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Re: Official: Dyno Chart Comparison & Calibration Registry

K24a3
98ron
RRC IM
DC 2.2 cams
TSX 11:1
Supertech valve train
ASP header
Stock catback

Upgraded catback slightly to tanabe medallion.
Below dyno was stock catback and loose CAI
 

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Hello guys,

First of what does a stock or mild modified K20A2 2L engine give you in a Dynapack dyno? Only intressted in hub horsepower so the reference is correct.

I just built a new engine with 12.5CR pistons CNC ported head catcams cams, jenvey 50mm throttles, 750mm long exhaust manifold and 3" exhaust system and it puts out 220whp and 200nm on 102oct race fuel and I would like to have seen 230-240 range.

It should put out more right?
 

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Arouse the DAMPFHAMMER!
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I just built a new engine with 12.5CR pistons CNC ported head catcams cams, jenvey 50mm throttles, 750mm long exhaust manifold and 3" exhaust system and it puts out 220whp and 200nm on 102oct race fuel and I would like to have seen 230-240 range.
If you talke about wheel rated figures, we must know if RWD-Front Engine, RWD-Mid Engine or if its a FWD and Front Engine chassis. Beside that I would like to know which one of the CatCams models you choose. They produce for stock mostly race cams, only a few are for that power range. Also I would like to know more about the header dimensions, exhaust, intake runner length and so on. Over this I would prefer to see the calibration of the engine tune via Email.

...I’m confused why you would match a ported head to such tiny ITBs??
Stock head port entrance area corresponds to a diameter of 46.5 mm, only extrem drag race engine heads would go over 50 mm diameter. Normally you find plenty of room to match a 50 mm runner to an K20 head. Normally, could be some think much bigger is better than just big :D.
 

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Arouse the DAMPFHAMMER!
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People have posted dyno graphs of 54 mm vs 60 mm ITBs and the top end gains are definitely there. Also, big sponsor drag teams have the resources to dyno test multiple different engine mods. I refuse to believe they choose the larger ITBs simply because “bigger is better”.
Hi BlackNDecker, I agree with you concerning power level and I remember the measurement of K20a.org member ukir85, which underlines your statement. But this wasn't my point. Mine was just the 50 mm ID of the runner doesn't mean automatically you have an port match issue from runner to head. I was referring to your comment below, which implied for me there would be an issue.

BlackNDecker said:
...I’m confused why you would match a ported head to such tiny ITBs??
The issue of the OP seems to me to lay at a different end, 147 wftlb and 200 whp would only fit to an RWD chassis with a drivetrain efficiency of around 82 %.
 

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The ITBS are jenvey tapered 50mm I think the funnels are 55 I have to measure to be sure. The car is a rally car type-r with seq gearbox.

Cams are similair with the this grind, minor changes. first cam are 315deg and 2.3mm ift in tdc. They are now at 3.0mm. And vtec cam are 362deg - 13.5mm


304°/304° - 225°/225° - 11.50mm/11.50mm - 1.45mm/1.50mm (pri)
304°/304° - 225°/225° - 11.50mm/11.50mm - 1.45mm/1.50mm (sec)
352°/340° - 273°/263° - 13.50mm/12.50mm - 4.85mm/4.10mm (Vtec)

Using Hondata I dont have any WOT logs, but it wont give more power its not in the tune. Im tuning the car my self.

To be mentioned it gave me 220whp about same powerband with stock JDM pistons, stock head and alittle more aggresive cams. Now the head have bigger valves, cnc ported, jenvey, new custom extractor and 3" system but only making about the same. Oh and high CR pistons now 12.5 with machined head prob just under 13.0 in CR. something is weird here.
 

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Arouse the DAMPFHAMMER!
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...The car is a rally car type-r with seq gearbox.
Are you sure you calculated the wheel-to-engine speed correct?

