v6 fuel tank into 4cyl?

[BradGTV]

im currently converting my 79 gtv to EFI,
i have been looking into the fuel system, im just wondering if a fuel tank from a gtv6, 90, or 75 will fit into the gtv?
iam assuming the v6 tanks have a baffle in them?
cheers, brad

[MD]

Hi Brad,

I take it that this is for a track car?
For my previous race car which was an Alfetta sedan, I installed a VL Commodore lift pump and the obligatory return to tank fitting in the original tank. No problems. With a surge tank, baffles in the main tank don't seem to be an issue.

In my opinion leaving the original tank where it is provides a lower centre of gravity and it is a retrogade step to place it in the boot. The second advantage is better segregation of the fuel from the passenger compartment should the tank be ruptured.

A fuel tank in the boot for a GTV should only be fitted there for rally cars for obvious protection of the tank. Track cars no. Apology for rabbiting on if this is a road car..er road car, you lose a lot of boot space.

[BradGTV]

hi md,
thanks for the info.
i didnt realise that the v6 tanks were in the boot.
i think i will just have a drop tank welded onto my tank.
yep this is for my supercharged track car

[MD]

i will just have a drop tank welded onto my tank.

Brad,

(If I understand you correctly)

That seems a little overkill. Welding tanks that have had fuel in them before is a dangerous job and requires special handling techniques to do it and this will cost you serious bucks.

The simpler solution is to install and off the shelf surge tank which is fed from the primary low pressure pump or lift pump. The cost of this will be chicken feed in comparison.

[BradGTV]

hi MD
i thought having the tank welded on would be the cheaper of the 2 options. i think i will make up a surge tank out of a piece of 75mm ID aluminium tube i have, what would be a good capacity? im thinking 1.5 liters?
because it is a tack car. the rules wouldnt permit a fuel system inside the car would they? does the surge tank, lift pump and efi pump have to be in a seperate sealed box in the boot?
cheers, brad

[MD]

Brad

1.5 litres will do it but 2 is better if you can fitted in. The 75 id tube will be too small and will result in the the tank being too long for where I suggest you place it to keep the scruteneers happy.

I suggest to loose some weight and cut out the wheel well. Install a flat aluminium sheet in its place. Give it some stiffening ribs. Now you have a platform to SUSPEND your fuels system from and away from the exhaust (if you run it to the rear). (Another reason to run it out the side and lose some weight in the process).

The boot floor makes for an effective fuel to compartment separation and will comply with CAMS specs.

If you put it IN the boot, you must ensure a complete sealing off from the passenger compartment. More stuff, more weight and no gain.

[Darryl]

Excuse the sorta hijack, but as the subject seem to be options for fuel systems in 116 cars + what CAMS and others will think of it:

Question for MD (or any lurking scrutineers?)

If for one reason or another one didn't want to take your (good by the way - I'm thinking about it) suggestion re the spare wheel well... How "sealed" is sealed? Obviously more sealed than my Turbodelta GTV was (fuel pump under back seat - gave me a fright when I found it there!)...

Specifically - If I stick a sheet of aly on the panel behind the seat + the parcel shelf is it "sealed" from the boot? Oh - I'm talking about the Alfetta sedan btw - Jim thinks better safe than sorry re avoiding any risk of fuel starvation leading to being able to blow fuel back out of the float chambers under boost so I have a fairly overkill approach in mind (decent lift pump into surge tank in boot + a grossly overrated re. flow @ pressure main pump).

I assume I need to get this engineered if I want it on the road - anyone know what the rules are there? I can't see that whatever I do can possibly make things worse than the less than fail-safe existing/standard fuel system - but I suspect that argument won't wash....

tx
Darryl.

[Sheldon McIntosh]

So where's the tank in the GTV? (Sorry for my ignorance)

MD, are you saying that the pump and surge tank are suspended underneath the car with this mod?

Darryl, our scrutineers pass alloy sheet screwed to seat panel and parcel shelf.  It needs to be sealed well though, with silicon or rubber. 

I have a 1 litre surge tank, I think the guys I bought it from (EFI Hardware in Melbourne) said I'd be needing about 400bhp before I'd need much bigger than that.

[MD]

Sheldon,

Yes

Darryl,

I am not a scruteneer but I have been scruteneered.

What is acceptable under ADR's and CAMS are not the same. What is OK on the road is not always OK on the track and vice versa.

How sealed should it be?

If you answer this question yourself in relation to your own car, you will know. The question is this: If your car rolled over and your fuel system in the boot was fractured, penetrated or distorted so that it leaked fuel, where would the fule leak into the cabin from?.. Once you have found all the openings, you need to plate and seal them all off.

To give you some idea. For the race car that has a fuel tank and system under the boot floor, I had to completely encapsulate the filler from the cap end to the tank end in metal sheeting and seal it.

[Darryl]

What is acceptable under ADR's and CAMS are not the same. What is OK on the road is not always OK on the track and vice versa.

To give you some idea. For the race car that has a fuel tank and system under the boot floor, I had to completely encapsulate the filler from the cap end to the tank end in metal sheeting and seal it.

Thanks MD. I realize that the ADR vs CAMS rules are different.... but for older cars at least the ADRs are mostly not too onerous. Hence my concern is far more about what happens if I turn up at the track...

Between your input and Sheldon's, I think I'll just seal off the whole boot - If I try to seal off just the filler and vent + anything else that ends up in there its going to get complicated pretty fast....

[Sheldon McIntosh]

Sorry, I forgot to say, when I talked about "our scrutineers" I was just referring to our club sprint days, don't know if that is relevant to what you do Darryl.

[MD]

Sheldon,

Apology. I overlooked answering your second question.

Tank locations :-

GTV 2.0 > LHS under boot floor
GTV 2.5 > Centrally between shock towers in the boot
Alfetta Sedan > RHS under boot floor

Even though they are all transaxles,note the potential difference in the handling balance of these cars based on the weight distribution due to varying tank locations.

Darryl,

If you keep everything under the floor, you should not need to go to too much trouble with the boot. The reason I had to seal off the filler area is because I had no boot (so to speak). If you leave the boot original, I think you will not be asked to do anything. However, it alway pays to get some advice ahead of time from actual scruteneers.

[Darryl]

MD,
As you know there is SFA space to the right of the exhaust. and/or in front of the tank. If I get rid of the spare wheel well I could run /move the exhaust to the left of its std location, and have some space adjacent to the tank for surge tank, pumps etc. Personally, never mind what CAMS and/or ADRs say, I'd be feeling safer with it inside the boot and well forward.... Regardless I would still have filler via boot into top of std tank that, if being pedantic might need secondary containment/separation from passenger space, so I'm not sure that I don't need to better seal (block of the big cut-outs at least) in the panel behind the back seat and the parcel shelf regardless of where I put the tank + pumps...