipe is needed if trying to align original pipes as well as fitment in the tunnel. Looking at the photo it certainly appears to me that the summit x-pipe doesn't have much more than 1/2" clearance between pipes which should make for an almost ideal fitment to the stock pipes.

Has anyone measured this particular x-pipe? Is the photo correct or is the description correct? I live about 3 hours away from Summit-Atlanta but I don't have time to make that trip in the near future. Last time I was at Summit and wanted to check a "catalog" item, I was told that I had to buy it at the counter, then the item would be pulled from the warehouse & given to me within 10-15 minutes. If I didn't want it then I had to go to customer service and do the return merchandise bit ... when all I wanted them to do was to look at the item and check a measurement. That process seems bassackwards for the customer. Nevertheless, if the Summit narrow x-pipe is a close fit it should be fairly easy to fab up my spare parts into an interesting exhaust for very little out of pocket cash.

Thoughts? Advice? I'm curious about the possibilities and I've really been interested in the good info coming from this discussion. Thanks in advance.

George

Hi George,

Sorry, I don't have the measurements and left the X pipe in my office. From what I gather you might not be interested in B&B or SW pipe as they are pricey.

I spent the money to get the SW even though it is the price of more than 3 of these that you show. The good news is there is no baffle in the SW x pipe any more. This pipe is designed for direct replacement of B&B resonator and even Stainless Works advertises it as such; I have no idea how it works on other systems. Here are the photos for what it is worth to those that are considering SW works pipe:












I can post measurements for comparison tomorrow.

[Gunny]

Originally Posted by HAWAIIZR-1

I can post measurements for comparison tomorrow.

Thanks ... that would be helpful.

[Gunny]

Originally Posted by bdw18_123

What about the resonance with this sort of setup though? By removing the resonator, won't resonance be a problem?

That's one of the reasons that I want to experiment with the narrow x-pipe, LT4 pipes, & Magnaflow SS muffs. I'm expecting some resonance but if not too bad, then I might try this setup for awhile. You gotta love experimentation (except for the cost).

George

[Gunny]

Originally Posted by sammy

90 for the summit 3 in narrow x pipe lol

The summit 3" narrow x pipe you used ... same as pictured in my earlier post?
Do you know the center to center measurement? How about the space between the 2 pipes?
Summit's picture looks like it's less than 1" space between the 2 pipes which would allow easier fitment to a stock system.

George

[Corbusa]

This thread is great info !! So far I am probably going to get the dynomax mufflers, ( not sure which tips ( due to the length needed )
I did find some 3" x 5' stainless exhaust pipe fairly cheap( $35.00 + $ 10.00 for shipping ) ( I might be able to talk to the company and get a zr group deal if enough want to order ) I'll use from this for the x pipe to the mufflers.
So I'll wait on the x pipe and see what you guys come up with..
also I had an 88 vette , and the exhaust pipe twisted somehow , It ended up touching the rear bumper and started to burn the paint . So now I'm courious does some one make a stainless metal shield that could clip to the bumper where the exhaust exits, to act as a shield?? That would also add some bling..
I'll probably also double clamp the exhaust in that area to make sure it cant ever move ( yea now I'm gun shy -I'd go nuyz if the bumper got burns on the Z..

[Pete]

Corbusa,here you go $200 complete Stainless.
http://zr1specialist.com/HAT%20Web/F...For%20Sale.htm

Pete