A Different Question About 4.10's

[Ross]

I've been thinking more about 4.10's lately. The people who have them seem to agree that the 300 or so extra RPM's at 70 MPH don't make any noticeable difference in the ride, so that's good. My question is about engine life.
I have heard people whose opinions I respect say that it's not MILES that wear out an engine, it's RPM's. Any given mileage with mostly city driving will result in a certain amount of RPM's, but that same mileage with a lot of highway driving will result in a lot more RPM's, therefore more engine wear and tear. Seems to make sense to me.
Since I do a fair amount of highway driving, it seems like those extra RPM's from the 4.10's would increase the engine wear, and shorten my engine's life somewhat. True or false?
Maybe this is really a non issue, but it seems worthwhile to ask and to get some collective wisdom on the subject, since I would like to keep this car for awhile.

[PAPAJOHN]

Just my $.02 worth of math --- the 4.10 is about 1.15 times the RPMs of the stock , so wouldn't that mean that when you get 100,000 miles on the car, it would be the engine wear of 115,000 miles if you had the 4.10 ( compared to the stock)

[Ross]

That's one way to look at it, assuming that there is a linear addition to the wear and tear, as opposed to a geometric addition. ( I'm trying to sound smart.) I don't know which really applies, if either, so I'm asking. Thanks for the input.

[cyclone03]

IMHA:
Ok how about this,
The gear helps the car move from a stop, in normal driving you use less throttle.The engine see's less load for the same amount of work.Remember the engine torque passes threw a transmission and the rear end all increasing torque multiplication.

So yes you run a higher RPM,but the engine is being loaded less.
In the real world,stop and go,my GUESS is the idleing in traffic does more damage.

[Fourth Horseman]

As long as you're changing your oil and filter regularly and you don't romp on it until the engine is warmed up, then I don't think you're going to see any reduction in engine life with 4.10s over stock 3.55s. Just my 2 cents.

[RF Overlord]

I have heard people whose opinions I respect say that it's not MILES that wear out an engine, it's RPM's.

Well, that's sort of true...it's not miles or even RPM, it's actually piston travel that counts. For every mile you drive, and for every minute the motor is running, the pistons travel up and down in the cylinders "X" feet. So, as PAPAJOHN said, if you travel 100,000 miles, the pistons have travelled up and down 15% more times with 4.10s than with 3.55s, so your equivalent wear would be "115,000 miles worth". As Garfield (the cat, not BigDog's alter-ego) likes to say: "Big Fat Hairy Deal"...

Steve Babcock :bows: told me at Indy that they originally wanted to put 3.73s or 4.10s in the car from the factory, but that was nixed for "gas-guzzler" reasons.

[BillyGman]

I agree w/Fourth Horseman on this one. If any of this reduced engine life theory was true, than that would mean that al the cars several years ago which didn't yet have transmissions w/an Overdrive gear wouldn't have lasted as long since they were all reving higher on the highway due to a top gear of 1:1.... the O/D makes all the difference, and keeps the revs low enough even w/the 4.10 gear ratio.

[Smokie]

I've been thinking more about 4.10's lately. The people who have them seem to agree that the 300 or so extra RPM's at 70 MPH don't make any noticeable difference in the ride, so that's good. My question is about engine life.
the 4.10's would increase the engine wear, and shorten my engine's life somewhat. True or false? That extra 300 rpms at 70 mph happen every minute, taller gears: more up and down=more wear and tear.

I noticed you done some work to your car...far more than me and I am very happy with takeoff, the gears will improve your launch and they will also cause more wear and tear...you just need to decide what matters more; a stronger launch or some extra miles at the end of the clock.

It's physics, you can't have one without the other...life is short, do what makes you happy.:)

[mrjones]

Well, that's sort of true...it's not miles or even RPM, it's actually piston travel that counts.

That's why buses and big trucks have HOURMETERS on the engines. And they don't actually measure hours, they measure total revolutions on the engine. It would actually measure hours if the engine ran ONLY at the designated speed on the hourmeter, but I digress.

I haven't yet changed the gears in my Marauder, but I did go from 3.08's to 3.73's in my Mustang. I lost about 2mpgs on the hwy, but it made a tremendous difference in the way it feels. Did I say tremendous difference?

[BillyGman]

I haven't yet changed the gears in my Marauder, but I did go from 3.08's to 3.73's in my Mustang. I lost about 2mpgs on the hwy, but it made a tremendous difference in the way it feels. Did I say tremendous difference?
Just remember that in a heavier car like the Marauder, it will not make as big of a difference unless you're pushing some very big HP #'s. Much bigger than a stock Marauder does. However I do think that 4.10 gears are the best all around gears for these cars. They're a perfect compromise between the street and the track. best of both worlds, master of none you might say. But hey, you can't have everything.

[Ross]

Good input, guys. Thanks for all the help. I need to do some thinking now and make a decision about this. I'm looking for a little better launch, and I'm defiitely staying NA, so I figure the gears are my next logical step.

[RF Overlord]

But hey, you can't have everything.

I dunno about that...BARRY has everything...13.5 in an N/A Marauder...(grumble-grumble...bastage...must be hidin' a NOS system under the back seat...grumble)...bastage...

[BillyGman]

I dunno about that...BARRY has everything...13.5 in an N/A Marauder...But if he had 4.56's then he would be running a better ET than he is now. And along w/that better ET he would be giving up some top-end on the highway (the top end over 120 MPH). That's what I meant. There are always trade-offs. You cannot have it all. 4.10 gears are a good compromise between the two.

[jstevens]

My $0.02

I went with the chip and 4.10's and you will not, did I say will notice a big difference. This makes the car a total beast.
I cruise on the highway at 74mph at 2500rpm's which I feel is pretty safe.

I like you am worried about engine life but want to enjoy the seat of the pants feel.

Do it, you won't regret it. By the way, I travel 64 miles a day freeway for my work commute.

[bugsys03]

Steve Babcock :bows: told me at Indy that they originally wanted to put 3.73s or 4.10s in the car from the factory, but that was nixed for "gas-guzzler" reasons.[/QUOTE]


I get the same MPG with the 4.10's as I did stock :2thumbs:

[Silver_04]

I wouldn't worry at all about the RPM increase. I look at it this way: some of us drive on 55mph interstates regularly, others drive on 75mph interstates regularly and our cars are all supposed to last roughly the same amount of time. When you make a gear swap and cruise on the highway, the engine just thinks the speed limit was raised a tick. :) Yes, the piston will be traveling more, but that's it's job IMO.

DON'T FEAR THE GEAR. I'm taking the plunge next month. Whoo hoo.

[hbarrett]

Ross,
I bought the 4.10 gears and tuner from Dennis Reinhart and had the gears installed two days ago, loaded the program last night. I wish I had done this the first month I owned the car (June 04). The difference is exactly what I felt the car was lacking, not too much, but definitely enough power and acceleration at the low speed and low RPM range. It's the way now that I felt it should have been built from the factory. Do it. I guarantee you will be pleased. Forget the wear and tear issue with this car. The powertrain design is plenty robust for a few extra RPMs. Good luck!
Howard
Good input, guys. Thanks for all the help. I need to do some thinking now and make a decision about this. I'm looking for a little better launch, and I'm defiitely staying NA, so I figure the gears are my next logical step.

[jobrien8]

This may help you in your decision. I work for Ford at the Dynamometer Laboratory doing engine testing. My main focus right now is engine durability. We have run these engines through various types of durability tests. The two that we use most frequently on all V-6, V-8 and V-10 are the Cologne and FIE. The FIE runs the engine at the rpm points of peak torque and horsepower, plus horsepower +5%. The peak torque runs for 5 hrs and 45 minutes; peak horsepower for 3 hrs. 45 minutes; peak horsepower +5% for 2 hrs.. There is also a 30 minute idle, and 2 high rpm light load points for 30 minutes. This test can run for 300 or 600 test hours. The Cologne test runs mostly between the peak torque and horsepower +5%, from part throttle to WOT. There are a couple of idle points. Two soak points, one for 3 minutes near the middle; and one for an hour at the end of each cycle.
Engine integrity checks are performed every 50 hours, which includes compression, cylinder leakdown and oil/filter change plus others.
Now these engines, with some exceptions, complete these tests. Considering the rpm and torque ranges these engines run, which you would not be able to, changing to a 4.10 axle would not be a problem for the engine. Plus considering all the supercharger mods that have been done without any bottom end failures, you won't have a problem.
Hope this helps with your decision.

[BillyGman]

WOW!! That's some serious hammering on those engines that you guys do!! I never knew that. Very interesting information. Thankyou. :bows:

[Smokie]

Now these engines, with some exceptions, complete these tests. Thank you for the info on the engine testing. What percentage of the engines tested don't complete the test ?

Do you have a break down of the specific engine's tested ?
Do our "engines" get tested ? How do they stack up vs. SOHC 4.6 L ?

Thank you for your fine post.

[gonzo50]

DON'T FEAR THE GEAR. I'm taking the plunge next month. Whoo hoo.
Same here Silver_04.....Team Ford in ATL is doing mine.

Ross, Do it. I guarantee you will be pleased. Forget the wear and tear issue with this car. The powertrain design is plenty robust for a few extra RPMs. Good luck!
Howard
I agree, with all the superchargers out there, these engines are doing just fine.....

This may help you in your decision. I work for Ford at the Dynamometer Laboratory doing engine testing. My main focus right now is engine durability. The peak torque runs for 5 hrs and 45 minutes; peak horsepower for 3 hrs. 45 minutes; peak horsepower +5% for 2 hrs.. There is also a 30 minute idle, and 2 high rpm light load points for 30 minutes. This test can run for 300 or 600 test hours. Engine integrity checks are performed every 50 hours, which includes compression, cylinder leakdown and oil/filter change plus others.
Now these engines, with some exceptions, complete these tests. Considering the rpm and torque ranges these engines run, changing to a 4.10 axle would not be a problem for the engine. Plus considering all the supercharger mods that have been done without any bottom end failures, you won't have a problem.
Hope this helps with your decision.
If they can handle that kind of torture, thats good enough for me. :director:

[Ross]

Very interesting stuff. I think I may be getting a little closer to saying YES.