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 Post subject: Removing pinion gear?
PostPosted: December 30, 2021, 1:40 pm 
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Joined: September 22, 2005, 10:29 am
Posts: 599
So conceptualizing a mid-engined build here. I'd like to use a direct mechanical connection so as to eliminate the hassles of using a chain. I've got limited fore/aft space, so I'm considering rotating the motor to transverse configuration. My questions are:

-What is the HP gain by removing the extra bevel gear?
-Is it particularly difficult to remove said gear and add a coupling?
-Would there be a significant weight shift towards the drivers side which would unbalance the car?

All feedback appreciated.


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PostPosted: December 30, 2021, 3:39 pm 
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I'm a little confused by your terms.

There are two axles with a differential in the middle.

The diff can be driven by a sprocket via chain (transverse) or a ring gear via pinion (direct couple).

Consider a cush drive in between.

In general, parasitic loss is typically 15% for higher output machines and half that for transverse typical fwd machines without a bevel drive. Many factors go into the total loss.

Imho, the most compact overall in a side by side, rwd config build would be similar to ccrunners Berkley with the bike motor up front between the suspension bits and a long shaft. Make it a little wider so the diff and output can be centered and run parallel to the chassis in a tunnel between the seats.

A chain bec bolted to a bellhousing adapter with a custom adapter on the bec output shaft to support the input shaft pilot on a fwd transverse trans mounted in the rear would have a little bit longer wheelbase but would have roughly half the parasitic loss. The long axle on the fwd trans could be shortened for a narrower track and keep the struts but adapt for smaller od springs.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12


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PostPosted: December 30, 2021, 4:04 pm 
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Joined: September 22, 2005, 10:29 am
Posts: 599
OK, I see the confusion. My bad. almost all motorcycle engine's native configuration is transverse. So bike engines either have a sprocket or a bevel gear with shaft drive. What I'm proposing is taking a bike that came from the factory with shaft drive and either hooking straight from the shaft drive output to the diff (with a guibo) or removing the bevel gear and rotating the motor 90 degrees and then connecting to the diff via guibo.


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PostPosted: December 30, 2021, 4:30 pm 
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Better to start with a sprocket bec if going to a sprocket diff than using a shaft drive turned sideways which would require adaptation and will probably have chain clearance issues.

There are examples of both here. Check out John's build with a diy cush driving a diff. A standard guibo doesn't work since the driven sprocket must turn true all the time.

viewtopic.php?f=10&t=19392

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12


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