Fuel System Upgrades for Blow Thru carb with Turbo's

[Scott Liggett]

I'll be installing a twin turbo set up very soon. I need to start upgrading the fuel delivery system for that. I'll be running a blow through with a carb and hat. Anyone had experience with this? Also, I'll be keeping the boost down below 8 psi.

I currently am running the factory 3/8 hardline fuel line to an Edelbrock Victor pump without a regulator.

[TC]

IMO I would swap out the fuel line for 1/2" and run a A1000 pump with a carbureted by-pass regulator that can be boost referenced.........This is pretty much exactly what I'm going to do with the MonteCarlo when I put the twin turbo motor in it........

What brand blow-thru carb are you going to use??

[dieselgeek]

Don't get an A1000 if you're going to run only 8psi - you'll just overheart the fuel, wear out the pump prematurely, etc.

I'd have to question the use of two turbos versus a single in this application as well - plumbing twins is a little easier (no exhaust crossover) but then you have to double-down on wastegates and blowoff valves (you can maybe skip the BOV on 8psi but will that screw up the carburetor?).

And as always, I throw in the plea for EFI because it'll be a heluva lot simpler to tune when you get tired of 8psi. Every time you step up the boost on a blow through carb, you're very likely to have to go back to the drawing board on tuning. I don't hear this "on the internet" but every single blowthrough car I know at our local track has nothing but issues and they're always saying "yeah, well, it'd be faster if it was tuned"

[Orange65]

Sounds like you will need a pump at least capable of 8psi+what ever you intend to run for fuel pressure unturbo'd. The flow rate will depend on your expected HP. A boost referenced regulator will be required as well. As for the 3/8" line- that may be big enough, again depending on HP. As for a return style vs dead head regulator- a return style is easier on the pump, but you will have to plumb a second line to the tank.

Fairly bland reply, but if you are like me, you will do a lot of price shopping before choosing what to buy. If you find an inexpensive boost referenced return style regulator, let me know.

[CDMBill]

I think I'd work backwards from the carb. Scott, if you haven't met the Virbancic Bros. and been to the Carb shop you should make the trip. Bob and George know the blow thorugh carbs as well as anyone and they are in your backyard off Philadelphia and Vineyard at the 60. A boost referenced regulator is table stakes and the Aeromotive guys make a good one. Talk to Brian and then call Jesse.

Given the inevitable 'if some is good, more is better' aspect of boost and power generally, building a fuel system for the long haul makes sense to me, even if you move the hard pats to another car. While an A1000 is a bit of overkill at this stage I can't fault it as it has been so reliable for me, but talk to the experts.

At 8 PSI the carb doesn't have to be crazy and you may be able to do it yourself. Be sure you can get enough fuel through the needle and seat.

[Scott Liggett]

An A1000 is overkill for a 700 hp motor.

[TC]

An A1000 is overkill for a 700 hp motor.

Aeromotive rates the A1000 at 1200hp for boosted motors...........It maybe a little over kill, but it does leave room for growth......

And don't listen to DG's fear mongering, he has no clue, I'd bet half the guys on drag week run A1000 pumps.......I mean Aeromotive is the official Fuel System of DragWeek..........

[dieselgeek]

And don't listen to DG's fear mongering, he has no clue,

Guess what happens Alex when you over-pump a fuel system? the fuel temp goes through the roof - the tuneup gets thrown off. Not good especially for a carb'd engine. I've worked on likely 100+ A1000-equipped cars. Aeromotive has a (expensive) "fuel pump controller" that slows down the pump for extended street driving but about half the people I know who run it, have issues. CDMBill runs one and it works great for him.

I'd bet half the guys on drag week run A1000 pumps.......

How much are you willing to bet? I'll wager it's more like 5%-10%. How many cars in Daily Driver class run an A1000?!? that's 90% of the cars on DW right there.

I mean Aeromotive is the official Fuel System of DragWeek..........

And isn't Pennzoil or some other junk is the official oil of NASCAR!! we should ask Warp Speed if Hendrick engines run Pennzoil. ;-)

[Matt Cramer]

Is this the Victor mechanical pump or one of the Essex built electric pumps?

