Drag questions

[Pitbull1052]

K so this past saturday went to Thornhill with some buds just to run for fun and I was mostly trial and error testing my shock set up. So to tell you what i have then my quesitons.


1989 GT
347 9.5:1 compression
Vic Jr heads
1:6 rockers
Systemax intake
42lb inj
73mm mass air
90mm TB
Long tubes
custom x pipe
T-56
4:10's
275/35/18 KDW DR
coil overs up front
H&R springs on the rear
Strange 10 ways

So my best run was

12.9 at 108
my reaction time was a .01
2.02 60' I know not the greatest



I typically keep the shocks set right dead in the middle, so I make my fronts 1 notch stiffer took the rears to as soft as they'd go, i chanced up my launch RMP several times anywhere from 3500-5000 and nothing really ever changed time wise, it was either a 12.9 or a 13 flat. I know my car is faster than that. Was it mostly the heat and humidy or ????? any idea on setting the shocks? Also i was running right about 27lbs in the rear tires...... they were hooking really well out of the hole then i'd nail second and they'd break loose. I was in the box for a good 10-15 sec heating them up.


Any advice would be greatful


Thank you,


B

[Jeff88coupe]

18" DR's are what your running correct?

To get a DR to hook well with a stick isn't the easiest...especially 18" dr's with very little side wall height. Start by putting the front struts to full loose to let the nose of the car rise as fast and high as possible to let the weight transfer to help plant the tires. Rear single adjustable shocks usually work good set on about 5 or 6. The rear end of the car should be firm when you push down on it..don't want it to squat easy. DR's need the suspension to keep the car's weight transfered to the rear to keep them planted to stick. You are probably unloading the rear on the shift which is letting them spin.
The best thing I can tell you to help you hook is get another set of 15"x8" (at least..can fit up to a 10" rim on a fox) for the rear with a set of slicks (like 26x8.5's or 26x10's) for the track.

[5.0calypso93lx]

I'd think it's probably the heat. With a 2.02 60 foot, 108 trap seems a bit low. Ever had the car on a dyno?

[Pitbull1052]

I'd think it's probably the heat. With a 2.02 60 foot, 108 trap seems a bit low. Ever had the car on a dyno?






I was thinking the same that the heat had something to do with it. and yup Adam tuned it. 356 hp and 365 tq....... i'm getting ready to switch to his software and see if he can get a little more out of it....... i trapped once at 110 but it put down a miserable 13.3......

[Pitbull1052]

18" DR's are what your running correct?

To get a DR to hook well with a stick isn't the easiest...especially 18" dr's with very little side wall height. Start by putting the front struts to full loose to let the nose of the car rise as fast and high as possible to let the weight transfer to help plant the tires. Rear single adjustable shocks usually work good set on about 5 or 6. The rear end of the car should be firm when you push down on it..don't want it to squat easy. DR's need the suspension to keep the car's weight transfered to the rear to keep them planted to stick. You are probably unloading the rear on the shift which is letting them spin.
The best thing I can tell you to help you hook is get another set of 15"x8" (at least..can fit up to a 10" rim on a fox) for the rear with a set of slicks (like 26x8.5's or 26x10's) for the track.





yes sir you are correct 18x10 BFG KDW's........ and awesome I was doing the exact opposite as what a site i found was saying to do lol it seemed like it was blowing them off at the top end of 2nd before nailing 3rd, and oh yea i was shifting around 7k.... this was my first time at the track with this car and I have very limited track experience maybe been down a half dozen times prolly a dozen now.......... enough that i'm not nervous or shaking by the time i get done lol

[Jeff88coupe]

What rpm was your peak HP at on your dyno curve? 7K seems a bit high to be shifting at.

[Pitbull1052]

I'll have to check my dyno sheet i want to say it was around 5600

[5.0calypso93lx]

Are you using the stock tach? Either way like Jeff said, I would bring your shift points WAY down. You want to shift where you find the median between making good power in the gear you're currently in while also being in a good spot in the powerband in the next gear.

[Pitbull1052]

Are you using the stock tach? Either way like Jeff said, I would bring your shift points WAY down. You want to shift where you find the median between making good power in the gear you're currently in while also being in a good spot in the powerband in the next gear.





Heck no there's not one stock gauge in my car lol i've got a autometer colbolt in the dash and a colbolt pro with shift light on my pillar........ that could be the reason that a turd 300zx beat me at the big end it was right when i shifted he leaped about a nose on me

[Pitbull1052]

here's what i've got

http://www.autometer.com/cat_accessoriesdetail.aspx?vid=199

[5.0calypso93lx]

If it's an aftermarket tach it should be pretty accurate. I would start shifting at 5500 and make a few passes then up the RPM's by 100 till you find what your car likes best.

BTW, reaction time plays no role in your overall E.T.

[331lx]

What cam is in this car maybe i missed it. The heat probably hurting ur trap speed, my stock coupe with 3.73s went 12.6@105 so u have a lot more left in her I think

[Pitbull1052]

cam is a custom ground flow tech built for boost .600 lift i'll bring the specs with me tomorrow and post up, i had a couple 108's, and a couple 110's....... and i think so too it was so hot it wasnt even funny, i bet at 11:00 it was still 90 out......

[331lx]

My guess is that setup should trap 120+

[90fastgt]

Have you ever weighed your car an that trap seems low to me also the heat definitely played a big role in your time

[leroy93lx]

What are your front coil over spring rates and length? What I see is no weight transfer. Your springs are stiff and even on the softest settings your shocks and struts will never be utilized like they should. I trap 105 running 12.9s with 100 less rwhp than your car. The big difference is I have 1.7 60s. I also think you should be running about 15-18 psi in your tires. Ride the clutch out and shift at peak power every time also. That car should throw down 11s with ease.

[2Fast4You]

What rear upper & lower control arms are you using?

[Pitbull1052]

Have you ever weighed your car an that trap seems low to me also the heat definitely played a big role in your time




I have not weighed the car ever it's a stock body full interior gt.......

here's my cam specs and peak hp

intake .598
exhaust .578

max hp 353.61 @ 5500
max tq 363.56 @ 4500


It's at 9.5:1 set up for boost which i hear a V3 may be in my future

[Pitbull1052]

What rear upper & lower control arms are you using?





bbk boxed uppers and lowers....... i've got a set of double adjustables just havent put them on yet

[Pitbull1052]

What are your front coil over spring rates and length? What I see is no weight transfer. Your springs are stiff and even on the softest settings your shocks and struts will never be utilized like they should. I trap 105 running 12.9s with 100 less rwhp than your car. The big difference is I have 1.7 60s. I also think you should be running about 15-18 psi in your tires. Ride the clutch out and shift at peak power every time also. That car should throw down 11s with ease.






That's what i thought too before it had a higher comrpession 347 it was at about 12:1 and it put down 11.2's at 124 ish which i would be tickled to death with, i'm not sure of the spring rates i'll get the numbers off of them. Basically i think it was the heat, the fact that i had my shocks set exactly backwards (thanks strange) according to their web site, and a not so hot 60' but then again it was the first time ever i had had it on the track, first time on these KDW's which being 18's don't help me much but they were a great price so i can't complain there and shifting at too high of an rpm, i think if i shift sooner i can be in 4th before i hit the very end and not scrub off too much speed. I ran a few ricers and I know this 300zx i ran i had him out of the hole, i had him at half track and then i shifted to 4th and he blew past me at the line.



Thanks for all the info guys great stuff guys! I hope to run at edge next so if you see me and care to give anymore pointers just stop by i'm Brad performace red 89 gt had FR's on it has black ROH's on it right now......