39lb vs 60lb injectors w/vortech

[serialheroes]

what are the pro's and con's with using each type of injector?

i am in the process or installing a vortech tuner kit w/o cooler.

it is a stock motor with longtubes.

Thanks
Ryan

[JimsZ]

How much power you really wanna make? 39lb should be good to mid-upper 400's and are alot cheaper! Now if you're going for 600 hp obviously 39's wouldn't work.

I would also think idle and lower rpm the 39's would be more stable than the 60's with a better injector flow (ie better streetability as on longer, but shooting less fuel during that time) but not positive about that

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[serialheroes]

with it being a stock motor....i've read just about everywhere that 450 rwhp is about the max until its forged.

[Saltyweasel]

Originally Posted by serialheroes

with it being a stock motor....i've read just about everywhere that 450 rwhp is about the max until its forged.

Quite a bit of debate about that. A lot of people say 450rwhp and a lot of people say 500rwhp with a good tune is safe. The tuner who did my car said he has done a few 4.6L 4v's that were 500rwhp and they never had a problem with them.

[rcodemach1]

I ran the 39 lb injectors previously with a Vortech at 10-11 psi on a stock longblock (I'm also running a 90mm LMAF). They were great on driveability and mileage and I had no problems tuning for them myself. I am running 60s now though, and it runs OK but I have not really gotten the tune dialed in yet.

The car used to run completely like stock when it had the 39s. Possible they were on the edge at WOT, although I can't say what the duty cycle was in my situation. I was more focused on the fuel pump duty cycle which has been OK running Cobra pumps and upgraded FPDM and wiring.

Current setup is 8-10 psi, minor port work in the heads, '99 Cobra cams, and longtube headers. Runs OK but not yet fully tuned...inside of tailpipes are black, LOL.

[Chances50]

I have 80's and my car drives like stock.

[Krashdavus]

I used the Ford Racing LU-47 injectors. I'm running a non-intercooled V2-SCi trim s/c. The injectors are are a direct fit, and I've got no fuel issues (with a Focus SVT fuel pump). However, I'm struggling with detonation. So we had to go to a conservative tune till I can get a meth/water injection system installed. Only made 370rWHP tuned in about 85F weather. Fuel trim a WOT, was about 12.2:1. I got a good deal on my injectors on EBay. NIB for $225. Blue Oval Industries has the best price on the LU-47's. $250/set, free shipping.

[rcodemach1]

Good info about the injectors. I've been curious about those.

I've had decent luck running non-intercooled but I also want to go with meth/water injection soon. Have you logged the fuel pump duty cycle and how much timing are you running?

Originally Posted by Krashdavus

I used the Ford Racing LU-47 injectors. I'm running a non-intercooled V2-SCi trim s/c. The injectors are are a direct fit, and I've got no fuel issues (with a Focus SVT fuel pump). However, I'm struggling with detonation. So we had to go to a conservative tune till I can get a meth/water injection system installed. Only made 370rWHP tuned in about 85F weather. Fuel trim a WOT, was about 12.2:1. I got a good deal on my injectors on EBay. NIB for $225. Blue Oval Industries has the best price on the LU-47's. $250/set, free shipping.

[Krashdavus]

Can't address the fuel pump question since I have no way of logging the data. Does the SCT scan tool have that capability? I know the GM Tech 2 does.

I found out that the SVT Focus pump doesn't like it when the fuel level is below a quarter. It will suck the basket dry on an aggressive tip in, which will give me a stumble. So I'll have to watch the fuel tank level from now on.

Base timing is 12 degrees. Hope to get more with my meth/water injection kit. I just purchased a Devilsown from a tuner in Wisconsin. I'm going to tap into the washer bottle, since I never (hardly) use it.

[Dan03mach]

The only difference is that one will be able to make more power then the other. They both will drive like stock with the correct tune.

[rcodemach1]

I think all the recent SCT programmers can datalog in conjunction with a laptop 'puter. You download Livelink to your laptop and once everything is communicating with the car it will store the parameters that you have selected.

It's been awhile but I will be doing this again very soon. I just got mine running again tonight with the Vortech back on the car and LT headers. I'm running 60 lb injectors and a 90mm LMAF. Timing is about 13 degrees in the timing table at higher loads. I put together a base tune and the car fired right up and idled fine. Once it's back on the ground and driving we'll take a look at the fuel trims and see if it needs some adjustments to the MAF curve. This injector and MAF combo have been run so often that the base value files for them in the SCT tuning software are probably pretty close right off the bat.

As for the pump in the stock basket, that's always been a little dicey. You can put a 3/4" hole in the side so it doesn't drain the basket but without a doubt you'll have to run a 1/3 to 1/2 tank minimum after that.

I'm running a Cobra tank and pumps for the second time and each time it's been completely trouble free. I have a modified FPDM and wiring still in the car from my experiments with single pumps. I never could make that work. Based on datalogging it always hit 100% duty cycle around 5,000 rpm or less. I have a very slight crimp or ding in my fuel line near the filter so that could be a factor, but it doesn't seem to limit the Cobra pumps.

Originally Posted by Krashdavus

Can't address the fuel pump question since I have no way of logging the data. Does the SCT scan tool have that capability? I know the GM Tech 2 does.

I found out that the SVT Focus pump doesn't like it when the fuel level is below a quarter. It will suck the basket dry on an aggressive tip in, which will give me a stumble. So I'll have to watch the fuel tank level from now on.

Base timing is 12 degrees. Hope to get more with my meth/water injection kit. I just purchased a Devilsown from a tuner in Wisconsin. I'm going to tap into the washer bottle, since I never (hardly) use it.