I know I run the risk of getting this thread pulled from the moderator and all (since it's prolly been asked a JA-ZILLION times!) but I just spent an hour looking and searching for the answer to these questions and keep drawing BLANKS BABBYYS!!! YYYARGGHH!!

Here's the deal:
I gotta '89 RS with a LT1 goin in. I want TRUE-DUALS all the way back, and as LEGAL as possible, but MOST IMPORTANT - I want MEGA-SOUND thunderin out the rear end! WHOOO!! I'm lookin at Hooker headers, catco cats, and GMMG chambers.

Here's the questions:
1. Long-tube or shorty?
2. DO I need to get headers that have all the pipes and tubes like the stock manifolds?
3. Will TWO catco cats fit in the stock location or do I need to look at another brand?
4. How large I.D. can I go with when routing duals in the same channel as the original single?
4. How much significance does the I.D. of the piping have on overall sound output?
5. IS there a less-expensive version of WIllie's setup? His setup is premo, but my wallet ain't.
6. What is the best alternative to chambered mufflers for best sound-output.
7. This is hitting an all-time low, but do the tailpipes have any infuence over the sound of the exhaust? I like the flat 4th-gen Z-28 tips.
8. Last but not least, my car's lowered (2" I think) - is that gonna be a problem or not?

As you can tell, I'm more concerned over the sound of the car than the performance. I'm not planning on hittin the 1/8 or 1/4 any time soon, I just want it to sound as awesome as humanly possible. PLEASE help me out here MANN! Thanks a MILLION in advance - fellow F-body BROTHERS!! BTW, Once I get everything ready to roll, I'm gonna have my exhaust maestro gimme all the measurements of ALL the fabricated piping, and all the parts necessary and I'll post it on the forum PRONTO!!

 

that is going to be the deal breaker there there isn't any room to run the exhaust pipes down the drivers side as it is ie no floor pan space like on pass side. Considering that its lowered I'd say the true duals are out also the long tubes since they aren't far from the ground once you lower your ride.
I'd say get some hooker headers 1 5/8 primes 3 inch collector run all 3 inch pipe back on the pass side like stock toss in a 3 in and out catco highflo cat and a spintech muffler and dump it at the rear wheelsunder the car. I have stock manifolds (with hooker super comps sitting in my living room) stock cat and 3 inch in and out on it 3 inch all the way to an 80 series flow 3 in and out then exit pipes facing the rear of the car with no tips as mine is lowered also and I would drag the things off the back of the car pulling into half the business entrances here in ft worth.

I even have problems scraping the 3 inch pipes on the pass side with mine and thats with them channeled under the car floorboard. You dont have a channel on the drivers side so its very hard to run tru duals on the 3rd gens. now if you want to spend the dough just to turn around and spend it again because the exhaust is laying down the street then go ahead and run true duals but I recommend not doing it. You may get by if you put stock springs back on, but you will loose gas miledge ( due to the car being more resistent to wind turbulence) loose handling (also due to the car being higher and the stock springs aren't as stiff) and also looks.

 

THANX for the info MICHAEL! I've read it's a lotta work, but I don't see getting A TRUE-DUAL symphony outta a FOOL-DUAL (single) system. I gotta do the duals even if I do gotta be more careful with the driveways and stuff. One question I didn't mention and just got finished reading about is this: What's the deal with H-pipes and X-pipes? Are they necessary and what's their purpose? I gotta buddy with a Mustang GT that's gotta factory H-pipe, but then again it's got true duals, also from the factory with Flowmaster 40's - and it's pure EAR-CANDY! Thanks a MILLION again brother!!

 

I'm sure others can go more indepth on this but they are designed to equalize the pressure and iir in both pipes. How they work I couldn't tell you. You would think with the pressure in the pipe it would just go by the opening for an H pipe as it is a 90 * turn now I can see how the x pipe would work. An x pipe is more beneficial then an h pipe though I have heard.

 

Yes.. no way to run pipe on the drivers side at all and it will never work on a vehicle with drop springs...

 

First off, this won't be legal. At all.

1. Go long or go home.
2. Only if you want to retain AIR/EGR. I suggest deleting them.
3. Yes, just give your exhaust guy some creative license.
4. 2.5" would work.
5. A larger diameter pipe will typically give a deeper tone. When talking true duals just go 2.5 for your power output.
6. Gotta pay to play.
7. Big can of worms there. Personally I'd just dump them out of a couple magnaflow 1 chambers.
8. Yes they do, but it's a minimal one.
9. Yes, LTs hang low and so will your duals.

The purpose of the crossover pipe is to equalize the exhaust pressure. On our cars at any given time on a bank of cylinders (odd or even) two of the cylinders are firing at damn near the same instant. Both of those pulses are going to compete for space in the collector. At the same time those two pulses are fired, the opposite side of the engine is silent, so there's a gap in air pressure. A crossover pipe will allow some of the pressure to bleed off into the other pipe, decreasing backpressure and shortening the tuned length of the exhaust.

An H pipe is just that, an H. It's a 90 degree bend of pipe connecting the two duals, shaped like an H. It's usually slightly larger than the other two pipes. Most people say Hs sound better. The X pipe is, of course, shaped like an X with the two pipes crossing in the middle. It tends to make more power as it's less restrictive. Unfortunatly with an X pipe at a certain RPM it tends to make a harmonic reasonance, usually caught by the human ear as a loud humming noise.

