Compatible transmissions for the M35a3 with the cat 3116

[73m819]

Just a simple question, what is the SPEED RATING on those tires

ALSO why in HE!! would someone do "So 68.5mph x 1.15 = 78.8mph " in a old army truck other then to try to screw the MV hobby

 

[135gmc]

One thing to remember if you want to cruise at anything over about 45 MPH is that the military usually doesn't balance tires, and higher speeds can become real exciting if the tires are out of balance. I took my front tires in for balancing, and they came back with about a pound of weight on each tire. It totally changed the way the truck drove -- I didn't have to hang onto the steering wheel - instead, I just steered the truck normally.

 

[Rambling Wreck]

Just a simple question, what is the SPEED RATING on those tires

ALSO why in HE!! would someone do "So 68.5mph x 1.15 = 78.8mph " in a old army truck other then to try to screw the MV hobby

I haven't bought the tires yet so I don't know the speed rating. It is something I will carefully consider when deciding on tires though. I didn't say I was going to travel at 78.8 mph. That is simply the mathematically calculated top speed. Please explain to me how the heck I am screwing over the MV hobby? I think that is a wild and unwarranted accusation.

 

[Rambling Wreck]

sometimes other methods work, sometimes they give false info. the simple math formula for this is :
mph = ( rpm * radius) / ( 168 * ratio)
using loaded radius is more accurate, ratio is final drive ratio including trans, rears, etc.

tom

Tom,

Using your equation I get the same numbers as when doing it my way. I think your original calculations were off because you were using the wrong rpm.

So... To answer your original question that started this mini thread: Yes I do think it is worth it ($2,400 for 2 Ouverson gears) to get a 37% boost in top speed. That top speed would then further be increased by about 15% when I install larger tires. The tires would be an additional cost but I wanted bigger tires anyway.

 

[trukhead]

Yeah, BUT, I am not turning 2,200 rpm. The cat will do 2,700 all day every day.

So... according to your math, if you apply the right rpm:

(56 / 2200) x 2700 = 68.73 mph which is basically the 68.5 that I have shown above.

You really need not even apply pi to figure this out. Given that I know what speed I can travel at what rpm (50 mph @ 2,700 ish), I only need to know the different gear ratios and tire sizes to determine the speed. The pi's and everything else cancel out of the equations.

Now you can use a formula plug in whatever variables you want like tire size, rpms gear ratios.

"Give a man a fish, feed him for a day, teach a man to fish, feed him for life" (paraphrasing)opcorn:

 

[Rambling Wreck]

Now you can use a formula plug in whatever variables you want like tire size, rpms gear ratios.

"Give a man a fish, feed him for a day, teach a man to fish, feed him for life" (paraphrasing)opcorn:

I didn't need the formula. Someone questioned my calculations so I was wanting to be shown where they were wrong. Turns out, my calculations weren't wrong, the other person was using an incorrect parameter in their calculations.

But now the formula is there for all those needing to be taught how to fish.

 

[jaymcb]

I guess my question of 'is $3600+Labor worth it to increase top speed?' question has to be tempered with 'will the 3116 move an M109 that fast if I already have 395's?'

 

[Rambling Wreck]

I guess my question of 'is $3600+Labor worth it to increase top speed?' question has to be tempered with 'will the 3116 move an M109 that fast if I already have 395's?'

Here's a fish:

If you already have 395's and are running the Cat 3116 and Allison 1545, then your existing top speed should be around 56mph @ 2,700 rpm. If you were to switch from the 6.71 gears to the 4.90, you could realize another 37% speed increase. So, yeah, theoretically you could run 77ish mph. Also, this means that you could run 63mph while only turning 2,200 rpm. This point is lost on the people who freak out on this site every time top speed is mentioned.

There should be some ways to squeeze more horsepower out of the 3116 if you are concerned about the decreased acceleration that could result from the modifications.

