Launching RPM with a 3400 stall conveter

[JonnyG2132]

I normally launch around 1200-1500 with my precision 3400 converter. I usually cut 1.70 - 1.75 60' on Nitto NTO5 street tires, which I think it pretty good for street tires. Im going to be going with some drag radials on 17 inch rims soon, and hopefully start getting lower 1.6 60'. Should I change my technique and bring the RPMs higher at the line or keep them lower and flash the converter more? I see some go from idle, some from where I launch, and some from 2000 - 3000 rpms. I didnt know if it depended on the converter stall or not?

Thanks
Jon

[ULTRA Z]

This is not a question I feel can be honestly answered. there is to many unknown varibles. Track condition, tires/tire prep, susp, all the way down to the actual hp and tq curve your motor makes. Got to the track and do a burnout you feel is a nuff to get the tires sticky and try and repeat this so that doesnt change from run to run. normally the more you flash a converter the more shock and the quicker it leaves but the more prone to wheel spin it is also. its a if it hooks its faster kind of thing. I would start by stalling it high and every pass drop 500RPMs till it starts to want to spin the tires then I would look into lowering the air pressure some if there is room to do so and if not try a longer burnout and get a friend to make sure you are on some good rubber at the line. If it spins again then thats all you can do with that tire and stall it a touch higher and there you go.....

remember this launch RPM you just found is for your car/engine/tire combo on that track on that day. If they prep the track more and the weather is better then you may can stall it lower and leave harder and not spin. also if they don't prep it as good and the weather is putting moisture on the track then you will spin when you leave from the founded RPM and you will need to stall higher that day. It won't take long before you get a good feel and can guessitmate this in one or three trys

Best Luck to you.

[JonnyG2132]

This is not a question I feel can be honestly answered. there is to many unknown varibles. Track condition, tires/tire prep, susp, all the way down to the actual hp and tq curve your motor makes. Got to the track and do a burnout you feel is a nuff to get the tires sticky and try and repeat this so that doesnt change from run to run. normally the more you flash a converter the more shock and the quicker it leaves but the more prone to wheel spin it is also. its a if it hooks its faster kind of thing. I would start by stalling it high and every pass drop 500RPMs till it starts to want to spin the tires then I would look into lowering the air pressure some if there is room to do so and if not try a longer burnout and get a friend to make sure you are on some good rubber at the line. If it spins again then thats all you can do with that tire and stall it a touch higher and there you go.....

remember this launch RPM you just found is for your car/engine/tire combo on that track on that day. If they prep the track more and the weather is better then you may can stall it lower and leave harder and not spin. also if they don't prep it as good and the weather is putting moisture on the track then you will spin when you leave from the founded RPM and you will need to stall higher that day. It won't take long before you get a good feel and can guessitmate this in one or three trys

Best Luck to you.

Thank you for that information. Def a lot to consider. What I have bolded is key to answering my question! So I guess I couldnt have asked the question differently. Mods and HP/Tq are below in my signature

Thanks again
Jon

[427g8gt]

if what you are doing is working out stick too it.

[ULTRA Z]

LOL well I guess over kill is better than half a answer sorry but glad I got you a answer. I'll be getting after it also here in another week or so. 26x11.5x17 MT ET Streets on the way and a NW 102TB on the way also. You got a nice list of mods there.

[JonnyG2132]

if what you are doing is working out stick too it.

Ya I agree with you. I just didn't know if I should lower the RPMs or raise them at the line with stickier tires

Thanks

[JonnyG2132]

LOL well I guess over kill is better than half a answer sorry but glad I got you a answer. I'll be getting after it also here in another week or so. 26x11.5x17 MT ET Streets on the way and a NW 102TB on the way also. You got a nice list of mods there.

I appreciate you taking the time to give me all that info. I was looking at those. I want more of a taller tire though. Thanks. There is always more to add to the list lol

[locrzn#92]

I would not run that short of tire with the 3.45's with your setup, your are right to go with a taller tire. You mph will be higher with the taller tire and the shorter tire will just be harder to hook. How tall are your NT05's? You probably have the best street tire 60' times. I was only averaging mid 1.70's with my Dr's, however I do have stock converter, I have had a 1.66 Nitto Nt05r's and 1.63 on my Mickey Thompsons. You should be in the low to mid 1.60's with dr's. I think you'll see better 60' times with launches in the 1500-2000 rpm range. Converters are kinda like turbos, they spool up before they launch and sometimes with a converter you can load it too much and it won't launch as well as it would at a lower rpm, turbos spool with exhaust gasses and converters with fluid. Its gonna be different with a dr or a slick, you'll figure it out.

[JonnyG2132]

I would not run that short of tire with the 3.45's with your setup, your are right to go with a taller tire. You mph will be higher with the taller tire and the shorter tire will just be harder to hook. How tall are your NT05's? You probably have the best street tire 60' times. I was only averaging mid 1.70's with my Dr's, however I do have stock converter, I have had a 1.66 Nitto Nt05r's and 1.63 on my Mickey Thompsons. You should be in the low to mid 1.60's with dr's. I think you'll see better 60' times with launches in the 1500-2000 rpm range. Converters are kinda like turbos, they spool up before they launch and sometimes with a converter you can load it too much and it won't launch as well as it would at a lower rpm, turbos spool with exhaust gasses and converters with fluid. Its gonna be different with a dr or a slick, you'll figure it out.

Thank you for all of that info. My NTO5s are 26.5 inch street tires. I am actually in the process of ordering 28 inch drag radials, so we are on the same page. I am def hoping for a 60' like you are getting. I would assume I would with a stickier tire. I have never launched over 1500 but we will see. My idle is at 980-1000, so I was going to try idle all the way up to 2000 and see what happens.

Thanks
Jon

[OLD_GOAT]

I agree with UltraZ, there are too many variables in order to give an absolute answer to.

After Patrick G did the work on my car (headers, tune, CAI, nitto nto5r drag radials on 17" rims, and a 3200 stall), I was stalling to about 2000 rpms, then launching. One time at the track, they happened to give me a pro light, and instead of stalling to 2000, I just launched. This was the first time I ever had this happen, and this is how I got my personal best time, to this point. Since that time, I always launched off idle. It only made <.1 time difference, but if you run a 12.03, that's good enough to get you into the 11's.

Here's a video of that run.

http://www.youtube.com/watch?v=ltVqO...5&feature=plcp