1/4 mile launching techniques?

[Paul Workman]

Just curious to hear comparisons between launching the ZR-1s w/ stock dual mass FW and 3.45 rears vs. 13-18# (aluminum or steel) single mass FWs and 4.10s. Let's not narrow it to experiences w/ drag radials, but rather experiences with either gear sets on either street or drag radials. Any observations/recommendations?? And, hey...If someone wants to include some big inch LT5s, tho most of us can only dream about such things, I'd read your comments with interest too! (The more the merrier, I recon!)

P.

[jonszr1]

paul ,here what i found out with my white 92 that had a stk fly wheel and then got a fidanza . the car has 392 gears . with street tires dg3 i found that the best tire pressure was 24lbs . tried to fry them with a good burnout , but still had to leave no higher than 2200rpm and slowly push the gas peddle down to the floor (ie took about 30 ftfrom the start)then i found short shifting 1-2 @55oo really helped stop the spinning i got when i shifted at 6800. i also found that going to hiem jointed rear suspension part helped as moved alot freeier than thestk stuff did . i also took the links(upright) out of the front sway bar which helped weight transfer . burnouts are a lot easier with a line lock (pete i will bet could get you set up with one .by the by PETE is hands down the best zr1 drag racer. he has through a lot of trial and error got the tricky launch of ours cars wired . i would buy him a couple of beers and ask obwhan his secrets . with the fidanza that i have in both the black and white car i can raise my rpms up to 3300 with the mt drag radials , much lower and she boggs bad due to lack of stored inertia compared to the heavy stk flywheel . i also found that the mt 315x35 drag radials really dont work alot better than street tires . the compound is too hard . i just took delivery on the new nitto nt05 drag radials , and these tires are glue, i would put them up with the hoosiers for the best drag radials for our cars . i am going to test them for the first time tomarrow and can let you know more about them after i get back if you like. if you have been to the strip with your zr1 you will find it tons of fun blowing the unknowing minds how fast our old fat butted gals run . i have no experience with the 3.45s at the strip as the black car has 4.10 again pete could help you here as he did the majority of his runs on 3.45s . tire pressures with the mts were between 16-19 lbs . but save your dough for the good drs .jmho,goodluck

[Scrrem]

Great write-up!! Doing my clutch and FW tomorrow, I'll be putting these tip to use very shortly
Rich

[LGAFF]

The book in the pizza box gives some hints on drag racing and X cross:

Launch at 1700-2000

Use upshift light to shift at 5800 1-2

5900 for third......


They also note to use Sport to reduce wheel hop.


Also they state for Xcross to set front tires at 36 and rears lower at 32PSI

[Aurora40]

You definitely want to run higher than 5,800-5,900. Even stock the power doesn't drop off that badly, and modded it will keep making power to almost 7k.

[LGAFF]

Thats for stock, I shift at 7200 or so.

[rkreigh]

the ZR-1 is a very tricky beast to launch

it takes lot of practice to get the 60 ft below 2.0

I've gotten quite a few 1.77s but more luck than anything else

because the car is setup to handle, it doensn't weight transfer all that well and the contact patch gets worse as the car does because of the IRS

gears, ,flywheel, torq clutch type, tires, ,EVERYTHING influences the lanuch but here goes on a few general guidelines

with the dual mass, you have much more intertia, 4.10 gears help, but only if you are talented enough to slip the clutch or have very good tires

I have a 390 LPE making 508 rwhp, about 430 rwtrq, with 4.10 gears, fidanza, stock clutch (that's the type of info we'll need to help advise you)

with the fidanza, and drag radials, I can come out about 3200 and let the clutch up rapidly to get that 1.77 best ET 11.47, best MPH 128

pete can do that with less rwhp due to practice and skill. lots of both are needed to find that "perfect launch point"

so here's a few more tips, with street tires, big burn outs don't help much, and depending on the drag radial or slick, getting the tires in the "water box" and getting them good and hot will dramatically help the launch

assuming those Nt05 or hoosiers (GREAT tires), you can up the launch rpms to between 3600 - 4400

the goal is to apply as much torq as possible without breaking or spinning with a clean launch without bogging the engine (very hard to do)

I find slipping the clutch really helps, but it's also very hard on it

right after your burnout, you can do a dry hop and see how the car responds to a particular launch, but the ideal launch rpm varies by car, how sticky the track is, and all those variables listed above

it takes quite a bit of experimentation. read some posts by pete and ranger (he also wrote in corvette enthusiast)

log what you do each time, and slowly ramp up the launch rpms and clutch release technique to keep decreasing the 60 ft time

every tenth there is worth almost 2 on the big end, but remember, the ZR-1 isn't much of a drag car.

my little old drag car with a solid rear (and about the same rwhp, torq as the LSV) is setup with a 4 link, solid 9 inch rear, and cuts 60 ft times of 1.35, runs 9.20s, at 142 mph, it's lighter, and has about 480 fts of torq, but it's and automatic, and really puts the power down

FYI, if you want some really good tires, I have some hoosier 17 335s for sale, 350 + shipping, I have 2 sets that I bought, and really don't run the ZR-1 much anymore (too nice to tear up)

tires and technique, those are the best two tips I can give you. tires are ez to figure out, technique takes practice and refinement, but IMHO, don't even bother on street tires, too inconsistent, and the sidewalls are too stiff.

nothing tears up the drivetrain like wheel hop. when you start to hop, back out of it and try again, it's not worth all the breakage

[XfireZ51]

Anybody have any experience launching with the GY F1 Supercars?

[rkreigh]

Originally Posted by XfireZ51

Anybody have any experience launching with the GY F1 Supercars?

yes, but in the 325 30 19 z06 side stick tire, not nearly as good as drag radials land very prone to wheel hop due to the stiff "run flat" sidewalls

I got down to 1.8 and run 11.65 at 128 by takin it easy out of the whole, I think I launched at 2800 and squeezed it

with the full hoosters, the clutch becomes the limiting factor as I can come out much harder and still hook, more like 4000, but grenaded a fresh clutch with 2k miles the first time a tried.

you need to finese the clutch action to get just the right amount of slip and then ful relase to hook up and not bog

the street tires make this harder, and avoid wheel hop or you can eaisly break things or lose control (*or a filling for that matter *