D/A + CSL Header and Multi Exhaust System Test (Dyno Results
 

Below is a link to the dyno test results from extensive dyno test sessions I did in cooperation with Sean from Discovery Automotive, Peter Van Wingerden at HP Autowerks and Bob at Bimmer Performance Store.

This is the data that was used in the Roundel tuning article that was suppose to be in print some time back.

All the dyno runs were done over the course of a two to three months on the same dyno. The peak numbers are the average of the three best pulls. As some of you are already aware, there were some issues with certain mid pipe designs causing a resonance that would force the VANOS to adjust wildly and resulted in a sharp torque drop in the lower RPM ranges. Some of you have reported this as "hesitation" and PM'd me about the problem. My understanding is that later production versions of the midpipes resolved this issue.

We analyized the problem extensively, trying many combinations of exhausts and midpipe, both on the dyno and while driving onboard scan tool where we could watch the VANOS in real time. Peter, with the help of the guys at D/A and Gustav at GSP concluded that crossover location in the midpipe was the culprit. Moving the crossover location too far forward in the midpipe was detrimental to the low and mid range torque, even though it would otherwise produce a "hero" peak hp number on non-vanos cars.

For comfirmation, Peter hand built a "custom" midpipe using a high grade Burn Stainless x pipe cross over. (see pics.) The final result was that we were able to maintain peak power levels and resolve the low end torque drop/hesitation issues. We also tested a "mod/straight" pipe with no crossover in it at all, this did not yield the best results even though it did solve the torque drop/hesitation issue. Further confirming the effect of improperly placed crossover.

I have dozens of dyno sheets, with various layovers, rather than post them all I'll just keep and eye on the thread and see what you guys are most interested in.

The dyno sheet that I posted was our best reproduceable result which shows an honest 37rwhp gain using D/A Race 91 octane software, coated CSL header, custom midpipe with Burns Stainless crossover, AFE intake, and Borla exhaust.

(The UUC exhaust that was tested here, was a prototype that never went into production.)

The test car is 2002 manual M3 with D/A 91 octane "race program", CSL Jet Hot coated headers, AFE intake, and the various exhuast systems, the car only had BHS underdrive pulleys. All dyno pulls including the baselines were done at A&A Corvette in Oxnard CA, 200ft above sea level.

Here is a link to the spreadsheet summary...
http://www.brouwersusa.com/Exhaust%20Matrix.xls

that is goodd data and test method...

amazing the loss of low end torque with some combo's

For those of you data geeks... here is the summary of every run and configuration, including the baseline.

There are two worksheets in this file, one is a "Chart 1" visually summarizes all the data, and "Sheet 1" actually has all the data in it.

http://www.brouwersusa.com/Dyno_Data...preadsheet.xls

37whp is crazy... thats pretty impressive for just intake/headers/software/pullies/exhaust.

so where does that custom midpipe go? is it in section 1 or 2? im guess its in the section 1 place as you are not running cats? will we be able to get our hands on that custom midpipe ? thanks!

Very interesting as I have been thinking of putting my RDSport crossover section2 back on in favor of the SS X-pipe that's on the car now.

Were these tests performed without cats. 37hp without low end loss is fantastic. I think DA has similar packages using AP headers, will the AP headers yeild similar gains?

Are all the borla midpipes tested the v2 version (because only the last row mentions such).

Also, looking at those numbers is making me rethink my full borla catback plans (midpipe+muffler)

How does a freaking mid-pipe effect the cam timing?

hmmm this sounds good :thumbsup2:

midpipe goin into production ?