Launch Methods

[Beyond]

I've been asking a number of people about this and was wondering what some of you might say about it..

At what point do you quit trying to "dead hook" a doorslammer and try to get it "up on the tire"? When you talk to the pro-mod guys, the things they are trying to accomplish at launch, and getting down track are a lot different it seems than the slower cars. I'm just kinda curious when you stop trying to dead hook one and you start working on tire speed, etc.

Anyone care to go into detail on this subject?

[Chris Uratchko]

John,

I don't think it's a good idea to dead hook any car. Really, what happens when you dead hook? You essentially 'stop' the entire drivetrains momentum... and now the entire system has to recover from that..... and there is not time for recovery.... that's ET just blowing away in the wind.

The key is to obtain a small amount of spin balanced with momentum out of the gate... When you see folks with incredible 60's based on their combo... that is when they find the perfect balance of wheel spin, versus momentum out of the gate....

Anyhow that's my take on it, and my experience.

[Beyond]

This topic is one that I often find people starting to get real quiet when I bring it up LOL - it is nice to see some people aren't skeered to talk about this stuff.

What do you look at besides the obvious 60/330'et and driveshaft rpm. Do you guys also watch your shock travel/front and rear to try and get a handle on it?

What steps do most people take when trying to deceide what to do - for example Chris - the bumper dragging wheelie in your avatar, what did you guys do after that to get ready for the next pass?

[Chris Uratchko]

John,

That was a 1 time thing that car will never do that again. I ran first round qualifying, and I must have gotten in some oil, or something because it just spun... so I figured the track was junk and loosed up the front shocks 2 clicks... and that was the result. 2 clicks back to where we always run it, and it was back to 1-2 foot wheel stand.

As for what we monitor, all of the above. We monitor how much the rear of the car rises, how much wheel spin we have, how much it carries the front end out and we make shock judgements based on the timeslip, versus the car data... most of my racing experience is with a small engine so I'm balls to the wall on a launch in terms of power... I'm not holding anything back on a launch. So that scenario, makes some things easier for me, and some things more difficult. To date, I've been 1.22 60', which is pretty good for a n/a small tire car.

Often folks get quiet for 2 reasons. One, is that they are not there yet with their own stuff. Two, is that it took so long to find the proper launch technique that they really don't care to share it...

It takes a lot of testing to figure it all out forsure,.. but I'll say this. There is much more "in the engine" to a launch, than most folks give credit for. It ain't all chassis. It took me a long time to figure that out................

[85Camaro]

I agree with the no dead hook, My car would always dead hook on launch and the 60's were very poor lost a lot of engine RPM on the launch, The one time it did 60 it best was minor tire spin off the line. Had I realized that dead hook was a bad thing (in my case at least) way back when could have got the car to run a whole lot better Just my .02 :|

[Beyond]

Good info... Have to agree Chris - that 1.22 is very impressive. Interesting point about how much the engine affects launch, I'm sure that's the case on a N/A car more so than a power adder setup.

Just one more question if you don't mind.. How do you guys measure tire slippage?

[gilsbachracecraft]

slip is measured w/ some sort of datalogger in rpm.it is a must for getting the full potential out of your combination.racepak, autometer and edelbrock sell dataloggers (just to name a few)but are a little expensive.autometer also sells a tach with a drive shaft sensor and is downloadable that is reasonably priced.every combination will like a different amount of slip you will find this in testing.chris dead on on all accounts.how much power ,rpm and how fast you ramp the power back in is just as important as your chassis adjustments even on power adder cars, probably more so.

[Beyond]

So you guys measure it by watching the driveshaft RPM curves is what you're saying right? Nobody is using like a ground speed sensor or nothing like that?

[gilsbachracecraft]

correct! 8)

[Chris Uratchko]

I get accurate data from the driveshaft... You can see the graph climb and come back down when the tires begin hooking up... depending on when the graph starts accelerating, then decelerating, to the point where it begins climbing again is wheel spin.

[Gary Kubisch]

Chris
What frt shocks are you using?
Also,I assume your car is 50% or so on the nose?

[Chris Uratchko]

Gary,

I have no idea what my weight bias is right now. I just keep trying to get my weight down but I can guarantee I'm nowhere near 50 percent in the front.... just can't do it making a car this light... it's a 2810 pound car with me in it and no balast in it.

I'm doing some weight removal right now but it's all in the rear of the car. Can't get anymore out of the front really... carbon brakes? LOL.

I use Strange coil overs in the front. They are single adjustable but I'm selling those and putting double adjustable on it.

