Is it true K-series dont really need adjustable cam gears?
11-21-2003, 10:40 PM
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Re: Is it true K-series dont really need adjustable cam gears? (electric_)
Yes, I believe it's true because Honda has incorporated them into the cam design, it's where the "i" in i-VTEC comes from, because the computer will automatically adjust the cams.
11-22-2003, 12:43 AM
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Re: Is it true K-series dont really need adjustable cam gears? (electric_)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by electric_ »</TD></TR><TR><TD CLASS="quote">Is it true K-series dont really need adjustable cam gears?</TD></TR></TABLE>
YES, that is right....
YES, that is right....
11-22-2003, 12:11 PM
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Re: Is it true K-series dont really need adjustable cam gears? (vtecvoodoo)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtecvoodoo »</TD></TR><TR><TD CLASS="quote">I believe they can adjust themselves up to 25 degrees in each direction.</TD></TR></TABLE>correct
11-22-2003, 12:25 PM
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Re: Is it true K-series dont really need adjustable cam gears? (sleeprhatch)
i bet aftermarket companies dont like that....thats a whole market they lost out on.
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11-22-2003, 01:10 PM
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Re: Is it true K-series dont really need adjustable cam gears? (Bob-DC2)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bob-DC2 »</TD></TR><TR><TD CLASS="quote">can u you change the way the computer changes the timing of the cams?</TD></TR></TABLE>
Yea in theory you could....the intake cam only ...the exhaust cam doesnt move
that would cause probs with piston to valve clearance with to much cam timing
Yea in theory you could....the intake cam only ...the exhaust cam doesnt move
that would cause probs with piston to valve clearance with to much cam timing
11-22-2003, 03:04 PM
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K-motors (well, at least the A and A2) benefit from having an adjustable ex cam sprocket when going to aftermarket cams. I've tuned several cars that gained a few additional hp by tweaking the exhaust cam timing after we'd optimized the intake cam curve with Hondata.
On big cams, you do need to know how much advance you can take before your clearance gets too tight. This means that either the cam grinder should spec out max advance, or you need to mock up the cam. Some manufacturers have tried to eliminate the "i" in i-VTEC only to discover it makes for a much less driveable car.
On the intake cam advance, the ECU actually looks at it as going from 0 to 50 degrees advance. As vtecvoodoo said, its probably +/- 25 from the centerline, but I don't know if anyone has measured it precisely yet.
C_A_T
On big cams, you do need to know how much advance you can take before your clearance gets too tight. This means that either the cam grinder should spec out max advance, or you need to mock up the cam. Some manufacturers have tried to eliminate the "i" in i-VTEC only to discover it makes for a much less driveable car.
On the intake cam advance, the ECU actually looks at it as going from 0 to 50 degrees advance. As vtecvoodoo said, its probably +/- 25 from the centerline, but I don't know if anyone has measured it precisely yet.
C_A_T
11-22-2003, 04:42 PM
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Re: (C_A_T)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by C_A_T »</TD></TR><TR><TD CLASS="quote">Some manufacturers have tried to eliminate the "i" in i-VTEC only to discover it makes for a much less driveable car.
C_A_T</TD></TR></TABLE>
I have often wondered about that-not a big fan of the I-VTEC. I would like to build a K-series motor with adjustable cam gears and no (I) VTEC. Does "much less driveable" mean it won't idle for ****, or are there other driveability issues?
C_A_T</TD></TR></TABLE>
I have often wondered about that-not a big fan of the I-VTEC. I would like to build a K-series motor with adjustable cam gears and no (I) VTEC. Does "much less driveable" mean it won't idle for ****, or are there other driveability issues?
11-22-2003, 08:16 PM
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Re: (Dominican_Kid)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dominican_Kid »</TD></TR><TR><TD CLASS="quote">doesnt the use of toda cams eliminate the "I"??
</TD></TR></TABLE>
Yes it does
</TD></TR></TABLE>
Yes it does
11-23-2003, 02:14 PM
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Re: (dmotoguy)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dmotoguy »</TD></TR><TR><TD CLASS="quote">most highly built motors i know of eliminate the (i)vtec or whatever.. you have to when you go to a very high lift cam
</TD></TR></TABLE>
Explain.
</TD></TR></TABLE>
Explain.
11-23-2003, 02:17 PM
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Re: (dmotoguy)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dmotoguy »</TD></TR><TR><TD CLASS="quote">the ecu will adjust the cam timing to the point you have a valve embedded into the top of your piston... </TD></TR></TABLE>
And that's a bad thing..?
And that's a bad thing..?
11-23-2003, 10:05 PM
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Re: (dmotoguy)
The K-series Hondata that comes out next year is supposed to be able to adjust the intake cam angle. This would negate the need to remove the "i" in iVTEC for high performance K's with high lift cams. Check their web site for more info.
11-24-2003, 07:32 AM
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Re: (b19coupe)
You will lose bottom end. Even midrange torque can be compromised and there are no gains to be had by eliminating i-VTEC in the testing that we've done with various cam manufacturers and engine builders. I've been fortunate enough to spend a lot of time testing Hytech's car, Toda's car (and a variety of development cams that will never see the light of consumer sales) and Ron Acevedo's car (Edo on clubrsx). Ron in particular has tested every commercially available K20 cam out there. And all this testing was done with Hondata riding shotgun to retune the ECU for optimum performance.
Toda built the "VTC" killers because at the time they weren't able to provide people with the ability to limit cam advance. Hytech was the first company I've seen that crafted a mechanical solution to the problem as well as using Hondata (custom tuning that anyone should be able to do come Xmas) to limit cam advance electronically.
i-VTEC broadens the torque curve dramatically and allows surprisingly low rpm switchover points to the big cams. On the order of 4000 rpm or lower for most aftermarket cams out there right now. It is definitely worth keeping if you have the tuning ability (i.e. Hondata or perhaps the AEM EMS version for the RSX). For a very serious race motor that sees nothing below 6k it might be simpler to just eliminate it as your cams might be so big as to remove the ability to advance them (see Toda D's, etc.).
C_A_T
Toda built the "VTC" killers because at the time they weren't able to provide people with the ability to limit cam advance. Hytech was the first company I've seen that crafted a mechanical solution to the problem as well as using Hondata (custom tuning that anyone should be able to do come Xmas) to limit cam advance electronically.
i-VTEC broadens the torque curve dramatically and allows surprisingly low rpm switchover points to the big cams. On the order of 4000 rpm or lower for most aftermarket cams out there right now. It is definitely worth keeping if you have the tuning ability (i.e. Hondata or perhaps the AEM EMS version for the RSX). For a very serious race motor that sees nothing below 6k it might be simpler to just eliminate it as your cams might be so big as to remove the ability to advance them (see Toda D's, etc.).
C_A_T
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