If you have done a 5.0 HO conversion/swap you NEED a HO fuel pump

Reply #30 – May 29, 2007, 08:50:56 PM

Quote from: Sick88Tbird;150651

It's especially fun when you DON'T have a helper and a little more than 1/2 tank...it's amazing what you can do when you're doing it out of necessity.

yeah, try doing exactly that 3 times in one week like I had to. NOT FUN.:flame: and I didn't have this problem until I went back to a stock SO 88'tbird pump, so I would have to believe it is the culprit, since none of the other variables have changed for me.

If you have done a 5.0 HO conversion/swap you NEED a HO fuel pump

Reply #31 – May 29, 2007, 09:05:30 PM

Quote from: V8Demon;150650

You have to account for your fuel pressure at boost in a turbo or blower application. Again higher pressure = more injector flow, but less pump flow. TC injectors are still rated at 40 or so PSI when in fact at full boost they see more.

So, since the FP rises 1:1 with boost, I'd have to add maximum boost # to the total? Like this?

"Green Top" injectors = 30 lbs/hr + 22psi (T3) = 52 lbs/hr = 7.65 Gal/hr = 29.06 liters/hr
4 x injectors = 116.24 liters/hr

"Brown Top" injectors = 36 lbs/hr + 18psi (IHI) = 54 lbs/hr = 7.94 gal/hr = 30.12 liters/hr
4 x injectors = 120.7 liters/hr

"56"s = 56 lbs/hr + 28psi (SC50R) = 84 lbs/hr = 12.35 gal/hr = 46.9 liters/hr
4 x injectors = 187.8 liters/hr

Wow, that's a lot tighter, and definitely makes more sense. So a 155lph is pretty much required for any stock TC, and even a 255HP is barely adequate for me.

If you have done a 5.0 HO conversion/swap you NEED a HO fuel pump

Reply #32 – May 29, 2007, 10:08:25 PM

its called using a transmission jack. wussies!

If you have done a 5.0 HO conversion/swap you NEED a HO fuel pump

Reply #33 – May 30, 2007, 12:13:10 AM

Quote

So, since the FP rises 1:1 with boost, I'd have to add maximum boost # to the total? Like this?

"Green Top" injectors = 30 lbs/hr + 22psi (T3) = 52 lbs/hr = 7.65 Gal/hr = 29.06 liters/hr
4 x injectors = 116.24 liters/hr

"Brown Top" injectors = 36 lbs/hr + 18psi (IHI) = 54 lbs/hr = 7.94 gal/hr = 30.12 liters/hr
4 x injectors = 120.7 liters/hr

"56"s = 56 lbs/hr + 28psi (SC50R) = 84 lbs/hr = 12.35 gal/hr = 46.9 liters/hr
4 x injectors = 187.8 liters/hr

Wow, that's a lot tighter, and definitely makes more sense. So a 155lph is pretty much required for any stock TC, and even a 255HP is barely adequate for me.

BINGO! Now we're starting to get it! Just one thing though. Looking at the chart I posted, at 62 PSI a 30 pound injector would flow about 38 pounds per hour. You can't just add the pressure as you did. The actual formula is:

New flow rating = [square root of (new pressure /old pressure)] x old flow rating

Example:
New flow rating = [square root of (45 PSI / 39.6 PSI)] x 20.0 lbs./hr = 21.3 lbs./hr

You also have to take into account that a forced induction engine almost always has a higher BSFC than a N/A engine of similar size and power (I.E stock motor w/ a centrifugal blower vs. a H/C/I motor both producing equal peak power.)

Fuel requirement in lbs./hr = (Max HP x BSFC) / (number of injectors x duty cycle) Most OEM manufacturers like to keep duty cycle at .80 to .85

If you have done a 5.0 HO conversion/swap you NEED a HO fuel pump

Reply #34 – May 30, 2007, 12:32:30 AM

1) I was using 24# injectors in the 270 RWHP engine

2) I have a spreadsheet to calculate fuel needs - I estimate BSFC based on AFR (N/A = 12.5-13:1, blown = 11.5:1) & static compression

3) injectors still have exactly the same 40 psi across them even under boost (10psi example - 50 on top, 10 on bottom 50 - 10 = 40). Oops, you are correct that the pump has more backpressure, thus lowering flow potential.

4) I've maxed 36# injectors in my current setup - I logged 105% duty cycle (calculated based on pulsewidth & RPM) - that was something that caught my attention! :D (thus my current 42# injectors)

If you have done a 5.0 HO conversion/swap you NEED a HO fuel pump

Reply #35 – May 30, 2007, 12:46:24 AM

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1) I was using 24# injectors in the 270 RWHP engine

I figured you were using larger than stock.

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2) I have a spreadsheet to calculate fuel needs - I estimate BSFC based on AFR (significantly different N/A vs blown) & static compression

Can you send me that spread sheet?

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3) injectors still have exactly the same 40 psi across them even under boost (10psi example - 50 on top, 10 on bottom 50 - 10 = 40).

What size pump are you currently using?

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4) I've maxed 36# injectors in my current setup - I logged 105% duty cycle (calcualted) - that was something that caught my attention! (thus my current 42# injectors)

I'm running a 255 pump with 19's at 64 PSI (24.5 lbs/hr static flow). I'm 95% certain I go static at WOT and even at that pressure I'm most likely very close ro 100% duty cycle. The low speed driveability is just too good right now and she pulls like a raped ape up top with no lean codes. I tried to go bigger on the injectors, but she idled like poo. I attribute most of that to the MAF meter that I tried using (GMS sux!).

