anesthes

I'm generalizing. I could just picture a bunch of guys with stock L98s bolting on this dual 3" x setup, hoping to pick up 15-20hp from their 245hp rig.. I'm sure on a 400-700hp application it could probably pick up 15-20hp with the right headers, assuming the x-pipe is in the correct spot. But whats 15-20hp, like 1mph in the quarter heh. $1200+ for 15-20hp is a lot of dough, assuming the combo sees a gain. Think about how much nitrous $1200 buys

-- Joe

88BlackZ-51

Do you think Caboboy needs true duals with the 421? I believe he has the flowmaster system with the 2.25 inch piping. That system doesnt flow too well.

If he gets a deal on a system, I think it would be well worth the install.

anesthes

I modeled it based on his specs in his signature. 421, afr heads, small lpe219 cam, and so on. Based on his rwhp, i'd say about 450 crank HP.
So modeled out we have a suggested inside diameter of 2.45". If I model it out to 500hp that diameter increases to 2.50". I think it's safe to say the OP might see 10hp. maybe 15.

His cam is too small.


-- Joe

mseven

I know you are, and that you are not making it a pissing match or stirring the pot. I agree, w/anyone buying that has no mods (stock)thinking this is a gain, it probably wouldn't be. As for bang for buck HP boost, yes NO2 blows it off w/out thinking.
My considerations were morover of having a good dual, and not too big of a tube. The idea of slowing the exhaust speed down to much at a point through using that much 3" tubing was a big consideration of mine. This business of 12-15 HP gain, is that RT's promo, or someones else's generalization? I never approached buying a system w/the idea of seeing HP just from going to dual system, let alone big tube stuff. Maybe, in combination of everything I did to this 350 there might be some small gains, for the most part I would attribute the gains to good heads, cam, intake and tuning etc. (this is for the sake of others who read this that are easily "swayed" by HP campaigns).
I originally just wanted a well made version of an LT-4 set-up built at 2 3/4". The Corsa had just come out ,or was coming out at the time and they wanted approx.1400+ for the LT version (@2 1/2") which would then needed modding etc. to fit up to the collectors.
(* just looked at my original bill I spent 888. to my door at the time)
I felt that the RT was an acceptable alternative, and being able to "fit" the L98 (sbcI) to begin with, good cats,etc. made it attractive. HOWEVER as we all know, almost nothing in aftermarket is that good/right.
For example, if I were to only have used the "rubber band" support from the c beam (as originally intended), I would have been collecting the parts of the street the first time I put my foot down on it ! I actually tried it that way when I first did some break-in on the set up, and broke 2 of those cheesy straps, that's when I bought hangers etc. Additionally you will not be able to use ANY trans support for the tubes (I tried working/modding an LT one (the stock one is out of the question) too tight w/3" stuff. If i would have installed it as they sent it, all the weight is then on the collectors and muffler hangers. which as we know is not good on slip fit pipes etc.etc.
I tried to express where all the concerns in this system are in my first post so no-one would get the idea that this system needs no work......it will. sorry for the long post

88BlackZ-51

He is making somewhere in the 370rwhp/500rwtq range. I think he is thinking he will gain 10-15rwhp approx. Tim might be planning on some more mods in the future, and I dont think that exhaust will be able to push the air needed after that.

-=Jeff=-

I honestly think going to the LTx style exhaust set-up over the OEM L98 is a step in the right direction..

on my 89 when I switched to LTx system I was running headers, but these are what I tried

Flowmaster 2.5" system
Stock LT4
Borla 2.75 Challenge system (from a ZR-1)
B&B with resonator then Xpipe
then dual 3" with a Custom Bassani Resonator with internal X and Dynomax Ultra Flow mufflers (Current)

I ran my best ETs and MPH with the Borla and my last system.

