OK, barking maybe, but what about a manual petrol 80?

[Chris]

Let's try to be sensible here and keep within the bounds of the home mechanic - but how tricksy would it be to buy a lovely condition, low mileage petrol burner, whip out the autobox-a-tronic and whack in a manual box, with a clutch?

And - what would it turn out like? I would think acceleration would be epic. But would it mate up? Going manual box, with std auto diffs but 35" tyres would be right wouldn't it?

I'm serious. Having a very tidy manual box sitting outside and a yen for another cruiser, but a degree of economy being up there on the wish list. Hardware wise you'd need the clutch bits, some internal trim stuff.

What am I missing? Cross members perhaps? Anyone ever done this? Gary I know you had one in Saaarf Affrika.

Chris

 

[grantw]

What about the ECU ... is ripping out an auto box going to confuse that?

 

[Gary Stockton]

Yeah but it came from Mr T as a manual 4500efi

What about Mud?? Must be someone there who's done this? Sounds doable - new bell housing bits might be an interesting fit although I guess it'll be a plug and play - or hope it is. Trim on centre console will need work but that's just detail really.

 

[Chris]

I have the bell housing on the box Gary.

Hmm, ECU. Not sure. If I unplug all that off the box, all I need the engine to do is run. Throttle is manual as will be the gear changes. I'd need speedo drive which comes from the transfer box. But whether the ECU will be confused by not getting autobox inputs, I don't know. If the ECU on a manual / auto were plug and play them maybe I only need the ecu from a manual. Ahh, now that might be tricky. I don't want a Frankenstein's monster of a truck.

Chris

 

[OG.]

An autobox of that vintage has very few feeds back to the ecu. I can probably find exactly what they are (won't be much different to the A343F box in a Colorado which I have learnt loads about recently) if you really needed to know. Most of the electrical signals in the A343F boxes are the ECU telling the box to do something and assuming it gets done with no feedback loop to confirm it. If you can tell me exactly what box we need to know for I'll have a hunt round.

Basically they will likely comprise throttle position sensor, gear selection sensor, speed sensor, A/T temp sensor.
The A343F box can be driven with no electrics at all as a manual shift. I can't see the 80 series one being a lot different.

 

[Rob Voerman]

Hi Chris

I spent a lot of time in the dunes in SA and the 4500efi were tops, No stalling on long inclines, but JB the cruiser whisperer has the carb version with 33 and no problems, in fact they all ran 33's.

if I was to get an 80 I would not hesitate for the efi

I ran 35's on my 62 but the truck was geared for it

here are some videos. First one me, second a 4500efi with 35's but also geared
http://www.youtube.com/watch?v=difT3GmhyFU

http://www.youtube.com/watch?v=i8eJSSwNQM0


EDIT, Cant find the video of the standard 4.5 with 33's

will keep looking

 

[Chris]

All interesting stuff. Thanks guys.


I don't have any hesitations over the petrol engine. I never have. All except economy. I know we don't buy these things to get 50 mpg out of them, but as I have said many many times, the difference between 30 mpg and 11 mpg is not a trifling matter at today's pump robbery. Offsetting some of that overall cost by buying the petrol version of the 80 is apparent. Nicer cars, cheaper. More expensive to run - but that's not the only element in the cost equation.

The purpose of this project is to investigate whether I can get a tasty 80, cheap and then increase the economy by dropping a spare manual box into it for nothing. A petrol 80 that would do let's say 20 mpg on 35" ATs on a long run would be a doozie. Point is, I don't know what a manual petrol would be like.

If we don't dream it's not worth taking part, eh?

Chris

 

[stumog]

i have just driven a 4.5 80 manual in SA its really really bad on fuel. i think we were getting about 700km to about 130-140 l. which at £1.40 l thats alot of cash.
Did go like a rocket when you wanted it

 

[Gary Stockton]

Tell me again why I sold this????

Grrr...

 

[Rob]

You will need manual props as the TC will be further forward, and you will need to re-weld the gearbox crossmember bracket to the chassis or make a new one.

I have serously looked into doing a manual swap on my Volvo and as my engine was not available in manual configuration I need custom ECU software to make it work as the engine ECU talks to the gearbox ECU and they decide how much throttle you are aloud to have. Also messes with the air con, cruise control and reversing lights as they all rely on a signal from the gearbox ecu to function correctly. Also the map on my Volvo is tailored to work with an auto box with a torque converter, so it has not been mapped to provide max torque available at 1000 rpm continuously as you would expect the gearbox to shift down or the engine rpm to increase due to the torque converter characteristics. As a result if you use the wrong ECU it may run rich at low rpm WOT situations and cause excessive smoking (this is what happened to someone who just got my Volvo ECU to work with auto box but did not adjust the map). As it's EFI the maps will most certainly be different between the manual and auto versions.

