<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...

 

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.

 

Curb-hopping like a boss:

 

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?



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.