Jeremy:

Thank you for taking the time to organize the fact based posts from the experts to whom I was referring.

This is solid information for G50 Carrera owners that are "weighing" their performance upgrade options.

Mike

I have a stock 3.2, with a 7:31 915 tranny and light flywheel. It's in a 2200 pound 1973 coupe.

I'll gladly take on a 350Z, but only at the track.

Street racing is kewl

For a little bit more on the cheap. Removing everything form the front trunk is 50 lbs. Replacing the 65 lb battery w a 15-20 lb race unit. Take the rear seat backs and lap belt hard ware out for a total of about 100 less weight.

Choosing the right tires can add a small gearing advantage. Stock is about 25" tall. There are tires down to 24" or less that can work on the car. Mich Sport Cup tires are lighter that most but expensive.

Adding a second exhaust pipe to the passenger side to mirror the driver side can add up to about 7HP if the chip is matched. Or get a good sport muffler. A freind has a car just like mine but w a Bursh muffler and he gets about 5-7HP more than me on the same dyno on the same day.

Make sure your car is well maintained w a clean air filter. Good plugs, wires, and valve adjustment.

Then get you car on a dyno, upplug the O2, have them put there wide band 02 in its place and verify your A/F ratios. If not ideal, send them to Steve to get them right.

If ya want to spend more, weight reduction and gears as noted are the big ones. A light clutch pack would be nice and will add HP on the dyno.

Cams might add a little HP up top but should have lighter valve retainers added and / or up graded springs to match. If you are going to spend much time around 7000rpms you should put stronger rod bolts in as they are a known weak point.

SSI headers add a bit around 3000rpms but are smaller than stock so don't add much up top.

Then there is the low boost turbo conversion for about 340HP... ;)

Just my two cents.

Or, for drag racing, get a Mustang.

And stop racing on the street before someone gets hurt.

Sure, a built Mg cased 915 is a "pricey alternative to [a] G50" BUT be careful when calculating the wt. penalty - it is "small" when compared with a late model Al cased 915; but larger when compared with what I stated - a Mg cased 915.

If you race, then you are going to rebuild the trans. eventually anyway.

If you drag race, then you are going to rebuild the trans. very soon anyway.


If this table formats properly, you will see that the Quoted "only 15-20 lbs." above is WAY WAY off. Try 50 lbs.!


Transmission Year Weight (lb) Input Torque max. (ft-lb.) Clutch Plate Dia. (mm) Notes
901 - 1968 75 215
901 1969 148.5 1 215
911 1970-71 225 2 wider gear rings than type 901
915 - early 1972- 125 181 3 rel. to 901, 911 has reinforced bearings, roller bearings, ball bearings; gear shaft spacing increased, wider gears; two shafts supported by six bearings (prior was 4)
915 – w/ pump 275
G-50 1987 1755 221
964 trans 145.5 with oil
993 6 speed trans 145.5 with oil4

1 die-cast housing replaced the earlier sand cast housing, allowing more input torque (Frere, p. 114)
2 “pull clutch” - blade tips of diaphragm spring located in the cover, so pressure plate pushed by blades along a smaller radius, giving better leverage, with less force required by driver to release the clutch (Frere, p. 114)
3 Frere, p. 120 – higher torques can be handled with a reinforced final drive and a pump to circulate oil through a cooler and to spray the most stressed gears and crown wheel and pinion assembly; the 275 ft-lb. figure is for racing where long term wear is not a concern.
4 Excellence, June 1999, p. 28
5 The 1995 993 trans. weighed the same as the previous 5-speed in the 964 at 145.5 lbs (with oil). Excl. April 1994, p. 77. Gearbox casings are thin wall, pressure cast Al; the pinion shaft is gun-drilled, and the ring gear forging has pockets to reduce wt. – P AG says all these are firsts for a production road car.

Ok, here is an image of the table instead:http://forums.pelicanparts.com/uploa...1221583535.gif


- same footnotes apply


As you can see, the G-50 is a Porker!

Randy:

I was off by 5 lbs according to Tyson Schmidt's data. And I clearly stated "I believe Tyson Scmidt found a 15-20 lb difference". I then suggested that Brandon research Tyson's posts to find the exact numbers he came up with.

The issue really comes down to what you want to place more stock in, your data table or real world experience and findings from people such as Tyson Schmidt and Peter Zimmerman.

