frcefed98

iTrader: (16)

My mototron 60lb injectors are at 80% duty cycle at WOT with a nice 11.5-1 a/f ratio....about how much hp would they be feeding to reach 80%?

The tranny is a stock 4L60E and i'm running through a 10 bolt, so the power robbing aspect of a TH400 and a 9 inch rear are out of the equation.

Any info or equations on how to figure out my lil question is greatly appreciated.
J

kp

iTrader: (34)

If the fuel pressure is around 55psi with 14psi boost and the regulator isnt boost referenced I would guess 600-625 flywheel HP. As far as rwhp, well you can try to figure that out but I say 530 or so rwhp.

All just an educated guess so I could be off +/- 100hp lol.

frcefed98

iTrader: (16)

No boost ref, fp was a steady 57-58psi through the pull.
I'm liking your figure of 530, but aren't these mototrons rated for 700hp? 100% DC being dangerous to run?

Being that the dyno didn't load the car properly and I take it to the track and the DC gets pushed to 90 or even 100% because the car is now loaded properly and i'm making some good power...i'd hate to run it lean and pop it...can't really pay attention to the ol laptop while powering down the 1/4mi.
J

ddnspider

iTrader: (26)

Hey Jer....i fooled around with a calculator i found online and its approx 750 crank hp...so figure 15% drivetrain and thats about 640rwhp give or take.didnt mean to contradict Kp,but thats what it looks like to me.

Edit....if your fuel pressure was ~57psi at the rails

HydroStream6

iTrader: (16)

I made 530rwhp on 42s at 100% DC (10.5:1)... going off that, I'd tend to agree with ddnspider, lower 600srwhp.

FWIW, I'm putting my 60s in tomorrow and am hoping for close to 700rwhp with them and a T70.

frcefed98

iTrader: (16)

Cool DD thanks for taking the time to do that. I was looking for a calculator to work that out online but wasn't successful.

650 "sounds" about right for 80% on 60lb injectors. I was just concerned that I'd be going lean at the track if I pushed em past 80% DC when the car was loaded
I really don't want to swap these injectors out for a low imp converter box and some low imp injectors....thought I was done on my fuel system.

I'll find a desolate stretch of road and do some 0-WFO runs to see what my DC's are on the street. Seeing the 60's go to 80% kinda freaked me out. I never thought I'd max those suckers out up at my elevation.

Hydro, I want a Red GTO Let me know how those moto's do with that new T70. Rear mount right? Sounds like a lot of fun

kp

iTrader: (34)

Unfortunately most people that make XXX rear wheel horsepower on a dyno jet doesnt mean anything when selecting injectors. I run 98% @ 65psi with 57lb injectors @ 6700rpm yet dyno under 600. If I put a 10 bolt in my car and M6 I would probably dyno 675 or so on a dynojet. So are my injectors good for 600 or 675 @ 98%LOL.

Not to mention the correction factor, if its high to the +side then the motor isnt really making that power on a dynojet. If you are making 700 corrected and uncorrected is 650 then which are the injectors really 'good' for .

Not to mention if he is running 15psi of boost there is that whole delta pressure thing and since he isnt boost referenced you can calculate everything at 42psi fuel pressure.

Anyhow, a 60lb injector @ 57psi is good for say 750flywheel @ 80%. Most I ever seen 60's go UNCORRECTED on a dynojet was 680rwhp and they were done. It was an M6 C5 and they were at 98% DC at 55psi (40psi with the delta) so that fairly close if you plug the numbers in. Plus there is a difference if you run the car at 12:1 a/f ot 11:1 a/f.

I have ran the 60s @ 90% + all day long..

kp

iTrader: (34)

You are nowhere near maxing those 60's out

Boost reference your regulator but depending on your pump setup it may it may not hold past 65psi. I have a set of high impedance 72s here and I'm going to try boost referencing from a 45psi base pressure so I can cut the low end flow down a bit. I am ay 95-97% with mine in cool weather @ 65psi. My dual 255s wont hold anything over 65psi so its done (I have 57lb injectors) right now.

ddnspider

iTrader: (26)

i agree w Kp get a FPR and up the pressure.

dynocar

FWIW my calculator came up with 640 SAE net FWHP using your numbers on a non boost referenced FPR for a supercharger application. If you were boost referenced, you would be at 740 HP.

ddnspider

iTrader: (26)

hes a turbo car there big guy

kp

iTrader: (34)

640 is close really, running @ 11.5:1 is a little rich IMO for max power and that will push the BSFC/duty cylce up which is why I gussed a little lower.

But like I said, base your choice on duty cycle and accurate HP data, in a drag race car going over 90% isnt going to be the end of the world. As long as the injector can deal with opening and closing with higher fuel pressure (and some deal with higher pressure better then others) there is nothing wrong with trying to raise the pressure with boost as long as your pumps can deal with it also of course.

My car never sees less then 85% duty cycle during a pass except for the first 30' or so, this one it 96% on a 6.17 @ 114mph 1/8 mile pass (no traction) on a 55 degree day (+500' DA). It is most definately maxed out on the injectors, if I had big enough pumps to hold 70-75psi with a 1:1 reference I could toss a couple more PSI of boost in the mix but thats it

frcefed98

iTrader: (16)

LOL, Man what good discussion this turned out to be.
As for what my built fuel system consists of:
Dual Walbro 255lph intank pumps, both on all the time.
-8an feed, -6an return from rails to the tank
CAS ADJ FPR, no boost reference(cause someone told me to leave it unreferenced because of tuning issues)
High flow billet rails
Mototron 60's injectors
All highflow fittings and Y's in the tank and throughout the system
Hot wired to get max voltage to the pumps, double relays yada yada yada

Maybe I phrased it wrong above but I was maxing these out was a worry when I say 80-84% on the dyno, without loading. Loaded on the street "might've" pushed em over the edge...that was my real concern.

