Andy Hollis' One Lap Miata (K24 Honda power)
06-09-2015, 12:42 PM
#202
Link: https://www.miataturbo.net/build-thr...e3/#post709118. Designed to support ~200HP though -- isn't going to cut it for Andy. Cold air from the front of the car (headlight intake on my Red car) seems to work better. On the Silver car, I'd already cut the hole in the cowl, so I went ahead and re-used it.
I think Andy's diagnosis is spot-on. He's dumping tons of heat into the engine compartment with those big, snaking, uninsulated headers.
Andy, another thing to consider is that simple circular holes cut into sheet metal don't flow well because of the sharp edges. If you riveted some of these in, the radius should help the air get through:
ALUMINUM FLANGES FOR DUCTING from Aircraft Spruce
I think Andy's diagnosis is spot-on. He's dumping tons of heat into the engine compartment with those big, snaking, uninsulated headers.
Andy, another thing to consider is that simple circular holes cut into sheet metal don't flow well because of the sharp edges. If you riveted some of these in, the radius should help the air get through:
ALUMINUM FLANGES FOR DUCTING from Aircraft Spruce
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06-09-2015, 12:44 PM
#203
Danny Popp in a Lingenfelter-motored C5 Z06, and a handful of well-built Mitsubishi Evos.
The autocross and speed stop both have stage lines about five feet from the start line, which hands the AWD cars about a half a second advantage right off the bat. Hard to make that up. But the one Evo is super well-driven and engineered (same one which podiumed at One Lap this year).
I also got dicked on the engineering review and still have no clue as to why. Almost DFL on that segment.
Event Results
The autocross and speed stop both have stage lines about five feet from the start line, which hands the AWD cars about a half a second advantage right off the bat. Hard to make that up. But the one Evo is super well-driven and engineered (same one which podiumed at One Lap this year).
I also got dicked on the engineering review and still have no clue as to why. Almost DFL on that segment.
Event Results
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06-09-2015, 12:56 PM
#204
Cpt. Slow
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Sorry if I've missed it, but what clutch are you currently running?
We had plenty of people laugh at us during our recent enduro race when they noticed our complete lack of hood venting. It's a huge item at the top of our list of **** to do.
We had plenty of people laugh at us during our recent enduro race when they noticed our complete lack of hood venting. It's a huge item at the top of our list of **** to do.
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06-09-2015, 01:36 PM
#206
Have you considered copying the Randall Cowl Intake that Flyin Miata carries?
I was under the impression that it is the only one that really works.
I was under the impression that it is the only one that really works.
And, seriously, an intake sized for a 130HP motor on Andy's 300HP car?
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06-10-2015, 10:01 PM
#211
Andy is the belly pan under the engine in place? It needs to be there, it is part of extracting air from the engine compartment. The seal at the firewall to seal the hood helps too. Properly ducting to the rad is important as well, not only to cool the rad, but to direct the air in the right direction. These things need to be explored before venting the hood etc.
There are lots of threads about heat in MT forums.
There are lots of threads about heat in MT forums.
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06-10-2015, 10:08 PM
#212
SADFab Destructive Testing Engineer
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Here's the bastard child in all it's glory...followed by some of the mock-ups. Clearance between the release bearing slider tube and the clutch disc hub was still pretty tight, so I ground some off the top of the disc nub just for good measure. The flywheel is slightly recessed in the adapter, and when mocked up on the trans, pretty much the same clearance exists between the flywheel and the trans housing face that mates to the adapter. Which made me nervous. After assembly, I pulled the plugs and rotated the motor a bunch to verify no dragging sounds inside the bellhousing. A few odds and ends to put on the thing and then it goes in the hole. BTW, that's an Exedy Stage 2 cerametallic clutch. Same one I run on my CRX. Miata 1.8 pressure plates are weird...which makes the flywheels weird.... 
Last edited by IB Nolan; 03-09-2016 at 07:08 PM.
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07-07-2015, 11:59 PM
#216
Supporting Vendor
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ewsmotors -
I see what you're going for there, but the 0.5% theoretical gain in "ram air" loses twenty-fold to the massive flow loss created by the accordion hose.
edit: Emilio beat me to it
I see what you're going for there, but the 0.5% theoretical gain in "ram air" loses twenty-fold to the massive flow loss created by the accordion hose.
edit: Emilio beat me to it
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09-04-2015, 07:45 AM
#217
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Time to get this build moving again! Been playing with the CRX in NASA TT all summer, and just finished putting that one back into autocross trim for Solo Nats, so time to move back to the Miata. One Lap 2016 is only six months away!
Thanks for all the ideas, guys. In the end, I went with something proven to get the temps down, as this is how my CRX is plumbed. I'm headed to COTA tomorrow so I needed this done and effective.
Here's intake solution V3, achieved today. Cold air from the cavity behind the fascia, fed by the fog light hole and the slats in the wheelwell liner. I will fill the fog light hole when/if it gets driven in the rain.
The key enabler is use of 2001+ headlights, which use a later gen halogen bulb and have shorter housings. This exposes a hole in the chassis that Mazda later used for the Mazdaspeed Miata intercooler hose passage. A little die grinder action opened it up to 3" for our purposes, and we lined it with rubber to keep from digging into the thin intake tube. A Vibrant 180 U-Bend (#2869) was sliced in half and provided the perfect pair of bends to attach our K&N filter from the previous setup.
Big thanks to Keith Tanner at Flyin' Miata for the suggestion. Watching Craigslist, I scored this pair of working lamps from a partout for $100.
PS: I have not wired up the lights yet, but I have the pigtails so its just a matter of cut n' splice.
Thanks for all the ideas, guys. In the end, I went with something proven to get the temps down, as this is how my CRX is plumbed. I'm headed to COTA tomorrow so I needed this done and effective.
Here's intake solution V3, achieved today. Cold air from the cavity behind the fascia, fed by the fog light hole and the slats in the wheelwell liner. I will fill the fog light hole when/if it gets driven in the rain.
The key enabler is use of 2001+ headlights, which use a later gen halogen bulb and have shorter housings. This exposes a hole in the chassis that Mazda later used for the Mazdaspeed Miata intercooler hose passage. A little die grinder action opened it up to 3" for our purposes, and we lined it with rubber to keep from digging into the thin intake tube. A Vibrant 180 U-Bend (#2869) was sliced in half and provided the perfect pair of bends to attach our K&N filter from the previous setup.
Big thanks to Keith Tanner at Flyin' Miata for the suggestion. Watching Craigslist, I scored this pair of working lamps from a partout for $100.
PS: I have not wired up the lights yet, but I have the pigtails so its just a matter of cut n' splice.
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09-04-2015, 10:35 AM
#220
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The good motor (300hp) is a CNC-ported K20A2 head on a sleeved K24 block, forged internals, 13:1, with big Kelford cams. Runs on E85. It will rev to 9000, though I keep it limited to 8500 and usually shift at 8300.
The mock-up motor is just a simple bone stock internals 06 TSX K24A2 that makes about 250 on pump premium. Rev limited to 8000 due to stock internals.
Worked the car-center corner with a small hack saw and file. Also lopped off the outer thin tab of clear that sits just below the lens. And finally, I had to cut a couple thin support tabs off the back of the headlight assembly to clear the intake tube. Nothing major.
Last edited by AndyHollis; 09-04-2015 at 10:47 AM.
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