Underdrive Pullys?
01-05-2005, 08:46 PM
#3
Senior Member
Join Date: Dec 2001
Location: Jensen Beach, FL / Sylva, NC
Posts: 2,934
I just installed some underdrive pullys in my car. I have debated it and keep waffling over it.
Yes, my voltage dropped at idle and low RPMs but it seems to be the same at higher RPM's.
Why did I install the pully's? Because at a very fast Autocross where my car spent 75%+ of its time over 5K RPMs I had some problems with my cooling system.
The problem or I should say argument I am having with myself is that I street drive my car a lot. Probably 95% of the time. So was the pully kit necessary?
It is simple to install and I am toying with just swapping it on when I am going to race an Autocross.
If you are doing it soley for looks or for 2 more RWHP I would save my money.
Yes, my voltage dropped at idle and low RPMs but it seems to be the same at higher RPM's.
Why did I install the pully's? Because at a very fast Autocross where my car spent 75%+ of its time over 5K RPMs I had some problems with my cooling system.
The problem or I should say argument I am having with myself is that I street drive my car a lot. Probably 95% of the time. So was the pully kit necessary?
It is simple to install and I am toying with just swapping it on when I am going to race an Autocross.
If you are doing it soley for looks or for 2 more RWHP I would save my money.
01-05-2005, 08:53 PM
#4
Senior Member
Join Date: Mar 2003
Location: Sunny South Florida :)
Posts: 1,963
i had a mazdaracing kit for my n/a fc, so i could retain p/s and a/c. Everything seemed to work fine. p/s kept up, and a/c was still cold.
there was a small voltage drop at idle, @900 rpm, so i raised it to 1100rpm, and it charged 14v. perfect!
I really like mazdaracing stuff. good quality, but they're aren't populaur enought to sell it for 1000% profit. So it makes it a killer value. On a stock n/a they have dyno charts showing before and after. It was like 10 hp, and 8 ft/lbs. In a turbo car, it's not night and day, but in a n/a every little bit counts!
there was a small voltage drop at idle, @900 rpm, so i raised it to 1100rpm, and it charged 14v. perfect!
I really like mazdaracing stuff. good quality, but they're aren't populaur enought to sell it for 1000% profit. So it makes it a killer value. On a stock n/a they have dyno charts showing before and after. It was like 10 hp, and 8 ft/lbs. In a turbo car, it's not night and day, but in a n/a every little bit counts!
01-07-2005, 05:46 AM
#5
Senior Member
Join Date: Mar 2003
Location: Florida
Posts: 127
Yeah, the Mazdaracing stuff is top notch (good CAD designs)
TII street car, I wouldn't waste the time.
N/A hell yeah! Street/ race, doesn't matter.
Jim, I believe what's happening with yours is @ high RPM's, the water pump is not so much pumping as it is churning the water. In that case, I agree, got to under drive that bitch!
We need a kit that under drives the water pump but over drives the alt.
TII street car, I wouldn't waste the time.
N/A hell yeah! Street/ race, doesn't matter.
Jim, I believe what's happening with yours is @ high RPM's, the water pump is not so much pumping as it is churning the water. In that case, I agree, got to under drive that bitch!
We need a kit that under drives the water pump but over drives the alt.
05-05-2005, 11:03 AM
#9
Senior Member
Join Date: Sep 2003
Location: Canyon Country, CALIFORNIA
Posts: 123
[quote name='banzaitoyota' date='May 5 2005, 06:37 AM']Rez, I would install shorter belts to give you your adjustment back
[/quote]
Yeah, as I figured. I ended up maxing out the air pump after doing some cutting on the bracket to give me that extra 1/4 inch length to get the belt fully tight.
I also used a spare air pump belt for the AC compressor. The tension pully was maxxed out.
As for the power steering, it's somewhere between the size of the A/C belt and PS belt.
The alternator belt seems to work fine, however, it also is near max tension room on the bracket.
I just thought I'd share for anyone considering this setup.
[snapback]708587[/snapback]
[/quote]
Yeah, as I figured. I ended up maxing out the air pump after doing some cutting on the bracket to give me that extra 1/4 inch length to get the belt fully tight.
I also used a spare air pump belt for the AC compressor. The tension pully was maxxed out.
As for the power steering, it's somewhere between the size of the A/C belt and PS belt.
The alternator belt seems to work fine, however, it also is near max tension room on the bracket.
I just thought I'd share for anyone considering this setup.
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