Gearbox Ratio/RPM - Subaru Conversion

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matt brighton
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Gearbox Ratio/RPM - Subaru Conversion

Post by matt brighton »

Im pondering the likely rpm and driveabilityof my van with the 2.0L subaru engine fitted to my DM code gearbox - its an early diesel .

Im going to have to get a better suited (Adian recommends a DK) gearbox ........but have to live with what I have for time being till funds recover

I have been running big 225/80/14 tyres for a few years now - and by my failed cse maths works out at 3800rpm @70mph.

On the RJES gearbox page - on Richards colour coded low to high revving "gauge o meter" its high side of middle .... so I'm hoping it won't be too bad...... any experience with similar ?

On + side it'll get up hills and to 60mph quickly ?

Thanks for sharing any experience or knowledge


Matt

multisi
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Re: Gearbox Ratio/RPM - Subaru Conversion

Post by multisi »

Perhaps if you spend your available funds on a DK gearbox before buying the RJES parts , then while you wait in the queue for getting the loom converted you can save up and complete the kit. Im a big fan of the DK box, good ratios .What wheels do you have on your van, are they the original 14 steel wheels ?
1992 red lle 2.2 subaru 1990 rhd caravelle 2.2 subaru 1986 california import vanagon

matt brighton
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Re: Gearbox Ratio/RPM - Subaru Conversion

Post by matt brighton »

Yes 14" steels

It'll be a long time a savin ..... Im gonna get the engine in for now, - and make do with my" revvy" box for time being.


Brighton's very hilly and I don't plan any distance motorway driving at all or on autobahns or touring europe for next 12 months. I average less than 2000 miles a year in the van and I have an additional car this year so probably less over next 12 months

Thanks for reply and advice - good to hear from someone who's got the t shirt so to speak

I appreciate you giving my questions your time to reply

Best

Matt

matt brighton
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Re: Gearbox Ratio/RPM - Subaru Conversion

Post by matt brighton »

I have been rechecking and looking on the gearbox page for RJES

if my calculations are correct and based on my DM gearbox with 225/80/14 tyres i will be getting 3800 rpm @ 70 mph

Thats "only" 300 rpm more than the subaru legacy revs at same speed - so maybe my box won't be so bad as I thought ?

I will get a DK or similar in the long run though

Thanks

Matt

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937carrera
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Re: Gearbox Ratio/RPM - Subaru Conversion

Post by 937carrera »

Matt,

There's more info on the ratios here http://vwt3.com/t3-tech/t3-data/t3-gearbox-codes/

I have a spreadsheet which has a number of T25 boxes pre completed, I dropped in the changed top gear and final drive for the DM box and your 225/80 tyres and came up with 3864 rpm for the DM and 3142 rpm for the DK.

To double check that, DM revs * 4th gear ratios * final drive ratios = DK revs, so for 70 mph 3864 * .852 /.823 * 4.571 / 5.43 = 3142 rpm

Putting it simply, DK has a 3.5% longer 4th gear and a 18.8% longer final drive

Hope that helps
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

matt brighton
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Location: brighton innit

Re: Gearbox Ratio/RPM - Subaru Conversion

Post by matt brighton »

Very helpful - and thank you.

Im a bit reassured that my DM will only be 300rpm at 70mph more than it would be on its proper subaru gearbox

However 3100 at 70 sounds much more relaxed... anyone got a working DK taking up valuable room in the garage ?????

:ok

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