BP head porting intel from the pros
 

https://www.miataturbo.net/attachmen...ine=1337704185

Had an insightful visit at Keegan Engineering, where the boss dropped knowledge on how they port their BP heads. It is possible that they've forgotten more about porting than most people ever knew.

All the words are here. Some numbers, too.

"Also, he's found that the VVT heads are generally much better from the factory than the early NB or NA heads in terms of casting quality and core shift. The early heads often have a 0.040-0.050" step where the port meets the valve seat that the factory doesn't bother to clean up.

As if you needed another reason to use a VVT head on your Miata hot rod."

that intake port looks so much better than mine after working on it...

That is good info!!

Some I knew and do, some I didnt and learned.

I'm impressed! I'll be porting my own head soon enough so this is relevant to my interests.

:drool: What would a lowly pleeb such as myself expect to pay Keegan Engineering for such masterful service?

Excellent post, I've enjoyed reading these updates!

/\ THAT :drool:

Just a guess... Spending 15 hours to port is going to cost, figure $50-75 /hr then add in the valve job, surfacing and any other machine work and parts.

J j j JKAV IS GOD


ok big question. Does all that velocity advantage stuff matter if you are boosting? For boost dont you just want max flow?

Yikes! I've got a VVT head sitting in the garage mocking me, but that's $750 on the LOW end, just for port work. That's like, an entire new Supertech valvetrain. It's sexy, but not in MY budget. :cry:

But wait!
Now THIS is something I could get behind. I understand that hand-porting will almost always be superior to CNC, but for outright cost, this has always looked like the way to go (other than DIY.) I honestly would have no issues sending a head to KE and having a service like this performed.

I'll be watching this closely.

One thing that became very apparent is that if you don't know what you're doing when porting, it's easy to end up worse off than if you left it stock. I'm all for DIY and experimentation (have you seen my lemons car?). But head work is like valving shocks - best left to the pros, in my opinion.

EO2K, Keegan will work to the customer's budget and needs, suggest dropping them a line - 562.301.3277, info@keeganengineering.com. Mike's super friendly.

Faeflora, it is true that boost provides a nice dose of port velocity. If you had a land speed record car or drag car you might get by with an oversized "dead" port because you'd be in boost all the time. For a boosted track car or anything that involves part throttle modulations and transients, you want your ports to have inherent velocity and flowicity (I might have just made that word up).

Curious. I would have expected blunt leading edges on the intake ports. I can't tell though from the head-on picture if it might be.

Are you talking the point between valves? They are sharpened on my cyl head as well. I would have to assume having them sharp maintains speed. It is what I see on most ported heads.

Awesome, thanks for sharing.

Yes that. I read the Inside Line blog entry and he does indeed keep the leading edges blunt on the intake side.

The reason I asked is because I read elsewhere that some engine builders dont like sharp edges. Their justification was not the same as Keegan's. Keegan says thin edges crack. Other builders (I can't remmeber who now) say that subsonic flow leading edges are always blunt.. like any aero body would be and that you would only see benefits from a leading knife edge as you start to get into supersonic flow.

Or something to that effect.

Trailing edges, as you have on the exhaust ports, are another story. Sharpness there makes aerodynamic sense. But maybe not strength sense.

Anyway I was noticing in the photos after looking closer that the edge profile is probably not a big issue since it's significantly narrower than the projected area of the center wall and the bluntness is likely a miniscule contributor to drag around that wall.

I took a look at my head, and they are sharper than stock, but do indeed have a somewhat blunt edge. I would say similar to the OP's pic. The exhaust side seems to visually have a similar edge.

Its for off boost throttle response.

For a street driven car, its nice to have.


To me,what would be the best is have the head casting CNC ported, to get all the proper locations and sizes set, then have the CNC port work hand blended so it is clean and smooth.

Both CNC port and hand port have there pros and cons.

It is a bit of an optical delusion. The port divider/septum on this head is fairly blunt, esp in the saddle point. Definitely not sharp, anyway.

Not sharper than factory?

I have studied in aeronautics and worked in a machine shop where we ported heads by hand and with a 5-axis CNC machine, and I can tell you that for intake ports, you definitively want to have a blunt transition between the two runners, because it reduces the boundary layer's height (http://en.wikipedia.org/wiki/Boundary_layer) and turbulance, which is not characteristics you want in your runners. Picture an airplane's wing leading edge (http://en.wikipedia.org/wiki/Leading_edge), it is not sharp for the same reason.

Isn't that kinda what I said?

Yup just clarifying no worries.

Thanks Jason, I'll do just that here in a bit, once I get a little more "cash positive."

Did the boys over at KE touch anything on the intake manifold? Port match or anything?

No, nothing done to the manifold yet.

Thanks for posting this! I did some of these mods (round off straight edges in combustion chamber, valve port ridge removal and remove machined edges by valves in combustion chamber). I'm glad to see they are justified.

:rly:

FWIW, Keegan has been building our engines for a few years now.

