MPG.

[The BCE]

Hello,

I bought the galvanised syncro that was advertised on here. Was just puzzling over what to do about the wheels on it and possible impact on mpg.

I will be using the van for my daily drive to work and back (6 miles each way on winding Cornish lanes) and then trips away - to include field based camping and festivals. Getting stuck for 7 hours in mud last year and having to be pulled out by tractor was the reason for getting a syncro in the first place.

Van has a 2.9i VR6 Corrado engine in, which I think I have probably been over-revving according to this thread! (Does move quickly though if you want it to )

According to the handwritten notes from Jean-Louis Brion that came with it (and assuming that I'm reading his handwriting properly!) the rims are Mercedes 8 x 16. Tyres currently on it are Bridgestone Dueler M/T LT225/75R16.

I'm thinking that the fuel economy from these can't be as good as if I fitted an all terrain tyre?!?

The van is a 14", but with adapted suspension to accommodate the 16" wheels. Have considered putting it on to 15" rims to make it look slightly less beefy (my wife isn't totally happy about this aspect!!) and make it easier for the kids to get in and out!! Also tyres could do with being slightly less wide as the sliding door is snagging on the tyre despite having a spacer fitted.

Would appreciate advice on wheels/tyres and impact on mpg.

Haven't got enough figures to work out consistent mpg figures and I'm experimenting with revs etc. Also speedo etc. out (previous owner thinks actual speed +10% from sppedo) and don't yet own a sat nav.

Thanks to Rob for all the advice,

Cheers,

Ben

[syncrosimon]

Contgrats on your purchase.

Had a T4 VR6... wow what a vehicle... I really do regret selling it... compared to the T4 tdi it was just a revelation of comfortable travel. The effortless power was just beautiful, to have that in a T3 syncro must be a delight.

On the mpg front, I would say that the tyre choice is going to effect mpg more through gearing than through what sort tread you have. If it were mine I would put the VW steel wheel 5 1/2J x 16" on as alloys are so common now steel wheels are more exotic!!

What rpm are you pulling at 70 mph, have to take her around the Bodmin Bypass and see where you are, if the engine is over revving then that is where the fuel is going. Diesels are able with all their add on's to squeeze more fuel into one cycle of the engine producing more torque low down, and pull lower revs at speed, gaining economy.

Thinking back my VR6 did around 21mpg average, about the same as a wbx, but twice the power!!and in some ways twice the fun, I love big petrol engines, they make you smile, smiles cost pounds though.

Simon.

[Aidan]

last years fuel figures for Beaker saw lpg at 12.53ppm over 6k miles, and I reckon about 18.5ppm on petrol so you need to be doing something over 8k miles per annum and keep the vehicle a good few years to make lpging it effective, £900+ buys a lot of fuel. And the tank takes a lot of space and adds to weight and thus cost of running vehicle.
I don't believe anyone who says they are getting better than 20mpg on lpg, especially not the way some of them drive.
No brainer for me to swap over the lpg kit from the mustard pot as it had long gone into payback time and the cost of tranferring it only cost about 3 months fuel so a year later it was back in cheaper running costs overall and now this is my only vehicle it means I can still afford to use it, though fuel is still the biggest cost even allowing for upgrades and rebuilds and repairs.

[HarryMann]

The van is a 14", but with adapted suspension to accommodate the 16" wheels. Have considered putting it on to 15" rims to make it look slightly less beefy (my wife isn't totally happy about this aspect!!) and make it easier for the kids to get in and out!! Also tyres could do with being slightly less wide as the sliding door is snagging on the tyre despite having a spacer fitted.

Ben,

I saw this galv syncro when he first brought it to Vanfest (and wanted £5.5k not to take it back to Belgium), they same year Terry sold his for £10k

I thought the exact same thing, great vehicle ruined by inappropriate wheels, tyres and jacking up...

One thing he did say to me, was that the exhaust system was far from optimum, it's tuned length was too short and therefore biased towards the higher rpm band.

The inertia of those wheels alone would make urban and short trips a bit more juicy I'd imagine... but know little about the torque band and gearing that you have... maybe talk to pete Morril about the geraing and revs/mile of his Subaru 3.3 6 ?

[HarryMann]

[rswestling]

In keeping with the general direction of this thread...

Let's say you want to increase motorway mpg. What if you did the following to your basically stock 2.1 T25 doka with 14" wheels running standard size BF AT's:

1. go to 15" wheels (I already have them, just have not decided what to shod them with yet)
2. go to a more standard road tyre, like Conti Vanco 2's, with a greater diameter
3. install a decoupler for motorway driving
4. upgear a bit to match the tyre size

I'm just curious if these things together might not help. My son and I recently took a road trip through France and Germany of about 1300 miles and we got an average of 22.5 mpg cruising at 65 mph (according to the GPS). I've now fixed a hardtop over the load bay, and this actually has seemed to help, but this might just be my wishing that it was helping.

Thanks for any input,

Robert

[HarryMann]

I've now fixed a hardtop over the load bay, and this actually has seemed to help, but this might just be my wishing that it was helping.

Yes, that will help a bit...

