Increasing efficiency, within reason? (long post)

Topic: Increasing efficiency, within reason? (long post) (Read 4079 times) previous topic - next topic

Re: Increasing efficiency, within reason? (long post)

Reply #30 – September 20, 2005, 10:41:15 AM

Quote from: TurboCoupe50

A AOD can be built using the 4R70W gear set... As for swapping in a Electronic tranny, I'd use a 94-95 Mustang automatic EEC that can shift the tranny and operate a electric fan. The fan is something not mentioned that does help fuel economy.

Yeah, I know about the AOD case/4R70W gear set thing. That is also a possibility.

If I go electronic, I was thinking about a Baumannator TCS or whatever the hell it was called. I think one of its stated purposes was to allow for putting electronic trannies into older vehicles.. plus it's programmable.

As for controlling a fan, I had planned to do the modified Mark VIII fan + control box thing that was posted here awhile back. (the one that gradually powers it up and down on demand, vs. just on/off) I'll probably do that no matter what else I do to the car.

Re: Increasing efficiency, within reason? (long post)

Reply #31 – September 20, 2005, 12:09:05 PM

OK, lemme try this:

Doing the 4R70W swap while leaving in the 3.27 rear gears would give me (as that quote above stated) the same effect in 1st gear as if I had 3.87 rear gears plus the AOD.. but the OD would remain pretty much the same (maybe a difference of 100 RPM or so) as it is now. Would that be beneficial from an efficiency standpoint? I see lots of talk about being hard to get the car moving with numerically lower rear gears.. well this *seems* to counteract that. Does it go too far?

Even if it isn't the most effective solution, I still like the thought of using the 4R70W. It's supposed to be upgraded in every necessary way vs. an AOD. Bigger OD band, etc. Yes, I could rebuild an AOD to close to 4R70W levels.. but if I could manage to find a 4R70W that I could use, why not use it?

I've also contemplated a stick.. but if I went that route, honestly I would want to go T56.. and that ain't gonna be cheap either. That debate is a whole other can of worms I won't go into at this time.

Re: Increasing efficiency, within reason? (long post)

Reply #32 – September 20, 2005, 11:45:51 PM

Quote from: slamedcat

My 88 XR7 with its almighty 3.08 and 235/60R15 will run down the interstate at 80 only running 2000rpm.

I wouldn't go with a 2.73 just because it would take so much more to get the car rolling from a stop.

Two questions...are you sure you have 3.08's? if so, did you get a different speedo driven gear or no?

With 2.73's you should be running 80@2000rpm. With 3.08's, you would actually be running more like 71-73mph@2000rpm...if you haven't changed speedo gears, then you are going slower than your speedo reads.

Sidebar: The change from 2.73 to 3.08 was quite noticable in the seat of the pants...can't wait to put in my 3.55's.

Re: Increasing efficiency, within reason? (long post)

Reply #33 – September 21, 2005, 12:03:59 AM

Well, my current mileage is about to be put to the test.. because I start work 7 hours and 57 minutes from the time of this posting. :p

Re: Increasing efficiency, within reason? (long post)

Reply #34 – September 21, 2005, 12:22:28 AM

Well there isn't that much of difference between the 235/60 and 225/60. No I didn't change the speedo gear.

225/60R15 = 25.63
235/60R15 = 26.10

Next the 3.08 was stasndard with the XR7.

78.3mph by my calculations.

equaltion goes like this.
((235/25.4*((60/100)*2+15))*2000)/(3.08*.67+346) = 78.3

close enough to 80 for me.

So 80mph at 2000rpm.

Re: Increasing efficiency, within reason? (long post)

Reply #35 – September 21, 2005, 01:09:05 PM

Quote from: slamedcat

78.3mph by my calculations.

equaltion goes like this.
((235/25.4*((60/100)*2+15))*2000)/(3.08*.67+346) = 78.3

close enough to 80 for me.

So 80mph at 2000rpm.

OD ratio is .68 not .67
:hick:

Re: Increasing efficiency, within reason? (long post)

Reply #36 – September 21, 2005, 03:07:45 PM

http://www.foxtbirdcougarforums.com/showthread.php?t=3772&page=3&pp=40&highlight=.67

Re: Increasing efficiency, within reason? (long post)

Reply #37 – September 21, 2005, 04:02:11 PM

My car.....1988 Thunderbird.

Statistics...1987 5.0 H.O.,Explorer intake,60mm throttlebody,Factory headers (for now),H Pipe,Removed the air silencer,Locker rear with 3.45 gears.I got 26 miles per gallon at nearly 80 at 2000 rpms,without using the cruise control.If I would've used the cruise,probably a little better,if I would've used cruise at 70,then I can only wonder what the MPG woul be.Hmmmmmmmmmmm................

