Thread: how to knock a 1/2 second off my et

Tweet

well nex race day coming up and i have decided to try to get the bucket to go a little faster.
my last and best run was 14.1 with aired down rear tires and a cool engine.
stock 500 caddy 400 tranny 355 rear gears and crappy small rear tires.
i am not going to improve the rear tires yet as 1st i am going to try a few other things as follows.
i am going to remove/back off the front sway bar(its got a nova front suspension) to try to get the front end up a bit on launch
tighten up the traction bars a bit to approx 1/4 bumper space from 1/2 inch
air down tires evenly(got a low pressure 0 to 30 gauge)
and last but not least got a bm shift improver kit to put in the car.
i leave the car in drive and it shifts at approx 4100 to 4200 rpm.
my goal is to get close to 13.6 this year.
my et limit is only 13.5 before i need a full bar so i am going to try to attempt to get close to that this year and decide this winter what to do ie faster and roll bar or stay at speed i am at.
i have a opportunity to get a decent pair of 15 inch wide used slicks if i want them but if i can now get to 13,5 without them i would try that 1st.
we kind of talked about the tires and the other racer even thought they would last me forever as he thought i would just haze them to dry them off after the water box and they would work fine even cool for me . i dont think i would barley have enough hp to even turn them

any ideas or suggestions regarding any further easy chassis mods that would improve the et.

Originally Posted by canadianal

well nex race day coming up and i have decided to try to get the bucket to go a little faster.
my last and best run was 14.1 with aired down rear tires and a cool engine.
stock 500 caddy 400 tranny 355 rear gears and crappy small rear tires.
i am not going to improve the rear tires yet as 1st i am going to try a few other things as follows.
i am going to remove/back off the front sway bar(its got a nova front suspension) to try to get the front end up a bit on launch
tighten up the traction bars a bit to approx 1/4 bumper space from 1/2 inch
air down tires evenly(got a low pressure 0 to 30 gauge)
and last but not least got a bm shift improver kit to put in the car.
i leave the car in drive and it shifts at approx 4100 to 4200 rpm.
my goal is to get close to 13.6 this year.
my et limit is only 13.5 before i need a full bar so i am going to try to attempt to get close to that this year and decide this winter what to do ie faster and roll bar or stay at speed i am at.
i have a opportunity to get a decent pair of 15 inch wide used slicks if i want them but if i can now get to 13,5 without them i would try that 1st.
we kind of talked about the tires and the other racer even thought they would last me forever as he thought i would just haze them to dry them off after the water box and they would work fine even cool for me . i dont think i would barley have enough hp to even turn them

any ideas or suggestions regarding any further easy chassis mods that would improve the et.

Bigger tires will only slow you down.

i kind of rolled that thought around too that turning the big tires may slow the car down. they shure would look nasty though

a few ideas you may or may not have already tried...

1. Reduce weight, I think its about 1/4 second et reduction per 100# reduced. Have 1/8 tank or less of fuel, remove back seat if thats a possibility, remove spare tire and anything else from your trunk.

2. Improve your launch. If you are spinning, that is a et killer

3. Make sure you are getting full throttle and have good plugs and tune up

4. Optimize ignition timing. Try a few degrees each way to find the best. If you hear 'ping' during a run - its too far - get out of the throttle.

5. After driving to the track, let your engine cool off. The oil will keep the heat longer. The best is hot oil and a cool engine.

6. Let it breath. A clean air cleaner and the least restrictive exhaut as possible.

"remove sway bar to get it to launch?" don't think so...

You've got to look at what the car is doing right now to be able to know what your next steps should be. Questions you need to answer are:

1) Is the car spinning excessively off the line, or is it bogging.

2) What are your 60 foot times.

3) What are your reaction times. It is real easy to leave a few tenths on the starting line. (I used to race against a guy who had consistantly winning cars. Every darned car he owned kept trophying. Then we realized it wasn't the cars so much, it was him......he was just a really good driver , he made them fast )

4) What is the car turning in the lights

5) How does the car launch. are you wasting HP with suspension not "working."

6) Put lots of air in front tires and less in rear.

Have someone else drive the car while you watch it. See how it looks launching and going down the strip. Rather than going for 1/2 sec in one shot, go for 1/10's in little steps.

Finally, how are your starting line rpms? Is the torque convertor holding you back?



And it could be that adding HP is what the car needs, as it may have simply reached its full potential with the current setup.

When all else fails, put the laughing gas to it.



Don

Originally Posted by t0oL

"remove sway bar to get it to launch?" don't think so...

I was thinking that if you removed the front sway bar ,that it would help your launc also?Air your front tires up to the max air pressure ,and if you are using street tire in the back do keep them at the recommended tire pressure also do not deflate. Deflating the street tires in the back will only screw you up.You want maximium tire contact and deflating a street tire ,or over inflating will give you less tire contact.Slicks ya you could run 12psi or even less.Also try staging shallow.This will give you a "running" start when you trip the beams.And tires,you can do a lot with 10" wide tires.

You could put lighter springs/weghts in the distributor (curve kit) mr.gasket
makes them about $10.. I believe it's 1/10 sec per 100#
Exhast cut outs are cheap & will eliminate some back pressure,just check your plugs & make sure its not too lean.

Get a pretty young thing about 5' tall and 100 lbs to drive it for you.

With 3.55 Gears, I think a taller tire would improve your ET. Those 500s are all about low RPM grunt, hence the shift at 4200. I think a virtually taller gear via the taller tire would help you. Might help it hook up better too.

Pat

too many questions not enough computer time
don some spin with the tires aired down, tire spin out approx 150 to 200 feet off the line with tires at normal pressur(darned scary)
our timing syst has no reaction or 60 ft but for an example i raced a chev pickup with slicks and a strong 406 a couple of times(consistent 13.5 truck) he would holeshot me but i would start to catch up after the 1/8.makes me think there is more there.
last run 14,1 and close to 100 mph
starting line rpm 800 and punch it- if i load up much more against the trans then the spinning gets way worse. welcome to a high tourque engine
i know that a good set of slicks would probably bring me there and beyond from what i have seen but i was 1st goign to play with the chassis before i go any further re tires.
i do agree with stu though i think taller tire may be a good start as i have 31 inch street tires and it makes it launch on the street better. i was running just little 26 inch tires on the track
this is all just bench racing as i do think if i went and got a good set of 10 or 12 by 31 slicks and a higher stall convertor from stock that 13.5 would be there and gone easily.

Sounds to me like the launch is where you need to beef it up a little, especially when you say once the car starts moving it was catching the other guy. Those Caddys are torque monsters, so you need to take advantage of that.

If you can borrow someones slicks, try that. I agree with the guys about the taller tire size too. At 800 rpms you are just idling off the line, slicks will allow you to launch it harder.

Another thing that will sound dumb, but you want to make sure your carb is opening all the way. After I got my 5.0 in my Jeep I found out after driving it for a few months the carb was only coming open 3/4 when floored. I set up the linkage all alone, and had nobody there to stomp on the pedal while I looked at the carb. What a difference that extra 1/4 made.


Hey, you're having fun.........that's the real importand thing here, and you are out there on the track, where most guys never actually go.


Don