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**N8N** · 05-19-2008, 03:42 PM

Older cars tended to cruise at a higher RPM than modern cars; "ideal" can mean many things. What are you looking for - performance, economy, quietness? I believe that a 4.xx was probably stock even with a 289/OD in later years. 3.73 or 3.92 at the lowest.

BTW if your shift linkage is sloppy you need to master the technique, when you shift out of first go past the neutral gate slightly to compensate for the slop (towards reverse) then pull it back down into neutral, *then* over to the 2-3 gate and up into 2nd. This will get you by at least until you can replace all the motor mounts and adjust the shifter properly.

good luck

nate

--
55 Commander Starlight

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**53k** · 05-19-2008, 04:08 PM

quote:Originally posted by Hippie

What is the 289's "sweet spot" as far as cruise RPM for the best highway fuel economy? I've finally settled on the 289 with a 200-4R swap and I need to select my rear end gears so I can order the speedo gears for the trans. ...

Later Stude V-8s with overdrive came with 3.73 rears- about 2000 rpm at 65mph. They just loafed at that rpm and speed. The '64 R-2 Avanti I had came with a 3.73 and automatic. It ran a little over 3000 rpm at 65. It was happy at that rpm (or higher), but I wasn't- too noisy. I changed it to a 3.07 and still had all kinds of power plus much quieter cruising. 289s have enough torque that they can pull away at 15 mph in high gear. So, I guess it's hard to identify a sweet spot.

[img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/R-4.JPG[/img=right][img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/64L.JPG[/img=right][img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/64P.jpg[/img=right][img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/53K.jpg[/img=right]Paul Johnson, Wild and Wonderful West Virginia
'53 Commander Starliner (since 1966)
'64 Daytona Wagonaire (original owner)
'64 Daytona Convertible (2006)
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1962 Gravely Model L (Studebaker-Packard serial plate)
1972 Gravely Model 430 (Studebaker name plate, Studebaker Onan engine)

**bige** · 05-19-2008, 04:55 PM

My car likes about 2400 RPM or 73 MPH. 700R4 with 3.73 and 215/75 tires. I got 22 MPG on the way home from Macungie a couple of years ago in 90 plus temps. I think you can dial in the sweet spot though. An R2 Avanti has maximum centrifugal advance at 1600 rpm at 24 total. Add another 10-12 with the vacuum and you have 36 total at cruise. So my guess is that my car gets more MPG at 2400 because the vacuum advance and total centrifugal are all in by then meaning the car likes to cruise at 36 degrees advanced.

Most naturally aspirated cars run a higher total advance but also at a higher RPM. Take that same car and put in an overdrive and the distributor curve no longer matches the factory setting for cruising RPM. So if it were me I would pick a gear ratio that would get me to the redline in third gear in a 1/4 mile and then I would find out what the factory set total advance including vacuum advance at for 3,000 rpm cruise and then curve the distributor to match cruising rpm with the overdrive.

You will also find the car will run cooler at the right amount of advance at cruise.

**PackardV8** · 05-19-2008, 05:30 PM

The nice thing about a 200-4R is it actually has five speeds. Properly setup, the torque converter unlocks in 4thOD at lower RPMs with more throttle opening.

If it were mine, I'd gear it to run 2,000 @ 60. There are many different governors, which determine the upshift points. The throttle valve (TV) cable determines downshift points.

thnx, jack vines

PackardV8

**Hippie** · 05-19-2008, 06:06 PM

quote:Originally posted by bige

curve the distributor to match cruising rpm with the overdrive.

You will also find the car will run cooler at the right amount of advance at cruise.

Something a lot of people don't consider when swapping in taller gears or OD.

Thanks guys, I know you can lose mileage just as easily by turning the engine too slow and dropping it out of it's torque curve so you're having to tip in the throttle for every little incline and breeze just to maintain speed so certain engines needing a little higher RPM than others makes total sense to me. Seen it for myself many times. 2000 @ 60 MPH seems toally reasonable. [8D]

Analog man in a digital world.

