[zonker]

I've been trying to come up with a way to underdrive the accessory pulleys on my 1991 2.3.

I purchased a Esslinger UDP to fit one onto my car and found out after I removed the stock pulley that it will not work on a 91-93 dual plug 2.3.
It's a shame too, since the esslinger pulley is a beautiful piece that would have given me a 32 percent
underdrive across the board.

So... if you have a 2.3 with a distributor like the 87-90 2.3 Mustangs and 87-88 T-Bird Turbos, go with the $90 Esslinger pulley.

But, if you have no distributor like me, then here's your current best option:

Here's what I now have on my car:
1992 Ford Ranger 2.3 Double Belt Crank Pulley
1988 Ford T-Bird Turbo 2.3t Water Pump Pulley
1994 Ford Explorer 3.0 V6 Alternator pulley
537k6 Alternator Serpentine Belt
427k6 A/C Compressor Serpentine Belt

Here's how much it's has underdriven the accessories:
Alternator - 31%
Power Steering - 14%
Water Pump - 14%
Air Cond - 5%

OLD BELT ROUTING
1. Alternator, Water Pump, Power Steering, Crankshaft
2. Water Pump, A/C Compressor, Crankshaft

NEW BELT ROUTING:
1. Alternator, Water Pump, Power Steering (not on crank anymore)
2. Water Pump, A/C Compressor, Crankshaft



ORIGINAL PULLEY SPECS - 1991 Dual Plug 2.3:
Crank - dual belt - 6.1875" and 4.9375"
W/P (p/n F1ZE-8509-AA) - dual belt - 5.3125" and 4.3125"
Alternator - 2.5625"

NEW PULLEY SPECS:
Ranger Crank Pulley - dual belt, 6.1875" and 4.6875" diameters
(IMPORTANT NOTE: you only put a belt on the 4.6875" pulley, the 6.1875" pulley is left blank)
T-Bird WP pulley (p/n E7SE-8509-AA) - dual belt, 5.875" and 4.75" diameters
Explorer Alt Pulley - 2.875"

RESULTS:
The car does rev a little easier, and there is a small seat of the pants improvement. I should even see a small mpg improvement as well since it will require less effort to turn all those pulleys.

CONCLUSION:
A worthwhile mod for the cost of 3 used junkyard pulleys and a new serpentine belt.

FUTURE PLANS:
I still hope to have Esslinger make us a water pump pulley that will further underdrive the water pump,
alternator, and ps pump by using a billet 5.875" / 5.875" dual belt pulley, but for now this is the best I can come up with.

[TaterTodd]

wow, dude you put some thought into that ... would have liked to see some dyno pulls of the before and after ... I'm curious as to how much of a difference it makes. Good going!

[zonker]

Originally Posted by TaterTodd wow, dude you put some thought into that ... would have liked to see some dyno pulls of the before and after ... I'm curious as to how much of a difference it makes. Good going!

thanks - it was my obsession this last week to get it figured out...
As for how much power, since its a seat of the pants feel, my butt dyno puts it in the 4-5hp range. On zetecs a 25% underdrive ratio gives 6-8hp on the dyno, and anything less than a 4-5 hp bump is not discernable to the 'ol butt.

to give you an idea of how that affects the accessory rpms, compare the following:

Stock 1991 2.3 (1000, 2500, 5000 engine rpm):
crank - 1000, 2500, 5000 rpm
water pump - 1164, 2910, 5820 rpm
power steering - 1062, 2656, 5310 rpm
alternator - 2750, 6875, 13750 rpm

Modified Pulleys
crank - 1000, 2500, 5000 rpm
water pump - 996, 2490, 4980 rpm
power steering - 1005, 2512, 5025 rpm
alternator - 1875, 4687, 9375 rpm

One can see how hp is made by how much slower the accesories have to turn.
Also figure they'll last longer too, since they're spinning at a slower speed.

[zonker]

Did another timed run with my Android phone after the pulley change - It has given me 0.2 seconds from 0-30 mph and in the 1/8 mile.

Not bad, it's the most new hp I've gotten so far from my driveway tinkering.

[thedriver33]

Not a bad upgrade.....just finished mine, im not running a/c so i left stock crank pulley, 2.3t w/p pulley, 94-98 v6 ps pulley........not doing the alt pulley cuz i plan to do a 3g upgrade for mine here in a bit.