- T25 win
- More than a dozen enduro wins
- More than a dozen NASA PT race wins
- Lap records at three tracks in two classes

You could say we're happy customers.

I always thought it was the shocks, lol.

That we seem to be able to tune the Miatas handling for a given track, conditions and race strategy better than anyone else may be a contributing factor ;)

Just the same, Mike Keegan has proven amenable to experimentation and communicates with us very well. We kick ideas around for various projects.

It goes something like this:

Me:
"Hey Mike, I want to try these nine hare brained ideas."

Mike:
Yeah, um three of those will make power in a Miata engine."

Me:
"Make it so."

When I go to work every day I get to do things like complain about forms, politics, and deal with people who use paper instead of computers...you get to do things like this.

correct me if I'm wrong here, but:
you are unmarried
have no children
you are not a property owner

what the fcuk is stopping you?

You're telling me to make an offer to 949 that they cannot refuse?

Actually I'm waiting on my GF to finish college so I can re-educate myself and start over as a business owner.

I almost moved to TX to work at BEGi. and by almost, I talked to Corky, and looked at how much plane tickets would cost to fly me and my wife out over a random weekend last summer.

acutally, if they were closer to austin over sa, it probably would of happened, but there was nothing for my wife in SA, but lots of crap in austin.

No I'm not saying that at all.

I'm saying start hustlerspeed. start your own deal. like emilio did.

I'm not an engineer.

But you play one on mt.net!

You don't need to be. Most of the shop owners I know pay the guys who do the design or fabrication work and don't do it themselves. Much of it is proper marketing. There are local shops that make lots of money doing mediocre or poor work because of good marketing. Their shops are full. Some of the best fab and design shops close because of poor management or marketing, not because the work is shoddy or the designs are ineffective.

Long story short, I would likely put a "Hustler Racing" decal on my car even if all you made was decals. If it was an attractive decal...

https://www.miataturbo.net/attachmen...ine=1340313870

Latest installment details the Supertech valvetrain that's going into this head - valves, springs, retainers, shim under bucket...

All the words are here: http://blogs.insideline.com/roadtest...rain-tech.html

any info on the cams specs? I'm sending mine off to get custom ground by Web here in the upcoming weeks. no specs set in stone, yet.

In a few years I'll have a Mech Degree. I'll work for ya Hustler. Prior Military so if the Zombies come I could be an asset. Wife is in school for the finer side of chef so you could be well fed. I already learn from you via your threads. I always have odd ideas that probably won't work. A little bit of explosives training, couldn't hurt. Plus I like a good drink here and there (Bud Light is pee). My only downside is I have lost faith in man kind and I work a little on the slow side due to being a bit methodical and ---- retentive. But done right once is better than wrong twice.

Interesting to see that you got the same wavy surface on the retainers as I got (so the quality seems to be consistent).

I've rejected the ST retainers due to poor fit on the springs and the 15-20 hours inspection intervals (they failed catastrophically due to wear after 30 race hours in a BMW head).
I'll use retainers in billet steel instead (much better wear resistance and custom made to snap-fit the springs).

https://www.miataturbo.net/attachmen...ine=1344986203

Some deets on the actual build process. No joke, Keegan assembles and disassembles the engine at least three times before building it for real. It's really something to behold.

1997 Mazda MX-5 Miata: Assembly By Keegan Engineering, Pt. I

Can Keegan make a miata head flow well enough to hit 700hp at something other than 60psi?

fae, stop right there.

Serious question actually. I love JKav and I would trust him with my frozen embryos and this thread makes me feel stupid and that's a good thing.

My question is really, has Keegan built any miata heads specifically for boost?

I will give him a call, but I am asking for anectotes first.

Post back with what you find out if you don't mind! I have an engine I will be building later this year and am debating sending the head off to him for a little love. The '99 head I will be using already has oversized FM valvles and some of intergral's old 272 cams. (its for a rotrex build.. shh don't tell no ones!)

Remember when NA builds didn't make sense so we all built turbo Miatas? Well, it looks like those days are over.

Nah, time have just evolved so a Turbo build should now only be done on built engine and should deliver 350+whp. If not, whats the point :D

If everything goes the right way (and then some) I'll have my engine in three weeks (or it will be yet another race with the trusted old 70+ race engine).

I still don't see the point in N/A builds unless track car

Good question, I'm really not sure of the answer as it pertains to Miatas specifically but I never asked. I do know that at Cosworth he used to port the IRL heads and built their ChampCar engines back in the boosted days. Suggest dropping him a line.

This will be turbo.

JKav,

Great project, been following the car since it started on Insideline and saw it out at Buttonwillow with Kurt driving it a few months ago.

You should have the car out at Buttonwillow again next month at the Speedventures weekend (09/22 - 09/23). Miata Challenge will be there and it's going to be a ton of fun. Would love to see you guys running it.

Anyways, keep it coming.

Thanks comradefks. In that case...

http://blogs.insideline.com/roadtest...ting-rods.html

edit: seems our site is having some issues right now... try the link later.