Hi,

I've just ordered an upgraded fuel pump as I am running very high boost on the stock fuel system apart from an HKS AFR and lots of NF!!

I'm still not seeing dangerous EGTs though.

Can I change the injector sizes from 380 to say 440 without confusing the cr@p out of the stock ECU or will I have to swap the ECU for a mappable jobbie?

Anyone done this?

The car is a 1996 UK by the way.

Thanks
Rich

 

Rich I don't know how well it would idle and cruise on the std ECU, but you would probably get good benefits from a Link by optimising your fuelling and ignition? Is this something you would map yourself?

 

Rich

How about an FSE rising rate fuel regulator to go with your new fuel pump ? I gained approx 20% more fuel by doing this.

Thats 20 % more BHP capability. 20% of 320 is +64bhp....which is nice

The bonus is that idle and cruise are not affected as the fuel pressure only increases with boost pressure.

Andy

 

The jump from 380cc to 440cc without changing the ecu is too much. The car will be very thirsty, idle bad, and generally go crap. I have done this while waiting on a new ecu. I just tried to see what it would drive like until the brain was sorted.

 

If you combined this with something like a Apexi S-AFC (which I happen to have!) and use that to reduce the fuelling to compensate? I would have thought that the ECU would then reduce the duty cycles on the injector.

In this case knock 16% off the fuelling across the board. Alternatively, you could do the same by increasing the fuel pressure for a more modest increase.

Does this sound feasable?

Paul

 

Yes that will work fine, but you should always reset your ecu then drive so the car can adjust the maps

 

Cheers Lads,

I suspected that there may be problems as John stated with idling etc. Wouldn't have the first clue about mapping a Link though. Takes me all my time to work the video

Andy,

Thought about an FSE boost valve actually, but I would have thought at 320bhp I'll be working the standard injectors to the MAX anyway so they'd be the weak link, so upping the fuel pressure wouldn't give that much of a gain would it? What size injectors are you using?

I think Pavlo's idea sounds feasible. Anybody tried this them selves?

Cheers

Rich

 

Andy,

Which fuel pressure regulator are you using?

How much base fuel pressure do you have?

How much does this pressure regulator cost and where did you buy it?

Thanks for your information
ric

 

I would not do what you ar suggesting for a second.
The change from 380s to 440s is enormous.

if you have to do anything, then dropping fuelling with a fuel controller across the broard is a little safer, and perhaps ok.

I dont know what submannz is talking about though. The standard ecu is programmed for a standard injector size and will not compensate on fuelling except when in closed loop mode at idle and on cruise.

On boost it references a map based on inputs from the maf and map sensor, not from feedback from the lambda sensor which is narrow band so not accurate anyway.

On boost you will bbe seriously over fuelling, and breathing mods on the standard ecu are already compensated for by the maf and map, so this will compound the problem as it is already asking the 380 to produce. The percenatge fuelling will be even worse on boost.

run rich and yuo get bore wash, removing your oil film by washing it away with excess fuel, this leads to piston pick up and engine failure.

Rather you than me!

 

Adam,

Is there any way around this fuelling issue without going the mappable ECU route or not?

Should I just uprated the fuel pump, increase fuel pressure and call it a day?

Exactly how much power should the standard 380s be able to handle?

Cheers

Rich

 

Rich, In my car (MY94 WRX) the standard 380 injectors and standard intercooler were only good for about 295 bhp. At this the injectors were running 99% IDC. This was on standard fuel pump and regulator though. Breathing mods were Blitz induction kit and straight through (turbo back) Scoobysport exhaust. ECU (standard one) was remapped by Power Engineering. 440 injectors and FMIC took me to 330 bhp but IDC was still 95%. I now run 550's with uprated pump (but std regulator) and IDC is down to about 85%. Sounds like an uprated regulator may be a good idea.

Stuart

 

Cheers Stuart,

Christ, 550s!! Didn't know you could remap the standard ECUs on earlier cars. Graham Goode told me you couldn't.

Did you experience any idling problems as described above?

I'm running 320+bhp on 380s (will know exactly what the figure is next week) so an upgraded regulator looks favourite.

Cheers
Rich

 

ive put a uprated pump on mine (well its on the bench waiting to go in) and fitted an uprated fpr... see fmic thread for pics...

