Cab and Tin Top Petrol Tanks

Are the petrol tanks in the Cabs the same as the Tin Top?

I am putting a 16v in my Cab until i decide what to do with it and obviously i am going to have to fit an injection tank of which i have plenty from Mk1 GTI's but will it fit?

I can only presume it could be different due to the strengthening put into the shell by Karmann.

Euro Car parts list them as seperate items between the Cab and the Tin Top which got me thinking.

Secondly, what is the actual difference between the Injection tanks and the Carb tanks?

Cheers

Paul

Not sure on the Mk1 specifically but usually a tank from a fuel injecter car has a swirl pot and lift pump so that the inline fuel pump is always drawing fuel through and never takes in bubbles or a breath of air.  On carburettor cars the fuel pressure may be anywhere between about 4psi and 12psi - on an injection model it is between 60 and 90psi.  Indeed these new high pressure deisel cars (HDI stuff) run upto 1200psi which is enough - if you get a pin sized hole in the fuel line, to send a jet of fuel out that will cut straight through flesh and muscle.

One the carb models the petrol is drawn out via a pipe in the fuel gauge sender, the round thing under the back seat. On GTIs (and diesels I think) the fuel exits via an outlet at the bottom corner of the tank, next to the pump and accumulator. I don?t think any tintop MK1s had a lift pump in the tank but later Cabriolets may have had?

I remember reading the fuel filler pipes are different for Cabbys so perhaps the tank has a slightly different location of the inlet pipe?
 :dontknow:

PS I think that modern Diesels run at 1200+ BAR (thousands of PSI) 8O , thought that?ll only be at the engine end and not the lines from the tank.

I just know you have to be careful with them.  There are various HSE guidance documents kicking about the FIre and Rescue service giving warnings to make sure the fuel pump isn't running on these before doing anything else on one…

Ok, just as a follow up…….

Euro Car Parts have confirmed that all the Cab tanks are the same, but the Tin Tops have two which i/we already know.

So, does that mean the Cabs have a different type of fuel pump?

i.e an internal pump?

Any help would be much apreciated! Does anyone have a working copy of ETKA they could look at?

OK, checked EKTA and on an 82 Golf they list two numbers:
171 201 075P which is for the Carb models;
171 201 075Q which is for K-Jet and Diesal models;

For an 82 Cab, they list the same parts as the numbers above.

So I then checked a 90 Cab, and the same numbers get listed as above.

So, lokos like the cab tanks are the same as the tin tops according to EKTA but the carb runs a different tank to K-Jet.

I would say its becasu ethe K-Jet is preesurised system, where as the carb is not pressurised, so the K-Jet and diesal tanks are stronger due to the pressurised system they run.

Yeah, i just looked at that Russian site and it came up with the same results.

I'm stuck now, i guess i will just have to take the tank off my Cab and compare it to the Tin Top GTI tank.

I cant understand why Euro Car Parts say that all the Cabs use the same tank from '84 onwards regardless of it being Carb or Injection.

The only difference between the tanks is the outlet for the fuel pump by the looks of it.

The only pressure in the tank is vacuam pressure, not actual force fed pressure, when you release your petrol cap the noise you hear is air getting sucked in, not air coming out.

If you cut a coke bottle in half and submerge it in water then lift it up you will get a vacuam as the air is pulled into the bottle.

And the pressure mentioned above in Diesel engines is not from the tank to the pump, it is from the pump to the injectors.

One more question, has anyone used plastic fuel lines from a Mk2 on their Mk1 when putting a 16v in?

Websnowbo said

One more question, has anyone used plastic fuel lines from a Mk2 on their Mk1 when putting a 16v in?

I have a plastic return, though the tank to engine pipe is the usual Gti piece…

Cab tanks hold more of the 'go' stuff (12 gals - 60 ltrs) !!!
When I replaced the GTI cab tank I was told by my 'really excellent' VAG parts guy that it was specifically for the cab, its bigger, and has an internal lift pump.
The Clipper looks te same, apart from no internal lift pump !

Tank part number was - VA155201075B - price ?138.31 +VAT !!

So your GTI Cab has a lift pump?

Does it have an external pump too? Or just the internal one?

Getting somewhere now

I suppose later carburettor cabs may have standardised on the GTI setup, utilising the lower outlet.

Joining the suck or blow debate, ops:  I?m sure my GTI blows out when I remove the cap? I can?t imagine any GTI burning enough petrol to maintain a vacuum, esp on a warm day when the petrol is being sloshed around. The petrol will evaporate and create a positive pressure? If vented after about a day in mid August it would have all evaporated???  :dontknow:

I cant remember either! I could have sworn it sucked.

I dont know, but anyway, the tanks aint under any serious pressure, the diff between the tin top GTI and the tin top carb tanks is the petrol outlet positions.

But i'm still at a loss with regards to the Cab tanks  

Websnowbo said

So your GTI Cab has a lift pump?

Does it have an external pump too? Or just the internal one?

Both, when the internal one packed up it was a nightmare to drive - worse tan a kangaroo, and no guts at all, only going gently on the flat or downhill !!!
Main pump replaced 3 years ago, but it's always been noisy, had it replaced when an 'expert' garage said it was kernackerd, fitted a new one, - 'scrapped' the old one, charged me a packet, and it did not make any difference to my original fault.
Not been to them since……..

ETKA Doesnt show a lift pump in the Cabs, but it does in the 16v so i think i'm going to have aplay tonight and see if the 16v lift pump will fit in the Cab tank.  At least i will possibly be able to us the Plastic fuel lines then too.

Why not just leave a carb tank in and run the valver on twin carbs?!?

You know it makes sense!

Because the fuel pumps are ?100+ and then i still need a regulator and manifold.

I have the carbs but by the time i have bought the manifold, Pump and Regulator etc it will be expensive.

I'm only fitting the 16v because i'm going to VW Mania in Belgium in it and it is a bit sluggish on Motorways.

I'm going to G60 or 20VT it to make it more fun in the future.  I'm not really into modifying cars as such, but i just want it to be more economical and nicer to drive.

errr.... put a diesel in it then...... :roll:

Sorry, i didnt really mean more economical in that sense.

I meant economy in relation to performance