[2003 CRV] Underdrives via K20Z1 Pulley
#1
[2003 CRV] Underdrives via K20Z1 Pulley
Gas mileage is abysmal and I have a big fat battery. I've read opinions on the cheap aftermarket U/D pulleys damaging the crankshaft on K24 engines. Saw a post about using stock RSX Type S pulleys since they have a dampener. He had been riding on the A3 pulley in his element with no issue and getting some improvements for at least a year.
Original pulley:
Part #: 13810-RRA-A02
Found in:
2002-2006 Base RSX (k20a3)
2002-2005 Civic Si (k20a3)
2004-2008 TSX (k24a2)
2002-2006 CR-V (k24a1)
2003-2005 Accord (k24a4)
Diameter: 6.125"
Z1 Pulley
Part#: 13810-PRC-003
Found in: 2005-2006 RSX Type-S (k20z1)
Diameter: 5.40"
A2
Diameter: 5.80"
The Z3 is pretty close too.
Diameter: 5.75"
So to according to this I would need:
Honda Pulley tool - $20-30
K20z1 Pulley - new its $130 but I'm sure having all winter to look I could find one cheaper.
New Serpentine belt ????
That's kind of where I fall off. How can I find a compatible belt. The users of this idea never provided a part number or length.
All in all I hope to gain some HP but mainly a few MPG. In the summer I would get 23-25, when my drive shaft was out even 27. But now 21 is the best I get even driving under 60 on the freeway. Advice or help would be appreciated.
Original pulley:
Part #: 13810-RRA-A02
Found in:
2002-2006 Base RSX (k20a3)
2002-2005 Civic Si (k20a3)
2004-2008 TSX (k24a2)
2002-2006 CR-V (k24a1)
2003-2005 Accord (k24a4)
Diameter: 6.125"
Z1 Pulley
Part#: 13810-PRC-003
Found in: 2005-2006 RSX Type-S (k20z1)
Diameter: 5.40"
A2
Diameter: 5.80"
The Z3 is pretty close too.
Diameter: 5.75"
So to according to this I would need:
Honda Pulley tool - $20-30
K20z1 Pulley - new its $130 but I'm sure having all winter to look I could find one cheaper.
New Serpentine belt ????
That's kind of where I fall off. How can I find a compatible belt. The users of this idea never provided a part number or length.
All in all I hope to gain some HP but mainly a few MPG. In the summer I would get 23-25, when my drive shaft was out even 27. But now 21 is the best I get even driving under 60 on the freeway. Advice or help would be appreciated.
#2
-Intl Steve Krew
Re: [2003 CRV] Underdrives via K20Z1 Pulley
What other mods have you done to lessen the MPG?
I don't think UD pulleys will bring up your MPG, not enough to be noticeable....
I don't think UD pulleys will bring up your MPG, not enough to be noticeable....
#3
Re: [2003 CRV] Underdrives via K20Z1 Pulley
I upped the tires to 32psi, changed the oil to 0w20, made sure the maintenance was up. Short of ECU reprogramming what other kind of mods could I do? I can make it 2wd again, seems like a bad idea in the winter.
I was going to start logging o2s and fuel trim on drives this week just to 100% rule out anything being wrong. I already log every trip via OBD.
I was going to start logging o2s and fuel trim on drives this week just to 100% rule out anything being wrong. I already log every trip via OBD.
#4
-Intl Steve Krew
Re: [2003 CRV] Underdrives via K20Z1 Pulley
Honestly you're inline with what the MPG rating is...only way you can change it is to start to remove things like roof racks, and drive slower...
#5
Re: [2003 CRV] Underdrives via K20Z1 Pulley
V8 where I installed a U/D, only the crankshaft, gave 2mpg more, other people had same experience w/ B series hondas and china underdrives... but those don't have a balancer. The pully is old an rusty sucker, there is some wobble there. I already have a new water pump and tensioner pulley. A/C didn't wobble when the belt was off.
I have no roof rack, I already drive slow.
I have no roof rack, I already drive slow.
#6
Re: [2003 CRV] Underdrives via K20Z1 Pulley
I did some investigation on the belts looking at the dayco site.
Standard:
Top Width (in) 0.96
Thickness 0.17
No. of Ribs 7
Different:
2003 Acura RSX S 5070675 lenght: 67.52"
2003 Acura RSX 5070680 lenght: 68
2005 Acura RSX 5070680 lenght: 68"
2005 Acura RSX S 5070670 length: 67.01"
2003 CRV 5070683 lenght: 68.25"
Stock Circumference: 19.24226"
05 RSX S Circumference: 16.9646"
2.27766 /2 = 1.13883
1/2 the difference of pulley circumference is 67.11117
?? 2003 Acura RSX S 5070675 length: 67.52" would be the belt?
Standard:
Top Width (in) 0.96
Thickness 0.17
No. of Ribs 7
Different:
2003 Acura RSX S 5070675 lenght: 67.52"
2003 Acura RSX 5070680 lenght: 68
2005 Acura RSX 5070680 lenght: 68"
2005 Acura RSX S 5070670 length: 67.01"
2003 CRV 5070683 lenght: 68.25"
Stock Circumference: 19.24226"
05 RSX S Circumference: 16.9646"
2.27766 /2 = 1.13883
1/2 the difference of pulley circumference is 67.11117
?? 2003 Acura RSX S 5070675 length: 67.52" would be the belt?
#7
Re: [2003 CRV] Underdrives via K20Z1 Pulley
So just to update: I finally got the pulley installed. The RSX-S 2003 belt fit perfectly. On the K-series you can remove the crank bolt with the starter unlike other Honda engines. I tried the jack method and 2 breaker bars and it wouldn't budge. It's been on there for like 18 years. 1 blip of the starter took it right off. I think I got it back on to the correct torque, my wrench tops out at 160 but I gave it some breaker bar. So far everything seems normal. No unusual stats in torque, no noises, etc. A few weeks worth of driving with the mileage logger will tell if the effort and $70 was worth it.
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#8
Re: [2003 CRV] Underdrives via K20Z1 Pulley
From testing the pulley gives 3-5mpg bonus. I've seen over 30 on the highway for the first time. 32 was the highest so far. So I think this winter I'll be getting summer mileage.
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03-03-2010 08:24 AM