Fuel regulator for supercharged EFI six?

[xctasy]

I'm running a stock EFI unit on my Cortina, and need to upgrade the fuel pressure regulator.

Instillation has 12 psi of blower pressure, and normal fuel pressure standard is 32 to 42psi via a stock XF EFI Bosch fuel pressure regulator.

For 12 psi of boost, the fuel pressure should go up the stock fuel pressure, plus anywhere between 1 to 12 times the boost pressure. Most supercharged vehicles do about 8 times the boost ratio on top of the stock fuel pressure.

If you have a 6 psi turbo, stock EFI fuel pressure goes up from the stock amount, plus 6*12. That's 42+72, or 114 psi. With 12 psi boost, its 186 psi.

Everyone with EFI turbos and superchargers looks to be using set rate Sard or Maltaplasi, or these,

the Vortec FMU .

Anyone here tell me what I should use?

 

[82F100]

In looking in the Aeromotive catalog their regulators will rise on a 1:1 ratio when referencing boost.

 

[xctasy]

Thanks. That fixed rate one might be better. Most of the time the boost level is the same from practically off idle to mid range. The concept of pumping 208 cubic inches into a 250 cube engine more of less assures that.

Vortec and other centrifugal blowers, and turbos, tend to have varaible boost. I've been told the fuel pressure needs to rise in a non-linear manner, and that too much at te top end of the boost range isn't a good thing.

One source said that it was better to start with quite a lot of pressure boost, and then downgrade the rate of growth. Apparently, that ensure the engine doesn't get over fuelled if youy are using a stock control module

(Like I am, I'm still using the vane air meter and stock injectors. Not many use the stock EFI systems because they'd rather spend $1500 on an aftermarket computer and then more on dyno tuning. I don't want to do that. I recon if the air fuel ratio is right under load on the road, that's better, and it still has to be able to lean cruise.)

I would really like to map the fuel delivery pressure to get the right fuel air ratio, rather than change the existing engine mapping. I was going to just use the stock EFI system at 42 psi, and then use two auxilary injectors to make up the short fall in fuel. A Delco set-up from a 4.3 V6 Caprice would be a good option.

Any other ideas on the fuel pressure regulator. Ones that solve the short fall in fuel delivery?

 

[82F100]

Maybe I missed it but have you given any thought to just a small step up in injector size or do you want to stay with the stock size ones?

 

[xctasy]

I'm still asking the question, but there are two basic options

I'm going to stay with the old fasioned stock 16 ohm injectors at present.

I can either


A) raise the fuel delivery pressure almost 90% to 70 psi via this 'mystery regulator'

or

B) order some Audi Quattro 346 cc/min 16 Ohm injectors (Part No 0 280 150 951).

Other options are running a lower 16 or 14 ohm Ford Motorsport injectors, such as those used on 3.8 SC's and GM Syclone turbo trucks. Modern Jap stuff is very low ohm, and options like 360 cc injectors from Mitsubishi Starions or our Diamante based Magna won't work unless the impedence is right.

If there was no heating in the blower, I'd have a potential power and torque growth of 81% over stock with 12 psi of boost. The problem is half of a Rootes blowers boost is then lost in heat, so I'll be lucky to see more than a 50% power boost. I'm not going to use an intercooler.

Fuel deliver at the injector should be proportional to what boost is actually getting into the engine. It's that old 14 parts of air to one part of fuel thing again. Adding 40 to 50% more air requires 40 to 50% more fuel pressure, or 40 to 50% more fuel through higher flow injectors.



Details below. All the best things are on the net!

http://www.telusplanet.net/~chichm/tech/injectors. pdf



Some basic working ranges for you.

Stock Bosch injectors by Ford run as little as 6.3 psi line pressure in 2.5's, to 33 psi in the 5.0 CFI Small blocks, to as much as 46 psi in Festivas. Mopar Turbo 2.2's go to 55 psi. 70 psi is seen as the maximum safe level.

