Dennis, or any other EEC IV ghurus-

BlackIceLSC

Registered
I have a 94 Mark VIII with a JMOD, and stock ECU. I also have a 95 Mark VIII with a "Dennis" chip, and NO JMOD. Both cars have different catch codes on their ECU's.

My question is, can I swap ECU's from the 95, into the 94? If so, do I have to worry about my shifts being TOO firm by using a ECU with a chip in a car that has a JMOD?

I plan on drag racing this car every now and then, and would love the "extra" power from a chip. I just cant afford one in my 94 right now. Thats why I would like to know if I can simply swap ECU's from a 94 to a 95 without changing anything.

Also, if I can, will the HARDER shifts from both JMOD and chip be too rough on the tranny?

I know I will have to manually shift the car if I can swap ECU's, because W.O.T. shifts at 7000rpm(from the chip) are way to hard on a stock torque converter!

Thanks gang. If anyone knows FOR SURE, just let me know. :)

[a BlackIceLSC-VP LODNCA
http://mark8.org/lodnca
94 Black/Black M8
95 Champagne/Saddle M8
http://www.markviii.org/~blackicelsc/lodcard2.JPG
see profile for mods[/a]​
 
RE: Dennis, or any other EEC IV ghurus-

there should be no problem with swapping the EEc's that i can think of. All you have to do is disconnect the battery and then take the 8mm bolt loose that holds the main harness to the EEC.
 
RE: Dennis, or any other EEC IV ghurus-

Thanks Pony. When I first did my JMOD, I left the lower 1-2 spring out, and it shifted way too hard for my "peace of mind". I know alot of others have run their cars with a chip, JMOD, and no lower 1-2 spring, and have had no problems. I just thought that "SNAP" shift was gonna hurt something real bad. especially how hard it hit at W.O.T. Soon after, I went back in there and put the new lower 1-2 spring back in. Now it shifts perfect. hard shifts at heavy throttle, but quick and slightly firm shifts at part throttle. It easily chirps the tires into second at heavy throttle. I also left the 2-3 spring out, and my 2-3 shift is PERFECT.

Do you think if I swap computers, having a chip AND a JMOD, it will shift TOO hard? I certainly dont want to break anything, but I love the "no-timing-retard at shift point" feature of the chip. The car just never stops pulling. But, I do worry about breaking/damaging the driveline with a JMOD and a CHIP controlling the shifts.

Thanks. Also, with a chip I have the 7000 rpms shift point at W.O.T., pretty bad for the stock torque converter, isnt it?

[a BlackIceLSC-VP LODNCA
http://mark8.org/lodnca
94 Black/Black M8
95 Champagne/Saddle M8
http://www.markviii.org/~blackicelsc/lodcard2.JPG
see profile for mods[/a]​
 
RE: Dennis, or any other EEC IV ghurus-

The car doesn't make any more power after 6K so I don't understand the 7K shifts? Craig, what's the reason you shift at 7K? Not a flame, just curious.

Bryan
MonsterMark
 
RE: Dennis, or any other EEC IV ghurus-

I thought the same thing Bryan, but who knows with a burned chip? It could be aggressive enough a/f burn to support 7k w/o going way lean. Mr Dyno would know if there is power up there. IMHO 6.5 - 7k = tick tock tick tock... with a stock TC though.
 
RE: Dennis, or any other EEC IV ghurus-

I follow the argument of the shift point being too high at 6500 to 7000, but isn't part of the answer where the rpms are after the shift? Don't you want to pick up where you left off with the most power available in the next gear?
 
RE: Dennis, or any other EEC IV ghurus-

Agreed, but if your converter can't handle it, it is like slipping the clutch at 5K and then dropping it. Very bad for drivetrain components and I don't think you will gain much from doing it. With the proper tranny mods you should still be able to hold 3800 rpm with a WOT shift at 6K. Still well into the powerband.IMHO

Bryan
MonsterMark
 
RE: Dennis, or any other EEC IV ghurus-

I agree JP. Keep it where the hp/tq will do some good.

On the 98 4R70W, gear ratio's are:

1st = 2.85 to 1
2nd = 1.55 to 1
3rd = 1.00 to 1
4th = 0.70 to 1
Rev = 2.32 to 1

IMHO, with this info, and 3.27 to 1 rear gear ratio for a LSC, a good tuner can keep you in the power band, and make the most of what you got. I still believe the TC is the weak link, and will have you walking if you put your nose in the 6.5 - 7k range without any mods.
 
RE: Dennis, or any other EEC IV ghurus-

I found a Dennis chip for sale, used matching our 95's catch code. It is a "basic" burn. I bought it from Jeremi(Madgen1) a couple months ago.

I slapped it in the 95, and then drove the snot out of it to 'teach" the car the new settings. I noticed on the highway, at 75-80 mph, the car easily does the 3-2 shift, but since the tranny is STOCK, I elect not to do that.(i wont do a 4-2 WOT kick down shift. no siree)

I also noticed the 7000 rpm WOT shift point. The car pulls hard all the way up to the 7k mark, but I soon realized that isnt what I want. manually shifting the car at 6k will ease the strain on the T/C, but we all know that a W.O.T. manual 1-2 shift is equally as bad for the trans anyway.

I love the chip, and I seriously want one for my 94, which prompted my inquiry. However, it is a matter that is rarely discussed. You read about people getting "chips" ordered all day long, but the topic of T/C ballooning is NEVER discussed in the same sentence.

I have a heavy right foot. I recently did the full-on 1-2, 2-3, JMOD(350), mercon V, and new 96+ pan. I did this so I can "get on it" and not worry about my tranny not being up to the task(plus my lower 1-2 was shot already)

is my luck any better with the chip and my JMOD, manually shifting the 1-2 at, say 6500, or should I just avoid it all together, and opt for a T/C replacement?

I appreciate you guys bringing the T/C into the equation. it is one of the most forgotten components in any A/T car, unless the drag strip is often played on. then it suddenly becomes a priority. I just want to play, and not worry about grenading my slush-box after 1 too many W.O.T. shifts.

Thanks guys.

[a BlackIceLSC-VP LODNCA
http://mark8.org/lodnca
94 Black/Black M8
95 Champagne/Saddle M8
http://www.markviii.org/~blackicelsc/lodcard2.JPG
see profile for mods[/a]​
 
RE: Dennis, or any other EEC IV ghurus-

Manual 1-2 shifts aren't really bad for the tranny. If anything, the shorter time it takes to shift is better for the tranny. 3-1 and 4-2 downshifts, on the other hand, aren't all that great for it.
 
RE: Dennis, or any other EEC IV ghurus-

Here is where I believe it's at. With a perfect shift(impossible) the shift point at first and the RPMs at second:

5500rpm(1st)-2991rpm(2nd)
6000rpm(1st)-3263rpm(2nd)
6500rpm(1st)-3535rpm(2nd)
7000rpm(1st)-3807rpm(2nd)

...and those are the most rpms you will begin 2nd gear with. With the wide-ratio automatic, the jump from 2.85:1 in first gear to 1.55:1 in second gear is(for the lack of a better word...) wide. Looking at the above numbers, where do you think the best shift point is - based on the beginning rpms for second gear?

Boy, how did this post get off on this mathematical tangent?
 
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