boost vs. fuel requirements

[93GTDIN]

I just bought an ATI procharger intercooled supercharger system and I was wondering what kind of fuel system I will need on my 1993 5.0. Any suggestions? Proven combos?

Will this work:

24 lb/hr injectors w/ mass air (70mm?)
190 lph Fuel pump

by the way, the kit says: 14 - 17 PSI boost, should I go bigger on the pump/injectors.

[speedytang]

The kit is for 19lb injectors and the FMU also can widen the injectors using this setup to make them think they are 36lb injectors. Now the best part of using a FMU is that you will not be over rich around town when out of boost but you will be pushing your small injectors because with the FMU you will be 80lbs on your fuel pressure guage instead of 40lbs which is the stock setting. Now for years I have pushed injectors to 125% cycle or more with no problems and many have also and then if you need a part it is alot easier to get a 19lb injector from a part store or trying to find someone to sell you a single 36lb injector. The only thing you should do is have a 255lph fuel pump in the tank. The Procharger kit does come with a pump correct? If so just install the pump and enjoy the fun.

[Unit 5302]

Here's another great thing. Having the right injectors for an application over 400-450hp is nice so that you don't have to replace the engine if 1 injector should fail. You can push injectors, but why in the hell would you spend 4k+ on that modification, and then skimp out on the injectors.

If you run at 14psi, 24lb/hr injectors should be fine, if you run at 17psi, you're getting towards the border line of wanting 30lb/hr injectors, but sticking with the 24's should still be okay. 19lb/hr injectors are NOT going to cut it. You'll be lean. 140psi on the stock injection cycle would be needed, and the safety margin on the stock injectors is exceeded at 100psi. That's under perfect conditions. If you step up to a bigger injector your computer will compensate injection cycles for around town driving. In other words, you won't run rich unless you get crazy with injectors. A 190lph pump will probably do just fine, but a 255lph pump has a safety margin.

[91GTturbo]

I'm fairly new to the forced induction game, but with that much boost, the fact you don't have forged pistons, I wouldn't run anything less than 30 lb injectors. You would rather be a little rich running more injector, than leaning out and melting a piston because you have to small an injector. 30's are the same price as 24's anyway.

I'm only running 6 lbs of boost right now, no FMU, 30 lb injectors and my car runs fine. I haven't had it on an wide band O2 to tell me exactly how it's running, but when I pulled the plugs they were golden brown in color, which I think is exactly what you want to see.

Like I said, I'm no expert yet, but I'm trying to learn.

[Paluka21]

Ah, in your other post you failed to mention the type of supercharger you purchased..no matter
I wouldnt skimp on the fuel system either. honestly an FMU is only a bandaid for small injectors. As said before I wouldnt go with anything less than a 30, maybe even a 36, and then when you have it tuned on a dyno you can let the tuner decide whether or not to keep the fmu or just ditch it. Thats the way I'd go, rather safe than sorry.
The procharger will definetly allow you to run safter boost w/ the intercooler and 14psi will be no problem at all.
BTW i ran an FMU w/ my 50# injectors when it was calibrated for 19-24's, saw like 100psi of fuel and the spark got blown out. W/ 80psi of fuel you will stand a chance of freezing the injectors, or blowning out the spark. do it right the first time
good luck
Dan
95 rio red cobra #2021

[Unit 5302]

30lb injectors will have a safety margin, but he's running with the rest of the engine stock. In that case at 14psi ATI indicates he'll make about 400hp or so. If other modifications are made, he'll probably want the 30lbers, but if he keeps it like it is, the 24lb/hr injectors would be what I would run.

Since the ProCharger will be intercooled, I would worry less about having hypereutic pistons.

[Paluka21]