[Maliboost]

get it "up on the tire"

Not to crash the party here, but I have heard this term quite a bit, but dont understand it. what does it refer to?

thanks
Bob

[Chris Uratchko]

Bob look at my AVATAR!!! :smt005

[Gary Kubisch]

2810 w/driver.........Kinda makes me laugh when I see people w/ Camaro's thowin' more power at them when they still weigh 3400-3600lbs.

I've been unsure of a C/O on the frt.,I was under the impression they wouldn't allow the travel to transfer the weight and get the car to hook,But you car seems to be good evidence to encourage me to go that way.
I'm replacing the old dbl adj Koni's that I had in the frt. with dbl. Afco's to match the rears.
I WAS going to retain the Moroso spring but have been trying to decide for sure.
The springs I had in the car were 17lbs for the set,I'm sure the C/O's are lighter.
And on top of all this I can set the ride height easier......

A friend who runs IHRA Top Stock w/ a Buick was telling me when he tried a set of C/O's on his car,Like me,He was skeptical and feared it would not work.Told me the frt suspension barely moved,But at the track the car went for the bumper,So one adjustment and the next pass was 1.26 on a 9'' Radial slick.......This was with the QA1 set-up which he thinks the Afco's are even nicer,Just weren't available when he switched.

My car car was 3430 w/driver and 54% on the frt,It worked well but I never really got agressive in th 60',I kept the "tight" converter in because the car was consistent and I was afraid to change anything.Best 60ft was only 1.31 which I thought was decent until my buddy went in the mid 1.20's w/ his Top Stocker.

Sorry for the rambling........It's winter
With the 100 + lbs I have been removing from car,It will be close to 3300 w/driver,And 52% on the nose,I'm really anxious to move some of what has been removed to the rear and try the car at 51% but I have plenty to do before that

[Beyond]

Gary - don't expect a lot of weight savings from a double adjustable coil over w/springs vs Moroso springs and conventional shock, it's only like 11lbs total savings for both sides and you will probably give up at least a little travel depending on how you set everything up.

The real weight savings comes from using a lower a-arm that utilizes a heim type mount for the coil over vs the traditional spring seat/pocket.

You can figure that the swap from standard a-arms to tubular along with coilovers to save approximately 37lbs.

[Chris Uratchko]

The key is getting the right arms too.... I had Next Generation Racecars build my arms and they are all 4 around 8-9 pounds, heims and all. Thin wall chome moly. The heims work a lot better than bushings, and are far more adjustable. Lost the stock type ball joint in favor of a nascar type heim ball joint.

11 lbs is 11 lbs.... find 11 lbs in 3 spots and that is 33 lbs. Even finding 2-4 pounds, if you find that 3 or 4 times that all adds up.

Rack and pinion saves a ton of weight... lose the iron steering arms on the spindles... make them out of thin wall chrome moly.

I've not left anything untouched. My car with stock floors, no swiss cheese anything, all glass windows with regulators, all steel except hood and front bumper, stock trunk, stock spindles, etc, and a chassis with tons of bars will weigh 2750 when I'm done this winter. That's not easy with a 69 camaro. At one time my car weighed 3550 with me in it. So I've lost 800 pounds just workin away....

[Beyond]

Speaking of weight, anyone done much research on front tires? I've got the Mickey Street Type front tires and I think I can shed a few lbs switching to the Drag version. However I've been seeing these new ads for the new front tire Toyo has, anyone have an idea what those weigh? Wonder if they really do reduce rolling resistance?

[Gary Kubisch]

My stock a-arms were 12lbs ea. for the lower and 9lbs ea. for the uppers...42lbstotal.
New tubular uppers w/ heims are 5lbs ea. and lowers are 9lbs ea.....Total is 28lbs.

So if I can remove 11lbs from the shocks and springs that is a total of 25lbs....I'll take that but I'm curious as to how you arrived at 37lbs,That would be better.

And Chris.....
That's what I'm working on,Many people were surprised when I would tell them my car was 3430 w/driver........Guess I should just say 3600lbs and pretend I'm making more power than all the other Buick guys :lol:

[Beyond]

My stock a-arms (Nova) were apparently heavier than yours and my tubular lower arms are lighter (no spring cup).

Stock Arms = 46.4lbs
Tubular Arms = 20lbs
A-arm Savings = 26.4lbs
Shock Savings = 11lbs

[Gary Kubisch]

Wow......You got a little more for your money than I did in the a-arms.

