Aes 390 / F1A results?
02-24-2014, 07:23 PM
#36
TECH Enthusiast
The trap RPM seems a little high too me considering you are on 28"s... Even with the 3.70s, at 131 mph, you should have been at 6000 rpms or less....
So either your clutch is slipping, you have more gear then you think, or you were going faster then what the traps indicated...
http://www.tciauto.com/tc/racing-calculators/
For reference, I trap 151 mph with 3.42/28"s and go through at 6850 rpms and that is with around 11% torque converter slip.... Not exactly apples to apples but... given the fact I lose 500-600 rpms from converter slip, you can see the difference between my rpm/mph.
With your gearing/tire combo, at 6500 rpms should equal 147 mph with zero slip...
You need to find out the discrepancy here...
On another note, I love how every one throws out that it "should" run 8s and every one runs 8s with x amount or parts/power... Things are not always like that in the real world, and if it was that easy to run 8s, everyone would be doing it. Set realistic goals.... Not goals that you have seen one or two people do and think should match them.
Give us more information, and we'll try to help you. I would get it on the dyno and give it a health check first to make sure its making the power it "should" within reason... and no, its not gonna make 1000hp like everyone is going to tell you it "should"... You do need to make sure you don't have much belt slip, no boost leaks and that the engine is running efficient... Then start analyzing the other systems of the car and determine the issue.. It can be discouraging... we've all been there.
BTW.... the air hat is KILLING you.. F series blowers do not like ANYTHING in front of the inlet.... That is not helping your "boost" issue..... Also, 4000 lbs is a lot of weight to pull... Gonna take some serious jam to trap 150 mph at 4000lbs.. Spinning the tires bad on the launch will hurt your 1/8 mph and in turn hurt your 1/4 mph.... You need to get the front half of the track down to get that 1/8 mph up.... then the 1/4 trap will be higher.
So either your clutch is slipping, you have more gear then you think, or you were going faster then what the traps indicated...
http://www.tciauto.com/tc/racing-calculators/
For reference, I trap 151 mph with 3.42/28"s and go through at 6850 rpms and that is with around 11% torque converter slip.... Not exactly apples to apples but... given the fact I lose 500-600 rpms from converter slip, you can see the difference between my rpm/mph.
With your gearing/tire combo, at 6500 rpms should equal 147 mph with zero slip...
You need to find out the discrepancy here...
On another note, I love how every one throws out that it "should" run 8s and every one runs 8s with x amount or parts/power... Things are not always like that in the real world, and if it was that easy to run 8s, everyone would be doing it. Set realistic goals.... Not goals that you have seen one or two people do and think should match them.
Give us more information, and we'll try to help you. I would get it on the dyno and give it a health check first to make sure its making the power it "should" within reason... and no, its not gonna make 1000hp like everyone is going to tell you it "should"... You do need to make sure you don't have much belt slip, no boost leaks and that the engine is running efficient... Then start analyzing the other systems of the car and determine the issue.. It can be discouraging... we've all been there.
BTW.... the air hat is KILLING you.. F series blowers do not like ANYTHING in front of the inlet.... That is not helping your "boost" issue..... Also, 4000 lbs is a lot of weight to pull... Gonna take some serious jam to trap 150 mph at 4000lbs.. Spinning the tires bad on the launch will hurt your 1/8 mph and in turn hurt your 1/4 mph.... You need to get the front half of the track down to get that 1/8 mph up.... then the 1/4 trap will be higher.
Last edited by ajrothm; 02-24-2014 at 07:29 PM.
02-24-2014, 08:35 PM
#38
I agree with what everyone has said in here. Make sure you're not losing boost pressure somewhere first. Then make a pull with the inlet hat removed and see what your boost does, it may jump a lot more than you expect.
Also, if the Aster bracket isn't aligned, I would think it would toss a belt and not just slip.
Lastly, et's in a 6-speed are tough to get optimized. It takes a lot of practice, and I'm not knocking you, just saying, you may think you're rowing gears as fast as you can, but data log a run and look at how much time you lose between shifts.
Good luck and don't get discouraged. There's more to tuning a car to get max performance than just changing the air:fuel ratio and timing. It's launch rpm, gears, suspsension, shift points.... etc etc etc. You get the point.
Also, if the Aster bracket isn't aligned, I would think it would toss a belt and not just slip.
Lastly, et's in a 6-speed are tough to get optimized. It takes a lot of practice, and I'm not knocking you, just saying, you may think you're rowing gears as fast as you can, but data log a run and look at how much time you lose between shifts.
Good luck and don't get discouraged. There's more to tuning a car to get max performance than just changing the air:fuel ratio and timing. It's launch rpm, gears, suspsension, shift points.... etc etc etc. You get the point.
02-24-2014, 10:42 PM
#39
exactly! less motor. the same or more weight.less blower. cant tell me that if his setup is actually setup that it cant get there or close due to his weight only. its damn near been done with D1's. gotta do the homework. the difference is efficiency. its gotta be thought out and tested and adjusted/checked. Its not unusual to get it running and go out for some initial testing and find out you have some work to do. that is where you are now. so....
there are a few things to address. most have been already.
get rid of the slip on the belt.
knock that 60 foot down. theres roughly .3-.4 tenths in that alone.
make a boost leak checker. see if its hissing.
dont shift at 7 trillion rpm. look at the power curve on the dyno and shift near or right above peak. or go auto ftw. even if you dont get a tune its only 75 for 3 pulls most places.
id love to see the graph on this car. the curve probably lelvels/plummets after 5800-6000 rpm. a 3.90 pulley @ 7400 rpm is 78,000+ blower RPM on a unit rated to max out at 74,000.
there are a few things to address. most have been already.
get rid of the slip on the belt.
knock that 60 foot down. theres roughly .3-.4 tenths in that alone.
make a boost leak checker. see if its hissing.
dont shift at 7 trillion rpm. look at the power curve on the dyno and shift near or right above peak. or go auto ftw. even if you dont get a tune its only 75 for 3 pulls most places.
id love to see the graph on this car. the curve probably lelvels/plummets after 5800-6000 rpm. a 3.90 pulley @ 7400 rpm is 78,000+ blower RPM on a unit rated to max out at 74,000.
Last edited by I8UR4RD; 02-25-2014 at 05:31 PM.
02-24-2014, 10:50 PM
#40
Thanks guys I appreciate all the comments. Its a hard pill to swallow when you've spent some coin and you dont get the results you expect. Im going to double check everything and try using slicks next time I go out to the track to try an eliminate the spinning (was using drag radials). Ill also go dyno the car to see what kind of power its making.