An Aeromotive "700 hp" or SX 18208 would be about the right size; combine it with a bypass type regulator. I think the Edelbrock pumps would be either an SX 18208 or the larger 18203.

[TheSilverBuick]

I'd be asking what Squirrel runs in his '55, match that and call it done. Reliable and proven. Only difference is you'll have to boost reference your fuel pressure.

[Bamfster]

Stupid Q time ....

Do you still need a boost referenced regulator if the carb is in a sealed box at that boost level?

[Beagle]

I'd bet Squirrel is running a mechanical... as electro-genius as he is, the cars are all pretty mechanical. Can't you drill out and tap the mechanical's atmospheric vent side for a boost signal?

Holley's Dominator electric pump is actually two pumps and can be individually controlled, Hobbs switch maybe.

[TheSilverBuick]

Stupid Q time ....

Do you still need a boost referenced regulator if the carb is in a sealed box at that boost level?

Yes. The needle and seat only want around 5-7psi typically, and at WOT the pressure usually drops to 2-3psi, so if pressure in the box exceeds the fuel pump pressure then it'll start pushing air into the fuel line (that's outside of the box). It will lean out and do bad things.

For 2 carbs and ~700HP, I'm pretty sure he runs an electric pump.

[TC]

I may think a bit different than the rest of you on this, but if I was making 700hp I definitely wouldn't be running a fuel pump that is only rated at 700hp.........For one the pump will be working at its max capacity, which means it will be pulling its max amps on the charging system, plus pulling max amps makes the pump run hotter........... With a pump like the A1000 it'll be nothing to move the amount of fuel you need for 700hp and it won't be laboring the pump at its max capacity.......

Also this idea that an A1000 will heat your fuel is being way overplayed, fact is all electric fuel pumps will heat the fuel to a certain extent, so don't think just cause you get a smaller pump it's not going to heat the fuel..... I mean if your really worried about that, you can always get an inline fuel cooler.......

But then Bill said he's ran an A1000 for years without a problem..........And at 5-7 psi that pump will hardly pull any amps, basically it won't need to work as hard at creating the pressure like it does in an EFI setup where the pressures are 10x that.........

[dieselgeek]

I may think a bit different than the rest of you on this,

Probably because the "rest of us" have actually installed a fuel pump on a turbo engine?

but if I was making 700hp I definitely wouldn't be running a fuel pump that is only rated at 700hp.........For one the pump will be working at its max capacity, which means it will be pulling its max amps on the charging system, plus pulling max amps makes the pump run hotter...........

You do realize that 700hp turbo engines spend 99.9% of their run time NOT making anywhere near 700hp? Unless Scott plans on building an engine to run an irrigation pump or stationary generator? Pumps rated to 700HP will support 700HP continuous with room to spare. This is how fuel pumps are rated, FYI. But you already know this right?

With a pump like the A1000 it'll be nothing to move the amount of fuel you need for 700hp and it won't be laboring the pump at its max capacity.......

Wrong! You have this completely backwards. Bigger pump means more GPH flow at a given pressure - more flow THROUGH the regulator instead of into the carb or fuel rails means MORE heat applied to the fuel temperature.

Also this idea that an A1000 will heat your fuel is being way overplayed,

How many engine have you monitored fuel temperature on - what engines were thy and what were your results? You've probably done more than me, I've only done it on maybe 15 cars... so your experience must trump mine, let's hear all about it please Alex.

fact is all electric fuel pumps will heat the fuel to a certain extent, so don't think just cause you get a smaller pump it's not going to heat the fuel.....

Wrong again.

If that's true, why would Aeromotive make a "step down" controller that reduces pump speed significantly under use? If what you are claiming is true - that a pump draws hardly any amps at low pressure, then why does Aeromotive recommend pump controllers for the street? Apparently you have more experience with fuel systems on running engines than Aeromotive does? I don't know about the rest of you but I cannot wait to hear all about it and learn from TC.

But then Bill said he's ran an A1000 for years without a problem..........

WITH a Aeromotive Pump Speed controller!