TracyRR

iTrader: (8)

Hello turbo guys... I dynoed this weekend and my numbers were less than impressive. I do not have a dyno sheet to show you but lets see if someone can still put me on the right track. Here is the combo: Rear mounted twin gt35r's t3 exhaust housing w/.63, stock sts piping, forged 370, 8.8 comp, fresh patriot stage 3 heads, 218/230 567/575 lift cut on 116 and installed at 116 i/c, a4 with 2800 vig conv, 3.42's... It made 620 rwhp at 110 mph which works out to approx 5250 or so rpms. We pulled it up to 6500 rpms and the power steadily declined after 5250 rpms.... The power dropped down to 460's at 6500 rpms.... 12 Pounds of boost. AFR's at 11.5's and the total timing was 18 degree at full boost. It runs great, it just doesn't make any power. Thanks for any help guys! Let me know if you need more info.

TracyRR

iTrader: (8)

My goal was 800 rwhp at around 6500 rpms.... Someone said to turn up the boost but i didn't only because i did not expect the power to decrease so much after 5300 rpms on 12 pounds of boost.

30th t/a

iTrader: (51)

does it hold the 12psi all the way to 6500? or does the boost drop off?

NicD

iTrader: (7)

This, is it steady or does it drop?

Also what kind of valve springs do you have? Maybe also switch back to stock rockers since the yella terras might be causing some valve float due to marginal springs, high exhaust backpressures, etc.

TracyRR

iTrader: (8)

hey 30th/nic, yes, it holds it smooth all the way up... both wastegates are screaming and the boost is steady. The patriots were just freshened by patriot and they said the springs were good although i did not check the rates. I have had valve float before with a different car and it would not rpm well at all but this thing revs fine up top but no power. We thought about backpressure but STRY (on corvette forum) has the same turbo's but a larger motor and had the exact same exhaust housings and made over 1000rwhp on the same rear mount. He was running more boost and had a larger motor so this may point to me upping the boost levels. Thanks for the replys.

NicD

iTrader: (7)

Get the dyno graph posted up. Maybe it was blowing out the spark up top? Cam sounds pretty small for a 370, maybe it's just not going to pull that high.

TracyRR

iTrader: (8)

the tuners printer took a dump so no sheets right now.... The cam is small but i sure thought it would peak higher under boost. thanks t

82swbLQ9

i did a little math on my set up with the 35r's and its gonna take 17.5 psi to make 800 flywheel hp. that would mean the motor is moving about 44lb/min of air per turbo. i wonder if backpressure is not letting it breathe past 6000rpms? you can always check with a backpressure gauge. the turbines are a little small. at least mine are with 3in outlets and about 2.25 to 2.5 inlets

TracyRR

iTrader: (8)

yes, mine are also 3" outlets. Where would i buy a backpressure gauge?

82swbLQ9

i bought mine from napa. it screws into the o2 sensor bung

82swbLQ9

also... did the power curve just peak and flatline? if so it could be an intake restriction. i had a 03 rustang that after 5300 would flatline on the dyno cuz it couldnt flow enough air thru the intake manifold

TracyRR

iTrader: (8)

The power declined steadily. It ended up at 460's around 6500 rpms. I have the ls6 intake so i'm supposed to be good there. I didn't check my air filters to see if they were collapsed or not but i'll do so today. t

TracyRR

iTrader: (8)

30th/Nic, i just spoke to Geoff (tuner) and he just mentioned that my boost did decrease 1 - 2 pounds by the end of the run..... Any idea what that means? thanks

MY99TAWS6

iTrader: (3)

Boost leaks?
GT35s should be able to do like 1400 engine hp .
What about trans and converter..Is this a triple disc converter..? Are you locking it on the dyno? single disc pretty sure would simply fry. What trans..Maybe trans is not holding the power.
What about knock retard..did you see huge knock retard?
What about fuel up top.What are you running for injectors, pumps..?
I can't see that cam being much of limiting factor. And with FI the heads and intake don't matter hugely either just mostly give you more power at lower boost.

TracyRR

iTrader: (8)

The trans is a new rpm level 6 with a triple disk vig conv, i did not lock it up though. The tranny temps stayed around 150 so i would assume it did not slip. It knocked a very small amount a couple of runs, most of the runs were clean. My meth pump took a crap so i have a new one on the way. I am running 80 seimens injectors, twin in take racetronix pumps, hot wires and twin -6 pressure lines with a -6 return. I will double check all my t-bolt clamps and connections for leaks. Thanks for the input! t

82swbLQ9

the boost increase could be wastegate creep

TracyRR

iTrader: (8)

it was actually boost decrease... the boost spikes pretty hard so it may be on the way down or i may have a leak somewhere... I'll check that part out very soon. thanks t

Slowhawk

iTrader: (12)

The Compression is too low for 12lbs and a rearmount.For that compression it should be set to atleast 14lbs but I would run 16lbs on the street -pump gas.If the plan was 12lbs with this kit I would of recommended atleast 9.5-1 compression.

Up the boost a few lbs. I bet the power will jump nicely.

black98ws6ta

iTrader: (77)

I bet it is falling off up top due to backpressure.

TracyRR

iTrader: (8)

Yes, i only stopped at 12 because i was worried about the power peaking so early and dropping off so soon. Once i get my new meth pump (other one crapped out), i'll increase the boost if everything looks good. Do i have to get a three bar map if i go over 15 pounds? If so, is it a big deal to convert from a two bar to a three bar map? Thanks for the help guys!