I keep tellin' everyone $900 to save 14lbs and I'm gettin' ready to pack on about 15lbs in food this weekend........

Who's a-arms did you use?

[Beyond]

I used the ones from David Lemmond - http://www.davidlemmond.com

Yeah, ain't it funny how much a racer will spend on taking weight off the car but not off himself LOL :-D

[Gary Kubisch]

I considered the same ones.......Called,Got the voicemail,Left a message,And never rec'd a callback so I kinda for got about them.

[Racefab33]

Gary, Sorry I missed you. There were a few days that I had a bad machine. I could not retrieve messages. The best time to get me is after 5:00pm central. I don't offer A-arms for your car yet. But still hate that I missed your call.

David

[footbraker]

How am I doing? :wink:

http://members.cox.net/10.90streetcar/edside.JPG

http://members.cox.net/10.90streetcar/edfront.JPG


1.31 60 foot, DEAD HOOKING, off the footbrake at 2400RPM, 3860 lbs., 59%/41% F/R weight bias, stock type/bolt-on suspension.

And to think it's done WITHOUT tubular A-Arms, trick springs, drag shocks, anti-roll bar, rim screws and tubes!

[Chris Uratchko]

Hey that's a good hooking car!! Nice Job.

[Gary Kubisch]

How am I doing? :wink:

http://members.cox.net/10.90streetcar/edside.JPG

http://members.cox.net/10.90streetcar/edfront.JPG


1.31 60 foot, DEAD HOOKING, off the footbrake at 2400RPM, 3860 lbs., 59%/41% F/R weight bias, stock type/bolt-on suspension.

And to think it's done WITHOUT tubular A-Arms, trick springs, drag shocks, anti-roll bar, rim screws and tubes!

Another half a second and you've got a good IHRA Top Stocker....... :wink:

[steel town]

WOW footbraker thats awsome I have a 3600 LBS stock chassi 80 CAMARO and I'm fighting to go 1.55 60's I think my converter is junk though .I have a 68 camaro in the garage I'm cuttting up right now I'm hoping to get it down to about 27or 2800 lbs that should get me into a beter time ,maybe I should just forget the pump gas exhaust and street tires and just go racing there doesn't seem to be many cars on the street anymore anyways .

P.S is that all motor

[footbraker]

All motor, through a full 3" exhaust!

Pump gas 468, turbo 400, 8" converter and 4.10 gear.

[steel town]

I'm impressed . I,ve gone a 6.9 @ 99mph in the 1/8 only once last summer but I shut it down and never got a chance to back it up . The run befor that I went 125 mph in the 1/4 with only a 1.65 60ft but my car won't ET like yours not even close must be a nice piece . Ive got a 406 with ported darts and flat top pistons 400 turbo and an 8 converter 456 gears .I just changed the gears to 488 cause I broke the 456's .I don't know if I'll give it another try I'm hoping to get this 68 camaro done in time for summer

[MCMIKE]

Speaking of weight, anyone done much research on front tires? I've got the Mickey Street Type front tires and I think I can shed a few lbs switching to the Drag version. However I've been seeing these new ads for the new front tire Toyo has, anyone have an idea what those weigh? Wonder if they really do reduce rolling resistance?

Looking for some info on this myself. My front Pro Stars with the Mickey Thompson 8 ply sportsman fronts weigh 27lbs each.I'm looking for weights of the front Aluma Star and a Moroso DS-2, or the Mickey Thompson ET fronts.

[gilsbachracecraft]

i weighed a set of the old style aluma stars w/mickey sportsmans against a set of new alumastars w/a hoosier front runner a few months back.the hoosier and new alumastars if i remember were 22# lighter(11 each side)

[Beyond]

Do you think most of that was the rim? I sure like the looks of the new Alumastars, just don't like the price :-(

[MCMIKE]

I found tire specs on the web but no weights for Weld Wheels.The Sportsman 8-ply weigh 19 lbs. each, and the DS-2'S weigh 12 lbs. each.So that's a 14lb. savings without the rim factor.

[Beyond]

That's a pretty good bargin lbs for $ especially considering it's also rotating weight.

[MCMIKE]

The key is getting the right arms too.... I had Next Generation Racecars build my arms and they are all 4 around 8-9 pounds, heims and all. Thin wall chome moly. The heims work a lot better than bushings, and are far more adjustable. Lost the stock type ball joint in favor of a nascar type heim ball joint.

11 lbs is 11 lbs.... find 11 lbs in 3 spots and that is 33 lbs. Even finding 2-4 pounds, if you find that 3 or 4 times that all adds up.

