Help!! Stang is slow after upgrades...long

[VelR5.0]

Hey guys I took my car to the track last night and it pissed me off. My best time so far is 13.28@106 with a 2.05 60ft at Fayetteville,NC. Well last night I ran at Darlington,SC and the best time was 13.58@101.74 with 1.92 60ft. First thing; when I ran my best time in Fayetteville I was running with normal radial tires,spare tire, jack, 19lb injectors and 70mm MAF. Last night I was running with BFG DR's, 24lb injectors,73mm MAF and spare tire and jack removed, so you get the picture now! The tunning at Fayetteville was as follows; 16* timing, 45psi fp, disconnected sway bar. Last night I started with 18* timing, 38psi fp, diconnected sway bar and DR's at 15psi. So what I am missing here? The car lost almost 4mph!! After the first pass last night which was the best btw I decide to go back to 16* timing since my trap speed was down. To my surprise the car ran a slower et, bad 60ft but the same mph(101). At this point I decide the engine maybe is lean at the top end so I went to 40psi fp and the car responded with a slightly better et at 102mph. Again I thought it likes more fp so I went to 42psi and again the car responded with a very similar et at the same mph(102)!! One more pass lowering the FP back to the original(38psi) and still went high 13's@102. Ok guys this story is too long but this is driving me crazy!!! There's a dude offering me 5k for my car and I'm about to do it, because it seems that I wasted my money on better upgrades. Could you please give me some advice before I sell my baby??? Sorry guys to make you read this, if you did it thought!! Hehe Thanks in advance!!

Velez

[FordFreak300]

One difference may be that it was two diffrent tracks and the temperatures were not the same, what are the elevations? Heree in California a lot of peopel used to run at a track called Carlsbad, it was right about sea level, but an hour and half away is another track were I run normally which is 2,000ft above the other track. That's a huge differrence. It's a differance of roughly half a second. if you were running in hotter temps then that is another huge issue. Also humidity plays into it. I believe you get a lot of humidity in SC right? Tell us the differences in temps and humidity and the elevations. I'm thinking that is your issues right there.

[VelR5.0]

FordFreak300 I believe you could be right about temps and elevation. I wish I knew these information, but neither tracks will give you this info on the time slip. Yes there's a lot of humidity here in SC. Both tracks are located pretty much center south of each state you can draw an imaginary line, as a matter of fact they're close to I-95 that runs from NY to FL. Thanks for the will to help me!!

Velez

[nav_sc]

Elevation ask in some local forums or look it up,Temperature and Humidity,
Have you check the compression of the motor? bent valve? missed any gear?
car is making any strange noise or feeling differently?

Do a tuneup, gasoline filter and sparkplug get back fayetteville that is my only recomendation

[VelR5.0]

Originally Posted by nav_sc

Elevation ask in some local forums or look it up,Temperature and Humidity,
Have you check the compression of the motor? bent valve? missed any gear?
car is making any strange noise or feeling differently?

Do a tuneup, gasoline filter and sparkplug get back fayetteville that is my only recomendation

I was revving the car today, directly from the throttle and it sounds like the rockers are loose or some of the pushrods might be bent. Sounds like a bicycle bell metal sound when the engine decelerates. About the tune up I think it's time for a new fuel filter. So I'm going to be buying around for a new plenum intake gasket and the filter. Thanks!

Velez

[rsw007]

somethings off, you might just need a dyno tune to get the timming and fuel right.

[FordFreak300]

I'm nto saying any of the other suggestions are wrong. I agree with them actually. But to give a referance. In my currently slow car(whch is slowly getting work done it so don't laugh at my E.Ts) I ran last January at about 60*low humidity. I ran a 15.3 @ 91 Mph... Then I did some stuff to the car in the mean time. I went back out in august and ran my car again, in 100+* weather. My track lock was going out on my car though, I had a vacume line disconnected I hadn't noticed plus a few other little odds and ends. I ran a 15.3@92mph. So in a nutshell just looking at the times, it seems like I did all this work to my car over 8 months and only gained 1 mph and no E.T. when in reality I overcame the odds of a failing track loc, and leavign teh lien with one tire spinning, the disonnected vacume line, and a few other things. Like I forgot to readjust my lifters after I let them pump up when I installed them so they were out of adjustment. Not to mention there was over 40* different in air temp and a huge differrence in humidity. Obviously I gained soem HP along the way. Ahh yes I forgot to mention I also had rao racing springs in my car for the aug run so I had no weight transfer. Usually tracks have a web site, you can look up the elevation there. If you are tryign to better yoru times, then always run the same track and note the temp. Most tracks will anounce the temp from time to time. I'm hoping to drop my car into the 13's here with in the few weeks. I have made many more changes.

[VelR5.0]

I agree with you that weather plays an important part on the ET's. I'm going to try to find out the elevatio of both tracks. Later...

Velez

[s151doc]

id say its the weather.i've run at my local track in the dead heat of summer with alot of humidity and only run around 104 mph but run at the same track in the fall with lower temps and humidity and run 107mph.later

[VelR5.0]

I changed the fuel filter and had a talk with a friend who has knowledge about stangs and he said to return my timing back to 16. I did it and also lowered the fp to 36. I kept looking around the engine to see if I could find something wrong with it. I checked the TPS voltage since the idle was a little rough and to my surprise it was at .968 and the last time I set it was at .941. So I put it back to .941 and the idle is smooth like is was before and for some reason(imaginary maybe) the car feels strong again the way it felt before. I know it can be the timing,fuel filter or lowering the fp to 36 but I like how it feels now.

Velez

[FordFreak300]

glad yu are gettign things worked out.

[VelR5.0]

Thanks for the help man!!

Velez

[FordFreak300]

well I didn't really do much but sit here on the computer and give you a few ideas. Turns out it wasn't anything any of us suggested. But atleast now you knwo to check elevation and temps, and the two added together bring about a hole way to measure it called DA. Most of the time the track I am running at which is about 2,500 above sea level has a DA of around 5,000 feet above seal level in teh summer heat. So it is like I am runnning at 5,000 feet not 2,500 feet like it is durring the cooler months. I race with a few peopel who actually have little machines that measure this. crazy huh. Amazing how 40 degree's in temp and a little humidity can change everything huh.