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-   -   Has anyone driven to the muffler shop w/straight headers? (http://forums.pelicanparts.com/porsche-911-technical-forum/178897-has-anyone-driven-muffler-shop-w-straight-headers.html)

efhughes3 08-22-2004 03:45 PM

Has anyone driven to the muffler shop w/straight headers?
 
I'm planning my B&B header install. I'm either going the Fabspeed kit route or have a Flowmaster system made up. Either way, it has to go to the shop for welding.

Would driving (7 miles) to the muffler shop w/ straight headers be an issue? I'm guessing a lot of heat would get dumped into the area in front of the bumper.

beepbeep 08-22-2004 04:02 PM

hehe...i drove my daily driver (front engine 4-cylinder) to the parts shop w/o any downpipe, just short cast-iron header straight into the engine bay.

Nothing happened but it sounded like an airplane.

I also started my 930 w/o headers, you could see small flames coming out :D It made a lot of noise :)

My educated guess is that absolutely nothing will happend, bar the possibility that you get in trouble with law for excessive noise.

Grady Clay 08-22-2004 04:19 PM

Ed,

Duct the heat elsewhere. I drove to the shops (and around the State Capitol) with a Bursch two-into-one straight pipe (about as loud as you can get at 7000+ WOT.)
I was even cited at an SCCA party by some Volvo matron for passing her on the road from Aspen to Snowmass.

Best,
Grady

BTW, I parked my 911 next to the judge's XKE. I had had the Mayor of Aspen as passenger and witness. Guess what the result was.
G.

Dantilla 08-22-2004 04:33 PM

I hit a bump on a mountain pass back when I had an old 924 and busted the exhaust off right behind the collector.

After it cooled, I stuffed it inside the car (passenger floorboard to rear hatch), and drove home.

A rediculous amount of noise whenever on the gas. Glad it was coming back down from the mountains. The muffler shop said they could hear me several blocks away when I went to get it welded back on.

I kept the RPMs as low as possible, and had no trouble with the law.

Still don't want to do it again, though.

masraum 08-22-2004 06:25 PM

It's kind of fun, and sounds really, REALLY cool, but it could cause trouble. It's really loud. Have you ever been to a drag strip? That's the sound, more or less. Did I mention it's loud?

Jay Auskin 08-22-2004 08:18 PM

I had a '78 Buick LeSabre and the exhaust fell off once. Good times I tell ya!! Drove with it for a few weeks until I was able to get it fixed. Sounded pretty cool, but there was a horrid resonnance at ~40MPH that was unbearable.

efhughes3 08-23-2004 07:06 AM

Well, if I go this route, I was going to do it early in the morning. Good for avoiding cops (perhaps), bad for the neighbors. I'm really concerned about the heat and potential damage than the noise.

Maybe I'll have it towed over, but I screwed up my rear valance a bit going onto the wrecker when I lost a tire at the last DE.

Rot 911 08-23-2004 07:11 AM

Ed you won't hurt anything engine wise due to no muffler.

TRE Cup 08-23-2004 09:47 AM

keep it below 3500 rpm and 1/2 throttle- no problems at all (providing no law around) we do it all the time when getting exhaust work done

efhughes3 08-23-2004 10:41 AM

Thanks Guys!

MotoSook 08-23-2004 11:13 AM

I've driven with just a pre-muffler :) Love the noise...and if you do it in the dark....get some RPMs and lift off the throttle...it'll be a nice flame show for the car behind you :D

Amac 08-23-2004 12:15 PM

Ed,
Drive it over, you'll be fine.
The exhaust and heat should'nt
be a problem.
Bet it sounds great.
Supertraps?
Like to hear the story about the
lost wheel.

juanbenae 08-23-2004 12:17 PM

what was the question??? im having a hard time hearing you......

Grady Clay 08-23-2004 12:49 PM

One thing I thought I should add here; don’t drive without some headers. With the exhaust ports open to the atmosphere, the valves can cool tool quickly after shutoff.


I tried this with the 4-5-6 side off on a mule 2.2T on the dyno and a Bolex 16 mm camera trying to see in the combustion chamber when the exhaust valve was open. Didn’t work, too much flame. Under load the exhaust valves look like a turbo red heat.
In this case there was no damage but I sure worried about it. After cool-down and shutoff, I kept cranking on the dyno starter to insure all the valves continued to contact the seats.

Talk about loud!

Best,
Grady

tobluforu 08-23-2004 01:01 PM

I've driven a few cars with open headers to the muffler shop. It was fun when I was 16, now it's a little to much. I must be getting old or something. Go for it, just pull over and shut the motor off if a cop is in the area. Where I live, you will get a ticket if car is too loud.

efhughes3 08-23-2004 01:12 PM

Grady: I heard about the cool air/valve thingy a number of years ago. Not personally, but it made sense when I heard it. I can honestly say that I've never ran a car without headers in 30+ years!

Grady Clay 08-23-2004 01:26 PM

Christophorus 309 came today.
Here is a 997 on the engine dyno,
obviously at full throttle.
You can see what I’m talking about.
What do you think the exhaust valves look like?
"
http://forums.pelicanparts.com/uploa...1093292346.jpg "
(C) 2004 Dr. Ing. h.c. F. Porsche A.G.

Best,
Grady

TRE Cup 08-23-2004 01:37 PM

good advice for engines being run hard on a dyno, but the guy was just asking about a trip to the muffler shop. besides that, when was the last time you saw damaged valve train from open headers? Not likely to happen anymore: modern metallurgy (production valve train) coupled with better induction yields far more robust parts. When was the last time you saw a race team stuff rags in the exhaust after a run? 40's, 50's?? he he

Grady Clay 08-23-2004 02:12 PM

I agree; I only posted the addendum so someone didn’t misinterpret that it was acceptable to run with no headers at all. It isn’t. Last time I saw it was 20+ years ago when I did it on the dyno.

On the track and on the dyno, I take the cool off very seriously. I make sure the engine and brakes are sufficiently cool to stop in one position. No, I don’t use rags in the intake and exhaust (anymore.) I did with 587/3 engines where you can look down the carb and inspect the inside of the exhaust pipe.

The closest thing these days is the nitromethane-methanol burning dragsters. They rebuild after each run

Yes, I know Ed just wants to drive 7 miles for some welding and not burn the paint on his bumper. I just use these threads to offer my lame 2c of experience.

Best,
Grady

TRE Cup 08-23-2004 02:14 PM

not lame at all grady- quite sage in fact!


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