Good Day Gents
I went to the dyno a couple days ago. Built S50 9.0 CR GT35R on a 666 manifold 63 back housing with a M50 cams (long story on that on) 3inch cold side and 2 1/4 hot side for the intercooler MS3 as the managment. 15psi on 90 octane pump gas. What is causing the the top end to fall off so badly?
Thanks in advaince
I’m going to take a wag. Upload a picture where we can read the afr and I can do better.
1. Tuning
2. Back-pressure
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1989 535i - sold
1999 M3 Tiag/Dove - sold
1998 M3 Turbo Arctic/black - current
2004 Built motor TiAg/Black - Sold
2008 E61 19T Turbo-Wagon - current
2011 E82 135i - S85 Swap - current
1998 M3 Cosmos S54 swapped Sedan - current
1998 Turbo: PTE6870 | 1.15 ar | Hp Cover, Custom Divided T4 bottom-mount, 3.5" SS exhaust, Dual Turbosmart Compgates, Turbosmart Raceport BOV, 3.5" Treadstone Intercooler, 3.5" Vibrant resonator and muffler, Arp 2k Headstuds | Arp 2k Main studs | 87mm Je pistons | Eagle rods | 9.2:1 static compression, Ces 87mm cutring, Custom solid rear subframe bushings, Akg 85d diff bushings, 4 clutch 3.15 diff, , Poly engine mounts, UUC trans mounts W/ enforcers, 22RPD OBD2 Stock ECU id1700 E85 tune, 22RPD Big power Transmission swap w/ GS6-53
AFR is 11.7 not more at wide open throttle.
Could it be the vanos mapping? We did it 15 degrees across the from 3500rpm and off at 5000rpm
What size turbo housings ?? What cams ?? Aren’t you on standalone. Do you have the log ?
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Im no expert but that hotside sounds small and those cams sound slow.
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Everything in here
Or the vanos is staying active
- - - Updated - - -
Wait, i just read the comments in here
The VVT settings should be set to ON/OFF. Meaning you wont be specify a certain number of degrees, but rather when the vanos solenoid should be on or off
Generally speaking, your gonna want the vanos active at like 1200rpm and off around 4k.
You can easily find this out by making back to back dyno runs with the vanos on all the time and then another pull with it off the entire time. See where the 2 graphs would cross if you layed them on top each other
328i Sedan Twin s366's, 6.0LS, TH400, MS3 Ultimate
9.20 at 150 on 22psi
That .63 housing is waaay to small get somthing atleast i. The .9x range and watch what happens.
The differance in spool will be a few 100 rpm.
World record holder for a m52 stock bottom end.
9.41@153 c4 auto 28" et streets, e34 3.64 gearset 900+hp
E36 chassis irs world record holder 8.49@162
Th400, e85, 7685, m50 intake 26.6 lbs of boost
Thanks guys for the input really appreciate it.
@Dburt we actually did all Zero's in the vvt table for a few runs the car lost over 50 whp and TQ and then did a few run with the vanos activated from 3500rpm and off at 5500 rpm @10 degrees all the way up 20 degrees, no real change happened at the 20 degree so we left it at 15 degrees. the car lost power at the 5500rpm so we decided deactivated the vanos at 5000 rpm the car gained a bit of power in that area. when we go back to the dyno we will try the earlier activation of the vanos.
@ DasBoot I am in the process of looking for the bigger housings
Its the cams causing the drop in power up top. Not the small back housing. Sure a bigger back housing will flow a bit more, but those shit cams are killing your top end.
Your VVT settings should be ON/Off, not PWM. The vanos solenoid in the older 24v stuff is not meant to PWM.
Meaning, you shouldn't be targeting an angle in your tune. You should be targeting at what RPM and load the Vanos should be on or off.
But either way, ur cams suck.
328i Sedan Twin s366's, 6.0LS, TH400, MS3 Ultimate
9.20 at 150 on 22psi
@Dburt noted I will be revisiting the targets as was suggested for the vanos angles as soon as I can get back on the dyno, also noted on the sucky cams lol, I am thinking of getting the schrick camshafts 264/256 would that be a better choice?
As for Timing what's a medium timing figures compared to a high timing figures?.
Last edited by fastboy; 06-29-2018 at 11:39 AM.
pretty interesting i thought twin cams rev out WAY more that's like an m30 powerband.
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