Bongo Fury

Just wanted to see what RPM your diesel Bongos do on the motorway.

I know it's an auto, but it does rev quite high 2,500rpm = 60mph (ish) I think. Compared to my 6 speed car, which would be doing 80mph+ at 2,500rpm ! As the Bongo has quite a torquey engine, you'd have thought it could pull a higher gear ratio.

No wonder the fuel economy is poor.

Also, the turbo hiss is noticeable most of the time. I guess that beng a small turbo, it is desgined to simply supplement the engine all the time rather than give a noticeable "kick" like other turbo cars.

Just interested in other people's engine dynamics !

You wont get any 'kick' from a Bongo turbo as its running pretty much all the time as you've noted. The gearing on the V6 seems to be slightly higher than the diesel: I seem to recall that 3000 RPM = 69 MPH, but with a petrol, all the power is at the top end. It could definitely do with another gear in there somewhere to bring the revs down a bit.

Gripped wrote:Just wanted to see what RPM your diesel Bongos do on the motorway.
I know it's an auto, but it does rev quite high 2,500rpm = 60mph (ish) I think. Compared to my 6 speed car, which would be doing 80mph+ at 2,500rpm ! As the Bongo has quite a torquey engine, you'd have thought it could pull a higher gear ratio.
No wonder the fuel economy is poor.

How many "6 speed cars" are the same size, shape and weight as a Bongo?

Anyway - on my 1997 2.5TD it's actually 2700rpm at 70mph which equals just about 26mph per 1000 rpm.

Exactly the same as my previous 1997 "5 speed car" also a turbo diesel and also much smaller, lighter and more aerodynamic than the Bongo.

Simon Jones wrote:The gearing on the V6 seems to be slightly higher than the diesel: I seem to recall that 3000 RPM = 69 MPH,

That's 23mph per 1000 rpm - so lower gearing Simon.

It's all relative . It's different anyway.

Having done a GPS check of my speedo, 70mph is more like 65, so it does rev quite high for the speed.

Point taken about the size and weight, I just feel that the engine could easily pull a higher gear.

Nigel Hawes discusses in his factsheet on improving MPG, amongst other things, the effect of putting larger wheels on to increase the rolling circumference, thereby reducing the RPM for a given speed. He quotes a 10% improvement. Note that if you do this, you may have to adjust the speedo so that it's not under-reading (illegal).

membersonly/factsheets/mpg_improvement.pdf

That is a good idea..... so get hold of some 17 or 18" wheels.... I think the standards are 15" aren't they.

The Bongo under reads more than I expected, so bigger wheels might improve things. Not to mention the pimped up look !

Gripped wrote:That is a good idea..... so get hold of some 17 or 18" wheels.... I think the standards are 15" aren't they.

The Bongo under reads more than I expected, so bigger wheels might improve things. Not to mention the pimped up look !

There are discussions on here regarding larger wheels and the clearance they may or may not have under full lock or max suspension travel. I can't comment on those things, myself.

Edit: It should also lower the road speed at which lock-up occurs, which is another benefit.

Smaller tyres will make lock-up happen earlier.

Gearbox thinks ( speedo says ) you're doing 40, actually doing 36 ( for eg ), so lock-up is sooner.
Bigger wheels ( overall diameter, not just rim size ) means 40 ( speedo ) =44 actual ( eg depending on tyre sizes ) ,so won't lock until 44 in this eg.

Mine revs at about 2200 for 60mph, ( 225/70/15 tyres so slightly higher gearing than standard but 60 =60 )
When I had the standard 215/65/15 tyres 60 = 56, so revs @ ( actual ) 60 were higher ( less than 2500 tho' ).

Mine has pretty good kick under 40. At higher speeds it's less obvious but not surprising considering the work required to get a Bongo over 60.

I can't hear my turbo hissing so maybe you have some pipework that needs tightening. There is alot of "air" pipework.

skater wrote:Smaller tyres will make lock-up happen earlier.

My mistake.