**Tom Bredehoft** · 05-19-2008, 06:37 PM

Not that my math is infallible, but I've figured with 215 - 75 tires and a 3.01:1 RA my 289 will be turning 2235 at 60 mph. Currently with a 3.54:1 it figures to be running 2577. (consider that it's 'way under construction, not running)

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Tom Bredehoft
'53 Commander Coupe
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**DEEPNHOCK** · 05-19-2008, 07:01 PM

An excellent question sure to pique interest and responses..
Here's my dime's worth...
You said 'sweet spot' and cruise speed in the same sentence.
Think about this.
You find out what the 'sweet spot' RPM is.
Emphasis on RPM.
Find it in each gear (ignore the car speed).
Then gear the car to run the speed you want in the 'sweet spot' in drive (1:1) or overdrive.
You might add a couple hundred RPM for wind resistance/friction loss, but you'll be mighty close.
Jeff[8D]

quote:Originally posted by Hippie

What is the 289's "sweet spot" as far as cruise RPM for the best highway fuel economy? <snip>

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**41 Frank** · 05-19-2008, 07:41 PM

On my R-2 with 200-4R and 4.09 rear gear and P225-15 tires it turns 2500 at 65mph

Frank van Doorn
1962 GT Hawk 4 speed
1963 Daytona Conv
1941 Champion R-2 Rod

**PackardV8** · 05-19-2008, 07:43 PM

FWIW an engine is most efficient at its torque peak, which on a Stude V8 is 2800 RPMs. I'd gear to run that at the highest speed I'd ever expect to hold a cruise. If turning 2kRPM@60, 2.8kRPM = 84MPH.

thnx, jack vines

PackardV8

**64Avanti** · 05-19-2008, 08:21 PM

Jack is correct about the most efficient point. However the torque curve with a standard cam (non R serries) is close to flat from about 2000 to 3200. It varries about 10 ft-lbs. For maximum fuel economy the throttle should be full open to reduce the pumping losses. Of course you can't gear car that high for say a speed of 70 or 75 mph because every time you hit a hill it would slow down and you would have to shift down.

In school I had a 1960 Hawk with a 4BL and a R1/R2 cam with a T86 with overdrive and a 3.73 rear axle ratio. That yields about 2.611 for a final ratio. With that ratio I used to get about 25 MPG at 70 to 75 MPH. It would pull to about 100 MPH in overdrive. If you wanted to go much faster you needed to shift out of overdrive. Anyway the 3.73 ratio worked out quite well.

David L

**Dick Steinkamp** · 05-19-2008, 08:23 PM

quote:Originally posted by PackardV8

FWIW an engine is most efficient at its torque peak, which on a Stude V8 is 2800 RPMs. I'd gear to run that at the highest speed I'd ever expect to hold a cruise. If turning 2kRPM@60, 2.8kRPM = 84MPH.

thnx, jack vines

PackardV8

Intuitively, I'm having a problem with this (but I've had bad intuition before

)

Here's maybe an extreme example...

The Stude engine is put in a 1500 pound car. It is geared to run 60 MPH at 2800 RPM and the fuel mileage is measured. It is then re-geared to run 60 MPH at 1800 RPM. Seems to me, it would get better fuel mileage in the second example than in the first.

**Hippie** · 05-20-2008, 04:32 AM

quote:Originally posted by Dick Steinkamp

quote:Originally posted by PackardV8

FWIW an engine is most efficient at its torque peak, which on a Stude V8 is 2800 RPMs. I'd gear to run that at the highest speed I'd ever expect to hold a cruise. If turning 2kRPM@60, 2.8kRPM = 84MPH.

thnx, jack vines

PackardV8

Intuitively, I'm having a problem with this (but I've had bad intuition before

)

Here's maybe an extreme example...

The Stude engine is put in a 1500 pound car. It is geared to run 60 MPH at 2800 RPM and the fuel mileage is measured. It is then re-geared to run 60 MPH at 1800 RPM. Seems to me, it would get better fuel mileage in the second example than in the first.

Ah yes, this is where the "fun" begins.

A lot of people think you want to be at peak TQ at cruise because that's where the are most efficient or attain maximum volumetric efficiency BUT they also use a lot more fuel at that RPM, they are just using less per HP or FtLb. and not that much less. From what I have seen both through research and personal experience is that you want to be just far enough into the torque curve that the engine has adequate output to maintain vehicle speed with enough extra to hold that speed on slight inclines and against a slight head wind with minimal throttle opening. There are a LOT of factors to consider, aerodynamics, weight, tire size, transmision and differential gear ratios and just as importantly the power CURVE of the engine. The more TQ and the lower the TQ curve in the RPM range the lower you can make the cruise RPM. I have read that some of the later 5.0 Mustangs actually got better mileage with lower (numerically higher) gears becasue they didn't quite have the low end TQ to pull the taller gear efficiently.