I don't know about you Randy, but I think I will stick with what Peter and Tyson have to say.

Mike

All advice has been great, but aking it could be comparable to walking around with blinders on. For the money you will likely spend to top out your car, your friend could bolt a supercharger on his 350Z and you will never touch him in a straight line. He could also remove weight.

If you want a car that is fast given modern day standards, you should just like totally buy a modern car. (Apologies for the jab - but please don't write in common vernacular. It is a sign of poor intelligence)

You need to go back and read the info you posted more carefully. Both are comparing the very last of the 915s (the heaviest ones) with the G50. Now, go back and re-read what I said about wt. variance in different versions of the 915.


Again - look at the footnotes on the data table. They give the sources, which are highly reputable. I would also want to see the methodology that others used, and be sure the scales they used are calibrated.

The aside you quoted about the Al cased transmissions being stronger than the Mg cased ones is not really true according to what I've seen. It appears the MG cased ones are stronger b/c of the steel bearing /plates used. 2p ag dispensed with those on the Al cased trannys. There is a thread on that somewhere.

Another source of data would be to collect a bunch of Porsche's Tech Spec books. If people will post scans of the trans. wts. from various years, I will collate them and tabulate.

If people would like to send me an assortment of transmissions, I will be glad to weigh each one accurately on a calibrated scale and then return all the ones I don't want to keep.

NOS, but don't use it too early or the Z will whoop you.
I learned that from Vin Diesel.

wanna play "that" game,..get a turbo for starters...

..otherwise , seemingly misguided. As kick7ca

alluded,...(that is, top of 4th..) ? Streets?

It's JUST NOT about this "redlight stuff".....but a turbo could help with the redlight endeavors...


Best,

Doyle

Thanks for all the help.

911st, i like a lot of your advice, I'm prob going to go with some of the things you said in your post. I tried looking for turbo kits but i couldn't find any for the 3.2 motor. I dot plan on doing it anytime soon but i would like to see some of them.

For 3.2 turbo kits do a search on "protomotive."

Also i know this sounds lame, but check if you are getting full throttle. More than enough drivers out there end up finding out they aren't getting full throttle when they buy a performance chip and it says in the instructions to check full throttle in which case they do and their blown away after it is corrected.

In my case, I found out i wasnt getting full throttle. Turned out the ball on the throttle linkage wasn't in the cup on the back of the gas pedal, but just resting in one of the diamond squares. I drove the car like this for 2 years after i bought it in 2006 not realizing. I guess the previous owner sold me the car thinking it "got slow" after he might've fussed with the gas pedal, but me not ever owning one of these before thought it was fast the way it was. Rest assured i was pleasantly surprised once I resolved this issue.

If your not getting full throttle then not only will you be slower due to the lack of air and gas entering the engine, but the WOT (wide open throttle) sensor will not click on and default to WOT fuel maps in the chip in the dme. You won't be driving at balls out performance.

+16 on loosing weight. That being said...
Let the guy continue to drag race his car...We need more posts on motor drops and clutch installs:p

Here is a great source for a turbo kit:

http://www.geocities.com/protomotive/products.html

I don't always street race the car, for all those people freaking out about it. It was one race I had with a buddy of mine just to see how fast my 3.2 was because i used to have a 350z, pretty much the only time i really raced my car on the street. I don't plan on going out picking street races so please relax.

I just want help on getting more power out of the car.

Thanks 911st for the link. If anyone else has any opinions on what to do I would like to hear them.

Not my cup of tea but I would think the 911 w g50 transmission dose have the makings of a good drag car having 60% of ones weight over the rear wheels.

A LSD would help.

For years the Porsche 930's and Turbos posted the fastest 0-60 and quarter mile times in the car mags.

It does... given the rear weight bias, the car hooks up and launches very quickly. There was a guy that professionally drag raced his 964 turbo in the 9sec range.. Mello - his name?

The 911 platform has successfully competed in every motor sport category beyond the common road course. From off-road dirt racing, rallies, hill climbs, land speed records, ice racing, endurance racing, and even drifting. I see drag racing as just another venue that it can compete with the best of them.

As for a faster 3.2 - replace it with a 3.6 :)

Do you REALLY want to make your 911 faster? Really? I mean do you really want to make it faster or are you just saying you want to make it faster? What I would do is sell it and buy a nicely modded 930, SERIOUSLY! Then make it what you want.