power question

[okietheranger]

hello everyone! i have a 86 ranger 4x4 with 33" tires with a 89 mustang rebuild 302HO with e cam, and i recently put a zf5 behind it (before was a np435) and i made the 205 heavy ass transfer case work behind the zf5, so with that set up im pretty sure the 8.8 rear end i have has 373 gears, so with that being said i sure have a hell of a time keeping it in overdrive on the freeway, even flat ground with a heavy wind i have to down shift into 4th! this just relaly sucks cause i feel like a have a 2.9L again.. anyone else feel like they dont have enough power for overdrive or is it just me?

 

[RangerSVT]

Double check your gears in the axle, it sounds like you have 2.73's, not 3.73's. You should have plenty of power with that setup...

SVT

 

[okietheranger]

The rear end came out of a 92 ford explorer with a a4ld the tag is gone so I'm not exactly sure what the rear end has. It's about at 2k rpm in overdrive

 

[RangerSVT]

At what speed is it at 2k? With the speed, rpm, tire size and trans gear ratio (3rd gear in the A4LD/4th gear in the ZF is 1:1) the axle gears can be calculated. At 60mph, record your rpm and multiple that by your tire size. Divide that by 20,160 and that will be your axle ratio. For example, your rpm at 60 is 2,000, times your tire size of 33" equals 66,000. That divided by 20,160 gives you an axle ratio of 3.27 (rounded off, of course)...

SVT

 

[MPRanger]

My stock 4.0 SOHC with 4.10's runs at around 2600 RPM at 75 MPH.


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[shane96ranger]

Make a mark on the yoke of the differential, and make a mark on the tire and fender (as a reference point). Then safely secure the front end and put it in neutral, then pick it up so both wheels are off the ground. Have a friend help and turn the the wheel exactly one turn and count how may times the mark on the yoke goes around. 3 1/4 turns means 3.27, 3 1/2 turns means 3.55, 3 3/4 turns is 3.73, 4 turns is a 4.10..... you get the picture. And like Rick's figures, those are also rounded off.

 

[okietheranger]

At 2k I'm doing about 69

 

[okietheranger]

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I found the tag and put it back on. Maybe it has 338 gears?

 

[RangerSVT]

3L7388 means you have 3.73 limited slip 8.8, providing they havent been changed...

SVT

 

[okietheranger]

Ok well that's what I though. Nothing has been changed. Well maybe the motor is having some issues. Weird it runs great I just also thought it was a little underpowered. Like it's really lacking on topend

 

[dangerranger83]

You're just above 200hp and the gen1 rangers are boxes going down the road, didn't take much to feel like you're not going fast.

I'm feel the same way in mine, 200hp, 3.73 gears, 32s and I have an np435 (4th is 1:1) but I'm carbed. The gen1 trucks just aren't aerodynamic so you are pushing a wall of wind.

Question is, where does your setup make the most power in its rpm range? Finding that out will tell you what gears you may need to be running. I'm told those engines really open up after 3k rpm

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[okietheranger]

Well my speedo works so I know it don't feel fast but I'm just trying to go 5mph over speed limit. I had the np435 in before I put this zf in. And on the highway doing 70 with the np435 was around 3k and had plenty of power I'm assuming because more power at the higher rpm. Pretty much after 3 k it's ok on power but nothing impressive at all. I just figured with a rebuilt engine and heads and e cam headers it would at least be cruzing on the highway insted I have to have it almost full throttle

 

[don4331]

You have the 'classic' combination for good fuel economy - engine barely ticking over - 1,600 rpm @ 55mph? and throttle almost wide open. Are you getting decent mileage?

You have too much cam to make power at 'cruising' speed. Stock Explorer doesn't make torque peak until 3,500rpm, "e" cam is significantly hotter, so you have less power than a 3.0. You're engine probably needs to be turning 4k to wake up, and pull hard from there to 5.5k. Unfortunately, your heads even with headers don't allow high rpms.

 

[okietheranger]

Sounds about right. I'm not excatly sure about milage yet. Havnt drivin it ebought to see what it gets. I know with the np435 I was getting around 10mpg. I know the heads suck. Next step I'm gonna do was get a set of afr heads see if that will perk the pony up. I'll try to drive it some more to get a mpg

 

[RangerSVT]

You need a good rv cam that'll give you low to mid range torque, not hot cams that hive you power in the top end. Remember, you want a low rpm torque monster, not a high rpm race engine...

SVT