Can Better Brakes Lower Your E.T By Increasing Stall?

[Fourtraxjay]

Hello,

In my quest to get my truck into the 12's, I am trying to finalze my set up prior to my next dragstrip trip.

 

Last time I was there.

13.6. with a built tranny with a 2600 stall.

When I would go to launch the truck, I could not get the rpm's much past 2000 without the truck 'creaping' on the brakes. (brakes mashed to the floor)

 

i have 14 oversized rotors all around.

Could better pads provide better holding force at the line, thus allowing me to get the engine closer to its stall speed, thus lowering my E.T?

 

thanks

Jay

[misterp]

Which brand/model of converter are you using exactly? The truck is Radix superchared right? What were your 60-ft times and 1/4-mile MPH?

 

This admittedly is hindsight talking - but I would have installed a good 2800-RPM converter in that combo; but (for comparison) BroBrad's truck runs mid-12's and I think he has a TCS-2600 installed in his truck. Generally speaking, for these trucks to run in the 12's you need to have a 60-ft time down in the low 1.8's (or better).

 

Almost all of us get better 60-ft times launching from just above idle, with many converters the motor will usually 'flare' or 'flash' the RPM over the rated stall speed; other converters won't flash above the rated stall speed, it all has to do with the internal construction of the converter.

 

Mr. P.

Edited June 1, 2011 by Mr. P. (see edit history)

[Krambo]

Almost all of us get better 60-ft times launching from just above idle, with many converters the motor will usually 'flare' or 'flash' the RPM over the rated stall speed; other converters won't flash above the rated stall speed, it all has to do with the internal construction of the converter.

 

Mr. P.

 

 

Agree. All set-ups are different however speaking from direct experience with a magnacharged 6.0L / AWD platform and multiple converters, launching just over idle gave me the best 60ft and overall E.T. The converters I experimented with:

 

1. Yank 3000TT

2. Yank 2600TT

3. PI 2800 Vig 3 disk

 

The Yank 3000TT was the worst for 60ft, the TT2600 lasted several hundred miles before exploding however gave better 60's than the 3000 and the PI gave a easy full tenth better than the 3000TT yank.

[Fourtraxjay]

Thanks for the tips guys.

Yes, I have the radix, dynatech longtube w hi flow, magnaflow cat back, volant cai-no scoop, built tranny,

 

i honestly would probably never tried launching just above idle.

I understand how this could work well with the 'flashing' you describe.

 

The tranny shop who built my tranny strongly urged me to stay at 2600 not 2800 for a daily driver. I did not want to argue with them as I don't know trannies like I know engines.

Brand of converter. when I discussed different brands, they said they would use 'their guy' for the converter, so I do not know specifics of it.

 

I really like the way it drives/ shifts, so I am not complaining at all about the tranny build. The guys at the shop are really good to me.

 

Ok for 60ft times. the printer at the srip was using an ink cartridge from 1998 and I can barely make it out.

I will say the AWD at 60ft is really fun next to faster cars while then attempt to chase you down every run!!

 

best run was:

Reaction time: 17minutes. ok not really but I gotta get better at this!! .571

60ft 1.906

330: 5.552

1/8: 8.618

mph:79.63

1000:11.319

1/4:13.613

mph:98.44

 

 

this was with the tow haul button.

Stock maggie tune, other than I copied pasted the stock 1-2 base pressue table from the stock tune to soften shifts.

Engine still showed misfires above 2400rpm that has since been resolved with crank re learn. but i don't think these false misfires reduced power.

 

Since this run. I have planed for a return trip this year with the following additions:

E fan conversion.

Put 1-2 base pressue back to maggie tune level.

pinned crank

3' pully down from 3.3

Beltech 2/2 drop.

 

once I get the 3.00 pulley on, I'll get a tune done.

I am asking alot (over 1/2 second) from the pulley and tune, but now that I have a better idea how to launch, that should help to.

 

I won't waste money tryin to improve the already good brakes.

 

thanks guys

 

Jay

[NORCAL SS]

shops crank me up. My wife has a ptb3600 stall in her truck and there IS NO problem. Lots of shops arent up to date on stalls now a days and we are in san francisco where its all hills.

 

With the maggie trucks ive played with yank sc3000 stall works wonders.

 

also if you did 275 40 17 mt drag rads all around you would be in the 12s with no problems.

 

vig conveters ive had issues with very loose and dont 60 foot as well as the yanks ive done on the sss. Main this is DO NOT get the tt version or the sstb stall. PTB is a better stall more streetable and cuts great times.

[misterp]

best run was:

Reaction time: 17minutes. ok not really but ...

 

the printer at the srip was using an ink cartridge from 1998 and I can barely make it out...

 

Like your sense of humor. And I'm thinking that North Texas Raceway must be sharing that cartridge with them; don't you love it when you can't read the original receipt but can read the carbon copy?!

 

The tranny shop ... urged me to stay at 2600 not 2800 for a daily driver...

The reason they did that is because they didn't want to risk you breaking their trans (with a converter having a higher STR).

 

60ft 1.906

1/4:13.613

mph:98.44

...this was with the tow haul button.

Not bad - definitely can be improved; the tune, 3.0-inch pulley, and 29" drag radials will help a bunch but without hearing exactly the brand/model of the converter I can't speculate how much more the 60-ft could be improved. I also cannot speculate about your trans without knowing exactly what's in it. But I do know the tow/haul button costs you performance, you would have run faster in 'normal' shifting mode, assuming the tune & shiftpoints are set right.

 

Stock maggie tune, other than I copied pasted the stock 1-2 base pressue table from the stock tune to soften shifts...

