Twilightoptics

Finally finished my exhaust. Made a huge seat of the pants difference over the 2 7/8" and even a significant improvement over the 3" cutout I had.

I think I'm okay posting more than 3 images since they aren't thirdgen hosted right?

Dual 3" mandrel bends. H pipe. Two 3" Hooker Aerochamber mufflers. 3.5" Stainless steel slant cut tips.










Lowest part is shown with Dr. Pepper can. Which doesn't hang down any lower than my cat had.

meridius

that looks good, I was gonna do that to mine untill my stupid state came up with the laws that we have to have emissions equipment for the new visual inspection.

Cadillac

Oh... old hat here in CA.



Beautiful work with the pipes.

Envious just south of you,

klumb15

iTrader: (1)

that is awesome!!! i would love to do that, but it ain't happening, that is some pricy fab work i know that..you did an awesome job...what is that gray stuff that you coated it all with? awesome car too, i'm puttin dual 3" on mine with dual 40 series i think, its either dual 40's or dual aerochambers like yours...but i'm putting long tubes then straight back hugging the driveshaft tunnel, then dumping right before the rear axle....you got a sound clip at all? i'm not sure if i wanna go with 40's or aerochambers...i understand the 40's are louder, but the aero's sound awesome i guess....but i figure dual 3" exhaust is gonna be loud no matter what...do you have any experience with each of the mufflers, which one should i get? your car is awesome by the way, i love everything about it!..

Twilightoptics

Thanks for the feedback guys!

Klumb: I can tell you this.. I drove around for about 20miles without the tips on, so the exhaust hadn't exited PAST the car yet... the resonance was FIERCE inside. To the point that my ears wanted to implode. With the tips on it's much much better.

The H pipe is supposed to make it quieter also. It's LOUD now. Just a warning for the dumping before the axle! Be prepared!

The coating was just VHT 1500º Paint. I just didn't want it all to rust. The summit exhaust pipe I used, wasn't a very thick gauge and would rust farely quickly. Since I park the car outside (sucks I know) and it's primarily a weekend warrior... I opted for some paint. Two cans, $15, no rust





EDIT: Had an epiphany! Laptop I use for tuning the commander + microphone = sound clip

The first one is from about 3ft back from the exhaust. The 2nd one is about 10ft back. They are about 1.4mb (I don't know how to scale them)

Idling in park/gear/park/rev

Exhaustnear
Exhaustfar

Blown383

Looks great! Looks like you spent a lot of time on it. How much did it all cost? How's your suspension clearance? How did you clear your panhard bar?

jaredi

Yes please please pictures of going over the panhard bar. I'm going to do that kind of setup on my IROC as soon as I get a chance only with an X pipe and probably 2.5" pipes. I've seen pictures of people that have had to "adjust" their PHBs to keep from crushing the pipes.

Was just wondering if you had any clearance issues.

Jared

Twilightoptics

I wedged the pipes in with the panhard brace. The pipes don't come anywhere near the panhard. LOTS of room with stock height. I don't seem to hear any metal rattles. I did have to flex teh heat sheild a little bit.

8 Mandrel Bends =$160
2-4ft straight pipe= $25
2-Aerochambers=$120
2-Hangers=$10
H-Pipe Kit=$50



Jaredi.... if you do an X pipe you need equal length headers, or to engineer poper length of pipe so that when they meet the X pipe, they are equal to the block. If not, you can have the sound waves smash dead on into themselves in the center of the X pipe and get NO gain what so ever. Which is why I opted for the H pipe. Did lots of research on the subject.

305q_ta86

iTrader: (1)

Very, VERY nice!


I want your car lol.

klumb15

iTrader: (1)

yea its real loud if you don't have turndowns, but a budyd of mine has a built 350 with duals dumped before the rearaxle, and 90* turndowns, take some much of the interior resonance away its amazing how much turnodowns will make, so i'm gonna do that, plus 3 layers of sound deadener on the interior, i figure i'll be alright...

mw66nova

iTrader: (13)

i have 2 1/2" true duals with dumps infront of the rearend and no sound deadening material. it is very drivable. i drive it everyday like that. it's only uncomfortable at like 1000-1100 rpm. then it vibrates everything in the car! every other time it is very nice.

onebinky

iTrader: (1)

Good job on the fabrication, sounds pretty good too :-)

What kind of setup are you running where you need dual 3" Must be really moving some air...

Great job

Twilightoptics

See Sig above

jaredi

Well looks like plan B - LTs and a modded X-member...

Thanks for the info, I'd never really considered it.

BTW, Beautiful car...

Jared

CraZ-28

That's a pretty cool lookin setup.

Tobias05

Hey Twilight I've been debating 3in dual exhaust myself for a little bit.

I have a 350HO w/ a RPM intake, 1405, and hedman hedders.

Would 3in be overkill for my application? I'm running 2 1/4 right now w/ thrush glasspacks, and in dire need of some adjustments.

Thanks,
Brandon

Twilightoptics

What heads and cam? If it's mild, yes it's overkill.

I've got Pro Topline heads, an Holley Stealth Ram, and a 239/247@.050 Solid Lifter cam. And I am the borderline.

unknown_host

iTrader: (1)

Twilight- in that first pic, did you have to clearance the frame at all?

Thanks

Twilightoptics

Not the frame itself... but there was a piece of sheet metal that was strone from the frame up to the underbody. It looked like it really served no purpose. I took a cutout wheel and cut slits in it, so I could pound it flush with the floor pan and the frame, then welded the seems.

