VR6 in a T25

[Natyb]

Hi Dubbers.
Im planning to fit a golf VR6 engine into my Transporter T25, I have a mechanic that knows both the van and engine, wanted to know if any of you have any tech support or pointers to assist??????????????

[g60steve]

It's been mentioned on here a few times.
Have a search or Google VW T25 VR6 and Vanagon VR6.

To get the best from the engine it's a good idea to fit a modified gearbox as well.

[slobbo]

No need for anything special in the gearbox. The 2.1 gearbox is plenty strong enough for a stock VR6. The torque curve is very similar to the 2.1 just higher up. I had to get my gearbox rebuilt but it wasn't necessarily because of the VR6. I should have put in a slightly taller 4th for motorway cruising (mine is a Syncro so 4th is top).

It is a lovely engine well suited to the van however it is slightly thirstier than the 2.1 but not by much I can get 20mpg driven sensibly. I reckon you could get better than that in a 2wd.

I am considering getting mine converted to OBD2. Maybe even swapping in the 2.8 20 valve from the T4 caravelle for smoothness and the on board diagnostics. Not really needed. More just because I can. You've got to waste your money on something after all.

[g60steve]

No need for anything special in the gearbox. The 2.1 gearbox is plenty strong enough for a stock VR6. The torque curve is very similar to the 2.1 just higher up. I had to get my gearbox rebuilt but it wasn't necessarily because of the VR6. I should have put in a slightly taller 4th for motorway cruising (mine is a Syncro so 4th is top).

I doubt a standard,well used 5 speed box would last long with 175+bhp running through it without it being rebuilt.

VW didn't use a standard 5 speed 'box on the 5 cylinder 2.5i & 2.6i South African vans and they were "only" approx 135bhp.

When I had a VR6 Bluestar the gearbox had been rebuilt to match the gear ratios of the donor Golf....hence why I stated "modifed" gearbox.
Naturally because of those modified gear ratios it drove as intended rather than 1st being totally useless and revving it's gonads off at motorway speeds.....like most non T25 engines do when mated to a 5 speed gearbox.

[slobbo]

MIne is - Gearbox is an AAN with a 4.86 final drive. Manufactured on 10/12/85 (early box). 0.85 4th Gear ratio. Rebuilt by Aidan Talbot July 2010.
- Front Diff is an ADH

When Aidan and I reviewed the data it didn't appear to need anything different from the stock 2.1 Syncro gearbox (which is exactly what it was). In operation my engine revs slightly higher than I would like at 70 MPH but not excessively. I would prefer is sitting at about 200rpm lower than it does in top.

My wheels and tyres are bigger by 8% so that will be making a difference as well.

It isn't the BHP that is the problem it is the torque and a T25 gearbox in reasonable order shouldn't have a problem with the 235–265 N·m (173–195 lb·ft) of torque the Golf 2.8 produces.

[Aidan]

Rob also has the oiling plates fitted as per the SA vans, which was the only real difference between the european spec boxes and the SA 5 pot ones, they were all made in Germany afaics
Big wheel syncro like Rob's different to a 2wd, maybe we should have gone 0.82 top really, that was Rob's call, I couldn't say definatly that it would be better, he had driven the van with the engine and gearbox combo, I hadn't; box needed a rebuild anyway, we thought maybe it had been modified previously, but it turned out it hadn't been
2wd bus I'd go with the 4.14 c and p as per Steve's bus, and oiling plates
but I'd advise doing the conversion first and driving the van before making a decision about the gearing

[syncroandy]

I doubt a standard,well used 5 speed box would last long with 175+bhp running through it without it being rebuilt.

Probably sound advice, though the standard AAN in my EJ25 kombi has held up fine for ~4 years. It was cheap so I thought 'what the hell I'll chuck it in and see'. I did however get the longer/stronger gears for my TDI. Some numbers:

Various petrols

2.1 WBX (DJ) 112bhp / 127 Nm
2.5 EJ25 165bhp / 226 Nm (167 ft·lb)
1.8 G60 (PG) 158bhp / 225 Nm (166 ft lb)
2.9 VR6 (ABV) 190bhp / 245 Nm (181 ft lb)

TDI Engines

1.9 1Z,AHU 90bhp / 202 Nm (149 ft lb)
1.9 AFN 110bhp / 235 Nm (173 ft lb)

PD Engines

1.9 AWX 130bhp / 285 Nm (210 ft lb)
1.9 AVF 130bhp / 310 Nm (229 ft lb)
1.9 ARL 150bhp / 320 Nm (236 ft lb)

[g60steve]

1.8 G60 (PG) 148bhp / 225 Nm (166 ft lb)

158bhp Andy.

[syncroandy]

Darn, I think some of that data came from Wikipedia.. I just checked ETKA it shows the PG 118kW, 160bhp.

[slobbo]

Ok so are you guys saying to strip a perfectly working box with the correct gearing for a given engine just because it MIGHT be worn. I have had 2 boxes rebuilt. 1 to change the gearing for a TDI (yes this is the right reason) and the second because it was broke. Both rebuilds cost me considerable wonga so advising people to rebuild a gearbox because it "might" be worn is daft in my book. These boxes are built to last and whilst they do wear it takes poor maintenance and/or many miles.

[syncroandy]

VR6 electrics should be interesting too..

If I were putting in a mid-90's VAG motor and wanted to make a proper job, I'd be tempted to upgrade CE1 -> CE2. Anyone done this ?

[g60steve]

Ok so are you guys saying to strip a perfectly working box with the correct gearing for a given engine just because it MIGHT be worn. .

But the gearing on any T25 isn't correct for a VR6 engine.
By using a standard 5 speed T25 'box with a VR6 1st gear would be redundant....it almost is just with a 2.1 WBX.....and at motorway speeds it would be revving higher than when in the donor vehicle.

You even state yourself that your engine revs higher than you'd like and that's even with a 8% increase in tyre size.

[g60steve]

Darn, I think some of that data came from Wikipedia.. I just checked ETKA it shows the PG 118kW, 160bhp.

ETKA is incorrect as well if it states bhp rather than ps....118kw = 158bhp
118kw = 160ps.

[ewenmaclean]

If I were putting in a mid-90's VAG motor and wanted to make a proper job, I'd be tempted to upgrade CE1 -> CE2. Anyone done this ?

if anyone's going to do a proper job of it you are - I looked into this for about 30 seconds and ran away with a headache - it would be a brilliant thing to do for a vag engine transplant, but a fair bit of work I reckon...

[syncroandy]

Heh, funnily enough I've been looking at it this afternoon ! Got a harness conversion job out of the way and was having a tinker with one or two of my projects.

I just got a nice TDI 3A Passat dash panel with MFA off Ebay and I'm inclined to use this instead of the 3B one for several reasons. Also have some early T4 stalks with MFA and CCS, which of course are CE2 pattern. You can probably see where I'm going with this.. The dash panel is connected by one neat harness straight into the back of the CE2 relay plate where it picks up all the signals it needs.

I think I'll start off making up a big list of all the connections with the T3 and Golf Mk3 wiring diagrams in front of me and try to plan out the mapping CE1->CE2. In principle it should be as simple as swapping the connections coming into the back of the T3 relay plate onto the correct pins on the CE2 connectors.