Bob Tom <tigers@bserv.com> wrote:
: Hi
: At the track, I am currently running with 3.92 gears, 26" drag tires
: 44RE auto. and a 3000 (flash) stall converter with a total race weight
: of 4,080 lb. Prior to my diy ported heads, a dyno. showed that my
: peak hp was 5000 rpm. With my current setup, I'm going through the
: traps at around 5000 rpm or so.
[...]
I did some calculating here - I needed something to wake myself
up this morning anyway :-) - and here's what I came up with...
Using your stated info of going through the traps at 5,000rpm with
3.92s on 26" drag tires, I calculated that your MPH is about 98.66.
Assuming that you made no other changes except for the 4.56s, and
assuming that you run that same MPH, that would raise your RPMs to
5816. If you were then to swap the 26" tires out for 28", still
keeping the 4.56 gears and assuming the same MPH, your RPMs would
be 5400. All of the above assumes you are going through the traps
in 3rd gear as opposed to OD.
: How are the 4.56 gears in street and highway driving? I know the
: OD is a great compensator for low gears but is it enough for 4.56s?
: I'm old enough to have owned and driven mopar muscle cars in 70
: and 71 to be comfortable with 3000 rpm at 70 mph. My street tires
: are 28"ers.
If my calculations are correct, your current RPMs at 70 in OD
with 28" tires would be about 2270 (3300 in 3rd). If you were to
swap out the 3.92s for 4.56s, that would put your 70mph OD rpm at
2644 (3832 in 3rd). Oh, I assumed an OD ratio of 0.69:1, based
on the DML FAQ data for the 46RE - I just assumed the 44RE would be
about the same. So, you'd be cruising around at just over 2600rpms -
seems pretty decent.
As far as the muscle cars at 3,000rpm at 70 go, the cuda runs
3,000rpm at about 55mph with 3.91s - maybe I need a taller tire. :-)
I actually looked into trying to find a third member with a 2.73 or
something along those lines until I saw the $900 price tag. Could always
go the Gear Vendors OD route, but that's $2,000. Oh well, I guess I'll
just have to buzz around locally and keep it off the highway.
---Jon-
.---- Jon Steiger ------ jon@dakota-truck.net or jon@jonsteiger.com -----. | I'm the: AOPA, DoD, EAA, NMA, NRA, SPA, USUA. Rec & UL Pilot - SEL | | '70 Barracuda, '92 Ram 4x4, '96 Dakota, '96 Intruder 1400, '96 FireFly | `----------------------------------------- http://www.jonsteiger.com ----'
This archive was generated by hypermail 2b29 : Fri Feb 06 2004 - 11:47:17 EST