Keith Tanner said:
Simple volume.
Out of curiosity, and numbers you could share? What amazes me is how many different heads you can buy for a SBC. Surely if they are making *that* many of them, the Miata world could support 1 or 2 options? Or does it really not matter because most people would just boost then anyway?
I guess I'm fairly out of touch with old American V8s because I know almost nobody who has one/tinkers with it/races one/etc. Yet I feel like I know/see a gazillion people who modify Miatas. I know SBCs are super common, but just *how* common is modifying one like that? Or maybe they are just leftovers from the Pre-LS days when they were a lot more common?
In reply to ProDarwin :
They are leftovers from the pre LS days when everyone put a SBC in everything.
In reply to ProDarwin :
I think it helps that the OHV heads are quite a bit simpler to make. The machining is mostly about cutting the valve seats and the opposite side spring seats, and then the rocker mount. Then the 4 flat surfaces- intake, exhaust, block, and valve cover.
The lash area is either built into the rocker setup or in the camshaft area- so nothing special.
Vs. an OHC engine where you have to cut where the cam sits, and align bore it to a specific centerline above the block face, and then however the rocker system is laid out (rollder-finger-follower, direct buckets, etc)- and the oling paths of all of that.
So when you factor in the possible volume, it takes even more volume or higher costs to pay for an OHC set up.
In reply to alfadriver (Forum Supporter) :
And traditionally people who play with imports would rather spend money on strut tower bars and large exhaust tips than $2000 on a cylinder head.
There is another factor. Dart used to make blocks for Hondas when it looked like the tipping point was edging towards import parts profitability. The problem, besides the expense, was that the production quality was garbage compared to OE Honda parts. It is easy to sell aftermarket parts for Chevy because Chevy OE parts tended to be shoddy as far as casting quality, materials, and machining goes. So the bar to clear was pretty low. "Blueprinting" was a real need when OE machining usually left the decks wildly different front to rear, tolerances were all on the loose side to minimize production waste, etc. Not so with most import engines.
ProDarwin said:
Keith Tanner said:
Simple volume.
Out of curiosity, and numbers you could share? What amazes me is how many different heads you can buy for a SBC. Surely if they are making *that* many of them, the Miata world could support 1 or 2 options? Or does it really not matter because most people would just boost then anyway?
I guess I'm fairly out of touch with old American V8s because I know almost nobody who has one/tinkers with it/races one/etc. Yet I feel like I know/see a gazillion people who modify Miatas. I know SBCs are super common, but just *how* common is modifying one like that? Or maybe they are just leftovers from the Pre-LS days when they were a lot more common?
OE's kind of already addressed that. If you have an NA, the NB1 and NB2 heads bolt on and flow better (though admittedly they still aren't amazing).
I think another issue with heads is that a LOT of them that are modified and raced do so under a rule set. SBC and even Hondas were the wild west. I'm sure that Keith can point out that they sell a bunch of turbos and what not that are just for street cars where rules don't matter, but 95% of the Miata people I know live and die by the rules and only consider parts that fit within whatever rule set they're playing under.
In reply to ProDarwin :
Keep in mind General Motors produced their 100 millionth sbc v8 in 2011. That's not counting all the aftermarket blocks and parts made outside of gm. 100 million. How many Miata's have been built?
AnthonyGS (Forum Supporter) said:
Keith Tanner said:
AnthonyGS (Forum Supporter) said:
Keith Tanner said:
The problem is that everyone reads on the internet that 250 is fairly easy and repeatable, so they call and ask for 300 because, well, who wants what everyone else has? It's been going on for 15 years :)
300 rwhp was a magic number at the beginning of the 21st century. LS1s did it so easily everyone wanted that number. I had Mustangs back then and everyone was gunning for it. I also had a Miata and everyone was trying to boost their way there. Few in either camp made it. The easiest way was and probably still is sell what you have and go LS. Heck 996 and 986 P cars are pretty light but the amount of whining about 300 rwhp would make you think an LS swap is the only answer there too.