For my 90 I have a Borla challenge system and I might switch it at somepoint in the future

mseven

They have better band clamps available now that I would have used that go over both tubes of the slip fit joints. Hopefully this what you want to see:




After the "neck down" the tubes were shortened and re-welded (muffler choice plays a role), don't remember if originally was one piece, or had a weld there:

originally this straight peice off the last bend heading toward the muffler was a slip fit, I had it cut and and welded because of muffler choice and fitment:

88BlackZ-51

The back piping looks small. What size is that?

cv67

Not bad for a maggot. pretty hand towel.





























:

mseven

when I first was looking at putting together a system I had seen a pic of your set-up, and thought it was the best one I had seen for a L98 set-up.
2 1/2" ....looks small next to 3" stuff don't it.
I knew someone would "rag " on me ...

88BlackZ-51

Actually it does look smaller. I thought it was 2.25 inch piping.

A quick look at a 3 inch system. Your system does look good however. How does it sound?

'Shifter

This is essentialy teh same system I'm building, though at this time my motor is all stock. I'll be using
Hooker 2149's, hi-flow Dynomax cats, x-pipe back to B&B's, all 2-1/2"...can I expect much of a
gain? (Currently, I have teh pre-cat/cat single back to a Flowmaster cat back).

Also, to reduce resonance, what do you think of wrapping your pipes before teh cat-back?

mseven

Whose system is the one in the pic? looks good, and it looks like it will need some modding for the drivers side collecter extension.
It sounds good, and is fairly quiet overal until I hit the loud pedal. It has dyno max ST's in the back, but that may change. At the time there really wasn't many options, w/out a good amount of fabbing.

88BlackZ-51

That is my B&B system. You could get a set of B&B mufflers. They have the nicest looking tip out there in my opinion. I dont say that because I have them. I said that when I had my flowmaster's on as well.

anchami79

I really love this tip. Gotta be (one of) the best looking!

thirdtimevetteowner

mseven,
Your system looks awesome (like your motor, and everything else I've seen of your car), and 88BlackZ-51, I aggree w/you, they are the nicest looking tips. Think I'll go that way, when the time comes.

Rich K

-=Jeff=-

Cool..

now I wonder if you can buy JUST the X-pipe, I guess I need to give Chris a call..

Caboboy

Yo Marc! How the heck ya doin Bro!

Thanks very much for the pics mseven, that system looks terrific! I really like the apparent flexibility of moving the cats for fitment, not to mention being able to trim the other pieces here 'n there as well. I think it'd look pretty sharp with some Corsas back there too & maybe that way I could actually hear the stereo at cruise speed This may be the way to go depending on current price!

anesthes, I know your point and it's well taken.......analogous to the oversize header trap people fall into. I exaggerated a bit myself when I said 700, but my issue is this: I want a strong all purpose car, something that idles thru the shopping center like a stocker, gets 25+ mpg on the freeway, but can still kick azz when I hit my favorite onramp And.... I live in California and don't want to play the game when it comes to smog issues.

I really don't want to cam it, because then I'll need to be dead on with the tune when it smogs, and I'd need to look at gears My thinking is to cheat the duration gremlins when I do a 200 shot by getting more flow. That's the plan anyway. FWIW, you're very close to the projected HP gains......I did back to back dynos; one with a baseline and one with the headers open. I gained 20RWHP and I know it sounds crazy, but I also gained 5lbs torque. Weird huh?

Thanks for everyone's input, I really hate doing stuff like this twice 'cause it wasn't planned right the first time

mseven

Thanks Rich
you're welcome, I agree w/corsa's , man I tried for the longest time to get them to sell me just the muffs...no way

88Blackz51, those look real nice, and welded to boot, my only thing is I've heard that the b&b was real loud...are they?

johnnyevans

Joe, be nice!
The 90 system is pretty simple, 2149s 3" system with X, back to Flowmaster 2 chamber truck mufflers. It's fairly loud, but no resonance after X installed. Used 3" 90d pipe to make it.
89, 3" system back to dynomax ultra turbos, LOUD.
90 Convertible, modded stock headers with 2-1/2" to stock LT1 exhaust, by far the quietest. It'll probably stay until the turbo project burns the resonator out, then X it.
The LT system is hard to beat.
JOhnny