Went to MAC today

[JustDSM]

I pulled right up on the rollers not 5 min from pulling off the freeway (from doing 85-90 for 1.5hrs) made 3 passes in 8 minutes. The final pass was my "best". Here are the sheets:





While everyone around said the numbers were "good" I think there's more in the car. I have not retuned the car for the new compressor inlet pipe or the new shorter/smoother upper intercooler piping. The compressor inlet is known to screw with the tune a bit.. I'm just curious how much I'm leaving on the table.

Mods that matter:
Reflashed ECU (Dynoflash) tuned for the mods in bold
Buschur 3" Turboback
Buschur Air Filter
MBC @ 20lbs
91 Octane
Walbro 255lph HP Fuel pump
Buschur Compressor Inlet Pipe
Buschur Upper Intercooler Pipe
"Mini Battery"

Finally, what do you guys think?

[KeltonDSMer]

That is simply amazing to me that the turbo can flow so much air at this altitude. As far as more room left, I'm not sure.

These dyno graphs are beautiful curves. From 5-7.5K there is over 300WHP, wow. Now I know what David means by his graphs not "dropping off" :)

There is an example of a situation where taking the revs to red-line is actually usefull.

I was looking at the dyno charts for the SCC EVO project car and their Vishnu parts obviously can't cut it. The power curve starts falling by 6K RPM, which makes me wonder if the special "peak HP" number really means anything at all.

[KeltonDSMer]

Oh, is the red graph corrected numbers? Even so, very impressive.

[jmakado]

looks good....it's pretty impressive that a "generic" reflash can get so close to 11.5 AFR. if you had some way to manipulate the AFR i would take a little fuel out from 6600rpm-6900rpm and maybe you could get rid of that little dip.

[jmakado]

Originally posted by KeltonDSMer
That is simply amazing to me that the turbo can flow so much air at this altitude


i agree....i think that big turbine housing (9.8cm^2 i think) has a lot to do with it performing well at altitude.

[v413nc3]

Good looking flow :) I agree you should be able to see some more out of it. From the looks of it all I would say that you need to decrease backpressure or increase front pressure at higher RPM's. Both should be accomplished with larger cams.

[dougs90gsx]

Turn up the boooost! :p looks good!! Still a little more to go!

[KeltonDSMer]

I think backpressure is underrated for how important it is to performance in the general DSM community. A member of Bushcur's forums did a test on his modified 2G GST and he found there was almost 9psi of backpressure before the cat:eek: I'm not positive, but I remember reading that 2-3psi is optimal in a turbo application. How does altitude affect backpressure? Can someone elaborate on this furthur?

[Mirage]

Actually, no backpressure post turbo is optimal on a turbo car. For all of these "torque" issues created without the backpressure, the turbine housing creates enough backpressure for the engine.

Post turbo is where you want it to breathe. having more backpressure also will increase the spool time and the overall amount of boost that you can run (ask me how I know... :D )

All IMO of course with experience.

Marcus Martinez

[JustDSM]

Originally posted by Mirage
Actually, no backpressure post turbo is optimal on a turbo car. For all of these "torque" issues created without the backpressure, the turbine housing creates enough backpressure for the engine.

Post turbo is where you want it to breathe. having more backpressure also will increase the spool time and the overall amount of boost that you can run (ask me how I know... :D )

All IMO of course with experience.

Marcus Martinez

Agreed.