Is It Time To Upgrade To 24lb Injectors?

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I've got a couple stretches of open highway on my way too and from work that I can't seem to keep my foot off the gas on, with 3.73's I'm over 4000rpm a lot and have had it up close to 6500rpms. At high rpms the car has plenty of power, will spin the tires when I drop a gear and floor it at 50mph and then chirp them again shifting up to 3rd gear. I have owned the car since it was new and it never did that before with the stock 5.0, not even with a 10 inch torque convertor.
There is no power at 6500rpm with a stock cam and gt40 iron heads (power probably stops about about 5500rpm).
Besides the rev limiter is 6250 so...

You will spin the tires at a 50mph roll when your stock auto trans drops a gear?
I think something may be wrong with your trans and it's slipping, you are probably about 200rwhp (yes that's two hundred) short for that to happen.
Most auto trans cars with 250rwhp couldn't spin bald tires in the rain at 50mph.

The things you describe are tough to do in an 11 second car.
You likely have a high 13 low 14 combo. Maybe 245rwhp or so possibly less since it's an auto.

I'd do as Dave suggest, get a 155lph pump and not mess with the injectors until you need to.
 
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The car does have a built trans in it with extra clutches, not sure of everything that was done to it but it came with a 10inch convertor when I bought it about 12-15 years ago, just had it rebuilt 2 years ago and the guy said it had extra clutches, a stronger (basket ? ) and the valve body had been changed, it went out on me down in Ohio and cost over $400 to flatbed the car home, I noticed metal specks in the fluid and that TC so after it was rebuilt I just put in one of my old stock TC's but it will spin the tires at 50, not smoke them, and chirp them again when it hits 3rd, low end sucks, won't hardly spin the tires at all from a stop but once it's above 2500rpm the motor pulls great. The 6500rpm is on the stock tach and we all know how accurate they are or aren't! because it seems so slow at low rpm I'm thinking low 14's on street tires. Once I put the higher stall TC in I'm hoping for high 13's............stock everything except 3.73 gears when new it was high 14's- low 15's.
Spinning the tires at 50 is only when I floor it and drop from drive down into 2nd gear, has happened a few time when I was coming to a light that changed from green to yellow, and when getting on the freeway after getting to where the entrance ramp straightens out..........I got on it once getting on the freeway and the back end went back and forth 3 times when I wasn't expecting it to so I don't get on it till I'm going straight now.

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You will spin the tires at a 50mph roll when your stock auto trans drops a gear?
 
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Just as a reference, I shift at 6500 on my stock tach. Verified on the dyno this is about 5500 RPM.

Get a shift light, and don't guess.

There is away to calibrate the tach so that it will be very accurate at high RPM, but the low and mid ranges are off calibration by several hundred RPM. I have done the calibration routine, but it takes a audio frequency generator, a frequency counter and an oscilloscope. I have all that and use it occasionally to troubleshoot other electronic problems.

The 87-89 tach has only 1 adjustment potentiometer, so you either set it to be accurate at low to midrange RPM or high RPM. Supposedly the 91-93 tach has two adjustment potentiometers, one for the high RPM and another for the low RPM. I haven't seen a 91-93 tach, so I can't verify that.

See more at http://www.stangnet.com/mustang-for...a-stock-fox-tach-to-be-accurate.805785/page-1
Be sure to read both pages 1 & 2 to get the full story...
 
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Stock HO Cam. The thing spins fine if you drop the lifter preload to 1/8 to 1/4 turn. After I did the heads I really noticed the dropoff at 4500-5k. Took down the preload and it made a world of difference up high AND down low.
When I set mine They went just over the 1/2 turn to get the proper torque setting, that is with the TFS valve springs and about 1/2 of them needed shims per the instructions from TFS. So from what you are saying I should back it off a bit to get better low end?
 
When I set mine They went just over the 1/2 turn to get the proper torque setting, that is with the TFS valve springs and about 1/2 of them needed shims per the instructions from TFS. So from what you are saying I should back it off a bit to get better low end?

I would definitely try that if I were you. Myself I'm using the Crane 1.7 rockers, and I was getting poor low/top end power, as well as alot of rocker noise at 3/4 to 1 turn of preload. After setting them all down to ~1/4 turn preload there was a noticeable power improvement AND the noise quieted down, despite everything I have ever read to the contrary indicating that more preload = quieter.
 
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I would definitely try that if I were you. Myself I'm using the Crane 1.7 rockers, and I was getting poor low/top end power, as well as alot of rocker noise at 3/4 to 1 turn of preload. After setting them all down to ~1/4 turn preload there was a noticeable power improvement AND the noise quieted down, despite everything I have ever read to the contrary indicating that more preload = quieter.
I have great mid to high rpm power and no noise, just not as much low end power, I assumed it was from the larger cc of the GT40 heads compared to the stock heads and only having a stock torque convertor in my AOD. I will be swapping out the stock TC for a higher stall which should get the low end back for taking off from a dead stop, if that doesn't help I'll try to take some preload off and see what that does.
 
Used to have a shift light. Got rid of it years ago. I honestly don't look at the tach running down the track, I just tend to feel the car out and shift when I think it needs it. I've even found when running cars with shift lights I don't use them. Seems to be working for the time being.