acceleration difference between my 91 and 96 EB's

[cmayna]

Recently I bought a 96 EB giving my 91 EB to my son.

I have a 4.0 in both vehicles, yet when I accelerate the 91 is MUCH faster in getting up to 65mph as compared to my 96. It's like day and nite. Whaazzzuuupp with this ?

The 96 runs extremely well, very smooth. Engine idles great.

Is the 96 EB that much heavier which would cause it to be sooo much slower than my 91 ???

 

[SaleenEXP]

Originally posted by cmayna
Recently I bought a 96 EB giving my 91 EB to my son.

I have a 4.0 in both vehicles, yet when I accelerate the 91 is MUCH faster in getting up to 65mph as compared to my 96. It's like day and nite. Whaazzzuuupp with this ?

The 96 runs extremely well, very smooth. Engine idles great.

Is the 96 EB that much heavier which would cause it to be sooo much slower than my 91 ???

what gear ratio do you have in the 91'? If the 91' is quicker you probably have the 3.27 gears in the 96' and the 96' is also a little heavier, but the gears are whats holding the 96' back.

 

[Alec]

Yup, probably due to gear ratio.

Does the 96 run less RPMs on the highway compared to the 91? Does it have more pep on the hwy than the 91?

 

[cmayna]

I don't know the gear ratio on my 96'. Does anyone know what came stock with it ? How can I find out ? What's the old rule ? for every wheel revolution, the driveline would turn for example 3.27 times for a 3.27 gear ratio ?

I bought the vehicle from someone who never modified it so I assume it's very stock. Tonight I'm going to drive both on the highway to compare RPM vs speed and will report back.

If it was found that the gears are different, and I decided to change the gears, what impact on gas mileage would I see. This is asked because I know that I'm getting much better gas mileage on my 91 as compared to the 96.

Thanks

 

[Alec]

There will be an axle code printed on your driver door.

43 Open 3200 3.08
41 Open 3200 3.27
42 Open 4.10
46 Open 3.73
45 Open 3200 3.55
D4 Limited Slip 3200 3.73
D2 Limited Slip 4.10
L73 Limited Slip 3.73

Your 91 could be getting better mileage due to less weight, lack of EGR, and better matching of the gears to the motor. Low revs don't always mean good mileage, the engine has to be running at efficient rpms.

 

[cmayna]

Thanks for the data. Tonight I'll check the markings on the door. I question if anyone knows what is the optimum gear ratio for an engine like my 96 EB has ? I just can't believe how much quicker my 91 is from a dead start as compared to the 96. I wonder if the timing is off or the plugs are dirty.

 

[SaleenEXP]

You most likely have 3.73 or 4.10's in your 91' and I will bet you probably have 3.27's on your 96'. But you should get better mileage in the 96' and have better passing power on the highway than the 91' with either of the gears because it's already spinning higher in the rpms where the ohv sucks. You might just need a tune-up on the 96' if it's getting worse mileage.

 

[Jason_25]

An EB with 3.27's?? That's surprising considering explorers with 16" wheels only came with 3.73's and 4.10's

Your 91 has alot going for it. For one, it does weigh less. Also, I have noticed that both my friend's 91 models have a larger factory exhaust than I do. Also keep in mind that the stricter emissions standards in your 96 might be "robbing" some of it's power.

 

[SaleenEXP]

Originally posted by Jason_25
An EB with 3.27's?? That's surprising considering explorers with 16" wheels only came with 3.73's and 4.10's

Your 91 has alot going for it. For one, it does weigh less. Also, I have noticed that both my friend's 91 models have a larger factory exhaust than I do. Also keep in mind that the stricter emissions standards in your 96 might be "robbing" some of it's power.

Thats what I thought, but a guy at school has a 96' Eddie Bauer with the 3.27 rear axle, don't know how that happened as the truck has never been in an accident or had trans problems, his parents bought it new and gave it to him. Weird....

 

[cmayna]

OK, here's an update. Thanks to Alec's listing of codes on the door I discovered that my 91 EB has 3.73 gears (code D4) and the 96 EB has 4.10 gears (code D2).

Here's some more tidbit of info:

With similar driving during the past 24 hours, my 91 mpg was 18.34 mpg while the 96 was 15.14 mpg.

Also per Alec's previous question:
The 91 rpm for 65 mph is 2,000 whereas the 96 rpm for similar mph is 2,400.

So the way I look at it based upon the engine's RPM is spinning faster on the 96 and since it has a lower rear end gear (4.10) am I right that it make sense that the 96 is getting lousier gas mileage ?

 

[cmayna]

I'm still going to change the wires and plugs to Splitfires and Bosch 4+ just to make sure that I get the most out of the 96.

 

[Alec]

The mileage and rpms make sense with those gears. Doesn't make sense why the 96 is noticalby slower. It should be quicker off the line. Maybe it just needs some TLC. I would not use +4 plugs. Use good (Motorcraft) double platinum plugs. I also use Motorcraft wires. Could also try cleaning the MAS and doing some other minor things.