Exhaust for max performance.

[HAWAIIZR-1]

Originally Posted by Corbusa

Ok set me straight on what you think. I do like the OBX system ( a lot) and I was ready to order , But its only 2 1/2 in.. So I'd be better off with 3in.? whats the power loss dropping down a size in the pipe? I can not find 2 3/4 stainless pipe .. My thoughts are now to order the dynomax 17228 or 17519 . I found 3 in stainless pipe pretty cheap and I have a friend who is a pro who can install it.. just so I got it straight , 3in is better and the X pipe ( magnaflo) will replace the resonator? and it is 3 in..?
Will it be an issue to go from the factory exhaust 2 3/4 to the 3 in X pipe and make a connection? ( i'll do the OBX headers later ) , & I noticed the polished mufflers are cheaper , that seems backwards .. also what length exhaust tips are usually used? I see the muffler says 2 1/2 exits and the tip says 2 1/2 will that slip fit correctly? Well I guess that enough dumb questions for this evening.. Your wisdom are greatly appreciated..Thanks

Okay, flame suit on here is my opinions for what it is worth. I personally cannot get the concept of smaller pipes than stock 2.75...period. Although proven my Marc H and others to provide more power, please see why on Marc's presentation here: http://www.zr1specialist.com/HAT%20W...%20Systems.pdf

Having said that, I know the weakest link in my B&B system is the mufflers itself and I don't know that a 350 motor actually can benefit from 3" pipe, but I like it and have it already so I'm going to work with what I have. Beside it looks cool as heck from the rear and everyone says, "Wow, them are some big pipes!" Everyone has an opinion of what is loud and too much resonance, or their own reasons for why they like what they do and what sounds good to them. I have no idea what an LT5 sounds like with the dynomax ultra-flos but I like what I read and how some other cars sound on you tube. If you are a conservative person, you probably won't be happy and too loud and too much resonance.

As for the X pipe, I would not put a 3" unless that is the size of the exhaust you are using. I only chose the SW x-pipe because it is 3" and B&B would not work with me. As a matter of fact, I received my x-pipe from SW today and very pleased and not chambered, just plain x-pipe (will post a photo later). From what I found there was a little bit of clearance issues with MF and other X pipes with our narrow tunnel area and I also don't like the design and transition with too many degrees in the X.

About the tips that I wanted (double wall from dynomax) they are a bit long at 12" and 9" before the taper (3" to slip over pipe). A 2 1/2" tip is designed to slip over a 2 1/2" pipe. I'm trying to confirm the measurements since the dynomax is 1" shorter in length than my B&B mufflers and I think too much will stick out the back. Right now the B&B tips are flush with the bumper and I might need to find different tips that are a few inches shorter than dynomax 36473. I think dual 4" tips would looks awesome and double wall, rolled edge is nice with slant cut. Some have said that the doublewall might even help on drone, but not sure where it actually comes from. It might also help to have tips extent a little beyond the bumper too, but not sure.

If I was anywhere else in the US I would have ordered my dynomax ultra-flo mufflers and tips to get some custom work done. Here in Japan the labor is crazy expensive so I might live with my B&B, Version 3 (restricted mufflers) for a little bit and see how I like the X pipe first. Anyway, that is my 2 cents for what it is worth......not much, but it is my story and I'm sticking with it. The proof of principle will be when I get to tune and dyno my build so see if all the theories are confirmed.

If not in a rush, I would go to the Gathering and listen to all the Zs there to see what you like. Then max power is a whole different story and advice from folks like Marc H and Hib H and invaluable since they have dyno proof and years of knowledge and experience. Best of luck.

[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

[rhipsher]

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

I like that idea. Nice and simple. I went over some railroad tracks one night 5 years a little to fast and it ripped a big hole in my Borla resonator so until I could find another one I had the muffler shop just weld me some straight pipes from the cats all the way back to the mufflers. It was a quick fix but I hated the way it sounded. Sounded like a giant lawn mower. Once I got the res from Brad I had it installed and it sounded so much better. I don't really know if the straight pipes actually added hp but it did dyno at 339rwhp with them so I never dynoed it with the resonator. The next time I dynoed the car was after the top end porting so I'll never know if the straight pipes helped. All I know is it sounded funky.

[HAWAIIZR-1]

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

Pete,

If the stock pipes are good and no replacement needed, this is the best budget conscience upgrade I have ever heard of. Do you think the LT5 needs at least 2.75" and up pipes? It would seem GM/Lotus/Mercury Marine would have done some testing during development with the exhaust systems? I'm sure some guru out here already knows the answer. I wonder why even companies like Corsa when developing the 2.50" went smaller instead of at least staying with 2.75"? Did they think it was too big? I know they had sound, db level, resonance, comfort, emissons and many other things to consider during development.

[Gunny]

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

[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.

[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

[HAWAIIZR-1]

Originally Posted by Corbusa

Ok set me straight on what you think. I do like the OBX system ( a lot) and I was ready to order , But its only 2 1/2 in.. So I'd be better off with 3in.? whats the power loss dropping down a size in the pipe? I can not find 2 3/4 stainless pipe .. My thoughts are now to order the dynomax 17228 or 17519 . I found 3 in stainless pipe pretty cheap and I have a friend who is a pro who can install it.. just so I got it straight , 3in is better and the X pipe ( magnaflo) will replace the resonator? and it is 3 in..?
Will it be an issue to go from the factory exhaust 2 3/4 to the 3 in X pipe and make a connection? ( i'll do the OBX headers later ) , & I noticed the polished mufflers are cheaper , that seems backwards .. also what length exhaust tips are usually used? I see the muffler says 2 1/2 exits and the tip says 2 1/2 will that slip fit correctly? Well I guess that enough dumb questions for this evening.. Your wisdom are greatly appreciated..Thanks

Just wanted to let you know that we might not want the Dynomax 17519. Even though polished I read somewhere that it does not flow anything like the 17228 and also not welded so that is why cheaper I think. I sent an email to Dynomax to ask a bunch of questions, but no response as they get a lot I'm sure so I will call later when I have the time in the right time zone. I'm passing on 17519 and probably get 17228 since welded and their catalog does not give any specs about the 17519 other than size. I wanted a little bling because I'm replacing the polished B&B, but rather have the power and sound over the bling.

[XfireZ51]

Guys,

Al is currently installing the Dynomaxs on my car as we speak.
He sent me a couple of pics from the install and I should have the car this weekend. I'll post the pics shortly and you can get an idea of what they're like.
The Z06 tips really add some bling. They're like Corsas on steroids as far as the tips are concerned. I looked at Pete's last night and he is using the B+B tips and we discussed how to connect the Z06 flappers to vacuum so they flip open at WOT. I also took a video of the MFlows at idle and I'll do the same with the Dynos for a compare. BTW, Al has a set of new Dynos available for $160.

[HAWAIIZR-1]

Cliff,
Thanks for the idle speed and no good video yet. Stock exhaust on now too. What are your thought about how the SW mufflers are designed and flow? Paul G from SW said they are turbo mufflers but they don't know the SCFM flow. I like the wide tips they have for ZR-1 but only fits their mufflers with the dual tips.

Dom,
Thanks and can't wait to see and hear this set up. I bet it is friggin awesome. I thought about Al's deal, but the shipping for me is the deal breaker........too bad.

George,
I know you meant the Dynomax Ultra-flo, just wanted to mention because it seems Dynomax has some turbo mufflers too, but the flow is very restricted like 1/3 the Ultra-flo design and not a straight through design.