GOOD run the OEM pressure tables on the 4L60, we highly recommend this and strongly discourage raising the pressures via the tune; we instead build the valve body and hydraulics to work with the factory PCM transmission pressure tables/settings. We do recommend zeroing-out the adaptive tables (or, lowering them to 0.2-secs across the board), and removing most of the torque management but not all of it in our 4L60 builds.

 

...I have planed for a return trip this year with the following additions:

E fan conversion.

Put 1-2 base pressue back to maggie tune level.

pinned crank

3' pully down from 3.3

Beltech 2/2 drop.

once I get the 3.00 pulley on, I'll get a tune done.

I am asking alot (over 1/2 second) from the pulley and tune, but now that I have a better idea how to launch, that should help to.

The crank pinning is critical, you need to do that asap. When you get the tune done, ask that the EFan settings be enabled in the PCM before you actually install the efans. Before I can get more in-depth I would need to know more trans and converter specifics, like what shift kit is in the transmission, did they do any main drum high-RPM oil control mods, etc. But IMO with the efans and 3" pulley and tune there is no reason the truck shouldn't run solid high-12s, if not even mid-12s (depending on transmission & converter behavior).

 

Do you have a wideband on the truck? If not, get one before tuning, I highly recommend the NGK AFX ($270) because it is dialed-in to be most accurate between 11 and 12 to 1 AFR. You said that you are modifying trans parameters in the PCM, what tuning software are you using, or are you using a handheld tuner to do this?

 

Mr. P.

Edited June 1, 2011 by Mr. P. (see edit history)

[Fourtraxjay]

Thanks for the input people.

 

I already pinned the crank.

"did they do any main drum high-RPM oil control mods, etc"- I doubt it.

 

I got very little out of the shop regarding the torque converter. I assumed part of the stal chioce. was for reliablilty,

 

I had read, and started to believe about putting the base pressues back to stock.

I only did this for 1/2 shift, should I do it for the rest of them?

 

I guess I need a tune then, because if you say tow haul should slow me down, it is the opposite. I consistently ran .1-.2 better with the two haul button on.

 

The tow haul button only affects shifts right? the engine parameters are unchanged correct?

If my tow haul parameters raise shift points, increase line pressure, etc. why wouldn't it be faster?

I don't haul anyting heavy, I could probably do without a haul button, but If i can program normal shifts for daily driving, then have the tow haul button set up for best e.t. wouldn't that be the best way?

i wish I could tell you more with the tranny. When I suggested supplying my own, they said sure, but any problems you have with it, we have to charge you to fix. If you use "our guys' converter we will cover all the costs of fixing replacing it.

Incidentally, After I first picked it up. the torque lock up would stick on when it got warm. they fixed it n/c,

 

here's is the items on the tanny invoice.

Gm 4l65E trans overhaul

2600 stall torque converter

deluxe overhaul kit

boost valve/ sleeve, high performance, sungear shell

Force motor

Transgo stage 2 shift kit

fluids, labor, etc.

 

He also told me that the 'hd clutch pack" they installed increases number of clutch plates sigificantly because the 65e already had more plates than the older 60's, so mine has 7?

 

Mr. P. I know, I know, you keep urging me to get a wide band. I will one day, but this 12 second truck project is 1 of many I have on the go and I want to have time to dedicate to learning it before I keep throwing money at it and having the wide band sit on the shelf while other projects take up time.

Anybody ever hear of a '66 yenko stinger? (yes I think corvairs are lame as well, but this was another of my father's old treasures) It had the Crown conversion, Mid engine set up with 302 chevy in back seat.

the wrenches gotta start spinning on that now.... I hope the SSS doesn't need much more to get a 12.99!!

[misterp]

...putting the base pressues back to stock...should I do it for the rest of them?

The 'correct' answer here is - do exactly what your transmission professional specifies. Beyond that, I should not discuss what your application may or may not require without knowing exactly what was done (or not done) with the hydraulic circuits in the unit. Best I can offer is, log your runs and make sure your shifts are ideally 0.2-seconds, no more then 0.3-seconds - if they are take that as a sign of slippage and expect trouble later.

 

...if you say tow haul should slow me down, it is the opposite. I consistently ran .1-.2 better with the two haul button on. The tow haul button only affects shifts right? the engine parameters are unchanged correct? If my tow haul parameters raise shift points, increase line pressure, etc. why wouldn't it be faster? ...

Yup you need a tune, unless you have changed the T/H shift points from stock. The PCM has two parallel sets of parameter tables for trans shift points, and trans shift pressures - these are selectable on-the-fly via the T/H button; from the factory, the T/H button OFF sets shift points higher so that the trans is shifting at the engine's best horsepower (5500+ RPM), with the T/H button ON, the trans shifts at the engine's best torque (4500-ish). In other words, with the T/H button on, the PCM is short-shifting the trans; if that is faster than using the upper-RPM of the engine, then the motor is weak in those upper RPMs, meaning you have either a poor spark table calibration, knock retard, poor fuel delivery (AFR), or a combination of any/all three. This needs to be addressed, it is proven fact when an engine is making best performance, it is also running with a calibration giving you best reliability.

 

He also told me that the 'hd clutch pack" they installed increases number of clutch plates sigificantly because the 65e already had more plates than the older 60's, so mine has 7?

Your truck came with a 4L65 - it already had 7 frictions in the 3/4 clutch pack from the factory. We get nine in our builds. Your truck also came with the 5-pinion planets. I also got this kind of statement from my first transmission "professional", they told me they had replaced the 4-pinion planetary gearsets in my trans with 5-pinion parts, at a cost of $500, when the trans already had them stock.

 

Mr. P. I know, I know, you keep urging me to get a wide band. I will one day...

OK very cool, keep your foot under control until then!

 

...Anybody ever hear of a '66 yenko stinger? ...

Nope - post pics!!!

 

Mr. P.