Didn't do anything to the frame itself.

ssxmac

iTrader: (1)

so when are you going to make me one

seriousally, really good job though

-chillen

327_TPI_77_Maro

iTrader: (8)

Wow, thats the best job I've seen doing duals on these cars. Most guys think that since they fabricated a dual exhaust that turns out in front of the tires, they have now done the unthinkable, they have beaten all odds. If an exhaust doesn't come out at the bumper, it's not a full system and isn't really worthy of daily driver use (plus in most states a half length exhaust is illegal). How fast is your car that you needed dual 3" though? That seems rediculously overkill. Dual 2.25" full mandrel bent pipe will get you down deep into the 12's in the 1/4 mile, with mufflers. Dual 2.5" mandrel bent should be enough for anything that can be driven on the street. You'd have stock ground clearance with dual 2.25s in your configuration.

Twilightoptics

Nothing hangs lower than the factory stuff with cat did.

I'm fast enough to need it according to alot of people, and slow enough to not warrent it according to alot of people.

I'll tell you this, single 3" flows more than dual 2.25".... a large improvement was noticed with DUAL 3" vs a SINGLE 3" NO Muffler.

Dual mandrel 2.5" is good for around 400bhp.

ET has less to do with power.

327_TPI_77_Maro

iTrader: (8)

You can directly calculate how much work it takes to run the 1/4 mile in a given time. Hence, ET has everything to do with power. Plus, in a practical sense, I know a guy with a big block chrysler with dual 2.25" pinch bent, not madrel bent, exhaust, with mufflers, running 12.5s, in a heavy car. People make too big of a deal with huge exhaust systems when they aren't "needed". I went from dual pinch bent 2" exhaust to dual 2.25" mandrel bent exhaust and gain .00000 in the 1/4 mile (back when the camaro was running 14.30s carbureted and launching bad)

unknown_host

iTrader: (1)

There are a lot of cars that need dual 3" exhaust and even bigger on the street. Big displacement, big rpms and forced induction all benefit from bigger exhaust.

unknown_host

iTrader: (1)

Judging from your profile, you also have a small displacement small block, stock heads and TPI. I am not surprised you didn't gain anything.

And MPH = horsepower, ET = using that horsepower.

Twilightoptics

Word. That's exactly right. ET is putting the power you have, to the ground. Which is why I've seen people with more HP than I have around the same weight car, run slower.




That guy with dual 2.25 BBC.... I bet he'd improve with 2.5" on the dyno. I spin my engine to 6500 RPM. Also with as long a system as we have, bigger can be better because of the boundary layer. Go do a little research there 327

black355formula

thank you thank you very much.you are running shortys correct cus thats what i have and i dont want to mess with putting new longtubes on mine.

Twilightoptics

Yep Hedman 1 5/8" Shorties! Weld a THICK 3bolt flange to the bottom of the header before you make the exhaust. Make sure you place it where you can get to all the bolts! Those slide flanges get weak and warp and such.

fbody83

Twilight, how much power is that 355 making?

rjmcgee

Ask him in 2 months after we dyno. That is some nice work though and I can't wait to see it in person. I think I am in trouble when we get to the track.

Twilightoptics

Rodney, I've got access to a dyno this 26
th of February and John might be going with me. We'll find out then!

BadBowtie88

Twilightopics: You are a MACHINE! That is the finest job I have ever seen. And the fact that you did that with shortys is even more amazing. I like your motor combo too. I can't wait to see dyno #'s and track times. Absolutely fine work man.

12secformula

I'll second that, FANTASTIC!!

onebinky

iTrader: (1)

Make sure you post up, I'm curious to see what you pull too

rjmcgee

You suck. Are you going to dyno it again in April?

Twilightoptics

Of course, you know my combo gets upgraded every few months!

Demon355

iTrader: (1)

Dude...awesome setup! Got any sound files?!?

19doug90

how did you manage to fit 2 3" pipes over the rear end

Twilightoptics

Dewey316

Of course we are. This is a pre-dyno, dyno. This is to make sure that Mike, Myself, and Paul all smoke you on the dyno.

Besides, by April, I'm sure all three of us, will have changed something. (well, I may have just boughts parts, and put them on shelf. )

Demon355

iTrader: (1)

Didn't even see it...lol sorry! Awesome sound dude...killer!

rjmcgee

You shouldn't say "smoke" and "dyno" in the same sentance.

You hoping to finally get over that 200 rwhp hurdle this year?

Dewey316

I'm hoping to just not break something, and potentialy run on 8cyls. Shoot, making to and from the dyno without issues would be an improvement.

83 Crossfire TA

iTrader: (2)

As an alternative, you can run a bead along the engine side of the flange, the bead will both pull that side back (welds/heat cause metal to shrink) and result in a thicker ridge on that side of the flange that will prevent it from happening in the future. That’s what I did with my headman shorties.

Any better pics of where you ran the driver’s side pipe under the engine? I know on my car with where the outlet was and the spacing it was difficult to put a 2.5” pipe in there and ended up with that section getting crushed about once a year (I got really good at cutting the bottom section off and just replacing the outside side of that bend), and mine looked like it tucked up better then yours.

89camario

hey man i wanna do the same to my '89 iroc, for some reason i can't see those pics is there any way to send them to my email at monstrano@yahoo.com so i can get an idea of how to do it.

thanks again!

Xophertony

yeah, i see no pics and hear no sounds.

pigsticker

Same here, no pics, no sound.

Twilightoptics

Guys, this was from a year ago! The images were not hosted through TGO. Nor were the sounds. Tony, you've heard my car!

Cardomain has some pictures.

Xophertony

yeah... but if i had a sound clip i could listen to it in the comfort of my own home. i could also listen to it from the comfort of my own home if you drove by