SR20 Transmission upgrade?

H

Hypnotik

New Member
I searched and didn't find anything so here is my question.

Eventually I'm going with a bigger turbine, I'm aiming for around 500whp. Right now I have a TD06-20G and around 380whp on a S14 5-speed. I'm basically at the breaking point of my transmission especially with some sticky tires on it. My question is, what is my best option to upgrade the transmission?

Options available to my knowledge;
-RB25DET transmission with the bellhousing cut off and SR bellhousing rewelded in it's place.
-VQ30 transmission with an adapter plate from Mazworx
-OS Giken gearset in the stock transmission
-Full OS Giken or HKS "crossmission" or "dogbox"

Is there anything that I'm missing or don't know about?

I'm leaning toward the RB25 transmission mainly because it is the cheapest option but would need a competent welder to make sure it is aligned and welded correctly. I've heard that the OS Giken gearset is not even as strong as the RB transmission and the OS crossmission is just way overkill for a daily driver.

Thoughts?
 
Most popular is the GTST box,contact polo or garage D,they will do a full conversion for you,or will supply a conversion plate and prop,no welding needed,these gearboxes happily run 400-500 bhp :thumbs:
 
Have a look at the quaife website they do complete box rebuild kits which only uses the original front/rear casings....everything else is replaced...centre yolk, shifter rods,shafts,gears, the lot, prop needs shortening to allow for the larger centre yolk, they are available in 5 or 6speed , dog,sequential,etc and they are made in UK , so parts are easily got and advice close to hand.....start at about £3k , not cheap....nice bit of kit tho, im after one soon.



QKE6F5 -
Nissan Silvia 5-speed dog engagement H pattern Quaife gearkit
Nissan Silvia 5-speed dog engagement H pattern Quaife gearkit.
Complete 5-speed dog engagement gearkit with 1:1 top
Straight cut, close ratio Comprehensive kits - includes selectors and gear lever.


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QKE7F5 -
Nissan Silvia 5-speed dog engagement sequential Quaife gearkit
Nissan Silvia 5-speed dog engagement sequential Quaife gearkit.
Complete 5-speed dog engagement gearkit with 0.790 top gear. Straight cut, close ratio, comprehensive kits - includes selectors and gear lever. Sequential gearchange


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QKE6F6 -
Nissan Silvia 6-speed dog engagement H pattern Quaife gearkit



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Prices from: £3,900+vat






QKE7F6 -
Nissan Silvia 6-speed dog engagement sequential Quaife gearkit
Nissan Silvia 6-speed dog engagement sequential Quaife gearkit
Complete 6-speed dog engagement gearkit with 0.790 top gear. Straight cut, close ratio, comprehensive kits - includes selectors and gear lever. Sequential gearchange


View details
Prices from: £4,995+vat
 
I'm very interested in the Garage D kit, I've never seen an adapter plate that didn't require machine work. I think I'm just gonna pick up a RB25 transmission and install it once I get to Italy.
 
I think going for the cheap option here is false economy, because you will break an RB25 or VG30 box at some point. Over here so many people are breaking them that prices are getting silly.

Some friends of mine have an RB20 powered S13 (grip) racecar pushing 300kW (400hp) at the wheels, after getting sick of breaking expensive RB25 gearboxes they ended up getting a second hand Jericho 5speed dog box from the states - cost was under $3k nz (about 1200 sterling?) shipping would be expensive unless you can get it added to someone elses container.

Obviously this option requires a plate to mate gearbox to engine, as well as new clutch plates to suit the input shaft.
But you'll never ever break it. (drag cars with 900+ hp and foot wide slicks don't even break them!)

IMO it's the only way to go for a car that is driven hard, synchromesh boxes are really best left for driving to the shops.
 
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