Diagnose my 1/4 mile slips please
Sep 7, 2009, 08:42 PM
#47
As of right now I have put in the Blox motor mount (the bottom crossmember mount aka roll stoper)
I will get the bushings and see if that will help make the shifting smoother.
Sep 7, 2009, 09:18 PM
#48
ya the restrictor pill, i had it all done at the same time, rebuild on exedy new syncros and sliders and bushings and clutch line so i could'nt say how much each change made but its night and day bushings seem to take out alot of the slop and they are cheap
Sep 8, 2009, 10:02 AM
#49
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Armen, later on this week we're going to the track. I'll call you and have my friend drive the car and see if its driver mod or not. Car is fine, chances are its spinning off the line, (clutch or tyres) and we'll be able to figure it out. 34+psi in cheapy all-seasons is not gonna cut at he drag strip, you loose too much contact patch -most likely we're going to have to drop the tyre pressures for optimal grip.
Sep 8, 2009, 05:49 PM
#50
Armen, later on this week we're going to the track. I'll call you and have my friend drive the car and see if its driver mod or not. Car is fine, chances are its spinning off the line, (clutch or tyres) and we'll be able to figure it out. 34+psi in cheapy all-seasons is not gonna cut at he drag strip, you loose too much contact patch -most likely we're going to have to drop the tyre pressures for optimal grip.
Yea tire psi is a huge thing. I realised that that day. The best 60 ft time I had prior to lowering it to 20 psi was a 1.7. After I lowered my tire psi to 20 I made 2 passes with it both with 1.5 60ft times. I felt the difference off the line right away. This is also with the 2 step at 6k
Sep 8, 2009, 05:54 PM
#52
Armen, later on this week we're going to the track. I'll call you and have my friend drive the car and see if its driver mod or not. Car is fine, chances are its spinning off the line, (clutch or tyres) and we'll be able to figure it out. 34+psi in cheapy all-seasons is not gonna cut at he drag strip, you loose too much contact patch -most likely we're going to have to drop the tyre pressures for optimal grip.
Its true it does spin off the line, but I dont think that should affect trap speed by that much. Its not like its pealing out all in first and second.
A perferct example is my friend with the 01 cobra. Previous time we went out I was doing 1.7 , 12.8 @ 109 (a/f in the 9's) and he was doing 2.X 60's , 13.5's @ 113 spinning out all in first and some in second! Now we went I did the low 13's @ 105-107 (a/f in the 11's) while he was doing 12.1-12.2 @ 113-114 mph 1.6 60's with slicks this time.
I have all wheel drive and only spin a little from the launch. He was only off by 1-2 mph trap with his street tires rwd slipping vs slicks this time gripping.
But yes, I am welcome to any help I can get to diagnose this. If its the driver mod then so be it, but honestly I dont feel that pull up top as I did before. Maybe I got used to the car maybe not.
I ordered the shifter bushings from Buschur last night. Both the trans bushing and the shifter bushings to help with a little more precise shifting.
Also one other thing gets me puzzled. Lets say I am a terrible driver. But even a terrible driver will do better on a faster car than a slower car. In this case I was doing worse with a better a/f ratio than when I was flooding the engine with a/f's in the 9's.
Last edited by BluEVOIX; Sep 8, 2009 at 06:19 PM.
Sep 8, 2009, 06:44 PM
#54
I'm not blaming the tune, but maybe there is something with the car that is holding me back.
I'm going to do a compression test this week. Just to double check and rule that out. So far I have done a boost leak check and everything is nice and sealed.
Sep 8, 2009, 06:51 PM
#55
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MPH has a LOT to do with how fast you shift.
You need to cut good 60' and shift good in order to make ANY car run how it should. Evo's especially on stock turbos gain most their advantages off the line as opposed to after the 1/8th mile.
You need to cut good 60' and shift good in order to make ANY car run how it should. Evo's especially on stock turbos gain most their advantages off the line as opposed to after the 1/8th mile.
Last edited by inco9nito99; Sep 8, 2009 at 06:55 PM.
Sep 8, 2009, 07:29 PM
#57
My car with just catback (Tanabe) exhaust ran 1.8 with 13.3 104 trap. Than turbo back exhaust and air filter ran 1.8 13.1 @ 107. Then with huge boost leaks (TBE o2housing, tune mbc) ran mid 13's @ 104-105 mph traps. Then with leaks fixed but rich a/f ran 12.7 -12.8 @ 109 mph all day long and with power shifting 110 trap. Then with a/f in 11's ran 13.0 @ 107 once and the rest 13.1-13.3's @ 104-106's also a couple 13.5's where I missed 3rd.
It just doesnt make sense. I mean seriously, even if I was the worst driver, with power increase the traps should increase as well and not go down. My only guess at this point is to do a compression test unless my taller 245 45 17 tires are hurting performance.
In the mean time I'm going to make a video of myself doing a quick run. Showing how I launch and how slow/fast I shift. Also I'll go with you guys on a Sunday and let a good driver run my car.
Last edited by BluEVOIX; Sep 8, 2009 at 07:31 PM.
Sep 8, 2009, 07:48 PM
#58
I'd say with your old tune, your car was running rich, but well, so you were only down on power a little from what you could be. With the new tune being a lot leaner, you're probably knocking, which can easily zap your power down below what you had before. My opinion is that there's no substitute for having a good logging setup and doing the tune yourself - otherwise you're just flying blind.
Tom
Tom
Sep 8, 2009, 08:00 PM
#59
I'd say with your old tune, your car was running rich, but well, so you were only down on power a little from what you could be. With the new tune being a lot leaner, you're probably knocking, which can easily zap your power down below what you had before. My opinion is that there's no substitute for having a good logging setup and doing the tune yourself - otherwise you're just flying blind.
Tom
Tom
I'm not blaming the tune, I'm blaming the car mechanically. Something must not be right.
Sep 8, 2009, 08:25 PM
#60
I'm not "blaming" the tune per-se, and I believe you when you say everything was fine 'n dandy when you got the tune. But then you went to the track on a different day, with different weather conditions and drove the car in a way that (I'm betting) was wholly unlike the way the car was tuned. Most tunes are done as a full pull in 3rd or 4th, on a dyno or on the street. That's not how drag racing works, and I've personally seen massive differences between knock on different days and under different circumstances with no changes in the tune. Your tune should have picked up 20-30 HP up top, and instead your drag runs indicate less HP than before. With no mechanical changes and only a short time between tune and drag strip, there's no other explanation other than knock, which I've personally seen zap 50 HP.
Folks that "get tuned" and go out and run great times either have a car that's very knock-tolerant, or they've got a very conservative tune and hit just the right weather combination. As I said, without a good engine management system where you can see what's going on and tweak the tune as you run, you end up just where you are now: "something's wrong" and there's no real way to diagnose what.
Tom
Folks that "get tuned" and go out and run great times either have a car that's very knock-tolerant, or they've got a very conservative tune and hit just the right weather combination. As I said, without a good engine management system where you can see what's going on and tweak the tune as you run, you end up just where you are now: "something's wrong" and there's no real way to diagnose what.
Tom