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need some help....


pontiacfreak142

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ok, well basically im having problems with the bird. Most cars (at the track anyway), usually vary maybe a tenth or two depending on weather and humidity, but my car is fucked up when it comes to that. like a couple weeks ago, it went from 85 degrees to about 75, and i went from running a 14.5 to a 14.2, and its getting rather annoying, especially since i bracket race.

 

the reason for posting this is, those of you that were at the track day last sunday, may have seen my car running low 14's all day (14.3 was my worst pass of the day with a 14.1 being the best). I know kil kare is a bit faster track than trails is, but i could get the car to do better than a 14.5 tonight, no matter what i did. im pretty sure it was a bit more humid out tonight than it was sunday, but id guess the temps were about the same.

 

The only thing i can come up with at this point that might be causing the problems is my air intake. I know only like 1 or people here have ever seen it so ill try to find pics. To give ya an idea though, i have an air filter fitted onto the throttle body, but 2 tubes running out to the front of the car where the fog lights used to be, like a ram air setup, excpet only the bottom half of the filter is coverd up, and the top half is just sucking what ever air is the the engine compartment. Anyone else think it might really be hurting me? any other ideas on things i might try?

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Some random ideas, amount of fuel in the tank, quality of fuel. Not really sure. How do your 60' times compare? MPH the same? Would be helpful if you could be watching your timing and air fuel ratio to see if it is changing at all. If it picks up a little bit of knock from god knows where, even if it's false knock, will slow you down. Going to the tuning software like you have talked about, and logging a few passes might shed some light on the situation. I really don't see your intake causing this, it was the same and has been that way for some time now.
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Some random ideas, amount of fuel in the tank, quality of fuel. Not really sure. How do your 60' times compare? MPH the same? Would be helpful if you could be watching your timing and air fuel ratio to see if it is changing at all. If it picks up a little bit of knock from god knows where, even if it's false knock, will slow you down. Going to the tuning software like you have talked about, and logging a few passes might shed some light on the situation. I really don't see your intake causing this, it was the same and has been that way for some time now.

 

 

well what do you mean compare? compare to what? times from sunday and last night?

 

buck, not much of one. i had it tuned by intense a while back but i later found out i was only running on 5 cylinders, and had stock length pushrods still in it which i was told might have been keeping the valves open to.

 

damn, thats alot of timing, im only running 25 degress

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buck, not much of one. i had it tuned by intense a while back but i later found out i was only running on 5 cylinders, and had stock length pushrods still in it which i was told might have been keeping the valves open to.

 

damn, thats alot of timing, im only running 25 degress

 

Maybe one weekend you could swing by and I could scan it to see what's going on.

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Yes, and being able to log data would let you know what has changed if anything.

 

 

i know it, im gonna get hptuners one of these days so i can.

 

as for times, my PB for sunday was 14.18 @ 94.35 mph with a 1.93 60, but had pretty consitant 14.2's at 94 mph with i think 1.95 60's all day even with hot lapping it quite a bit. the best i could get out of the car wednsday was a 14.44 at 92 mph with a 1.98 60, then nothing better than a 14.5 with 2.0 60's the rest of the night.

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60' times aren't slipping much at all. I'd think it's falling off down the track for some reason. Something isn't right, the tune is def a possibility. The mph dropping off like that could be the loss of timing, knock can cause that, but you have no way of knowing. Something dragging, like a brake caliper could be the culprit too. You'll just have to try to eliminate things. Carefull detailed inpection of the entire car would be a good starting place. If there is anything I can do to help let me know.
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60' times aren't slipping much at all. I'd think it's falling off down the track for some reason. Something isn't right, the tune is def a possibility. The mph dropping off like that could be the loss of timing, knock can cause that, but you have no way of knowing. Something dragging, like a brake caliper could be the culprit too. You'll just have to try to eliminate things. Carefull detailed inpection of the entire car would be a good starting place. If there is anything I can do to help let me know.

 

 

well i deffinately wouldnt count a bad tune out for some of the problems.

 

as for the mph dropping off, i honestly do think its that damn intake of mine. the car never used to change so much in different weather conditions as it does now. hell back when i just had bolt ons, i still had the stock intake on it basically except i took the air box out and just put in a cone air filter on instead. the car was pretty consistant no matter what. the biggest jump in time it ever had was when i took it out on a wednsday night and ran a 15.4 in mid 80 degree weather with decent humidity, then came home and took out the spare tire and jack and took it back to the track a couple days later when it was cooler and ran 15.2. it did it the last time you were at trails to. it was running 14.5's the entire time you were there, then after the sun went down i started running 14.2s, and that was with just a 10 degree drop...

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Something is making more sensative, I just don't see it being the air intake but stranger things have happened. Hell it could be a faulty intake temp sensor, what has been done to that?

Man I wish I had all the anwers. :rolleyes:

 

 

actually that thing is pretty much just rigged up and shoved into a little hole in the front of the air filter lol so it probably aint doin to much.

 

im just guessin it is the intake cause ive had quite a few people tell me it would probably cause problems since it is mounted right near the motor and the radior/fans, so its right where all the hot air is.

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I understand that the location of your air filter isn't the greatest. Here is a few peices of info most people don't realize. (I mean no offence) Ignition timing, in the past, was tuned by increasing it until your mph leveled off. So in turn if you lose timing for some reason your mph will drop off. We don't know for sure if this is happening, but the most common cause is knock, false or real. However the PCM uses the intake temp to pull timing due to heat, that is why some people extend their IAT further from the engine while others measure the resistance of the sensor cold and replace the sensor with a resistor. These would be things to look into. You could try replacing the IAT with a resistor, but that could cause knock also. You need to be able to monitor some of this info to be safe experimenting. I have an Interceptor gauge and wideband wired into my car to watch all of this in real time. I could be way off base, but the lack of info is what you are really battleing.
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I understand that the location of your air filter isn't the greatest. Here is a few peices of info most people don't realize. (I mean no offence) Ignition timing, in the past, was tuned by increasing it until your mph leveled off. So in turn if you lose timing for some reason your mph will drop off. We don't know for sure if this is happening, but the most common cause is knock, false or real. However the PCM uses the intake temp to pull timing due to heat, that is why some people extend their IAT further from the engine while others measure the resistance of the sensor cold and replace the sensor with a resistor. These would be things to look into. You could try replacing the IAT with a resistor, but that could cause knock also. You need to be able to monitor some of this info to be safe experimenting. I have an Interceptor gauge and wideband wired into my car to watch all of this in real time. I could be way off base, but the lack of info is what you are really battleing.

 

 

exactly, i have no clue whats going on. do you think it could cause that problem where its at? (you can see it in the second pic i have posted). The only thing that sucks though, at least until i get a new intake setup, i have no where else to mount that sensor that would be in the air flow.

 

hey buck, when you scan my car, will you be able to tell if its pulling timing and such?

 

and correct me if im wrong, but dont those IAT sensors have to have ait going past them to get an accurate reading? cause where its mounted, i cant really see that happening since its not really getting any flow going past it

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25 degrees of timing doesn't seem like much, I'd pull the connector off and install a resistor. Eliminate that as a possibility. It would take you a few times to the track to see a difference. Buck's software sould show everything you need to see. I am considering putting some attention to my wife's 3.8 Impala, and the DHP software is one of the first things I would consider, of course Buck has a lot more info on it. If you guys get to work on it I would love to observe.
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How many miles are on the motor? When is the last time you changed the oil? How much tread is left on your tires?

 

Hoping for an easy solution for you...

 

 

umm i think about 48 thousand on the motor, about 2 months ago, they are basically new slicks.

 

unfortunately, there are no easy solutions on this car LOL.

 

scott, ill let ya know when we figure out a day to do it. i hope he can check everything, id also like to see if it can check injector duty cause i have a feeling im leaning out real bad on the top end to.

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Scott if you ever wanted my input on tuning I'm not the greatest or best, but I can make small adjustments without blowing shit up.

 

Same with Gary. I can program pretty much any 3.8 w-body or RWD car out there. My tuner is wide open.

 

Gary. yeah, I can tell if you're pulling timing. The big thing would be if you're getting KR. Say you're getting 2-3 degrees of KR and your PCM is set to 25 degrees. Now you're only getting 22-23 degrees because of the KR. Several things can cause this. Heat, the tuning. Is it a stock PCM? Have you dyno'd your car with a/f?

 

I can check your Injector pulse widths. I doubt your maxing them out yet. L36 injectors are good to about 250 WHP. I dyno'd at 233 with my L36 NA and my IPW's were 24 lol. (static is what.. 21? ). car never ran out of fuel though and ran fine.

 

Let me get my car up and running tomorrow and we'll see what I can do next weekend.

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Scott if you ever wanted my input on tuning I'm not the greatest or best, but I can make small adjustments without blowing shit up.

 

Same with Gary. I can program pretty much any 3.8 w-body or RWD car out there. My tuner is wide open.

 

Gary. yeah, I can tell if you're pulling timing. The big thing would be if you're getting KR. Say you're getting 2-3 degrees of KR and your PCM is set to 25 degrees. Now you're only getting 22-23 degrees because of the KR. Several things can cause this. Heat, the tuning. Is it a stock PCM? Have you dyno'd your car with a/f?

 

I can check your Injector pulse widths. I doubt your maxing them out yet. L36 injectors are good to about 250 WHP. I dyno'd at 233 with my L36 NA and my IPW's were 24 lol. (static is what.. 21? ). car never ran out of fuel though and ran fine.

 

Let me get my car up and running tomorrow and we'll see what I can do next weekend.

 

 

nope, its not a stock pcm, i had to get a 97 cause the 96's were untuneable. Yes, the car was dynoed with a/f, i have the graph around some where.

im not quite sure what im making power wise. last time it was dynoed i made 222 hp and 225 tq, but also had bad valve guides (although not sure how bad they were at the time of the dyno, but still had a very nasty tick from the valves bouncing around a bit), and still had stock length pushrods, which i was later told were to long.

 

thats really weird, with yours, did you have like great bottom-mid range power, but crappy top end? cause im pretty sure thats what half my problem is with this car. im pretty sure its capable of pulling off 1.8 60's with a good tune, but im only trapping 95 mph at best.

 

im just really confused about this car, like i think something is wrong, but at the same time i just dont know. There was a guy on a v6 site im on running the same cam i have, stock heads/intakes, with a 3200 stall i think, 1 piece drive shaft, i think he had a few valve train upgrades, and good tires and 4:10 gears, and a good tune running 13.5's @ 100 mph. so basically he has better gearing than i do, his 4:10 to my 3.73, but i have ported heads. so im hoping that i just have a very shitty tune lol

 

sounds good, i work till 2 in the after noon saturdays and sunday's

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