 

[1 Patriot-of-many]

Here's a fish:

If you already have 395's and are running the Cat 3116 and Allison 1545, then your existing top speed should be around 56mph @ 2,700 rpm. If you were to switch from the 6.71 gears to the 4.90, you could realize another 37% speed increase. So, yeah, theoretically you could run 77ish mph. Also, this means that you could run 63mph while only turning 2,200 rpm. This point is lost on the people who freak out on this site every time top speed is mentioned.

There should be some ways to squeeze more horsepower out of the 3116 if you are concerned about the decreased acceleration that could result from the modifications.

Not everyone is freaking out, I too am looking at options to get lower rpm at 50-55 MPH. What would be the rpm's with the standard tires at 50 and 55 mph with the gear change?

 

[Rambling Wreck]

Not everyone is freaking out, I too am looking at options to get lower rpm at 50-55 MPH. What would be the rpm's with the standard tires at 50 and 55 mph with the gear change?

If your tires are 42" tall, the 4.90 gear should give you:
1,960 rpm @ 50 mph
2,156 rpm @ 55 mph

 

[Rambling Wreck]

Now you can use a formula plug in whatever variables you want like tire size, rpms gear ratios.

"Give a man a fish, feed him for a day, teach a man to fish, feed him for life" (paraphrasing)opcorn:

LOL

 

[akparker0369]

BAHAHAHA, Ron Swanson, you hillarious b*stard

Keep us posted, I was looking at the 4.90's the other day and wondering how badly they would impact accelleration. I'll be interested to see how it turns out if you do the swap.

I wonder how much the impact would be multiplied with the multi- fuel where you can't get as much HP out of the motor.

There has to be at least one guy on here that has done this swap already.?.?

 

[jaymcb]

Here's a fish:

If you already have 395's and are running the Cat 3116 and Allison 1545, then your existing top speed should be around 56mph @ 2,700 rpm. If you were to switch from the 6.71 gears to the 4.90, you could realize another 37% speed increase. So, yeah, theoretically you could run 77ish mph. Also, this means that you could run 63mph while only turning 2,200 rpm. This point is lost on the people who freak out on this site every time top speed is mentioned.

There should be some ways to squeeze more horsepower out of the 3116 if you are concerned about the decreased acceleration that could result from the modifications.

Well, there's NO way I'd ever run more than 65 in my m109...but it would sure be nice not to run up against 2700 whenever I'm on a highway. Just need the justify on the 3600...well, 4200, because I want to do manual lockers on the front axle too.

 

[73m819]

One more thought on the 4.90s,, by using them you will be putting one he11 of extra load on the clutch

 

[jaymcb]

All of the 3116-powered A3's have Allison 1545 auto's...or did I miss something?

 

[Rambling Wreck]

All of the 3116-powered A3's have Allison 1545 auto's...or did I miss something?

To my knowledge that is correct.

 

[m-35tom]

so if that is the case, all a3's have lockup converters . in the past there has been info that was probably a guess, not based on real intel.

 

[duramaxdiesel1]

manual locking hubs definately made a difference in the way it drives and steers. just dont take it on the highway much. more back roads and car shows. its made to be enjoyed.

 

[trukhead]

so if that is the case, all a3's have lockup converters . in the past there has been info that was probably a guess, not based on real intel.

This is from the allisontransmission.com site:

Chart sez 5602 AT 1545 were make for the M35 2 - 1/2 ton ESP

Some one stated 6000 M35A3's were produced so did they put 400 non lockups in or did they produc less than 6000 M35A3's

Allison Transmission

LOL

WHooaaa, I reeled in a big one

 

[duramaxdiesel1]

yes there was only 5600 of these trucks produced between 1993 and 1999. in my manual i have for this truck it doesnt mention any lock up torque convertor. this is what the manual says it has the allison at-1545p constant mesh tranny. 1st gear 3.45 to 1, 2nd gear 2.25 to 1, 3rd gear 1.41 to 1, 4th gear 1.10 to 1, reverse 5.02 to 1. the weird part is that they used 15w-40 diesel oil in the transmissions. you would of thought tranny fluid would of been used. my truck does 55mph foot to the floor up and down hills now. all i did was installed locking hubs on the front end to make the front tires turn freely.