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Exhaust Straight Pipe

 
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Who runs a straight pipe exhaust system?
I run a straight pipe all the way from the headers to the tip
11%
 11%  [ 3 ]
I run a straight pipe from the headers followed by the final muffler
48%
 48%  [ 13 ]
I run a stock setup
37%
 37%  [ 10 ]
No exhaust at all
3%
 3%  [ 1 ]
Total Votes : 27

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elitejaso  



Joined: 24 Jul 2007
Posts: 138
Location: Melbourne

PostPosted: Mon Mar 31, 2008 12:04 am    Post subject: Exhaust Straight Pipe Reply with quote

After about a month of driving around with a rattling exhaust i finally decided to take action.

I'd been under the car before and all the mounts were in excellenct condition.
However the initial muffler which was no longer stock that had been installed by its previous owners was coming apart at the dodgy welds they had attempted.

So yesterday i took some measurements went down to my local muffler shop and picked up a 1.5m steel tube (which they so kindly bent 15 degrees for me) and a clamp for $25 (the cheapest parts i had bought for this car for quite some time

Today i decided i was going to put the hours in and install this sucker. I took the initial muffler section out by disconnecting the flange and then with an angle grinder cutting through the other end of the pipe.

With the old section out i ran some measurements to the new pipe and cut it accordingly. I decided to keep the original flange so i cut it off the old piece and welded it onto the new tube. I slotted the end of the new tube and then was ready for fitment.

It all went together quite smoothly welded an old mounting bracket back on to the new tube and then started her up.

The car was a bit louder than before (to be expected) but was sounding great. Took her for a 5min spin and the car felt awesome. The engine roared from 3000rpm up and i couldn't believe the difference it made. There was no noticable loss of acceleration and the gain of high end torque (pulling power) puts me in my seat.

I definatley recommend installing a straight pipe (for 924 turbos) to replace the initial muffler if you cant afford a perfomance exhaust.

Heres some photos of my finished work to anyone whos interested.
And i've added a poll just to see how many of you guys run a straight pipe
system.











Jason
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924RACR  



Joined: 29 Jul 2001
Posts: 8321
Location: Royal Oak, MI, USA

PostPosted: Mon Mar 31, 2008 12:19 am    Post subject: Reply with quote

Deleted the extra thread for ya...

I'm running completely stock exhaust, but one day will probably open things up... have to do the Megasquirt, boost controller, and IC install first, though!

PS - nice 356 hiding in the background there!
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Vaughan Scott
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'79 924 #77 ITB racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype
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Vince Ponz  



Joined: 02 Nov 2002
Posts: 3581
Location: Florida

PostPosted: Mon Mar 31, 2008 1:15 am    Post subject: Reply with quote

Straight pipe with a suppertrapp at the end. Small straight thru tip. I do not use the plates that you can put on from one to 10. Open all the way is the best. Not loud especially with the additional suppertrapp.
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gegge  



Joined: 27 Jul 2007
Posts: 1077
Location: Sweden

PostPosted: Mon Mar 31, 2008 4:37 am    Post subject: Reply with quote

Straight pipe with a 15 disc supertrapp muffler. "Snuff 'R Not" endcap from White Brothers makes it possible to run a complety open system.
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Carl Fredrik Torkildsen

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elitejaso  



Joined: 24 Jul 2007
Posts: 138
Location: Melbourne

PostPosted: Tue Apr 01, 2008 8:54 am    Post subject: Reply with quote

Cheers for cleaning up the thread RACR

IC (probably front nose installation) is up there on my list of things to do.
Also would love to install a 944 gearbox as im not a big fan of the dog leg box for everyday driving.

Yeah good pick up its a 356 convertible D in the background, but it doesn't compare to the 924
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simsport  



Joined: 06 Nov 2002
Posts: 573
Location: UK Warrington

PostPosted: Tue Apr 01, 2008 9:46 am    Post subject: Noise Reply with quote

The big advantage the turbo cars have is the sound suppression a turbo delivers. My supercharger pushes a lot of air through the system and even with a 3ft cherry bomb and a twin outlet Vento box at the back I get 103/104DB.

If I fit the 4-2-1 I reckon I will struggle to keep below the 106db limit for the uk events.

