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Posted by: drew365 Jul 25 2003, 03:58 PM

I dyno'd my car today. We did three pulls and the end results are SuperTrapps with 15 disks gave the most h.p., Magna Flow's were second and SuperTrapps with no disks was the weakest combo. Here's the numbers:

SuperTrapps w/ 15 disks: 196.5 h.p. @ 6600rpm
Torque 165.4 @ 5200rpm

Magna Flows: 188.6 h.p. @ 6450 rpm
Torque 165.8 @ 5200 rpm

SuperTrapps w/ no disks: 186.8 h.p. @ 6600 rpm
Torque 162.7 @ 5250 rpm

Air fuel ratio was about 14.7:1 with the SuperTrapps. Is this too lean? I screwed up and forgot to put some racing gas in the tank before I left the house so all the results are using 91 pump fuel.

Posted by: seanery Jul 25 2003, 04:07 PM

you have a 2.7, right? any mods? headers?

Posted by: Brad Roberts Jul 25 2003, 04:09 PM

Why did the MagnaFlow pulls stop at 6450 instead of 6600 like the other two pulls ??


B

Posted by: drew365 Jul 25 2003, 04:30 PM

The engine is a twin plug, electromotive crankfire ignition, 11.5:1 Mahle pistons, S cam, stainless steel headers w/o heater crap.
We ran all the dyno's to 7k. The rpm that I posted is where the h.p. peaked. It stayed pretty level from peak to 7k.

Posted by: garyh Jul 25 2003, 04:47 PM

14.7 is minimum emissions.
13.2 is maximum power

Posted by: Jeroen Jul 25 2003, 05:21 PM

The max torque is pretty high up in the rpm range. How's the torque curve?
Can you post the graphs from the dyno?

cheers,

Jeroen

Posted by: drew365 Jul 25 2003, 05:47 PM

I'll try to scan the graphs and post them over the weekend. I'll have to request time on my wifes scanner. The torque bottoms at about 139 @ 4600 rpm and climbs to 165 @ 5250 rpm and then starts to slowly drop off.

Posted by: TimT Jul 25 2003, 07:13 PM

flat torque curve is cool.... you would prefer a rising torque curve, but you dont want a torque curve that peaks then falls to zero....

Posted by: ChrisReale Jul 25 2003, 10:08 PM

Poor you!

Just kidding. How loud is the Supertrapp with fifteen disks?

Posted by: Qarl Jul 25 2003, 10:10 PM

Schweet dude... and that's rear wheel horsepower too....

Wonder what the power is at the flywheel? Woohoo!

Posted by: ! Jul 25 2003, 10:37 PM

Interesting,,,,,I always thought I had less oomph all around with no discs....thought I was going or getting MORE bonkers....

Posted by: Jeroen Jul 26 2003, 04:42 AM

Mikey, that does make sense... compared to a stock setup
Lack of backpressure will cause a drop in torque in the lower rpm range (which is where you experience the "oomph")

cheers,

Jeroen

Posted by: drew365 Jul 26 2003, 08:47 AM

I recounted the SuperTrapp disks now that they are off the car and there are 18. The sound in the upper rpm range is nice but it is much quieter than the Magna Flows are. On the street the Magna Flows set off alarms constantly, good cheap thrill.

Posted by: ! Jul 26 2003, 09:38 AM

The guy that built my 3.6 conversion claimed an extra 8 hp w/o discs on the dyno. Iwas unable to feel any diff when running un corked. That's why I made that comment.

There is LOUD and too fucking loud......I would rather hear my shifts than have to wear earplugs on the track and watch the tach ALL the time....

Posted by: drew365 Jul 26 2003, 05:15 PM

I'll see if I scanned the graphs right so they can be posted. The first is SuperTrapps with the recounted 18 disks. The guy printed a test run and the first run together so that's why there's double lines. The air / fuel ratio didn't pickup on this one through the disks.


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Posted by: drew365 Jul 26 2003, 05:17 PM

What do you know, it worked. The second is SuperTrapps with no disks.


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Posted by: drew365 Jul 26 2003, 05:18 PM

Third pull was with the Magna Flow mufflers.


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Posted by: drew365 Jul 28 2003, 06:05 PM

Can someone tell me by looking at the second and third graphs what my air / fuel ratio is? I don't know if it's the peak which appears to be about 14.7:1 or an average. Just trying to figure out if my carbs could be dialed in better. Thanks.

Posted by: TimT Jul 28 2003, 06:47 PM

Those graphs look pretty good.

what rpm and gear were you doing the pulls from?

looks like things get rich around 4000rpm then hover around stoi from 400+

too rich at 4000 then safe at 5000+

you could use a touch smaller main jet, and a different emulsion tube.

This is a case were I wouldnt use a 125 instead of a 130 main jet, I would ream a 125 till i got the power that is available.

(dont know if your using 130's its just an example)

Posted by: drew365 Jul 28 2003, 07:14 PM

Thanks for the advice Tim; all the pulls were done in 3rd gear except the original test run was in 2nd. A weber guru set up the carbs so I could run the Virginia City Hillclimb last year and they haven't been changed since. I believe he set them pretty lean since the hillclimb is at 8,000ft. I'm not sure what size main's he put in but I seem to remember 150's being mentioned.

Posted by: TimT Jul 28 2003, 07:34 PM

Drew it not only the mains that make power the emulsion tube controls the transitoin from the idle circuit to the mains... I have a weber manual somewhere that outlines the applications for the differen emulsion tubes i.e. F3, F125 etc.

Ill look around for it

Most of the recipes for what we are doing have already been worked out....

Posted by: Racer Chris Jul 28 2003, 08:55 PM

If you have a cam with a lot of overlap, that would explain why it is rich in the mid-range.
I think it is way too lean in the upper range for sustained WOT. The cure would be smaller air correction jets. Full power mixture should be near 12.8 to 1 to prevent detonation.