Race Car Exhaust

[Daily02]

You spent all that money building all that power... 

 

A muffler could be in place of the resonator, and another in the stock location, plus a large case Walker Super Turbo where the license plate was. Try the mufflers Steve K. recommends he's got the job done before, and it can be done again.

 

Another thing is just give up Laguna except for when Speed Ventures or Shelby Club has a Loud day. 

 

Regards

 

Dono

[TobyB]

Quote

give up Laguna 

...and live half a life, not a whole.

 

Fitting two mufflers is far more appealing.

 

t

 

[Tommy]

I split my F20C exhaust to twin pipe after the resonator and fitted large muffler to each. I ran them right and left far apart with a theory that it halfs the desibels coming from one pipe Over here measurements are mostly done stationary 1m to the side from exhaust exit so the other exit is left further from the dB-meter. Well - I don't think it's as effective as I thought but has worked for me so far.

[Ian]

For a race car or track car, I think the best route is to cut out the spare tire well and use the space to run a large case straight-through muffler.  If you size the muffler you shouldn't have decreased flow, and you can even get aluminum mufflers from Vibrant to cut weight at the rear of the car.

[visionaut]

What a beast indeed, Mark…

 

I’m having a little difficulty deciphering these exhaust notes on the test sheet, particularly the info at the ends of two lines:

 

HEADERS: 1 7/8 X 3-2 X 24

> 1 7/8” primaries

> X 3-2x24  = ??

COLLECTOR: 2"X 6 4-1

> 2” diam x 6” collector

> 4:1 style

MUFFLER: EXTREME 16

> is Extreme16 a muffler brand/model?

TAILPIPE: TAPPERED 2 1/2-3 X 4 3X 40' 

> 2.5 or 2.5-3” diameter?

> -3 x 4 = ??

> 3X 40’ = ??

CHANGES ON RUN: SHORTENED PRIMARIES 4 1/2-5" 27" TOTAL

> primaries shortened by 4.5-5” to 27” length

 

Given they were testing header primary lengths, and noting the other exhaust info in your test sheet, I’m led to believe your full exhaust system was engineered. So it’s unlikely that your side-exit ‘collector extension’ was just a haphazard practical-fit add-on. Its optimal length might have been calculated.

 

Knowing what the optimum collector extension length is is useful because once you know that length, all the multiples of that exhaust valve to free-space distance will also work best, up to the full length of the exhaust system (mufflers and all, if not too restrictive ).

 

So for example if a 36” long header sees its optimum power with a 15” extension, then you know a 41” total length works best - but also that it’s multiples  82”, 123”, 164”, etc will too.. So you can use these length multiples to help design an alternative exhaust that also supports max power.

 

From the photos, the length of the extra-long side-exit ‘collector extension’ looks like it could be based on the second multiple of a typical shorter 1X ‘tuned’ length. ??

 

 

[markmac]

All good ideas, I need to save this thread to refer back to.  Funny enough I was looking at the CSRG event schedule.  David Love Vintage Races event at Sonoma Raceway (open/no restrictions), Laps for Laguna (Friday 105db, Saturday and Sunday - Open/no restrictions), Charity Challenge at Sonoma Raceway (open/no restrictions), Season Finale at Thunderhill Raceway (103db).

 

At the moment the trunk is pretty wide open.  I was going to build a 'replica' Alpina 100L flat tank, and I still may at some point.  The were essentially 'flat' and maybe rode 1" to 2" below the plane of the trunk floor. 

 

I may just fit in a tank that will function until I get to it.  We'll see on that.  I need to get the dry sump oil tank back in there, fuel pumps, fuel surge tank, alternator, battery....and back in the day they had one of the fire bottles (plumbed into the roll cage), overflow bottles for the oil tank and radiator....oh yea, they mounted the radiator in the back under the fuel tank.....there WAS alot going on back there.  The tank pictured is a 110L CSL tank, the 2002 tank was the same design only 100L, back in those days they were tanks (no fuel cell).

 

The path forward I think is to re-work the header and the side pipe, whether that be oval pipe or round.  Fabricate it in such a manner that would allow you to remove the section that goes out the side and then make a secondary section that attaches (where side pipe detaches) that has the various mufflers and or resonators.  There are probably some events you just couldn't go to depending on sound levels.

[2002iii]

What about a corvette style side pipe?

[markmac]

I was looking at this pic the other day, this is a mid 90's <1996> (holy sh&t) I'm old..... article from 'BMW Car' mag. when Alex Elliott de-barned the Alpina Gosser 3.2 CSL out of Italy.  That car has a header and a twin pipe 'muffler' on the end of it.  No question.  Good god that thing is just off the ground though = guessing not even 2".  Interesting.

[Preyupy]

We saw over 125dB at Laguna with this one.  The two 4" pipes coming out of the right side, aimed right at the microphone didn't help. An M49 at 8000 rpm WOT is REALLY LOUD 

[markmac]

What a beast that car is - I am surprised it wasn't louder than 125db (it probably was.....).  Short story, I was in Vasek's dealership in the late 1990/91(?), they had a MB 190e 16v I was interested in, low miles driven by some Hollywood dude up and down the hill to his studio.  I bought the car.  That there CSL was in one of the showrooms where I was signing paperwork, flat tires, pretty tired looking but I remember it well.  

 

The MB developed an expensive problem with one of the Cat's, I made it known they should make it right....salesman blew me off.  I wrote a letter to Vasek Polak.  His assistant called me up and told me to take the car to the shop of my choice and have it repaired, then send the invoice to Vasek Polak and they would reimburse me.  I did and they did.  Classy guy.  Incredible history.  Pre-internet, you had to call or write a letter.

[Preyupy]

It was a non sound controlled event (pre historics weekend)  and I saw there were people in the sound booth.  I knocked on the door and asked if they were taking readings?  She said yes but only because they were training new people, "we aren't busting anyone this weekend".  I asked if they had readings just so I could see what I might need to do if we came back on a sound controlled weekend.  She did have some and I gave her the group number and car number,  when she found it she just smiled and said "YOU WIN" I think it was 128db actually.  We were louder than the CanAM cars mostly because their pipes aim straight back and the Microphone isn't looking straight into the pipes.