Log in

View Full Version : More gear talk



Rkammer
06-09-2005, 07:38 PM
I've read most of the old posts re: 4:10 gears so I understand the rationale and benefits. However, I'm wondering if anyone who just doesn't want to go all the way to 4:10s has tried the 3:90 gear set? It's about 2/3 of the way from the 3:55s to the 4:10s so should give most of the benefits while maybe buying back about 100 RPM on the highway. I realize there's not much difference from 3:90 to 4:10 but I'll be towing my boat around the state and fuel mileage won't be that good anyway. I"d like to obtain as much fuel mileage as possible while still deriving some benefit from a gear change. Any thoughts?

rumble
06-09-2005, 07:42 PM
I've read most of the old posts re: 4:10 gears so I understand the rationale and benefits. However, I'm wondering if anyone who just doesn't want to go all the way to 4:10s has tried the 3:90 gear set? It's about 2/3 of the way from the 3:55s to the 4:10s so should give most of the benefits while maybe buying back about 100 RPM on the highway. I realize there's not much difference from 3:90 to 4:10 but I'll be towing my boat around the state and fuel mileage won't be that good anyway. I"d like to obtain as much fuel mileage as possible while still deriving some benefit from a gear change. Any thoughts?

Maybe tihis 'll help

http://www.averagegeek.com/Evil_Jim/GearCalc.asp

FordNut
06-09-2005, 07:46 PM
I've read most of the old posts re: 4:10 gears so I understand the rationale and benefits. However, I'm wondering if anyone who just doesn't want to go all the way to 4:10s has tried the 3:90 gear set? It's about 2/3 of the way from the 3:55s to the 4:10s so should give most of the benefits while maybe buying back about 100 RPM on the highway. I realize there's not much difference from 3:90 to 4:10 but I'll be towing my boat around the state and fuel mileage won't be that good anyway. I"d like to obtain as much fuel mileage as possible while still deriving some benefit from a gear change. Any thoughts?
Check out this:
http://www.mercurymarauder.net/forums/showthread.php?t=17659

MM03MOK
06-09-2005, 07:48 PM
I've read most of the old posts re: 4:10 gears so I understand the rationale and benefits. However, I'm wondering if anyone who just doesn't want to go all the way to 4:10s has tried the 3:90 gear set? It's about 2/3 of the way from the 3:55s to the 4:10s so should give most of the benefits while maybe buying back about 100 RPM on the highway. I realize there's not much difference from 3:90 to 4:10 but I'll be towing my boat around the state and fuel mileage won't be that good anyway. I"d like to obtain as much fuel mileage as possible while still deriving some benefit from a gear change. Any thoughts?Mikeenh should pipe in here....he tows his Airflow and Model T (not at the same time ;) ) with 4:10 gears installed in his MM.

huot5
06-09-2005, 08:15 PM
:bandit: If your're planning on going with smaller diameter rear tires ; i.e. 245/45's, 4:10's will feel more llike 4:30's. The geek gear calc should help you out. I almost went with 3:90's but I got a brand new set of 4:10's on ebay for 115.00 in Dec 04...:rasta: :beer: Cheers.

Rkammer
06-09-2005, 08:34 PM
Looks like 3.90s are defininitely an option for my application. Thanks for the references to other threads. :burnout:

BillyGman
06-09-2005, 11:39 PM
Just some thoughts of my own here incase you haven't already made a decision on this. And the following thoughts are based on my use of three different gear ratios in my own Marauder which took place before my car was ever supercharged (started w/the stock 3:55's, then went to the 4.10's, and now I have the 4.56's):


