<p></p><p>Asking MT.net to stay on topic is like telling a fat kid not to eat cake...not gonna happen.</p>

There's cake?

I hope its chocolate...

Somebody said cake. I'm in.

<p>First mobius donuts, now andys cake thread. We're all fatboys.</p>

Those ITB's ended up here.

Ok, back on topic...

Cold-air intake, version 1: cowl-fed.

2x2" holes in the cowl feeding coroplast sealed intake chamber.

Looks pretty good, but datalogger results say...Fail. 146 degrees IAT after a couple of laps.

Back to the drawing board...

https://www.miataturbo.net/attachmen...ine=1433807800

Took the car for its first competition outing...Optima Ultimate Street Car Challenge at NCM Motorsports Park. Managed 4 th in the autocross and 6th in the track competition in the fastest class. Learned a bunch about the setup.

Big items to solve ASAP:

1) Do something about underhood temps. Need to install the double-ceramic-coated headers and vent the hood.

2) Need better cold-air intake setup. This one was delivering IAT's of 146, killing lots of power.

3) Clutch is slipping after about 4 hard laps on the 4-5 shift only (other shifts are fine). Granny shifting will save it sorta...but it's a problem. Not sure if heat -related (downppe is right next to clutch housing) or simply insufficient pressure plate clamping,

4) Once the car is really hot, the throttle likes to hang partially open...about 4K rpm idle worth.

https://www.miataturbo.net/attachmen...ine=1433807844

Curb-hopping like a boss:
https://www.miataturbo.net/attachmen...ine=1433809687

Nice chatting with you at NCM and congrats on a strong showing against all those super cars!

Cheers

I'm curious what other types of cars were in your class?

As am I. No aero and still dialing it in, and 6th place? What beat you?

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

Probably didnt have an optima battery and parts from the rest of the sponsors. Or so I've heard thats the trick.

Have you considered copying the Randall Cowl Intake that Flyin Miata carries?

https://www.miataturbo.net/attachmen...ine=1433820537

I was under the impression that it is the only one that really works.

Looking good as always Andy. I'm curious what you come up with for the intake. You know, so I can steal your idea....

Hornetball has an awesome cowl intake. I believe its somewhere in his silver car build thread.

What's the pressure difference between the wheel well and the cowl?

I get decent temps (measured at the filter) by dividing the engine bay with coroplast and getting air from the wheels (no inner fenders).
But I have a RB header and make less power.

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

Any idea why? That's contrary to popular Miata wisdom regarding cowl fed intakes.

vs.

:giggle:

Also, while the cowl is supposed to be a positive pressure area- Has anyone actually tested the extreme edge of the cowl? Having walls on two sides in that spot might produce a deadzone.

I noticed that in the results and thought that category was a little silly.

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 shit to do.

You owe me a picture. :party:

LOL at a Randall cowl intake on a late NB. The factory CAI is probably more effective. You'll notice that the "dyno" Flyin' Miata uses to sell these was from an early 1.6 car (no factory CAI). Buyer beware.

And, seriously, an intake sized for a 130HP motor on Andy's 300HP car?

<p>Curly are you going to be running one of&nbsp;hummings vents too?</p>

I'm gonna cut some stuff at cost for Curly and GreddyGalant's enduro miata. :party:

Iknowright? I'm considering air sources in my build now and was contemplating an "NB" style hole below the headlight, fed from the fender and the boxing that area in to feed the filter. Perhaps that's the source to try next?

Any idea why? Even the factory shielded the exhaust at their power levels.

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.

That's nice.

https://www.miataturbo.net/attachmen...ine=1436312032
Hi Andy,

Your car already has fog light holes, I suggest trying a system similar to this one on your K Miata:



https://www.miataturbo.net/attachmen...ine=1436312032

https://cimg9.ibsrv.net/gimg/www.mia...c3affdeb0f.jpg

That would be a bad idea for a few reasons

1. Your system will soak the filter when it rains
2. Those corrugated hoses flow approximately as much as a soda straw
3. Why use two intake when one will do
4. What Andy has is already really efficient

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

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.

https://www.miataturbo.net/attachmen...ine=1441367101

https://www.miataturbo.net/attachmen...ine=1441367101

https://www.miataturbo.net/attachmen...ine=1441367101

https://www.miataturbo.net/attachmen...ine=1441367101

Shit, this is baller; wish I saw earlier. Any reason you didn't want to run a K20A2 head for a hybrid setup?

