doc

I recently bought and installed an Art Carr 2400 stall torque converter along with a new cam and AFR heads.

My problem is that my brakes are too weak to hold the car still at the starting line at the dragstrip if I try to stall the converter above 1500rpm. I'm limited to 1500 rpm and I think this is why I am not going faster than 13.39sec. I should be able to stall out at around 2000 to 2400 rpm.

Short of spending $1200 on a Baer front brake upgrade kit, what about a line lock system.
I dont know anything about a line lock. Can someone please help me with this?

What else can I do about my stall speed at the dragstrip?


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'87 L98 TPI IROCZ, AFR190 heads, 3.70 gears, ZZ9 cam, 2400 Art Carr TC, SLP 1 3/4" headers, SLP cat-back, no cat, no AC, no MAF screens, Accel manifold base & SuperRam, Edelbrock double roller timing chain, MSD ext coil & distributor, trans cooler, 52mm TB with airfoil, TB coolant bypass, AFPR(48psi), K&N filters, Hotchkis lowering springs, Car-Pro custom chip, Lay Ind. ram air kit, 265/45R16 Kumho V700 tires.
'90 Eagle Talon AWD, no rust thru 9 winters
'99 Camaro SS, red, 6-spd, T-tops, Mcleod clutch, Pro 5.0 shifter, MAF processor, Direct Flow airlid, K&N filter.
313.7Hp & 320.6ft-lbf, 13.55sec @ 105.1mph

GregWestphal

iTrader: (1)

This won't answer your original question, but you don't need a line-lock unless you want to hold the car still for burnouts, and even then it isn't necessary. What you're calling the stall speed isn't the true stall speed of the converter. You're sort-of measuring the foot-brake stall speed, but the one you're really interested in is the flash stall speed, the rpm at which the car starts moving when launching. This is comparable to the engine speed at which point a clutch is let out quickly or dumped. The higher engine speed this is done at, the better launch you'll get (assuming you still have traction), improving 60-foot and 1/4-mile times.

I have a 2200 stall converter (more like 2400 though) in my IROC and I just pull up to the line and bring the revs up to about 1000 to 1200 rpm, depending on how good the traction is. Any higher, and I usually just spin my tires really good coming off the line. With a higher-stall converter, you let the converter do the work in stalling at a higher engine speed. The main reason to bring the revs up a little is to make sure you have the drivetrain pre-loaded and all of the slack (in the U-joints and gear backlash) is taken up so you don't shock everything (bad for parts and traction). If you have any sort of scan tool, watch your rpm vs. mph and see what the highest rpm your engine reaches before you start moving. That's the converter's actual stall speed. HTH...

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Greg Westphal
'87 IROC 305TPI/A4

rich1034

A line lock is just a solenoid that goes in your front brake line, which when you press the brakes, then activate the line lock, it locks the front brakes only, as long as it is on. I've used them in the past, but can't improve my r/t or 60 ft time over the foot brake, comes in handy for the burnout box though, you don't have to fight the rear brakes during your burnout.

doc

Thanks for the responses.

Then how can I stall out the torque converter at a higher engine RPM?

I'm assuming just better brakes.


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'87 L98 TPI IROCZ, AFR190 heads, 3.70 gears, ZZ9 cam, 2400 Art Carr TC, SLP 1 3/4" headers, SLP cat-back, no cat, no AC, no MAF screens, Accel manifold base & SuperRam, Edelbrock double roller timing chain, MSD ext coil & distributor, trans cooler, 52mm TB with airfoil, TB coolant bypass, AFPR(48psi), K&N filters, Hotchkis lowering springs, Car-Pro custom chip, Lay Ind. ram air kit, 265/45R16 Kumho V700 tires.
ET 13.39sec @ 107.21mph
'90 Eagle Talon AWD, no rust thru 9 winters
'99 Camaro SS, red, 6-spd, T-tops, Mcleod clutch, Pro 5.0 shifter, MAF processor, Direct Flow airlid, K&N filter.
313.7Hp & 320.6ft-lbf, ET 13.55sec @ 105.1mph
next mod: 4.10 rear gears

five7kid

iTrader: (14)

You can get an adjustable proportioning valve and set it for more rear brake. You wouldn't be able to do a burnout without a line lock, though. And, you might not like the way it stops on the street.

The big boys use a tranny brake, which internally locks the transmission output shaft. No power to the wheels until you release it. I haven't heard of such a setup for the TH700R4, though. Someone else may know.

By the way, stalling below the converter stall speed isn't all bad. The big boys, again, have a rev limiter tied to their tranny brake to keep the R's a few hundred below the stall speed to let the converter "flash" when the green lights. This gives a bit better jump off the line.

Also, this isn't really a TPI topic, but that's not my call, either.

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82 Berlinetta, orig V-6 car. Rescued w/86 LG4/TH700R with all harnesses, sensors, ECM, etc. 2.73 open. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LB9 w/ZZ3 cam, exhaust, paint, etc.).
57 Bel Air, my 1st car. Currently 396 .030 over, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

rich1034

You also have to look at what your converter is, It may be rated for a higher torque motor. The more torque you have, the higher stall you will have. Also, converters are rated at flash stall, with your foot on the brake, you are not flash stalling the car.

rich1034

Try just bringing the car up to about 1300 rpm, and when the lights green, mash the gas to the floor, that is when you will get your true stall speed. If your tires can handle the jolt.

doc

Yep, you're right, this is not a TPI topic.
Sorry, I forgot that we now have many new topic items.

Once, again, thank you everybody for your responses.