Mild steel for a 3" turbo exhaust?

PercentSevenC · 08-11-2008, 12:40 AM

How does it sound? I haven't had good results from normal-thickness mild steel exhaust piping on NA rotaries. It always comes off sounding tinny and droning and stupid. However, that was always with 2" OD pipe and no turbo to tame the exhaust pulses. Is 3" OD 16-gauge mild steel feasible for a turbo exhaust system?

Also: I'm planning on running one of Racing Beat's universal presilencers and a Borla ProXS. Will that be headache-inducingly loud?

Boostmaniac · 08-11-2008, 07:38 AM

Expect the mild steel to rust ungodly fast.

If you are using it for a downpipe also, expect failure down the line also due to heat and rust. I have always used stainless for the exhaust plumbing on rotaries with no issues.

I'd say it is worth a shot if you already have it, just make sure it is welded good.

The muffler combo you mentioned should sound reasonable, those presilencers are pretty dope.

PercentSevenC · 08-11-2008, 04:22 PM

Quote:

Originally Posted by Boostmaniac

Expect the mild steel to rust ungodly fast.

If you are using it for a downpipe also, expect failure down the line also due to heat and rust. I have always used stainless for the exhaust plumbing on rotaries with no issues.

I'd say it is worth a shot if you already have it, just make sure it is welded good.

I don't have it yet. I'm just trying to shave every penny I can off this build.

I just wish 304 stainless bends weren't so expensive.

I will be sure to spray it with high-temp exhaust paint. They don't salt the roads here, either. I guess mainly I'm worried about the pipe ringing and sounding like crap.

Quote:

Originally Posted by Boostmaniac

The muffler combo you mentioned should sound reasonable, those presilencers are pretty dope.

Cool. That's good to know.

85rx-7gsl-se · 08-11-2008, 08:36 PM

I am running just plain tubing with a 3" Racing Beat downpipe to a 3" Borla dropping to 2.5" over the axle with a 2.5" Supertrapp tip and after about a year, the exhaust is starting to burn out and its decently loud. I like it, but it draws alot of attention. I am running a Streetported 13BT with a BNR S5 Stage 1.

PercentSevenC · 08-12-2008, 12:48 AM

Wow, it's already burning out? Is the Borla losing its packing, or is it the Supertrapp tip or both?

Based on the responses I've gotten from this and the other forum, I think I'll go ahead and try it. It'll be an experiment, like so much of the rest of this build.

85rx-7gsl-se · 08-12-2008, 12:54 AM

Not sure, just know it have gotten louder

Ran the Supertrapp cap and fins for a while and then took them back off, think the extra backpressure and heat may have led to premature burn out :?

Phoenix7 · 08-12-2008, 01:19 AM

Don't cheap out man. It's not worth it in the long run. Wait longer and get the better material.

hIGGI · 08-13-2008, 12:55 AM

both my downpipe and manifold on GT35R is mild steel, i just had it aluminium coated once it was welded together and its lasting with no problems for 3 or 4 years now.....

http://rx7cz.net/photos/workshop73/

Boostmaniac · 08-13-2008, 02:33 AM

Standard mufflers won't take the heat from our turbo rotaries, it is just a fact of lie. Sonce you are using the RB presilencers, man up and get the Y pipe and two RB mufflers. It will be VERY streetable and will last for a dickyear.

For those not in the know, dickyear means a very long time.

It's extra money now, but less since you'll probably end up replacing parts due to premature failure.

PercentSevenC · 08-13-2008, 11:20 AM

Borlas are fine. They're 304 stainless on the outside with stainless and ceramic wool packing. It'll last. (And even if it doesn't, they have a million-mile warrantee.

) Oh, and I should mention this is actually for an FB, but I figured you guys would have more information on turbo exhaust systems. I suppose I could get just the right RB muffler, but for that price I could buy three Borlas and have cash left over.

I really appreciate all the opinions. So, it sounds like I'll be using either aluminized mild steel or 409 stainless if I can find some cheap straight lengths. Either way it should last a while as long as the welds are good.

Boostmaniac · 08-14-2008, 11:50 AM

Wait, is this for a turbo FB?

Single side exhaust will be slightly louder, and the ceramic wool should last, it might get a little louder after a bit, but the usage of ceramic wool is pretty dope. I'd say give it a shot.

Max777 · 08-17-2008, 08:03 PM

Quote:

Originally Posted by Boostmaniac

Standard mufflers won't take the heat from our turbo rotaries, it is just a fact of lie. Sonce you are using the RB presilencers, man up and get the Y pipe and two RB mufflers. It will be VERY streetable and will last for a dickyear.

For those not in the know, dickyear means a very long time.

It's extra money now, but less since you'll probably end up replacing parts due to premature failure.

That's what I'm thinking of doing...

I have a header already, since the two pre cats failed and are NOT coming off of the stock manifold, then I have my clogged cat, which is getting replaced with a RB presilencer (hopefully before my car sees the road), and then I have a shitty 2.5 pipe that goes out to a glasspack that is prolly burned out by now...

The shitty pipe and glasspack are gettinr replaced with RB shit as well hopefully soon, and if not, it will be 2.5 SS pipe to an HKS Hi-Power muffler.

08-11-2008, 07:38 AM	#2
Boostmaniac Rotary Fanatic Join Date: Apr 2008 Posts: 182 Rep Power: 0	Expect the mild steel to rust ungodly fast. If you are using it for a downpipe also, expect failure down the line also due to heat and rust. I have always used stainless for the exhaust plumbing on rotaries with no issues. I'd say it is worth a shot if you already have it, just make sure it is welded good. The muffler combo you mentioned should sound reasonable, those presilencers are pretty dope.

08-13-2008, 12:55 AM	#8
hIGGI Rotary Fan in Training Join Date: Mar 2008 Location: Czech Republic Posts: 78 Rep Power: 18	both my downpipe and manifold on GT35R is mild steel, i just had it aluminium coated once it was welded together and its lasting with no problems for 3 or 4 years now..... http://rx7cz.net/photos/workshop73/

08-13-2008, 02:33 AM	#9
Boostmaniac Rotary Fanatic Join Date: Apr 2008 Posts: 182 Rep Power: 0	Standard mufflers won't take the heat from our turbo rotaries, it is just a fact of lie. Sonce you are using the RB presilencers, man up and get the Y pipe and two RB mufflers. It will be VERY streetable and will last for a dickyear. For those not in the know, dickyear means a very long time. It's extra money now, but less since you'll probably end up replacing parts due to premature failure.

08-14-2008, 11:50 AM	#11
Boostmaniac Rotary Fanatic Join Date: Apr 2008 Posts: 182 Rep Power: 0	Wait, is this for a turbo FB? Single side exhaust will be slightly louder, and the ceramic wool should last, it might get a little louder after a bit, but the usage of ceramic wool is pretty dope. I'd say give it a shot.