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901 first gear weakness ; What will it sustain?

I posted this question before somewhere so I apologize if this is redundant.

I have a 914 901 with the collected conversion parts to flip the R;/P for a beetle. I'm planning on using 195/70/15 tires ,reinforcing the trans forks for beetle use and using a 1904 with a late spooling turbo.

My question is on the relative strength of first gear. If I were to basically street race .or launch as hard as possible just basically far enough to get the RPMs high enough to boost for when shifting to 2nd ,Is this too much for the 901? I don't want to do burn outs with it or let it wheel hop, just a hard launch prior to hitting 2nd gear.
Thanks for your expertise!
Any actual stories of what exactly broke your 901 is greatly appreciated.
Old 03-06-2018, 03:50 PM
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I would not recommend using the 901 for a drag racing transmission. 1st gear was originally designed to allow the 914s that road raced to go through the pits at a nice slow speed and not get into trouble. The 1st to 2nd shift is not great either as you have to go through the dog leg and the 901 transmission does not have the great synchros like a Mendeola transmission or similar. The road racers I raced with would usually swap the input shaft and use a 2nd gear which was higher but you still have the shift pattern. I just checked Rancho Transmissions and they have lots of choices.
Old 03-06-2018, 05:32 PM
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You can twist 1st gear off the mainsheet with the mighty ~85 lb-ft of torque that the 1.8 liter motor produces if you side-step the clutch. I wouldn't trust it with a boosted 1.9 liter...

I agree with John, get a trans that is made for your application. Even if you can live with the weak 1st gear, you're still having to beat up the trans tunnel in the Bug (or cut it up) and do a bunch of fabrication for the shift linkage. Far better to use something that really fits, and has been built to take the torque you want to put through it.

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Old 03-06-2018, 05:55 PM
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Thanks for the replies.

I changed my mind for my project and want about 200hp out of a 1904 type I.

I'm surprised that even with narrow tires on it ,it won't hold up.

It's a shame in a way because I have all the parts to the the swap, nose cone, shifter ,shift rod etcetera. I guess i'll try to sell it as a kit.

Last edited by Beetle_X; 03-06-2018 at 06:11 PM..
Old 03-06-2018, 06:09 PM
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If you're willing to just light up the tires, it should survive. We know people who have run 3.0 liter 911SC motors through the 901-style gearbox, but they were not launching hard. Rather, they were just lighting up the tires in 1st gear, or taking it easy to get into 2nd gear.

I actually know someone who run a 2.8 liter race motor through a 901-style box, and he wasn't exactly kind to it. But he did avoid shock-loading it in 1st gear. He was using it for road-race duty (tracks like Laguna Seca, Daytona, etc.) where the initial launch is not super critical.

Horses for courses; the 911's gearbox is designed more for road racing than drag racing.

--DD
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Old 03-07-2018, 10:07 AM
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I don't shock 1st gear but I do hammer it after it's in gear sometimes. It's handled my 3.0L nicely.
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Old 03-09-2018, 07:40 PM
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Years ago, I serviced a 10-second drag car that was originally built with a 911/00 4-spd .. essentially the same parts as 901 (but with standard H-pattern). After babying that turd for 6 months, I talked the owner into switching to a properly built 091/002 hybrid transaxle. Night & day difference. The VW trans required zero tinkering, and quarter-mile times dropped significantly with the Borg Warner synchronizer system.
Old 03-11-2018, 06:51 AM
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For your speed racing or any other stunts, you may put too much pressure on the vehicle. For the best results, it is better to consult the user manual of the same. And if you do not possess the user manual, now you can get a copy of it online on manuals.co at absolutely nil charges. Get your copy today.
Old 03-28-2018, 05:57 AM
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Geary alluded to it above, but if you really want to use the 901 box, a 4 speed is a better option strength-wise because the weak first gear is eliminated. First gear in a 4 speed is moved to the second gear position, and the smaller gear is integral with the mainshaft.

Scott
Old 03-28-2018, 08:13 AM
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