Re: New Christy Rambler (Ebay)

[Tom Jennings <tomj@xxxxxxx>]

On Nov 2, 2005, at 1:24 PM, <mail@xxxxxxxxxxxx> wrote:

> IIRC my tires [25560R15] are about 26.5 tall and I have a Spirit  
> T-5 with 3:31 gears. It cruises on the highway just great. I have  
> no real idea of what RPM it pulls as I've never mounted a tach.  
> Fuel Mileage? I've not checked it offically, but it is real good,  
> I'd estimate 25-30 mpg highway easy. I wish I could drive it more  
> to get and official read on it. The 3:31's seem to be about perfect  
> with my current combo.

Yours is turning 2500 at 60, 2900 at 70; mine's somewhat less, 2200  
and 2550 or so. (see below)

I'd be really interested in hard mileage data on your car. I'm  
getting a solid 22 mpg highway at 60 - 65 mph, 19 mpg at 70 - 75 mph,  
and around 18.5 in-town. That's 7800 miles, 400 gals of data (every  
single fillup and mile since I ran the car in June 2005. I drive 300  
mi/week (100 mi/day 3 days) on I5, I605, I405, LA to Irvine.

Long ago we had a thread about mileage, engine efficiency, cruising  
'sweet spot', torque peak, etc. Never got resolved to my  
satisfaction. The old and general consensus is that best mileage is  
under 2000 rpm, and that torque peaks are spec'd under 2000 rpm for  
the motors AMC used. Clearly, you and I, and nearly all of the  
numbers I've seen in TSMs regarding GEARING (not engine rpm/hp/torque  
specs...) puts 60 - 70 mph cruise will over 2000 rpm.

I don't believe the TSM engine torque and HP specs, at all. Net or  
gross, it's half marketing and tax issues. I'd love to hear actual  
dyno numbers on actual factory-stock motors, but I don't think many  
people do that.

Clearly gearing is all a compromise even in the fuel-spree 60's, but  
still, factories tended to know what they were doing, if only be  
large-scale trial and error.



Mark's car,  hacked up from my Hornet spreadsheet, I included on 3rd  
gear (1:1).


		RPM	CFM	MPH		TIRE DATA	
			1000	60	24.3		
Axle ratio n:1	3.31	1100	66	26.7	Width:	255
Tire diameter	27.05	1200	72	29.2	Aspect:	60
			1300	78	31.6		Wheel:	15
			1400	84	34.0	Diameter:	27.05
			1500	90	36.5			
			1600	96	38.9			
RPM interval	100	1700	102	41.3			
			1800	108	43.8			
904 Auto		1900	113	46.2			
First	2.54		2000	119	48.6			
Second	1.55		2100	125	51.1			
Third	1		2200	131	53.5			
			2300	137	55.9			
			2400	143	58.3			
Engine CID	258	2500	149	60.8			
VE	0.8		2600	155	63.2			
			2700	161	65.6			
			2800	167	68.1			
			2900	173	70.5			
			3000	179	72.9			
			3100	185	75.4			
			3200	191	77.8			
			3300	197	80.2			
			3400	203	82.7			
			3500	209	85.1