AOD Torque converter question

[Black84]

I have a 1984 4x4 ranger with a V8/C4 combo, Im swapping the tranny out for an AOD. The C4 converter is too tight for the cam and the truck would fall on its face from a stoplight, plus it has a manual valve body, and Im kinda looking to get away from all shifting. Also Ill get better gas mileage with the AOD, as I will be using the truck as a daily driver.

Cam is a TFS Stage 1, power range is 2000-5500. I was thinking a 2200 or 2400 stall, but was told that due to it being a truck, I should goto a 3200 stall.

The AOD and transfer case are both out of an 86 Bronco, Engine is out of an '87 F150, with Mustang E7 heads, edelcrap intake and 600 cfm carb.

Anyone have input on this?

[cgrey8]

You have a lot of conflicting stuff here. First off you have a TFS Stage 1 in a truck. Then you are wanting to get fuel economy. Then you are being told you need a 3200 stall because its a truck.

I tend to agree that with a TFS Stage 1, you will want a higher stall...I don't know that you want to go quite to 3200, but yeah, a higher stall would be desirable with that cam so the engine is allowed to spin up to its torque band before the transmission starts loading it up. The problem is this is contrary to good fuel economy.

There's also the question of what you'll be doing with the truck. Is it just transportation and light duty stuff or will it be used as a truck, hauling significant loads and pulling trailers? If it's going to get loaded up on any frequency, a smaller cam or higher stall converter, or both is in order.

The good news is just going to an AOD will improve fuel economy over the C4 even if you don't change those other things. But being I've never driven an E303 or TFS Stage 1 equipped engine, I don't know just how lacking they are with torque off-idle. So I don't have any kind of feel for just how much lack in takeoff you are looking at by keeping the stock torque converter. And what I don't know is if you install a higher stall with the AOD, will that completely cancel out the fuel economy benefits of going to an AOD?

Ultimately, a fuel economical setup will try to keep the RPMs as low as possible and shift the transmission as soon as possible. And to help with that, you'd also need a cam that can produce torque off-idle to support/tolerate low RPM shifts. And that's not a TFS Stage 1 in a 302. In a 347 stroker or 351w, you might could get away with that. So if you are serious about getting good fuel economy from a 302 Ranger that's to be a daily driver, seriously consider swapping the cam along with the trans and keep the stock converter or buy a stronger aftermarket converter with the same K stall as the stock. And depending on just how much fuel economy you are wanting, you may even reconsider the rearend ratio if its a 3.73. For reference, I have a stock Explorer 302, 3.27 rearend, a T5 with 2.95 1st gear and .63 5th. When I drive, I'm mindful to shift as soon as possible to keep the RPMs as low as possible for the road conditions. The lower the RPMs, the better the fuel economy...unless the engine is lugging. On the Interstate, I travel 74 MPH@2000RPMs and get low 20s for fuel economy even with E10 gasoline. If I keep my speed in the 55-65MPH range, I have datalogged as high as 25MPG, but I've never actually calculated fuel economy that high at the pump so if I was getting that, it was being held back by whatever other driving was being done on that same tank. Even in mild stop-n-go city driving to and from work, I can eek out over 22 MPG (confirmed at the pump) when I'm driving to get good fuel economy. Now when the stop-n-go gets nasty or I get my foot into it, or I'm just driving it more aggressively, that quickly drops into the teens. The two biggest factors in helping me to improve the fuel economy have been the ability to tweak the tune to get the engine to run leaner than the stock tune commands and the ability to maintain the EGR. Believe it or not, a computer controlled EGR on a low compression engine isn't just an emissions thing, it's a fuel economy improvement. It's not heavily noticeable on gasoline, maybe a tad shy of 1MPG, but when I experimented with E85, running with and without EGR got me around 2MPG improvement. It was immediate and noticeable. If you are carbed, then you don't have the option to run EGR. But it is worth noting that I believe the majority of EGR improvements come from me running a stock engine that has a VERY low Dynamic Compression Ratio. Allowing more mass into the combustion chamber is a way to effectively increase the compression ratio and thus get a little more from the fuel you are putting in the engine. That's my theory anyway...

[plowboy34]

We run a stock converter on the boys truck with about the same engine package you have. Only difference is we run the "GTP" heads. A stall converter is going to hurt your fuel mileage. As cgrey8 stated alot depends on what you are going to do with the truck. We use the boys as a daily driver and frequent toy to play. We pull 20mpg on a regular basis and interstate running we pull 25 all proven at the pump. You say your gonna daily drive yours, if it's gonna be a average daily driver I would put a stock converter in it. Now since it is a 4WD you may be gonna play hard with it. Again as cgrey8 said alot depends on your use.

[cgrey8]

Yeah, the stock Explorer cam is purely an emissions cam. It's not even a fuel economy cam. Replacing it with anything is an upgrade for both performance and fuel economy. While I'm not a fan of the E303, it's still better than the POS stick Ford stuck in these Explorer engines.

