I have a stock 68 390 AMX 4 speed and was wondering how you Pure Stock guys get good times with a stick? I only had the car to the track once and the best I got out of it was a 14.72 @ 93 w/a 2.23 60'. I only got 3 passes so I didn't get to experiment much. Is it better to "haze" the tires a little and ease into the throttle as they grip or slip the clutch and nail it when the pedal is all the way up? The car has 3.15 gears and a T10 4 speed. Even with the mild gears traction is an issue.
I'm certainly no expert, but.... I've only had one 4spd car at the Pure Stock Drags, I have driven a friends stick car also, and I can tell you for sure that they're all different as far as what the best launch technique will be. Many factor's, tire size and type(radial vs.bias-ply), rear gear ratio, which trans you have and what it has for 1st gear ratio,weight of the car, how is the advance in the distributor coming in? I can tell you that your mild rear gear is not helping you. Most of the guy's who run in these races will probably be able to tell you that they improved their 60ft times,and almost solved wheel spin problems when they switched to a lower rear gear(3.73,3.90,4.10,etc.) Sorry if this didn't answer your question, just a little worthless input :grin: If you aren't looking to make changes to your car,as far as changing the gear ratio, then probably the best thing to do would be to get some more track time,and experiment with different launch techniques just as you described, and find out what your car likes best. Good luck :TU: Tom
All the gear it can handle........ Neither one of those for me. A quick, controlled clutch engagement, quick but not a dump, simultaneous throttle stab, from an RPM that keeps the tires stuck.....barely. And gear the living stink out of the car.......... My two cents.
Second gear is for PANZIES!!!! But you must consider, that last bit of *advice* comes from Mr. "1-3 shift" himself! :laugh: ------------------------- Hillbilly Racing Team "Tired of AutoZone's limited selection? Try the Pottery Barn!"
Rob, I may have to remove myself from the Hillbilly Racing Team if you admit to shopping at both Auto Zone AND The Pottery Barn! Brian, Is there still room on 'Team Stefina' and do I have to wear a thong like Dave? ou:
I don't drive a stick, so you can toss my advice in the trash. But I just wanted to reinforce what the others are saying about going to lower gears (higher numerically). I know it seems counterintuitive -- you might think the lower gears will give you too much rear-wheel torque and cause the tires to spin even more. But the opposite happens -- automatic or stick. There's two reasons. First, the lower gears make the weight transfer quicker, meaning there's less chance the tires will even start to spin. Second, once they start to spin, the lower gears both prevent them from spinning too fast and also help the car catch up to the tires quicker. One place you'll notice the effect of lower gears producing less wheel spin is in the burn-out box. You'll find that to achieve the same wheel speed and smoke factor, you'll have to do your burn-out in 2nd or 3rd gear instead of first. Don't forget the traction aids. A working posi and a little extra weight or preload on the right side will work wonders. Of course, once you get traction you'll now have to tune that bog out of your carb -- you know, that bog your present wheelspin is covering up. :Smarty:
i agree , spinning the tires and trying to drive into it is not a good thing , i'm still trying to figure mine out , but wheelspin isn't a big concern in a slug of a mopar
Tommygoat it is very simple. Buy a bunch of good Canadian beer, take said beer and ply the Nueclear Shifting Machine (Jimmy Johnson) with it. He will drive your car very well. The other option and likely cheaper is: Take a higher than you would expect launch rpm, slid the clutch feeling the bite in the tires and feed it in as quickly as it will hold, at the same time add more gas smoothly/quickly. Short gears certianly help here. From run to run it will change how far the clutch slide will take. At times I would say I am 20 feet out. I am running low 2.0's in a 4000+ lb Judge and 1.95's in a '71 T/A with this combo. We shaved .2 off another RAIV Goat this fall with this method. I have several T-10 equiped cars and they have a 2.23 first gear which is similar to the 2.20 first in my M21 cars mentioned above. Gear is a must with these trans'. The problem you will have is similar to the SC/Rambler I have, no rev's out of the early AMC's. A combo of stock .050 duration of 196/196, poor flowing heads, horrible exhaust manifolds and small carb. The best gears to survive the small tire no rev issue at the end of the track are 3.54 or 3.73. Your car is light so it will get moving fairly easily with these middle sized gears while still having enough to keep you in the power at the end of the track. Good luck and you can add my info. to the pile above as just general suggestions for you to apply and find the balance for you. Mark
Practice All good info above! But, to be fair to yourself and the car you need to practice as much as possible. The guys that are good have been doing it a long time. Make sure that the clutch is adjusted properly. I think centerforce wants the clutch to have .030 clearance from the pressure plate to the disc and .030 to the flywheel. Look at the instructions closely. If it means that the starter has to come off so you can take a measurement than I would recommend it. Jim
Thanks for all the replies! I have the 2.64 low gear wide ratio T10 so it's not as bad as the cose ratio boxes. I have a set of 3.54's I'm going to try. This will give me the equivalent 1st gear ratio of about a 4.11 rear with a 2.23 low trans. I agree the small AMC cam/carb and log exhausts make for a low RPM torquer. And the single snorkle air cleaner doesn't help either. Going past 5K is a wasted effort. I only turned 4000RPM in 4th with the 3.15's so the 3.54's should give an extra 5-600RPM at the traps. I'd like to get into the high 13's with some tuning & practice. Mark,how much total timing do you run in your SC? I have to use a pump/race fuel mix to run over about 32 total. Sunoco 94 works fine under that.
