How to make my fleetline go faster

[smokinbus]

Hi all

I am driving my second fleetline now and I'm having a problem getting it to comfortably go faster than 85 km/h. I completely overhauled the engine - took it to a very reputable engineer in Pta (Basil engineering works), imported brand new cylinder heads (hard to found decent old ones these days). It's a stock twin port 1600 engine that fleetlines came with.

I currently have 175 tyres on front and back.

My first fleetline had 185's on at the back and I remember quite easily cruising at about 95 km/h on the straights and maintaining 90 km/h up gradual hills. I could get to 100 km/h and higher but the engine wasn't happy at those speeds. Maybe it was all an illusion because it had 175's at the front and 185's at the back - speedo attaches to front left hub - so this would be turning slighty faster than back wheels)

I'm going to do a long 2 week trip around the cape in December with wife and 2 kids .. packing the car with windsurfers, bikes, tent ... (Augrabies, Paternoster, Bredarsdrop, J-Bay ...) and I would like a bit more speed especially when overtaking trucks - I can live with the beamers flashing their lights at me to move over - my reaction is just to slow down even more

Any ideas on getting more speed would be great:

Larger tyres?
Change reduction box?
Change gearbox?
Porshe engine with new gearbox ... naah I'm a purest

What kind of speeds do you get with your busses?

smokin
http://picasaweb.google.com/david.lloyd ... 1471268162

[Merlin]

You're pushing your fuel consumtion WAY up over 85, and I personally won't take mine over 95...the engine will start overrevving with little more than that.

I cruise eveywhere, long distance too, at 85, quite happily.

I can notice a substantial difference in my consumption at 90.

I run 185s front and back, with a stock gearbox and reduction 'boxes, and my healthy OG engine.

...don't think about removing the reduction boxes...they were put there for many reasons!

You're asking for major engineering Sh*t, height issues, ratio problems, etc.

It's a good idea to recon the reduction 'boxes and gearbox - they're nearly 40 years old!

PM me for a gearbox place recommendation.

Have your engine opened up and checked by a reputable person...most pull VW 'knowledge' out of their ar5es.

...and slow down.

Too many people want a splittie that drives and handles like a modern car...then get a modern car.

N.

[fig]

Factory redline was at 105km/h; I never drive my Fleetlines over 100. I find 90-95 a comfortable cruising speed, but, as Merlin notes, below 85 is best for fuel economy.

Do you perhaps have a Beetle box in your bus? Buses had a taller 4th (.89 vs .82), and many Beetle boxes also have lower final drive ratios.

[smokinbus]

Thanks tips merlin and fig

I can feel something's not right with this new bus on the gear ratio side, when you've driven another bus for many years - you just have an instinct. Good call on the gearbox - I guess I could check if its an original fleetline gearbox by looking at the part number on my gearbox - any clues where to look for the part number - please don't tell me it's on top of the gearbox where I can't see it

What size tyres do you use fig, how much of a speed difference do you think tyres make?

I guess a complete overhall on the reductions boxes and gearbox is not a bad call either - my left reduction box wastes all its oil out in about a month - although my gearbox shifts as smooth as silk and hasn't jumped out of gear once on me - it's just darn slow ... at 90km/h it sounds like the engine going to fall out it's revving so high and I just have to drop back to 80

[smokinbus]

ok got that gearbox code - stamped on a rib between the final drive and the shift mechanism on the right-hand side.

BA 26 09 4

A bit of internet searching showed that the BA means it is a 4.375 ring and pinion ratio and the 26 09 4 just means it was manufactured on 26 of September 1974

Shedding any light?

[fig]

I don't know about transmission codes, but that R&P sounds like 1300 Beetle. I may be wrong, but that would explain your gearing issues.

[smokinbus]

Figured out all the maths behind my problem! and it shows a 15% difference in speed

Here goes:

A normal fleetline gearbox (65-67 transmission) should have the following specs:

1st: 3.8
2nd: 2.06
3rd: 1.21
4th: 0.82
Final drive (R&P): 4.125
Reduction box: 1.26

What I have (checked on internet for BA code - fig is right) is a 1300 beetle gearbox with the following specs:

1st: 3.8
2nd: 2.06
3rd: 1.26
4th: 0.89
Final drive (R&P): 4.375
Reduction box (stays the same): 1.26

If you want to work out the final ratio of 4th gear - you multiply Gear ratio X Final drive X Reduction box

What I should be getting if my gearbox is right is:
0.82x4.125x1.26 = 4.26195

What I'm getting with the wrong 1300 gearbox is:
0.89x4.375x1.26 = 4.90612

So if my top speed is currently 85, what I could be getting with the right gearbox is

new speed = 80 x (4.90612/4.26195)
new speed = 80 x (1.151144)
new speed = 97.85 km/h

Change from 175 to 185 tyres and I'm sure this creeps to 100 km/h

I had no idea when I bought the thing that the gearbox was wrong - it had no engine and it was a year before I got it on the road.

So now what to do - these gearboxes are as scarse as hens teeth. I might approach the guy I sold my old fleetline to, which had a gearbox that was right but spurting oil and needing a recon and ask him if he doesn't want to swop a gearbox thats working like a charm but slower, then I'll recon that my old gearbox.

Or ...

Is it possible to just swop out the R&P and 4th gear in the 1300 beetle gearbox and keep the rest intact?

[smokinbus]

Typo in my formula

new speed = 85 x (4.90612/4.26195)
new speed = 85 x (1.151144)
new speed = 97.85 km/h

[fig]

AFAIK you can swap out the 4th gear and R&P.

[brianj]

Just while we are on the subject... I have a box which is SF AC 4576153.... does that sound right for a 67 d/cab.
I think not, but will be happy as long as its a fleetline 'spec' box....

[smokinbus]

The key part of the code is the AC part - that's a 4.125 final drive which is cool - maybe a few other people can check their gearbox codes and confirm what the standard code is for a fleetline and for various models of german busses.

gearbox codes see here:
http://www.partsemporium.co.uk/Gearbox%20codes.htm

List of Gear Ratios see here:
http://sandlizrd.baja.com/gears.htm

[brianj]

Thanks, I am also hoping to have the .82 4th gear.. it makes 10km/h difference at the top end... The beetle one is .89, but it looks like the codes are the same...