Hi, I have been thinking about putting a 6 speed in my 94 auto with a 396 stroker and wanted to see what other people thought about the performance difference.How much quicker it will be 0-60 better 1/4 mile times.Right now my car has 3.73 gears with a dana 44 conversion.If i did the 6 speed i want to put in 4.11.Do the 6 speed cars pull a lot harder then the auto's.My car shifts good but i feel that a 6 speed will pull my car better.thanks for your replys

 

"pulling" can be refered to gear ratio. The automatic has three things providing a low gear ratio. 1) the 4l60e in yours has a 3.06 first gear vs 2.68 for the ZF6, 2) the torque converter will slip to a higher rpm...typically closer to the peak torque. In a stick car, any slippage is converted to heat in the clutch...thus with less power. 3) after market Torque converters will also multiply the engine torque when under stall...so at the line the wheels see more torque than what the engine is putting out.

So will a zf6 be quicker 0-60=No, 1/4 mile=maybe
The two reasons for going with a stick from an auto is clutch power and efficiency. An auto is less efficient than a stick. 15-20% power loss for an auto, and 10-15% for a manual. Well built auto tranny's fall more toward 20% power loss due to tighter clutches and higher hyd pressures. The ONLY reason I switched from my 700r4 to a ZF6 was that the little tranny never survived and it was cheaper than a 4th rebuild.

Your interest in changing gears is also wise, but not the way that you think. Increasing the rear's numerical gear ratio is a requirement from going to auto to stick...to get the same performance. Remember the converter/auto ratio is much lower ratio (numerically higher) than what a manual tranny presents. Thus your 4.11 gears with a stick is going to performance like a 3.6ish with an automatic.

The real way to determine gear ratio is to look at and optimize the slip at launch, time in high torque band, and RPM at the end of the run. For example, a stock TPI car makes best ET with 2.59 gears, not 3.06's. The reason is that the 2.49 gears forces the Torque converter to slip longer and to stay in the torque band (peak at 3300ish). So for your car, look at if you have tire squeal at launch (too much-numerically high ratio), shift points provides a good access to torque curve. Finally, look at your RPM at the end of the Quarter...does your cam have more or less usefull RPM left? If you have less good rpm, then taller gear (lower numerically) would be the choice. Running out of RPM is typical of high torque strokers. If you have more good/usefull RPM left, then put in a lower (numerically higher) rear gear. This is typical of stock/small displacement need to run at higher rpm for power.

In short, if 1/4 mi is what you want then get a really good torque converter installed. leave the zf6/richmond conversions to the tinker crowd.

 

I am just curious... did you decide to do the conversion to a manual transmission? I have a 94 auto - that currently needs work because it is slipping, so it is coming out of the car! The only question remaining is do I rebuild the automatic or convert to a 6 speed (ZF)? Obviously the rebuild is cheaper (parts wise), but IF I were serious about a manual transmission - it seems like this would be the time to change in out. From what I've seen and read, it does not sound that difficult - provided I get the parts from a "donor" vehicle (so that I can get all of the parts that I need).

If you changed yours out, I'd be interested in hearing the "story"...

 

it will get expensive converting to The ZF.. Unless you have a cheap parts car
the swap will give you much better results unlike the weak 700R4 (4l60E)
the hardest part is getting under the the dash in a C4!!!! the rest is plug and play

 

Thanks for the feedback! Have you done a conversion on a C4 (~1994)?
I found a used one from a 1992 (which would mean that it is almost guaranteed to be the black tag - louder - version, rather than the quieter blue tag version) that is reported to only have ~46k miles on it. It includes everything but the drive shaft and torque tube (C-channel) - not sure if I would need to replace either. Also, I have access to a Dana rear (forget which one - but it is the heavy duty one that is tyically used with the manual transmission - rather than the other one that is used with automatic transmissions). I believe if I change the rear (upgrade) then I need a different drive shaft.
- so the computer does not care if there is no transmission to "talk to" - perhaps it does not require any feedback from the transmission?
It sounds like the hole in the floor for the shifter is different on an automatic (would need to be measured and cut to fit - to convert to the ZF) - although it does not sound like a big deal either.