Cheers
Simon
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pocketscience  



Joined: 23 Apr 2006
Posts: 1650
Location: Sydney, Australia... mate!

PostPosted: Tue Apr 01, 2008 11:55 am    Post subject: Reply with quote

924RACR wrote:
PS - nice 356 hiding in the background there!


Was gonna say that too! Looks like a winner - got a proper pic of it? A 356 is on my list of future projects!


G.
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emoore924  



Joined: 13 Apr 2004
Posts: 2801

PostPosted: Thu Apr 03, 2008 12:11 pm    Post subject: Reply with quote

Bursch 4-2-1 into a straight pipe into a supertrapp.

l-o-u-d with the disks.

s-c-r-e-a-m-i-n-l-o-u-d without them.

Mmmmmmmmm, good
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Vince Ponz  



Joined: 02 Nov 2002
Posts: 3581
Location: Florida

PostPosted: Fri Apr 04, 2008 1:12 am    Post subject: Reply with quote

emoore,

I did the same and it was too loud. At the trap great but I would drive to the track therefore I had to remove it. Kept the 4 2 1 and put on a muffler. Still loud but bearable.

Vince
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morghen  



Joined: 21 Jan 2005
Posts: 8177
Location: Romania

PostPosted: Fri Apr 04, 2008 3:35 am    Post subject: Reply with quote

i bet the 931 sounds mean with straight pipes. I have a stock setup wich i'm happy with...as it is sporty but not loud. however it kinda sounds...umm...gayish for a sports car....so i'm thinking of geting a mean ass subaru style sound exhaust that burbles and wooshes when WOT...but i might hate it on a long term.
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emoore924  



Joined: 13 Apr 2004
Posts: 2801

PostPosted: Fri Apr 04, 2008 2:14 pm    Post subject: Reply with quote

The 931 is q-u-i-e-t with straight pipes. The turbo diffuses all the noise.

The n/a f'n r-o-c-k-s with a 4-2-1 and straight pipes. I put about 12 disks on for getting to the track, then take them off for the weekend and run an open pipe with the supertrapp 24x4" glass pack, unless I'm at Lime Rock, of course. Then you have to run a muffler all weekend.
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ideola  



Joined: 01 Oct 2004
Posts: 15505
Location: Woodstock IL

PostPosted: Fri Apr 04, 2008 8:35 pm    Post subject: Reply with quote

Speaking of Lime Rock, Frank said he's going to be running his D-prod there in the club race later this month.

I have a 944 sport exhaust on the 924S, along with a glass pack, and it's kind of annoyingly loud in the passenger cabin after long term driving, but it sounds pretty good driving by!
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924RACR  



Joined: 29 Jul 2001
Posts: 8321
Location: Royal Oak, MI, USA

PostPosted: Fri Apr 04, 2008 10:15 pm    Post subject: Reply with quote

I can't stand the way Supertrapps sound. I had one on my racecar initially, when I started.

Now I'm running the MSDS header (pretty similar to the Bursch) with 2.5" pipe throughout, and 3 inline Dynomax race bullet mufflers - 2 in the center tunnel, one at the rear stock muffler position. Loud, yet actually a little on the quiet side for most racecars, since the sound limit at my home track is VERY tight - 74db on the back straight (most tracks are 95-105). Very unpleasant in the car, but the complete lack of soundproofing doesn't help either!

Of course, it sounds awesome, lots of nice base.

If I remove the rear-most muffler (as I do at the big tracks with the higher sound limit), it picks up a very nice mean-sounding rasp.

I can also install a large, heavy oval muffler at the rear, which is VERY quiet, makes it streetable and hardly audible on track.
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Vaughan Scott
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'79 924 #77 ITB racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype
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mr. dude  



Joined: 14 Feb 2008
Posts: 111
Location: Michigan

PostPosted: Wed Apr 09, 2008 10:48 pm    Post subject: Reply with quote

I say delete the cat. Use a straight pipe but keep the muffler.
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TOM087  



Joined: 19 Jun 2007
Posts: 73
Location: Hobart, Australia

PostPosted: Wed Apr 16, 2008 11:08 pm    Post subject: Reply with quote

I had a thin weld for a few days before the final muffler and i loved it!
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