I'm really curious to find out if that Crane Powermax 2020 (mild, high lift truck cam) in a 331 with GT40p heads and fairly high compression will improve my fuel economy or if I'll still take a hit from the deeper stroke. We'll see. I'd LOVE to be able to brag that I've got a 331 stroker that gets me 25+MPG. My wife's little Scion tC only gets 28-29 MPG and that's a little bitty car. If I could get 25-26 and have ~300hp on tap, I'd have the best of both worlds.

[Black84]

I should have stated what my use was in the first post. My bad. Truck will be used as a daily driver, with the occasional little penis contest from a stop light. moderate-frequent highway useage (65-70+ mph). I pretty much kept the truck because it has 4wd. Would love to have working 4x4 in some of the snow storms we get around here.

Would the truck "falling on its face" be due to it having a manual valvebody? I only assume that it has a manual valve body because no matter what adjustment I made, on the kickdown cable, or to the actuator on the transmission, it wouldnt downshift.

The Actual problem Im experiencing is, while coasting to a red stoplight that turns green before I come to a full stop, I press the accelerator, theres no downshift and there is about a 2 second hesitation before the truck takes off again. The engine will rev up before it takes off as well, Almost like the Converter is "spooling" up.

I know almost nothing about automatic transmissions, torque converters, and their functionings together, this is the first one Ive owned, Ive driven 5-speeds almost my whole life. I'm pulling the T-5 from my mustang to put in a Tremec, and I wanted to use the T5 in the ranger and wanted to mate it to my Dana 20 t-case, nobody makes that adapter anymore, I also heard the T5 didnt hold up very well in 4x4 applications.

You said to swap the cam as well as the tranny, what cam do you recommend? Go back to stock?

Thanks to all for the help!!

[Dave]

I really don't know what happened to our manners but Welcome! Don't know much about auto's either but -jump in guys - moire like thevacumne modulator? I ran a bone stock 302 but with a alum manifold and a 450 cfm Holley and never did have the kick-down attached. It would only down shift when I was up a certain rpm but ran great, even from a stop. Does it start out in what feels like first and then you feel it shifting thru the gears alright? Sure there are enough brains not being used right now that someone will have an answer. I know it's not required but we always like to have at least a general idea of where you are. Been really surprised at some sites that the guy I've been talking to is within 30 miles.
Dave

[Black84]

I really don't know what happened to our manners but Welcome! Don't know much about auto's either but -jump in guys - moire like thevacumne modulator? I ran a bone stock 302 but with a alum manifold and a 450 cfm Holley and never did have the kick-down attached. It would only down shift when I was up a certain rpm but ran great, even from a stop. Does it start out in what feels like first and then you feel it shifting thru the gears alright? Sure there are enough brains not being used right now that someone will have an answer. I know it's not required but we always like to have at least a general idea of where you are. Been really surprised at some sites that the guy I've been talking to is within 30 miles.
Dave

Dave,

Yeah the vacuum modulator is what I was talking about when I said the actuator on the tranny. THANKS FOR THE WELCOME. It does start in 1st, although it does not stay in first for very long, it also feels like it goes thru all the gears, it just doesnt down shift when I feel it normally should, like in my scenario I explained earlier. On that note Im hailing from Minneapolis.

[cgrey8]

Since you are already running a TFS Stage 1, you obviously have all the supporting hardware for fairly high lift (i.e. strong springs, roller rockers, etc). If that's the case, then I would say use a Crane Powermax 2020 like me. It's an excellent truck-oriented street cam or for any small CID daily driver. Although I'm not sure if Crane is back making that cam or not. The Comp-version of it is an XE258HR-12 although it lifts a little further than the Crane. Even if your springs work now, they might bind with that cam but worth checking into.

If you still want some sentiments of high performance WOT, then there are other Comp cams that will also work, but won't be quite as torquey off-idle. The XE264HR-12/14 comes to mind. If lift is going to be an issue, then Randy Mailik of RM Comp Racing makes custom cams. His HR256/263 is a VERY close match with the Crane 2020 when it is advanced 4-6° using an adjustable timing set. He also has a slightly more aggressive version, the HR264/265. I believe it will also need advancing. They have a built-in retard on them so they can work as drop-in upgrades on Speed Density F150s. For more info on those cams, visit the RM Competition website. The nice thing about these cams is they don't lift the valves as far so you can be assured you won't have bind issues if you are currently using the TFS Stage 1.

As for your trans issues, I have no clue. I'm not an automatic guy either.

[plowboy34]

If your engine is reving up before trans re-engages you are losing fluid pressure. I know you have checked the level and made sure all measurements are correct but believe me these have all been problems in the past. Your pump could also be going bad and when you let off gas it just doesn't have enough pressure to keep trans in gear. Even if it had a manual valve body it should still be in gear when you get back in gas , engine might lug out but it should not rev up before grabbing. Another problem about not downshifting could be the kickdown linkage on the inside of the trans could be broken or have been removed by a previous person. I seriously doubt you have a manual valve body cause you say it seems to shift fine from a stop. All manual valve bodies I know of you have to make every shift, up or down. To check to see if the kickdown rod is operating inside the trans would be to tie it all the way back just like as if you had the throttle wide open, put trans in Drive and take off slowly building speed. Engine should get to a higher RPM before shifting. If trans still shifts real fast then I would say that is where your problem lies.