get some 4.11's This is what ive done in different 4spd cars.Do a decent burnout,stage 1st so you can raise your rpm to the point where the tires won't break lose and hold that rpm,leave on the last yellow and ride the clutch while you add the gas and release the clutch{about 20 feet} then nail it and make sure you don't over-rev it.Ive also heard you should dump the clutch,let it stumble,then nail it,but thats never worked for me.This is a good topic lets hear from brian,casey,dave,tim,jim,tom,maybe i can learn something new.
Launching a no torque high hp small block is a real treat. Year before last, I had it pegged pretty well and had regular 2.0 60 footers except at Norwalk where I got consistent sub 2 second 60 footers and even one 1.90. I launched at 3000 with a soft clutch release and quick, but smooth accelerator at Stanton and Martin, but 4500 plus at Norwalk and dumped it. Car really liked that and jumped right off the line. This was with a very small cam (much less than the factory cam) and the original wide ratio trans. Car ran high 13's at 100 regularly and best was a 13.70 at Atlanta. It was a sitting duck at the 1000 foot mark, though, with no top end (nothing over 5500 RPM). I totally lost the ability to launch it this year, though. Nothing worked and 60 footers were all in the 2.1 to 2.3 range whether I launched easy and slid the clutch a little, bogged it, or banzai launched and spun halfway through first gear. The change to the cam timing right before Stanton (retarded), and the close ratio trans change this year combined for an impossible situation. There was no low end torque, but lots of high end hp. Soft launches (2000 RPM, soft clutch release) resulted in 14.1's at 98 MPH. Banzai's fell to 2.30's , but the MPH went up to 102+, but et's fell wat off. Even tried one launch on just the 2 barrel with the secondary air valve really tight. Still around 2.20 60 footer, Frustrating to say the least. Not sure where it's going this year, other than changing back to the wide ratio, going to leave it as it is and try different launch techniques. Engine really needs to go on a dyno to dial it in right. May even try the original 3.91 axle and stop beating on it. Hopefully will have the tripower 66 ready for the mid and late summer races. That'll be a lot of fun. That has a ST10 4 speed with a 4.10 rear. Those early 400 engines have the best of both worlds with great torque and mid range as well as high end hp.
When I was running my 4 speed 455 Buick I would hold the rpm at 1800 slowly release the clutch, slowly apply throttle, then when the car started to move I could release the clutch and plant the throttle. I drove a 71 442 using this technique. There is no one launch technique that will work for all cars. Each brand, engine size, suspension type and gear ratio will be different. What works for me may not work for you. You will need to experiement with your combination to find the best technique for you. I went from 3.31 to 3.73 gears and the car was easier and more consistent to launch .
You do have a nice combo to get moving with the wide box. As to timing every motor has its own personality and we are starting a new build up to ps the car. I always run a combo of race and pump gas in all my high compression motors so running as much timing as the motor prefers is never an issue. You should be able to run a bunch more than 32 degrees with your mixed gas. That will help your luanch torque also. Mix the gas as heavy with race gas as it takes. AMC's are said to not be to sensitive to timing/compression so I can not see how you would need more than 50/50 mix of 110 and pump gas. I run that combo in most of the cars. Remember to much race gas actually can hamper power so only run as much as needed. High 13's should not be an issue for you once you are dialed in. Mark
I always thought that the proper launch technique was to plant the right foot until the motor starts to slow down ou: And then side step the clutch pedel :3gears: :3gears: Mike
funny thing about that is over here in the southern tip of the appalachians they still call us rednecks. i drive an auto. guess i'm a candy. sorry :grin:
Dump the clutch at Norwalk and go, 14.26, Slowly dump the clutch at Stanton and spin, 14.4something. With Goodyear redline F70-14s for almost 9 yrs, I think this year.
I'm still trying to adapt to my close-ratio Super T-10. I was liking the A-833 OD 3.00 first gear, but I had to upgrade to the T-10 since the late model A-833 OD boxes aren't known for strength. I like Brian Stefina's advice. Give that a try. I see your in OHIO. Have you considered the UMTR?? Try www.umtrdragrace.com
