Problems-- car not running right.. atleast it is not trapping as high as it should, if you look at my sig it list just about every mod on the car. i had it dyno tuned before the 58mm tb and suspension work, and it put down 408/437 rwhp/rwtq. and i cannot seem to get the car to trap higher than 111, what are your take on this situation, it seems like its running fine but when i go down the track, at about 4500 rpm the stock tach will jump and flutter from 4.5k rpm- about 7k rpm, i have a shift light and aftermarket tach and they stay steady on the mark and do not flutter or jump. but when this happens the check engine light will come on, then go off, seems like its running alright, is this knock? spark issue i need sugestions, have no idea where to start w/ this, i cannot get my lap top and pcmia card to work w/ tuner cat.

please help me!

thanks,
Bobby

 

When you say "1.6RRs, etc." I assume that you have springs to match the cam. otherwise you may be experiencing float at higher RPMs.

Other than that, I'd get a read out on A/F. JMHO

 

yes the valvetrain is k800 springs ti retainers keepers, w/ comp chromoly pushrods. The car was dyno tuned, if you give me some time i can get the chart and a/f readout uploaded, it is wierd- the tuners told me my car stops makin power at 5800 rpm, which is completley contradicting to the gm 847 cam specs and etc.. anything else you could suggest im just really at a loss here theres lots of money in this car and i just want it to run right, and not have to worry about little things.

 

You might have some ignition problems. The trap speed is way low. If the car feels good to you take it to a different dyno and see what it does.

 

I talked with Lloyd about the fact my car quit pulling at 6000 RPMs and he stated it is probably the heads and intake. Who did your head and intake porting? From talking with him, the way I understand it is if the heads cross section is not changed or if the intake is not ported correct the bigger motors wont make power much above 6K no matter what cam is in them. You have decent dyno numbers but Dyno numbers are subjective and track data is the only true way to see where you are at.

 

the car feels very strong, really powerful low end side def, it'll yank the tires off launch and dance them w/ the 1-2 shift, but i dunno what happends. rooster if i were to get the old log or tune sheet from them, would u mind taking a look at it? also i have a few ?'s for you, my car wont work w/ the akm supplied cable, my toshiba laptop and the pcmia serial port adapter- when i connect to my pcm it'll say unable to read pcm. im sure the adapter and laptop work b/c it works w/ my buddys cable and tunning software for his 05 wrx. any suggestions..


also what kind of ignition problems would u think? the car runs clean it seems.

 

Does the motor feel smooth up there or can you feel the crap out that is going on?

I'd log some data and see what your sensors are saying, then go from there.

 

the motor feels smooth, no breaking up or anything like that, it runs really really rich i do know that, you can smell it, especially at idle, eye burning rich, my fuel press. is at 35 key up and 39-40 wot.

 

I feel it's an ignition issue at higher revs. My 396 last year made almost identical power to yours (411/430) and it trapped consistent 114-115's.

 

Your heads & intake are probably to small for a 396 and it's running out of wind above 5500. Doesn't sound like there's anything else wrong.
Ya could go with a larger cam and help it(small heads big cam) but with stock castings ya gonna have to spend a LOT of money on them to get them to preform on a 396.

 

Have you ever scanned it to see why the light came on? Even if the light goes out, the code is stored and can be retrieved. You don't get an SES light for "knock". You get knock retard, not a light.

 

ok i see what you're saying about the heads/intake but i would def think that 415 rwhp would be enough to pull a 3400lb car through the traps higher than 111 mph, i dont doubt that the heads and intake are not letting me make power higher in the rpm band, what would be my best bet to make closer to 450-475 rwhp i would love to dip into the tens on hp, or definitley low 11's. i would think that afr's rather 210's 220's or something and maybe a custom grind? gearwise in the rearend i have a 4.30 and im running a 26" tire, dont you think there also is room for improvment w/ a 28" tire, actually how would the effect of the 28" vs. the 26" tire be on the 60' mark, i spin a little outa the hole now, but consistantly 60' between 1.75-1.64(best).

 

as far as scanning it, no i have not scanned it. i'm going to try to borrow the tech 2 from my work.

[ "it seems like its running fine but when i go down the track, at about 4500 rpm the stock tach will jump and flutter from 4.5k rpm- about 7k rpm,"]


^ has anyone seen anything like this before? opti, coil maybe pcm??

 

Could be a bad ground, or weak charging system voltage. How does the dash volt meter respond when the tach is acting up? Does the speedo also do a little dance?

 

thats true, i'll look into that- the only thing that comes to mind is that i recently moved the battery to the trunk and re-ran the ground and power cable from the trunk to starter then up to that red terminal, injuneer you wouldnt happen to have a diagram of power/ground w/ a battery in the trunk? maybe im not sending enough power to the car? or ground..