Does anyone know what the redline is on the automatic 302's? My tach. doesn't have any red markings or indications as to what the redline actually is. I know peak horsepower comes @ 3800 rpm's, but that's about it. I've always wondered that, and I think it's something I should know.

 

The physical redline is about 5500 rpm, but there's no reason to go past 4250 rpm. The limits for the roller cam 5.0's is about 500 rpm higher for both physical and practical redlines. Also, the factory tach is not accurate. The higher the rpm, the more it's off. The factory tach always reads higher than the engine's true rpm. I have had numerous customers tell me the new tach I installed in their Mustang can't be right because they were "able to rev so much higher before". I have on a few occasions, with particularly difficult customers, hooked up the factory tach, the new aftermarket tach, and my Fluke 88 set to RPMs at the same time for comparison. The AutoMeter tach and my Fluke 88 are usually the same, while the factory tach is high. The difference is often 1000 rpm or more at redline.

Take care,
-Chris

 

PKRWUD,

Thanks for the response. This makes me wonder then, why I've never been able to rev past 4000 rpm's according to the factory tach. Not that I'm trying to blow a head gasket or anything, but even in Park, I haven't reved past 4 grand, let alone in Drive. I don't know if my ECU won't let my engine get past 4000 or if my engine is just not in very good shape (but I doubt that's the case. It's newly rebuilt). I always suspected that 4200 was the redline since I could never quite rev that high and the peak hp comes at 3800 rpm. Has anyone ever taken their engine to 5000 rpm? Just curious if it's possible.

It's good to know that my speedometer, my odomter, and now my tachometer are all off!!! lol...

 

im in the same boat as you on that one! as far as revving the engine, the farthest ive gone is 5000, but thats 5000 according to the factory tach.

 

First off, I should clarify that 80% of the Fords that I have experienced the tach accuracy problem with were Mustangs, and up to 3000 rpm, they were pretty close. The higher they went, the more they were off. This was particularly true for sweeping action (like floor it, shift, floor it, shift). I would often rev it to what the factory tach said was 6200 rpm, but what was really 5000 rpm. For maintained cruising, the tachs are more accurate.

Okay, with an FIPK, and your exhaust, you should be able to reach 4000 rpms easily. The heads are extremely restrictive, but that's why the practical redline is 4250 rpm. With freer flowing heads, the practical redline goes up considerably. Still, you have eliminated the main restrictions other than the heads, and shouldn't experience any trouble getting there. The 4.9L in my truck pulls past 3500 rpm, but I don't ever take it past that point. Before I added the FIPK and exhaust, it peaked at 3000rpm. After the FIPK, 3300 rpm was where I shifted, but it still had more. After the exhaust, it went up to 3500 rpm. It was still pulling at each of those redlines with the various parts installed, but the "feel" changed rpm's. The "feel" at 3000 rpm stock went to 3300 rpm with the FIPK, etc. Make sense?

When you say you can't go to 4000 rpm, what do you mean? What happens?

Take care,
-Chris

 

PKRWUD,

Well, if I stab it right off the line, my rpm's will go up to about 3800 before my tranny shifts into 2nd. Then, my rpm's will go up to about 3500, maybe 3700 if I'm lucky before my tranny shifts into 3rd. From there, I could have it floored, but with my tires and 4.10 gear ratio I guess, my top speed is around 90-95 mph, which is roughly 3900 rpm in 3rd gear. Then, I can't go any faster unless I'm going downhill, but I've never tried that. As far as just putting it in Park and revving it, my foot goes all the way to the floor, but my revs only go to 4000. I don't know if it's physical or psychological (not wanting to hurt the engine) but of all the times I have floored it, my revs' have NEVER gone past 4100 rpm.

In a nutshell, my tranny always shifts before I can ever get to 4000 rpm's and even in 3rd gear (in Drive), I don't think I can go fast enough to get past 4000 rpm's. Perhaps a pair of aluminum Edelbrock cylinder heads will cure that? Or maybe a Vortec supercharger

 

What about if you shifted manually?

