Supertrapp dyno tuning?

[zzwhm]

Has anyone done dyno tuning with supertrapps to optimize the number of discs for a 3.2? I'm running stock with SSIs and looking for a starting point.

Supertrapp website says no discs has the most backpressure and adding discs decreases it and leans things out. It's counter intuitive to me, but I'm no engineer.
Bill

[earlyapex]

The discs push the end plate further away from the pipe opening so the more discs you put in equates to a larger exhaust opening and reduced back pressure.

I also interested to see if supertrapps can get my car under the 92 dB limit as Laguna Seca.

[analogmike]

Check my web site for torque curve charts, I tested supertraps. The only way they will work is to remove the end cap (sort of a mellow megaphone setup - LOUD). They are useless on a 911 with few enough disks to reduce the sound enough. Today I ran an autox and got 95 or 97 dB with enough disks to run reasonably well in the 2.7RS and went home early (90 dB limit).

[earlyapex]

Mike, thanks for the information! You've saved me some money and allot of aggravation.

Has anyone run the following system, which appears to be a pair of Phase 9's dumping into a sport muffler?

[zzwhm]

Mike -
Thanks for sharing your dyno info. When you ran the supertrapps without an endcap how many discs did you have on?

My motive is weight loss at the rear of my F Class 3.2. If I get a setup that is as good as what I'm running from 4K upward I'll be happy just to lose a few lbs. And if it's better that's a bonus.

You mention cam timing in your narrative on the dyno runs. Have you done testing of this such as comparison between mid-spec and retarded?
Bill

[analogmike]

Hi,

When you remove the end cap, there are no disks, it's totally open. Power is quite good and weight quite low but also quite loud (100 dB?)

The Phase 9 system above is the complete phase9 system with custom muffler, it is VERY poweful and VERY VERY quiet. Maybe the best setup you can get for tracks around or below 90dB. Price is expensive but worth it, for the performance.

you can tune your torque curve with cam timing, very track-dependant though so no best setting.

[earlyapex]

Thanks for the great information. The Phase 9 system looks like a very nice solution to those of us that run significantly noise restricted tracks (i.e. Languna Seca). I pulled the picture from Bead Form and Quiet Horse Power site. Unfortunately, my budget will not allow me to go this route just yet. Let's hope Santa Clause is nice to me this year.

[zzwhm]

That phase 9 looks like it's hooked up to one of mb911s mufflers.
Bill

[Dleong]

I ran Supertrapps with 10 discs, and the endplate installed at Laguna. (3.0 SC engine) I got mostly 92db, with one 93db. (I try to ask for my db chart when I go to Laguna.) Since this exceeds the 90db often required, and too close to the 92db of that particular day, I stopped using the supertrapps at Laguna.

I once ran with new packing, and 6 discs, but it seemed like the exhaust was overheating, based upon the warpage, and discoloration. I didn't get any sound readings that day, and never tried it again.

Since that day, I switched to the stock muffler until it broke the last time I was there, and haven't been back since.

[ttweed]

Originally posted by zzwhm
That phase 9 looks like it's hooked up to one of mb911s mufflers.

No, the Pete Weber/Phase 9 crosschamber is similar in design to mb911's in that it is a cylindrical, welded tube, but the inlets are in different places (more outboard) on the Phase 9 setup. The dual inlet mufflers from mb911 connect to stock headers or heat exchangers.

I have the Phase 9 setup on my 3.4 carb'ed motor and it works very well indeed. I am under the 92db limit for Laguna Seca running with the crosschamber. For non-sound-limited venues, I remove the crosschamber muffler and have a straight-pipe extension setup that I bolt directly to the Phase 9 mufflers. It is probably around 100db that way, although I haven't measured it.

BTW, Pete Weber used to make these in mild steel, which was much less expensive, since now they only come in SS @ about $3400 for the complete system. I had my mild steel ones ceramic coated for $150 and they have held up very well.

TT

[earlyapex]

I spoke with Pete this morning and each exhaust system is a custom job. I'll have to explore his system as I do not want to give up running Laguna Seca and I don't want to slap on a goofy set of turn outs. They've have unfortunately begun using a roving sound meter so you can be zapped at any spot on and off the track.