Because these are heavy cars, it really takes a significant gear ratio change to make a big enough difference for you to actually feel on the street when you hit the go pedal. So my thoughts on this are that you should consider what Mary ( aka "MM03MOK") stated in her post. I can understand your logic in wanting to compromise with the choice of gear ratio, but unfortunately, with an N/A Marauder being as heavy as these cars are, if you compromise that much w/the gear ratio, you might very well find that you'll end up with a jack of all trades, master of none, and therefore not feel any difference in the acceleration at all. It might only be enough of a change that can be measured w/electronics in the quartermile run, rather than by the seat of the pants. Again, just some thoughts from my point of view. Whatever choice you make, I do hope that you're happy with it. Because I know how it is to perform a gear change, and then have to do it all over again because you're not satisfied w/the results, and you therefore want to go w/another ratio. Good luck. ;)

Rkammer
06-10-2005, 03:08 AM
Just some thoughts of my own here incase you haven't already made a decision on this. And the following thoughts are based on my use of three different gear ratios in my own Marauder which took place before my car was ever supercharged (started w/the stock 3:55's, then went to the 4.10's, and now I have the 4.56's):


Because these are heavy cars, it really takes a significant gear ratio change to make a big enough difference for you to actually feel on the street when you hit the go pedal. So my thoughts on this are that you should consider what Mary ( aka "MM03MOK") stated in her post. I can understand your logic in wanting to compromise with the choice of gear ratio, but unfortunately, with an N/A Marauder being as heavy as these cars are, if you compromise that much w/the gear ratio, you might very well find that you'll end up with a jack of all trades, master of none, and therefore not feel any difference in the acceleration at all. It might only be enough of a change that can be measured w/electronics in the quartermile run, rather than by the seat of the pants. Again, just some thoughts from my point of view. Whatever choice you make, I do hope that you're happy with it. Because I know how it is to perform a gear change, and then have to do it all over again because you're not satisfied w/the results, and you therefore want to go w/another ratio. Good luck. ;)
Billy, Thanks for the thoughts. I'm very familiar with the effect gear changes can make on both accelloration and fuel mileage although not with cars as heavy as the MM. I think a gear change of almost .5 (3.90s) should provide enough of a performance gain that I'll feel it SOTP but if it's only evident in the 1/4 mile time slip then that's OK too. That's how I measure performance gains anyway. But, even if I have to change the gears a second time, all I've lost is the labor to install the 3.90s and that's only about $150 with the shop I use. Worth the gamble for the compromise I'd be making IMO. But, we'll see how I feel after I get the car home and see what the SCT tune and other mods do for the 1/4 mile times. I may just want to leave the 3.55s in there. As I've said previousy, if I want to go really fast, I'll drive my Turbo Buick. The MM is the family cruiser.

dwasson
06-10-2005, 07:22 AM
My wife would say that this proves that men have a fear of commitment.

Captain Steve
06-10-2005, 07:35 AM
A gear change of ".5" isn't a good measure. It's different depending on what you're talking about. For instance, a change from 1:1 to 1.5:1 is alot different than a change from 5:1 to 5.5:1.

Here's a way to look at it that may help more.
3.90 = 1.0985915492957746478873239436 62
3.55

4.10= 1.1549295774647887323943661971 831
3.55

So, if you are now doing 2000 RPM with 3.55 gears, you would be doing 2197 RPM with 3.90 gears and 2310 RPM with 4.10 gears.

At 4000 RPMS with 3.55 gears that becomes 4394 w/ 3.90s and 4620 w/ 4.10s.

Most of us cruise on the highway at a maximum of around 2500 RPM with 3.55s. With the 3.90s that would mean 2746 RPM and with the 4.10s 2887 RPM.

So, you can see, there isn't much difference between the two on the highway as you would think. At highway speeds (2500RPM or ~75mph)you're talking about 141 rpm difference between the 3.90s and 4.10s.

