Any experience with straight cut gears in a 914?, I'm thinking about it when I do the scooby swap. Options

[Jeroen]

Why not use the Subaru gearbox. It is a much better design than the shitty old 901.

Why waste the extra money on the Subaru gearbox when, as you said above, I'm going to be looking in my rearview the entire time anyway?

because with the Suby box you'd end up in a different class, where you'd be less of a moving chicane

[Brad Roberts]

OK.. I dont care where he is going to run or with who.

Somebody explain to me why people are not using the Suby box in a 914?

Use the output for the rear diff to drive a prop or something (JK)

This would eliminate adapters/special clutch.. blah blah..



B

[Aaron Cox]

they (the suby guys) are working on it...

rear drive block off.. and CV adapters/output flanges to work with 914/911 cv's

[So.Cal.914]

Never said I had to win. I'd just enjoy the race. I used to stoplight race my bug against cars that I stood absolutely no chance against; like a GT2 and a 360 Modena. Knowing I wouldn't win didn't make it any less fun.

I don't know you but asking about square cut's leads me to believe that you

are looking for an advantage. A winner also wants an advantage, even an

unfair advantage. You may be happy with second best for a little while but

eventualy you will want to win. IMHO.

[Rider914]

Why not use the Subaru gearbox. It is a much better design than the shitty old 901.

Why waste the extra money on the Subaru gearbox when, as you said above, I'm going to be looking in my rearview the entire time anyway?

because with the Suby box you'd end up in a different class, where you'd be less of a moving chicane

Would the Subaru engine not change his class? Is it the same displacement?

[xitspd]

We use quick change Sprint Car straight cut gear, rear ends in the sand toys we fabricate. VERY LOUD AT SPEED!!!!!!!!!!!!!!!!

Dan

[Dr Evil]

All of the Hewland and MK5 gear sets are based on the same pinion and input shaft spacing as our 914/901 boxes.

Our tranny is a glorified VW box.

Can he do it? Yes. Will it take some potential special parts? Yes.

Benefit on the street? None.

Benefit for racing? Lift throttle clutchless upshift (or full throttle depending on how often you want to replace the gears) or ignition interupt upshift.


B

Hey B, looks like a good time for me to learn something. How does a tranny with constantly meshed gears (our 901) shift different with straight gears (clutchless upshift)?

Also, why would the straight cut gears be considered stronger as mentioned above? The curved gears have more surface area for strength and load/stress dispersion, I would think.

(IMG:style_emoticons/default/popcorn[1].gif)

[blabla914]

I guess this is sort of a thread hi-jack, but the suby swap has so much potential.

I also do not understand why people are not using the suby trans. I saw the thread about the Aussie block off plate. That seems like a plan. Couldn't you just leave the shaft haning out the back? Like Brad said "drive a prop or something". What are the specific issues? How complicated is the block off plate?

Why make adapter plates to use Porsche CV's on the tranny side? Seems like what's his face (I can't remember the vendor) who will custom make hollow axles could spline some for you Porsche on one end (944 turbo would be a good pick) and suby on the other. I looked into hollow axles a while ago and I recall the price for a set of axles was like $400. Depending on the cost of suby CV's vs Porsche CV's might come out the same $$ as adapter flanges and be lighter.


Kelly

[brp914]

the benifit of helical gears is they are quiet. the drawback is, part of the force is trying to shove the gear off its axis causing stress and wasted effort as the driven gear is forced against a thrust bearing. recall your trig.

[guiltless]

Quick clarification... shifting has NOTHING to do with the gears being straight or helical cut. Shifting is determined by the engagement style. Synchro, standard clutched shifting; and Dog, clutchless upshifting and heel-toe downshifting.
Gearsets for a Sooby run in the $4k-$7k range depending on cut and engagement from PPG. the box itself can be had for a few hundred.

[RockinOldSchool]

I don't know you but asking about square cut's leads me to believe that you

are looking for an advantage. A winner also wants an advantage, even an

unfair advantage. You may be happy with second best for a little while but

eventualy you will want to win. IMHO.

Not so much an advantage as just looking for better performance. The better my car performs, the more I enjoy driving it.

Also, why would the straight cut gears be considered stronger as mentioned above? The curved gears have more surface area for strength and load/stress dispersion, I would think.
(IMG:style_emoticons/default/popcorn[1].gif)

Actually due to the straight angle of the straight cut gears they have more surface area in contact at any given point than a helical setup will. Making it less likely to fail under the force. On a helical setup the contact patch rolls across the tooth rather than being in complete contact the whole time. Which makes it have a smaller contact surface area.

[Jeroen]

suby engine and box in mid engined config
(IMG:http://64.82.22.49/galleries/TheCar/images/DSC_3485.jpg)

coverplate
(IMG:http://64.82.22.49/galleries/TheCar/images/DSC_3540.jpg)

check: http://64.82.22.49/default.asp

[Dr Evil]

Thanks for the info guys. I knew the straight cut gears had no difference on shifting (I have only rebuilt over 100 trannies (IMG:style_emoticons/default/wink.gif) ) I was just wondering if I missed something. That was a few good explanations of why helical and straight differ in action. Thanks. (IMG:style_emoticons/default/thumb3d.gif)