Pulley?'s

[k24ManSam]

Has anyone installed lightweight pulley's? If so how hard was it? Also, what is the benefit to underdriving the crank pulley and overdriving the alternator pulley? Is there really good hp gains from this mod?

 

[squiggy]

I am curious about this, too.

 

[webby]

clutch companies have said you cannot use a lightweight flywheel because it throws the ecu into limp mode. The only way around this is by using hondata flashpro. I don't know if a pulley swap would be enough to cause that same issue or not.

The 2012 and up cars uses a very sensitive crank speed detection system. If the ecu does not see the crank speed up and slow down properly (within what it knows is proper) in between each stage of the 4 stroke cycle (suck, squeeze, bang, blow) it will throw a check engine light and cause the vehicle to go into limp mode.

We have found out that our clutch assembly for the previous gen si's (8037 base kits), when combined with a properly weighted OEM flywheel (22100-RBC-003), will fall within the realm of what the ecu deems as proper and allow the car to run with an aftermarket clutch assembly.

With an aftermarket ecu or perhaps a reflash of the factory ecu you can get around all that and just bolt up a previous gen clutch and flywheel (8037 & 2-800). I hope this clears things up for you.

Thank you,
Dominic F.
Warranty/Tech
Competition Clutch, Inc

when hondata was asked if it could get around the flywheel issue with flashpro-

snip....., and it can switch off the misfire codes associated with light flywheels.
Doug

so hondata has addressed the issue. I do not know what a pulley would do

 

[Nix]

I had NST pulleys on my 8th gen. Install was ridiculously hard only due to the difficulty in removing the stock crank pulley. I since switched to Ralco pulleys. The ralco's were lighter weight but stock size.

The main reason I switched? I can run stock belts from Honda. I got a squeaky one from NAPA and had trouble getting a replacement online or from a store, then when it showed up it had a small nick/tear in it.

I will say it drove a bit better, revved quicker with the NST set, but I am quite happy with the Ralco setup. Second install was a bit easier but still a wicked pain to re-do.

I noticed more pickup and better throttle response. The butt-dyno also noted improvements. Less hesitation taking off from a stop, both slow and quick starts felt better. Overall very decent. I also had an improvement in mileage by about 1.5-2mpg per tank. Slight but there.

I don't know if either company has a 9th gen set out. I would recommend either. Lots of people ran NST, and are still running them thousands of miles later with no issues. I certainly enjoyed mine.

EDIT: Yes there are dyno proven HP gains from this. 5-ish range.

 

[k24ManSam]

So what about the underdriving the crank pulley and overdriving the alternator pulley? Obviously, the alternator would make more juice due to it spinning faster but I am curious what underdriving the crank pulley accomplishes.

 

[squiggy]

The NonStopTuning Honda Civic Si Pulley Kit increases horsepower via great weight reduction and the underdriving of accessories. Superior to other available kits, the NST kit offers an Overdrive Alternator Pulley to optimize output for stereo system lovers!

Each kit is carefully crafted from 6061-T6 aircraft aluminum, tested and balanced to high tolerances. Every NST pulley is hard anodized for exceptional durability and is available in a choice of colors: Red or Graphite Gray.

BENEFITS WEIGHT COMPARISONSOEM NST
Great weight reduction- Average of 65% - 70% over OEM Crank Pulley66oz 13oz
Increased horsepower- Average of 6 - 9 horsepower Alternator Pulley 10oz03oz
Lower ET's & higher trap speeds- Average of .20s & average of 2MPH

http://www.nonstoptuning.com/NSTPULLEYS/pKitHonCivSi.htm

 

[k24ManSam]

The NST pulleys is what spurred my questions. It doesn't state on their website what the advantage of underdriving the crank pulley does though.

 

[squiggy]

The NST pulleys is what spurred my questions. It doesn't state on their website what the advantage of underdriving the crank pulley does though.

I just put that up in response to Nix stating he didn't know if they were available for the 9th gen yet.

Otherwise, I am curious about the under-drive myself.

Just noticed the previous post did not keep proper spacing for weight comparison. Sorry about that everyone.

 

[Nix]

The underdrive crank pulley slows down the accessories a little bit so more power can be sent to the wheels instead. A/C, power steering, water pump.

Pulleys are a good choice for N/A or Turbo applications but not S/C. The power of the S/C depends on the speed of the crank so underdriving that is not a good idea.

If you are uncomfortable with the idea of changing the speeds (over/underdrive) you can always wait until lighter stock size kits are available. Dropping rotating mass will not "add" power but will "free up" power that is already there.

 

[squiggy]

Dropping rotating mass will not "add" power but will "free up" power that is already there.

I assume it essentially lessens the gap between HP that is lost between the crank and wheels?

 

[Nix]

Yes. It is easier to spin a lighter pulley than a heavy one. The difference can be felt immediately in how quickly the car will rev up.

 

[RR'12SiCp]

So are these pullies worth it? Do they jeopardize the reliability of the Honda K24 motor?

 

[Nix]

Quite honestly I could not say. Although @VitViper has said they had no gains at the track from them so in his opinion they are not worth it. I liked mine when I had them but I've since put the car back to stock and never re-installed them.

 

[RR'12SiCp]

Thanks for the quick reply

 

[VitViper]

So are these pullies worth it? Do they jeopardize the reliability of the Honda K24 motor?

You know, the pulley makers will argue til they turn blue in the face that there is no harm from running one of their lightweight crank pullies, and sure, on a bolt on car that barely makes more power than stock, you'll probably last 100k miles.

Hell I used to think the same til I got more and more into motor building and high HP cars.

BUT, the stock pulley IS a harmonic dampener. On an F/I car I would never run a dampener that isn't at least the stock one. I've seen what the damage oil pumps and bearings suffer from not running a proper harmonic dampener.

 

[RR'12SiCp]

Thanks Vit. I appreciate your feedback.

 

[ANtonio mantilla]

http://www.civicx.com/threads/fact-...k-series-k24z7-civic-si-pulley-fb6-fg4.16917/