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Top speed

Posted: 30 Sep 2019, 09:58
by Novastrike
Hi folks,

I was chatting to some beetle owning friends regarding my 1.9 watercooled t25. They seemed very surprised at my comment that it was maxing out around 60-65 mph. This seemed reasonable to me.

Can I ask if this sounds about right for a untuned, standard 1.9 lump with a High top?

Many thanks!

Re: Top speed

Posted: 30 Sep 2019, 10:23
by Fugeh
Thats about the same as mine :ok

Re: Top speed

Posted: 30 Sep 2019, 11:59
by phinw
Not far off I would guess. It all depends how much stuff you have in it! My stock 1.9 DG with a hightop and a reasonable amount of camping interior, assorted guff + wife + child + dog will manage 70mph+ with some encouragement and good run up (but no one can hear themselves think let alone speak!). However it will cruise quite happily at 60mph on the motorway. So perhaps yours may be a little down on power?

Re: Top speed

Posted: 30 Sep 2019, 12:02
by Aidan
should be able to do more than 70, don't forget you can rev to 5000rpm
it's possible you have the wrong gearbox, check the code; or you don't rev much over 3k :D

Re: Top speed

Posted: 30 Sep 2019, 13:49
by 937carrera
Key determinants of top speed are engine power, aero drag (van, pop top / high top) and possibly gearing if the gearbox is wrong.

I have a calculator that simulates top speeds for any vehicle, fot the T25 with a DG engine you should be looking at a top speed of a little under 80 mph https://forum.club8090.co.uk/viewtopic. ... 7&t=164160

If the engine simply will not pull any more, as opposed to running out of revs, I can tell you how much power your engine is actually developing later on today

Re: Top speed

Posted: 30 Sep 2019, 15:03
by 300CE
Since the engine/carb rebuild and new exhaust, my bus is certainly a lot more sprightly, but i always drive to a maximum of 60 mph which it reaches with ease (certainly if it is passenger-less). I have my rev counter limit set to 4300rpm and take it gently through the gears - I reckon that she'll hit 75 without a problem though.

Re: Top speed

Posted: 30 Sep 2019, 16:41
by Cobra88
most I have seen on my Auto DG is 77 mph on my GPS
Slightly downhill on M20

Handbook says mine has a top speed of 77 mph to so happy.

sits all day on motorway at 60-65 comfortably.

Re: Top speed

Posted: 30 Sep 2019, 16:43
by Jim San
Novastrike wrote:Hi folks,

I was chatting to some beetle owning friends regarding my 1.9 watercooled t25. They seemed very surprised at my comment that it was maxing out around 60-65 mph. This seemed reasonable to me.

Can I ask if this sounds about right for a untuned, standard 1.9 lump with a High top?


Top speed is not a subject of interest for T3 ownership really :rofl


Conversation should go something more like "does it always get you there on time?", "yes"
If not, set of a few mins earlier next time :run

Re: Top speed

Posted: 30 Sep 2019, 18:03
by shepster
Or, does it get you there at all!

I swapped for a 2.1 but don't really go any faster than the 1.9, hills are just a little easier.

I guess your beetle mate hasn't taken in account almost 2 ton of bus with only 70 odd 'osses pushing it along.

Re: Top speed

Posted: 30 Sep 2019, 18:55
by Mocki
I can bearLy get into 5th at 60, it’ll do 75 in 4th on the flat , but I have oversize wheels and tyres (16x225 c) and a tall gearbox . It struggles on hills if I don’t or can’t keep the momentum , but eats motorway miles , 70( gps speed ) is 65 on the speedo and 2800 rpm

I would say you should have a top speed of more than 70 , maybe you need to push it a bit harder , it’s not at peak power till 3400 rpm you know

Re: Top speed

Posted: 30 Sep 2019, 21:07
by 937carrera
Mocki wrote:it’s not at peak power till 3400 rpm you know

Peak power for a DG is at 4600rpm - the torque and power graphs are in the thread I linked to earlier.

If the top speed really is an actual 65 mph, then I would estimate that the engine is only producing 48 bhp. Of course, if the speedo is under reading then engine power is better, have you tried a GPS speed?

Re: Top speed

Posted: 01 Oct 2019, 08:08
by Novastrike
Thanks Mocki,

I only have a 4 speed box, don’t know if that’s impacting it. I will try a GPS speed measurement

Re: Top speed

Posted: 01 Oct 2019, 08:14
by ash1293
I've said it before on other threads but..... check for slack in the throttle cable.

When I bought our leisuredrive hightop it seemed to top out around 60mph, much more and it was a reall struggle. Simply adjusting the throttle cable brought it back to life and could then easily acheive 65-70mph. When stripped out for rebuild it would nudge 75-80.

Since rejetting the webber 34dat its much better again, quite nippy for a brick and easily get up to 65 for cruising and will push on when required, obviously the economy starts to suffer.

So start by checking the basics before assuming its a tired old engine.
- if its not been serviced in a while check air filter, plugs, leads, fuel filter etc
- borrow a strobe and check timing
- check throttle cable, adjusted by removing drivers front indicator. Check you are getting full throttle when pedal depressed.
- check for split vacuum hoses

If all is good then you could always see if anyone has a compression tester you could borrow to see if still within specification.

Re: Top speed

Posted: 01 Oct 2019, 09:02
by 937carrera
ash1293 wrote:Check you are getting full throttle when pedal depressed.

That's a very good idea, and often missed :ok

4spd/5spd doesn't make much difference, the top gear is usually about the same, it's the first gear and spacing that changes

Re: Top speed

Posted: 01 Oct 2019, 09:39
by bigherb
It might have a DF engine which was for the delivery van market, good for urban acceleration and fuel consumption but runs out of puff at higher speeds.