Maciek

I don't know whether I misunderstood Special Tool, but if I understood him correctly that he has an S2 gearbox in his car, I don't know if his modifications help him hit 70 mph at a lower RPM. I have an S2 gearbox in my car and I am at about 3100 rpm at 70 mph. I am MUCH closer to stock then he is, so that could be the reason for the difference.

lleroyb

2850 is my engine speed at 70 with the stock wheels and 245/45s in the back. I was expecting something over 3000 with a 951 5th gear and an S2 ring and pinion. How come your revs are so low? Big tires?

Lou

Mike B

Thanks Erik...I was afraid of that...Did you say beer? Soon...I would love a ride in your car before she is parked for the winter...I'll send you a pm.

special tool

I have an S2 transmission. I do not have the 951 5th - but it is a good mod.

You cannot judge your RPM/speed on the pos tach in these cars - they can be off as much as 400 RPM, from a signal taken off of #1.

My RPM at 70 is 2850 - this is read from my datalogger. It also corresponds nicely with the Porsche speed/RPM figure of the S2 transmssion 5th which is
24.5 MPH per 1000 RPM.

lleroyb

"I have an S2 transmission. I do not have the 951 5th - but it is a good mod."

Sometimes I wish I could read, it's a valuable skill.

Funny you should mention the tach because I swear when I first got the car it was more like 2750 at 70. I was just checking it since the price of gas went up, most definitely 2850 on flat ground.

Do you think it might actually be less??? Everything that should effect that number is stock.

Lou

Thom

What is the best mod in the end for a modded 951 :
1) fitting a S2 tranny ?
2) fitting a S2 R&P in a 951 tranny ?

Frank@Work

I also would like to know!

I have a S2 LSD tranny lying in the garage.

special tool

Putting the 951 5th makes the 4th-5th change into a closer ratio because the 951 5th is shorter. 1-4 gears are exactly the same.
You will sacrifice top end slightly, but who cares in the US?

Maciek

To clarify, my RPM numbers were based off the "POS" stock tachometer. I don't have a datalogger so this is as accurate as I can be.

tifosiman

Installing an S2 R&P into a 951 trans is a lot of work and expense. Special tools, new shims, trial and error, labor, etc. You are better off getting a S2 trans like Scott and just swapping the whole thing in, or, if the 951 5th matters, install the 951 5th into the S2 trans (not that difficult by comparison to swapping the R&P).

special tool

I agree with Tifo, unless you have a big race budget, just get the whole S2.

User 41221

Just to clairify, mine is an '86 951 LSD tranny that had the S2 r&p added, clutches went from 40% to 80% locking, and it got new carrier bearings, etc... I spent some time driving around yesterday with it, the more I drive it, the more I like it.

Regards,

jean_noir

abracadabra s2 ring and pinion only $1095.00

http://www.944online.com/cgi-local/A...smission-944s2


anyone down for a group buy?
what else would we need to purchase?

tifosiman

A lot.

Hydraulic press
many special tools (I can give you a long itemized list if you want it)
Hot plate
New shims, seals, and bearings (while it is cracked apart why not)
Lots of time (to get the R&P shimmed just right, it will take several tries)

By the time you bought all of the above, you could have just paid a shop to do the work and had money left over for groceries.

Like I stated before, this isn't easy. And if it isn't done just perfect, that shiny new R&P will turn into metal granola in no time at all.

lleroyb

Not something I would undertake at home, but it is worth considering. It seems like a great idea if you stay under 120 most of the time, like me.

Lou