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tuning 355 vortec stealth ram... stumped

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Old 03-23-2009, 09:54 PM
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Car: 1989 IROC-Z
Engine: 346 LS6
Transmission: T56
Axle/Gears: Hybrid 8.8 3.73
tuning 355 vortec stealth ram... stumped

well. i have to say ive been struggling with this car for a long time.
heres what ive got
355 flat tops
vortec heads
268xfi cam 1.5 rockers
24 pound injectors
kirban AFPR
HSR 58mm lingenfelter TB
4inch CAI stock maf
longtube 1 5/8 headman headers dual 2/5" y pipe 3"midpipe no cat hooker aerochamber
2400 vigilante converter
2.77 gears

Tune wise im a 89 Maf so im 165 6E ARAP base
mechanically the car is good. fuel pressure is 45psi, base timing matched to chip 6 degrees. max timing advance set to 31 degrees.. no problems.. however i have a knock count of 13 at lower rpms
TPS is set to between .57 and .59 at idle and is 4.63 at WOT
injector constant set to 24
egr deleted
fan times set for my 180 stat

ive been playing with idle between 850 rpm and 700 rpm... not sure were its more happy yet

Below below 150 lv8 im around 118 to 126 blm and after 150 to 250 im 128 blm

everything else is stock for now.. im not sure what to change to account for the throttlebody and extra plenum volume from the stealth ram... a few pointers would be greatly apreciated.

Lee
Old 03-23-2009, 10:27 PM
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Re: tuning 355 vortec stealth ram... stumped

Im not sure about the maf tuning do to using speed density myself but it would seem that your tune is pretty good?? One thing I did notice was that you are using 1.5 rockers. I do believe that the XFI series of cams is rated for the 1.6 rockers?? You are using the Roller cam version right. If not then ignore this comment. If not then you could be losing some power and lift do to the 1.5 rockers etc. Sounds like a very nice setup though. WHat do you think of the Stealth ram?? and how does it idle? Should be very fun with some steeper gears though!!
Old 03-24-2009, 01:17 AM
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Car: GTA -89
Engine: Blown 415"
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Axle/Gears: Strange 12-bolt
Re: tuning 355 vortec stealth ram... stumped

Not sure what your SA table looks like but you could always fine adjust the MAF tables some to get the BLM closer to 128 if you like.

* Try increase AE some, HSR usually likes more AE.
* Buy a WBO2 and tune fuel @ WOT

/N.
Old 03-24-2009, 04:41 AM
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Car: 1987 Monte Carlo SS
Engine: HSR 383 AFR180/268XFI EBL
Transmission: 200-4R, Edge 2800 L/U
Axle/Gears: 7.5/3.73/PowerTrax No-Slip
Re: tuning 355 vortec stealth ram... stumped

My guess would also be that you need some "pump shot" (AE). I think I'm in the same boat with my motor (383, XFI268, AFR 180s, modded SLP/Eddy intake). I've got the BLMs looking decent at cruise but need to get my idle a little richer. I'm getting knock on tip-in; so AE adjustments are next. Once I feel comfortable enough to get the car far enough away from the house, I'm going to get my O2 bung welded on for the WideBand install.
Old 03-24-2009, 06:58 AM
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Car: 1989 IROC-Z
Engine: 346 LS6
Transmission: T56
Axle/Gears: Hybrid 8.8 3.73
Re: tuning 355 vortec stealth ram... stumped

i added a little bit of AE on the bottom end and it seemed to help..

As far as the 1.5s go... i had the 1.6 rockers but the stock vortecs can only take so much lift until the fastburn effect stops working. i was running 575, 565 lift with the 1.6s but i feel that with the 1.5 [535, 530 lift or something like that] that the engine is a little crisper.

As far as widebands go.. i bought the dual LM2 wideband kit but im still learning how to work it. The only trouble im having is figureing out how i am going to log with rpms... i dont have an MSD box and the LM2 you cant hook up to a spark plug... im a little stumped there.

The stealth ram seems to idle just fine.. but i havent been in all weather conditions yet. however i notice a big low end loss of torque compared to my siamesed SLPs
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