well I can tell you right now that 24# injectors are going to be too small for that application and hp. He's not running aluminum heads so he won't gain quite as much hp as a modded motor will. However, its still 14psi on an iron headed car which will increase chances of detonation. Yeah he can run an FMU, but why band aid the car if he wants it to be reliable and not run high fuel pressure maxing out the injectors. I say do it right.
here is a breakdown of what seems to be the hp output you 'might' put out.
ok, 190hp to the tires stock, we assume, plus 14lbs of boost, which will at LEAST give you 175hp to the tires, maybe more after a good tune. So, now we're looking at 375rwhp x .15 for driveshaft loss is like 430fwhp which is NOT out of the question here w/ this setup. By NO means would I run 24# injectors, you would actually gain power by getting rid of an fmu and going to a larger injector. Sure he may have enough fuel pressure but you want the volume there too
24# injectors 100% duty cycle for a s/c'ed motor is 349hp (flywheel), 30# injectors is 436, and 36's is 523hp. As you can see, a 36# injector would benefit him best from this setup.
Heck, Im running 50# injectors w/o an fmu and was LEAN on the dyno, Larocca actually lifted at 4000rpm on the first pull. A/F ratio was around 14:1 !! This was with 50# injectors, 255 internal, ati external boost pump, 44psi fuel at idle, 7 degree base timing, kirban 1:1 regulator, and only 8-9lbs of boost. 50# injectors for 464rwhp and no fmu is what its at now and its a little rich, but its safe, thats where you want it!
if you have any doubts at all, call or email jimmy larocca, hes a great tuner and he's a pro. his # is 732-723-1111 , or visit his site at www.laroccas-performance.com. I would explain to him your gonna be running a 14# intercooler procharger that you are putting on a near stock motor, that you want pump gas, and be safe with, like an 11:1 a/f mixture on the dyno, cause on the street there is more of a load, and more margin for error. This is just my opinion, but I like things safe
Also, about that meter, you may want to think about going w/ a pro-m75 bullet, blow through, s/c'ed calibration. They work well w/ the ati prochargers, at least I havent had any probs w/ mine.
good luck, and as I said, I'd give jimmy a call at the shop, he'll get you squared away, he's a big procharger guy anyways.
Dan
95 rio red cobra #2021

[NO SLO PK]

As Unit mentioned, the 24s would probably work. But, it would be hard to go wrong with the 30s, and
besides, we know that long block won't be stock for too long, right? Also, if the kit doesn't come with an auxilliary pump, I'd suggest getting one...I'm using the T-rex, which seems to work okay. I'd also suggest a 255 in tank, as mentioned above.

[93GTDIN]

wow, thanks for all the help guys.... so I should go with a Pro-M meter, 36 lb/hr injectors.... awesome.. what type of ignition system would work best, and where should I put my timing. I really really dont want to run lean!

thanks again...

[93GTDIN]

i'm having trouble finding any 36's, will 30 lb/hr's work?

Also, I found a MSD/Vortech Boost timing master on ebay. Is something like this necessary for my application?

[NO SLO PK]

With the boost you intend to run, an MSD or equivalent spark box would be highly recommended. Without it, the spark will most likely get blown out...nothing really harmful except for an tremendous loss of power. If you're going to get an MSD anyway, the timing retard feature can't hurt. You could set your initial timing say around 14 degrees, and have the MSD pull it back to 9 or 10 under boost. Also, I've heard a lot of great things about the new iridium (sp) plugs. I'm trying them out next week...will let you know.

[91GTturbo]

Originally posted by 93GTDIN
i'm having trouble finding any 36's, will 30 lb/hr's work?

Also, I found a MSD/Vortech Boost timing master on ebay. Is something like this necessary for my application?

30's should be fine. I know people that run more than 15 lbs of boost with 30's, usually when its that high they have race gas mixed in, but as long as you try and stay conservative with your tune, you should be fine.

As far as the MSD timing master, I'm not familiar with this paticular product. You want something to provide more spark and something that will retard timing under boost. If the one on Ebay does that, I say go for it. Make sure the person your going to be dealing with on Ebay has enough positives that your not going to get robbed of your money.

I use a Jacobs timing master, mine retards the timing under boost, has an adjustment to set the initial timing, and has a rev limiter (which I don't need), and provides extra spark. Check MSD's web site and do a little research on some other brands.

Good Luck.

[Unit 5302]

Procharger indicates a 75% increase in power running on a stock engine at 14psi.

225hp x .75 = about 155hp. That's NOT to the wheels. Now 225+155 = 380hp at the crank. RWHP with his AOD is likely to be about 300. 19lb/hr injectors can support nearly 350hp, WITHOUT an FMU. Just with an AFPR and streching the injection cycle a little.

At ProChargers estimated gains, he'll be sitting at about 380hp, which would require a 4:1 FMU, or about 62psi on 24lb/hr injectors at the stock injection cycle. At 400hp, he'd need 69psi, or a 4:1 FMU. At 450hp (which is what ProCharger suggests performance may be at 17psi), he'll need 87psi, or a 6:1 FMU.

There are people on this board that are/have running/run near 500RWHP on 30lb/hr injectors. That's more like 600 crank hp on 30lbers.

In other words, the 24s will be just fine on an engine making what HP ProCharger suggests performance will be.

An FMU is NOT a band aid for fuel problems/injectors. It is a tuning tool that should be present on a forced induction car. If he runs a 6:1 FMU he's going to be completely fine, but like I said, if he's going to do anything in the way of mods, he'll be pushing the 24's.