Litespeeds Posted June 7, 2009 Share Posted June 7, 2009 I just bought a 1987 944S with an LSD tranny that I was thinking about swapping out the tranny with my 1988 944. Is this legal or not for 944 Spec Racing? Quote Link to comment Share on other sites More sharing options...
Litespeeds Posted June 7, 2009 Author Share Posted June 7, 2009 http://www.clarks-garage.com/shop-manual/trans-04.htm" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; AGR 944 S (1987 -1988) 1st 10:35 (3.500) 2nd 17:35 (2.059) 3rd 25:35 (1.400) 4th 29:30 (1.034) 5th 35:29 (0.829) Rev 12:42 (3.500) FDR 9:35 (3.889) 5Y 944 (1985.5-1988) 1st 10:36 (3.600) 2nd 16:34 (2.1250) 3rd 24:35 (1.4583) 4th 28:30 (1.0714) 5th 35:29 (0.8286) Rev 12:42 (3.500) FDR 9:35 (3.8889) Quote Link to comment Share on other sites More sharing options...
mcmmotorsports Posted June 7, 2009 Share Posted June 7, 2009 13.2 Differential The stock 3.889 (9:35) final drive ratio must be used. Differentials are free. 13.3 Transmission 13.2.1 First through fourth gears must remain stock for the Porsche 1983-1988 944 naturally aspirated and 924S models. Updating to the stock shorter fifth gear from the 924S and the 1988 944 is allowed. The allowed gear ratios (gear tooth count) are: First 3.6000 (10:36) Second 2.1250 (16:34) Third 1.4583 (24:35) Fourth 1.0714 (28:30) Fifth 0.7297 (37:27) or 0.8286 (35:29) So, with that said, the LSD is legal, the gears are not. So no, a 944S LSD TRANNY is not 944-SPEC legal. Quote Link to comment Share on other sites More sharing options...
Big Dog Posted June 8, 2009 Share Posted June 8, 2009 Can the dif be swaped into the 944 tranny or can the gear set from the 944 be swapped into the LSD tranny? Joe, what do you think? How do we get this done before Infinion later this month? No excuses for Nor. Cal. Big Dog Quote Link to comment Share on other sites More sharing options...
Litespeeds Posted June 8, 2009 Author Share Posted June 8, 2009 Sounds like too much work. I was hoping for a quick and easy tranny swap, not taking each one apart to swap out the differential. I guess no LSD for my 1988. There is no excuse because I do have a factory LSD on my 1983 spec car that I put in last year. But that doesn't make me much faster. Quote Link to comment Share on other sites More sharing options...
roberth944 Posted June 8, 2009 Share Posted June 8, 2009 Jim, It is easiest to put the lsd into the 1988 trans. The gears and shafts are different from the 2 trannys. only the short fifth can be used and the diff can be swapped. If you need this done I can help you. I have done quite a few of these trannys. Rob Quote Link to comment Share on other sites More sharing options...
944-Spec#94 Posted June 8, 2009 Share Posted June 8, 2009 Can the dif be swaped into the 944 tranny or can the gear set from the 944 be swapped into the LSD tranny? Joe, what do you think? How do we get this done before Infinion later this month? No excuses for Nor. Cal. Big Dog Yes the diff can be swapped. In this case the diff and the final drive are the same. Quote Link to comment Share on other sites More sharing options...
Big Dog Posted June 8, 2009 Share Posted June 8, 2009 Thanks for the offer Robert but the trans is in Nor. Cal. If you are not faster with the LSD then you need to have Charlie work with you at Infinion because it should pick you up at least 1/2 a second or more at that track. Charlie has been helping me at Willow Springs and he has made me faster. Now he says he won't help me any more. I guess I will have to "assist" his setup to get closer to him. The only problem with that is he stays at the track so it is harder to "help" him at night. Big Dog Quote Link to comment Share on other sites More sharing options...
Litespeeds Posted June 8, 2009 Author Share Posted June 8, 2009 If an LSD is only going to make about a 1/2 second faster, then I guess I do notice the difference. I was thinking that it would make about a 2 second difference or something really big like that. I do feel more confident with having a LSD than not, especially going through turn 2 at Infineon. Quote Link to comment Share on other sites More sharing options...
944-Spec#94 Posted June 8, 2009 Share Posted June 8, 2009 How much a difference an LSD makes it really anyones guess. There are many migitating factors in the numbers people quote. Driver skill, car set-up, and tracks are all major factors. I have run with an open diff for almost 10 years. Over that time I have adapted my set-up and driving style for an open diff and been able to make the most of it. However if I get one I can't see gaining alot of time at my home track. The best guys that run there are not 2 seconds fast than me so getting that much is probably not going to happen. May be 1/2 second. Maybe not. Frankly I expect I would be slower with an LSD for at least the first weekend. I will need to re-setup the car and learn how to take advantage of it. It may take a while to learn how not to get too much understeer at turn in. Now I do think I will be faster with one, but now how much faster is a great mystery. BTW... I have not even brought up the differences between a worn out stock, rebuilt stock or new gaurd LSD. Quote Link to comment Share on other sites More sharing options...
Cheap_Thrills Posted June 8, 2009 Share Posted June 8, 2009 If an LSD is only going to make about a 1/2 second faster, then I guess I do notice the difference. I was thinking that it would make about a 2 second difference or something really big like that. I do feel more confident with having a LSD than not, especially going through turn 2 at Infineon. I know my spongy suspension probably has alot to do with it, but I always spin my open diff's inside tire exiting turn 11 at Infineon and have to back off throttle. I assumed LSD's extra grip there would be a big plus. Quote Link to comment Share on other sites More sharing options...
944-Spec#94 Posted June 8, 2009 Share Posted June 8, 2009 If an LSD is only going to make about a 1/2 second faster, then I guess I do notice the difference. I was thinking that it would make about a 2 second difference or something really big like that. I do feel more confident with having a LSD than not, especially going through turn 2 at Infineon. I know my spongy suspension probably has alot to do with it, but I always spin my open diff's inside tire exiting turn 11 at Infineon and have to back off throttle. I assumed LSD's extra grip there would be a big plus. Every track is different as is every car and driver. There is alot you can do with the chassis to improve rear grip as well as by changing the line and how you apply power. Even then those changes can hurt the car in other places. So how much time you pick up with an LSD is really guess. At a place like willow springs or miller you don't get any wheelspin. So the LSD not important for power. However it will help under braking. Turn 1 at Miller and probably turn 5. At Willow turn 9 and probably turn 1. At PIR an open diff hurts in turn 2 underbraking and at turn 7 on power out. Turn 9 power out can hurt, but a few tweaks to line and they way you put put down makes a big difference. I have been able to out drag cars from 9 who have an LSD as compared to my open one just by adjusting my line. Here is a tip. Stiff front bars limit the drawbacks of an open diff to some degree. Sure the impact handling every where, but chassis set-up is a compomise. Quote Link to comment Share on other sites More sharing options...
cbuzz Posted June 8, 2009 Share Posted June 8, 2009 Big Dog does my car need to go in the trailer at night? Since I have not been to Infineon for many years I am not sure what to expect. Last time there the key for me was to get wheels on the berms. This seemed to be where the traction was. The racing line was very tight. Nascar will be running the weekend before us so who knows what that will do to the track. That said I will be happy to share what I know (or think I know). Charlie Quote Link to comment Share on other sites More sharing options...
Big Dog Posted June 9, 2009 Share Posted June 9, 2009 Charlie, unless you value my midnight setup changes, YES, YES you do need to put your car into a locked trailer at night. Jim Quote Link to comment Share on other sites More sharing options...
cbuzz Posted June 9, 2009 Share Posted June 9, 2009 Now you know why I always bring two crew guys. One to keep an eye on the car and one to make me dinner Quote Link to comment Share on other sites More sharing options...
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