JMOD & Sniper Tuning Issues

[Lux]

I did the JMOD to the 97 last night. I took the tune off the car beforehand to get an idea of how it shifts stock and I cant believe how people drive these cars without a tuner or jmod...shifts are so lazy and slow. So pulled it into my buddy's shop, we did the jmod. I used the heavy duty springs for the 1-2 (left both in) removed the 2-3 spring, put the new accumulators in (mine already had all the new stuff but it was apart so we used the others anyway.

Well here is my problem, very happy with the jmod and how it shifts. Get a nice little bark on the 1-2 shift with the STOCK tune on the computer. The 2-3 feels nice too. Its not ideally what i'd want without a tune since i love a firm crisp shift but it is MUCH better then stock and shifts almost as firm as the tune by itself.

So this morning i put the Sniper on it, set the shifts as high as they can go and take it for a ride. It no longer will chirp the tires on the 1-2 WOT shift and i'm curious as to why. Dont get me wrong the JMOD is awesome and the shifts are GREAT with the Sniper, im happy with it but wondering how come it wont chirp the tires on the 1-2 shift with the tune on it? I didnt mess with anything else, only the firmness of the shift.

 

[Lux]

also if anyone is interested im selling the Sniper Tuner i have as soon as i get the other bullet back into the multiloader.

 

[XLRVIII]

set the shifts as high as they can go and take it for a ride. It no longer will chirp the tires on the 1-2 WOT shift and i'm curious as to why.

there's no such thing as a "free lunch"...

You realize the transmission pump is a positive displacement pump..right?
So it takes HP to turn the pump.

When you pump the shift pressures up to the MAX, your driving the pump harder than you need to to "complete the shift" properly..
thus giving up HP that would normally spin the tires.

Problem with sniper is you cant choose individual shift pressures for different throttle positions, so when you MAX it out for a WOT shift, your also spinning the pump WAY WAY too much for a part throttle or low throttle shift.

now there might be "part throttle" and low TP shift pressures, but I can assure you they aren't the best way to "get things done".

you only need to add 10-15LBS of 1-2 shift pressure and maybe 10 on the 2-3. the "max" setting in sniper is likely double or triple what you really need.

 

[Lux]

there's no such thing as a "free lunch"...

You realize the transmission pump is a positive displacement pump..right?
So it takes HP to turn the pump.

When you pump the shift pressures up to the MAX, your driving the pump harder than you need to to "complete the shift" properly..
thus giving up HP that would normally spin the tires.

Problem with sniper is you cant choose individual shift pressures for different throttle positions, so when you MAX it out for a WOT shift, your also spinning the pump WAY WAY too much for a part throttle or low throttle shift.

now there might be "part throttle" and low TP shift pressures, but I can assure you they aren't the best way to "get things done".

you only need to add 10-15LBS of 1-2 shift pressure and maybe 10 on the 2-3. the "max" setting in sniper is likely double or triple what you really need.

Thanks tommy, your the man.

After many 1-2 WOT blasts this morning up and down my road i found leaving the tune set at "stock" for the 1-2 shift and maxing out the 2-3 & 3-4 provide the best results.

The 1-2 shift left stock with just the jmod seems like it grabs better, however, with the 1-2 jacked up it shifts harder (pushes the car foward more) but i cant even tell the jmod is there. Ill drive it around with the 1-2 stock for awhile so i can appreciate it the jmod and next time im at the track ill bring the tuner and do a back to back run down the drag strip analysis.

I sent you a pm.

 

[XLRVIII]

I replied to your PM
LMAO

 

[Screw-Rice]

What level Jmod?

 

[LaserSVT]

I was going to post the same thing Tommy did. They build too much pressure together so you need to have the Sniper at mild to stock for the 1-2 shift and dont go above medium for the 2-3 and 3-4 shifts. Anything above that and you may wear the trans pump out.

 

[unity]

With JMod I left my pressures stock. Why do something that is meant to help transmission life just to reverse it? That WHY I did the JMod, better shift, better life. Now shift points on the other hand.....

 

[Lux]

What level Jmod?

Drilled everything out to the highest, except slot #1, couldnt ever find this. There were some flaws in the tech article for the 97.

Left out the 2-3 spring, put heavy duty springs in top and bottom of the 1-2, and new accumulators for both. I probably shoulda left the bottom spring out, but we'll see once i get the 4.10's and eaton in how it shifts.

 

[Lux]

I was going to post the same thing Tommy did. They build too much pressure together so you need to have the Sniper at mild to stock for the 1-2 shift and dont go above medium for the 2-3 and 3-4 shifts. Anything above that and you may wear the trans pump out.

Right on, i thought about his and put the stock setting at the 1-2, and firm for 2-3 and 3-4.

 

[Lux]

With JMod I left my pressures stock. Why do something that is meant to help transmission life just to reverse it? That WHY I did the JMod, better shift, better life. Now shift points on the other hand.....

I hear ya. Once i get some extra time im going to play with the shift points on it.