96 t/a cammed on spray! horrible times.
09-08-2009, 02:40 PM
#24
HE is Short shifting the **** out of it. Hes prob never even hitting peak HP wich should be around 64-6500 and should be shifting 6800+ with that cam (wich is bigger than mine and I shift at 6800.
2.1 sucks but isnt the worst ive seen and he should still be running way better with that 60ft then he did. Im sure hes short shifting it.
2.1 sucks but isnt the worst ive seen and he should still be running way better with that 60ft then he did. Im sure hes short shifting it.
09-08-2009, 03:22 PM
#26
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lol i can drive pritty good i know my 60 needs work. other people have drivin the car and get the same time. the car cas a tune (base file) from speed inc, not a full tune. stock heads, i didnt knnow i could rev the car to 6800, i will try that but i am willing to bet 700 more rpm is not the problem here. i have torqe arm-control arms-panhard bar-shocks. i only gained 3mph in the trap with 100 shot wet and tr7's.
09-08-2009, 04:00 PM
#28
700 rpm is the difference between fast and slow since your not even making peak HP shifting at 6200. Its like shifting a stock car at 5300 instead of 6000 Huge difference.
Plus that cam is just to big for stock heads.
Speedinc tuned my car also I have a 230/236 cam and trap 120 NA shifting at 6800.
Plus that cam is just to big for stock heads.
Speedinc tuned my car also I have a 230/236 cam and trap 120 NA shifting at 6800.
09-08-2009, 07:46 PM
#31
A lot of bad information in this thread!
First, the cam is too big for stock heads but not that bad. 847 numbers are 236/242, .575/.595 (on 1.6 ratio), 112 LSA. My car did just fine with that cam. It's not optimal but it doesn't mean it's slow...
Second, with stock heads the best RPM to shift at is about 6300-6400rpm, tops. Peak power even with a big cam comes on around 5800-5900rpm because the heads choke it off before it can really reach it's "true" peak. Therefore he's not affecting his times too much shifting at 6100. He could gain something but not the 12-13mph he is down by...
Third, the 60' time is not the culprit at all!!! Even if he got it down and shave 2 or 3 tenths off his e/t, his trap would still be abysmal.
If the tune is a "baseline" or mail order type of tune (in other words, a "best guess" by the tuner based on what mods the car has, and based on NO data logging whatsoever) then it could be set with retarded timing and rich fueling, but it would have to be really off base to make it run that slow.
I would try and get it running what it should n/a before you continue throwing a 100shot on it. Get it dyno tuned, or if you can't afford that right now, just get a mail order from Madtuner.com or pcm4less.com, they should be able to get it a LOT closer to what it should be.
There is something WRONG here, either in the tune or in fuel/ignition system somewhere.
First, the cam is too big for stock heads but not that bad. 847 numbers are 236/242, .575/.595 (on 1.6 ratio), 112 LSA. My car did just fine with that cam. It's not optimal but it doesn't mean it's slow...
Second, with stock heads the best RPM to shift at is about 6300-6400rpm, tops. Peak power even with a big cam comes on around 5800-5900rpm because the heads choke it off before it can really reach it's "true" peak. Therefore he's not affecting his times too much shifting at 6100. He could gain something but not the 12-13mph he is down by...
Third, the 60' time is not the culprit at all!!! Even if he got it down and shave 2 or 3 tenths off his e/t, his trap would still be abysmal.
If the tune is a "baseline" or mail order type of tune (in other words, a "best guess" by the tuner based on what mods the car has, and based on NO data logging whatsoever) then it could be set with retarded timing and rich fueling, but it would have to be really off base to make it run that slow.
I would try and get it running what it should n/a before you continue throwing a 100shot on it. Get it dyno tuned, or if you can't afford that right now, just get a mail order from Madtuner.com or pcm4less.com, they should be able to get it a LOT closer to what it should be.
There is something WRONG here, either in the tune or in fuel/ignition system somewhere.
09-08-2009, 08:06 PM
#32
I had to shift my hot cam at 6100 he is short shifting it since the cam will pull beyond the stock heads will flow. It has already been said its not the best cam for his ap. Also has been told to dyno tune it. I didnt see any miss information. Although I do agree something else is off.
09-08-2009, 08:15 PM
#33
I had to shift my hot cam at 6100 he is short shifting it since the cam will pull beyond the stock heads will flow. It has already been said its not the best cam for his ap. Also has been told to dyno tune it. I didnt see any miss information. Although I do agree something else is off.
Like I said he is short shifting it a little but it's not enough to make a big difference in his e/t like you're thinking. Maybe a tenth or two that's it.
09-08-2009, 08:38 PM
#34
I think thats because his heads will not flow what the cam is designed to do. There for he is way short shifting the cam. He would be better off with a hot cam on spray than what hes using. Cam should be selceted on the motor surrounding it.
Not sayin your wrong but that cam is designed to pull 6400-6500 peak HP his engine cant keep up.
Not sayin your wrong but that cam is designed to pull 6400-6500 peak HP his engine cant keep up.
09-08-2009, 09:37 PM
#35
You're right that it's not the best cam for his setup, but it's still capable of performing much much better than what he is doing right now.
I'll just reiterate one more time... throwing a big cam that's designed to peak at 6400rpm in a stock shortblock does not mean that it will peak at 6400. The stock heads will choke it off before it can reach its "designed" peak. On the AI 200cc heads for example his cam might peak at 6500 and he would have to shift at 6800 or 6900 but on stock heads it will get lowered down to ~5900 like I was saying. In that case the optimal shift point would be 6300 or so. So shifting at 6100, only 200 lower then what the ideal probably is, is not affecting his times that much.
btw, just to put this all in perspective, a full weight stock shortblock + cam/bolt ons LT1 with a 100shot should be doing at least low 12's @ 118-120mph...
I'll just reiterate one more time... throwing a big cam that's designed to peak at 6400rpm in a stock shortblock does not mean that it will peak at 6400. The stock heads will choke it off before it can reach its "designed" peak. On the AI 200cc heads for example his cam might peak at 6500 and he would have to shift at 6800 or 6900 but on stock heads it will get lowered down to ~5900 like I was saying. In that case the optimal shift point would be 6300 or so. So shifting at 6100, only 200 lower then what the ideal probably is, is not affecting his times that much.
btw, just to put this all in perspective, a full weight stock shortblock + cam/bolt ons LT1 with a 100shot should be doing at least low 12's @ 118-120mph...
Last edited by Purple95Z28; 09-08-2009 at 09:45 PM.
09-08-2009, 09:57 PM
#37
You would be surprised, every dyno chart I've seen with stock heads and a cam similar to the original poster's (or GM 847, CC306, etc.) peak about 5800-5900rpm (add 4 or 500rpm for the shift point)..
