The 40MPG Crown Victoria Challenge

[Big Dave]

M-B 5 speed manuals are notoriously hard to come by in North America.

Do you have a pen pal in Germany?

Being lighter, the OW 617 would be a good choice. The Crown Vic is too heavy for a VW TDI.

The T-56 is easy to find. They have been used in Mustangs, Canaros, Corvettes, Vipers, etc.

[comptiger5000]

Honestly, if 40mpg highway is the goal, give it TALL gearing (aim for about 1350 - 1400 rpm at 60mph), lower it and aeromod it, and you should be able to get there. However, that won't help city mpg much. But if it's primarily a long trip car, it'll get the job done.

[roflwaffle]

My 3L engine probably needs ~1500rpm just to get into a decent area of the BSFC curve, so I'm not sure if gearing it taller would even be practical w/ a 4.6L engine. I think an engine/trans swap and the basjoos aeromod treatment would be needed to get to 40mpg highway.

[mystere485]

Originally Posted by Big Dave

M-B 5 speed manuals are notoriously hard to come by in North America.

Do you have a pen pal in Germany?

The T-56 is easy to find. They have been used in Mustangs, Canaros, Corvettes, Vipers, etc.

this is the list i saw for the t-56, i totally skipped over the camaro.

Aston Martin DB7 Vantage, 1999–2003
Aston Martin V12 Vanquish, 2001–2006
Chevrolet Corvette, 1997–2007
Chevrolet Camaro, 1993-2002
Dodge Ram SRT10, 2004–2006
Dodge Viper, 1992–2007
Ford Mustang Cobra, 2003–2004
Ford Mustang Cobra R, 2000
Ford Falcon XR6, XR6T, XR8
FPV F6 Tornado/Typhoon, GT/GT-P 2004–2008
General Motors GM F platform V8 cars, 1993–2002
Holden Commodore 1998–2008
Holden Monaro, 2001-2006
GM M12
2001–2004 Chevrolet Corvette Z06
2004–2006 Pontiac GTO
2004–2006 Cadillac CTS-V
GM MN6
2004–2007 Chevrolet Corvette
GM M10
2005–2006 Chevrolet SSR
2006–2008 Holden VE Commodore
GM MZ6
2005–2007 Chevrolet Corvette Z51

I was like, where am i supposed to find any of these cars in wreckers?

Of all things theres an e-class 300td wagon in the PYP here with a 5 speed. The engine I was told was shot, but otherwise the car looks ok.

Originally Posted by comptiger5000

Honestly, if 40mpg highway is the goal, give it TALL gearing (aim for about 1350 - 1400 rpm at 60mph), lower it and aeromod it, and you should be able to get there. However, that won't help city mpg much. But if it's primarily a long trip car, it'll get the job done.

Yes, long, long trips. One way home is 1300kms, we have the del sol for city driving.

[comptiger5000]

A 4.6 should be ok down to 1400 or so. Probably don't want to go lower, and 1500 would still be ok. The big reason for the taller gearing is to keep enough load on it with the reduced aero drag from the basjoos treatment.

Long tube headers tuned for maximum low end torque, and certain other engine tweaks might help it turn very low rpms comfortably and efficiently on the highway. Big engines are only a true killer around town, on the highway, they just need a very different set-up than small engines.

For example, my grandfather used to have a late 80s / early 90s V6 S10 (not sure which V6) with a 5 speed. He now has a late 90s I4 S10 with a 5 speed. He says that while the V6 had much more power, they both get the same gas mileage on the highway (the 4 is a little better around town), with the V6 doing even a little better in the hills. Basically, for a larger vehicle, a small engine can require such low gearing compared to a larger one that it's no more efficient in steady state cruising.

[roflwaffle]

At 1500rpm/60mph I'm pretty sure a 4.6L will still be in the ~350+g/kWh region, at least after the aeromods. It might be at ~250g/kWh stock, but w/o the aeromods I doubt it'll see 40mpg.

[comptiger5000]

I agree, it will need aeromods to hit 40mpg. My point is that aeromods and tall gearing together will do far more than just aeromods, as a very lightly loaded engine revving higher than it needs to gets crappy mpg (hence why the 360 in my Jeep needs a tailwind to hit 20mpg on the highway, as it's just not geared tall enough).

[roflwaffle]

In this case I think the problem is that after aeromods a 4.6L engine running at ~1500rpm will still be in a crummy portion of the BSFC map (~350+g/kWh). In order to get into a nicer portion taller gearing (~1000rpm@60mph) or a smaller engine would probably be required.

[darcane]

Originally Posted by roflwaffle

In this case I think the problem is that after aeromods a 4.6L engine running at ~1500rpm will still be in a crummy portion of the BSFC map (~350+g/kWh). In order to get into a nicer portion taller gearing (~1000rpm@60mph) or a smaller engine would probably be required.

Fuel consumption goes to zero when the engine is off. 40mpg will require hypermiling, and that's tough with an auto. There's no way he'll get there without a manual tranny.

The TR-3650 came in Mustang GTs and has as high as a 0.62:1 OD. That would help and should have the same bolt pattern as the 4.6L in that Crown Vic.

[roflwaffle]

He can maybe get to 40mpg highway w/ an automatic/rear end w/ super tall gearing and an override for the tcc, but there's no way he could average that in the city. Ideally we would all have access to 6+ speed manual gearboxes w/ all sorts of super tall ratios so we wouldn't need to P&G, but in the real world you're pretty much spot on in terms of city driving.