99blancoSS

iTrader: (115)

Ok I have a 99 SS with stage 2.5 heads and a tr224 112lsa cam, 373 gears. It put down 410 on a mustang dyno wich is around 440 on a dynojet. My car is a full weight t-top with a little added weight (stereo and soundproofing)and I usually race with a full tank. I'm about 265.

At the track my car is very slow. I'm trying to figure out if its the way I drive it or if the car has a real problem.

I trap at 108 with 13.2 to 13.4 ets. Always at 108mph. My 60's are bad. They were 2.4 (w/108 mph trap) and I got them down to 2.1 with the same trap speed.

I shift at 6k rpms (rev limited to 6300 rpms). I leave the line just above idle in order to get the 60's down. Is this the real reason for my slow times? My launch rpm is 2k or less or I smoke the tires.

My clutch (Textralia) makes noises but I dont notice it slipping majorly. Its got about 10-14k on it. Dont want to spend money in the shop if there isnt anything wrong. Those of you with a lot of power how fast do you run from idle?

rocketman442

iTrader: (8)

With that kind of power your traps should be alot higher. You would also benefit from getting your 60's down a good bit either with practice or tire, both would be best though.

99blancoSS

iTrader: (115)

I hear this all the time. People that run 11's dont leave the line at idle do they? This is a 6 speed not a stalled auto. Is it the fact that I'm not setup to run low 12/11's?
I know with that much power I should be trapping higher but dont I also need to be leaving the line at a much higher rpm in order to attain those times and trap speeds?

SPEEDYws6

iTrader: (9)

If you have made changes to the car since the tune it could be off, if your running street tires you may still be spinning badly down track. When I first put the 100 shot on my car it was still on street tires it only went .2 faster cause it was spinning down track. I changed the tires and nothing else and it almost went a whole second faster than the motor times that same day (would have if it had been geared right)

So I say get a good set of tires out back, and just get a bias ply tire if you already have wheel hop. The soft sidewall kills alot of wheel hop. I have broken more parts on drag radials and street tires than I have drag slicks because of the wheel hop I get with them.

tektrans

iTrader: (23)

Even with the shitty 60' your trap speed should be around 10 mph higher with an m6. Tell us about your set up a little more:
Tires? suspension?
Your shift rpm seems a little low to me, what rpm are you coming through the traps at?
With all that extra **** in the car and a full tank of gas plus your weight , what is your race weight?

99blancoSS

iTrader: (115)

I dont know my race weight. I have nitto nt-01 out back 18x30x315. They dont hook at all thats why I leave the line at such a low rpm. Konis / slp pro rate springs.
Not sure of the rpm at the trap. I'm not really setup for drag racing but figure I should still pull better times than I do.

coop5885

iTrader: (2)

throw a set of drag radials on it and see what it does. You can get a BFG in that size, and it will make a world of difference.

rocketman442

iTrader: (8)

Would be best to get a spare set of 16's to put some stickies on, lighter and more sidewall.

99blancoSS

iTrader: (115)

I understand with limited traction my ET will be not so good. I know how to improve traction and 60's.

But the real question here is my trap speed.

Should it be higher given the fact Im leaving the line at low rpms?? That is the main question.

My car is about 3800 lbs near as I can figure. 3439 plus me and the stereo and full tank.

rocketman442

iTrader: (8)

I would say bump up the shifts a little and try that also. That RPM is about the optimum shift point for a bone stock LS1.

tim99ws6

iTrader: (31)

dude, you need alot more than bumping up shifts. you're pulling about 14mph slower than me in a full weight WS6 with 430rwhp. You need to re-dyno and check to see that the motor isnt hurt, and that the clutch is still holding. what DA are you racing in? what is the elevation at the track?

Either your track is like on the tip of the mountains, or your car/motor is hurt/having problems.

tim99ws6

iTrader: (31)

Even if he was spinning through the 1/8, he should STILL trap well over 108 if he is truly putting down 440ish to the wheels.

99blancoSS

iTrader: (115)

Can clutch slip be semi undetectable? I know the throwout bearing is making noise and the clutch is worn a bit I would say. It makes some noises and chatters real hard once in a while in 1st. But once it engages I cant tell if its slipping. I look and feel for it but it seems ok. Except for the to bearing issue. Car isnt smoking at all either. I guess I have to get it into the shop. Its money I didnt want to spend. Money that could go towards a clutch if I need one.

Honestly the dyno this car was on has cars with less power going low 11's. The racers that were there and saw it and have seen the graph subsequently have all said 11 teens. Somethings up.

ABA383

iTrader: (1)

My guess would be if the clutch was having issues they would've surfaced on the dyno and your numbers would've reflected it...Find out from the dyno guys what "weight" they had the rollers on the dyno set at...I think the standard on a Mustang dyno is 1550ish pounds...I have seen people manipulate the weight with a key stroke and change the "weight" to 2000 pounds making your hp artificially much higher than it really is...I'm not saying its happened in your case...Just something you should look at...I make between 362-400rwhp depending on dynos and I trapped 118 last year...I would expect at least 10 mph more than you are trapping now...The dyno doesn't match the track mph...

--Alan

99blancoSS

iTrader: (115)

It goes in tomorrow. I know he sets the weight according to the car and its different for every vehicle he does. We'll see what it does on the dyno tomorrow and what he can find.

99blancoSS

iTrader: (115)

Ok well its about 20 less hp and tq than when it was dynoed last. This could be accounted for (according to tuner) by the fact that it was dynoed in Feb and its now August. Big difference in weather here in Oregon.

He also checked with a racing guru. My lack of trap speed and ET is accounted for by my lack of traction according to him. Tire spin is cutting down the length of the track for my car to run. Obviously tire spin will greatly effect the et but according to him it also effect the trap speed as well.


He didnt find a thing wrong with the tune. No KR was present and it looked good to him. He suggests tires and maybe a driver mod.

He also reminded this is Oregon and cars generally dont run as fast here as other places. I've been told this by numerous racers.

So I've got a line on some 16" wheels for $50 for the pair and the tuner will see what he can get me some M/T's for.

rocketman442

iTrader: (8)

Unless your spinning thru the traps you MPH should still be pretty high though

tim99ws6

iTrader: (31)

In theory, you will MPH higher in the 1/4 spinning, than if you were to dead hook. It's been proven, but outside factors(like drivers) sometimes skew this theory.


Also, depending on the DA where you run at, it is a VERY valid point that your car could run slow simply due to the elevation and heat/humidity at the track. There is a website you can pull the EXACT DA of you run if you still have the timeslip. Do you still have the exact timeslip?

SiL3NtXWS6

iTrader: (17)

with a 2.5 60' , i ran virtually the same mph as i did with a 1.7 60'

SPEEDYws6

iTrader: (9)

My car trapped 111 on street tires, and 121 on slicks. The car was spinning after every shift with street tires and never had a chance to gain any trap speed.