T3 Engine Upgrades - Gearbox ratios for TDI (ahu) syncro

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Gearbox ratios for TDI (ahu) syncro

Printed From: The Brick-yard
Category: T3 Section
Forum Name: T3 Engine Upgrades
Forum Description: Forum for tuned or alternative engines.
URL: http://www.brick-yard.co.uk/forum/forum_posts.asp?TID=93115
Printed Date: 24 Apr 24 at 09:06
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com

Topic: Gearbox ratios for TDI (ahu) syncro

Posted By: smokeyjon
Subject: Gearbox ratios for TDI (ahu) syncro
Date Posted: 09 Nov 17 at 20:32

Hi all
Aiden is currently rebuilding me a gearbox for me to use with an AHU (90BHP TDI). I drive a panel Van converted into a camper and tend to use the van mainly for holidays involving motorway travel and coastal roads.

I'd like to go for longest gear ratios for fuel economy (5.43 final drive; 1.09/0.70 3rd and 4th) but a few people have queried how drivable it'll be and suggested I go lower ( 3rd available in 1.14 and 1.18 versions and 4th in 0.73, 0.75 and 0.77 ). Aidan says this is pretty much his standard TDI box 'so it'll probably be fine' (although he thinks he'd probably go lower). Tyres are 215/70 16s.

Does anyone on here have experience of driving with these ratios who could advise? Thanks

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Still working (fingers crossed)...

AAZ Syncro Panel Van...

Replies:

Posted By: VW Nerd
Date Posted: 21 Feb 18 at 11:40

What ratios did you go for with your syncro in the end?
I also run an AHU with an Aidan Talbot gearbox rebuild. I'll have to check my ratios but I do find that I have to rev up to about 3000 rpm for motorway driving which seems far to high for my liking.
I'm also in Bristol.

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Developing parts for the VW T3 TDI market Inc flipped audi gearbox install parts.

Tim Shettle
www.ultimate-engineering.co.uk
Bristol

Tel/txt 07810 320 464

AFN TDI Panel Van

Posted By: smokeyjon
Date Posted: 23 Feb 18 at 15:28

It's not been done yet (busy with a house extension so the van keeps getting bumped!) if u could find out what ratios you've got I'd be interested to hear...

How do u find it between 2nd and 3rd? I'm worried that'll be a big leap at that point, and also that I won't have enough power up motorway hills in 4th.

I'm in plymouth now. Moved from bristol 4 years ago. I miss it a lot though it's a great city!

Look fwd to hearing back from u

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Still working (fingers crossed)...

AAZ Syncro Panel Van...

Posted By: VW Nerd
Date Posted: 24 Feb 18 at 14:37

I have the taller 2nd gear that came standard on later syncro gearboxes. On top of that I have the Weddle 1.09 and 0.70 3rs and 4th gears. 5.43:1 final drive. For tyres I run 215/70/16

I have yet to put all of this into a gear ration calculator. I'll make that my next job.

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Developing parts for the VW T3 TDI market Inc flipped audi gearbox install parts.

Tim Shettle
www.ultimate-engineering.co.uk
Bristol

Tel/txt 07810 320 464

AFN TDI Panel Van

Posted By: smokeyjon
Date Posted: 03 Mar 18 at 19:18

Thanks I'll compare that to my suggested ratios. I asked Marion for a TDI install quote today (not getting round to it myself!) and he was going to suggest some ratios do it'll be interesting to see what he suggests.

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Still working (fingers crossed)...

AAZ Syncro Panel Van...

Posted By: VW Nerd
Date Posted: 05 Mar 18 at 11:06

With 215/70/16 tyres I get 65.4 @ 3000 rpm

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Developing parts for the VW T3 TDI market Inc flipped audi gearbox install parts.

Tim Shettle
www.ultimate-engineering.co.uk
Bristol

Tel/txt 07810 320 464

AFN TDI Panel Van

Posted By: smokeyjon
Date Posted: 05 Mar 18 at 23:16

So what you seem to be saying is that you'd like the ratios to be higher if anything (but u have the highest available). Do you have any problems with being underpowered on hills etc? Do u have any mods to get more bhp out of the van, and is a fully loaded heavy camper or something lighter? Cheers

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Still working (fingers crossed)...

AAZ Syncro Panel Van...