Fuel system Q's

[benny c]

Hey guys, my soarer re-build has gone a tad more track-spec since the boss gave me a car to drive around in. I'm now in need of some advice on the fuel system, as I think I can hazzard a guess and say that the stock one won't be up to the job.

At the moment, I am aiming for 300rwkw as a minimum. I only have the stock fuel system at present. I know I will need a surge tank as the car will see some track days and targa useage. So basically if I use the stock in-tank pump to fill a surge tank, then a bosch 044 (or similar) to feed the engine, this sounding about right?

The other option is to make a custom fuel tank from scratch. The lads at the workshop are just itching to fire up the tig and make something up, but unless I can use the stock fuel level sender (JZZ30) this won't be happeneing as I will still be running the standard instrument cluster.


Cheers

[Draven]

lift pump (stock pump will be fine for this) -> surge tank -> 044.

This is what I'm doing for my supra at the moment... should be good to push close to 400rwkw, which is really more than you'll ever need

[benny c]

Cheers mate, much appreciated

[TheDarkRaver]

Yeah I am just in the proccess of installing the same setup in the Cressida

Std intank pump --> Surge thank --> 044

I am aimming for the 350kw mark and should be able to support that no worries..

[benny c]

Are you guys keeping the stock hard line running from the back to the front of the car, or replacing it with hose? The flare nut on the front side of my hard line got damaged taking the engine out of the car (think it was cross threaded on previous installation) so I was thinking of re-doing it with hose, possibly in a larger diameter?

[Yojimbo]

there is no need these days for such primitive solutions as big bosch pumps ans surge tanks. Most modern tanks have a natural bowl that gathers fuel near the pump inlet and a pair of walbros will take care of the pumping. A single -6 line forward will have plenty of capacity. Use your old forward line as the return if you are on a budget. I used black pushlok for all of this. I'm told the pushlok will smell of fuel but I am yet to notice any smell. Teflon braided line will not smell but will also rub through and destroy every thing it touches.

[Yojimbo]

Oh and before the doubters kick in... Twin walbro no surge tank setups regularly support 600 rwkw both here and in the us.

[Norbie]

The swirl pot in the tank is nowhere near as effective as an external surge tank. It's fine for street use but since this car is being used for "some track days and targa usage" a proper surge tank is a very good idea.

[Draven]

with norbie. JZA80 swirl tank is great for the street but they're notorious, with the grip JZA80s can generate, for surging (especially on slicks). Can only imagine a JZZ30 is similar

[The Real Roadrunner]

Oh and before the doubters kick in... Twin walbro no surge tank setups regularly support 600 rwkw both here and in the us.

But its a great way of destroying an engine when 1 pump dies in the arse (could be many resaons).
Also im yet to see a std fueltank in any production car be able to cope with excessive track abuse at low fuel levels, even on street tyres.

Do it properly with 1 main pump and if your don't take it to the track then just fit the pump intank, the KISS method makes life easy.

Cheers
Linden

[TheDarkRaver]

I would have to agree on the intank punp thing aswell.. I have had a look in quiet a few different modern efi cars fuel tanks and the bowl that usually surounds the intank pump is nothing special.. Like the others have said around a tight long corner running less than say 1/2 a tank, it wouldnt take long for all the fuel in the bowl to spill over and leave the pump running dry..

If you are planning on the occasional track day etc I would deffinetly stick to the surge tank idea with the single bosch.. (especially when you way up the cost of a blown motor vs a surge tank)

As for fuel feed line I will be running 1/2" (12mm) flexi metal pipe half the way then fuel resistant rubber hose the rest of the way.. Then using my std feed as my return.. Oh and 1/2" is -8, I cant see -6 being much bigger than a std fuel feed line anyway? Seems too small to me..

[Yojimbo]

Also im yet to see a std fueltank in any production car be able to cope with excessive track abuse at low fuel levels, even on street tyres.

there is a easy solution to the low fuel level problem, and if you have enough HP to needa big pump then 15 kg of extra fuel wont slow you down. I dont ever intend tracking my car without 1/2 a tank fo fuel.

let it be known Im not arguing here, everyone has raised (quite) valid points, i guess Im just raising an alternative view, Im over compromising nice cars with crude and noisey support systems, for the half dozen events a year the car may do, when a few simple precautions will do.

I guess you have to decide how "track spec" you want to make it.

[Draven]

there is a easy solution to the low fuel level problem, and if you have enough HP to needa big pump then 15 kg of extra fuel wont slow you down. I dont ever intend tracking my car without 1/2 a tank fo fuel.

which is great for the first half or 3/4 of the track day, until you drop below half a tank

That's what I have to do at the moment (run above half a tank), but it means less time on the track (even with a jerrycan to top it up)

[Yojimbo]

yeah like I said, it is a compromise.

I prefer my car not to have noisey external pumps for the other 15000ks a year it does on the road in traffic. I recently had this setup, and couldnt live with it. Sold it all off.

[-GT-]

Also im yet to see a std fueltank in any production car be able to cope with excessive track abuse at low fuel levels, even on street tyres

Mine. Every track day i run right down and do at least one session entirely on the light, sometimes two - never had a single surge or miss in years. Sure, i don't have the fuel demands of some of the other people in this thread, but it's an entirely factory setup - from 1989... still the original pump too!