RF Overlord
06-10-2005, 07:50 AM
I think a gear change of almost .5 (3.90s) should provide enough of a performance gain Actually it's a difference of .35, not .5

In conversation with Steve Babcock at MVII, he told me they originally spec'd the car to have 3.73s or 4.10s from the factory, but it turned out that would put the car into the Gas-Guzzler tax, so they dropped to the 3.55s (among other changes)...my point is that you may be perfectly happy with 3.90s. They may be a good compromise between maintaining fuel ecomomy and having better performance, especially if you can get gear swaps for only $150...most of us had to pay double that, so we didn't want to risk not being worth it.

ckadiddle
06-10-2005, 07:59 AM
I am grossly gear ignorant, folks, enlighten me here. I know 4.10s are good... if I don't give a flip about gas mileage, are there even steeper gears that will fit the 2003 Marauder?

Doobie1
06-10-2005, 08:09 AM
I am grossly gear ignorant, folks, enlighten me here. I know 4.10s are good... if I don't give a flip about gas mileage, are there even steeper gears that will fit the 2003 Marauder?
6.27's :rasta:

Captain Steve
06-10-2005, 08:12 AM
Here's a way to look at it that may help more.
3.90 = 1.0985915492957746478873239436 62
3.55

4.10= 1.1549295774647887323943661971 831
3.55

So, if you are now doing 2000 RPM with 3.55 gears, you would be doing 2197 RPM with 3.90 gears and 2310 RPM with 4.10 gears.

At 4000 RPMS with 3.55 gears that becomes 4394 w/ 3.90s and 4620 w/ 4.10s.

Most of us cruise on the highway at a maximum of around 2500 RPM with 3.55s. With the 3.90s that would mean 2746 RPM and with the 4.10s 2887 RPM.

So, you can see, there isn't much difference between the two on the highway as you would think. At highway speeds (2500RPM or ~75mph)you're talking about 141 rpm difference between the 3.90s and 4.10s.<!-- / message --><!-- sig -->



I think 4.56s are the lowest anyone has gone. BillyGman has them and will probably tell you that they're great on the 1/4 mile track, not so great on the highway mileage.

Let me apply the formula I used in my first post in this thread to compare.

4.56 =1.284507042253521126760563380 2817
3.55

So:
3.55 @ 2000 RPM = 4.56 @ 2569 RPM
3.55 @ 2500 RPM = 4.56 @ 3211 RPM
3.55 @ 4000 RPM = 4.56 @ 5138 RPM

BillyGman
06-10-2005, 10:37 AM
I am grossly gear ignorant, folks, enlighten me here. I know 4.10s are good... if I don't give a flip about gas mileage, are there even steeper gears that will fit the 2003 Marauder?Yeah, I have the 4.56's like I've already stated. There are also 4.88's, and 5.13's(which are the tallest available for this rear) for the Ford 8.8" rear (which is what Marauders have). But 5.13's or even 4.88's would only be good for a Marauder that isn't driven on the highway, and is strictly for the 1/8 mile drag race.

'03BlkMM
06-10-2005, 10:44 AM
I'm quite happy with the 3.90's. The 10% gearing advantage they give you is very noticeable by the SOTP meter. Its basically the same thing as picking up 10% torque across the entire RPM band. Would you feel a 30 lb/ft torque increase in a 4000+ lb car, if you don't your butt meter is broken. But it sounds like your about to do the flasher which will give you a definite boost in performance as well. You may be happy with that alone, I almost was, I just wanted a little bit more! :D

Smokie
06-10-2005, 10:55 AM
But, we'll see how I feel after I get the car home and see what the SCT tune and other mods do for the 1/4 mile times. I may just want to leave the 3.55s in there. As I've said previousy, if I want to go really fast, I'll drive my Turbo Buick. The MM is the family cruiser.Tuning can make our cars very responsive and can satisfy a lot of people. Something to consider is whether you plan on making more changes down the road. Some mods compliment others, others don't.