I had a 1967 Pontiac Catalina way back when with a Premium fuel 400-2V, TH400 and a 2.29 rear end. That 400 was a TQ monster, it could bury the speedometer in roughly a half mile but yet could pull 20-21 MPG at 65 MPH on bias-ply snow tires. This was a land barge tipping the scale in excess of 4400 Lbs. and had the aerodynamics of a grand piano standing on end yet it got decent mileage because it had a tall gear that let it "idle" down the highway and that worked because it had the low end TQ to pull down a barn. I'd love to duplicate that car today with a lower gear and a 200-4R to see what I could pull for mileage today with EFI and radials on it. I found a pretty decent '65 Bonneville 2 Dr. Hdtp. yesterday and if I didn't already have the Stude it would be in the garage right now. It's nearly as good as my Stude and he wants $600 or it goes to the crusher! [:0] I called a buddy of mine last night and he's going to give them a call today. We aren't going to let that happen. But, I digress........

A few years back I had a '92 LWB 2WD S-10 with a 4.3 TBI, 700R4 and 3.08 gears. A co-worker had the exact same identical truck except for color and 2.56 gears. Mine would leave his in the dust yet we both got the same identical mileage. We drove the same distance to work over nearly identical terrain with equal amounts of city and country driving and we both averaged 25-26 MPG. In fact it's those S-10's that has me thinking I can get away with a taller gear than what came in the Studes new. It has far better aerodynamics, is a couple hundred Lbs. lighter and according to a Desktop Dyno simulation the 289 makes 60 to 90 more FtLbs below 3000 and considerably more HP at higher RPM. My old S-10 was fun to drive and surprised a few V-8's, more than one guy wouldn't believe it didn't have a V-8 until I opened the hood, the gearing made all the difference.

Ther

**Jessie J.** · 05-20-2008, 06:48 AM

quote:Originally posted by Hippie

There's a happy medium between performance and mileage for every vehicle, I just have to find it. BUT every engine design has it's own "sweet spot" and what works for a Chevy 4.3 V-6 might not necessarily work for a Studebaker 289 but from what the ol' "butt dyno" ( aka "seat of the pants") tells me about the 289 it has enough low end grunt to comfortably cruise at 15 to 1600 RPM at 60 MPH which is right where the 200-4R and 3.42 gears will put me. My S-10 was cruising at about the same RPM but was carrying more weight and pushing a lot more air yet it still had plenty of passing power and got acceptable mileage. I think the ol' South Bend Bullet can do every bit as well. What do you guys think?

Analog man in a digital world.

I tend to agree, as one of the most satisfy all-around performing vehicles that I've owned was my Astro mini-van with the 4.3, 700r4 and the 3.43 geared "towing package". Strong acceleration from a standing start that would usually put me way out "ahead of the pack" on leaving intersections, and a comfortable cruise at anywhere between 60-80 mph.
The Astro gave me a decade of excellent service, finally sold it to my brother-in-law, and it probably would still be going strong if he had ever bothered with checking the engine oil level; yep, he ran it right dry and till he seized 'er solid.
I bought it back and removed the tranny and axle, which I am still holding onto for use in a future Stude project.
I'd prefer a 200-4R, but I got what I got.

**PackardV8** · 05-20-2008, 08:07 AM

FWIW, there are dozens of fuel mileage efficiency variables, including tire height, width, construction, carb vs. EFI, computer controlled ignition vs. mechanical distributor; and BTW, by contemporary standards even Stude Hawk and Avanti aerodynamics are a brick. Generalizing contemporary EFI computer vehicles and extending that to Stude V8 Conestoga wooden-wheel-era technology is not a rational exercise.

Another FWIW, the Chevy V8 [u]never</u> had any main bearing or crankshaft wear problems before computers. Then, when computer control kept the engine under heavy load, with the converter locked, down to 1500-1800 RPMs, problems began. This low-RPM lugging improved fuel economy and EFI and ignition computers would keep the engine smooth under that load, where carb and distributor would have it bucking. But this constant loading at low RPM led to the first main-bearing-related problems seen in the fifty-year history of the SBC engine.

That an engine is most efficient at torque peak is why I suggested gearing for torque peak at highest-likely cruising speed. If one wants to cruise at 84 MPH, then 2,800 RPM would be the crossover point where aerodynamics and efficiency intersect. Lower speeds require less throttle opening, because aero drag horsepower requirement goes up by the cube of speed.

thnx, jack vines

PackardV8

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