But with that pulley upgraded and ranger header, blocked egr......and modded air box, this car is starting to move better.

[zonker]

If you don't run ac but the car still has the tensioner for the AC then you can run the ranger crank pulley and run crank-waterpump-tensioner on the outside and waterpump-powersteer-alternator-tensioner on the inside. That will give you another 5% underdrive on the w/p, alt, and PS.

[thedriver33]

...i couldnt find any 2.3 rangers in the yard......only found 2 bodys that had nothing....but i was amazed to find that turbo coupe with everything there on it....going back next week to get some more stuff off it, and see if cant get a ranger pulley.

may grab the turbo manifold, injectors, valve cover.........the turbo was beat......shaft play was huge....

[87fourbanger]

What?? Sounds interesting but Dnt know what this is about. If any one has ex time to enlighten me w info on what zonker is doing to his car. Thanks

[thedriver33]

he used other stock pulleys from other 2.3s to make a underdrive system from our cars.....i followed his idea and included an addition pulley.....but i still need one more pulley to finish mine.

[zonker]

Originally Posted by 87fourbanger What?? Sounds interesting but Dnt know what this is about. If any one has ex time to enlighten me w info on what zonker is doing to his car. Thanks

How much enlightenment do you need, grasshopper?

Is the whole underdrive concept a mystery?

Underdrive Pulleys = Power Pulleys (another word used for them)

It's all about making the engine work less hard to turn the accessories (water pump, air cond compressor, power steering pump, alternator). This is accomplished by changing the diameters of the pulleys in order to slow the rpms of the engine accessory(s).

Clearer?

[blaten22]

May sound a bit stretched but food for thought. Wonder if you could get or makeshift an Electric water pump?.

[zonker]

that would be a way to reduce some of the parasitic losses as well, and they are nice in the sense that you can have a constant flow rate, but i think some of the gains you see are eaten up by additional hp load on the alternator.

also there's a long term quality issue to deal with too. Meziere for example says the pump motors are used up at 75k miles.

it might not be worth the investment imo

[87fourbanger]

So u get bigger diameter pulleys?

[zonker]

Originally Posted by 87fourbanger So u get bigger diameter pulleys?

yes, and no...

drive pulleys need to be smaller and driven pulleys needs to be larger

[87fourbanger]

Ok.. I'm trying to get it. Drive pulleys and driven? What's the diff

[PunkRockGearhead88]

Im curious, if your car is an auto, how is it charging at a red light in gear with your foot on the brake and the A/C on?

[thedriver33]

the crank is the only drive pulley......all the others are driven by the crank....

[zonker]

Originally Posted by PunkRockGearhead88 Im curious, if your car is an auto, how is it charging at a red light in gear with your foot on the brake and the A/C on?

At that point it probably isn't charging much since at 750 rpm the alternator is spinning as it would be at 525 rpm, and that still throws a charge, just not a strong one.

The battery can more than handle the low charge to discharge for the brief amount of time one spends at that low an rpm in those conditions. Typically an engine doesn't idle like that for more than 5 minutes without some type of rpm increase.

On my modded ZX2, I run a 40% underdrive pulley at the crank and other than a little dimming of the headlights at idle, all is fine. Now if you have a audio system that requires a 200 am alternator and 80 amp fuses on it, well underdriving isn't for you.

But look at it this way, if you underdrive, your car is now a hybrid!
It is using battery power to offset the low charging output under limited driving conditions. Tell your eco friends you're helping to save the environment by using battery power to keep your engine running at idle which saves gas.

[zonker]

Originally Posted by thedriver33 the crank is the only drive pulley......all the others are driven by the crank....

Ahhh... yes and no.

For example a the oem 87-90 2.3 mustang uses the water pump pulley to turn the a/c compressor, making the water pump pulley the drive pulley for the a/c compressor, which is the driven pulley. The water pump pulley in this case is both a drive and a driven pulley since the second pulley of the water pump is driven by the crank, which is almost always a drive pulley.

Thats the same principle I used on my 1991... except I am driving the alt and power steering from the water pump (drive side) and the crank turns the a/c compressor and the water pump (driven side).

[87fourbanger]

Wow that's cool! So what do you get. Out of this mod?