shadowboy

howdy everyone.

i currently own a 1979 924 with M471 option group.

I bought the car in the midst of modification, and i am going to go slightly beyond the previous owner in terms of engine.

i am got the car with some engine mods done, but i am adding dual valve springs, aluminum retainers, and a cam grind (hardened of course).

my powerband goal is the 4000-7000rpm range. (basically a hot street/autocross car).

my issue, however, is with the gearbox in the car (the 016Z snail shell).

what i am looking for, is a way to optimize the gearing for the new powerband. the stock gear ratios are just too tall, especially for a car with its powerband shifted up 1000-1500rpm.

what i am wondering, is if anyone knows of any alternate transaxles, or at least of any alternate final drives.

ideally, i'd like the ratios tightened up a bit. ive been playing with numbers, and one good alternative solution is to use a ~4.55 or so final drive, with the stock 016Z gear ratios.

or i can use the 79 924 Turbo ratios (which i find to be "slightly" on the tall/wide-spaced side, but not as bad as the snail shell).

i have a few ideas.. but i wanna see what everyone else thinks would work.

Waterguy

I don't know of any Audi 016 trannys that used a shorter final drive than 4.11. You might try searching the Audi boards.

Looking at your ratios, I don't think your problem is so much the final drive as the extremely wide gear ratios they put in your box. It would be a lot more work, but what about swapping out 3rd, 4th and 5th gear sets from a late/ROW 944NA tranny? I believe they would fit, and would result in a much closer-ratio box:

ratio___79 924 ___88-89 944NA

1st______3.60_________3.60
2nd______2.13_________2.13
3rd______1.36_________1.46
4th______0.96_________1.07
5th______0.62_________0.83
F.D._____4.11_________3.89

Definitely would be an improvement, but I don't know about bang-for-the-buck.

shadowboy

thats exactly what i was thinking, but i wasn't sure if the 944 gears would fit.

by the way, the 1979 931 does have a shorter final drive (and taller gear ratios).. but the problem there is that the final drive is too short (5.000). the ideal ratios for what i am going for actually is the late 944 N/A ratios. are you indeed sure the gears will fit onto the shafts in the 924 gearbox?

Tom Carson

have you looked at:

<a href="http://www.924.org/techsection/7transaxle.htm" target="_blank">http://www.924.org/techsection/7transaxle.htm</a>

where much of this is discussed?

also this thread:

<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic;f=15;t=019690#000011" target="_blank">http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic;f=15;t=019690#000011</a>

btw...you may notice a few responses from Scott Vaughan in that thread...he also has the website:

<a href="http://www.924.org" target="_blank">http://www.924.org</a>

Waterguy

I understand that the gear sets swap between 944 and 951 boxes, but I am not sure that they swap with your 924 gearbox. I would expect them to, since they are all Audi 016 boxes, but I don't know how you would verify this.

I have never seen the ratios for a 931; wow, thats a low FD! I guess that helps them get out of the hole with some turbo lag. However, if you can fit those 5.0:1 gears in, maybe Audi made some intermediate sets, like 4.5:1, for their 4000 series cars. Certainly would be an easier swap that three gear sets within the tranny.

shadowboy

i got my gear ratio information from this link:

<a href="http://www.924.org/Downloads/PorscheTrans1.xls" target="_blank">http://www.924.org/Downloads/PorscheTrans1.xls</a>

the transaxle in my 924 is the 016Z transaxle (it is not listed in that spreadsheet).
the gear ratios for 1-4 are the same as the 016/9 audi gearbox, but with a taller 5th gear (0.60). it is a snailshell gearbox as well.

shadowboy

ok... just a quick question. will the 3-5 gearsets on a 1986 944 N/A work on a snailshell gearbox from a 79 924 (016Z transaxle)?

I have a friend locally with an 86 944 with a damaged final drive. I was going to suggest an idea to her that she can buy a used 944 transaxle on ebay or something, and then i can buy her broken transaxle to utilize its 3-5 gearsets.

or alternatively, can i use my 924's final drive to replace the broken one in the 944.

Tom Carson

hmmm..

<a href="http://www.924.org/techsection/transapps.htm" target="_blank">http://www.924.org/techsection/transapps.htm</a>

says "The 016/Y and 016/Z are US and Euro spec versions of a Porsche transaxle identified by the gearset in front of the differential"

the 944 'audi' 016 gearset is behind the differential

shadowboy

yes. that would be the snailshell transaxle (gearset in front of the differential), which is what is in my 924.

Tom Carson

did you check with:

<a href="http://www.924board.org/viewforum.php?f=4" target="_blank">http://www.924board.org/viewforum.php?f=4</a>