Oddly enough, I can't find any topics on this, not even google.

I have a 2800 - 3200 stall converter in my car. What is the proper way to launch with a high stall converter? I've tried a few goofing around launches, and noticed that with a good amount of throttle, the RPMs will get to around the 2400 range, but the car feels weak on takeoff. With a generous amount of throttle, Maybe around 85% but not that last bit of oomph (For fear of breaking the 10 bolt), It can bring the RPMs to about 2700 and when the break is released, you can feel the car rear back. I have yet to footbrake at WOT.

Just curious as to what the proper procedure is.

 

Whatever works best for you. Some take off just above idle to flash the converter, others stall it up to just before the tires start to spin.

 

I've always brake stalled it as high as I could and then mashed it from there. That gave my best 60s. Alot of racers say to bring rpms just above idle and flash it. That never worked well for my bolt on L98 nor my 383 HSR motor.

You should not break that 10 bolt with your motor. Bring it to 100% on launch. Brake stall as high as you can and then mash it! Try that and then try brake stall to like 1200 rpm and then when ready to launch, mash it from there. See which one gives the best 60 foot for your setup

 

Never been to the dyno, but this TPI has a few bolt ons, free mods and headerback exhaust plus the ECM is chipped. I'm estimating power around 270/310. And I have nitto 275/60 drag radials. The rearend is a pegleg. I've never opened it up but I did the driveshaft turn thing and if I did it right it should be a 3.23.

Then again, I have heard of people putting stock 10 bolts behind 500+HP motors that lasted quite awhile.

Oh and the struts are aftermarket. I know sensatrac aren't the best, but they're decent. I also have boxed LCA's so I get no wheelhop.

 

I beat the hell out of my 10 bolt with a 400whp 11 second 383 motor and it held on drag slicks. 1.5's 60 foot. I even sprayed it a dozen times, with 2 right off the line to a 1.41-1.45 60 foot. Held fine. Put that rear behind my 650-700whp turbo motor and it held fine. Eventually had a worm gear chip and start making noise so i swapped it out for a 2.73 rear 10 bolt. No problems yet on that and i've been in the 9's with that rear although the 60 foots arent as strong as they used to be. 1.6's which is not far off a bolt on L98 60 foot time. The power and torque going thru it just after the 60 foot however has to count for something.

Some get lucky, some dont. I did break a spyder gear in my factor 9 bolt with a bolt on L98 and 2800 stall. Can happen but that bolt on L98 never hurt that 10 bolt. That 10 bolt wasnt hurt by the 383 and only the turbo motor eventually chipped a tooth on a worm gear from spinning tire and locking up the diff on the street.

 

You have a 305 with 3.23 gears so you aren't going to get neck braking launches.

You are most likely over-estimating the power of your motor.

My old cammed 305 TPI was estimated about 250hp
http://www.youtube.com/watch?v=lLBfKEsgFmo

 

[quote=Orr89RocZ;4624081]I beat the hell out of my 10 bolt with a 400whp 11 second 383 motor and it held on drag slicks. 1.5's 60 foot. I even sprayed it a dozen times, with 2 right off the line to a 1.41-1.45 60 foot. Held fine. Put that rear behind my 650-700whp turbo motor and it held fine.[quote]

Really? What mods to rear?

 

Bone stock rears. One was painted, one is all rusty. These are 4th gen 99-02 rears with zexen torsen diffs however. 28 spline axles I believe so they may be stronger than the earlier thirdgen 10 bolts that were 26 spline and feature auburns or other clutch type posi's. Yours being open leg wont have to worry about wearing out the clutches.

10 bolts usually brake gear teeth off pinion or bull gear. Some split the case in half. I really dont think your 305 will stress that rear that much.

 

I recently asked Yank torque converters that very question. They said with my setup to break torque it as high as I can at the starting line. I have been going off idle and will try the break torque method the next time out.

