hi guys i just got in to work and wanted to give an update on our built z. at 24 pounds of boost we produced 638 rwh corrected. however, we settled back in at 21-22 pounds. at that boost level it produced 616 rwh and 662wtq corrected.i was a little dissapointed in the results but i had a feeling we would be well outside the efficiency range, thus smaller gains. 18 pounds of boost seems to be where the turbos are "happy". we will be rebuilding,or upgrading, the turbos this winter. i will try to post pictures and build specs if anyone is interested.-thanks jason

 

if your A/F is steady at 11.5'ish, you might try playing with the timing....it will have a dramtic impact on your power. Good numbers though. According to the compressor maps, the Greddy reaches peak efficiency in the 20-25psi range...so you are right there in the sweet spot.

 

thanks gq, we did play with the timing and it made some improvement in hp but the tq seemed to benefit the most. i am sure there is probably more power to be had with additional timing adjustments but we ran out of time to tune. we may just wait until winter and work on the turbos. we will see what times and mph it can pull tonight at bandimere. thanks again jason

 

GQ,

Can you point me to those maps please?

 

At 24 psi, the higher torque reading but lower torque seems to point to dropping efficiency because max torque is usually around 5200 rpms and max power is close to redline. Can you please post the dyno chart?

 

Is that with 93 Octane?
Would you post your setup?
Thanks!

 

nice

 

enron exec, i will post dynos today or tomm. at the latest, we are still doing a few more things today before we head to the track. on our final run,not the highest, we produced 662 rwt at @4800 and 616rwh @4800 both corrected #s.once we post the dynos any input would be appreciated. power and tq slowly falls off from peak to redline. we adjusted timing,rpm offset in profec and our set. the only thing i can think of is at 21 plus pounds the turbos are struggling to maintain boost?? for comparison our baseline was at 18 pounds and we developed 572 rwh at redline and rwt of 579 at about 4500.-thanks jason

 

Bini2, that was with race gas however i do believe we could run this power level with pump would just have to watch timing very carefully.i will post setup in my sig.i believe that would be easier, but if you have any questions after seeing info just ask.thanks jason

 

https://my350z.com/forum/showthread....threadid=81141

 

Thanks...I was hoping he had an original though.

 

ice...i dont have the originals. I reply on the expertise of Squill and Gurgen when it comes to turbo effciency.

Blrd, was your boost falling off at higher RPM? If you are hitting peak power at 4500rpm or so....something is not right. It points to either a boost leak, or the stock ECU rapidly retarding timing to avoid detonation. But sounds like you ran race fuel..so not sure what to make of it. You might wanna hookup and OBDII scanner/logger and monitor your ECU timing in realtime...looking for abrupt drops in timing at around 4500rpm.

Also, if you are using a boost controller, it may be inconsistent at this super high boost level. Ideally, swap out the wastegate springs for the lowest boost setting you will run...lets say...20psi. Then use the boost controller to get you to 25psi or whatever your target is.

 

18 psi, 572.9 hp and 579.2 tq

 

21-22 psi, 616.0 hp and 662.0 tq

 

Any pics of the car/motor/etc?

 

Hrm, Looks like you need to open up the head a little more to keep you power from dropping off so soon. Those Greddy 18g turbos should be efficent up to 22 psi. 18 psi on a 16g is where it makes it's most power.

 

Head work..or timing. You have monstor torque.....i would check the timing first. Maybe we have reached the point where an upgraded cam shaft would help?? I cant recall if you swapped cams or did any headwork. Very interested though...keep us posted.

I will say your graph looks very similar to mine when I had too much timing retard. Monster trq numbers, but my HP peaked at 5500rpm and dropped off from there.

Can you verify that your boost was constant throughout the RPM band?

 

gq, we did hook up the obd11 their were no abrupt drops. timing is currently set a little behind stock. i would think this would be a fairly aggresive setting considering it started as na. we currently have 18 pound springs installed.what is strange to me is the difference in curves in the power and tq between the two boost levels. i am at a loss as to the lack of power at higher boost levels. i believe the turbos are at their max efficiency at around 19 pounds. i know this is contrary to the comp charts, but i am unsure of what else it could be at this point.any more ideas? i would hate to go through the trouble of turbos or a rebuild if it is unneeded. thanks for your help-jason

 

He has JWT Cams.

 

gq, i am a post behind you here. as you and etx suggested headwork may be the answer,however i have spoken with a few shops that have "flowed" heads and gains were negligible in comparison to the cost. they were not fi cars so maybe that would make a diff?