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Please disregard my ignorance as I am not mechanically familiar with the truck, would something like this 2.56 ring & pinion gear set do it or there is more to it?Yes, putting a turbo 6.5 with 4speed in a A0-A1 truck would have the highest top speed.
Or just swapping the A0-A1 diffs into a turbo truck, same difference, gearing wise.
Most turbo trucks have a different gear ratio to accommodate armored acceleration, that’s by in part why the 1123 6.5 NA 4 speed trucks are very fast on top end. I had mine up to 90 as well doing some wide open testing last winter and decided it felt like i was coming back into the atmosphere and backed way offAha! So you engaged the Gravity Boosters aka downhill...I have the same transmission with 6.5L TD and maxed out at the 80mph on the speedometer, but didn't check with the GPS.
The transmission shifts smoothly and after it goes into overdrive, it's all high RPMs from there.
I will do another test using the GPS too after I finish all the engine fixes and report back.
I saw a chip and ECU mod by Heath Diesel, has anyone tried it?
1996-2000 Max E Tork Programming
You'll find brand name diesel performance parts at Dieselsite. Get advice for your truck from the owners who are also certified AMSOIL distributors.www.dieselsite.com
Got it! Yes, Hammer laid out the ratios clearly. Are these differentials like in civilian trucks where it can be configured with different ratios by just changing a few parts like the pinion & ring and keep everything else the same?Most turbo trucks have a different gear ratio to accommodate armored acceleration, that’s by in part why the 1123 6.5 NA 4 speed trucks are very fast on top end. I had mine up to 90 as well doing some wide open testing last winter and decided it felt like i was coming back into the atmosphere and backed way off
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I always Thought it was just an AMC model 20 diff. I’m sure someone here can confirm that. I was looking at Detroit lockers and I think it was the sameGot it! Yes, Hammer laid out the ratios clearly. Are these differentials like in civilian trucks where it can be configured with different ratios by just changing a few parts like the pinion & ring and keep everything else the same?
Here it is and if that's the case, can we just pop in/ swap the two gear parts and keep the same bearings and all other parts the same?I always Thought it was just an AMC model 20 diff. I’m sure someone here can confirm that. I was looking at Detroit lockers and I think it was the same
What about a ratio for overdrive? I feel 4 shifts, so 1, 2, 3, 4, od.He could have, but I doubt it.
And to put all the numbers for gearing.
For the differentials themselves.
A0-A1 have 2:56
A2’s have 2:73 (4 spd, 65. NA)
ECV on up, 3:08 (4 spd, 65. Turbo)
Geared Portal hubs are 1.92:1
Transmissions
3rd gear is 1:1,
4th gear is .75:1
Final drive "axle" ratios
A0-A1 = 4.92
A2 = 5.24
ECV + = 5.91
Final driver in TOP gear
A0-A1 = 4.92 3rd gear
A2 = 3.93
ECV + = 4.44
Easy to see the A2 has the best gearing for top speed
They are only 4 speeds, you are feeling the torque converter locking up to make it feel like another gear.What about a ratio for overdrive? I feel 4 shifts, so 1, 2, 3, 4, od.
Yes, Dana 20 differentials, just like in the Jeeps.Here it is and if that's the case, can we just pop in/ swap the two gear parts and keep the same bearings and all other parts the same?
Between front and back would be $600 + time, a great upgrade IMO?
Dana 20 and AMC 20 are not the same. I think the AMC model 20 has an 8 3/4” inch ring gear. Dana 20 is a transfer case. I know Dana 30 is a front diff but I don’t think I have heard of a 20Yes, Dana 20 differentials, just like in the Jeeps.
And yes, doing a ring and pinion swap, properly setup, is the way to change to a number of different gears.
Thing is, getting the low numeric gear ratios are not common. Most offerings are 3.54 or up.
Easiest answer is to swap the differential itself out. Cheaper as well.
The diagram should be for an AMC20 (or I thought it was), which is used in the H1 they say.Yes, Dana 20 differentials, just like in the Jeeps.
And yes, doing a ring and pinion swap, properly setup, is the way to change to a number of different gears.
Thing is, getting the low numeric gear ratios are not common. Most offerings are 3.54 or up.
Easiest answer is to swap the differential itself out. Cheaper as well.
It's hard to find any gearing higher than the 3.54 because of the portal hubs aren't very common. They almost double the gear ratio, so you have to start out a lot higher.The diagram should be for an AMC20 (or I thought it was), which is used in the H1 they say.
A brand new one is listed for $4k vs. $1.5k -2k re-manufactured vs. <$300 for just the ring & pinion?
But you are saying going lower is not common practice?
Maybe because the thinking is that trading torque for hp is not a good idea? (in electrical engineering it is trading Amps for Volts or vice-versa, where the power Watts stays the same). In my ECV A1 case, the 6.5TD already has more torque and I don't have any heavy armor, therefore I think it would be an OK trade that the engine can handle? What are the ratios in the H1s with the 6.5TD?
The info we got is that the A0-A1 is the fastest and has a 2:56 ratio.It's hard to find any gearing higher than the 3.54 because of the portal hubs aren't very common. They almost double the gear ratio, so you have to start out a lot higher.
And as the HMMWV is a relatively uncommon application in the real world, there just isn't much out there.
Trading low end torque for top end speed is fine, but within reason. theoretical book top speed with the 2.53 gears would be around 86mph, which also happens to be the max speed rating for the military tires a lot of us run. If 95% of your driving is cruising the highway, then you should be fine.
On the other hand, if you like to off road a lot, then the lower end torque is a lot more useful than top end.
It all depends on what you want to do with it.
Do you mean on 16.5s?I think that turbo truck with 42’s would be just fine
16.5 24 bolt even spacedDo you mean on 16.5s?
Or on 17s?
Which brings us back full circle to the thread topic lol.
Fastest for gear ratios, yes. But needs the overdrive transmission to take advantage of that gearing.The info we got is that the A0-A1 is the fastest and has a 2:56 ratio.
Changing the tires from 37” to 42” would increase the speed from 70mph to about 79.5mph, or about 13%. Given the amount of lifting and modifications required to fit the larger tire, it represents a relatively marginal improvement.Fastest for gear ratios, yes. But needs the overdrive transmission to take advantage of that gearing.
BTW, for cost, I meant to just get take out differentials, ie,. surplus.
But if you have an ECV up truck, then your diffs/brakes are better.
Finding 2.56 ring and pinion sets will not be easy.
And don't forget the brick wall affect of driving these at speeds over 60 mph. Increasing speed really increases the wind drag.
I know if I cruise at 80 mph, and a headwind comes up, it slows me slow down. Usually not under about 70 mph though.
MaxJeep1 statement is that getting taller tires has the same basic affect of changing your gear ratios for higher stop speed. Of course other things need to happen to fit tires of that size, but still easily doable.