exhaust
 

have been looking at 3 inch exhaust from the headers on back. I have a flowmaster force II system and no cats. I have no drone but would not mind louder sounds. I found a place that would make me a stainless steel mandrel bend 3 inch system with mufflers (dont know which ones flowmaster two chamber??) for about 1200 or 1300 dollars. This would be with xpipe all custom made.

he then showed me a t-100 aluminum exhaust. It is 1/4 or the weight. It is amazingly light. If anybody wanted his zr1 to lose weight this is at least 100 pounds lighter. He could make me a t-100 aluminum complete exhaust for a little over 2k. It is the lightest exhaust I have ever seen. The complete exhaust, pipes, hangers, mufflers, xpipe is all aluminum and welded and 3 inch. This is a killer exhaust and very high end. am thinking about it. Anybody have a 3 inch exhaust with no cats?? how loud is it?? idle? full open throttle??

ed ramos #3028:)

Re: exhaust
 

I have headers with no cats and the Corsa system, which is 2.5" diameter but basically straight pipes. It is extremely loud at WOT, so I can imagine the system you're considering would be extremely loud as well.

But hey, the louder the better! Sounds like it would be a nice system if you found the right mufflers.

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Schrade just put on a 3 inch with x pipe, headers and I think no cats. He did say in a post earlier that he had some cabin drone with it. Schrade are you there?

Re: exhaust
 

what would you do if you had a flowmaster II exhaust system? would you cut away the resonator and put an x pipe? I have no drone but I dont care if I do. I drive it so little that my brief driving sessions must be intense. Or should I leave the resonators and change out the mufflers? I have heard those corsa's with headers and no cats and they sound great. I want more sound. Maybe no resonator and 2 chamber flowmasters??

Re: exhaust
 

some people have said that the problem with the flowmaster is the mufflers. too restrictive. Is that true? the resonator appears to be restrictive since both pipes coming off the long tube headers go into one resonator. what does a resonator do??

Re: exhaust
 

If it were on our 94,it would stay there. I had Jeal headers,no cats,and Flowmasters on my 90 ZR-1 and it sounded great! But,since I have a pair of B&B Fusion mufflers,guess I will put those on the car,,someday.
Find you a set of the first gen B&B exhaust,if you want surround sound in full Technicolor.

Re: exhaust
 

A resonator tunes out drone at a certain frequency...it is a little higher up in the rev range, not the drone you get in the hatch lugging the car in 6th gear up hills with a loud muffler set.

My experience is that headers with stock mufflers and no catalysts decibel volume-wise is about the same as a free flowing 3" pipe set with cats.

Did you see any of my posts with the C6 NPP muffler valves I installed? GM, Porsche, and BMW use this device on several cars. It works very well. This way you can run a restrictive, quiet muffler and the second outlet runs a straight shot allowing you to have your cake and eat it too.

Re: exhaust
 

Dynomax VT mufflers do that.

Re: exhaust
 

Marc has said before that the problem with Flowmaster is the resonator. I think the mufflers actually flow quite well by themselves. If you like the tone, you might be fine just hacking those off and using them with your new 3" system.

Re: exhaust
 

What the VTs don't do is allow you to turn them on or off. A significant part of the drone is attributable to an AFR that's too fat or rich. And it really gets going when you're in the 55kPa+ region of the fueling(VE) table. The exhaust gets "blubbery". Leaning it out tightens the note. Ever notice how the drone goes away on trailing throttle and a slight decline? But climb the incline with a slight acceleration and it gets obnoxious particularly around 1300-1600rpm.

Re: exhaust
 

HUH? YOU SAY SOMETHIN'?

http://www.emofaces.com/png/200/emot...hearingaid.png

You better think twice edramos.

Sounds great from outside. But resonance inside is beyond impressive.

In-cabin drone at low RPM's is HEAVY. It's got to be near the 16Hz range @ low RPM's.

Once I get the water out of the tank, I'll get dB readings for as-is, with cork sheeting in new roof headliner, with more cork sheeting under cargo carpet, and lastly, some type of resonator for 2 x 3" inlet + outlet.