I have an entry in the timeslip page of what is possible with only tuning (nothing else) if you care to, check it out and see if this is something that you would find acceptable, my gas mileage improved with tuning.:)

BillyGman
06-10-2005, 10:59 AM
I'm quite happy with the 3.90's. The 10% gearing advantage they give you is very noticeable by the SOTP meter. Its basically the same thing as picking up 10% torque across the entire RPM band. Would you feel a 30 lb/ft torque increase in a 4000+ lb car, if you don't your butt meter is broken. Well then mine must be "broken" because I felt very little change just by driving my Marauder on the street when I went from the 3.55's to the 4.10's. However, I don't think my "butt meter" can be all that "broken" because I sure felt a collosal difference in acceleration when I drove the car after installing the supercharger. Going from 3.55's to 3.90's will only give you a 200 RPM difference at 70 MPH in O/D, and a 300 RPM difference at 70 MPH in third gear(O/D off). And an RPM increase that's that small even at highway speeds isn't going to give you very much of a mechanical leverage advantage off of the starting line with a 4,200 LB car pushing only 240-250 HP at the wheels.

I think a lot of people spend the money, and perform a modification, and therefore they want to believe so much that their car is so much faster, and that it can be felt on the street just by pushing the go pedal that they convince themself that they can notice it simply because they don't want to admit to themself that they've spent the $$ to make their car more enjoyable to drive for nothing, and that it yielded a very minor change. One much more minor than they were looking for. Than there are others who perform several modifications at once, and they do notice a very substantial difference in the way their car accelerates, but they tend to forget that it wasn't the gears and the tune alone that accomplished that. To each his own.

duhtroll
06-10-2005, 11:59 AM
Weird. I felt a SOTP difference between a MM with 4.10s and one with 4.30s.

Your butt-o-meter must be broken. :D

-A

'03BlkMM
06-10-2005, 12:23 PM
Well then mine must be "broken" because I felt very little change just by driving my Marauder on the street when I went from the 3.55's to the 4.10's. However, I don't think my "butt meter" can be all that "broken" because I sure felt a collosal difference in acceleration when I drove the car after installing the supercharger. Going from 3.55's to 3.90's will only give you a 200 RPM difference at 70 MPH in O/D, and a 300 RPM difference at 70 MPH in third gear(O/D off). And an RPM increase that's that small even at highway speeds isn't going to give you very much of a mechanical leverage advantage off of the starting line with a 4,200 LB car pushing only 240-250 HP at the wheels.

I think a lot of people spend the money, and perform a modification, and therefore they want to believe so much that their car is so much faster, and that it can be felt on the street just by pushing the go pedal that they convince themself that they can notice it simply because they don't want to admit to themself that they've spent the $$ to make their car more enjoyable to drive for nothing, and that it yielded a very minor change. One much more minor than they were looking for. Than there are others who perform several modifications at once, and they do notice a very substantial difference in the way their car accelerates, but they tend to forget that it wasn't the gears and the tune alone that accomplished that. To each his own.
I sure would hope you could feel a difference with a SC on the car!
I would say your butt meter must need recalibrating if it couldn't tell much if any difference with 4.10's. I doubt that many people would say that they could not tell much of a difference once they installed 4.10's in their MM.

Sure there is not a huge difference at highway RPM's in O/D. But I can feel a difference at highway RPM's between the 3.55's in O/D and the 3.90's. But When I'm at WOT in 1st gear and revving 6000rpms the 3.55 geared car is still at 5400 rpm's. That is a somewhat significant difference in RPM's. Is it as much as a 4.10 geared car or your 4.56 geared car, NO. But it is enough of a difference to be felt by "my" SOTP meter and should make a nice difference when towing a boat. The original poster didn't ask if his 0-60 or 1/4 mi times would improve by the way.

Brutus
06-10-2005, 02:37 PM
some more info......




http://www.mercurymarauder.com/forums/showthread.php?t=7214&highlight=bored+work

Smokie
06-10-2005, 02:44 PM
some more info.....Hey, it's been awhile, the Mrs. doing well? Getting close right?:2thumbs: