fuel pump/surge tank questions/idea's

[JZA70 R]

i'm designing a simple fuel system for my car (jza70) to support ~400rwkw and im planning on doing the following, but have a few question along the way...

stock tank with stock pump inside acting as a pickup to a ~1L surge tank. surge tank delivers to a single externally mounted bosch 044. 044 feeds to factory fuel filter and from there its all oem lines to the oem reg and rail. rail has 800cc injectors. fuel is returned to the surge tank via oem return modified to mate with the surge tank. when the surge tank fills up, a custom made line will return fuel to the fuel tank.

in theory im hoping this design will put zero load on the 20 year old oem pump prolonging its lifespan. im also hoping the oem pump will flow significantly more with no load hence keeping the surge tank 100% full until which time the 044 is delivering more fuel to the injectors than the oem pump can provide to the surge tank, even then you still have fuel returning to the surge tank from the rail so I cant see how this surge tank can be emptied with a ~400rwkw engine combination utilizing 800cc injectors...?

my questions are as follows...

do i mount the surge tank and or fuel pump inside the hatch area of the supra (thinking wheel well) or do I mount either or under the car?
my major concerns here are 1. noise 2. legality 3. complexity (wiring and plumbing) and 4. safety... in that exact order.

my next questions are regarding power to the pumps...
my auto electrician wants to run both the oem pump and the 044 without a hi/low trigger (ie always 12/14v) but if i choose to mount the 044 inside the cabin I will be concerned with its constant noise @ ~14v and also the possibility of it heating the fuel up...
do you recommend running either of the pumps off high/low triggers or constantly at full power?
obviously it would be nice to get rid of the oem resistor in the engine bay and its associated wiring.

some points of interest that have been brought to my attention lately, but may not neccessarily be accurate or correct are...
will fuel still be heated in a pump running 14v if there is no load on the pump (ie oem pump)
will a fuel pump burn out faster operating at 14v with no load compared to a pump running at 14v with 40psi load?

thanks

Todd

[darby]

if it was me i would run twin 044's down twin stock size fuel lines and filters and convert your fuel rail into twin entry type. only cos 044's are good for a proven 350rwkw each approx and your better to have too much fuel rather than not enough. 1l surge should be fine but i wouldn't be to confident with a 20yr old lift pump. consider maybe a holley or facet low pressure lift pump (not expensive). external mount surge and 044's would be best for noise, legality (if engineered), safety and will stop the horrid smell of feul in the cabin. wiring and plumbing not hard. as for the 14v, the 044's will run quite happily like this and wont heat fuel noticeably. not sure about the stock pump

[2jzhilux]

A carter black or facet pump is only about 120 dollars, i wouldnt risk using an old stock pump.
What turbo are you planning on using for 400rwkw

Im running a carter black lift pump into 2 044s into a 2.5 litre surge tank but i havent had to use it.
Listen to 1 044 and you will mount it outside for sure, i also dont like the idea of having fuel in the passenger area.

[88cameron88]

a 044 is a 700 pump
the set up you have in mind should be fine i think, i run the same set up an i dont run out of fuel but im not making that power though. I run both of my pumps full time from the moment i turn the key to when i shut it off. I wouldnt be too worried about the pump heating your fuel up, its not going to be that bad, and i dont think you will notice a difference in power anyway, and it if it does worry you that much then think twice about having your return line go back to your surge tank because you will definately have hot fuel running straight back through your system then!!

[Draven]

mount the pump outside the car with rubber dampers on it, or you will go insane within a few days.

if I had my time again I'd go a high volume low pressure lifter into the surge tank, into the 044. unless you have exactly 400rwkw as your goal, I'd be happy with one 044 pump - it'll get you pretty damn close to that figure

[JZA70 R]

hoping a GT40R or maybe even a 37R will get me there. waiting to see what these new garrett GTX-R turbo's are capable of too.

as for 044's... a good mate was making over 630rwhp on a single external bosch 044 although he admits it was close to its end and it was at a slightly higher 45psi base pressure.

RSOL over east is making 616rwhp on a single IN TANK bosch 023 which is a similar size iirc. These guys are the reason I want to try just one.

Someone did the math on here not long ago and it was said that even if you starved your lift pump for like like 20 seconds while WOT, you still wouldnt drain a single 1L surge tank. hence anything bigger being a waste of space... food for thought i guess.