Correction, it's been going on for nearly 20 years. Man, I've been doing this for a while.
I'd ask people "why 300?" and invariably they'd tell me "because everyone has 250". LS engines were never mentioned, it was always just to have a slightly bigger hootus than the other Miata owners.
About 12 years ago the LS Miatas really came on the scene and we had a rapid escalation of power availability.
I agree it really is an arbitrary number and no idea why everyone thinks it's the magic number. I prefer a car that is fast but can be enjoyed, driven in traffic, driven at the track when time permits. A lot of high hp setups do not do this. They are one trick pony's. I like a wide useable power band. I'm willing to give up max power in order to get a broad torque curve. But I'm an oddball, I know that.
I have had a lot of customers go with the more is more philosophy, and upgrade their cars to the point they were no longer fun to drive.
I spent a while detuning cars for better livability - bushings where rod ends were, quieter exhausts. Usually though they sold the monster and bought something more pleasant.
bobzilla said:
In reply to ProDarwin :
Keep in mind General Motors produced their 100 millionth sbc v8 in 2011. That's not counting all the aftermarket blocks and parts made outside of gm. 100 million. How many Miata's have been built?
They stopped making the "SBC" in 2002 or so, no?
The LS is a SBC the same way an Ecoboost is an F2T. One led to the other but they share nothing but some incidental dimensions.
Some argue that the last SBC was in 1985, and LT1s are right out.
In reply to Pete. (l33t FS) :
They manufactured the old school sbc for medium duty trucks through 2010(?) and are still manufacturing them for industrial use (generators, mobil equipment etc). 1985 is such an odd date to pick. They didn't switch to one piece rear mains until 87 and center bolt valve covers were the same time. LT1's were unique and only used in cars. Truck sbc were pretty much unchanged from the 1955 versions mechanically through 1998. The thing that made a sbc a sbc is the exhaust port arrangement, cam placement, distributor in the rear was pretty much the same. Yes there are differences. Displacement has changed, Head design and flow. Intakes, induction, distributor changed. But to say a vortec 5.7 isn't a sbc is just silly as hell
In reply to bobzilla :
That is interesting, did not know about the generators.
One piece seals and tall cylinder head castings are Not Real SBCs to some people. And let's not mention when they switched the dipstick to the other side of the engine, or put accessory holes on the ends of the heads!
AKA "It's different than what I grew up with therefore it sucks"
In reply to mazdeuce - Seth :
You are right Seth. I have a $2500 Spec Miata head on my miata. Not that I paid for it but it came with the car. I know the builder and he was one of the best so I love the fact I have it. Now is it the best/cheapest way to make HP. Not on your life. But if you are running Spec miata...It's one of the best. That's the world most miata owners live in.
Mazda has made just over 1 million Miatas with three distinct engine families - and of one of those families, there are two incompatible blocks. So anyone looking to bring a custom head to market is dealing with a very small potential customer base. As Alfa pointed out, it's not a simple OHV casting, either. It's not just the complexity, though. We had a stroker kit with a long throw crank and custom rods, etc. The crank alone cost us close to 10x what Summit gets for a random SBC stroker crank.
If you wanted to make money with aftermarket heads and intakes and blocks, you'd be doing it for Hondas because the volume is so much higher - but it's really hard to improve on Honda parts. You can argue whether GM made 100 million small blocks by 2011 or whether the LS doesn't count or whatever, but it's pretty clear that you're still talking about a couple of orders of magnitude difference.
Also, the import world discovered boost at least a decade before the V8 guys realized that it was a thing. And boost is a lot easier than rebuilding an engine. It's a lot cheaper and simpler to stick a hair dryer on the side of a block than it is to deal with a DOHC head swap - just think of how many times we've had the "I've just done a timing belt and does this cam timing look right to you?" conversation on this forum.
mazdeuce - Seth said:
I think another issue with heads is that a LOT of them that are modified and raced do so under a rule set. SBC and even Hondas were the wild west. I'm sure that Keith can point out that they sell a bunch of turbos and what not that are just for street cars where rules don't matter, but 95% of the Miata people I know live and die by the rules and only consider parts that fit within whatever rule set they're playing under.