Cams are similair with the this grind, minor changes. first cam are 315deg and 2.3mm ift in tdc. They are now at 3.0mm. And vtec cam are 362deg - 13.5mm
These are similar to the full race spec camshafts of CATCAMS.com. Your cam phasing is pretty much retarded, normally you should have a valve lift of around 5-6 mm at TDC depending on your piston to valve clearance at 7° ATDC. Did you measure the minimum valve to piston and valve to valve clearance? If you run them to much retarded you shoo all valuable ponies almost over the entire revving band away

Using Hondata I dont have any WOT logs, but it wont give more power its not in the tune. Im tuning the car my self.
I won't critisize your tune, just give you a second view to it and I would understand it better why it is like that like it is.

...Now the head have bigger valves, cnc ported, jenvey, new custom extractor and 3" system but only making about the same. Oh and high CR pistons now 12.5 with machined head prob just under 13.0 in CR. something is weird here.
What fuel did you use for tuning?

Here is one of the runs making barely 220whp and under 200nm.
For a race cam the dip before VTEC is inacceptable. Race cam need compromise a higher idle speed for a better low speed torque, which this cam doesn't do. Did you remove the VTC mechanism?

Please send me the calibration and if possible a log file, this looks like multible issues in the field of engine setup and tuning. Again, this is not for to critize you just for analysis of the root cause. The more information you can give to me the better we can bring back the horses to your engine.
 

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Are you sure you calculated the wheel-to-engine speed correct?
Yes the ratios are correct.

These are similar to the full race spec camshafts of CATCAMS.com. Your cam phasing is pretty much retarded, normally you should have a valve lift of around 5-6 mm at TDC depending on your piston to valve clearance at 7° ATDC. Did you measure the minimum valve to piston and valve to valve clearance? If you run them to much retarded you shoo all valuable ponies almost over the entire revving band away
Well no, the cam is advanced. 3mm is measured on the first cam not vtec one. There is not enough clearance to run it higher on first cam when vtec cam engages. I will take off the head and measure exacly how much space there is when vtec is engaged. But then I need to lock vtec in place.

What fuel did you use for tuning?
Have tested both 110oct and 102 race fuel.

For a race cam the dip before VTEC is inacceptable. Race cam need compromise a higher idle speed for a better low speed torque, which this cam doesn't do. Did you remove the VTC mechanism?
Toda racing chain and camgear no mivtec/adjustable cams now. Also Toda chain tensioner.
 

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I would say the cams are to big for this engine or some sort of mismatch of the components. For me 273° duration @1mm (or even more if full duration is 362°) is HUGE for this rev range and 2.0l engine. But before I make my final statement, post the dimensions of the exhaust manifold.
You also said that you have bigger valves. Inlet, exhaust, or both? What size? Who did the head porting? Any photos of the head ports, itbs fitted and manifold?
 

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Arouse the DAMPFHAMMER!
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...no, the cam is advanced. 3mm is measured on the first cam not vtec one.
You are the first one measuring the low speed cams :wink:. Sorry for my wrong assumption.

Normally the high speed lobs are the one you want to know the piston to valve and valve to valve clearance, as these should be the only one touching the piston or the exhaust valves, otherwise I would assume a NON-VTEC setup or a too huge low speed cam which likely need an increased idle speed of more than 1200 rpm.

Have tested both 110oct and 102 race fuel.
Thanks

Toda racing chain and camgear no mivtec/adjustable cams now. Also Toda chain tensioner.
This explains much. For a non cam phasing setup you need to adjust for an compromise, not to much advanced, but also not retarded for max power only, just like that so you find the best powerband you need. Advancing support always the left to mid side of the engine speed band of that cam (here high speed powerband). In your case of having a pure high power camshaft you need to think about more retard and to increase your engine speed. Like drmo already stated, this is a 273°@1 mm lift cam, which is for 86 mm stroke a pretty looooong duration. For a 11.500 rpm 78.5 mm stroke engine you don't need to go over 265°@1 mm with the right induction and header design, just for your comparison.

