1G: My DIY 3" turbo back AWD Pics inside

GSLENK · 04-20-2012, 02:07 PM

Price breakdown for the curious:
stainless:
3" ebay DP $50

Alumized steel:
two - 3"x5ft and 1 - 2.25" j bend $70
two 3-hole, 2.25" flange $10
one 2-hole 3" flange $10
one 3-hole 3" flange $5

Need to buy:
DMH cutout $180 new or cheaper used if I can find one used...

Not bad, "full exhaust" (oem muffler/dump) for <$330.

I was toying with the idea of dunping the exhaust at the downpipe... Well I tried to mock up the dump, And I was never satisfied with fit, or potential heat/exhaust damage...

So I made a turboback (w/ ebay DP, $50 for DP is cheaper than even the raw steel to make it)

I used a shitty $90 HF flux wire feed welder w/o sheilding gas. Needless to say the welds suck and are very labor intensive. Im still chasing down leaks, but Im almost done.

The Main idea is to have a straight 3" tube all the way back, and dump right under/behind the rear axle (once I get a dmh valve, I will weld the flange on... till then I sealed it off, b/c I'd rather not mock it up w/o the valve). then the last <2ft are factory-ish 2.25 and I reflanged the muffler to a 3-bolt universal If I decide to go aftermarket later. I prefer stock quietness for now.

I eventually plan on lowering the car, but As it sits... I seem to not have clearance issues. The lowest part is 3.5" (bottom of 3" straight pipe).

I didnt make this a tech article because Im looking for feedback, since this is my first attempt at an exhaust. Please keep criticism CONSTRUCTIVE. Im not sensitive or anything, but useless comments are, well, useless...

Ive also never really seen it done this way and wondering if there is anything terribly wrong with running it under the diff. (or anything I did in general) anyone ever scrape that area of an exhaust?

ec17pse · 04-20-2012, 02:25 PM

So are you trying to keep the noise down or something by having that center extented! If so then it would yave been better to have a can before the muffler but If anything its going to reduce flow by hitting it and then being forced back up the chamber before going out the exit section!

Just re-read your ideas and what is this about a dump by the rear axle? Why would you want to do that way back there???

GSLENK · 04-20-2012, 02:30 PM

so move the dump further up? its back there to mainly keep soot and exhaust fumes well away from the cabin, undercarraige and such.

ec17pse · 04-20-2012, 02:34 PM

Quote:

Originally Posted by GSLENK

so move the dump further up?

I still dont fully understand what your goals are with this! Lol do you mean and open pipe with a butterfly section like the hotrods use? So you can close it then open it when you want! Is this what your meaning by dump???

GSLENK · 04-20-2012, 03:06 PM

yup. electronic dump valve this one Welcome to DMH Performance!

Im gonna cut like 3-4 inches off of the end of the 3 inch tubing (for clearance etc) then put one of those bad boys on. closed, it will be streetable and open it will be monster. (and fast open)

92 GSR-4 · 04-20-2012, 03:29 PM

I think it will accomplish what you want, but you could have added a small "Y" after your 45* bend (right after the diff) and put the electronic dump valve there. I'm not sure of the heat characteristics it might cause from running the exhaust right under the diff, if any, or if it will affect the diff in any way.

tkelly27 · 04-20-2012, 03:44 PM

E cut outs never seem to seal properly. For your safety you'll want to run a dump tube to the rear or side of the car from the cut out. You'll also want to move it as close to the turbo as possible. This will give you the least back pressure. If you insist on having the dump under the car, put it after a catalyst so you can at least reduce the possibility of carbon monoxide poisoning. I've dumped under the car with a similar electric cut out and found even with it closed I would get sick on anything longer than short trips. Open it would really mess with me. I currently have a pipe off the valve to the side of the car and I leave it open all the time with no issues. Fast is fun, being awake while going fast is much more fun : D

You did a good job putting that together, I look forward to seeing it completed.

GSLENK · 04-21-2012, 10:21 AM

The fail was in the spark plugs/wires. I will bolt it back up to check out if it feels any faster.

I really couldn't find any "easy way" to route the exhaust to the side (I would love a bumper dump...)

I also dont have space to dump the cutout at the rear, but have the cutout at the front... I dont see how 3" before or after makes a diff. Its 3" all the way.

Thanks for the heads up on Carbon monoxide poison warning. Im ready to order my cutout now that I found where the problem really was.

GSLENK · 06-06-2012, 08:17 AM

FINALLY I got the DMH cutout in. It was a PITA getting in contact with the guy, but once you get a hold of him, its all great service from there. Excellent looking piece. heres the end result. Im gonna pull it, and finish all the welds, then take a vid.

All done... Just need to take another day to weld all the holes in the exhaust, then it will be perfectly quiet.

The button goes in the factory spot top left above the inside dimmer, in an old blank switch plug.

DSM exhaust cutout 3" - YouTube

GSLENK · 06-09-2012, 11:53 AM

And the switch mounted in the car...

honda_burner · 06-09-2012, 12:22 PM

Quote:

Originally Posted by 92 GSR-4

I think it will accomplish what you want, but you could have added a small "Y" after your 45* bend (right after the diff) and put the electronic dump valve there. I'm not sure of the heat characteristics it might cause from running the exhaust right under the diff, if any, or if it will affect the diff in any way.

2g's run aftermarket exhaust around the rear diff with little to no problems. shouldn't be a big deal I wouldn't think.

DROPthatCLUTCH · 06-09-2012, 12:33 PM

Damn thats pretty sweet man well done!

clbailey · 06-09-2012, 01:01 PM

Looks good and im sure it flows, but sounds like assbutt.

T is for TURBO · 06-09-2012, 01:10 PM

Quote:

Originally Posted by clbailey

Looks good and im sure it flows, but sounds like assbutt.

Sounds just fine to me?

94_TSi · 06-09-2012, 01:14 PM

When i did my exhaust i did it similiar to yours, by running it under the diff it allowed for no bends other than to shoot it out where the stock muffler goes through the bumper. I didnt bend mine back up like you did, i just angled a straight piece of pipe up once agian for no bends. Only issues i have had are when you lay into it and the car squats it layed some sparks until it squared the exhaust off.

GSLENK · 06-09-2012, 01:16 PM

Quote:

Originally Posted by clbailey

Looks good and im sure it flows, but sounds like assbutt.

lol. I dont care what it sounds like, as long as WOT is evil, and cruising is dead silent. Mission accomplished.

I do agree with the assbutt. Most of the time it is pretty mean/terrible. But there are a few sweet spots.

Quote:

Originally Posted by 94_TSi

When i did my exhaust i did it similiar to yours, by running it under the diff it allowed for no bends other than to shoot it out where the stock muffler goes through the bumper. I didnt bend mine back up like you did, i just angled a straight piece of pipe up once agian for no bends. Only issues i have had are when you lay into it and the car squats it layed some sparks until it squared the exhaust off.

I haven't laid into it hard enough then. I do go extra slow over speed bumps though. I took the extra effort to make some smooth transitions to the oem muffler so I at least see some performance gain with the cut out closed.

Bud92gsx · 06-09-2012, 02:23 PM

I'm not going to give you crap, but I do have a question.

Did you buy the bends, bent or did you have them bent?

Mitch41 · 06-09-2012, 02:52 PM

Quote:

Originally Posted by Bud92gsx

I'm not going to give you crap, but I do have a question.

Did you buy the bends, bent or did you have them bent?

They look crush bent to me... But could be my eye.

