Engine What size MAF / injectors?

I have a very similar set up.

Stock bottom end
GT40 3-bar heads with smoothed intake and exhaust ports
Explorer upper and lower - internal EGR style
BBK 70mm TB and EGR spacer
C&L 76mm MAF (I had a 73mm on it and it doesn't seem to have made much difference)
C&L cone filter connected to hood scoop air feed.
19 lbs Explorer injectors (they have 4 nozzle holes vs stock Mustang single hole)
1.7 RR
Crower 15512 cam (dur.@.050 222/228, adv. dur. 282/286, lift with 1.7RRs .527/.544, 112 LSA)
MAC equal length shorty headers
MAC 2.5" Pro-Chamber with aftermarket cats added
MAC 2.5" Pro Dump mufflers with turndowns removed and 2.5" Flowmaster LX tailpipes
Innovate dual wideband (DLG-1 kit)

I'm a factory AOD car with AOD still in it (A9P ECU).


I have an Anderson PMS hooked up but not tuning. I am using it at this point as a monitor. What I have seen is at WOT, around 5000-5500 rpm, I was at 95% duty cycle on the injectors (wideband was showing 12.8-13.5). I think my horsepower level is 320-350 HP at crank (no dyno test to prove). Other than the calibration tube in the MAF, I have no tuning done to the system. Watching the widebands, the system seems to be behaving with no leaning out or over rich situations when driving under load.

I have just changed to 24 lbs injectors (because of the 95% duty cycle) but have not been able to test whether this has made a difference in performance. It does idle and run very well so far. Again only a custom sized calibration tube for the MAF to make it run. Hopefully some tuning in the spring/summer.

Depending on how you are planning to use your car, 19 lbs injectors for a street cruiser (that will not see high RPMs often) should work well with your combination and can simplify the conversion to MAF (stock computers, harness and MAF).

Just my personal experience and my 2 cents on your combination. Let us know where you go with it.

Five speed or AOD? With that simple of a setup,the stock cam works well,still punchy on the street. I hurt ALOT of feelings back in the day with a similiar setup.

Red50Fox said:

Monkey, it's an AOD tranny.
From the above it appears the 19lb (stock) injectors will be ok.
Thank you KRUISR for the detail.

I'm reading between the lines here but it sounds like I could leave the cam alone and go with roller rockers and still see a gain. If that’s true which would be better, 1.6 or 1.7? I guess same question on rockers if I do swap out the cam? Regarding the 19lb Explorer injectors, I did not realize they were 4 hole vs single, what's the benefit of that? Same amount of fuel just different delivery?

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I ran a stock bottom end,stock GT40 heads, Cobra 1.7 rockers,Cobra intake and usual bolt ons. Idled like a stocker and ran great. You'll want 3.73s minimum,and look at a Trans Go shift kit for the AOD. Will really wake the car up.

The 4 holes versus 1 hole gives a better atomization of the fuel. Essentially the same amount of fuel sprayed out in 4 finer streams instead of 1 larger one.

I have 1.7 RRs on 2 motors now, my current one and its predecessor. That engine was stock cam, stock heads, same intakes and injectors, same exhaust a modified Explorer 65mm TB that I believe was around 290-300 hp at the crank. It is original to the car with 244k km on it and was starting to blow blue smoke out tailpipe under hard acceleration (I still have the long block as pulled when I changed motors).

The 1.7s boost your stock cam lift up to 0.472 over the stock 0.444 and almost the same as the B cam (0.480).

Monkeybutt2000 said:

You'll want 3.73s minimum,and look at a Trans Go shift kit for the AOD. Will really wake the car up.

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I have 3.73s and a Lentech VB in an otherwise stock AOD (even the converter). Car is fun to drive, does very good mileage on the highway (better than my 2004 Escape).

Red50Fox said:

KRUISR, would you be interested in parting with the Explorer 19lb injectors?

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If you think you may be interested in 24#s, lmk.

Messing with the injectors is a waste of time and money.
The gains from the roller rockers will be negligible.
I'm not so sure an explorer intake has a 70mm opening.

The meter would however be worth it, as long as it's calibrated for the 19's.

One could even argue that the mass air conversion may not be worth the effort quite yet.
Speed density cars were always known to be slightly quicker than the mass air cars.

Once you change the cam, the conversion will be a must.
But as of right now, if it runs good, i may not mess with it.

2000xp8 said:

I'm not so sure an explorer intake has a 70mm opening.

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I read something from tmoss ... he said the Explorer has an 69mm opening. I had my upper off last weekend and can verify that it looks like 69mm. I have a 70mm TB and EGR spacer and you can just see the inside edge of the intake opening when looking down.

tmoss indicated that he didn't think the slight difference would make any difference.

Monkeybutt2000 said:

If you think you may be interested in 24#s, lmk.

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I already installed some 2 weeks ago. But thanks anyway.

Red50Fox said:

Hi all. Back to planning stages for the next round of upgrades for the 88 GT convertible.
I already have:
upper and lower gt40 intake
gt40 heads (#F1ZE-AA)
70 mm throttle body
BBK fenderwell cold air intake.

Thinking about:
mild street cam (303), roller rockers( what ratio, 1.6 or 1.7?)
MAF conversion.

My questions are:
do I need to, should I, upgrade my injectors? Currently stock at19lb.
do I need to upgrade anything else to accommodate the above.

Please let me know
Thanks

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I have the E303 cam in my '86, and I have mixed feelings about it. Sounds good, runs good, but jerks a lot at 800-1200 RPM. If doing again, I think I'd look for a different cam.