Anyone with Stainless Works exhaust system with the turbo chambered mufflers?

[HAWAIIZR-1]

Originally Posted by mike100

I had single outlet turbo mufflers on my last 95 LT1 car and it wasn't excessively loud. Previous to that the last owner had some 2.5" L98 Borla twin outlet mufflers put on and it was crazy- the single outlet thing is a must. I realize single outlet mufflers aren't very vette-like, but this was ok for 'ol purple-erkel during the year I owned it.


That's why I suggested getting parts together for a custom NPP job on a more universal hi-perf muffler on the stock pipes. The NPP mufflers or flaps from a C6 are what will cost you. The rpm switch, junkyard solenoid, tubing, vacuum switch etc will be about $110. The project takes time- but it is fun to be able to have a selectable muffler. The other reason is I believe the stock pipe diameter and chosen pipe thickness is part of the acoustic engineering that went into it. I x-piped the resonator on my 1990 pipes and it barely got louder- I know if I cork up the right muffler and then have a flap on the second outlet, it ought to be able to stay similarly quiet. btw, my car is a 91, but I got Han's old 1990 stockers and Dominic's old Magnaflow x-pipe.

As far as the smog thing- yeah- I ran my headers while I could, but I drew the Star station inspection so I wasn't so sure I'd have a prayer at passing the extra thorough visual. The car is back to stock manifolds. I have to admit it is very tame to daily drive (but you don't really get used to losing the extra pop that headers, porting, and cat back gave you). Long term I'm looking into buying a cabin in an unenhanced zip code to get out of the bi-annual inspections, short term I'm thinking about doing NPP muffs as described above on my stock pipes since I have all the parts for the control side still hanging on my car.

Hey, I really do appreciate all the info you are sharing and so much to consider. I'm glad I have folks to run this stuff by so I don't reinvent the wheel, especially with someone living in Cali that understands the pain to go through. I don't have much knowledge about SMOG too since only one truck (My 03 Lightning) and I don't count the wife's VW Golf since 2014 and just required by CA bringing the car in state.

I was thinking about the mufflers and what you mention about single tip. I already have a new set of Dynomax with single in/out 3" I was going to do some experimenting with my 90 B&B some years ago. I would have to probably get new 2.75 to match pipe if so or reduce the inlet and see how that works. I did find a 2.75 x pipe but have not confirmed the center to center and length to see how much work is involved or just go the Magnaflow (I almost bought one from Gunny a few years ago). I have to do more research about the resonator on the 95 to see how restrictive and worth the gain or resonance to eliminate with x pipe. The cool thing about the single outlet idea is I found a tip that looks just like stock on 95 with the wide single opening, but only 2 1/2" inlet. Then there are others that branch off into two tips from a single. Not sure if that is the route to go or like you said and build a custom NPP mufflers to stock pipes.

I'm on the fence to hack up the 95 exhaust and was looking to initially just remove and keep (but for what?). I always keep stock stuff that I will probably never use and all of it is just getting in my way. I have all the bolt on stuff from my 90Z, Lightning, and Harley and need to just get rid of the stuff. No more room. I have this thinking that the next owner will/may want all the stock stuff. WTF?

Thanks again for your thoughts and info. I wish you were a lot closer. Are you thinking about attending the ZR-1 Gathering in Vegas during Oct if that pans out?

[HAWAIIZR-1]

Originally Posted by mike100

One last thought on air injection tubes on headers: The Watson ones do not work- look at marc H's website articles on the matter... you have to keep the diameter right and the tube has to be far away from the header flange. The pressure is too great where the watsons go in and it will burn out your one-way check valves. I had to replace two or three of them when I put back my stock stuff. I will be taking those off next time around.

Thanks for the info. I was going to send my current set or buy a set of OBX to have modded by Marc if so. I think Marc's would be modded like factory setup. Just trying to figure out the cats if so and did see that you found the Z06 or ZR1 cats to work and similar to size of ours. I even had a thought to have the stock manifolds extrude honed or ported, but it does not seem worth the effort if there is any gain compared to the cost. I do have an extra set of 93-95 manifolds to play with.

[HAWAIIZR-1]

I have to finish detailing this 95 later today for next week's car show so I'll get under the car and check out this exhaust system to see what other thoughts I have. I do remember seeing how it chokes up the pipe going into the mufflers and I remember so other choke point mentioned with the resonators?

[mike100]

From what I have heard that only the 1996 LT4 cars had a good resonator that didn't crimp down to a small diameter.

Interestingly there was also one year on Z51 L98 cars that had functional 2-outlet mufflers.

[HAWAIIZR-1]

Originally Posted by mike100

From what I have heard that only the 1996 LT4 cars had a good resonator that didn't crimp down to a small diameter.

Interestingly there was also one year on Z51 L98 cars that had functional 2-outlet mufflers.

I read similar about those LT4 resonators and I wonder why only one year and only that engine chosen for use? If available, I imagine the cost is not worth the HP if any.

That is also interesting about the Z51 L98 too.

I can't seem to find a 2.75 X pipe and the one found earlier is 2.75 to 3.00 inch.

[Gunny]

I have SW headers, no cats, and the LT-4 exhaust on my 90. As far as I can tell the LT-4 resonator has very little restriction (perhaps the least of any C4 stock exhaust) plus it has an H balance tube behind the resonator. I'm very pleased with my setup. I could (should) live with the existing setup but I'm very curious about adding cutouts (ala WarpTen) and will probably do so in the near future. I've also thought about adding hi flo cats but may leave it as-is for now.

FWIW, I've had Borla 2.5 (stock manifold), Borla 2.75 (challenger system, headers, hi flo cats), Corsas (headers, no cats), stock 95 (headers, no cats), and finally my current setup. Spent too many $$$ from point A to point B but it was an interesting (even eye-opening ride). Main thing I learned is that exhaust is a highly personal, very subjective decision and what works for some will not work for others.

I think the improvements/developments made using the flapper system has been a great step in the right direction and opens up a lot of possibilities that we may yet not have seen.

I'll be curious to see/hear what you work out Craig. Give me a call sometime.

[mike100]

Originally Posted by HAWAIIZR-1

I read similar about those LT4 resonators and I wonder why only one year and only that engine chosen for use?...

I would imagine because they couldn't justify making another change to the LT5 system emissions-wise and paying for more retesting (for the 448 cars a year). The LT4 was a re-cert for OBD-2 so they probably were looking for a few more hp on the LT4 without adding more cam or ign timing so I bet the resonator was an easy area for improvement.

[HAWAIIZR-1]

Originally Posted by Gunny

I have SW headers, no cats, and the LT-4 exhaust on my 90. As far as I can tell the LT-4 resonator has very little restriction (perhaps the least of any C4 stock exhaust) plus it has an H balance tube behind the resonator. I'm very pleased with my setup. I could (should) live with the existing setup but I'm very curious about adding cutouts (ala WarpTen) and will probably do so in the near future. I've also thought about adding hi flo cats but may leave it as-is for now.

FWIW, I've had Borla 2.5 (stock manifold), Borla 2.75 (challenger system, headers, hi flo cats), Corsas (headers, no cats), stock 95 (headers, no cats), and finally my current setup. Spent too many $$$ from point A to point B but it was an interesting (even eye-opening ride). Main thing I learned is that exhaust is a highly personal, very subjective decision and what works for some will not work for others.

I think the improvements/developments made using the flapper system has been a great step in the right direction and opens up a lot of possibilities that we may yet not have seen.

I'll be curious to see/hear what you work out Craig. Give me a call sometime.

Hey George,

Thanks for your thoughts and info. Wow, you have had quite a few combinations of exhaust systems too. I am more confused than I ever was. I really wanted to just buy a bolt on system and call it a day. I really thought the SW system with chambered mufflers would fit the bill and maybe it still will.

I don't know if worth trying to do the LT4 resonator (maybe just replace with X pipe?), but I measured the outside (yes, outside) diameter of the pipe going into the 95 muffler and could not believe only 2.25". What the heck were they thinking? So the inside diameter is only a little over 2" depending on the gauge of steel used. Then the single outlet is only 2.25 in outside diameter too so it is really choked by the muffler too. I think it was Marc H that mentioned it on his study. I see why even the Corsa at 2.5 makes a difference by design.

I agree with you about subjective and very personal to find what each individual likes/wants, but it can get expensive quick by experimenting. Another thing is trying to find the right shop to do custom work can become very frustrating. I will give you a call so we can chew the fat about exhaust and other things. Thanks again and take care!!

[HAWAIIZR-1]

Originally Posted by mike100

I would imagine because they couldn't justify making another change to the LT5 system emissions-wise and paying for more retesting (for the 448 cars a year). The LT4 was a re-cert for OBD-2 so they probably were looking for a few more hp on the LT4 without adding more cam or ign timing so I bet the resonator was an easy area for improvement.

That makes sense. I did look at how the pipes get small going in and out of our resonator. I already had the car down so did not take measurements, but maybe same like the pipe going in and out of the mufflers at 2.25. So this 95 system is choked at the resonator and mufflers and still higher flow that the earlier years. No wonder it sounds like crap and muffled when recorded.

[Gunny]

Originally Posted by HAWAIIZR-1

.... (maybe just replace with X pipe?).....

I've also been interested in this mod to the LT4 system (or late LT5 system for that matter) ... I believe the X-Pipe "might" be an improvement. Talked with Tony D. at BG and he's experimenting with an H pipe and that sounds promising also. I would really like to hear/ride in a Z with the same setup I have except with the X-Pipe or H-Pipe replacing the resonator.

I think the next thing I want to try is cut-outs and perhaps that will be the last step. Each time I change something I swear it will be the last change but then the "bug" bites and I can't wait to try something else. One concern (fear?) is that I will arrive at an acceptable system (sound, performance, etc.) then take it one step too far. I've already done that a couple of times and it's frustrating ... but I suppose the "experimentation" journey can be fun at times ...