just PM Steph. I'm sure Corky would like the "challange"

Stephanie is reading this thread, if they are up for it and have a car to test I can send it out ASAP.

It's not a "challenge". Simply it is proof of concept. I'm personally not completely convinced the more complicated divoced wastegate type downpipe is better in a way that can be measure. I'm probably wrong, but would be cool to see a dyno, especially with spool data.

Jay

We have not dyno'd the car w/ the new d/p, but we will. I do have some comparision dynos on our website of the divorced wastegate downpipe vs. stock downpipe on an MSM though... It was good for 16 rwhp and ft-lbs torque. And an increase in torque in the lower rpm range.

As much as I would love to compare the downpipes, Corky would probably hurt me if I agreed to it. We just have too much to do and not enough time. I might be able to offer a discount to someone if they would like to do the testing themselves........ call or send a PM.
Stephanie

Jay, would you have any issue with sending your tony pipe to me for such a test?

Ben,

Send me a PM and we'll figure something out.

Jay

The comparison you refer to is between the stock MSM DP and the BEGI divorced setup right? I have no doubt that what you are building is better than what comes stock.

I question the difference between the traditional bell mouth (ala Tony) and the BEGI divorced setup, when comparing similar sizes.

Jay

+1, the question is whether it's worth spending the extra money over traditional 2.5" straight piping. i think we were are hoping the main pipe was going to be at leat 2.5" as well and not 2.25"

That's what I am thinking too. I'd love to see the differences between the two pipes, nothing else changed, same day, same conditions, etc.

On the one-off's that I do, it's a lot easier to do a bell-mouth than run another seperate pipe for the wastegate (I've actually never done a divorced wastegate setup yet). I want to see what hp could be gained for the big increase in fab time.

Steph, what's up.....:)
Mike

Car is running well. It gets dyno'd Monday. :)
Stephanie

Thanx Steph....:bigtu:
Mike:)

Does that mean that the car's emanage was tuned?

I think the divorced wg style is going to be better than a bellmouth 2.5in dp.

1. Less turbulence in the exhaust stream
2. You have less exhaust volume in the downpipe right after the turbine since the gasses are seperate from one another. So even though you lose the 2.5in you have less exhaust volume to move. Plus Its only 2.25" for a short duration and then it moves right back into 2.5".
3. The 15G's biggest problem is a small turbine, increasing downpipe size from 2.5" - 3" might get you 100rpm or spool and less than 5whp if anything. The biggest restriction is the turbine wheel, so worrying about which downpipe is better really is pointless in my mind.

I would expect both downpipes to act very similar, but it would be interesting to test theories by doing a back to back dyno. I think that there would be little to no difference between the two...the BEGI piece would have better boost control though, since it has a divorced wg pipe.

No tuning yet. When I drove the car the yesterday AFR's were okay. Nothing way to far out of range. But I was not doing fast accelerations either.

The downpipe will allow for faster turbo spool up due to the divorced tube.

BUT, we have discovered a good problem in 1 of a 100 downpipes. It has the capability to flow so well, that in certain circumstances the boost is not controllable. **We have only had this problem on 2 MSM's.** One I think was just a bad car from the factory (it had all sorts of other problems too). The other has been custom modified to dump the w/g vent tube past the CAT into the exhaust. Not an everyday problem. So far, no problems w/ Greddy.
Stephanie.

The greddy wastegate is notorious for being weak at holding high boost pressures to redline. Usually a helper spring cures the problem, i'm sure you'll see the same if boost is raised.

If you guys are really going to do a shootout, I'd also run the different DPs at different boost levels as there may either be a threshold point point where one is superior to the other. Just a thought as the difference may vary depending upon the boost level.

The emanage will not be tuned, until the car returns to Baytown, TX (Houston Area). Wideband has been installed. O2 clamp and Greddy Pressure Sensor will be installed once car is back in Baytown. Then rough tuning will start.

Don't you mean the opposite? On the Greddy's I've driven, the boost always tapers toward redline.

Off-topic
 

Thats sweet. I've always wanted an exhaust like that. Clean while cruising, dirty and fast while in boost. :naughty: