MikeySpec

Once upon a time by my buddy David had this awesome K20 Integra that eventually ended up evolving itself from a daily driver to a well setup track car. He spent countless days at the track dialing this car in to the best of his ability. Locally it became one of the fastest FWD cars around and was putting down some very impressive lap times for its mild output and simple setup. It eventually saw an upgrade from the K20A to a 2006 K24 longblock.




Modifications were as follows
- Rcrew Drop In cams (from 2009)
- Rcrew Header
- RBC manifold w/ 70mm TB
- 50* VTC Gear
- K20a2 Oil Pump
- Custom 3 Inch Exhaust
- RDX 410cc Injectors
- Kpro Tuned





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This is what it made with the modifications listed on 93 octane. As a sidenote we did do an e85 tune as well that gave us roughly a 3% gain to the wheels.



Eventually David bought a Miata. Then he tracked it. Then he joked about how awesome it would be to put the K24 from the Integra into the Miata. Then the K24 from his Integra ended up in the Miata and eventually a bolt in kit came about. You can find more details about that at Kmiata.com.





I have been on board with David from the get go to help with engine tuning and development. One of the big hurdles was trying to figure out how to setup an efficient header and simple intake manifold setup seeing that there isn't much room for a header and most shelf intake manifolds for the K series would face a throttle body into the firewall. The initial kits offered an adapter to fit an F20C manifold. It was always my suggestion that the F20C manifold was decent enough to get the job done but might have been leaving some power on the table. We have been in search of some missing horsepower from chassis to chassis. We had a guess that we would lose some through the drivetrain over the native FF chassis but we were way down from where we should be. This is our attempt to find that power.







Here are our contenders. From left to right.

#1. F20C Intake Manifold with OEM 62mm TB
#2. Custom Excessive manifold using RBC runners mated to an Excessive plenum. You would have to contact Kmiata.com for info on this piece. (74mm TB)
#3. Custom Golden Eagle manifold setup to Kmiata specs. We moved the 74mm TB off the excessive onto this unit for the test
#4. Shelf Skunk2 Ultra manifold with 90mm TB.


Each manifold was tuned to the best of our ability using different style intakes for each setup. All on the same very cold day in a very cold dyno room.

#1. F20C Manifold - BASELINE TUNE




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This is how things started. 214whp and 180tq. Surprisingly the car was still fast at this power, but we knew there was more power hiding somewhere. For most with a Miata this is more than enough power. Most will need a good forced induction setup on their stock engines to reach this number and even then may not achieve a powerband like this.

#2. Custom Excessive manifold built for Kmiata.com



​Now we're getting somewhere. 225whp and 183tq while still not near where we should be, we are off to a great start. It was a major difference in the midrange needing as much as 12% more fuel and different VTC characteristics throughout.

Here is a comparison of the F20c and Excessive.


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#3. Skunk2 Ultra with 90mm TB


​Don't mind the RPM signal loss. Power was 230whp and 180tq. We didn't think this manifold would do very well given its size and hp nature. To our surprise it did very well with only a minor sacrifice in midrange over the Excessive but it carried the power up top very well.



Here is an overlay of the Skunk Ultra (blue) vs the Excessive (red)



#4. Golden Eagle Manifold ( Kmiata Spec)

and again we were having tach signal issues. The GE output 232whp and 183tq with the best overall output. We were very impressed with the fit, finish and powerband. It was our overall winner.




​Here is our comparison of the GE (blue) vs. Skunk2 (red). We are positive that with more compression, headflow and cam that the Ultra would definitely be able to flex its design but for a basic 2.4 the GE was very hard to beat.



Here is how the power started with the F20C manifold and how it ended up with the Golden Eagle. Given the space constraints of the header and limited manifold options I feel like we put the engine back on pace to where it should be. At the end of the day we are within about 4% of the power of where we were in the Integra. What isn't accounted for is that since the Integra was first tuned, it saw over 75 hours of track time and about 20,000+ miles of 8200 RPM abuse. This can also play a small factor in slight power loss over our original aimed goal but the engine still does seem extremely healthy.

Next up is a small header test that David of Kmiata will be doing to demonstrate the difference between a long and short tube header design. Keep an eye out for links and info on this test!


Thanks again to the staff at ProFunction for the help and David of Kmiata.com for the opportunity.
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crazyjetsfan22

iTrader: (5)

Thanks for sharing!

mixwell

awesome write-up!

redzcstandardhatch

Ooooooooooooooo

96accordsir

iTrader: (1)

awesome! funny how somebody has tested the skunk 2 ultra on a k swapped Miata already and I still have yet to see any b series all motor comparisons with it.

EsotericImage

iTrader: (8)

Nice thread!

good luck with it.

Curious to see how well the header testing compliments the IM

Samakhan

Awesome write up and results!

Andy Hollis

Glad to see you guys thawed out enough to do this test. Been anxiously waiting...

The other thing that will account for the difference between the Integra and the Miata with the same motor is driveline loss. RWD hits that much harder than does FWD.

I suspect the Excessive combo may have some inconsistency in individual cylinder filling, since the OE style runners come together quite closely for the merge with the plenum (RBC plenum is much shorter than the Excessive). The Excessive plenum narrows according to its much wider original runner spacing, so the volume does not taper down correctly.

MikeySpec

Thanks everyone. David was just as dedicated as I was to sit in a cold dyno room for hours on end to make this happen. I had the same feeling about the Excessive unit when I saw it. The idea is awesome but i'm not sure if the combo of TB placement vs. runner is doing itself any favors. Plenum volume definitely helped the midrange but it just couldn't hold its own up top. Its still a cool option and i'm just happy that there are actually options.

As for the drivetrain loss we were assuming about 3-5% would be lost through all of the shenanigans making the rear wheels drive vs. just having axles. Its no wonder that even with this mild power, David is raving about how well it drives now. Locally we have some time attack events and with some fresh arsenal the KMiata will be a contender in the RWD classes.

DDTECH

There's quite a few - Including My comparisons of a AFI vs the Ultra. Take the time to search, they may not be on Honda-tech however.. some are just on FB.


Mikey, As ALWAYS, Thank you for sharing..

Chef Andre

iTrader: (1)

Awesome!!!

Andy Hollis

How did the optimal VTC characteristics change as you moved from Excessive to Skunk2 to GE?

01DC4

iTrader: (3)

Well done as always mikey and dave!

blacK_Dc4

NICE! thanks for sharing

Pippen_001

Great job! Any pics of how the manifold fitments in the engine bay?

MikeySpec

Thanks bb

Mr. Hollis. The Excessive wanted the high VTC (our limit being 40) on the initial high cam hit but it wanted to taper down instantly. Where as the other manifolds behaved with a typical clean VTC drop just like any other normal manifold. According to the data it looks like we catered to an instant air surge that ran itself short on the high cam changeover with the excessive.

crazydominicanman

Great comparison thanks for sharing

crazydominicanman

Link to b series test ultra test? Would like to see the ultra cams vs the pro series and on the ultra mani