How Much Power is Too Much for Running Gear?

[Blown]

I am sure some of you V8 guys have built-up some good power numbers as well as Turbo and Blown rigs. I hope this will help answer questions for builders. I have been researching to see if my rig would hold-up to 10lbs of boost with a rebuild, heads, cam and headers..............265hp/300ftlbs.

I am curious of what kind of power is being run through what? Please, anyone who is running more than average post-up your running gear and any problems you have had. Here is a format to cut-n-paste and I will go first.

Engine/Power:........................ Blown 4.0SOHC/207hp/250ftlbs too ground
Transmission(clutch)/T-case:.... 5R55E/Dana28
Front axle/Rear Axle:.............. Stock/"X" 8.8
Tire size/Gearing:................... 255/70-16/3.73
Driveshaft mods:................... Custom for t-case swap, no stronger than stock

No problems to date with only 6lbs of boost.

 

[85_Ranger4x4]

Knowing nothing of your t-case or how much boost a stock 4.0 can happily take (10psi is quite a bit) I am going to say your trans is probably the weak link.

But Ford threw a 300hp 4.6 at that trans in the big heavy Explorer (and Mustang), you might see what the differences are between the 02+ Explorer and Ranger versions.

 

[adsm08]

In your setup the Dana 28 AWD unit is the weak link. Ford's automatic transmission names are fun, because the give you information. The 5R55 transmission for example

5- First digit is the number of gears, so a 5-speed auto.
R- Orientation type, so this is a rear wheel drive trans (F would indicate front wheel drive)
55- the 3rd and 4th positions indicate the power the trans is rated for. This transmission is rated to handle up to 550 ft/lb.


The position in these gives some other info that is less important. IIRC E is electronic controls, W is wide range (gear ratios farther apart) and I don't really know what S would stand for aside from "sucks".

 

[Shran]

I agree, the transmission being the single item connected to the engine is probably the most likely point of failure.

But really it depends on what you're doing with the truck... parts failure in a daily driver is going to happen because stuff simply wears out rather than offroad or race applications where things break because they're poorly designed, too small/weak, or abused.

 

[Blown]

Thanks for the input!

I cannot find any info for what the Dana 28 T-Case is rated at. I have the stock case and driveshafts just in case I need them.

I wouldn't go to 10lbs of boost without a built short block, better heads, intercooler, cam, larger MAF, and larger volume fuel pump. From my research, I believe it would hold-up to 14lbs max but do not want to push it that hard.

 

[tinman_72]

...55- the 3rd and 4th positions indicate the power the trans is rated for. This transmission is rated to handle up to 550 ft/lb...

I am pretty sure that the 3rd and 4th digits represent newton meters.

 

[Blown]

It's Foot Pounds.

550ftlbs is more than I thought and I would really be pushing the 5R55E to it's max.

The stock torque converter should be able to almost double the torque from the engine, 1.85 X 300 = 555ftlbs (TC X SOHC torque @ 10lbs of boost)

As always cost really go up steeply in this game. I would need a tranny controller and stronger tranny and then what would break next? Poop, I can't see putting anymore into my old Ranger and need to start looking for another toy.

 

[85_Ranger4x4]

It is kind of a fuzzy number, not sure if that is at what torque level the thing just flat out breaks if the wheels are not allowed to spin or what.

It is not what they are rated to operate at, otherwise the 4R70W would have been much more common (more than as dirt common as they already are) and there would have been little use for the 4R100.

 

[adsm08]

It is kind of a fuzzy number, not sure if that is at what torque level the thing just flat out breaks if the wheels are not allowed to spin or what.

It is not what they are rated to operate at, otherwise the 4R70W would have been much more common (more than as dirt common as they already are) and there would have been little use for the 4R100.

Or any of the TorqShift transmissions for that matter.

I am not, by any means, an expert on automatics. I have what I would consider an above average understanding of their operating principles, but almost no ability to diagnose or repair them. My areas of specialty were electrical/electronics, driveability, and steering, suspension and alignment.

But, I believe that 550 number is the point where the clutches can no longer hold if the wheels are not allowed to spin. Given the way power flows through an automatic it is very likely that if you would load the truck down, or hitch it to a trailer that required 600+ ft/lb to get rolling and had an engine that was able to produce that power (including the torque converter's multiplication factor) that the clutches would first begin to slip, and then just fry themselves, long before any hard parts were damaged by anything but heat.

 

[Blown]

This is what I needed to know. If I went with 12lbs of boost I would overpower the tranny.

I do see tranny rebuild kits with improved clutch plates to hold a bit better................

 

[85_Ranger4x4]

Or any of the TorqShift transmissions for that matter.

I am not, by any means, an expert on automatics. I have what I would consider an above average understanding of their operating principles, but almost no ability to diagnose or repair them. My areas of specialty were electrical/electronics, driveability, and steering, suspension and alignment.

