Making the K hold torque to 8krpm... - Page 2 - K20A.org .:. The K Series Source . Honda / Acura K20a k24a Engine Forum
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Old 07-12-2008, 06:57 AM   #21
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Default Re: Making the K hold torque to 8krpm...

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Originally Posted by signalpuke View Post
Hondata has the dyno plots in their training videos. http://www.hondata.com/techk-protraining.html
Video 9 has an overlay of dyno pulls from each cam angle 0-50. It shows you that even at 6000rpm, VTC is at work, optimizing torque. At 6000rpm, the graphs show 50deg VTC is 5lb-ft higher than 30deg. When you start higher, you appear to fall further.

Overlay some B-series and K-series dyno plots that are from 2.0L builds and you'll get an even clearer picture of how VTC raising up the midrange is affecting your perceptions of top end power falloff. A 2.0L K-series will have no trouble keeping up with a 2.0L B-series on top end, but will destroy it in midrange so long as VTC is being utilized.
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Old 07-12-2008, 08:18 AM   #22
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Default Re: Making the K hold torque to 8krpm...

Here's HIGH CAM COMPOSITE




Here's LOW CAM COMPOSITE





OVERALL CAM COMPOSITE




VTEC Composite Crossover

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Old 07-12-2008, 05:12 PM   #23
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Default Re: Making the K hold torque to 8krpm...

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Here's HIGH CAM COMPOSITE

this is what chunky is talking about... the 40 deg curve loses about 26 ft/lbs from 6k to 7.5k, while the 10 degree curve only loses about 12 ft/lb over that same range.. but thats because at 40degrees it was making 16 ft/lbs more than at 10 degrees.. now imagine that 10 deg. curve as a B series curve, since it cant benefit from the midrange gains that VTC give
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Old 07-12-2008, 08:32 PM   #24
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Default Re: Making the K hold torque to 8krpm...

Listen to chunky. The midrange is what really seperates the k motors from everything else.
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Old 07-14-2008, 05:04 AM   #25
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Default Re: Making the K hold torque to 8krpm...

I don't understand what you are saying? These motors make as much tq at 3-3500 as they do at 8-8500, and like you said there is not B series going to be making these kinds of torque numbers? I haven't seen a perfectly flat torque band on any NA motor... It has to peak somewhere, and I thin the middle of the powerband is the optimal place for it to peak...
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Old 07-14-2008, 08:05 AM   #26
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Default Re: Making the K hold torque to 8krpm...

Of course, because that is where most cars stay at. The midrange. And i do use the term MOST loosely.
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Old 07-14-2008, 08:40 AM   #27
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Default Re: Making the K hold torque to 8krpm...

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Originally Posted by jon v View Post
I haven't seen a perfectly flat torque band on any NA motor... It has to peak somewhere, and I thin the middle of the powerband is the optimal place for it to peak...
Optimal for daily driving maybe, not for racing. You stay in the upper 2500rpms when your racing with a nicely geared transmission; so you want torque in that area to be as flat as possible. This just isn't the case with the K-series unfortunately; (unless you have a stupid low redline like 6500 or 6k). I'm just one who likes to rev. You have to think of it like this, for every 10wtrq more you can hold till 8k, its 20 more whp.
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Old 07-14-2008, 09:45 AM   #28
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Default Re: Making the K hold torque to 8krpm...

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Originally Posted by unsivil_audio View Post
Optimal for daily driving maybe, not for racing. You stay in the upper 2500rpms when your racing with a nicely geared transmission; so you want torque in that area to be as flat as possible. This just isn't the case with the K-series unfortunately; (unless you have a stupid low redline like 6500 or 6k). I'm just one who likes to rev. You have to think of it like this, for every 10wtrq more you can hold till 8k, its 20 more whp.
I think i understand the disconnect now. But what your asking for, your getting, you just don't know it(which is good cause its like finding a $20 in your couch .)

Look at the "Before" line on my stock 24A2 before I started tuning. Its Torque curve keeps relatively the same numbers all the way to redline(minus the fuel dips and bumps). Very much like our H and B series brethren. Referencing the 'After' curve now, the very reason torque falls off as hard towards the end, is because it is making so much more torque in the mid/mid-high end of the curve.