Re: Increasing efficiency, within reason? (long post)

Reply #38 – September 21, 2005, 04:43:04 PM

back to the mythbusters, that was a failed experiment and had no controls, I don't trust it, it is a cool show (and i watch it when I can), but they are by no means scientific in the least most of the time.

but they had 2 different vehicle with two differend drivers and just filled em and ran em till they stopped. not a good test of actual mpg at all. so that one holds no wait with me.

Re: Increasing efficiency, within reason? (long post)

Reply #39 – September 21, 2005, 05:20:34 PM

Quote from: Funky Cricket

back to the mythbusters, that was a failed experiment and had no controls, I don't trust it, it is a cool show (and i watch it when I can), but they are by no means scientific in the least most of the time.

but they had 2 different vehicle with two differend drivers and just filled em and ran em till they stopped. not a good test of actual mpg at all. so that one holds no wait with me.

Uhh... I don't know which show you watched, but that wasn't the experiment at all. They used two identical suvs, I think they were Tahoes or something similar. They pumped all the gas out and put exactly the same amount of gas back into both and drove on a track until one ran out. One with windows open and one with a/c on.

Re: Increasing efficiency, within reason? (long post)

Reply #40 – September 21, 2005, 10:54:45 PM

Okay, good supporting info on the OD ratio. But, you're speed is still a few mph high @2000rpm in OD with the 3.08's. Did you measure the diameter of the tire at the recommended inflation pressure while loaded(i.e.-on the car). Or are you using tire manufacturer's specs...some measure diameter with the tires loaded, others don't. A 10mm width difference equates to a sidewall height difference of 6mm. Six millimeters is not equivalent to .47", so something in your equation isn't happy. Six millimeters is closer to 1/2 of .47". I'm not trying to break balls, but I'd like to know where you got your tire diameters from because you're equation is all in order.

With a 25.6" tire(the 225) according to your specs, you would be going 74mph(rounded up 2 tenths). With a 26.1" tire(the 235), again according to your specs, you'd actually be going 75mph(round down 3 tenths). Unfortunately I can't remember what I measured my old cobra 225's at...I'll measure my 225's and my 265's tomorrow.

This is what I used- http://www.4lo.com/calc/gearratio.htm

Re: Increasing efficiency, within reason? (long post)

Reply #41 – September 21, 2005, 11:32:39 PM

235/60r15

235/25.4*.6*2+15=26.95

225/60r15

225/25.4*.6*2+15=25.63

Heres another to ponder. With the 235/60R16 the 3.08 ratio turns into 3.03

(20800/((235/25.4)*(60/100)*2+15))/(20800/((225/25.4)*(60/100)*2+15))*3.08=3.03
:hick:

Re: Increasing efficiency, within reason? (long post)

Reply #42 – September 22, 2005, 12:45:46 PM

I understand your thinking, but that equation is worthless for figuring tire diameter. I used that formula in the past and it just didn't seem right, the more I looked at it, the more flawed it was. My 225/60's(full tread, 32psi) measured out at 24.5"(within 1/32") while on the car. My 265/50's measured the same within the same accuracy but with 28psi and nearly full tread. Metric tire sizes are always rounded...I'll bet you've never heard of a 221/58R15.

The only accurate way to find the tire diameter is to measure the diameter of the tire while it's on the car(with the wheels on the ground, no cheating). The easiest way is to take a ruler or similar object and lay it across the top of the tire so it extends out toward the wheel well. Take a tape measure and measure from the ground to the bottom side of the ruler or whatever you may be using. That is the ONLY way to get true tire diameters.

Re: Increasing efficiency, within reason? (long post)

Reply #43 – September 22, 2005, 12:53:32 PM

That equation cam from a "Mast Fittment Guide" that was at the shop I worked at. The book is put out by Michilen of North America.

Not to be pissy but try telling them their wrong. :rolleyes:

I also understand what you are saying. But what about cyntrifical force pulling on that tire when its do 80mph. Its not going to have the same dia when its moving.

Re: Increasing efficiency, within reason? (long post)

Reply #44 – September 22, 2005, 01:14:55 PM

OK, somewhat closer to the topic:

Perhaps I should look into getting a nice clean 4-door Fairmont or Zephyr, swapping in some more comfortable seats from one of the bigger Fox bodies, and trying to make that a little more efficient? (and keep the Mark for road trips)

How well, efficiency-wise, would a 2.3T do in something as (relatively) light as a Fairmont? I think it's been said before that the TCs aren't the most efficient of cars, gas-wise.. but is that mainly due to performance of the engine while not under boost? (trying to move a heavier car, etc.)

I see a few Fairmonts/Zephyrs running around town now and again. (including that Fairmont Ranchero I saw awhile back)