Converter questions

[QDRHRSE]

Guys,

My truck is now running respectably. The only problem I'm having now is traction. My local track is a real POS and they only prep the track for special events. Traction is a big problem. I recently installed 4.10's and 2600 rpm converter. Even on 28 x 11.50 ET Streets we can't stall the converter without busting the tires loose. For the first time I actually tried to stall it up [my first nitrous pass as well] and I fried the tires all the way to the 1/8 mile mark, let off, got on it again, and then fried the tires some more all the down to the finish. It was a wild pass to say the least! The truck got very out of shape. Although it was my first nitrous pass, my friend made a couple before me without stalling it up. His 60 ft's were not stellar either. Anyway, it seems like a different truck when I use the converter. Does stalling it vs flashing it really make that big of a differece? I know at 2600 rpm the truck is really making a lot of tq but damn the difference was amazing.

[BigBobsL]

I run similar converter and 4:10's with built motor. You do not need to stall to max rpm to take advantage of a high stall converter. I generally get the best 60's with a flash by stalling at 1000-1500 rpm.

My best Reaction Times come with converter stalled 1500 and higher, but can only stall to max rpm at a veeeery well prepped track and with lots of legal ballast (spare and hard cover, lots of gas, tail gate, etc. When running light usually stall at 1500-2000 rpm depending upon track. Your truck will be different of course, but demonstrates concept that max rpm stall is not necessarily what you are looking for for best ET.

Flashing the converter lets the motor build momentum before it see the load and is sudden hydraulic lock up of the converter is more like popping clutch on a stick car with the motor accelerating. Downside, the time required to flash the converter to hydraulic lock-up can vary and also adds to reaction time. You can bump in a little to compensate, but varying length of bumps (run to run) and varying throttle response times to coverter lockup of the can make RT less predictable.

You can get more traction if you go with the M&H 14.5 x 30" tires, but this is rather expensive if you do it right and spend $800 for a pair of Bogarts to tuck in the fat tires.

Sorry if I am guilty of telling you how to build a watch, I do a lot of teaching in my day job.:o

Tom - Just noticed you are in CA, long commute to TALON; don't get to hang with them very often myself, but good group of guys.

[QDRHRSE]

Bob,

You're advice is very appreciated. My friend and I already discussed the 14" hoosiers and that's the way that I want to go but I will probably cheap out and buy Welds. Any idea how much the 30x14's are?

Also, when I first got my L, TALON was the first website that I found. I didn't know about NLOC or SOCALLOC. The TALON group has been great so I still hang out here. The Texas guys are very helpful and I have actually had a lot of good luck finding parts and what not through TALON as well.

:beer:

[RSVT]

which would be better w/3.73's the 2400 stall or 2600 stall?

[QDRHRSE]

I wish I could give you a good answer. It depends. If you have a fully built 10 sec truck I think you would do best with 3.55's, otherwise, 3.73's are a great all around gear. Too close to call that one. My truck is as built as it could be with a stock motor and ported Eaton. The only upgrades I could make now are a built motor and a real blower and/or more nitrous. All I can say is the truck was literally uncontrollable when I stalled up the converter and gave it a 75hp shot of nitrous. People were talking about one of my passes all night on Friday. I got wicked out of shape. I usually wouldn't lift off the throttle but the rear end really started to come around. If I could harness the power.......

[BigBobsL]

which would be better w/3.73's the 2400 stall or 2600 stall?


You will not see a significan difference and suspect you are talking about the same converter, seems different vendors may quote slightly different stall rpm for the same convertor. As I recall, PI offers their converters in 300-400 rpm steps, you can not predict stall any closer than that.

Further, torque curve is so flat that difference is negligable. I increased stall 400 rpm on same PI converter and saw little if any change in 60 ft, mostly more flash effect.

While it no doubt is fun to spray off the line, suggest using a controller to delay hit for a second or bring it in gradually over the first second. Try launching without purging, this will soften the hit and help traction.