I would say the cams are to big for this engine or some sort of mismatch of the components...
I would also agree with you, I also wanted to wait for further information, especially the ignition data could tell us more about a VE or combustion related issue. But my feeling is also more into VE direction, just because of the duration, which need an awesome induction and piston speed to get this chab running.
 

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Arouse the DAMPFHAMMER!
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+1mm both in and ex...
Recently this year I did a concept for an Bonneville engine spec'd to 360 [email protected] rpm, it shows there is no need to go that extrem. What the port want is flow at highest velocity possible. Flow flux alone is nothing, it is even worth if it's increased level is reached only by increasing the port cross section.

At exhaust you easily break into sonic area all the time of the exhaust valve opening duration, this means velocity is fixed to temperature only, so impulse into the header. Increasing the port diameter doesn't mean to increase it, it reduces it as Mach 1 is mass limiting! Only if you open the throat of it than you can increase it, what isn't needed for an 500 ccm cylinder.

At intake side it is a bit different, here impulse velocity isn't really limited to sonic conditions as it will not be reached under NA requirements, the pressure drop is far from being critical (= sonic speed is reached) so more cross section can mean more impulse as mass and velocity can be increased if the surrounded conditions like engine speed, stroke height, port and valve seat design, valve design, header design, ... support it. But at around 0.6 Mach is end of fun, as the pressure conditions won't give you the chance to increase it more, just if you have forced induction.
 

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Thanks, but still waiting on the header data. From your data that the length of the header is 750mm I can see why you weren't making power past 8600. The header is too long and probably the diameters are too small. Something is limiting the engine to breathe and the exhaust is not helping.
The power starts to drop after 8600rpm which is strange for a 273°@1mm lift intake cam. As LotusElise said, too much duration for 86mm stroke.

I also wouldn't go with bigger exhaust valves, especially not on a 2.0 NA engine that already has 30mm exhaust valve. Valve shrouding with bigger than stock exhaust valves is also a problem on 86mm bores.
 

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06 accord, Stock k24a8, 91oct, 6psi, t3/t4 CX racing turbo, 3" turbo back exhaust with hi flow cat, vibrant muffler, dei turbo blanket. 252whp 236tq
 

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Arouse the DAMPFHAMMER!
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06 accord, Stock k24a8, 91oct, 6psi, t3/t4 CX racing turbo, 3" turbo back exhaust with hi flow cat, vibrant muffler, dei turbo blanket. 252whp 236tq
There is something wrong in my understanding of this engine. The peak power levels lead just to an boost level of 1 psi in my VE calculation. Even if the A8 head is a huge restriction if I set VE to 6 psi, which you have stated, the engine efficiency is 6 %-points below what we see typically on turbo'd 87x99 engine setups here.

Could you please share following data:
  • peak power engine speed
  • injector size rated on 43.5 psi or an given pressure level
  • injector duty cycle at peak power
I would recalculate with those numbers your engine. There is something wrong with the data or your engine...this is for sure.
 

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06 accord, Stock k24a8, 91oct, 6psi, t3/t4 CX racing turbo, 3" turbo back exhaust with hi flow cat, vibrant muffler, dei turbo blanket. 252whp 236tq
There is something wrong in my understanding of this engine. The peak power levels lead just to an boost level of 1 psi in my VE calculation. Even if the A8 head is a huge restriction if I set VE to 6 psi, which you have stated, the engine efficiency is 6 %-points below what we see typically on turbo'd 87x99 engine setups here.

Could you please share following data:
  • peak power engine speed
  • injector size rated on 43.5 psi or an given pressure level
  • injector duty cycle at peak power
I would recalculate with those numbers your engine. There is something wrong with the data or your engine...this is for sure.
Injectors are 850s from performance fuel injection in Canada. I haven't got any fuel pressure or injector duty cycle numbers for you. This is my first turbo build, and alot of the tuning stuff is beyond me
 

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