You too? Pffffff...

 

EP3 vs Accord R 2.2. K20 vs h22. Same dyno same day.

 

EP3 vs Accord R 2.2. K20 vs h22. Same dyno same day.

The torque shape of the K20 looks like stock, despite VTEC is a bit late, but not beyond 7500 rpm. What are the modifications on each of them?

 

@LotusElise
Both are stock cars, nothing is touched. Was interesting to me seeing what different R engines can do in Oem trim.

 

 

 

Fucking awesome.

Could you tell the weight and more or less rest the setup of the car (tires, aero, etc.).

I’ve also got an ep3 and It’ll probably have a k24 inside in the future

 

Finally hit the Dyno with the 86 CRX SI

JDM K24a
Motor internally is stock other than Type S oil pump and 50 degree VTC
3“ custom intake with block filter with bell mouth
Accord TB and stock RBB manifold opened up to 64mm and matched by King Motorsports
K tuned swap header
3” header back exhaust with test pipe
91 octane pump gas

Tuned XACT dyno in Tempe AZ, he tuned it for the track more so than the street. He explained he would have Vtec switch over differently if it was a street tune. Our goal was to be at a 10:1 power to weight ratio, to max out the car for the class I race in. We did it 220 wheel hp and 200 ft lbs torque.

Untitled by Victor M, on Flickr

Untitled by Victor M, on Flickr

 

Congratulations @cspcrx to the successful tuning session. Looks like the engine has a good breathing capacity around 4500 rpm. How much IGT could you run beyond 5700 rpm, where the breathing capacity brake down harder?

 

He did show me there was a choke point at about 4500. He didn’t know if it was just a resonance if the intake manifold or what. We didn’t pull the intake tube to see if it went away. Vtec is switching over at 4700 rpm. I would liked to have seen the toque curve be a bit flatter and less peaked. But the overall curve is nice.

not sure if this means or what would cause it. If it wasn’t breathing well it wouldn’t make power up top.

 

He did show me there was a choke point at about 4500. He didn’t know if it was just a resonance if the intake manifold or what. We didn’t pull the intake tube to see if it went away. Vtec is switching over at 4700 rpm. I would liked to have seen the toque curve be a bit flatter and less peaked. But the overall curve is nice.

I would assume a header resonance overlays a IM resonance. With the stock camshafts you have a resonance at low speed cam (intake duration is about 215°@1 mm) at 4500 rpm on the 3rd order. The volumetric efficiency at 4400-4700 rpm is around 127 %, assuming a drivetrain efficiency of 85 %, which is very high. Saw this the first time on a stock engine. To smooth that out, because of driveability, I would have tested lower VTEC switch points, as the resonance is camshaft duration depended and get shifted by around 500 rpm higher with the high speed cam, which separate the two resonances of H and IM and form a lower and more smoother torque curve.

not sure if this means or what would cause it. If it wasn’t breathing well it wouldn’t make power up top.

You may not have expected not that much power. What I've meant was, compared to the best point of VE = 127 %, the peak power VE is quite lower, about 107 %. The later is typical, but the former not, which makes that engine different to drive, especially on lower speeds.

Torque curve shape:
Considering the 2nd order of the IM is at around 7700 rpm on stock cams, somewhere beyond 7000 rpm the reducing the scavenging efficiency. Looking at the 4-2-1 header system, which is maybe 950 mm in total, just to be able to match a 2nd order resonance at 4500 rpm (which is the double resonance point), the header length design is it likely not. Seems something a flow-sided restriction at intake or and exhaust side (head port, runners just to name a few). Bigger cams would change everything, maybe not to the better, beside the high door opening.

 

really appreciate you sharing your experience. May have to go to my buddy, who also has the same dyno and would charge much less, try lowering the Vtec to see if it reduces some of this dip and drop off.

 

Typically a lower vtec engagement would smooth that transistion out, on most street cars that my tuner does, we see the crossover around 4000-4200 typically

 

Tuner said an RBC would help a lot and since I have the 50 deg VTC I wouldn’t lose a lot of torque. Going to track it and see how it feels. I ran some calculations and shifting at 7k 2nd gear through 5th keeps me at or just above peak torque on each shift. See how it behaves,

 

If you could fit ported RRC of ultra street you would gain 25-30hp and wouldn't miss any of low tq.
From my research Rbc is not the mani you wanna go for if you want to max out your combination.
This guy has gained 15hp with ported ultra street vs stock rbc

And looking at Gears And Gasoline graph his ported RBC takes a dive after 7000rpm. But maybe that is because of header that he is using or maybe intake manifold but that should'nt happen.

 

Is it you in the attached picture @Kowalski999?

