ZCAT3

What is the most effective way to increase 930 acceleration through gearing changes? I would appreciate cost estimates with any feedback. Thanks.

pig4bill

Well, there's the obvious: a G50/50. Looks like around 7 grand for parts, plus install labor, which I imagine would be 2 grand or more around here.

ZCAT3

Hey Bill - well I was hoping there was a way to perhaps just re-gear first gear for a better take off. I have actually grown to like the 4 speed. It is pretty nice for driving around town and at varied speeds. You can pretty much stay in 1st or 2nd for eveything you need.

FATTONY

For the best results, you should consider putting in new gear sets for first second and third gear. Then put your factory third gear into the forth gear spot. Your top speed will be limited to about 145 but the acceleration will be incredible.

ZCAT3

Fatto - what type of acceleration change are we talking about? If I can do 0-60 in 4.5 seconds now with a street start, what would I expect with a gearing change?

H20NOO

ZCAT3 - I have a couple questions regarding performance upgrades you made to your 993 Cab.

If you don't mind, send me an e-mail and I'll reply with some specific questions. I'm unable to send you an e-mail using the function on this board.

mconnolly@corp.address.com

Thanks,

MC

gavin11

Bill,

Steve Weiner has discussed gearing changes in the G50 to increase acceleration in the past. He has said it can make a significant improvement. You may want to drop him a line.

Good luck!

Peter Carroll/Toronto

I had a killer gearing change a couple of years ago when I went with a lower than stock tire size (profile)! If you factor in the fact that you'll probably need tires soon, it's free! The other bonus is it does a nice job of lowering the car while you're at it. You can do it in the transmission but it's a lot more expensive.

The down side is that first gear is a complete waste of time. Personally, I think 1st is too low as it is.

The problem with this technique is finding the right tires. I was running 275/35-17 rears. I really noticed it when I went to 275/40-17. I suspect it is a lot easier to find undersized tires with 15" rims...

The other thing I was considering was a ring and pinion change during my last rebuild. But again $$$$!

This is the car with the 35s:

pig4bill

I've discovered with Porsches, there's always "a way". It just depends on how much money you want to spend. :-)

My guess is that by the time you pay to have your tranny yanked, ripped open, swapping gear(s), put back together and back into your car, it will be a nice piece of change. Maybe not much less than doing a complete swap for a G50/50 considering you'd have your old 4 speed to sell. Yes, I know you're happy with your 4 speed around town. Decide after your next trip to Laguna Seca.

Luke

Absolutely BEAUTIFUL!!!

ZCAT3

Peter - could you explain your post to me? The stock rims for a 930 are 16 inches, so how did you increase acceleration with a 17 inch rim?

pig4bill

Get some 15 inchers with those 20-series tires that some of the Civics run. Maybe you can even find some that stick out past the fenders.

John from WA

ZCAT you don't increase acceleration. The overall tire/wheel combination size should still be the same (unless you do what they did on 935's with the extra big rear wheels). Anyhow Porsche hasn't change the overall tire size by more then a fraction of an inch since they started making cars.

The bigger rims may improve the cornering ability by limiting the amount of tire roll.

John
'79 930

ToyCollector

Original owner of my 930 had Andial put a 5:1 rear end in mine. Stock is around 4.1:1 I believe. Get's out of the hole real well and 1st gear is just a blur. Breaks loose going into 2nd when powershifting.

Peter Carroll/Toronto

Sorry I didn't explain fully. Stock rear size on a 930 is 225/50-16 or 245/45-16 for later cars. The "official" rear size for 17" rims is 255/40-17. Going by tire spec sheets, both have a height of about 634mm and a circumference of 634*PI=1992mm.

I now have 275/40-17 at 2023mm or 2% too tall gearing. I used to have 275/35-17 at 1961mm for 1% shorter gearing. I lost 3% of my gearing by going up a size. And believe it or not, it was quite noticeable. Not on the speedo (because that's affected as well), but in the seat of my pants.

Now, there's the theory. Now get some 15" wheels off a '77 930 and try on a set of 245/45-15s. That's 1890mm or 5% shorter gearing.

ToyCollector can probably justify replacing all the internal gears when he does his rebuild from too much powershifting.