This might be a little hard to estimate but I was wondering what 60 ft. times I should expect with my setup. I used a G-tech pro competition and it said I got 2.027 60's. Here we go

1972 chevelle 3600lbs with me in it.
3000 stall 350 turbo trans 3.73 posi.
355 with systemax II kit
camshaft .490/290* int .490/297* exhaust 107*centerline 112* lobe sep. 235* int 240* exh @50 10 to 1 comp.
750 vacuum secondary holley street dominator dual plane intake
1 5/8 headers with 2.5" exhaust and 40 series flowmasters.

I am running 275/50/15 bfg drag radials with 30 lbs of air in them. (I need to try with less air)


just wondering if this is super slow or about right for my combo.

Has anyone else used the g tech and is it very accurate?

Thanks

16-18 psi is all you need...I'd say 1.8 range

Thanks
I am going to the test and tune this weekend at Mid America raceway this weekend and want to beat by last year best of 13.8 @100 mph. Hoping these drag radials will do the trick.

Anyone have a ET and MPH estimate for me?

2 weeks ago I had my drag radials on 60ft times were 1.76 and up, this week with slicks on 60ft times were 1.76 and up. My best 60ft ever has come on drag radials 1.64 vs 1.66

The g-tech pro is a piece of c**p. I had one and it couldn't get within a eight tenths of a second on my buddies Camaro S/S Car. G-Tech said 11.38 @ 117, track timers said 10.40 @ 128. Likewise off on every car we put it on. Finally gave it away.

Clem,what was the 60 ft. on your 13.8 @100 mph run?

Clem, if you haven't been to MAR on racer appreciation day before be fore warned. Get there early and get right into the tech line, it never seems to get shorter as lots of folks will be there for chassis certification. Enjoy the free BBQ and maybe I'll see you there. This is the first one I won't be able to race at in 5 years...also the first one in that time it isn't supposed to rain! regards, Gary graemlins/thumbsup.gif

As fas as your 60 foots, try this formula:
optimum 60 foot = (.12 x 1/4 mile ET)+.17

It's pretty darn close in my experience.

Bob,

Put that ATI converter to work and hook that puppy up. smile.gif

If my old weak kneed little 'ole pump gas 383 SBC can pull off a 1.60, I know you can with that BBC power. ;)

Seriously though, send some video down and I'll try to help you get it to hook. It's hard to go rounds if the 60' isn't consistent.

If I can get my daughter(she runs the camera)to get a good video at the starting line,,I'll do it. Its all been TNT so far,the track is much better on race day, as tomorrow will be with the Heads Up shoot out boys in town. With a better track I'm hoping for high 1.6's at least, we'll see. On race day it is pretty consistent,never made it to a final yet,but 6th place in points last year aint too bad with a street car,,,wait,I made it to the final in the gamblers race last weekend.... :D Should be excellent air tomorrow too,,,dry and cool 66-33 ;)

Good luck tomorrow Bob. graemlins/thumbsup.gif

Thanks Jason graemlins/beers.gif

Clem, i'm going to say that the G-tech thingy is a little off. i'd bet with good traction you should be able to get high 1.70's or low 1.80's 60 fts. probably should be good for some low 13's in the 1/4mi, maybe high 12's. i'm not familiar with the Holley heads and cams so high 12's is giving them the benefit of the doubt.

Clem, A car with 100 MPH trap speeds isn't going to 60' better than probably 1.8 or 1.9. It is going to take more power to get better 60's. My son has a 71 Chevy that has a very healthy 481 in it right now and it does 1.6-60's and it runs 11.30's @ 116.9 MPH so don't be dissapointed with anything under a 2.10.

Your combo seems pretty well matched. I would say that 1.7s are possible and maybe better. Most of the time slicks are a no brainer as you can mash the petal and it will hook. Many times drag radials take more time and a little pratice to get the best performance. I would say 1.8s should be easy and 1.7s with some trial and error. At any rate you should beat the 2.0 times. Good luck.

Originally posted by DragRacer:
As fas as your 60 foots, try this formula:
optimum 60 foot = (.12 x 1/4 mile ET)+.17
It's pretty darn close in my experience.
Any formula for 1/8 mile? Your formula says I should have 1.81-1.82 60 foots with a guesstimated 13.73@99mph 1/4 mile et. My best 1/8 mile so far, which is also my fist time at the track, is an 8.80@79mph.

..that formula doesn't work for me..my 12.99 ET equals a 1.72 60 ft. and I did a 1.83 to run that ET and since my carb change,a 1.90 will get me the same ET (12.99)

:confused: maybe its the oddball gear in my combo..

LXS,

A good estimate for converting your 1/8th mile time to 1/4 ET is.... 1/8 ET * 1.57. In your case 8.80*1.57=13.82.

Chris,

The formula gives the optimum 60' for a given ET. Your gear 2.73 gear ratio definitely is not doing you any favors off the line.

