RE: IML: 'overdrive' details

["Rob P" <fristpenny@xxxxxxxxxxx>]

I agree that you might see diminishing returns if you have a high (low 
numerical) gearset, you should still see an improvement. Our 80's Imperials 
had 2.24 rears for mpg. I think it was due to the start of CAFE.  That's 
what necessitated the low first gear 998 (904) trans.  I'm sure the mileage 
is improved over a 2.94.  Is it worth $3k+ is the question?  It would take 
near forever to pay for itself.  I don't like the gearvendors because it 
doesn't give that much of an o/d.  I don't want to gear split.  I want my 
car set up right with an extra extremely high gear for cruise mpg.  I'm 
going to try to stuff an A500 mopar o/d in my car. They have a much bigger 
o/d than gearvendors, .68 I believe. That's easier for me because my 
Imperials are small blocks, so I don't have to deal with the bellhousing 
issue.  Of course I still have to deal with the trans tunnel and mount, but 
since my cars are thousands of miles away, it's fun to dream.

Rob


> From: "Rob McCall" <Rob_Mopar@xxxxxxxxxxx>
> Reply-To: mailing-list@xxxxxxxxxxxxxxxx
> To: <mailing-list@xxxxxxxxxxxxxxxx>
> Subject: RE: IML: 'overdrive' details
> Date: Wed, 26 Jul 2006 22:42:26 -0400
>
> I haven't tried it yet, but I am heavily considering it for my '04 Diesel
> Ram and my '68 Barracuda.  In the Ram with 4.10 gears, even in 6th it is
> turning the motor too high for sustained highway use.  It has more than
> enough guts, but the mileage drops like a rock.  At 55 MPH and below it's
> happy.  Over 55 and goodbye $$$.
>
> The GV unit allows gear splitting, i.e. 1st gear/1st gear in overdrive,
> 2nd/2nd overdrive, etc.  With the stick shift in the truck, I can see this
> being handy.  With an automatic, not as handy.
>
> Now the real question is what rear gear ratio do you have now?  If you are
> still running the stock gears, I do not think you will see much of a
> difference in mileage.  A 2.94 rear gear in overdrive is the equivalent of 
> a
> 2.29 rear gear.  If you are planning a run to the salt flats, that might be
> a good ratio.  If you are running 3.55's, it will drop it down to a 2.77, a
> nice highway gear ratio.  3.91's drop down to a still highway friendly 
> 3.05.
>
> I have a spreadsheet at work that I was playing around with during 
> lunch(es)
> this week calculating RPMs based on MPH, rear gear ratio, and tire 
> diameter.
> If I remember to send it home tomorrow, I'll be glad to share it with 
> anyone
> who is interested.
>
> Other than cutting the driveshaft, the transmission tailshaft housing is
> replaced with the GV adapter and the overdrive unit bolts to it.
>
> Rob McCall
> '67 LeBaron, probably 2.94 gears.
>
> -----Original Message-----
> On Behalf Of Damian Justice
>
> yessir, you have to cut, or replace the driveshaft.  They have
> under/overdrive if you are intrested in a quick takeoff followed by high
> speed/low rpm.  I am only intrested in low r's on the highway.  I guess
> nobody has tried it yet.
>
>
>
>
>
>
> -----------------  http://www.imperialclub.com  -----------------
> This message was sent to you by the Imperial Mailing List. Please
> reply to mailing-list@xxxxxxxxxxxxxxxx and your response will be
> shared with everyone. Private messages (and attachments) for the
> Administrators should be sent to webmaster@xxxxxxxxxxxxxxxx
> To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm




-----------------  http://www.imperialclub.com  -----------------
This message was sent to you by the Imperial Mailing List. Please 
reply to mailing-list@xxxxxxxxxxxxxxxx and your response will be 
shared with everyone. Private messages (and attachments) for the
Administrators should be sent to webmaster@xxxxxxxxxxxxxxxx
To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm