Re: the knife edges . . . .

Having a couple of AE degrees, I know that in subsonic flow, sharp leading edges are not desirable from a drag standpoint. Once you go supersonic, they are, but that doesn't apply to our engines. Look at a P-51 compared to an F-104 for instance.

So, I was just curious why we see knife edges on ported heads. I assume they've been shown to work better on a flow bench. Or maybe it's just a normal artifact of the porting process and no one has tried blunting the knife edge just a bit to see what it does. Or . . . ?? I dunno'.

Inquiring minds . . . .

ALLTHEFLOWS! I'm actually getting more and more disappointed that all I have access to is CA91 :sad2:

Now you people might understand why I keep pushing all the boost control and dual port EWG actuator threads. This shits going to be nuts.

I really ties the room together, man

Dooo eeet! ( In your build thread ;) )

God damn well better! That shits in October. OCTOBER! If my car is not running by October there is going to be a serious shitstorm up in here.

TBH I can't even walk right yet, I need to get that sorted before I can sign up for track days or seriously wrench on a car. I ahve some other more domestic automotive chores I need to handle as well that need to take priority. The wifes Escape needs new front pads, rotors and complete brake system flush and my DD Subaru needs a new clutch because wife can't handle the engagement on the Stage 2 thats in the car now. That's made things a bit hectic seeing as I can't drive a stick at the moment.

That's exactly why I made that comment and posted that pic, to start some dialog. We've all discussed this in the past and while I'm no ME/AE I have the same questions as well. Of course I trust that its done right and done that way for a reason, but dammed if I know why :)

Why no E85?

It's for weight reduction. :giggle:

Because the closest station with E85 is 56 miles away. Sacramento and San Jose are lousy with E85, even fucking Modesto has E85, but nothing in Monterey/Santa Cruz/San Benito counties :cry:

When you see me post up that I bought a set of ID1000's you'll know I have E85 in the area.

I need weight reduction more than the car needs weight reduction ;)

Has to do with Spec Miata rule that is OK to plunge cut to remove casting core mismatch, but not OK to P&P. Google for "miata compliant head". I'd attach a link, but when I try, phone crashes.

This had has absolutely nothing to do with Spec Miata. Did I miss something from Ricks comment?

Sorry, I misunderstood the subject.

No worries! I was really confused there for a bit. ;)

Anyone know of a good reason why I should NOT use the OEM head bolt washers with the ARP head studs?

Also, lol @ 80ft/lbs torque spec :facepalm:

Do they list 80 on the installation manual? That needs to be fixed. I wonder how many people have unknowingly cracked their heads.

Did your arp's not come with their own washers?
And anyone that has enough brains to go on MT knows better than 80lbs

FM has pics of destroyed heads on their site and we have 2-3 threads about ARP torque specs being insane.

Yes, the ARPs come with washers but factory washers are larger in OD than the ARP ones. I figure spreading out the clamping load at the washer cannot be a bad thing.

but is it the same strength/quality steel as the arp? (I'm guessing it's weaker, but that's just a guess)

My train wreck of thought is that the factory designed the washer and seat area of the head with that sized washer in mind, to distribute the clamp load over that part of the pad. The ARP washer is much smaller in diameter and thus will put the load in a smaller space. We already know the ARP torque spec is bubkis so why trust the washers?

We've all collectively discussed this in the head stud thread, but I don't know of anyone who actually did it. I was just looking for someone to talk me out of it :)

Do it. If anyone can break it, it will be you. Then we will know not to do it :)

do it
....for science

Thats the spirit!

Shits done, torqued to 58ft/lbs like a bauce :brain:

It feels soooooooooo gooooooooood to get that head on the block its just silly. I didn't take many pics because I was "in the zone" working and getting shit done. For the record I liberally wiped down the cylinders with some 30wt dino juice before bolting up the head so hopefully that keeps the rings happy. I also bolted up the intake manifold with the Hondata thermo insulator gasket that I think I bought literally 4 years ago. The nuts on the stupid manifold are pretty much impossible to get to once the engine is in the car, so now was the optimal time to get it done. They were installed with blue loctite. In fact, I went back through and pulled out the bolts for the oil pump and the water pump (one at a time) and reinstalled/retorqued them with a bit of blue loctite. I don't want this bastard coming apart unless I tell it to. I also installed the Denso IK16 plugs that were sitting in my tool box so now I can't drop things into the cylinders. They are gapped at 0.040 IIRC.

I don't often succumb to vanity but every once in a while... :party:

https://www.miataturbo.net/attachmen...1&d=1430012926

The NB2/MSM COPs are supposed to be good for what, 20psi? I need to order connectors to cleanup and rebuild that harness, its a mess.

I also started working on the revised neck to feed coolant to the turbo

https://www.miataturbo.net/attachmen...1&d=1430012926

This will need a blockoff plate fabricated, welded and then drilled/tapped for whatever fitting I end up using. Speaking of fittings, I also wanted to pull the return nipple off the mixing manifold and tap the hole for either M14x1.5 or 1/8"NPT and then adapt it to -6AN. I really like the Fragola M14x1.5 fittings I used on the turbo coolant ports and NPT is just "meh." I like the idea of using a minimal number of different fittings as well.

Anyone ever pulled one of these water nipple fittings out before? I'd like to do it without damaging the mixing manifold.

Yes. They come out pretty easily with a pair of pliers. I usually drill/tap for an NPT plug, but what you want to do would be pretty much the same.