I'm looking to see what mpg increase people are getting with the 4T60 (TH440) in the real world. I am interested in knowing:
1. What gear ratio 4T60 (2.84, 3.06 or 3.33) are you running?
2. What motor are you running with it?
3. Are you running a 7730 ECM?
I guess another helpful piece would be what mpg were you getting with your TH125.

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-Brian

My 87 GT Poly Suspension Upgrade (all pics) thread
Removing the roof panel
My HUD install thread
Modified stock air canister and base to 3.5 inch for 3800na

Isn't it strange that after a bombing, everyone blames the bomber, his upbringing, his environment, his culture, his mental state but … after a shooting, the problem is the gun?

Going to link some threads here.

quote Originally posted by MulletproofMonk: I'm looking to see what mpg increase people are getting with the 4T60 (TH440) in the real world. I am interested in knowing: 1. What gear ratio 4T60 (2.84, 3.06 or 3.33) are you running? 2. What motor are you running with it? 3. Are you running a 7730 ECM? I guess another helpful piece would be what mpg were you getting with your TH125.

I find the search program Cliff has can be very finicky and have better luck asking on Google and it will find threads here about things like this sometimes better than our search here on the forum. Sorry Cliff but it doesn't allow for words spelt wrong, or other things that are common mistakes for old folks like me anyway.

http://en.wikipedia.org/wik..._4T60-E_transmission

here is one I found in the forum archives with the Google search,

https://www.fiero.nl/forum/A...060811-2-071061.html

Hope that helped some anyway.

Steve

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Technology is great when it works,
and one big pain in the ass when it doesn't



Detroit iron rules all the rest are just toys.

Thanks, I have searched both ways. Sometimes there is good information and other times it's vague like 30+ or 40+. Does 30+ mean 31mpg or 39mpg? That makes a big difference with a 10 gallon tank...

Also the 4T60E requires either a stand alone transmission controller or mated to an engine that can control it (the 7730 ecm can't). I'm trying to figure my best option for getting more mpg's from a stock 2.8L... I know I can do a motor swap, but I'm not looking to talk about that in this thread.

Contact Forum members MadMark and CapitolCityFieros. They should be able to give you good information.

My wife had Joe put the 4T60 into her 88 notchie. She gets about 34 mpg on the highway with the stock 2.8 and this transmission. Before this swap she had a 2.5 with the 3 speed auto on it and it didn't get that good of mileage and it was a dog. Now with the 4 gears she gets out of the hole better than a stock 3 speed auto and has the better mpg's. At 70 she is turning about 2000 rpm, so I would assume it is around a 2.93:1 gear ratio. Everything else is stock.

[This message has been edited by MadMark (edited 05-12-2014).]

I had a 4.3 CPI/4T60 88 Fiero coupe. I am pretty sure it was the 3.33 ratio final drive as the overall cruise RPM was similar to the Isuzu. It would pull down 32-33 mpg at 70 mph.

My 2.8/Isuzu would also pull down 32-33 mpg on the interstate.

With the 2.8 and the goal being fuel economy, I would go with the middle of the road final drive. It will lower the cruise RPM vs. the isuzu, but still have plenty of RPM so the 2.8 can push it. If you had a larger engine with more low RPM torque, then you could go with the numerically lowest gear set.