In your opinion, what drive-line combo makes for the best balance of power WITH good gas mileage? Could be just about anything from say a GN to a fuel injected 455. Please include the rear gear ratio as well. Looking forward to hearing about your experiences.:Smarty:
If I were trying for the perfect balance and cost was no object, I'd go with a gearvendors overdrive stuck to the back of a 700R/4L60 and a pretty short rear, like a 3.73:1. Then you'd have two overdrives you could switch on and off, so you'd be geared super-tall when you wanted economy or super-short when you didn't. Take a look at the ratios here: http://www.gearvendors.com/hrgmratios.html With an 11.41:1 final drive in first gear and a 2.04:1 final drive in top gear with both overdrives, that really is the best of both worlds, in my opinion.
I am pretty sure they don't make a Gearvendors for a 700r4, and even if they did it is not needed. One overdrive unit is enough. Try cruising down the interstate at 1000rpm. Your engine will hate you and your mileage won't be very good.
Hmm, I see they actually do make a Gearvendors for a 700r4. Strange. Still, you would never recoup your investment with gas savings.
Pretty hard to beat a gn done up. Mine runns 11s and still gets 25 miles per gal. trans is the weak link.
Jetta tdi gets about 40-50 mpg without any upgrades or anything. As for my cars I'm always in a fullsize GM (b/c/d-body) and I always end up at 20mpg regardless of the year of the car or the engine in it, as long as it has an OD trans (2004r or 4l60e). My current 455/th400 is getting well below that number. I'm using almost a quarter tank to travel 40 miles which is something like 9 mpg or so.
With my 96 Roadmonster I'd generally get around 20 commuting and driving around town, but close to 30 with the cruise set at 75 on the interstate.
I believe the back of a 700 and a 350 are the same. so its probably made for the 350, but works with the 700. too low of an rpm is worse than too high....
Well best I can tell without actually checking, I'd say I'm getting about 15-16 with the Skylark. Being that it came with a 231, it has more gear than most of the GM products I've had. Needs overdrive bad! I need to get some 15's with some 235 75 R15 till I can run across a 200R4!
I could get 20mpg in my 71 Chevelle with a 307/TH350 with just an HEI ignition in it. Once this Riv project gets going, I have a 200-4r for the 455 and an idea for a Mega Squirt fuel injection setup. Hoping I can get mid 20's at least.
I've had quite a few Chevelles that pulled 20 or close to it. Most of them either had 2:56's or 2:73's. I think the Skylark has 3:36's being a V-6 car? I'd like to find a modern day version of the 215 and mate it up with a 200R4 and then go turbo. Might have a line on one. I think it's a 4.2, but not sure. I wonder how much Land Rover changed the bellhousing. That would be fun in the Skylark!
The ultimate swap for the best fuel mileage and still be "all Buick" is: 27" tall tires, 3.42 gear, 2004R trans with lockup torque converter, and a 87 Turbo 3.8 engine, all tuned with a megasquirt computer. Should be able to get 25+ MPG. Or if you want do something like I am doing: 30" tall tires, 3.73 gear, 4L80E trans with lockup torque converter, Twin Turbocharged Buick 350, Multi Port Fuel Injection run off a megaquirt, also timing and trans controlled by the megasquirt. This combo should do OK for fuel mileage and make a ton of torque between 2500 and 3500 RPM which is the perfect cruising RPM in most cases. I think that 18-20 MPG would not be too unlikely on the highway.
The gear vendors for the 700r4 is for the off road guys who want to run super low gearing on the rocks but still be able to drive 50mph on the roads to and from the trails.
I love my 2.56 gears. And the RPMs are not too low - I feel like I could benefit further with an OD. I only get about 17-18 MPG, but that's also because I have a fairly hi-po cam which is optimized for nitrous and not MPG. -Bob C.
I love my 2.56 gears. And the RPMs are not too low - I feel like I could benefit further with an OD. I only get about 17-18 MPG, but that's also because I have a fairly hi-po cam which is optimized for nitrous and not MPG. -Bob C.
If I had the torque of a 455, I would love 2:56's as well.:bglasses: I've played around with the idea of going with the turbo 3.8, but I'm wondering if the lightweight 215 might have more torque with the same turbo? Has anyone ever turbo-ed a 215? Unless I find a rear with hi-way gears (or just the gears), I guess I'll be looking for a overdrive.
when BigRed was bone stock (94,000 mile 400cu motor, th400, 2.93 open rear) I routinely got 18-19+ mpg on the open highway. Best I ever got on a lowww mile 69 350-2/th350 Sky with 3.23 gears was 15+ Larry aka "The Wiz" put a gearvendors in his 70 stage1 and 3.73's and didn't see much increase over 1-2 mpg if I remember correctly. I think with any cam past something like the 212 towing cam, you really cant have performance and extreme gas mileage It would be interesting to see what a GV could do with a stock BB motor and 3.42's