You need to find out if there is a manual version of the exact engine and car you are looking to buy, if so it may just be easier to unplug the gearbox ECU and replace the engine ECU with a manual one, bypass the park sensor dependant start circuit and sort the mechanicals out.

Other than that, all I can say is a manual 80 is great fun to drive.

 

[Rob]

Tell me again why I sold this????

Grrr...

Because you dinged the side step

 

[Chris]

Because, Gary, you is a mental. innit.

Sound words there Rob. All a lot of work. OK on an off roader which can have quirky bits but maybe not for a pristine road goer. Incidentally the figure quoted above give between 14 and 15 mpg which when plugged into the £/mile calculator gives around 40 pence. So not good enough. Not if that was cruising. If that was driven hard point to point then it would be pretty good.

Chris

 

[Graham]

Go Chris,

If any one can make it fit, I have all the confidence in you.
If the electrics are bothersome, then you and OG, get together, maybe, after all the mechanical s are done.

Simples,

I am sure you of all people can fit all the mechanical s together.

Gra.

 

[stumog]

those figures where driving nice and steady not like a nutter.
its a nice thing to drive if you can afford the petrol. i couldnt even think about running that over in the uk.
they do recon when off road the petrol and the diesel arnt that far apart in the amount of fuel they use so if its a play toy
good luck and you will have a massive smile on your face. i like to call it the 4.5 smile.

 

[Andrew Prince]

Chris, what makes you think a manual is going to give you (measurably) different fuel consumption versus an auto in a petrol 80? In the diesels, the autos arguably give better consumptions than the manuals, certainly the autos are on a par at worst.
Gearing will play a very big role in the consumption, particularly with a petrol 80 where a 10% difference in economy can be the difference between needing to hijack an oil tanker or not. If most miles will be done on a motorway at constant spend, I doubt the gearbox will make much difference, especially if the engine speed is the same for a given cruising speed (i.e. gearing is the same).

Even if a manual box will give you some fuel saving, running 35s will more than eat that up I reckon. You clearly have an itch to do the conversion, so I say go for it. Maybe get counselling for the fuel economy worries - best/only solution IMO

 

[Rob]

In the diesels, the autos arguably give better consumptions than the manuals, certainly the autos are on a par at worst.

You sure its not the manual diesels that use less fuel?

 

[Gary820]

Is it bad I don't think the mpg is that bad from the 4.5?!
If you do the conversion it'd be interesting to see how much difference it makes.

 

[Chris]

Andrew! Hi there, how's things in the third World. Missing our varied and unseasonal weather yet, ridiculous laws and rip off economy?

Look, I am not stating anything here, I am asking. Just shooting the breeze as it were. Why MIGHT a stick be more economical than an auto? Because you can change gear when you like. Being stuck in a convoy down the A75 at 53 mpg in an auto means that you are 1 mph away from top gear. In a manual, well, you control your destiny a little more. You can short shift, yes?

On the subject of 35's my point is that if I bought a 24v diesel manual, I could drop the diffs and put in my spare 4.3's. My understanding was that the output of the manual gearbox needed the lower 3.7s or whatever they are to give the same gearing as the auto on its standard rubber. So, if I took an auto and stuck a manual box in, I'd be replicating all of that diff swapping stuff ending up with a petrol, manual on 4.3 - right for 35's. Or have I missed completely? The only way to re gear a petrol auto would be to A build new custom diffs in say 4.56 OR drop in a manual box and keep the 4.3's.

Look highly unlikely that I am going to do this, but it was a thought. You just cannot argue with the fact that there are bucket fulls of spanking low mileage petrols out there for stupid money. But one limiting factor is that I REALLY want to stick the 35's on. But a petrol with STD diffs would be enough to drain my bank account if I stuck the big boots on it. So this isn't about simply having a manual petrol, it's a manual petrol on bigger wheels. Maka-de-sense?

First person to say LPG gets a bullet by the way.

Chris

 

[uHu]

Petrol 80's drive wonderfully. Used to drive a couple of them, mainly highway/town, pulls well and wonderful sound. Compared to all the 1HZ versions we had, it was a rocket. Never tried an auto version tho'. Afaik, the auto boxes are stronger - tuned engines combined with manual give problems.

 

[Ben]

I almost mentioned the L word earlier Chris in your insurance thread.

Glad I didnt now.

What have you got against L**?

Not read of you not liking it before.