1/8 mile gear selections

[dirttracker]

New to dragracing been a dirtracer 40 years would like advice on gear for my s15 gmc.Has a 406 small block edelbrock performer aluminum heads stock out of box,12.5kbpistons,550liftsolidlifter camshaft,victor jr intake,willys 750gas carb,msd cranktrigger ignition with 7 al box,powergide with 8inch bte 4500 stall converter with trans brake,narrowed strange rearend with 33 spline axles,29/11.5w 07 compound hoosier slicks with 97 inch rollout,truck weighs 3050 lbs,has 12 point cage,10 gal cell mounted back of bed along side the battery,I can't give hp#s not a dynoed motor just a mild 406,I shift it at 6400,I tried a 456 went 7.32 @98mph with 1.70 60 ft time in 1/8 mile ,went through lites at 5400,would like some input on what others think about gearing,all motor NO NOS,Thanks appreciate any comments.

[BracketNova]

I have 4.88s with alot of similaraties to your setup. I believe I'm at 5800/5900 in the eigth.

[Bruce69Camaro]

Here's a formula for you to use.

Maybe this will help you out?

Tire Diameter x RPM / (336 x mph) = Gear Ratio

IE: 29 x 6400 / (336 x 113) = 4.89

Bruce

[mytmouz]

I ran 5:13's with a similar combo on that size tire on motor...

[wikd69]

New to dragracing been a dirtracer 40 years would like advice on gear for my s15 gmc.Has a 406 small block edelbrock performer aluminum heads stock out of box,12.5kbpistons,550liftsolidlifter camshaft,victor jr intake,willys 750gas carb,msd cranktrigger ignition with 7 al box,powergide with 8inch bte 4500 stall converter with trans brake,narrowed strange rearend with 33 spline axles,29/11.5w 07 compound hoosier slicks with 97 inch rollout,truck weighs 3050 lbs,has 12 point cage,10 gal cell mounted back of bed along side the battery,I can't give hp#s not a dynoed motor just a mild 406,I shift it at 6400,I tried a 456 went 7.32 @98mph with 1.70 60 ft time in 1/8 mile ,went through lites at 5400,would like some input on what others think about gearing,all motor NO NOS,Thanks appreciate any comments.

This is what I used to calculate RPM & gear ratios.

http://www.markwilliams.com/calculators.aspx

[dirttracker]

Appreciate the come back I believe you answered my question.I will build a set 4.88 and give it try and keep you posted. THANKS.

[dirttracker]

I put a 5.29 gear in it and ran 7.02 at 98mph with a 1.58 60 still only turned 6000 out the lights. I'm going to put some new slicks on this week and I'm hoping to get in the 6's.Thanks again for the input.

[Speedster]

we have a real simular set up except 31.0x12x15w tires launch on the trans brake 4000rpm. 4.88 spool pg trans.
60ft 1.718
330 4.959
1/8th 7.717
mph 89.32
1000 10.091
1/4 12.092
mph 112.59

i hope that helps

[dirttracker]

I went to denton tx. last night and ran a 6.9621,/1.5374 60 ft./4.4591 330 ft./ 97.61 mph./with a .1740 reaction time please don't laugh thats my best reaction time so far.Thats our fastest run yet. Olaho oregon is a beautiful place we lived in Eugene for 14 years.I raced dirt modifieds at willamette speedway in lebanon and at cottage grove,coosbay ,medford,up in washington at skagit speedway,as well as down in california.I was a decent dirt racer but I'm finding drag racing very challenging and that tree is a real hummer.Thanks for the info,I need all the advice I can get.You have a really nice ride and fast too.

[Speedster]

I'm a recent switch back to drag racing too! We started racing stock cars at portland speedway in the late 80's early 90's and some modifieds at south sound and in 98 we switched to dirt track racing and won 8 track championship 5 in a dirt street stock and 3 in a open wheel midget and ran most of those tracks you said. My son started in a camaro when he was 12 and we did that for 3 years and i got tired of all the work and money and sold everything to do with roundy round and bought a drag car and man everything has changed a bunch over the years but we are getting the swing of it again and have made all the way to the semi's once this year and my son is starting to chop the tree pretty good. he is living around .020 ave light and has a best of .002 this year. and number #1 qualifier once this year also. we started the year running 13.00 and our best this year is now 12.09 @ 112.59mph.

[dirttracker]

Thats kinda wild our backgrounds being about the same.I enjoy this aspect of racing at my age [58] because it is less work, I can't say I don't miss going in circles but I also don't miss the work involved in going in circles.I have only went to testntunes so far but tomorrow I'm going to go try out what I've learned so far, they are having some index races and I'm gonna run the 7.00 index class. I remember my first dirt race I did'nt win it either in fact it took most of the year before I won my first heat race .It sounds like your son is a heck of a driver and thats awesome.We don't have but a couple of quarter mile tracks left around here and they run 1/8 mile most of the time only run the 1/4 mile a couple times I guessa year.Do you run the same gear in the 1/8 mile as the 1/4.I wish you guys lots of success sounds like your going in the right direction.I'll let you know how I fare tomorrow night.Thanks for the come back.

[Speedster]

yeah we just run the same gear. im 45 on sunday and thats alot of the reason i quit circle track racing too.
i like to sit inside and play on the computer more then thrash on a car every night for hours. now i put in a couple hours a week and race when we feel like it and are having a good time. no stress. lol

[BracketNova]

......with a .1740 reaction time please don't laugh thats my best reaction time so far.

I'm not trying to be an A$$, I believe you said you were new to drag racing. Anywhoo - are you whacking the throttle when you see the green light? If your not using a delay box it you need to leave on or shortly after the last yellow. With your car probably shortly after.

My best reaction foot braking was .0001 in a reaction time contest...won 300 bucks for one pass =)

[dirttracker]

I know what your saying speedster I had 2 or 3 jobs most of my life and 1 of them has been circletrack racing,but you know I'm enjoying this new challenge........spaz109 thanks for the advice I appreciate the come back and I'll try it.

[dirttracker]

Well I went and tried to win my first dragrace and went 7.03 the first pass,7.10 the second pass,then the pass that counted I went 6.97 and broke out running in the 7.00 index class and to top it off I did a heck of a job I redlighted by .0085 on on pro tree.lol.Well I've requested help to make my ride faster and you guys came through my truck is pretty quick and consistent heres my next request how you gonna help a old dirttracker get more consistent on the lights,I know practice would help but come on guys I'm old and looking for magic!Appreciated the come backs and help,I'm having a blast and looking forward to getter better.Good luck to you all.