 

You guys are the BOMBS babyyy!! Here's the deal, there used to be a link somewhere off this sight from one of the threads - I had it bookmarked, but now its a dead link. THere were several guys that had their cars lowered with duals. One guy in particular had a white IROC with duals going down the right side like I'm talkin about, plus he had a sound clip and it sounded FRAWESOME (FREAKIN awesome). I realize there will be a ground-clearance concern, but not much more than I already have since I got the car lowered (speed bumps, RR crossings, etc.) but my biggest deal is the fit over the rear axle - will the two 2.5"'s fit? URBAN, thanx for all that info on the X's and H's. Remember that to me SOUND is better than POWER, so it looks like H-pipe's the way to go. As for the LONGS vs. SHORTS, what's the benefit of LONG? If all LT is better for is output, I'd rather go with shorties for the ground clearance. Along those lines, you said 2.5's'd be better for output, but how much difference is that really gonna make in sound? I just gotta get all these questions answered before I start making orders and talkin to the exhaust maestro! Thanks again - fellow F-body FRRREAKS!!

 

honestly I would not go with LT look in this forum a little for pictures of LT on f bodys. They end up being very low to the ground most pictures I've see are lower then your oil pan. As for two 2.5's over the rear axle they will work but why not order a spintech muffler that will fit on the pass side under the car before the rear ie after the cats. and just dump the exhaust there at the rear seats. That will make it louder since you will be aiming the pipes at the ground and also save you money on extra pipe to the rear and the custom charge for fabricating the pipes over the axle? If you are running the pipes only on the pass side I don't think you can even fit a h pipe or x pipe. not to mention if you are running dual cats and then into a 2 in 1 out spintech and dumping them there will be no need for the h-x pipe as the location you will be putting the h-x pipe will be where the muffler is then the exhaust will dump after the muffler. Just an idea.

 

That would be willie and yes, it's possible.

https://www.thirdgen.org/forums/exha...ml#post1006733

 

YEA that Willie really got the DEAL! I'm waiting for a response from him right now, since he seems to have the EXACT setup I'm lookin for. Michael, I'm talkin' about DUAL ALL THE WAY, not 2-into-1 at ANY POINT. Dumping at the axle sounds pretty sweet n' easy, but I want tailpipes, just looks sweeter IMO. It looks loke chambered's are the way to go, shorties for the ground clearance, and dual 2.5" so far. I'd like to find a set of headers (ceramic, or SS) that don't cost a fortune, but it looks like I'm gonna be shellin out over $600 BUCKS for that setup, even in SHORTIES! YYARGHHH!! Thanks again a MILLION for all your replies. Like I said before, if I end up with a setup that really RIPS, I'll get all the measurements and parts listed on this site and remmeber - you heard it here first babyyy!

 

you could adapt one of these to fit if you dont wanna fab it up yourself

LT1 PRODUCTS AND PACKAGES

 

Yes, dual 2.5" will fit in the stock routing.

I agree, H pipes sound better and don't reasonate. The power difference is minimal in your application anyway.

You will have better ground clearance with shortys. HOWEVER - it may be more expensive to make a Y-pipe for them, you'll lose about 15-20 rwhp compared to LTs, and LTs sound WAY BETTER! I say LTs all the way, but if you're set on shortys - they're better than stock.

The reason I said 2.5" is I don't know if dual 3" pipes can fit in that location and you don't need dual 3" as far as power is concerned (unless you're doing heads/cam making 400+ rwhp). If you can fit two 3" pipes, go for it if that's your thing. It can only improve things, won't hurt anything..

I'd recommend paying the exhaust guy to strategically flange your exhaust setup with 3 bolt triangle flanges (he'll know what you mean), that way it's easy to remove.

 

LT1 PRODUCTS AND PACKAGES >> Looks like a sweet setup, FORMULA350, but it looks like its for the 4th gen only - YYARGHHH!! Thanks for that info again URBAN - if the pipes are gonna be the same distance from the ground as the LT's, I'll go with the LT's - Like you and TONS of other F-body-bros have said that they're better than shorties. THANKS again for all your imput BROTHERS!

 

From what I have been led to believe Lt-1 and 3rd gen exhausts are almost identicle with exception of tailpipe and hanger locations the 2 chassis are similar enough from the firewall back that adapting that to fit shouldent be all that big of a deal

 

yep! I've owned thirds and fourths and they're pretty much the same, nothing that a good exhaust shop can't change.

 

Well based on my experience with my ebach pro kit and my 3 " exhaust I would seriously not recommend running anything over 2.5 down one side. I can take pictures of mine tomorrow. I hit mine on quite a few peaked inclines because of the wheelbase and also on some speedbumps. This is with even going over them at an angle not a direct attack which is worse. And the only place I was talking about turning the pipe into a single is where it exits the muffle which if you wanted to dump it would be maybe 5-7 inches long. It would be your turn down pipe out of the muffler. But as stated by another member there is room to have the h or x pipe on the side.

 

you need to look long and hard at this pic

that is lt on an unlowered camaro move those pipes 2 inch's lower to the ground and take a look at where you drive. Those pipes may be behind you on the road ;-P If you know where the spohn relocation bracket is located and know how far that hangs down which is less then any pipes you run in that area (which isn't keeping the stock routing where are these people getting that all over this board) I hit the spohn mount at least once a day if I do alot of driving sometimes on country roads if there is a small dip in the road that I don't know is there yea I will know its there afterwords man that will hurt your lower back when you nail that bastard on the asphault at say 35-40 mph.

Running the exhaust anywhere near the trans IS NOT stock routing the stock pipe is on the pass side under the seats it doesn't even get close to the trans. Another thing you need to think about if you do any long trips or anything with your car is the transmission is the hottest part of your car. If your running hot pipes right by the trans your not helping the heat issue. just some more 2 cents out there.

 

That's LOW-BRO - I see what URBAN's talkin about with the LT's suckin up ground clearance! It looks like 2.5ers all the way back. I still ain't decided what to do from the axle back, but its lookin more and more like Willie's got the benchmark set on that chambered system, even if it does cost more than I spent on my entire freakin' LT1! WHOOO!!!