samdogmx

iTrader: (14)

the thing with running the higher base psi is you have to have a damn good pump & regulator. But if you want to running higher pressures you can get away with less injector.

On my car I just went ahead & bought 120# injectors, they only see about 70-75% DC on E85 with a 50psi base 22 pounds of boost.

LT1RAY

iTrader: (21)

Let's throw some math to all of this.

80lb/hr injectors x 8 injectors = 640lb/hr
640lb/hr / .65bsfc (gas) = 985 crankshaft hp
E85 requires about 30% more fuel
640lb/hr / .845bsfc (E85) = 757 crankshaft hp

Now these injectors (deka 80's) are rated at 3 bar, so at 4 bar they flow around 92lbs.

92lb/hr injectors x 8 injectors = 736lb/hr
736lb/hr / .65bsfc (gas) = 1132 crankshaft hp
E85 requires about 30% more fuel
736lb/hr / .845bsfc (E85) = 871 crankshaft hp

Forcefed86

iTrader: (4)

Those are good rough estimates when planning to purchase injectors. Though the hi-Z 80# injectors claim 80lbs at 42 psi. (3 bar would be 44psi). I'm all for larger injectors if you can afford them. Hard to get a hi-z above 80# for under $400 though. And many use the OEM ECU so low-z aren't really an affordable option. I'm not saying it's for everyone, just that it's an option. I run Low-z 120's on an aftermarket ECU so I don't have to run a massive amount of pump.

It's been proven through real world testing though that the Hi-Z 80's can make much more than 871 crank hp. Both by a dyno and by weight VS trap speed. Of course this was also done above the suggested 80% DC of the injectors. I've gone in the upper 90's and even static on injectors time and time again and never had a hiccup.

Going by weight and trap speed he was making 930ish WHP. Thats 3 intank 255's -10 to the regulator, -6 to the OEM fuel rail. You can argue numbers on paper all day long. The fact is, it's been done.

HexenLord

Yes skinnies made much more power on E85. He was also pushing 6 bars of fuel pressure.

Forcefed86

iTrader: (4)

No... the injectors only see 4.6 bar. The rest is cancelled out with manifold pressure and the rising rate FPR.

According to the calculator I used the 80's flow like a 101lb injector at 68psi. Or about 1050cc.

8 777cc injectors
.55 BSFC (.65 seems a bit over shot if you ask me)
99% DC

can make 1075 FWHP

777cc X 30% for E85 = 1010cc

http://www.witchhunter.com/injectorcalc1.php

nxfirebird

iTrader: (1)

you must be new at this game!
stock lines, rails, with 80's and 3 - 255's have made 800 plus on about a half a dozen combos around here.

if your on e85 and I were you i'd be turning my base pressure up to about 60 lbs and see what it will do.

1BadAsZ

On a 5.3 (iron 347) would 8.5-8.8 be too low to drive around on in order to be able to run pump gas? Or should I keep compression around 9.1+ and just run race gas on track days

Forcefed86

iTrader: (4)

No. I drove my 7:8:1 Gen1 383 SBC (iron headed, mild cam... nothing fancy) on the street in a 4000lb Gbody It still went 13.6 NA. (On 87 octane!) My gen3 5.3 was 8.6:1 and it drove great as well. Don't be afraid of lower compression.

HexenLord

Most factory boosted cars are in the 8:1-8.6:1 range. My old SRT4 was 8:1. If a 4 cylinder can be driven just fine out of boost at 8:1, a V8 won't even sweat it. At best you'll be down 15-20 HP with a one point drop.

stevieturbo

I'd say anyone would seriously struggle to tell the difference in a slightly lower CR, especially if it's an auto where the box would mask a lot of things.

skinnies

iTrader: (33)

I've also been 159mph on street tires(mud and snow tires, not drag radials) in my mustang at 3340lbs(aluminum motor in it then) with 80lb injectors. We ran right at 100lbs of fuel pressure at wot with no issues.

We've also done quite a few other cars, have LOTS of street miles with 80lb siemen injectors and 800+ rwhp on e85 and no issues with them.

Sadly 99% of people never push a fuel system, they just read what someone on the internet told them they can't do, or listen to their "tuner or shop" who has never done it. Too many "experts" without any hands on experience anymore thanks to the internet.

Shownomercy

iTrader: (1)

Same turbo here, Gen 2 motor, and only 10psi with no meth etc

Off trap/weight should be mid 700hp, but thats moot since its an auto, point is, lower CR (mine is mid 9s) and 80# injectors on a 60psi base work fine.

I have a magnafuel big *** noisy external but it works.

fly boy_1

iTrader: (4)

Thanks for commenting, cars like yours are inspiring. So Stick with some 80lb injectors, what fuel pump/s do you prefer out of everything you've tried? I was planning on dual aeromotive 340's will those run that amount of pressure? I also have an aeromotive A1000 regulator for -6 lines, are you running the regulator before fuel sees the rails, or after? Stock rails as well?

skinnies

iTrader: (33)

I've ran stock rails in my rx7 without an issue, in my mustang I have a pro flo intake so I have aftermarket rails. Both I use the Mallory 4305M regulator, with stock rails we always run the regulator just before the rails.

I have ran triple walbro 255 pumps before at 90+ lbs pressure at wot, now I prefer the bosch 044 pumps.

Everyone gets afraid of going over 80% duty cycle, that is just a calculated number. It's not like it stops adding fuel at 100% duty cycle. Also we have NEVER had an issue running 100% duty cycle with the 80lb injectors, many many miles on them and never a problem.

AutomagicLS1

iTrader: (18)

iirc hasn't maxx pushed the 80's on e85 to 130% idc where it stops reading in hp tuners and it hadn't leaned out yet or just started to? i remember we had my 160's @ 118% @ hob

skinnies

iTrader: (33)

140-145% duty cycle is when it can't add anymore fuel

1BadAsZ

Were either one of them boosted? If so was it on 93 or e85? And if so what kind of power/times was it turning

Forcefed86

iTrader: (4)

The 383 had a blower on it and ran pump gas. It was a low 12 sec car with the blower (P600B) at 8lbs and 93 octane on a true radial. (huge heavy car)

The times in my sig below are the 8.6:1 5.3. E85 fuel.