 

Not me, that is guy form gears and gasoline youtube.

 

The thing is I don’t need more hp, longer power curve wouldnt be bad. A longer torque is what i would. Really like to see. One that less peaky. I am happy with the 200 ft lbs just wish it didn’t fall off so quickly

 

This view of the graph, similar scale makes it look a bit less extreme

Untitled by Victor M, on Flickr

 

That is definitely function of the header 15hp drop past 6800rpm is real big. On my setup with RBB max TQ was at 6000rpm and there was only 5hp drop past 7400rpm. But than you have big TQ gain over my setup on low/mid.
You have data from Holdeners testing and 4-2-1 header (21inch primes /15inch secondary) that he was using was working extremely well with rbb manifold.

My is green vs his read with RBB

My green vs his blue with Skunk2 pro intake manifolds.

 

I don't understand your final two graphs, is your green line supposed to be the same in both?

 

@mrluke
No it is not same.Both are overlay of "same" mods for mods graph.

So first green line is my rbb+ header combo vs holdeners rbb+ header combo.

Second is my ported "pro street" manifold + header combo vs holdeners pro street + header combo.
Just to note that he is using pre fl k24a2 so same as my k24a3 where in second graph with pro street manifolds I have upgrade to k24z3 cam vs he still on stock cam.

 

My big TQ numbers down low are a result of the 50 degree VTC. I’m running a 4-2-1 header which also is midrange focused. So you think the top end power loss is due to the header not intake?

 

How much vtc are you using at low and mid? I remember some tuners teling me that 50 vtc didn't do much on stock engine with rbb manifold and that I shouldn't bother instaling it. So at that time I gave up on using it as my first plan was just to port stock rbb manifold put 50vtc gear and leave it at that.

I dont see what else would cause it except for the header.

Here is one more example :
We have same parts regarding engine and intake manifolds. He has real s2ps where my is fake ported s2ps and headers my is copy of weaponR and his is PLM, cars are TSX.
He has big boost of torq at 5200rpm and engine rolls over past 7300rpm.
Where my powerband is flat and never rolls. Only difference is in headers.
Edit:
That is 18hp drop... And on graph from gears and gasoline he has over 40hp drop from 7000rpm to 8500rpm. That is crazy.

 

I remember some tuners teling me that 50 vtc didn't do much on stock engine with rbb manifold and that I shouldn't bother instaling it.

Indeed, the RBB IM has a resonance at 4500 rpm, which helps to scavenging quite good, but there is still a use of the bigger VTC range from 45° till reaching the 25°. The better the header at midrange, the earlier the VTEC, the more VTC is needed. I am talking about VTEC switch points of 3500 rpm. If you implement a RBC IM instead, the 50° VTC is really needed, as that IM has no such powerful resonance anywhere.

 

So to answer a few questions. VTEC range is set to low of 4000 and high of 5000. So that means, based on the graph the drop is occurring on the high lobe not low.

here is a picture of the table. Hope this is what you were asking to see.
Untitled by Victor M, on Flickr

 

So to answer a few questions. VTEC range is set to low of 4000 and high of 5000. So that means, based on the graph the drop is occurring on the high lobe not low.

Wow, thanks. When VTEC kicks in at 4000 rpm that resonance would tell me my RBB runner length is wrong. I've took it from K20a.org. Would you be so kind to measure the RRB runner length from flange surface to plenum for the symmetry line of the runner? At K20a.org are two statements, one is 320 mm and the other one is 380 mm. I doubted on the second, but if I recalculate it for the high speed cam duration it has to be the second.

here is a picture of the table. Hope this is what you were asking to see.

That is much appreciated, thanks.

• The WOT VTC looks good to me and very plausible compared to the torque graph.
• I know for race applications the part load VTC is always a compromise between efficiency and VTC readiness at WOT after shifting. I run different strategies there, having different mixture of that compromise. But I would assume racing is always going through the gears. For example, if you go in a 4th gear bend with 6500 rpm, too high to shift up, and go of the throttle a bit the VTC mechanism will turn into 40°, according the High speed cam VTC map, when diving into part load. Through the bend you will control the over- and understeer with the pedal, while it can happen that the load point locates temporary at the 25° column (= -7.6 inHg) and at the at bend outlet you push the throttle to full, VTC has to turn from 25° to again to 40° at e.g. 5250 rpm, which takes about 150 ms, where transient lambda and response are lacking and challenging to tune that transient crispy and sound (not tuneable with the Honda ECU functionality offered by KPro).
• During shifts and deceleration it can be the VTC turns again from actual to 40° and back to 25° in the vaccum left side MAP, when coming back it goes the same way, triggered to 40° back to 25° and to actual which is likely 40°. What is the cause for that back and forth? Should it soften the torque rise for better transient grip in bends?
• With rework of the secondary runners of the header you would be able to bring up a resonance at higher engine speed to extend the 40° area and flat out the torque curve too

Would be interesting to see the ignition timing map with respect to the above shown VTC map .