I opted to go with a C&L 73 mm setup for 19's instead for the time being. I plan on going bigger again, but it'll be properly dynotuned when I do so. It should happen sometime in July. I'd like to find about 15 or so hidden horsepower.

If you have done a 5.0 HO conversion/swap you NEED a HO fuel pump

Reply #36 – May 30, 2007, 01:00:29 AM

Heh, you got to it before I finished my edits - I am buttstuff about posting material that reads a certain way (properly) - lol.

I'll get you that spreadsheet - where to send it to? It's actually a modified sheet I got from the web somewhere - you'll like it - there are other tabs for doing blown engine calcs.

Funny, I was using a 155lph pump w/Boost-a-pump but I used a Mustang kit and the sock did not reach the bottom of the tank - thus I would uncover it at the track unless I had like 1/2 tank - very annoying. I also had a leak at the filler neck that prevented me from filling the tank - ever. I got a 190lph Cougar/Bird specific kit that someone provided a link to here (this is what makes a site like this great) and recently replaced the 155lph (anybody want the old pump?). Now I can turn down the BAP to about 20% and see no drop-off in fuel pressure (I log fuel pressure, boost, AFR & 16 other engine parameters using the TwEEcer).

If you have done a 5.0 HO conversion/swap you NEED a HO fuel pump

Reply #37 – May 30, 2007, 01:19:49 AM

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I'll get you that spreadsheet - where to send it to

Paul_Flockhart@hotmail.com

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I was using a 155lph pump w/Boost-a-pump

How is the B.A.P. kit? where does it mount? The reason I ask is because if this tranny ever goes, I'm throwing in a Lentech and some type of centrifugal blower will be used with my current combo to assault that new Lentech properly.

If you have done a 5.0 HO conversion/swap you NEED a HO fuel pump

Reply #38 – May 30, 2007, 09:45:30 AM

So my 255HP might not be enough for the 56#s? Argh!

I still need to control it all somehow too...

If you have done a 5.0 HO conversion/swap you NEED a HO fuel pump

Reply #39 – May 30, 2007, 10:27:43 AM

The flow would be 171 liter/hr for the 4 injectors using 6.5 lb/gal. At max fuel pressure your pump should flow at just around 200 LPH. You should be fine.

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I still need to control it all somehow too...

Explain....

If you have done a 5.0 HO conversion/swap you NEED a HO fuel pump

Reply #40 – May 30, 2007, 10:40:52 AM

I can't just plug the 56#s into the harness and hope the EEC knows what to do :hick:

I have a Kirban AFPR, and a Gillis Boostvalve, so I can adjust fuel pressure and boost along with base timing. I have no wideband or data-logging and still run 35#s (temporary) until the 56#s and something to control them go in. It's a toss-up between a TwEECer ($$$) or a Moates J3 ($). I want the new MSD Blaster EFI, but $1000 on a stand-alone is out of my league.

If you have done a 5.0 HO conversion/swap you NEED a HO fuel pump

Reply #41 – May 30, 2007, 11:00:17 AM

Quote from: Aerobird Motorsports;150761

I can't just plug the 56#s into the harness and hope the EEC knows what to do :hick:

I have a Kirban AFPR, and a Gillis Boostvalve, so I can adjust fuel pressure and boost along with base timing. I have no wideband or data-logging and still run 35#s (temporary) until the 56#s and something to control them go in. It's a toss-up between a TwEECer ($$$) or a Moates J3 ($). I want the new MSD Blaster EFI, but $1000 on a stand-alone is out of my league.

MegaSquirt

If you have done a 5.0 HO conversion/swap you NEED a HO fuel pump

Reply #42 – May 30, 2007, 11:04:33 AM

Seems like a nice piece. Here's the link:

http://www.msdignition.com/2007/blasterefi.html

The Megasquirt CAN be programmed to SEFI, correct?

If you have done a 5.0 HO conversion/swap you NEED a HO fuel pump

Reply #43 – May 30, 2007, 11:27:31 AM

Quote from: V8Demon;150725

Paul_Flockhart@hotmail.com

How is the B.A.P. kit? where does it mount? The reason I ask is because if this tranny ever goes, I'm throwing in a Lentech and some type of centrifugal blower will be used with my current combo to assault that new Lentech properly.

The BAP is nice. I mounted it just behind the rear seat under the rug in the trunk - real close to the fuel pump :) . I mounted the adjustment dial near one of the hinges in the trunk - I get looks from people who wonder what I'm doing when I open the trunk & turn a dial - it's kinda stealthy. It activates on boost and you can dial it in - since there is always some loss in the system, increasing pump voltage via BAP will actually let you tweak open loop AFR just by rotating the dial one way or the other. I don't like to pump more fuel than needed (just heats it up) so I added an RPM switch in series with the Boost switch so the BAP will only activate >3psi & >3k RPM (I also have the H2O injection triggered off this same setup. Works nice - when cruising all that is off and only activates if someone asks for it

If you have done a 5.0 HO conversion/swap you NEED a HO fuel pump

Reply #44 – May 30, 2007, 11:52:47 AM

MegaSquirt = no way

I suck at wiring and after adding up the $$$ of everything my combo needs to run, the TwEECer is cheaper. I'd like to keep the VAm or go MAF for now, but I LOVE the Blaster EFI as it's TRUE Speed Density, so I don't need to upgrade MAF's and there's nothing in front of the turbo.