Are carb and injection fuel tanks different?

Post Sun Oct 11, 2009 1:15 am

Hi all,

As above, are the fuel tanks on injection and non-injection cars different?

Post Sun Oct 11, 2009 9:20 am

Post Sun Oct 11, 2009 11:08 am

Post Sun Oct 11, 2009 11:49 am

Well theres a difference of opinion for you!

I know that on cars ive had in the past they were different,but wasn't sure about e30's.
Is it just a different sender unit that slots in the hole?

Post Sun Oct 11, 2009 2:17 pm

Stifla wrote:Well theres a difference of opinion for you!

I know that on cars ive had in the past they were different,but wasn't sure about e30's.
Is it just a different sender unit that slots in the hole?

The tanks should be the same, as they're just a shaped metal container, but the injection car will have some form of swirl pot assembly fitted to the top. I'd be surprised if any manufacturer made different tanks for carb/injection cars as the cheapest way to do it would be to make all the tanks identical and have different components to send the fuel fitted into the same hole in the tank.

Post Sun Oct 11, 2009 2:57 pm

An in tank high pressure fuel pump, complete with fuel return pipe is a direct replacement for the carb. pick up pipe.

Post Sun Oct 11, 2009 5:55 pm

In tank pumps are no good for carb tanks as they dont have the bowl for the pump to sit in,

Inside carb tank -

Inside late inj tank -

If there is no bowl for the pump to sit in you will have serious fuel starvation on right hand bends

Post Sun Oct 11, 2009 11:01 pm

I know the bowl is missing, but the carb engine manages to pick up fuel without it!
Later 316 tanks seem to have the bowl fitted, anyway. (Based on a sample of one).

Post Mon Oct 12, 2009 12:23 am

Thanks for the info guys, i will pop my sender out and check for a bowl.

Post Mon Oct 12, 2009 12:34 am

Carbs have a nice float chamber for fuel storage and also the early level sender/fuel pick up will hold fuel when the rest moves to the other side of the tank.
Fit an in-tank pump to an early tank and your FPR wont be doing much work at all, even the slightest of right handers would cause fuel starvation, anything under half a tank and the car would be undrivable.

My car is a nightmare on hard right handers with half tank or less, ive been considering fitting a second in-tank pump to the passenger side of the tank.

Here is an E36 fuel bowl for comparison, no wonder the E36ists dont have this problem, its much deeper, holds more fuel and its harder for the fuel to escape

Post Mon Oct 12, 2009 6:59 pm

i still stand by my answer!! no they are not the same!! yes they may be interchangable

plus carb tanks are 55 litre and the majority of FI tanks are 60 litre.

Post Mon Oct 12, 2009 7:26 pm

mrLEE30 wrote:i still stand by my answer!! no they are not the same!! yes they may be interchangable

plus carb tanks are 55 litre and the majority of FI tanks are 60 litre.

If I'm reading the GSF parts list properly, it seems to suggest that the only difference is between pre and post facelift. Pre 9/87 cars get the 55 litre tank and the cars after that get the 63 litre version, regardless of them being carb or injection.

Post Mon Oct 12, 2009 7:33 pm

Most tanks are 55 litre in general, 63 litre tank only became an option with in-tank fuel pumps as the external pump will not fit next to one

Post Mon Oct 12, 2009 7:38 pm

If your E30 has a carb, a tank from an injection car will be useless

Post Mon Oct 12, 2009 7:45 pm

DanThe wrote:Most tanks are 55 litre in general, 63 litre tank only became an option with in-tank fuel pumps as the external pump will not fit next to one

Easy to retrofit?
My tank has a hole in it, and I'd like to go for the largest possible (assuming it doesn't alreayd have the 63 litre which I don't think it does).

Car is an '89 325 touring.

Post Mon Oct 12, 2009 7:49 pm

My very early 323 has a 58/60 litre tank depending on which parts list is consulted. That tank is NLA BTW.

Post Mon Oct 12, 2009 7:55 pm

If you can get your hand between the tank and the pass side sill its a 55 litre

55 litre

63 litre

Notice the extra hump on the 63 litre tank

Straight swap to upgrade to 63 litre

Post Mon Oct 12, 2009 7:56 pm

And, if I currently have the smaller tank, the sender unit from mine would still read true?

Post Mon Oct 12, 2009 7:59 pm

You would need to fit a second sender in the left side and fit a different fuel gauge to the clocks, just break into the wiring on the pass side of the rear seat, only one wire needs cutting

Post Tue Oct 13, 2009 10:02 am

yes! my point was no carbs would have come with the larger tank as no carb cars were offered as facelift

Post Tue Oct 13, 2009 10:14 am

mrLEE30 wrote:as no carb cars were offered as facelift

Eeerm! Sorry to be argumentative, but I have a facelift carb engined E30! The one that has a fuel tank identical to an injection car.

Any change from a small tank to a large one will also need the fuel return pipe re routed and the return pipe on the two pipe pump blanked off.

Post Wed Oct 14, 2009 10:54 pm

i thought only the M10 was offered as carb and this engine was discontinuied when the facelifted M40 engines came out???

what do you have brian??

Post Wed Oct 14, 2009 11:40 pm

Nope, loads of facelift M10's about

Post Wed Oct 14, 2009 11:51 pm

mrLEE30 wrote:i thought only the M10 was offered as carb and this engine was discontinuied when the facelifted M40 engines came out???

what do you have brian??

Facelift two door saloon on an 'E' plate, with a carbed M10 engine. I've also had a 2 door saloon, also on an 'E' plate, with a M40 injected engine, that had doors with the old type S shaped window winder mechanism, so, although the facelift bodywork for saloons was introduced at a specific date, it seems that for some time, some of the other bits could still be pre.