 

It is just interesting to me to see what setup us using regarding vtc. Nothing more than that.

4age garage has got his hands on k24 ep3 with bc cam so he will do bunch of testing with it.
Gonna be fun watching him poke around with k24 and ge already started with clear cut testing how vtc affect power.

 

Came here to post that, you beat me to it

 

I don’t know why there is the back and forth from the 40 to 25. i would have to ask the tuner.

I could send you the file to examine if that’s easier or a screen shot of that table.

 

@LotusElise I have RAA taken apart here and it is 300mm long. Plenum section 150mm and head flange section 150mm. Who ever measured 380mm was measuring over the top of the runner - the longer radius so there is where that 380mm comes from.
RBB should be a bit shorter than RAA from what I have heard.

 

@LotusElise I have RAA taken apart here and it is 300mm long. Plenum section 150mm and head flange section 150mm. Who ever measured 380mm was measuring over the top of the runner - the longer radius so there is where that 380mm comes from.
RBB should be a bit shorter than RAA from what I have heard.

Thanks for your replay @Kowalski999. Was this measured at centerline from flange surface to bell mounth end?

 

Fresh dyno numbers!

I posted a dyno here some time ago, and since then I've put ~15,000 miles on the engine and decided to upgrade the top end since I always had leaking valve seals and it burned about a litre of oil per 1000 miles

Car is 2016 Subaru BRZ with Kpower industries Kswap kit

My goal was to focus on mid-range as well as idle quality. I am happy to report it idles just like stock and is even quieter than when it had the stock head on.

Build sheet:
2006 k24A2 from a junkyard USDM TSX - unknown miles, stock bottom end
4 Piston TSX Pro Head
Type-S oil pump
Toda A3 camshafts
Bosch 74mm TB
Mishimoto Powerstack Performance Air Filter
Kpower Industries RWD intake manifold
Kpower Industries Header
X-Force 3" dual exhaust
Toda Valve Springs
Ferrea Valves
OEM retainers, locks, seats
Viton Valve Seals
Toda Timing Chain
Toda Oil Pump Chain
Toda Chain Tensioner
ARP Head Studs
OEM Head Gasket
Trac Truf 40 degree VTC limiter
OEM guides
DragCartel lower guide

264.3whp
201.3wtq
Gas is mix of 93 and E85, about E45
AFR was about 12.8:1
Weather was 81F / 27C
Tuned by GearHeads Autofab in Pflugerville, TX, USA

Let me know your thoughts!

 

Fresh dyno numbers!

I posted a dyno here some time ago, and since then I've put ~15,000 miles on the engine and decided to upgrade the top end since I always had leaking valve seals and it burned about a litre of oil per 1000 miles

Car is 2016 Subaru BRZ with Kpower industries Kswap kit

My goal was to focus on mid-range as well as idle quality. I am happy to report it idles just like stock and is even quieter than when it had the stock head on.

Build sheet:
2006 k24A2 from a junkyard USDM TSX - unknown miles, stock bottom end
4 Piston TSX Pro Head
Type-S oil pump
Toda A3 camshafts
Bosch 74mm TB
Mishimoto Powerstack Performance Air Filter
Kpower Industries RWD intake manifold
Kpower Industries Header
X-Force 3" dual exhaust
Toda Valve Springs
Ferrea Valves
OEM retainers, locks, seats
Viton Valve Seals
Toda Timing Chain
Toda Oil Pump Chain
Toda Chain Tensioner
ARP Head Studs
OEM Head Gasket
Trac Truf 40 degree VTC limiter
OEM guides
DragCartel lower guide

264.3whp
201.3wtq
Gas is mix of 93 and E85, about E45
AFR was about 12.8:1
Weather was 81F / 27C
Tuned by GearHeads Autofab in Pflugerville, TX, USA
View attachment 111623

Let me know your thoughts!

Those toda a3 cams make a nice torque curve. How's the idle?

 

I need 950-1000 rpm at idle with my Today A3 on a K20a2.
It idles fine and uniform at 850 rpm, but idle torque is so low, it is very easy to stall trying to roll or maneuver.
K24 may behave differently.

 

It idles fine and uniform at 850 rpm, but idle torque is so low, it is very easy to stall trying to roll or maneuver.

Your engine has an additional friction source: a supercharger. My NA 86x86 and the IGT tune let it pull the car without throttle from standstill to idle in gear when clutch is released with attention.