With the 'new' 2.88 diff, the 300td shifts like butter -- can barely feel them. And I made no tranny adjustments.

I'm just guessing at the 1 mpg, but, generally, the SD's do slightly better due to the better Cd of the body.

Well, you might consider an adjustment to get it to shift "crisply" if you wish the maximum life from the transmission. "Butter" translates into extra clutch wear.

Cold butter (not margarine) would be ok but, not warm butter. ;)

How would the prechambers effect fuel economy?

Scott

If the shaft falls out of the prechamber, the fuel isn't atomized properly and efficiency is lost.

Wow, my car must be in great tune because I got 28.2 with my last tank. As long as I keep the speed consistent - not trying to speed up and pass people with a lot of throttle, and keep it under 75 mph, I consistently average above 27 mpg. Road trip last month to my sister's - north Jersey to Lewes, Delaware. Return trip took me up 95 thru Philly because of traffic at the Del Mem bridge, across Jersey on the A/C Expressway and back up the GS Parkway at "speeds over 75 mph", windows and roof open on a 90+ degree day, I got 27.6 mpg on that tank. Over 500 miles and it only took 17.5 gallons when I filled it. I assume my 83 has the 3.07 rear ?

Are you talking about the ball at the end of the prechamber? If that breaks off, doesn't it fall into your cylinder and destroy your engine? Where does it go?

Thanks,

Scott

It's a through shaft with an elarged central portion that some folks characterize as a "ball".

It doesn't break off.........the shaft fails in the prechamber wall. If it falls out of the prechamber, it sits in the bottom of the prechamber and partially blocks the exit holes from the prechamber...........resulting in poor combustion in that cylinder.

Those are fantastic numbers with a 3.07 if the speeds are correct. They are usually not attainable at 75 mph. In fact, I'd be fortunate to achieve them with the 2.88 in the SD if I drove it that fast.

Hmmmm, interesting. I'll have to firm up the shift points a bit.

I have a 2.47 rear
 

I am going to have my guy install it before heading to Washington. I will check back with any mileage improvements. I am installing it mainly to get the RPMs down at 75mph. I got mine from eBay a year ago, for I think 80 bucks, but have not installed it. I think I will have my indy do it on his lift rather than trying to do it on jack stands.

I'll be curious to see how you fare on the typical hills in NY. I don't think you'll be able to climb certain highway grades at 65 mph in fourth.........you can certainly forget about 75 mph. But, a 4-3 forced downshift should clear up the problem..........I'm interested in the first time you need to do this. The engine will be turning about 3700 rpm in third which will offer plenty of horsepower.........and a bit of racket.

That was one reason I have been holding off on the swap. Of course I will be keeping the 3.07 so if it is too bad I can always swap back. I am thinking about doing it before moving to Va. I won't be climbing the Catskills any longer! Any hill climbing will be done on back roads so I should be OK.

I will let you guys know of my experience as soon as it is done.

Could you increase your top speed by quite a bit with a 2.47 or is there just not enough power to fight drag after a certain point in 4th gear to make a difference?