David

 

Rich

I run 380's. My fuel pressure with std pump and reg was only 3.8 bar at full 1.7 bar boost.
The std pump just couldn't maintain the pressure. It 'should' increase fuel pressure from the base line of 3.0 bar in line with boost ie +1 bar boost (3+1) = 4 bar fuel. 1.5 bar boost = 4.5 bar fuel.

With the bigger pump and rising rate regulator, I run 3.2 bar static fuel pressure (that extra 0.2 cures a lean spot caused by induction kit) and, due to the rising rate, at full boost I now achieve 5.5 bar.

Flow is proportional to the square root of differential pressure
so increasing from 3.8 to 5.5 increases flow by 20%.
Yes the injectors are max'd out but they are just solenoid valves and they are cooled by the fuel flow so no problems there

Andy

 

Just read your question again

FSE supplied my regulator. Check out their website FSE Glencoe , make sure and ask for the 1.7:1 rising rate jobbie. Approx £100 after del'y n vat

 

Cheers for that Andy,

If it's good enough for you, it's good enough for me.
Now, where's my credit card gone?

Cheers

Rich

 

Rich,

I think the FSE regulator is probably the best way to go as well. I think that Andy.F is the proof here!!!

I will be interesting to see how you get on with it.

Cheers



Iain

 

Fuel pump on my desk, regulator on its way!

See you at 350bhp!!

Rich

 

Rich... If you need a bracket making or are going to make one have a look at:

http://www.scoobynet.co.uk/bbs/threa...D=89747&Page=9

I would also change to running a paralllel feed rail... (make sure all hosing that you use is Fuel injection hose as it withstands higher pressures.)
http://www.scoobynet.co.uk/bbs/threa...=89747&Page=10

Let me know if you need a hand or anything..

David

 

Whoh this thread goes way over my head!

I'll get my coat

 

upping fuel pressure is okay, but I would do it with a mappable ecu.

I think of it as a band aid kind of solution.

I would rather go for larger injectors and retains the stock fpr. You have done the wise thing and bought the fuel pump, so can be assured the fuel is there for the injectors to supply.

dont forget that raising fuel pressure will reduce the amount the pump can flow! you will be fine with a warlboro type pump, as it is ok for higher pressures.

 

Adam two words (well actually three)

Boring And Expensive

David

 

"dont forget that raising fuel pressure will reduce the amount the pump can flow!"

This is why the regulator is always fitted together with an uprated fuel pump. If the pressure is maintained at a higher level, the flow will be increase by:

squareroot(new pressure/old pressure)

If the injectors are flowing more, then the pump most certainly is too!

Paul

 

Disagree with David ! Mappable ECU's are not boring, I'd love one They are however expensive Can't justify one yet, not when I measured 375 bhp and 370lb-ft tonight on the std ECU and injectors.

Gimme more band aids love em !

 

375bhp! 370lbsft!

Jesus Christ m8! Well Done! Bet that feels RAPID.

I'm on the rollers Monday, so we'll see what difference the Walboro pump has made (not got the regulator yet - but it's on it's way).

What has given you the increase Andy, last time I heard, you were on 349. Which mods have you done since that?

Cheers Rich

P.S.

Glad that Adam raised that point actually about increasing pressure actually reducing the amount the pump can flow. Would not have thought about that, but now I've thought about it it's obvious! given that, would you want to raise pressure with the uprated regulator or lower it? Natural instinct says raise it to get more fuel in. God, this is confusing!

 

Oh yes,

David, if I need a bracket making, I'll give you a shout, cheers for that m8

Got to go now, my Bilstein suspension has just arrived!


Cheers

Rich

 

Front feed to turbo and scoobysport uppipe did the business, ooh and not forgetting my inlet manifold insulators and exhaust heat wrap

Yes increasing the pressure will reduce pump flow 'slightly' but as long as the FPR is still controlling things then the pump must have adequate flow as the excess is recircing back to the tank.

Andy

 

Fappin hell, stock internals too!

Although after we all blow our engines, I'm sure we'll find out the previous owner of Andy's car put an uprated bottom end in his engine....

Well done, but surly that's enough torque and power to get a *slightly* longer gearing?

Paul

 

Yea, gearing feels too short now :rolleye: 8 seconds from standstill and I'm in top gear. Have to drive with one hand constantly on the gearstick

 

My racing karts manage with only one gear and no clutch.....