Rack and pinion saves a ton of weight... lose the iron steering arms on the spindles... make them out of thin wall chrome moly.

I've not left anything untouched. My car with stock floors, no swiss cheese anything, all glass windows with regulators, all steel except hood and front bumper, stock trunk, stock spindles, etc, and a chassis with tons of bars will weigh 2750 when I'm done this winter. That's not easy with a 69 camaro. At one time my car weighed 3550 with me in it. So I've lost 800 pounds just workin away....

Chris, how much weight will a rack save ?

[MattG]

I am interested in knowing how much weight a rack will save well. We need to pull 50-100lbs out of our car for next year.

Are there any downsides of a rack?

[MattG]

Oops... Hit reply one too many times.

[Butch Kemp]

I found tire specs on the web but no weights for Weld Wheels.The Sportsman 8-ply weigh 19 lbs. each, and the DS-2'S weigh 12 lbs. each.So that's a 14lb. savings without the rim factor.
The Weld 5 hole magnum drags are 11/2 lbs lighter than the stars I have a set of each. The goodyear front runners are over 1 lb lighter than any other tire. Hope this helps BK

[67RS/SS]

I considered the same ones.......Called,Got the voicemail,Left a message,And never rec'd a callback so I kinda for got about them.

Hey Gary,

Doing a search on tubular arms I came across this thread,I know it is old,but I was wondering what you ended up using?

Did you go with new arms and coil-overs?

Does anyone know if you could put some street miles(maybe 200-300 a year) on the chrome moly a-arms with the heim joints?

My car is 3480lbs with me ,so I'd like to shed a few pounds. Anyone know how much weight can I remove from the stock subframe?

Thanks,

Steve Rommel:)

[Ed-vancedEngines]

I have no idea what the posts on this thread are having to do with Launch Methods, but along the vein this thread is traveling, here is a couple of ideas for you to consider for removing weight on front with early GM cars.

If your rules will allow it, Buy Corvette C4 Complete front suspension from junk yard or from one of the eBay sellers. Also buy the Aluminum Master Cylinder/wlightweight brake booster, and the aluminum front brakes including caliper and disc. You can even go a little further if you are a fabricator and also buy the rear brakes too. You will throw away some of what you buy but you will get very strong light weight aluminum upper and lower control arms, rack and pinion box, front spindles that are already giving the positive castor effect, and great cheap light weight brakes.

If you get the complete front suspension from the 1989 thru the 1995 C4 vette the brake size will work in a 15 inch wheel.

You will have to fabricate a rear mount for the rear caliper but that is very easy to do and do right.

Appx cost an be $1,200.00 and lower for the full front suspension clip. That will include a big composite leaf spring which you could use but it is easier to set up coil over on it. The 4 brakes sould be appx $300.00 The Aluminum Master Cylinder with light booster will be appx $150.00 That would get you a complete well matched light weight braking system. A company named Master Brakes sells adapters to adapt the aluminum Vette Master Cylinders to most Domestic applications.

If you were to use the complete pacakage you will drop several hundred lbs. At least well over a hundred. Without the brakes the front control arm pairs including steel spindle with bearing hub weighs appx 22 to 24 lbs per side. The rack and pinion is aluminum and very light. The Master Cylinder is incredibly light.

The control arms are not a simple bolt in. Mounts for them need to be fabricated for the lower ones, and the top ones can possibly fit the factory locations with only some hole alterations. If not you fab a new mount. For the classes that allow aftermarket control arms that bolt on, you can probably manage to mount them in close enough to factory mountings that it could possibly pass inspections. I have only installed these on street cars with fresh fabricated front sub frames but I have been doing a lot of thinking and I think this would work and still be legal if aftermarket ones are allowed.

Take all measurements and angles of all components while they are installed on the stock crossmember. You can mount your to be a more narrow track. width or a wider track width, or the ame as it is.

If you do this, be sure to set it all up just like the factory settings except you can add more positive castor if you want it. The factory top arm has an angled mounting for Anti-Dive for sudden brake application. Good thing for any car.

Ed

[Fisher]

Wow Foot brake that car works very well. You have to be making some good Hp to be doing that on the motor only. i am also building a 468 for my camaro, I am hoping for close to 700 Hp on the motor this time.

As or the above mentioned topic? I leave from a dead idle with my car on the motor. it was 2 tenths quicker than if i loaded up the converter. I have since put a glide with a brake in the car, this is going to be a whole new animal this year.