Have you cut the front bumper to make them fit? Interested in seeing how you do it.

Because I am?

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.

Yes.

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.

<p>Post pics of it finished? I can still do this... still have my MSM lights.</p>

The third one earlier is finished from the back. The front is nothing special. Plenty of people have swapped headlights. Miata.net is full of 'em.

Oh, and do your homework. Apparently there is something different about the MSM headlights versus the "normal" 2001+ lights.

PS: yes, the hood is VERY dusty. Been sitting a long time...

https://www.miataturbo.net/attachmen...ine=1441387406

But I'm scared of Miata.net.
More homework to be done. Thanks for posting the pics though. Looks pretty good.

Welp, I missed that. It's going to be a hilarious drive.

It already is. In fact, I just got back from another drive in it.

Going to COTA with it tomorrow.

Today's fun...

https://www.miataturbo.net/attachmen...ine=1441496447

Video:

Dude . . . we need IN-CAR video!

I posted the wiring diagram and mods for the headlight swap in my build thread. I made brackets to hold the bumper cover closer to the headlight housing. The wiring diagram will also allow to use all four bulbs when using the high beams.

https://www.miataturbo.net/build-thr...-62620/page26/

https://www.miataturbo.net/attachmen...209_210314.jpg

Wrap that thing

So Andy where do AIT's ends up with your new intake setup ?

Sub'd

Back to work on this.

Wired up the IAT sensor in proper position last week, so I can now answer this question. Basically, I get IAT's just a few degrees above ambient if the vehicle is moving. If it sits in traffic for awhile, it can go up 10-15 degrees as the intake heat soaks, but it goes right back down again once in motion and fresh air bathes the sensor.

Some hood venting will fix the soak problem...

Andy,

Where did you move the IAT? and where was it originally?
I'm currently planning on using stock s2000 IAT and same location, do you think I should move the IAT to the Intake piping?

Here is my current location of the sensor.
https://www.miataturbo.net/attachmen...ine=1447044101

Leave it there.

In theory, IAT in the manifold is actually closer to what the engine sees anyway.

Mine had been hanging in the engine bay near that cowl opening because the harness did not have enough wire in it to get to the intake piping. Now its where it belongs in the actual intake stream. I suppose I could have drilled another hole in the manifold and installed it there next to the MAP sensor, but that would have required removing the manifold.

In other news, the Miata is now as quick on track as my CRX. That was a huge milestone and confirms the platform change motivation. Still not as consistent, as I'm having trouble getting all the power down even in 3rd gear coming off corners. 225 Rival-S on 9's can't handle 300hp in 3rd unless you are perfectly straight. And I am going through rear tires at a prodigious rate as a result. On r-comps, the solution would be a no-brainer...but One Lap rules say 200tw.

So...time to do "what they say can't be done".

"What can't be done"

Got my interest

Any plans to test the 245 width Maxxis VR-1?

Unless the sensor can heatsoak, like the GM one*

*I know nothing about s2000 AIT sensors. For all I know heat soak may not be an issue

Yes.

But I don't expect that to be my final answer. Given what Emilio was saying publicly (VR-1 = AD08R performance), it would likely deliver performance on par with the smaller Rival-S but last longer. I want both faster and better wear. Still worth testing, though.

We are at an interesting time where the fastest 200tw street tires can deliver a couple fast laps similar to a streetable track day tire (e.g. NT01, R888, RA1, RC1), but then fall off. But they don't last anywhere near as long as those track day tires. They are essentially rules-beaters for autocross and time trials. Similar to the difference between Hoosier A7 and R7, though at a lower performance level.

The previous crop of 200tw tires delivered both long life and consistent performance for whole sessions. Perfect for crapcan racing and budget track days...not to mention dual-purpose daily use.

Size also plays a factor when dealing with the whole 23" tall tire deal. In the last GRM track test, we found that a 205 RE71R was faster than a 205 Rival-S, but a 225 Rival-S trumped all.

I smell another tire testing article...

I think the current 200tw group are the epitome of the perfect STREET tire. Long wear when they are cold/warm, wacky grip when they are hot. Far improved from the last group for true street cars.

I also saw none of the drop-off you talk about in the Rival S, even over long enduro stints (2hr).