But, I believe that 550 number is the point where the clutches can no longer hold if the wheels are not allowed to spin. Given the way power flows through an automatic it is very likely that if you would load the truck down, or hitch it to a trailer that required 600+ ft/lb to get rolling and had an engine that was able to produce that power (including the torque converter's multiplication factor) that the clutches would first begin to slip, and then just fry themselves, long before any hard parts were damaged by anything but heat.

I am no expert either, I have heard the same thing about how they are rated. And the rating is probably on a new trans with new fluid too. Then I look at what they hang on the front of the trans vs what the rating is and think "they have a pretty big cushion there"

 

[don4331]

Couple things:

Stock Ford TC is "stalled" at ~1,600rpm; so by time the engine is making torque peak, it isn't providing any torque multiplication.

If you look at the NP transfer case chart, they are using a "load factor" of 2.2. Justification - even with flywheel/flex plate & torque converter, peak torque is higher than average torque and it is average torque which dyno measure. And if the drive train part can't handle the peak, in case of transmission, clutches slip, and once they start slipping, it is downhill.

So, Blown's engine need not exceed 550 ft-lbs, but merely 250 before stock 5e55 becomes suspect. However, that needs tires to have sufficient traction to put that load on tires - tough with Ranger; easier with loaded Explorer towing trailer.

Some other numbers:
Spicer 1310 u-joints have a continuous rating of 400 ft.lbs./max continuous of 800 and yield of 1600. 1350 u-joints would increase numbers to 680/1240/2260. 1330's numbers aren't much better than 1310 - 890 max cont and 1850 yield - I can't find a reliable continuous number.

From January 2004 Four Wheeler p. 60; Dana 35 has max continuous of 870 ft.lbs. output and 2,500 maximum; Ford 8.8 28 spline 1,250/4,600 while 31 spline 1,460/5,100.

With Dana 28, Blown doesn't have low range, so, u-joints/axles aren't in real danger unless shock loaded (e.g. spinning on ice, then hitting concrete)

I don't have any numbers for the front CV joints or the Dana 28 but it is probably in same class as NV14x series. Dana 28's challenge will be - clutches can't hold load when worn, so one tire will unload.

My combo:

Engine/Power:........................ 331, 9.6:1 CR, AL heads
Transmission(clutch)/T-case:.... 4R70W/NP242
Front axle/Rear Axle:.............. Stock/"X" 8.8
Tire size/Gearing:................... 255/75-17/4.10
Driveshaft mods:................... Custom for s/c l/b swap, Superlift CV in front, no stronger than stock

My concern is when I drop the NP242 into 4 low lock, I can put entire power to the Dana 35. So far I have been careful with skinny pedal...

On my '68 F-100, it was 1st older u-joint in front driveshaft that failed (and took driveshaft and front output on Dana 20 with it in during immediate following pole vault), once repaired, outer axle shaft in the front Dana 44 was next to fail. That got expensive enough for a 17 year old to start practicing caution on throttle.

 

[85_Ranger4x4]

So, Blown's engine need not exceed 550 ft-lbs, but merely 250 before stock 5e55 becomes suspect. However, that needs tires to have sufficient traction to put that load on tires - tough with Ranger; easier with loaded Explorer towing trailer.

SOHC 4.0 is rated 254 out of the box...

 

[Blown]

Don thanks for your post! Numbers is good including the torque ratings you posted. I knew those numbers in the past after I managed to blow up a stock ford 9", a couple of Dana 44 u-joints and then in a built 9" I blew-up the ARB! I went with one ton gear including 1350 driveshafts and 40's after that with no further issues. This in a Bronco with blown 393, stupid me tried nursing running gear with that much power, a doubler and actually kept it together most of the time.

My T-case concern is eased a bit by the fact that the lightest case in that spec sheet if rated for 1,590ftlbs! I too am concerned for the front axle, but with the Dana 28 the front only get's 33.3% of the torque and I will only use the clutch for very slippery slow conditions. I have also found better friction plates/clutches for the 5R55e and I can tune to raise the line pressure for firmer engagements to save the tranny. If I rebuild the tranny, I might as well go with a better torque converter too.

The biggest question now is do I want to put $3,500 to $4,000 in my truck to do this when I am seeing much better newer engines, transmissions, and mileage in newer vehicles.

Couple things:

My combo:

Engine/Power:........................ 331, 9.6:1 CR, AL heads
Transmission(clutch)/T-case:.... 4R70W/NP242
Front axle/Rear Axle:.............. Stock/"X" 8.8
Tire size/Gearing:................... 255/75-17/4.10
Driveshaft mods:................... Custom for s/c l/b swap, Superlift CV in front, no stronger than stock

 

[Blown]

After sleeping on this, I am going to proceed slowly. I can build this over time. First priority is the intercooler. I should be able to go to 8lbs with an intercooler, head studs, and better head gaskets.

My current build makes about 65ftlbs at 2,000rpm and 160ftlbs at 3,000rpm at the crank. Multiply those by 2 or double and you can see that the results of 130ftlbs and 320ftlbs is still well below the trans rating of 550ftlbs. after it couples and locks the Torque Converter.

I am very interested in others power builds, running gear, and any troubles with it as Don and I posted?????