Not sure what you mean by upgearing to suit the larger wheels, you mean a lower diff ratio to get the same miles per revs.. if so, what's the point?

[Syncro G]

This wheel weight issue has got me thinking so I got the scales out and went looking for wheels that wern't on a vehicle. I measured them on a mecanical bathroom scales, readable to about 1kg and by no means super accurate. Did thr first couple by difference with me and also on their own, didn't seem to make a difference so I did the rest on their own. Everytime I weighted myself and it came out about the same too so they seemed to be consistant and always on smooth surface - thats the fair test bit over...

1) BFG AT 27x8.50R14, 11mm tread on 6J14 = 24kg
2) Goodyear Xtra Grip 7.50-16, <2mm tread on 5.5F16 (tubed) = 26kg
3) Goodyear Wrangler m+s 7.50R16, 3...4mm tread on 5.5F16 (tubed) = 27kg
4) 5.5F16 rim only = 12kg (by difference)
5) Goodyear Xtra grip 6.50-16 tyre only = 11kg (by difference)
6) Colway 205R16 (retread), 5...9mm on 5.0F16 (tubed) = 29kg
7) unknown m+s 205R16 spare, 4mm tread on 5.0R16 (tubed) = 26kg
BFG Trac Edge 7.50R16, 3...4mm on 5.5F16 (tubed) = 31kg

Things I find surprising is how heavy the colway retreads and the BFG tracedges seem to be, good few kg more than other simular sizes.

I switched from 6 to 8 on my landy, its rased the gearing by nearly 10% as you'd expect but there hasn't been a noticeable drop in mpg on the unaltered odometer unless the tank was mainly used in hilly areas, whereby I woultn't say it was 10% worse than the colways so is therefore a saving. They've really killed its acceleration (gearing) but when up to speed it holds it quite well, handleing is poorer though - seems like those 2kg a tyre is quite noticeable (Big squiggy sidewalls don't help the handleing eather so its hard to pin the cause on weight or tread, it is much worse than the colways though! I think what I'm gonna do next is try the Wranglers to see if I notice the difference with significantly lighter wheels without gearing change, and what it does to mpg, though if I do that I think my dad will cut up the trac edges to make a garden path.

I've heard lower profile tyres past a cirtain ratio can actully weigh equal or more than higher profile ones as the sidewalls need more reinforcement (though I wouldn't have thought the high aspect ratios we use will be in that region, that said it mught explan why BFGs are so heavy?) so bigger rims for the same dia might not save much weight. Rims won't make as much difference as tyres as they are closer to the axis, remember the spacers if used on alloys - Alloys are in theory lighter but I doubt by much, they are usally done for style rather than weight saving (except for the mega expencive performance magnesium types on track cars).

Anyone else want to weigh their spare to see how they comare?

Is it possable to run a vacuum guage on a petrol syncro? Should be doable on a carb engine but not sure about the injection models. Might help keep an eye on how much load its under.

[HarryMann]

Vac gauge was always a useful consumtpion tool, although intuition based on speed, gradient and throttle setings is as good once you 'get' the idea...

Worthwhile data there Glen. It's the wheel and tyre inertias we should ideally be measuring, 2nd Moment of Mass, so they'd need to be suspended on axle and accelerated, using a given torque to determine that experimentally. However, one can deduce the MoI to some extent from the size and weight

[syncropaddy]

My God Clive..... you're talking about the stuff I used to do in Uni .........

Bigger wheels and tyres = more unsprung weight + bigger flywheel effect = need bigger brakes = more unsprung weight = heavier van = uses more fuel = I've got a headache ............

[HarryMann]

I suppose bigger wheels also throw more air about too Andrew!

[syncrosimon]

Anyone else want to weigh their spare to see how they comare?

26kg for a standard VW 5.5J 16 with 205 R 16 Nokian Hakkapellitta C2 tyer.

[The BCE]

The van is a 14", but with adapted suspension to accommodate the 16" wheels. Have considered putting it on to 15" rims to make it look slightly less beefy (my wife isn't totally happy about this aspect!!) and make it easier for the kids to get in and out!! Also tyres could do with being slightly less wide as the sliding door is snagging on the tyre despite having a spacer fitted.

Ben,

I saw this galv syncro when he first brought it to Vanfest (and wanted £5.5k not to take it back to Belgium), they same year Terry sold his for £10k

I thought the exact same thing, great vehicle ruined by inappropriate wheels, tyres and jacking up...

One thing he did say to me, was that the exhaust system was far from optimum, it's tuned length was too short and therefore biased towards the higher rpm band.

The inertia of those wheels alone would make urban and short trips a bit more juicy I'd imagine... but know little about the torque band and gearing that you have... maybe talk to pete Morril about the geraing and revs/mile of his Subaru 3.3 6 ?

I now have what I think is Terry's old van - will see what mpg I get from it!

[HarryMann]

OK, 25 mpg tops I reckon.

Has it still got that bullbar and front-spare on it?

[The BCE]

It has - I was debating what to do with that. Like the look of it, but not sure about ground clearance - although looked alright in the Diamong Isle 2004 pictures. Probably not helping mpg though!