Advantages Of Double Synchromesh Gearbox?

[jhjones]

Whats the advantages of double synchromesh gearbox to a single synchromesh gearbox, assuming they are the same gearbox.

[GTSBoy]

Double sychros are harder to beat.

[jhjones]

You mean they are stronger or faster?

[GTSBoy]

I mean if you slam a fast gear change through with single synchros and get a crunch because you've managed to get the gear teeth to touch each other before the synchros have managed to match the speeds, then doing so on a double synchro will be harder. They also are "stronger" in that they will take such abuse for longer before wearing out.

cheers

[jhjones]

Ok, thanks. I'm actually trying to compare my RB20E box in my r33 to the RB20DET in r32s. I'm guessing an RB25DET with that box won't be ok.

[GTSBoy]

Don't try to run an RB20XXX box behind an RB25DET. The RB20DET box is essentially the same thing as the RB25DE. Pretty strong, but not able to handle the torque from a 25 turbo for too long. The RB25DET box is a big heavy bastard of a thing for a reason.

But looking at your other thread, you're asking if you can put a 25DET box behind an RB20E? Well, if that's the way you were asking in this thread too, then yes, it will fit up to the motor, but I don't know if the length is the same. You might need to find the mathcing front part of the tailshaft to go with it.

Edited June 23, 2011 by GTSBoy

[OMGGTR]

I dont beleive they are stronger, imho its just smoother transition into gears

[jhjones]

Don't try to run an RB20XXX box behind an RB25DET. The RB20DET box is essentially the same thing as the RB25DE. Pretty strong, but not able to handle the torque from a 25 turbo for too long. The RB25DET box is a big heavy bastard of a thing for a reason.

But looking at your other thread, you're asking if you can put a 25DET box behind an RB20E? Well, if that's the way you were asking in this thread too, then yes, it will fit up to the motor, but I don't know if the length is the same. You might need to find the mathcing front part of the tailshaft to go with it.

What I mean is will a 25det box fit in a 20e chassis without modifying stuff. Anyway I get it now.

Another is, is the clutch and flywheel different sizes?

I dont beleive they are stronger, imho its just smoother transition into gears

Can anyone else confirm this?

Edited June 23, 2011 by H4x

[wlspn]

What I mean is will a 25det box fit in a 20e chassis without modifying stuff. Anyway I get it now.

So your R33 currently has a RB20DE gearbox?

You should be able to fit an RB25DET box but may need to modify gearbox cross-member (very easy, ask via PM if unsure how) & would probably need to modify tailshaft for the bigger yoke needed for an RB25DET box.

Another is, is the clutch and flywheel different sizes?

Clutch & flywheel will be identical.

Can anyone else confirm this?

Yes, that's right. Although as the box will cope better with harsh shifts, etc it will seem stronger...

[R31Nismoid]

25DET boxes are much stronge than 20DET/DE boxes. You don't get 20-30kg difference from some extra syncs.