Boils down to logging runs at the track with the slicks on going full tilt to see where i'm at.
I just want to be safe, can't afford to pop this one until next year

I agree with you Kev, a drag run isn't too hard on the fuel system, but "what if" I get into a high speed chase for more than 3 minutes...will my injectors like that huh, huh? It could happen JUST KIDDING
Thanks for all the great info KP and DD

kp

iTrader: (34)

After laying in it for 3 minutes straight injectors wont be your concern

You spent the money on a good motor so dont be too worried, be conservative and keep an eye on the wideband. I have no problem running over 12.5:1 a/f, got to make the power any way I can and if you arent running it on the edge at the track why bother but it takes a while to get to that point.

Turn up te fuel pressure to 60-65psi if you dont want to boost reference and just adjust your IFR to get your trims back in line. Most I can hold at WOT is 65psi no matter where I set the regulator. I have some 10ga wires going back to each pump as well as individual external grounds for each. I'm still on the stock 3/8 line but after looking at the size of the outlets on those 255s I dont think the line is killing me

See how much FP you can hold at high RPM/duty cycle, only way you get more out of the injectors you have. if you can get 10 more PSI that will help a bunch, but dual 255 pumps dont like being run at 65psi static for a long time, thats why the boost reference is nice. More then one way to do it, doesnt matter whats 'right' or 'wrong' just whatever works for ya

frcefed98

iTrader: (16)

Ok the boost reference will be hooked back up, but it goes against that certain someones advice I never really had my trims to far out of whack. Now I have a reason to put on that nifty red vacuum line I have in the garage

One day i'll upgrade to a nice Nasty N8 tank and hefty mega race pump...but i'll get a tranny first before that.

I can't really run it on edge at the track because if I mess up once and it goes my car will be down for another 6 months It has to be done safe, reliable and be able to do it time and time again...plus get me to work, home the grocery store...etc. Its my daily driver and it has lived life like this since I took owner ship of it One day when the wifey gets out of med school...then i'll be able to blow things up all the time...(dont tell her I said that lol)

Thanks Kp, I nominate you for "Mega MOD" here on tech for all the great info and help in more than one area, that you've passed my way
J

kp

iTrader: (34)

You have good pistons, they can take a little rattling, I'm just saying start safe and work your way up (or down).

Generally I see no reason to boost reference if your fuel system cant hold over 60-65psi at WOT with 60s. If you boost reference it the pressure still wont go over 65 anyhow so why introduce another variable to fail. I drive mine around all over at 65psi, but I probably wouldnt with dual 255s as a daily driver that high. Just because something works for me it isnt the 'best' way to do it, but at first its best to keep things as simple as possible. Log all your passes, spend some time analyzing whats going on, make changed one step at a time and done be hurried. Go on a track rental day or something you can take your time and do things the right way. Doesnt matter if you have a Pro Stock or a stock honda, thats how you get the best out of your parts. If you didnt have a dragstrip goal it wouldnt matter, bet when you have a target ET you have to look at the whole combination.

When I first took this car to the track it barely cracked 100mph in the 1/8 and ran 7.0x, needless to say I was a little disappointed since thats worse then my old P1SC SS did and it and the camaro weighed 100lbs more. But after spending some time with at several other dragstrips and not changing any hardware I drove the car to the same track 4 months later on a hotter day and ran 6.2x @ 110 through a hooker cat back and with DOT tires, thats what makes it all fun for me..

There a lot of people here smarter then me, I just have a lot of years of practical experience making things work to get down a dragstrip with a lot of different combinations. But mostly I'm a good guesser

frcefed98

iTrader: (16)

Hands on is the best practice and works well for me, guessing always helps....its cool when you hit a moment like...damn that was a great guess

Its going to be another fun year with a new combo(gotta stop changing combos so often). A lot will be figured out again

I'm just trying to eliminate varibles before I get to the track on march 5th, like fuel, tranny and boost settings etc. I'd just like to concentrate on tuning and suspension settings to reaching my goal of 10.99.

Nothing like trying to get prepared at the last minute

kp

iTrader: (34)

Its only a few weeks away for you. At least you have an engine..

Others have ran well with similar setups, I'm not that familiar with that exact turbo though. Main thing is to have fun with it, I wanted to do a combo change but I would have needed a trans brake, new converter, gear, better fuel system, aftermarket ECU and the cost of the turbo parts etc etc to run .5 to .7 faster and it just didnt seem worth it.

I do have a set of truck manifolds I got from PSJ's friend Ernie

frcefed98

iTrader: (16)

Truck Manifolds= DO IT!!!

Super easy except for the whole spending money for a turbo, WG, BC plus all the other upgrades you mentioned.....but with the turbo you can turn it up real good and go for the 1.5 faster...if your not pushing it to the edge why do it?

If my turbo is slower than my old procharger set up, it sure doesn't feel like it and its a ton more fun on the street....track time will be the kicker tho

slow

iTrader: (7)

If you don't boost reference, how does the pcm know about the injectors getting smaller under boost?

Ryan