SST Newbie In Need Of Guidance

[Pony Pilot]

I’m a lifetime footbraker just now entering the world of Super Street. I purchased a #1 Stop and Biondo 4 stage timer in July and have been working to get to learn it since. The car is a small block Mustang with a 3 speed tranny and 5.14 gears. Vehicle weight is approximately 2,800 lbs. Wide-open performance in the heat is 6.40 to 6.42/105 to 107 MPH. Cool weather best is 6.25 @ 110 MPH at 75 degrees, 33% humidity.

After reading some of the posts on this forum, as well as any articles I could find on line, I’ve found that there appears to be a balance that needs to be found between RPM while on the stop and length of time on the stop. Too little RPM on the stop means too short a timer setting; too high an RPM means more time on the stop and more RPM creep while on the stop.

I live in the South, where there is only 1/8th mile tracks available. While there are several pro tree events, none allow throttle stops—which boggles my mind since stutter boxes and nitrous timers are allowed, but that’s a separate topic. Back the point, I’ve had to estimate quarter mile 10.90 times off of my eighth mile times. While many of the on-line sources state that a conversion factor of 1.56 was accurate, my own calculations came up with 1.57 being more accurate. Therefore my goal has been to get to 6.94 sec on the eighth, which will hopefully get me into the region of 10.9 on a quarter mile track.

The closest I’ve come to achieving this goal is a throttle stop RPM of 5,000 and a timer setting of 1.5 seconds (6.93 @ 105 MPH). From my reading, it seems the preferred timer settings are from 1.7 to 3.5 seconds, so I wonder if the RPM should be increased slightly so more time can be put in the timer? My only hesitation in doing this is the RPM is rock-solid at that timer setting. I varied the timer settings from 1.5 to 2.5 seconds to come up with a throttle stop ratio of 5.882. Does that sound reasonable? I have the stop coming on at 0.3 seconds. The 1-2 shift is done on timer at 0.5 seconds, and the 2-3 shift is done manually at 6,800 RPM.

I need to know from you guys that have been doing this for a while if I’m on the right track. I’m getting ready to dive into the deep end by entering Super Street at the NHRA Divisional race at Silver Dollar in two weeks, so if I’m screwing something up, it would be nice to know now!

Thanks for any guidance you all can provide.

[SuperCompDiv3]

If it works then nobody can tell you it is wrong. 5.88 is a very high ratio. You may have some adjustability problems. If it doesn't work out then I may suggest you set it up like I have below.

# 1 Timer comes on at .80

Stop RPM around 4300

Make one pass at 1.50 seconds, the next pass at 1.70 seconds to get some understanding of the ratio. Make sure you use the same lane, and the same day to do this. You must give the car at least one hour cool down time to make sure it is actual ET differences. Hot lapping will only confuse the numbers. Don't do a ratio by making a one second change in the timer, it won't stay linear. Only adjust it close to where the stop will actually be run.

You really are better off if you can get the ratio down to at least 3 to 1 ( .030 to .01 ). This way there is more adjustment range.

[HR9121]

First thing I can tell you is that there is no manual to make it work it will just be what works best for your car. I have run as little as 4 tenths in my timer( yes my car is slow) but it works for me. You have to find something that works for your set up but I agree with supercomp that you'll probably be better off getting your ratio down some and making sure its accurate.
My second concern is your rear gear ratio. Have you made a 1/4 mile pass to know what rpms you'll be turning. If you think that you might be turning too hard you can also go on the stop later that will help a little with down track rpms. I don't go on the stop till 1.50 this also helps with getting more accurate 60' times. I can tell you also that a 6.90 will put me real close to 10.90 but this varies from car to car. The faster cars will be much slower at the 1/8 to hit the 10.90 because they are killing so much at the low end of the track. Good luck and enjoy yourself its alot of fun.

[Ken MacNicol]

If you are 105-107 in the 1/8 you need to be about 7.15 to run 10.90, that is exactly the same MPH and ET my car runs.

[Pony Pilot]

Thanks to all three of you for your input. I plan to make full use of the test and tune Thursday night. I've already recorded throttle stop settings down to 4,800, so reducing it more should be too big a challenge. I will more than lkely try it first with my current settings, though I suspect Ken will be correct and I'll llikely go under by a bunch. But at least now I'll have a plan to recover quicker.

As far as the rear gear, this car has never been down a quarter mile. I recently geared down from a 5.43 to the 5.14s. In selecting gears, I really only had two choices: 5.14 or 4.86. I bought a copy of Quarter Jr years ago, and it predicted my eighth mile ET exactly (6,800), so thought it would also be as good as I could get for an idea of quuarter mile RPM (7,660). With the 4.86s, it would've brought my RPM way down--too far to work in the power band of my motor. I'm only working with a 383 (stroked Cleveland--not a Chevy), so I didn't think I'd have the torque needed to pull the 4.86s. That and since the tracks are eighth mile in my area, the 5.14s seemed the best compromise.

I hope you guys are right; that this will be fun. I've attended many national events and participated in several bracket finals, but never a divisional race. To be honest, I'm kind of sweating what to expect from the tech inspection. My chassis is certified, my safety gear is up to date. I don't have a clue how loud my car is decible-wise, and I pity the poor fool who wants to try and trace the wires under my dash! So any insight as to what to expect would be appreciated!

I'm not under any illusions here. If I can go to this race, figure out the routine, run a 10.90-something, not humiliate myself on the starting line, and not fill the engine diaper with parts, it will be a successful mission. Once I obtain a clue what I'm doing, I'll work on getting competitive for South Georgia and Gainesville next year.

[Bob Verwold]

As far as tech goes, if everything is up to date you'll have no problems !

The best part of div racing is the people that you'll meet (other than racing) and there is always a party some where in the pits at night......

Also, I'm about 7.00+ or - on 1/8 mile to end up 10.90

[nickh]

Converter? What size and stahl? Did not see anything on your converter but I did read your post without my cheaters! LOL

[Pony Pilot]

ATI MRT 8-inch and 5,700 stall

[Dennis424C]

The best advice I could give you is that the lees time you can spend on cruise the better off you will be. Remember your car will be the most consistent when you are WOT so keep that in mind when you are trying to find the right setup. Also good luck with the 3 speed trans that will make it a little more tough too.