Just wanted to hear some input on if there was any special tuning mods needed for a stall converter over a factory converter? Seems like there wouldn't be as much of a load showing in the lower RPM's. Should anything be changed drastically in the timing or anything?

 

bumping timing is recomended and youll have to add some fuel to go with it. but added timming upto stall really seems to help throttle response.

 

Approx. how much timing is usually needed? Just wanted to have a ballpark figure. And this would be added to the "Main Spark Advance Vs. RPM. Vs. Load" right, or dist. advance?

 

2-3 max. and diffinately in the low load areas. also the pe might need a bit of work.

 

Funny, but that's about the opposite of what I've done to get a car running properly.

Stall speed has little to do with the low load areas. As RPM increases, the converter will allow the engine to flash to higher rpm, ie the new stall speed. So the high load low rpm area of the timing and VE tables isn't really used with the higher stalling converter.

If you're clever with your tuning, you can run right up to peak torque and stalll speed, without any tire spin. Well using any conventional street tire. Which is the fast way to go. Tire smoke means your wasting energy melting the tires instead of acclerating the car.

 

Any tips on tuning up to stall speed and peak torque? Or just trial and error?

 

so just kill throttle response ?? hmm id try to make the car hook before doing that.ive seen plenty a big block hook on 10.5 inch dot tires with 4500 rpm stall converter pushing well over 500ft lb of Tq with no detuning. so id think maybe working on traction is the better way to go. if you cant get it to hook then take the grumpy road.

 

I don't have to worry about the car hooking right now I am just wanting to concentrate on getting it to cruise smoothly. I just though I could get some insight on accelerating from a dead stop with light to moderate throttle and how and if the ecm tuning needs to be treated differently than if you take off in a stock converter car.

 

Very seldom do I find myself posting something contrary to what Bruce says but this time I find myself doing just that. I found that my 3600 PI Vigilante loves extra spark in the low load / mid-RPM areas (i.e. where the car is just cruising down the road). The extra timing REALLY helped throttle response and made a definite improvement in the driveability of the car. Maybe the difference here is that I am Naturally Aspirated and Bruce is Forced (Turbo)? The Turbo really gets things going whereas a little extra spark on a non-forced induction motor can make a noticeable difference in throttle response during part throttle acceleration. Not sure - just guessing here from what I have seen with my car. I'm running like 50d of timing at some part throttle settings.

Also - I like to tune for as much tire spin as possible (good track / dyno chip!). This has given me the best 60ft at the track. Then, when you are done with this chip, start pulling timing from the high load, low-RPM area in order to get rid of the tire spin. This creates a great street chip for stoplight racing!

Tim

 

I agree ,while bruce is master tuner this is one thing I find him pushing alot.
If you kill you throttle respose - you hurt your stall speed.
Cars run 9's on drag radials,no need to de tune.
I have done it on slippery nights at the track,dropped a few degrees at stall speed to gain some traction and works great.
But if you are hooking then time up.

 

The street rarely if ever affords the traction available at the track.
I was also speacking of where the car was traction limited, the instant traction isn't the limiting factor, then you can get harsher with the tune.

BTW, try it before you think you know better.
I mean thoughly go thru the tune, and spend lots of time with your GTech. That gets away from the guessing.

Might do some reading in Alex Walordy's Holley Book about tuning, gears, engine heat etc..

I've also tuned up some non turbo cars.

And while it's easy to say well your's is a trubo car, if you look at the cooling system in a 231 you'll note that is very similiar to the SBF, with all the inherit advantages they possess.

I had 3 different converters in my 3rd Gen and did some serious playing around with launch stuff. While my 60s weren't spectacular, they were totally consistant, and that's what you want in a stret car. Running a 1.7, and then a 2.7 isn't going to work more then 50% of the time. What confuses alot of people on their 60 times is the 1-2 gear change.

 

grumpy while you are making a solid and sound argument. street traction is not so hard to get ahold of. also maybe doing 2 calibrations one for street tires one for track surface might not be such a bad idea. but i dont think retarding the timing is such a hot idea. if the case is a softer hit to the tires upon WOT then i would say go for cutting back the AE or pumpshot. this will initiate a small bog the same thing as pulling timing however with selecting the correct spot in the enrichment pulses it would be easy enough to go ahead and pull a pulse or 2 and acheive the same results with out the hassles of poor fuel economy and less then stellar throttle reponse form a lazy motor. i just spent a good bit of time working with an s10 with a 3.1. i know what a big deal. but with stock suspension and some mild traction mods it was just smoking the tires all the time. we adjusted the pinion angle got it to hook alot better and then after we exhuasted all the options for traction i pulled some of the AE vs rpm out and it started to hook. its now to where the tires just sort of squeak. there at the limit of traction.

the best part about all of this is the fact the we can both be right. ahh gotta love that.

 

I don't think I would lessen pumpshot to make a bog ,you don't want to lean the car to gain traction. Timing is very effective and safe means of gaining traction.
But if you have the hook,time up.

 

If it's so easy, then you might try working on some cars that make some HP.

S10, with a 3.1?, see my last comment.

I fail to see where you've been correct about anything.

ie reducing Pump Shot, when installing a higher stall converter?, try it some time. then get back to me.

 

sure a 3.1 making roughyl with 3500rpm stall and 220hp in a vehicle with 1280lbs over the rear tires dont hook. i didnt say kill the pump shot. just cut the pulses back a bit usually the first and second pulse is enough to lessen the hit. and grumpy yet again there are lots of way to skin a cat. stop thinking your right all the time and listen to people once and a while. also truck has 195 r14 60 tires. thats a tough truck to hook.

 

First any truck...errr well the SyTy trucks with all wheel are an exception, are tough to hook. Hell my 69 F-100 with a 240 I6 can burn the tires off if I wanted..

Second, well.... you 'll figure out.

 

i did plus got 31mpg highway and 18city. truck hooks throttle is wonderfull and responsive. idle is a perfect 650rpm runs a 12277302 ecm with a ported maf, roller rockes a crane compu cam, 21lb per hr injectors. runs just about 15.1 in the quarter. not to shabby for a pickup truck. with a 3.1 running N/A.

and now i remebered why i dont like pulling timming on a N/A motor itll drive the egt's skyward.had to look at my notes. you can pull some pe timing and this wont hurt much if anything becuase the motor is being smothered in fuel anyways cooling it off a bit. but at PT cruise it drove the egt's on that little 3.1 up over 1500f. not a good plan of attack.ive noticed similar behavior in v8's so i dont go looking at the main spark table as a solution to traction issues.how ever the last few times ive pulled AE pulses ive seen no jump in egt even momentarily so your concerns abotu going lean are pretty nil. not a big deal its pretty instintaneous. the idea is to soften the hit then put the TQ on. eisier and more repeatable from my end going with a redutction in the intial AE pulse then grabbing the 3-5 pulse and pullng it down a bit to keep the engine from ramping up to fast and breaking the limit. your call how you wanna do it. just my 2 cents and what i do.

mind you im not talking huge redutions just a little bit is all that needed. the same as changeing and accelerator pump cam on a holley.

ps bruce btw thats a realy good book.