Well I had a pretty good day at the test and tune on Saturday.

My new best 13.24 @ 99.55 mph and I managed to 60' at 1.83 with the drag radials. I was really hoping to get into the 12s but beggars can't be choosers. All of your advise seemed very close I appreciate it. Could not get the car to go over 100 MPH no matter what I tried. I tried going up with the jet size and advancing the timing a little. Went from 70 on jets to 72s. And 38* total to 40*. still 99.55 is all the mph it would run. The BFG drag radials did not slip at all if when I ran it up to about 1500 rpm and flash stalled it at the tree. I guess i just need more POWER! Very addicting.

Clem,nice job graemlins/thumbsup.gif
What was your 60 ft. on your 13.8 @100 mph pass?

I think it was in the 2.1 range. I was using street tires and could not keep from spinning unless I eased into it.

2.1 sounds about right..

a friend of mine is running a similar combo and just on regular every day street tires he was able to get down to a 2.00 60 ft time running 13.30's at 103+ mph........ this took some practice with feathering the throttle off the line and if he just plain blew the tires up then he would come out with 2.30's and 2.40's 60 ft times....... this was with 18 psi in some 255/60 15 tires........

those drag radials should be optimized for traction by doing little burn outs and checking the contact area on the ground......start out with like 25 psi do a small burn out about 1 foot long and check. if its still dark in the middle and lightens out in color to the edge then lower the psi and do the small burn out again til you have the widest and even color contact patch on your burn out......this can be done before you get to the race track so you dont have to guess what psi you should be running

this way you can concentrate on the burn out system that suits you best.....you should be able to just run thru the water box and run the car thru first gear to 5000 rpms and shift into second gear and as soon as you hit 5000 rpms let off the brake and run it up to the staging beams........make sure you come out of the box under throttle and brake just before the lights........and stage the car.......after doing this several times you should get the feel for how hard you can hit the gas ........i dont think those tires will hold a full throttle launch but you should be able to get the feel for when they are getting close to breaking loose.

you should see some 1.80 60 ft times out of them

Any ideas on why I cannot get the crate over 100mph. It seems everyone else is running 100+ with the same or longer ET than I am. Possible fuel delivery problem or just not enough HP?

Any suggestions would be appreciated.

Originally posted by DragRacer:
LXS,

A good estimate for converting your 1/8th mile time to 1/4 ET is.... 1/8 ET * 1.57. In your case 8.80*1.57=13.82.

Chris,

The formula gives the optimum 60' for a given ET. Your gear 2.73 gear ratio definitely is not doing you any favors off the line. I don't have 2.73s, I've got 4.11s. Or were you talking to someone else?... My best 60ft on the 1/8 mile was a 2.02. What does the 1.57 stand for? Is that giving my the benefit of the doubt of having a really good 60ft time? thanks for the help. graemlins/thumbsup.gif

Originally posted by clem72:
Any ideas on why I cannot get the crate over 100mph. It seems everyone else is running 100+ with the same or longer ET than I am. Possible fuel delivery problem or just not enough HP?

Any suggestions would be appreciated. you may just have to do some fine tunning you would be very surprise to how much mph you can get out of jetting, timming curve, total timming, and the rate of secondary opening on a vacuum secondary carb........even on my own holley 750 vacuum secondary carb just a spring change gave me 2 mph trap speed going from the stock spring to the tall yellow spring......so i'm sure with some tunning you can find your mph somewhere.........i have gone to the track many times with fresh motors and by the end of the day i have drop up to a sec in my e.t.'s (traction ordeals) and found of upwards of 5 mph just in tunning the carb and timming and so forth.......

so im sure its there you just have to tune it........

My old combo must have been really messed up. None of these formulas work for it.

60' 2.118
1/8 8.684@84.469
1/4 13.325@105.681

Hopefully the 454 will get me into the 12's

To anybody, If you come out of the burnout box at 5000 RPM in second gear and HOOK you are going to send your transmission into sensory overload and break the sprag. My son has broken three so far. The same will happen with spinning on street tires and hooking up suddenly. Now he has started listening an going 1-2-3 and coming out off the gas as the tires start to catch up and bite. Guess he got tired of changing trannies. I'm told that only a light spin without water is the best for BFG Drag Radials.

The 60' formula assumes three (3) things:

1.) There is NO tire spin.
2.) Your combination has the proper gearing and converter stall speed.
3.) You leave under full power.

Simply put, the formula tell what the OPTIMUM 60' time would be for a given ET.

Burn outs should be started with the shifter in 2nd.
When it hits 2nd wait for the rpm to climb a bit and shift to drive.When a good haze starts to emit from the tires (not pro stockish)
lift of the break to come out of the water.Lift off the gas smoothly before it hooks.

NO dry hop,stage.

One thing for sure, don't end it in second.