Last post on Jun 06, 2008 at 10:37 AM
You are in the Speed Shop Tuning and Modification
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GMC Jimmy, Chevrolet Blazer, Fuel System, SUV
Mar 05, 2008 (9:26 pm)
i have an 1986 k5 blazer 4x4 with 3.73 gears, and with the recent raping that we are taking from big oil, i need to do some modifications to get better fuel economy. please help i am willing to try anything the more ideas the better, if someone suggests changing gears i would like to know how high i can go without doing any damage to the drivetrain
#5 of 8 Re: fuel economy [1986blazer]
Mar 07, 2008 (6:26 pm)
do you have an auto or manual trans. 373 with 4 speed auto is not bad. the problem is you have to make front to rear gear changes. the cost minus the assumed savings may justify leaving it alone.
#6 of 8 Re: fuel economy [okko1]
Mar 07, 2008 (7:33 pm)
Do you need a truck? I'd look for a more economical car in terms of gas if you don't absolutely need the truck.
#7 of 8 ignition timimg
May 31, 2008 (5:19 am)
what is the timing for 86 chevrolet 350,ie 2,4,6,8,DEGREES .the sticker is gone on the radiator support that usually tells you. thanks.
#8 of 8 Re: fuel economy [1986blazer]
Jun 06, 2008 (10:37 am)
Changing the gear ratios from 3.73 won't be much help. That is already a very good compromise between economy and effeciency. 3.42 was higher ratio for those years, not sure if it was available on a Blazer though. I had an 85 Suburban with 3.42, it was OK on fuel mileage (well, for a carbureted Suburban anyway), but absolutely was terrible at towing anything other than a light load.
The best modification you can do is to your driving habits. Slow down, try to stay in higher gears, leave it parked more often.