Posted by Charlie on Saturday, August 04, 2001 at 2:33AM :
In Reply to: 4BT not enough power posted by Dave on Friday, August 03, 2001 at 10:18PM :
What kind of truck are you talking about? If a WDX/WM300/B1PW type flatfender PW then a 4BT is your only choice and will have more than enough power for 4.89s, overdrive 5 or 6 spd and 36-39" tires. If you want to soup up a 4BT more you can with some 6BT go-fast parts including an inexpensive Powershot 2000 propane kit with a forklift tank in the back.
Just remember that "gearing is everything". A 4BT in a flatfender should be geared so that top speed (25-2600 rpm) is 75-80 mph in highest gear. There's no need for faster gearing, a flatfender even with disk brakes and radials really isn't comfortable at >65-70 mph in other words 2-400 rpm below peak.
To harness the torque a closer ratio transmission is MUCH better i.e. try to use a NV5600 instead of a 4500.
For the humoungous W300 of the 60s I think a 4BT could be made to work but anything short of a 6spd would labor on upshifts. A 6BT OTOH would work well with NV4500 and be a hot rod with a NV5600. The basic measurement is back of radiator to front of firewall, minus front of fan to back of cylinder head. This difference should preferably be 3-4" or more. If not, an electric pusher fan can be mounted on front of the radiator etc. but things start becoming problematic.
As far as weight in a Dana 60 equipped W300 I think just attention to springs and spring height can rectify problems. but still take into account gearing, even with a 6BT. I think with the 6 spd one could be a bit liberal and gear 6th for 90-95 mph, thus achieving 1800-2000 rpm at 70 in 6th. That would be a strain for the 4BT.
With a diesel swap of either enine make sure you are gearing the rig for your final tire setup, use a total systems approach, it saves money and effort and heartburn in the final accounting. If in doubt always pick the numerically higher gear ratio, you can always put bigger tires on but who wants to put smaller tires on???
Charlie
|
Follow Ups:
This board is powered by the Mr. Fong Device from Cyberarmy.com |