Re: exhaust
 

I want to make a change but i don't want a mistake. The flowmaster system is good. there is no drone inside car at any speed. It is probably restrictive and if you want a meaner sound then a different system is required or a modification of the current system is in order. It is a crap shoot as to what to change on the current system. some say the resonator is the problem/ some say its the mufflers?? It would be horrible to cut up the system only to find out the modifications are less than desirable.

The flowmasters sound very good at wot but just not aggressive enough at idle or low speeds. I have seen that flowmaster makes the 44 series and the 40 and the 10. the ten is for race cars and its a one chamber muffler. it sounds ratty and too crude so its not a nice sound. the 40 and 44 series are two chamber desire and sound nice. Maybe that is the ticket??

Re: exhaust
 

Who here hasn't had at least 3 exhaust systems:p. For me it has been about 1 per year.

Re: exhaust
 

yeah on my other cars I have bought many exhaust systems. they can get quite pricey. I dont want to make that mistake plus I have no where to keep take off systems. I will wait a while and see what surfaces. I like the sound of the corsa's only with headers and no cats. Hopefully somebody wants to change to another system and sells their corsa.

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I'm on my 3rd since February! ;)

Re: exhaust
 

Yeah Ed, I jacked around trying to find a less expensive option. I ended up with stock catted manifolds into straight pipes and it sounded AMAZING! Then I remembered I wanted headers and that would have been FAR too loud with those straight pipes. Like you, I didn't care much about drone at the time. I love the deep sound of B&B but wanted a custom system with an x-pipe and black tips, and the price they quoted me was ridiculous, even though I'm local. In the final analysis, I decided that since I was spending $1400 on a frigging catback (I have the black-tip Corsa...more expensive) I wanted to have it ALL, including no drone. I'm glad I stopped experimenting and spent the money on the only (IMHO) true best-of-both-worlds exhaust system. Hope this helps somewhat. Good luck!

Re: exhaust
 

yes it does help. If I want the sound of a headers/no cat Corsa, I need to buy one.


ed ramos #3028

Re: exhaust
 

I don't at all regret this hardware - my motor is running MUCH cooler with it - there's NO doubt about it. If I could readily put OEM hardware back on and spec it for difference, I would.

But I do want to decrease interior drone here, without getting any restriction back - won't be east to do right...

Re: exhaust
 

I started out w 1 7/8" Watsons w 3G B+B. DRONE.
Went to headers w MagnaFlow 3" Cat-Back including resonator. Nice exhaust but more restrictive although it still made 399rwhp.
Now my final configuration is headers, SW Xpipe, DynoMax UltraFlows w
NPP Z06 tips and full open on/off switching. This is the exhaust I'm sticking with.

Re: exhaust
 

Hey Schrade, Daryll (GoldCylon) had (probably still has) a Corsa resonator for sale. It's 2.5" but a totally straight-through design. Might be a way to reduce your drone without adding restriction.

Re: exhaust
 

Speaking of restriction which causes backpressure. "The 1993MY upgrades included going to an exhaust that reduced backpressure by 2" of hg(mercury) was responsible for 6 bhp of the total power increase" of 20 sae net hp.

When the Engineer responsible for the MY1993 power upgrades (Mr. Graham Behan made the above statements, he uses bhp(brake horsepower). I have no idea if a brake horsepower is the same as a SAE net hp or not. If a BHP=SAE net hp, then the reduction in backpressure by 2" of hg, was responsible for 30% of the 20 sae net hp upgrades for MY1993.

I think that many people swap out exhausts (myself included), because it one of the few ways to completley change the personality of a car. While power increases are often stated as a main reason, in reality the search for the desired audible characteristics are the heart of the matter.

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Where's Daryll here...

How long is your Corsa resonator there D? What are the inlet and outlet centers in inches? THink it would fit behind my X-section here?

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I'll save you some money. I just took off my 3" Magnaflow system and went with catless Corsa (has got to be the loudest on the planet). Selling the whole system for $400 plus shipping.

http://www.zr1.net/forum/picture.php...pictureid=2641

http://www.zr1.net/forum/picture.php...pictureid=2642


It does drone but I dynoed at 430 to the wheels with this system so it flows very nicely.

Re: exhaust
 

Quite possibly, the only sound better than an LT-5 with headers into a catless Corsa system at 7000RPM is the sound of someone saying, "Hey, you want this suitcase full of diamonds?"

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LOL...NO DOUBT! It is an absolute hellacious sound. It sounds more like 10,000 rpms. Absolutely intoxicating...

Re: exhaust
 

With the Corsa system is it the resonator that reduces the drone? I ask because it is straight through. I thought what really helped the Corsa be drone free was the fact that they only flow through one pipe in the mufflers.

Also I have SSW headers, random tech cats, and a flowmaster force II. I agree it's fairly quiet at cruise and idle but, it absolutely screams over 3500 rpm's. I couldn't imagine going louder. People tell me they can hear it coming 1/2 mile away if I'm getting on it.

Re: exhaust
 

I agree with both of you. the catless with headers corsa is the most raucous. That magnaflow is at a good price but I dont like the sound of magnaflow too much. I spoke today with a flowmaster engineer and asked him how I could improve the sound of my force II system. He said not to remove the resonator since this is what takes most of the drone out of the exhaust note. He said in tests conducted by flowmaster that the resonator hardly makes any back pressure and flows nicely. He said that he would change the 60 series mufflers that came with all zr1 force II kits for a series 40 two chamber muffler. He said drone would be only slightly increased but the car would certainly be much louder and especially under wot. I might try that since its only a few hundered bucks with custom tips. flowmasters have no fiberglass stuffing or anything inside that can over time wear out. I have had a few flowmaster systems in various cars and they always wore very well and looked great. the two chamber old school non delta force muffler is loud and sounds like a race car in wot. this may be the trick for less money.

ed ramos #3028

Re: exhaust
 

Yes. The resonator is key to keeping the drone out. I would not remove it if you don't want drone. I would take out the cats and let that corsa sing!

Re: exhaust
 

The stock exhaust was designed to muffle sound, of course. But it was also tuned to eliminate the inherent resonance baked into our cars. It hits hard in the 1800ish RPM range and again in the 3400ish RPM range. The resonator was tuned to help part of it and the mufflers were tuned to help the other part of it. The exact details don't matter, but to answer your question somewhat succinctly, the Corsa system was designed in much the same way, except with much less restriction. What you have in the Corsa is a system that is somehow as effective at quelling resonance at all RPM as the stock system, but still causes virtually NO restriction. It is quiet at part-throttle but straight-pipe loud at full-throttle. Any exhaust can sound throaty or be "open" but in my opinion, the Corsa is brilliant because it just does everything right.

Re: exhaust
 

true but.... the corsa 1300.00 compared with the two 40 series mufflers at 160.00. quite a difference.. might be worth a shot?

Re: exhaust
 

Chris is right. Over 20-odd years of owning ZR-1s, I tested and used a half a dozen systems and the Corsa was the best aftermarket system for flow (HP), sound and lack of resonance. Designed like the stock system to eliminate the resonance at the two rpm points that our cars really have it. Had Corsas for probably 12-15 years total. However as most of you know by now, I finally went back to the stock 95 system with electric cutouts for racing and just making noise when I want to. Usually run with them about1/3 open, but close them when I come back into our subdivision to appease my wife. Really like the set up. Quiet when I want it (say a long trip) and as noisy as I want other times. Headers, no cats, when open basically a straight through system as the stock resonator has little flow resistance. --Bob

Re: exhaust
 

Thanks Chris. The reason I was wondering was because the guys running the NPP tips on a 3" system with X-pipe all have little to no resonance as long as that one tip on the mufflers stay closed.

Ed, it would seem that the 40 series would be the cheapest way to get more sound. I bellieve they're still aluminum so weight should be similar. Sorry I took this a little off topic.

Re: exhaust
 

Certainly true, Ed. I felt the same way, so I started making changes to my stock system. I got a great sound but it was pissing-off-the-neighbors loud, and since my only "mufflers" were the cats, the whole system had to go when I installed headers. Those "experiments" didn't cost me a whole lot, but when I finally decided to spend the dough and install the right system, what I had spent on the experiments ended up wasted money. If I had it to do over again, I'd have gone straight to headers and Corsa and saved some time and money.

Re: exhaust
 

I went with the cat back Billy Boat 3" X-pipe exhaust system on my ZR - result was impressive. Although I cannot tell you how much improvement in terms of HP, I can tell you the car feels better under full throttle and although there is substantial drone at certain RPM's, the end result makes me smile! The look from the rear is also impressive.Cost was right at $1,000.

Re: exhaust
 

If you look closely at the Corsa Resonator (specifically) you'll see a circular slot opening in the pipe section near the front of each of the resonator pipes. Like blowing air over the top of a pop bottle, a resonance is generated, dependent on the internal dimensions of the resonator - not unlike a pipe organ.

As it happens, the wave pulses created within the resonator cancel those exhaust pulses of the same frequency - and it occurs at that slot in the through pipe you see in the resonator.

And, IIRC, the mufflers too have (Helmholtz) resonators in them; shorter than the those in the resonator; designed to address the resonance occurring around 34K RPM.

Google "Helmholtz Resonator" for an in depth reading and how it is used for noise cancellation.

Re: exhaust
 

It looks like when I do decide to do a change, I will go with a muffler swap from my 60 series flowmaster to an original 40 series old style flowmaster exhaust. I know I will hear a significant difference in agressive tone and rumble. I will keep the rest of my flowmaster system including the resonators to limit drone somewhat. I drove my car today with flowmaster force II system and it is somewhat loud and under wot aggressive but I just want more. I dont drive her much so when I do, I want the looks, the power and the sound, plenty of sound. I should cost my around 400 dollars to swap mufflers and add tips. I cant believe that tips have become so expensive. they average 60 to 100+ bucks. I think this should work. My car is great and sounds good now but with this new setup it will be very impressive sounding. rumpty-thump!!

ed ramos #3028

Re: exhaust
 

Just FYI Ed, when you do this, you will be keeping the most restrictive portion of the Flowmaster system, which is the resonator. Also, since you plan on changing the mufflers, you may experience more drone, as your exhaust was designed as a complete "system" and therefore, Flowmaster probably took the drone characteristics of the LT5 (and the C4, in general) into account. You'll be altering that.

Best of luck with the mods. I hope you find the sound you're looking for!

Re: exhaust
 

the flowmaster tech said that the resonator is not that restrictive. He said that in testing that there was not that much difference with or without the resonator. He said that the resonator is in place to change the pitch of the sounds and play them off each other so the noise in the cabin would not be too loud. The resonators are just under the floor in the cabin of the car. The mufflers have baffles inside unlike corsa that is straight through with material around the pipe inside the muffler, maybe it is the muffler where there might be some restriction. The muffler used in the zr1 flowmaster kit is a 60 series muffler. It has 3 chambers so the exhaust gets tossed around quite a bit inside that muffler as noise is bumping off several baffles canceling each other out until it finally exits the muffler. the corsa goes straight through and depends on the material that is wrapped around the perforated pipe inside the muffler to eliminate the noise. Over time, the corsa's material inside the muffler will break down and the exhaust will become louder.

the 40 series is a 2 chamber design so it will be louder and it will have more drone and less back pressure etc.. but it is ok. I believe it will work and its worth the shot. If for whatever reason I don't like it then I will opt for the corsa.

ed ramos #3028

Re: exhaust
 

I just did the first test of drone reduction with the extra-foam / painted top, over glasstop.

I did a recording with each. It was a little quieter with the painted top, and when I played it in a media player with graphic EQ, it IS slightly lower volume.

Next test with cork underlayment under interior cargo carpet area. I don't think it will reduce drone enough more, to take the edge off...

And I can't get over the sound like an exhaust leak. HAS TO be the crossover section. There is no exhaust leaking - of that I'm sure...

Re: exhaust
 

I would try some styrofoam or foam over the top of the spare tire so that it deadens any resonance of the hatch floor. Could it be that the spare tire carrier creates a BOOOM Box under the hatch floor?