 

No I purchased mine with the ZF
I just removed the motor and trans to build my 383
a slight challenge removing the ZF
I have converted f-Body's
I have the black tag ZF.. my Buddy had the blue tag.. there is not to much difference in the Whine (or noise) But the black tag is 50 ft-lb stronger has the shorter German made teeth... the blue tag is US made longer teeth and 50 ft-lb weaker<<<<
if you can get the Danna 44 That would compliment your upgrade.. With a much stronger
Diff..
when complete there is nothing better then 100% control on your RPM range..
Good luck with the conversion..!!!!! you will be very Happy you did....
You will need to have someone update your PCM [x] for Manual transmission
and yes you would need to measure the ZF location
there is a How to sticky... on this forum for the Conversion...

 

If you decide to do the swap to a ZF6 and D44, drop me a line if you're looking for a driveshaft.

Live well,

SJW

 

You guys are Great!!! Thanks for all the "tips" and encouragement! Sadly, I think that the Dana 44 (that I have a line on - for a good deal) will not be available for a few weeks (or perhaps months) - it would only put me out during the winter months though, I'd be ready before it gets anywhere near warm again...

Thanks for the feedback on the black tag versus the blue tag ZF6 - makes sense. I've heard that heavier oil in the black tag can quiet it down some (not sure it's the best idea - seems like it would be better to stay with the "recommended" weight oil).

... I did find the notes/instructions from -> http://members.cisdi.com/~anesthes/zf6/
very, very, very interesting (and helpful)! There was another page as well.

I think that I have the driveshaft for the Dana44 rear covered, but if I need one, I greatly appreciate the offer!

Any tips for who or how to have the PCM [x] re-programmed? I have some local friends (corvette enthusiasts) that probably know, but would be interested in your comments as well. I think the worst part is the additional cost to do the conversion (replacing/rebuilding the auto would not be as expensive - but then hey - it would not be as much fun to drive either...).

People tell me to just sell it (my automatic) and buy a vette with a manual, but the majority of the good deals on vettes that I've seen are all automatics! (not to mention the fact that the manuals tend to be more expensive, from my experience...).
If I am going to do it, then I think I want to upgrade the rear as well (to the Dana 44)...
- perhaps I'll soon the the proud owner of a manual C4!

Thanks again! I really appreciate the information/comments!

 

there are many vendors like PCM for less.. that can turn on the manual trans switch..
you could purchase the cable & software tuner cat.. or others.. and change the switch yourself... very easy clicking a [X].. if you upgrade any performance parts you would already have your tune equip... and learn to tune yourself or split the cost and tune with your friends.. copy a bin from the specific year C4. look at and study all the settings and become familiar...
your right it took me months!! to find a 94 ZF... I could find good deals on auto's every day.. if you find the Dana 44 and ZF for a good deal... you should be in the range price difference auto vs Manual.. complete the project yourself.. if you decide to sell your car the value should increase...

 

your car isn't going to 0-60 or et better with a stick. these cars are not fun to launch with a stick nor will the IRS last when blasted on from a stand still whether you have a d44 or not.. your car will be puking rear end parts after a few serious launches. stick with an auto. it will be cheaper in the long run.

 

Have bracket raced my '94 396 LT1 six speed, with 4.09 gears, for ten years in the Pro Muscle class. Very few manual cars in this class.

With 2500 RPM launch on Hoosier DR's get consistent 1.65-1.70 60'. Run to 11.5 1/4 mile, 7.4 1/8 mile dial-in. MPH usually 123-125 1/4, 97-99MPH 1/8. Never busted any rear parts in 10 years.

This is a street and strip C4 that is always driven to the track. Go for the 6 speed IMHO

 

That's why I went to a auto. After many years racing the 6-speed I got tired or rebuilding the rear every 3rd pass.

 

Thanks for the comments guys... I'm not interested in racing my vette, nor am I interested in increasing my 0 to 60 time... Overall I've found it to be fast enough for me (and a blast to drive).

It's a daily driver (and some would argue that is even more of a reason to keep it an automatic) - but I just have always enjoyed driving a manual transmission. I have gotten used to the "shift points" on my automatic - however, sometimes it still catches me and downshifts when I'd prefer that it would not (thus the preference for a manual transmission).

Glad those of you with automatics are pleased with them (agreed sticking with the automatic is more cost effective...), I'm still dreaming of owning one that has a manual transmission...

 

If I wasn't as heavy into dragracing the car would still be a stick.