Anyway, what you need more than heads is a chip for the ECM. It will change the shift points, and get you more rpms when you need it. I had forgotten about that. Move a Superchip to the top of your list.

Take care,
-Chris

<EDIT>
Nevermind. I was thinking after I hit Enter that you had said something about having a chip on order, and I just saw the other thread, and remembered why I thought that. That will make a big difference.

 

I'm looking forward to the moderate power increase of the superchip, but one thing it will NOT do for my truck is increase the shift points. Unfortunately, the AOD is not an electronic transmission like the E4OD, so the shift points cannot be reprogrammed. The AOD is mechanically controlled, so the only thing I can do is get a shift kit which btw I well get later rather than sooner. A student only has so many funds, but perhaps in a year I will make beefing up my tranny a priority, certainly BEFORE my engine swap.

The thing I really hate about my tranny is that it shifts into 3rd much to soon. Going into second is fine, but if I could just get a little more out of 2nd when merging onto the freeway I would be in good shape. But I go into 3rd gear at like 40-45 mph and it takes a while before I can climb back into the higher hp band again. Eh, maybe I better put a shift kit on my Xmas list this year!

 

With the AOD I think you can adjust the vacuum modulator to change the shift points. You adjust it with a sdcrewdriver.

 

Wow. My bad. You're right. Guess I was thinking you had the E4OD, although I know you have the AOD. Too many different threads. I need to go work on the Sprint car.

A shift kit is always a fun addition.

BTW, you never said what happens when you shift manually.

Take care,
-Chris

 

Anytime I shift manually, my tranny will downshift. If I'm in OD, and I manually put it into Drive, it will downshift to 3rd gear. If I'm in Drive and I manually shift into 1st, the tranny will downshift into 1st gear. I've never tried going from OD to 1st, probably because my engine would blow up. But there's no way I can force my tranny to shift into 2nd like the E4OD. I don't have that option, though I wish I did. Maybe I could try going from Drive into 1st gear at like 25 mph, although I never felt comfortable doing stuff like that. But if I'm in first gear, there's no way my tranny will shift into 2nd so I might not know how high my rpm's can safely go until it's too late. But I suppose it could be done.

 

vavle body pressure has alot to do with shift points . i've adjusted my kick down to increase vavlebody pressure and it upshifts great . the downshift works good also.i can give it WOT getting ont he freeway and i shift @4000rpm. everytime . once i let my foot off it i am doing 85 @2400rpm in OD

 

Thanks for the suggestions. I'll have to include the valve body adjustments as part of the "etc." in my transmition mods.to do list.

P.S. What's involved in adjusting the kick down. Shifting @ 4000 rpm would be ideal!!! If it's not too much work, I might put a rush on that

 

"valve body adjustments"

That's what a shift kit is.

What I meant by shifting manually was upshifting through the gears. Light turns green, drop it in 1st. Accelerate until you want to shift, at which point you shift into 2nd, etc. Can you exceed 4000 rpms this way, and does the engine continue to pull past 4000 rpms? Does this give you any of the power you feel you've lost, or is the engine flat before 4000 rpms?

Take care,
-Chris

 

PKRWUD,

I can't do that with the AOD transmission. I have 1st gear, drive, and Overdrive, which is basically, 1st, 3rd, and OD. I cannot manually put it into 2nd gear. I've tried putting it into first right off the line, then engaging it into drive, but it usually goes right to 3rd gear. As far as engine feel, it certainly isn't flat before 4000 rpm's. I think that's an ideal shift point if I want to maximize my acceleration. It's just difficult to rev that high without my tranny upshifting into 2nd or 3rd gear. And in 3rd, like I said before I think my hp is the limiting factor, given my oversize tires, and poor aerodynamics. The reason why I want to increase my top end power so much is because that's where I noticed I lost the most when I got my 35's. Around town it's pretty much the same, but on the freeway I lost a lot of power.

I guess the best thing then would be to take a trip down to a transmission shop and see what they recommend. I've also heard that running full synthetic tranny fluid will keep my transmission much cooler, thereby increasing shifting performance. The downside is the cost, but that's also something I'm considering.