GSLENK · 06-09-2012, 03:00 PM

Quote:

Originally Posted by Mitch41

They look crush bent to me... But could be my eye.

wrong x2

with this place only 30 mins from my house, I couldn't refuse. I bought them bent. http://www.mandrelbend.com/
ALL mandrel bends, from 180* U bends, I just cut/welded it myself.
The crush was a mean speed bump before I put the e-cutout on. I see what you mean, I think.

What is this crap you speak of? it can only improve V2 next time... do tell, unless it was about crush bends.

94_TSi · 06-09-2012, 03:02 PM

I haven't laid into it hard enough then. I do go extra slow over speed bumps though. I took the extra effort to make some smooth transitions to the oem muffler so I at least see some performance gain with the cut out closed.[/QUOTE]

With a stockish car and decent suspension you shouldnt have an issue.

Bud92gsx · 06-09-2012, 04:01 PM

Quote:

Originally Posted by GSLENK

What is this crap you speak of? it can only improve V2 next time... do tell, unless it was about crush bends.

Nope,not on the bends at all.It's your exhaust bro,and you like it.You could have saved a headache and money.

There was a thread a couple years ago about this.And since then these cutouts have blown up..They were huge on vdubs, and now you see this on alot more than vdubs.

So no I will not give you crap in public.

But I do love the cutouts. You can do a basic electric one like this with a switch.OR a boost activated cutout. Both work the same way, they open. You can't get anymore simplified than that.

GSLENK · 06-09-2012, 04:53 PM

Quote:

Originally Posted by Bud92gsx

Nope,not on the bends at all.It's your exhaust bro,and you like it.You could have saved a headache and money.

There was a thread a couple years ago about this.And since then these cutouts have blown up..

But I do love the cutouts.

Your being a bit vague. I have a total of 370 in everything new past the o2 housing. a good used TBE is about 350. so i could have saved $20. I def could have rerouted it so that I can speed over speed bumps = a small headache. so yes you are somewhat right.

I did a lot of searching, on here, and LSx car forums. I only saw happy responses for DMH, terrible responses to QTP. I would never seek advice from vdub owners, no offense, but if they put the rest of their car together the same way they put their wheels on...

Bud92gsx · 06-09-2012, 05:49 PM

Ha ha ha damm vdub owners.. Nah man thats not what I'm saying at all.I wanted to keep this conversation private, cause I did not want to nit pick publicly.

But you got your hands dirty, had some fun, and made this.So Cudos to you sir.

A cutout can be used on a stock exhaust, to give you the flow you want, and keep the rest stock.

If you go 3 inch turbo back, a cutout at the back axle in this case.It's more than overkill.

You basically threw money away doing it this way..What did the DP and piping cost to the cutout? Thats how much money you threw away. But my personal opinion does not matter here.I'm just cheap, so don't mind me.

There are so many ways to do exhaust. Go 3 inch turbo back and call it a day.
3 inch DP, put cutout before or after cat, keep the rest of the exhaust stock.
2.5 turbo back and stay semi stock, with a deeper tone, and more than stock potential for some added HP.
2.5 turbo back, with cutout.
Bumper side exit exhaust.
Side exit where the vents are on the 1g before the rear tire.
Cat back, and call it a day.

The possibilties are almost as endless, as what to have for dinner.

GSLENK · 06-10-2012, 08:06 AM

OOOOOOOO ok I see what you mean.

Well I had thought about cutouts in various areas...

DP first bend, not enough clearance

Test pipe area, not enough clearance

Rear, enough clearance

Choice was pretty easy. Also I didnt want exhaust all under my car. If I could do it again... (And I think I will) I would route the cutout from the DP and dump it in a front side bumper exit, leaving the stock exhaust on.

Also... with my setup I get a little better performance over stock with 3" almost all the way back.

Bud92gsx · 06-10-2012, 09:58 AM

This is true. True indded. But u will have a louder sound when just druising with the 3 inch basically all the way back..

But still... You made this..So throw form and function out the window, because its homemade... It always tastes better when its made with plenty of love.. Yes i threw in a food ananolgy.