Biggest injectors are the CFI Tempo HSC, at about 673 cc/min. Second is the CFI 5.0's with 483, then right down to a common 151 to 188 for the 90's smog era port EFI trucks

Basic ballpark figures are:-

The Bosch 0 280 150 215 items found on the 4.1 EFI Aussie Fairmont sedan are:-
214cc per minute at 100% duty,
20.4 Ponds per hour at 100% duty rating.
219 hp at 85% duty
Pressure is 36.3 psi,
They are good for 164 hp in stock form

The Bosch 0 280 150 766 items found on most pre 1990 4.9 EFI US F150 trucks are:
192 cc/min at 100% duty,
18.3 pounds per hour at 100% duty rating.
~200 hp at 85% duty
Pressure is 38 psi,
They are good for 160 hp in stock form

The Bosch 0 280 150 756 items found on the 3.8 SuperCoupe T-bird are:
321 cc/min
30.6 Pounds per hr at 100% duty rating
326 hp at 85% duty.
Pressure is 43.5 psi,
They are good for 210 hp in stock form.

 

[addo]

It's time you splashed on some bling. Get the biggest, fanciest one.

Remember this is all deductible!

 

[xctasy]

Tank you Adam-san.

This is not a tax write off yet. Not until I get something out there that people really want. It's a charted loss, with a hope of cash return sometime in the future.

No development, no money.

Best thing is that I can use junkyard parts, and not weep like Bob Hawke when I've been 'caught short'.

If I spend big on anti detonation measures (good regulator or injectos), then maybee I'll avoid this picture you posted a while back.

I can't quite figure out how to make them tax deductable yet unless I get a receipt for the $500 dollars the X-flow engine I'm using cost me. Hmm, maybee that means I have to blow the engine up!

 

[StrangeRanger]

Even with bigger injectors, you still need a boost-referenced regulator. As the manifold pressure increases, the pressure drop across the injector drops and the flow decreases, not quite what you need. If you buy injectors big enough to overcome the increased pressure, you'll have drivability "issues" running at near-atmospheric cruise, again not what you want.

 

[xctasy]

Hmm great!

The total calculated effective boost curve is

0 psi (leakage) at idle,
6 psi at stall (less than 1650 rpm)
8 psi at 2300 rpm
(Highway cruise, 60 mph in o/d 4th with my 3.7:1 gears is 2300 rpm which should be about 8 psi.)
12 psi from 4000 to 4500 rpm.
(Cam ceases to deliver power above 4200 rpm normally aspirated).
Hard Rev limit is 4500. Full fuel cut-off on sequential injection.

I think the fuel delivery pressure specs need to be
36 at 650 rpm idle,
38 at 1650 rpm,
40 at 2300 rpm,
55 from 3300 rpm to cut-out.

Is this likely to work okay?

What device do I use to do this?

 

[addo]

Sounds like a matter of blending injector dwell time and fuel pressure. Try that with a carb. The Vortec one is evidently a simple diaphragm - you can get a service kit. Then make your own out of some cheesy scrap. You need one of those Shop Smiths or whatever they're called.

The Super FMU is AUD$500 here. :roll: Dare you to buy one...

 

[StrangeRanger]

I've read and re-read Vortec's description of how their FMU operates and it just doesn't make sense to me. I'm not saying their part doesn't work, but the description doesn't seem to. A 1:1 regulator from Aeromotive or some other source seems the more intuitive device. It will maintain a constant fuel flow rate regardless of manifold pressure.

As to what injectors to use, figure on a BSFC for a blown engine of .55 lbs. per HP-hr and keep the duty cycle below 90%:

HP x 0.55 c (1/# of injectors) x (1/0.90) = injector size req'd. in lbs/hr

for 450 HP e.g.:

450 x .55 x (1/6) x (1/.9) = 46 lbs/hr. min.

Those injectors are going to have very different response characteristics from the stock (19 lb.??) units. You're going to need to get the computer chipped or re-flashed to deal with that or you'll have some issues with throttle response, surging, etc.

 

[xctasy]

Thanks. I've worked through that stuff you've got, SR.

Yeah, I was hoping to sneak up just a little without upsetting the EEC unit. Aint gonna happen.

I can see that in order to fuel up the engine enough using the stock system using the right lb/hr injector, I'm going to cause

a) the pulse signals,
b) the air vane,
c) and the sensors to work out side the environment Ford decided. Nasty electronics!

Stock injectors on the XF are very, very big, 20.3 lb per hr for only 162 hp and 245lb-ft. Earlier XE's ran 149 hp and 240 lb-ft. Ford really did put bigger injextors in there than needed .

I'd say 280 hp tops, or a minimum of 28.6 lb per hour is what I'd need with 12 pounds of boost, a 40% boost in pounds per hour.

There is a way to boost the fuel pressure or flow rate that much, but they are outside the correct duty rate. A set of 3.8 SC or Audi 200T injectors may be better (30 to 33 psi).

I've gone back and re read all the old Aussie x-flow Turbo articles I can.

23 years ago, Advanced Induction Technology (AIT) sold a turbo X-flow kit which was totally stock in the computer. It was refueled to 66 % for a 9 pound boost engine with no intercooler. It got 255hp and 390 lb-ft, up 105 hp and 150lb-ft from stock. 71 and 63% respectively.

To do it, David Inall at AIT just added a two injectors of about 430 cc/min (40.6 lb per hour), using a US made aftermarket auxilary fuel system. No ECM mods. It measures the Intake boost ratio via a sensor and then the rpm. Then looks up the fuel enrichment curve, and dribbles the right amount in. Just like any good old CFI Motorcraft unit on any old 5.0 80 to 84 LTD, or early 3.8 V6

I'm thinking I will leave the pressure stock, and then run two non return Motorcraft CFI 46 lb-hr injectors in the inlet tube below the throttle body, and upstream of the blower. The AIT system uses the stock air vane above the turbo, and the two injectors are upstream of the turbo.

I can get the exta 115 to 120 hp from that at 33 psi, and hook it into the fuel tank with just the old Ford LTD electric pump.

The injector supply can them be run off a secondary stock EEC unit. Idle delivery is then by stock CFI wet gear, and then I'll run off a a rsing rate fuel regulator to make sure it just dribbles fuel in at about 7 psi at idle and then grows to 36 psi or over 120 hp worth at wide open throttle.

Then the the subsidery system can be regulated, and all the stock gear stays stock. With the price of old EEC's and CFI units being junk, it looks a heck of a lot better than spending 1500 grand on a fuel aftermarket system which then requires very expensive high pressure regulators and other stuff to make it work.


It'll look around for something that suits the bill.

 

[addo]

If you're looking to develop marketable products using new parts readily available in the US, isn't it better to do your R&D with such? They will have a warranty, be easily sourced and replaced/serviced, will probably last several incarnations of destructive motor testing ( ), look professional in R&D progress pictures and external knowledge base should be good.

 

[xctasy]

Turbo, Supercharger, Nitrous and EFI Tech, the most expensive room in da house!

Development always needs to be done on a shoestring, working from the whole to the part.

Unlike houses, with existing structures, you'll never do anything if build it perfectly first up. The use of high quality components and very smart high end engineering is okay for an Saleen 5.4, but there is no way I'm gonna buy a component I don't need.

I read some delightfull examples of Henry Fords development of the V8 engines ignition system..in Edisons historic water mill, were the ignition teams was forbidden to use electricity! They used the water wheel to power the engine, then run the ignition tests.

Old Henry was sort of like Montgomery Burns in the Simpsons.


And speaking of Montgomery, Ohio George was the tightest wad on NHRA circuit, used out moded Ford parts and spent money where it counted. Adding a 427 SOHC engine to an old Willies Jeep and draping a Ford Mustang body on it just isn't right, but it sure worked for him.


Or the Holley guys who do carbs, Projection and systeMAX heads. Guess what engines they use to do there development work? 50 000 mile junkers from a junk yard. That's modern component development! Yeeehoooo!!!

I can spend about 3 grand on the engine management side, but I've found you learn nothing if you over capitalise before the project is a goer. Skunk works rules, k.o?

Except for the regulator.

That's my bling bling!

Now, what sort do I get that starts at 7 psi, and then rises to 36 in a smooth arc? Oh, and its gotta be expensive, shiney or anodised, and, um, American!