[darby]

i wouldn't risk thoes figures on only one 044 pump. not enough fuel at full noise= lean burn missfire= bye bye engine. a few hundred on an extra pump alot cheaper than a new donk

[JZA70 R]

thats what AFR and FP sensors are for. monitoring fuel burn and fuel supply so you pickup on these things before they happen.

if the pump was being maxed out then no matter how much extra fuel you put in the injectors(via the ecu), your AFR's wouldn't change. Im assuming fuel pressure would drop at peak boost/torque also if the pump was running out of steam.

[mr1jz]

If you are aiming for 400rwkw reliably, then run two 044's. One 044 is on the limit or already past it. Pressure won't be the issue but flow will be. Why would you spend all that time and money engineering a fuel sytsem that will be on the limit when you can do it right the first time. I would also be looking at changing the OEM intank pump aswell to a Walbro or something of the like because at least then you know it is all new.

[JZA70 R]

would of thought the oem fuel lines running under the car would become a flow restriction before a 044 would be...

[senn]

I'm wondering the same thing about the standard fuel lines, as i'm about to upgrade my standard intank pump, altho mine is a way smaller engine + power goal. I was thinking of going to full braided lines, bit i would assume that would mean modifying the tank outlets?

Also on your car JZA, wouldn't a stock pump, feeding a bigger pump eventually run dry, with continued hard driving? eg 80l/hr pump main feeding 300l/hr pump in surge if you were pushing hard i'd imagine that eventually the surge tank would be dry...but i've not had much to do with fuel systems, so this is just a guess

[Draven]

I
Also on your car JZA, wouldn't a stock pump, feeding a bigger pump eventually run dry, with continued hard driving? eg 80l/hr pump main feeding 300l/hr pump in surge if you were pushing hard i'd imagine that eventually the surge tank would be dry.

In theory yes, but how long are you ever at WOT for?

rarely, if ever, more than 30 secs one would think, so as long as your surge tank can supply your engine for 30 secs at WOT, it doesn't really matter (with a large safety buffer, of course)

[big_zop]

Also on your car JZA, wouldn't a stock pump, feeding a bigger pump eventually run dry, with continued hard driving? eg 80l/hr pump main feeding 300l/hr pump in surge if you were pushing hard i'd imagine that eventually the surge tank would be dry...but i've not had much to do with fuel systems, so this is just a guess

That is not what happens when you are no longer using the pump to supply fuel pressure. So by reducing the load on the pump, it is able to supply more than it is actually rated for (which those numbers mean nothing unless you have a pressure rating as well). As for actual flow figures, I have not seen any testing to prove this but this is what my research has indicated.

Draven, i think you missed the point that a surge tank is meant to provide a steady source of fuel where the pickup in a large tank (is. stock fuel tank) would be dry in high g-load situations - and while you and JZA70 R may have enough power to move the fuel enough to uncover the pickup in a straight line, cornering is where most of the fuel surge will occur. But the result is the same, that the surge tank must be able to supply enough fuel for the time that the pickup is unable to supply fuel by starvation.


Though, I would probably upgrade the factory pump more for reliability than increased flow.

[Draven]

oh, totally agree. prior to fitting surge tank the only place I got surge was coming out of the fish hook at WP, but was more addressing the "eventually run dry" concern of the post.

[JZA70 R]

Also on your car JZA, wouldn't a stock pump, feeding a bigger pump eventually run dry, with continued hard driving? eg 80l/hr pump main feeding 300l/hr pump in surge if you were pushing hard i'd imagine that eventually the surge tank would be dry...but i've not had much to do with fuel systems, so this is just a guess

do the math for how long it takes to drain 1L of fuel @ WOT (800cc / 400rwkw) then find out how much more flow (or total) the oem pump supplies to the surge tank @ 0 psi load, and factor that in for say 50% of the time WOT is applied (simulating complete starvation of the pickup for half the time WOT is in effect). Then find out how many L/minute of fuel is returned to the surge tank from the return line and i think you will find its near on impossible to run out of fuel with this configuration and hp requirements in realistic and real world driving/racing applications... This is just what ive come up with and may be completely incorrect but given the success of similar fuel systems I think im not far off.