However, when you compare the final tune to some B-series examples, this is what it looks like. Keep in mind a K20A/A2 will make similar hp numbers but shift the torque curve down and to the right a grand or so (which just moves the HP curve straight to the right). The B-series for comparison are a bone stock JDM B18-R(blue) and a semi built Ls-Vtec(green). The point really is, at higher RPM's, the K absolutely does make much more torque then B's. It just makes a monstrous amount more in the mid range.

As a side note we later made 201whp with the bolt on type r, no cams just IHE. Nice little motor

Last edited by TheMidasTouch; 07-14-2008 at 09:48 AM.. Reason: I'm editing cause i'm a dummy :)
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Old 07-14-2008, 10:26 AM   #29
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Default Re: Making the K hold torque to 8krpm...

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Optimal for daily driving maybe, not for racing. You stay in the upper 2500rpms when your racing with a nicely geared transmission; so you want torque in that area to be as flat as possible. This just isn't the case with the K-series unfortunately; (unless you have a stupid low redline like 6500 or 6k). I'm just one who likes to rev. You have to think of it like this, for every 10wtrq more you can hold till 8k, its 20 more whp.

You are obviously talking drag racing?

It sounds like you want the torque of the bigger 2.4L motor in the power band of the smaller stroke 2L... the bigger the stroke the earlier the torque kicks in in the power band no?
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think about what you are saying here. educated people are saying that some portions of this safety device are in direct conflict with this little thing called physics and you are willing to ignore that simply because of the cage builders reputation? that sounds like religion to me. welcome to the church of fanboyology.
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Old 07-14-2008, 10:35 AM   #30
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Default Re: Making the K hold torque to 8krpm...

I'm just talking optimum performance in general. I mean, the way I look at it, its 2.4l, its gone make some good midrange torque anyways due to displacement.

Yeah the more I look at it, the more I just think its a result of more stroke. I would think it there would be a way to compansate for it however, with cams and/or head porting.
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Old 07-14-2008, 10:39 AM   #31
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Default Re: Making the K hold torque to 8krpm...

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Originally Posted by unsivil_audio View Post
Optimal for daily driving maybe, not for racing. You stay in the upper 2500rpms when your racing with a nicely geared transmission; so you want torque in that area to be as flat as possible. This just isn't the case with the K-series unfortunately; (unless you have a stupid low redline like 6500 or 6k). I'm just one who likes to rev. You have to think of it like this, for every 10wtrq more you can hold till 8k, its 20 more whp.
Not true. You don't want it to be as "flat" as possible. You want the torque to be maximized as much as possible. A k-series is going to make the same or better power up top as a b-series of the same displacement.

TheMidasTouch posted a nice graph displaying how the appearance of a flat torque band can be deceiving.
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Old 07-14-2008, 10:41 AM   #32
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Default Re: Making the K hold torque to 8krpm...

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Originally Posted by unsivil_audio View Post
I'm just talking optimum performance in general. I mean, the way I look at it, its 2.4l, its gone make some good midrange torque anyways due to displacement.

Yeah the more I look at it, the more I just think its a result of more stroke. I would think it there would be a way to compansate for it however, with cams and/or head porting.
If you looked at one of the graphs that Nikos posted, there is a built k24 that revs to 10k while holding torque. It's all in the combination. It's not something you can just slap together, but it is possible. Think about it, almost 400hp at 9000rpm. It's ridiculous. I never dreamed that would be possible when I started tuning n/a hondas over a decade ago.
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Old 07-14-2008, 10:41 AM   #33
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Default Re: Making the K hold torque to 8krpm...

^---lol are you serious, is that what you call holding torque? Continuing to make horsepower is not holding torque.

Yes however, I have yet to see a K-series with a rising torque curve in the upper 2500rpm, so thats why I didnt say it.
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Old 07-14-2008, 10:44 AM   #34
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Default Re: Making the K hold torque to 8krpm...

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^---lol are you serious, is that what you call holding torque? Continuing to make horsepower is not holding torque.

Yes however, I have yet to see a K-series with a rising torque curve in the upper 2500rpm, so thats why I didnt say it.
In absolute terms, I have yet to see a B-series that is making 200+ lb-ft of torque at 10k rpm.

Quote:
Originally Posted by nikos
Forget about the midrange, look at absolute numbers. It doesn't matter if the torque is rising or falling; if the ACTUAL torque is greater, you will be going faster. Period.

