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Discussion Starter #1
I'm looking at getting some aftermarket cams for my k24a2. Something like Brian Crower Stage 2's, Blueprint Stage 2's etc.

My question:

Should I bother replacing the VTC gear to the 50 degree one from the RSX?

I know with some cams it's not safe to use the full 50 degrees anyway so is the 25 degree VTC gear really that bad? I'm thinking the 25 degree mechanical limit could be a good safeguard with aftermarket cams.

Opinions? Advice?

Cheers,
Chris
 

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its also a known fact vtc can spike above the settings in K-pro. You'd be better off claying the motor (or buying cams with a known limit with the k24a2) to determine max vtc & then machining the tsx gear to match the limit
 

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Discussion Starter #4
If you want to maximise your gains through the power band on stock pistons then I recommend buying a cam that will not have clearance issues at 50 vtc.
Thanks for the advice. I know some IPS cams can work with the full 50 degrees on a k20a2, but how about k24a2? Isn't the piston to valve clearance less on the k24a2? Hondata only reccomends 45degrees with the standard cams so with aftermarket cams I'd assume it'd be even less than that.

Btw, this is for a daily driven car so I don't mind if I miss out on a few HP by staying with the 25 degree VTC. I just want to make sure that I'm not missing out on 10+whp if I don't change out the VTC gear.

its also a known fact vtc can spike above the settings in K-pro. You'd be better off claying the motor (or buying cams with a known limit with the k24a2) to determine max vtc & then machining the tsx gear to match the limit
That's what I'm worried about. Reliability is more important to me than a few extra HP so I'd rather keep the VTC a few degrees under the limit of the cams.

I just don't want to shoot myself in the foot power wise by staying with the 25 degree VTC. If it's only a matter of a few HP, I can live with that.

so what's the verdict guys?
 

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Thanks for the advice. I know some IPS cams can work with the full 50 degrees on a k20a2, but how about k24a2? Isn't the piston to valve clearance less on the k24a2? Hondata only reccomends 45degrees with the standard cams so with aftermarket cams I'd assume it'd be even less than that.

Btw, this is for a daily driven car so I don't mind if I miss out on a few HP by staying with the 25 degree VTC. I just want to make sure that I'm not missing out on 10+whp if I don't change out the VTC gear.



That's what I'm worried about. Reliability is more important to me than a few extra HP so I'd rather keep the VTC a few degrees under the limit of the cams.

I just don't want to shoot myself in the foot power wise by staying with the 25 degree VTC. If it's only a matter of a few HP, I can live with that.

so what's the verdict guys?
K2's (original or MkII) will work (full 50*) on a stock K24A2. Not sure about the KME's, but I would not go that aggressive unless you are raising the compression. Being that it is a daily driver I recommend the K2's, they are reliable, and offer the broadest powerband.
What other mods do you have?
RBC and good header/exhaust and you are set.
 

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Thanks for the advice. I know some IPS cams can work with the full 50 degrees on a k20a2, but how about k24a2? Isn't the piston to valve clearance less on the k24a2? Hondata only reccomends 45degrees with the standard cams so with aftermarket cams I'd assume it'd be even less than that.

Btw, this is for a daily driven car so I don't mind if I miss out on a few HP by staying with the 25 degree VTC. I just want to make sure that I'm not missing out on 10+whp if I don't change out the VTC gear.



That's what I'm worried about. Reliability is more important to me than a few extra HP so I'd rather keep the VTC a few degrees under the limit of the cams.

I just don't want to shoot myself in the foot power wise by staying with the 25 degree VTC. If it's only a matter of a few HP, I can live with that.

so what's the verdict guys?
you'll be leaving a lot of midrange HP on the table if you limit yourself to 25deg advance with most stage II type aftermarket cams.

As mentioned before, the best option would be for you to clay your motor, find your VTC limit, and limit yourself to that via a modded gear.

You can rely on k-pro to limit VTC, but it's not ideal. With my stage II cams I couldn't go a full 50deg on my build, but I limited the advance to 45 in k-pro and never had any issues. There are some special rules that apply when you run an a3 head, but with an a2 head, the software regulates VTC just fine.

Note that you still need to clay your head to know what your VTC limit is even if you elect to limit it via software.
 

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you'll be leaving a lot of midrange HP on the table if you limit yourself to 25deg advance with most stage II type aftermarket cams.

As mentioned before, the best option would be for you to clay your motor, find your VTC limit, and limit yourself to that via a modded gear.

You can rely on k-pro to limit VTC, but it's not ideal. With my stage II cams I couldn't go a full 50deg on my build, but I limited the advance to 45 in k-pro and never had any issues. There are some special rules that apply when you run an a3 head, but with an a2 head, the software regulates VTC just fine.

Note that you still need to clay your head to know what your VTC limit is even if you elect to limit it via software.
Why is that? I have looked for something from Hondata explaining it before, never found anything. Just saw the spikes on datalogs.
 

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Discussion Starter #8
K2's (original or MkII) will work (full 50*) on a stock K24A2. Not sure about the KME's, but I would not go that aggressive unless you are raising the compression. Being that it is a daily driver I recommend the K2's, they are reliable, and offer the broadest powerband.
What other mods do you have?
RBC and good header/exhaust and you are set.
Ok thanks, I'll look into the IPS k2's a bit more. Unless I can find a second hand set they'll be out of my budget though.

I have the standard PRB and standard throttle body.

Mods are:
gruppeM intake
maxim works header (no super long primaries but it's a quality piece)

2.5" straight through exhaust (i know 3" is better but I won't be changing it)

my car
 

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Discussion Starter #10
you'll be leaving a lot of midrange HP on the table if you limit yourself to 25deg advance with most stage II type aftermarket cams.

As mentioned before, the best option would be for you to clay your motor, find your VTC limit, and limit yourself to that via a modded gear.

You can rely on k-pro to limit VTC, but it's not ideal. With my stage II cams I couldn't go a full 50deg on my build, but I limited the advance to 45 in k-pro and never had any issues. There are some special rules that apply when you run an a3 head, but with an a2 head, the software regulates VTC just fine.

Note that you still need to clay your head to know what your VTC limit is even if you elect to limit it via software.
Thanks for the information. I don't trust any local shops to correctly modify/machine the VTC. So I'd be buying if an RSX 50 degree VTC and using the ECU to limit the advance if I went down that path.

Very Nice! :up:
Looks great. Do you have K-pro or something to tune with?
Cheers :).

I'm based in Australia so I'm going with the locally made Vi-Pec V88 ECU, just waiting for the drive-by-wire firmware update to be released (http://www.vi-pec.com/). I'll be getting the cams installed as soon as the ECU goes in.
 

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Discussion Starter #12
Thanks for the link, I have read about pec in the past, I will look at the site when I am home.
What year is the car?
There are no local workshops that I trust that deal with Kpro so the dual ECU k-pro ecu is out for me (also seems expensive for what it is).

The Vi-pec definitely looks good on paper, lots of advanced functions.
The price is actually pretty reasonable too when compared to some other drive-by-wire compatible ECU's out there.
 
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