I think that's more a reflection of the people you hang out with. There are a lot of modified street Miatas out there that aren't built to a rule set. We sell more turbos every year than there are Global Cup Cars in existence, and we've been doing that for decades. Spec Miata is an insanely popular class but it's just a tiny percentage of the number of Miatas out there.
Agreed on the boost. I suppose a lot of people just want to go fast, and they don't care so much how they get there. And even a very tame boost setup is going to have greater returns than a better flowing top end. Those that want to go fast within a ruleset don't have swapping heads as an option anyway (or some silly autocrosser would probably have CNC cut his own head by now 
)
I guess I was thinking about it from the standpoint of the search for reliable trackday power. It seems that lot of the allure of a K swap is that you can hammer a >200whp the track all day and not worry about underhood temps/stuff like that, whereas it seems that when you are in the 200-250whp via boost range there are all kinds of issues that pop up and making that system reliable is difficult. That's also one of the selling points of the rotrex setup. But maybe this is blown out of proportion?
For the people in the above camp I would imagine if a $2500 engine build to get to 200whp were an option it would be pretty desirable.
The biggest problem with boost on track is that it's too easy to make more power. So people keep turning it up until they get to the point of unreliability. Give yourself some margin and exercise some mechanical empathy and you'd be amazed at how much more reliable everything is. Sure, you might be a second or two slower, but you'll still be lapping when the fast guy is wrenching. We've been tracking turbo Miatas at FM for years and years and the failure rate is quite low. We don't "win" track days but we have a lot of fun and make a lot of passengers happy.
Underhood temps aren't really a problem. Coolant temps do need to be monitored, as any sort of boost will involve an extra heat exchanger in the nose along with more heat from the higher power output. This again comes down to that mechanical empathy thing and giving some margin. On a turbo Miata, for example, shifting at 6500 instead of 7300 will have a big effect on your coolant temps. Won't slow you down all that much, either.
You can take a Mazdaspeed Miata to 200 rwhp with our "little Enchilada" kit for your price range. And it's been VERY popular over the years. That's just a matter of removing the factory roadblocks, you have to start with a turbo. Starting with an early Miata and expecting to easily bolt on nearly 100% more power for $2500? Yeah, that would be nice.
In reply to Keith Tanner :
Interesting on the RPM. That sounds like something rotary racers have to deal with since the stock pulley/pump areangement stalls at 6000-7000rpm depending on model. Underdrive pullies fix this. Do underdrive pullies exist for the BP or do most people just figure on keeping the revs down?
In reply to Keith Tanner :
I actually typed out my whole post and read it and went back and changed it to reflect the fact that I was pretty certain you would tell me I'm wrong and hang out with too many track/AX people.
I wouldn't bother with a modified naturally aspirated Miata on the street unless I had to, I'm kind of a fan of those spinny things you guys sell.
Pete. (l33t FS) said:
In reply to Keith Tanner :
Interesting on the RPM. That sounds like something rotary racers have to deal with since the stock pulley/pump areangement stalls at 6000-7000rpm depending on model. Underdrive pullies fix this. Do underdrive pullies exist for the BP or do most people just figure on keeping the revs down?
Underdrive pullies for the crank exist, and they ensure you'll never have to change the oil on a turbo Miata again because the oil pump won't survive long enough :) Underdrive pullies for the water pump exist, I believe, but are surprisingly uncommon.
Naturally aspirated street Miatas can be fun, but you definitely have to be in the mood to play to access the performance.
In reply to Keith Tanner :
Good to know. I am not as up on the performance aftermarket for BPs as I would like to be. Surely it does seem to be easier to turn up the boost knob another notch than try to get another 700rpm. (Because more, right?)
I have a pet theory that we are seeing more electric water pumps so they can get max cooling flow when the engine hits 20psi at 1500rpm or whatever these modern wondermotors do, without cavitating before redline or otherwise drawing too much power when not needed.
