4.10 & Under drive pulley

[Mike827]

Is 4.10 gears good for the mm? I have heard by switching 3.55 gears to 4.10 gears will give the mm better low end. And the top end will lower. Can somebody please explain to me about 4.10 for the mm. Also I have one more question. What does changing the under drive pulley does for the mm. What size is recommended? Thank you

[ImpalaSlayer]

Is 4.10 gears good for the mm? I have heard by switching 3.55 gears to 4.10 gears will give the mm better low end. And the top end will lower. Can somebody please explain to me about 4.10 for the mm. Also I have one more question. What does changing the under drive pulley does for the mm. What size is recommended? Thank you

yes 4.10s will "give the car more low end" and you WILL loose top speed but really who drives at 100+ on a daily basis? infact i dont even know if its been tested to see the difference in top speeds. anyway, it shouldnt be a concern to you. they are definitly wothrt it and make the car much more fun to drive. the under drive pullies only come in one size for the mm. i had them but didnt notice much difference if any. id buy a CAI if you dont have one already instead.

[LANDY]

in my car on third gear with 3.55's i topped out @ almost 140mph. with 4.10's 129mph hope i helped

[MrBluGruv]

you sure that was third? I was pretty sure 3rd usually stopped between 110 and 120 on 3.55 cars. if 3rd hit 140, then 4th could conceivably hit like 200 or more

[LANDY]

it was more somewhere between 135-140 with the 3.55's.
with the 4.10's it hit that 129 on the dyno @ Reinhart's place

[Stranger in the Black Sedan]

if 3rd hit 140, then 4th could conceivably hit like 200 or more

If you weren't pushing a house through the air

[cougar9150]

Best mod I did on my first MM was the 4.10s and a tune. Changed the way the car drove completely, made it feel 2000lbs lighter. Look into a driveshaft at the same time if you will be doing much high speed driving i.e. sustaining 100mph and above for more than a few seconds.

[ctrlraven]

you sure that was third? I was pretty sure 3rd usually stopped between 110 and 120 on 3.55 cars. if 3rd hit 140, then 4th could conceivably hit like 200 or more


If you weren't pushing a house through the air
Correct!

I've done 140 before and was in 3rd. Yes you will lose some top end but unless you plan on being past 120/130 mph A LOT then it doesn't matter, but 4.10 gears is a nice performance upgrade.

Same principle they talk about with the Veyron, it only takes 270hp for it to reach a speed of 155 mph but to get to 253 mph it needs another 730hp. The fastest you go the more mother nature tries to hold you back.

[DEFYANT]

the fastest you go the more mother nature tries to hold you back.

B!tch

............

[RacerX]

UD pulleys aren't worth it IMHO. You can get side effects too like having to upgrade to a HO alternator like I'm doing... :shake:

[MrBluGruv]

it was more somewhere between 135-140 with the 3.55's.
with the 4.10's it hit that 129 on the dyno @ Reinhart's place

Damn, something isn't quite right with my car then. :(

how much variance in speed do you think there would be in the speedo reading where that actual speed is 70 but say I had 4.10s instead of 3.55s? I could swear they are 3.55s but I don't ever remember getting that fast in third. :(

[Hotrauder]

On the track at Sebring in 3rd with the OD off and 4.10's in the rear at 6200rpm I was at "speedometer 133" every lap on the back straight. I thought about using OD as there was plenty of track left but was way to busy competing and trying to stay off the wall as I learned the track to figure out where would be a good place to engage it and not be looking for a bus ticket home.:D The differential from speedometer and GPS is one mph at 80, not sure at 133. Dennis

[MrBluGruv]

I don't think what I meant came out right. I meant like if I had 4.10 gears but the computer THOUGHT I had 3.55s.

Between asking that question and now though I had a "duh" moment and realized how easy the calculation is and did it. :-P The thing that bothers me though is I think my speedo is already 3 to 5 mph off as it is at around 70mph, reading faster than actual speed. I have 245/45/18 tires in the rear instead of the stock size, would that minute difference account for that many mph difference?

[SC Cheesehead]

I'm thinking that tuning adjustments have to be made in the shift schedule to account for the difference in 4:10's vs 3:55's, and that tire size (diameter) impacts the speedometer read-out, correct?

FWIW, I'm now running 255/55/18s on the rear and my speedo vs GPS is off about 1 mph.

[ctrlraven]

it was more somewhere between 135-140 with the 3.55's.
with the 4.10's it hit that 129 on the dyno @ Reinhart's place
I hit 149 mph on a dyno with 3.55 gears on 255/55-18 (3.50 effective rear gear).