5 speed better or worse for a turbo engine.

[theKbStockpiler]

The title says it all. I have the parts to do a 914 5 speed conversion but was wondering if it might be a step in wrong direction. I hear that when big block owners go with a supercharger they actually prefer a 3 speed over 4 because of the broad torque curve. A turbo is generally stated as being best at boosting at higher RPM's though.

Thanks for your input.

[panel]

What's the ratios of the 4spd? And what ratios for the 5spd ?

[Clonebug]

The 914 5 speed is a slower shifting transmission.......which takes longer to get back on boost.

Ask Mario how fast my 67 trans will shift........

[theKbStockpiler]

Is it just to get it over the 1st/Reverse gate or overall?

Also the five speed is basically evenly spaced between gears If I remember right with final gear being the same as the 4 speed.

Here's the 5 speed specs. I'll post the 4 speed vw later.


Transmission type(s): 914 (300.01, 300.05, 300.11, 300.12)
Original equipment for: Porsche 914 70-72 w/tail shift or 73-76 w/side shift
Description: 5 speed H pattern manual transaxle with early Porsche synchromesh and dog leg 1st gear
Limited Slip Differential: A ZF 40-80% LSD was optional equipment
Speedometer: Mechanical
Transmission controls: Rod linkage
Clutch: Mechanical/cable, push clutch, 215mm single plate
Oil capacity: Approx 2.5L hypoid SAE 90
Weight: Approx 119lbs

Stock gear ratios:

1970-1976 914/4: 11:34 A, 18:34 F, 23:29 N, 27:25 V, 31:22 ZD Or approximately 3.09 1.89 1.26 .926 .71

Final drive 7:31 Or approximately 4.428

4 speed beetle

[madmike]

I luv the stock gear ratio in my 76 wouldn't want anything with a 4:42 or even a 4:12
wider the ratio the better for the load

[64 sunroof]

I used to have (still have in the workshop) a 901 5 speed in my beetle (same box as the 914 tail shift box but with the diff reversed) however i managed to break 1st twice with about 80 hp I had slightly different ratios when it was rebuild than a stock one, with my tyre size it was basically like a 1200 box 1-4 then a bit longer than a 1600 box in top was nice but not really very strong, although im sure if i was more careful it would have been better.

when it comes to racing i prefer longer gears to load the turbo up and have less gear changes, it really depends on the powerband you end up with on my drag golf i use a Diesel gearbox simply because i couldn't do the 1st gear change quickly enough to not mess it up every other time.

[theKbStockpiler]

I used to have (still have in the workshop) a 901 5 speed in my beetle (same box as the 914 tail shift box but with the diff reversed) however i managed to break 1st twice with about 80 hp

Were you dumping the clutch or just hard acceleration? How wide are your rear tires?

[woodsbuggy1]

I bet a 6 or 7 speed would be even better, the more time you spend shifting gears the less time you will be on boosts.
Sorry, don't mean to sound like a jerk but just look at what works for the guys that are serious and copy as much as you can.
Good Luck
Kenric

[Chip Birks]

I run a 4 speed in mine. No reason to run a 5 speed, it has more than enough get up and go to pull long gears. Mine are slightly shorter than stock, but i run a taller tire that stock too. The added cost of converting to anything Porsche makes very little sense in my mind.

[theKbStockpiler]

The 901 5 speed has a weak first gear but some people think it would be okay to do hard launches with 195 tires on it. I just did a thread on Pelican Parts and the respondents are telling me it's pretty easy to snap off the main shaft with even a 80hp motor. A new shaft is $1500.

I guess I will plan on shelving the 901 idea and let a 914 owner have a chance to break it up instead of me. I liked the way my old 74 ;with a 4 speed ,drove around town anyways.

[petew]

901s would be starting to be valuable with the concourse Porsche crowd wouldn't they? I'd sell it off and buy a Subaru if you really want a 5 speed. But like most people here, the stocker late AB trans are my pick. Just make sure you go with a 3:88 R&P. Wish I'd done that now.

[buguy]

I bet 3:88's would be great! My stock 65 first gear is useless! I can let the clutch out with no gas input without stalling.... easy. Even before the turbo. It would be a great car to learn to drive a stick in!

[theKbStockpiler]

The low 1st is a blessing to get going on a hill.

[buguy]

I live in Florida. Dead flat here.

[woodsbuggy1]

Indiana is flatland too. The first time my buddy from Kentucky came up visit he said "If your dog runs away you can watch it for 3 days" . I guess that why we go south and east to climb hills.
Kenric