 

All I know about my rear for sure is that it is NOT the original rear. I managed to get in contact with the second owner of the car (I'm the fifth), and he said that one day at the strip he threw the pinion gear out and replaced it with a 3.73 rear with girdle cover (However, I think the shop that did the install flimflammed him because he was led to believe it was an 8.5 10 bolt out of a grand national). However, that is obviously not what is in it now and the cover is just a fancy chrome one. The 4th owner I bought it from said he did nothing to the rear so the 3rd owner had to have done something to it. Possibly it is the same rear the 2nd owner replaced and the 3rd was just a dumbass and felt like having something SHINY and replaced the cover. I think he was selling performance parts off the car for cash because alot of the stuff the 2nd owner put in it including the MSD 6AL was long gone. There was only a 2 year time period between me and the 2nd owner.

What exactly type of rear it is (I can tell It's not an 8.5 because of the oval shaped pumpkin) is a mystery currently but I know it is not the factory unit.

 

Oh and another thing the second owner told me, was that the rear was LSD but in order to get it to lock you had to hit the gas, then just as the car started to move slam on the brakes. Which didn't make a hill of sense to me

 

unless he was talking about a gov-lock style posi. They require some wheel spin to lock.

Can you take a pic of the rearend?

 

Well there are a few ways to launch a converter car! It will take a few passes at the track to get your 60' times down,some converters like to be stalled up a little whereas some like to just be flashed.

I have had SLP,TCI,ART CARR and brittans converters and they all liked to be flashed...every bolt on(as if there were that many back then) '91 5.7 w/2600 stall on comp TAs (old style)1.72 60'.....yes i had plenty 88-92 f-bodies

 

This is a good point I forgot to mention is that not all converters are the same. 2800 stall converter from Company A may not act the same as Company B's 2800. Different stall ratios can impact how much power is transfered to the tires and how violently it hits. Converters that hit tires hard may like flashing but softer converters may like rpm.

 

Track run was horrible. Not the fact that I pulled a crappy timne, but the fact I never got to run!

I pulled in and just chilled in the spectators box for 30 mins observing how everything was done since it was my first run at the track. All of a sudden, they called the 7 minute warning so I was like oh crap and ran to my car. My friend who drives a 99 honda prelude (Thinks he can beat me and was the reason I was there), pulled up alongside in the staging lanes. We just chilled there for 5 minutes like "uuuh is someone gonna come write a number on my windshield or what?". Then the guy said it was over and they weren't doing anymore runs.

I did talk to the owner though and got a free pass for next week since I paid the $15 admission fee.

However, I just couldn't take the suspense any longer. I just got back from doing two WOT launches on a backroad. When stalled at part throttle then flash to WOT, the launch felt LAAAAAAAME. However, when I mashed it to the floor and then released the brake, the whole front end picked up, so this converter def likes to be stalled high. The rearend held up just fine, too!

 

Loading up the converter can help because you'll launch closer to your peak torque however there are other things to consider. You'll never foot brake launch to the converter's true stall speed except for very low stall converters (under 2000 rpm). You need a transbrake to launch at the full stall.

When you come up on the converter with a carb, you've given it part of the accelerator pump shot. When you finally go to WOT, there's a good chance you'll get a lean bog because there isn't enough pump shot left over. EFI is a little different and shouldn't be affected the same way. To give the carb the full pump shot, different pump cams can be used or launch from just off an idle.

Don't believe anything about loading up the driveline. I use a transbrake and with the 2 step turned off, my converter stalls at 6200 rpm. The transbrake locks the tranny so no power goes out. The driveline has no preload. When the transbrake releases, all the power hits the driveline at once.

 

if you tighten up on squirter adjustment at pump arm that should theoretically give you a larger window of pump squirt at a higher rpm?

 

But you still need some pump squirt just off idle or the engine will still lean bog and die as soon as the butterflies start to open.

If you look at the selection of pump cams to choose from, you can see many different profiles. Some give a huge shot right at the beginning, others have a more moderate curve. Like any other tuning device, what works well on one engine may not work for another. They're tuning aids.