I don't think you quite realize how difficult it is to sustain torque production on a big displacement motor into high revs.
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Old 07-14-2008, 10:57 AM   #35
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Default Re: Making the K hold torque to 8krpm...

You may be right, I dont think its rocket science either though.

A 2nd look at that dynograph though, and that would be a totally accpetable powerband for me (considering I'm only wanting to rev to 8500 or so). If I could have that on a street car but at a lower power level I would be perfectly happy.
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Old 07-14-2008, 11:31 AM   #36
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Default Re: Making the K hold torque to 8krpm...

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Yes however, I have yet to see a K-series with a rising torque curve in the upper 2500rpm, so thats why I didnt say it.
Thats the thing mang, if your torque is still rising then your red line needs to get pushed. Realistically, you don't want to shift until your overall thrust curve per gear intercepts the next one.

This means that your torque will need to be decreasing fast enough by rpm so that your hp output times the gear multiplier equals the next gears output at the given intercept speed. So on any well targeted/designed motor, torque should always fall off hard before red line. Its what you use to gauge where red line really should be.

On some unbuilt B-series, raising the red line isn't an option so to make the most peak whp tuners(on demand most of the time) will push the torque as high as possible in the rpm range ignoring power band because of what you were saying(20whp for 10lbs of torque) Which, for anyone who doesn't know already, comes from the calculation for Horse Power. HP is really only a function of torque vs rpm.

HP = (Torque * RPM)/5252
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Old 07-14-2008, 11:44 AM   #37
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Default Re: Making the K hold torque to 8krpm...

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Thats the thing mang, if your torque is still rising then your red line needs to get pushed. Realistically, you don't want to shift until your overall thrust curve per gear intercepts the next one.

This means that your torque will need to be decreasing fast enough by rpm so that your hp output times the gear multiplier equals the next gears output at the given intercept speed. So on any well targeted/designed motor, torque should always fall off hard before red line. Its what you use to gauge where red line really should be.

On some unbuilt B-series, raising the red line isn't an option so to make the most peak whp tuners(on demand most of the time) will push the torque as high as possible in the rpm range ignoring power band because of what you were saying(20whp for 10lbs of torque) Which, for anyone who doesn't know already, comes from the calculation for Horse Power. HP is really only a function of torque vs rpm.

HP = (Torque * RPM)/5252
Thanks for the well worded explanation. That is what I was trying to convey with the 15k redline comment, I wasn't trying to be an ass lol.
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Old 07-14-2008, 11:54 AM   #38
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Default Re: Making the K hold torque to 8krpm...

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Thanks for the well worded explanation. That is what I was trying to convey with the 15k redline comment, I wasn't trying to be an ass lol.
Oh man, I wasn't referencing your post, and I agree with you of course. I was just wording the concept differently. Different strokes for different folks when were learning.

Really though, traction willing, we want more of all(torque, gearing, rev stability, etc...) in all rpm ranges
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Old 07-14-2008, 12:33 PM   #39
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Default Re: Making the K hold torque to 8krpm...

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You may be right, I dont think its rocket science either though.

A 2nd look at that dynograph though, and that would be a totally accpetable powerband for me (considering I'm only wanting to rev to 8500 or so). If I could have that on a street car but at a lower power level I would be perfectly happy.
As far as delaying a sharp torque falloff in a high displacement 4 banger? It's not rocket science, but there is a science to it.

Anyhow, just compare the raw numbers on torque for a 2.0L b-series and a 2.0L k-series at 8000rpm. The K-series is no high RPM slouch. You can build a k-series that loves to rev, that is reliable, and that isn't ridiculously expensive.

It won't have the same power delivery as the b-series, but you'll be going faster regardless of how the power delivery feels.

Anyhow, if you're looking to rev to 8500, check out my latest dyno. It's pretty linear in the RPM range you specified, but I'm hoping that a better header will bring up my midrange even more to 160+ lb-ft of torque.

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Old 07-14-2008, 12:36 PM   #40
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Default Re: Making the K hold torque to 8krpm...

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As far as delaying a sharp torque falloff in a high displacement 4 banger? It's not rocket science, but there is a science to it.
I agree, I more or less think engine building is an artform. It takes a very fine tuned piece to amaze the masses.

BTW, your dyno looks good, however I'm gonna venture a guess and say that you have a k20 judging by that torque curve.
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