9k+ rpm on a stock n/a 13B?
 

I've been hearing people say that N/A 13Bs can be made to spin in excess of 10,000 rpm so that they can make more power without using turbos.

what does it take to get a motor to spin this fast and what holds a stock motor back (if anything) from doing this effectively?

just curious, any thoughts are welcome.

ummm 10,000 on a stock motor is just not possible. Not to mention how inefficient the stock engine would be at that rpm. These engines do have redlines and fuel cuts. While they do like higher rpm's that redline is there for a reason, and you aren't going to make much power after it. It takes quite a bit of modification to get an engine tio wind that high up, still be making power, and still be safe.

Yeah stock ports don't flow enough to have the engine operate at that RPM, plus the stock internals just wouldn't take it.

The problems that I keep hearing, when it comes to reving much beyond 8500 are four fold.

1) e-shaft flex can cause the rotors to contact the housings. I'm unsure exactly the conditions that cause this, but have heard this kicks in aroun 10000.
2) stationary gear deformation. This is the major reason that S5 13B's had a higher redline than S4, they hardened these. I know that at high rpms, the harmonics are what destroy these.
3)Apex seal float/chatter. This was one of the biggest issues mazda faced when bringing the rotary to life. Luckily they found a way to both decrease the amount of float and increase the rpm that this kicks in. This starts to become bad around 8.5k-9k.
4)Port and IM design are such that it doesn't really provide very much power past redline. Porting your motor can substantially push this 'falling off' much higher in the rpm, if its your hearts desire to rev high.

thanks i was just wondering but that was realy helpful guys

Andrew : Read the thread titled : "what is needed for 13k rpm" or something like that.

I`am sure your questions will be answered there!
Karis

I dissagree. I was talking to a mechanic who builds muscle cars and Can Am cars. He told me back in 80's he was given funds to research rotary engines. He went on to tell me that they could easily rev the mazda rotories up to 14k rpm all day. Ironically enough , it wasnt the apex seals that went, it was the ecentric shafts- theyt would snap. BTW, the shop is called Galant Racing, in Oakland/ Montclair, CA.

the important thing is there's no point - even with a stupendously large bridgeport, the power stops at ~11k.

$150 Fc : That is highly debateable.I have seen and heard a 12A that revs to 13K+.
It makes power untill 13000 and it lasts as well,a whole season of every 2 week racing,without being opened up!

No one has said anything about the water pump cavitation. Racing Beat says, the stock main pulley and water pump pulley can only run tp 6300 rpm, then cavitation starts and doesnt allow the water to circulate properly.Which doesnt matter as long as you dont hold it for extended periods of time. To fix the problem, just need to get a $50 smaller main pulley and you can hit 10,000 all day, unless you are talking about a 13b, then you would need racing apex seals which wont chatter like the heaving metal ones.

I think a lot of it depends on the motor. I know there have been people who have revved stock 12a's up to 10k by adding fuel and tuning them out a little more. My conclusion on this has always been that rotaries don't really have a 'redline', but more like a boom point. Redline has always been used with piston motors to designate the limit of the valvetrain and other internals.

On a rotary, as long as you have proper fuel you can rev them much more. When they rev out higher on the stock fuel they are spining higher RPMs, thus drawing in more air with the same amount of fuel. This leans them out. When you have added fuel there they are capable of spining higher, but to a point of course.

As everyone else mentioned, yes, there are limits to the stock internals, but they can be revved more as long as the proper fuel modifications are made, but as someone else pointed out, your powerband will fall off after 11k anyway.

I have personally seen stock 13b 4-ports revving up to 10k at the track and pulling high 13's or very low 14's.

so what sort of fuel modifications have to be made? is it just a matter of running higher octain fuel or physically feeding it more fuel? or NOS for the financially stable.
DAVE

You have to give it more fuel, pump, injectors, higher octane doesn't have much use in NA 7's.

one point that no-one has so far mentioned is this:

as great as it may be to be able to 10k+ rpm on your stock engine, they are NOT designed for this and it's not becuse they can't it's becuse everything else in your stock car can't.

Have you considered what your gearbox is going to do at 12,000 rpm it's not going to last very long at all.

i also question if your synchros will even let you shift your gears at that rpm.

and then you have your clutch your drive train and all the other stuff.

So even if you can get your stock 13b to be able to rev upto and beyond 10krpm i'd expect everything else is going to break before your engine goes pop.

I had an 84 GSL-SE and from 185,000 miles to 207,000 miles I spun it to 8k every day. 8500 fairly often and to 10k a couple times during tuning. With the Racing Beat Dellorto intake, exhaut and other items it ran a 14.38@93mph. It seemed to make power to around 8300rpm, which is where I shifted.

I acquired an S4 6pt and transferred all the RB parts over to it. Along with a bit of weight reduction and shifting it at 8500rpm, I ran a 13.96@97mph.

I am now running a street port 13B, all very old and used parts. 84 heavy rotating assembly and very old seals. I've tried to keep it to 9500 at a max (with the help of a rev limiter). Nothing special was done to the engine(just ported). I shift (and speedshift) at 9100-9300rpms and ran a 13.53@102 on street tires.

I'm not saying that this is the best way to go or that it will last forever, but in 20 years I have yet to hurt a stock engine while keeping it under 10k. If you want more power, there is always a tradeoff.

Some of you keep mentioning adding more fuel. Thats not what makes power in these engines. You have to have sufficient quantity of air.

The question is at what point does the rotor start traveling to fast to allow the port to stay open long enough to get the required quantity of fuel/air mixture in the engine and still make more power than the previous rpm segment? Now I don't know if this is a concern with our rotary engines but it could be. I imagine it will take someone capable of caluclating the amount of intake charge the time the port is open at a certain rpm to figure it out. Many variables involved but would be interesting to know. Anyone want to try?

Why would you want to spin the engine up THAT HIGH... I thought the purpose of making more power was to accelerate a car? And that rotational inertia goes up with the square of RPM? So all that mass attached to the engine (say 50-70lb of steel) takes twice as much energy to accelerate at 11000rpm as it does at 7800... now how much energy does it take to accelerate just the engine at that RPM level, figuring also that you need a higher RPM/second acceleration rate to make the same vehicle acceleration rate... at some point you will be losing net acceleration even though the HP number is physically higher.

You shouldn't be asking "How can I make it rev higher?"... the better question is "How can I make more power in my existing powerband" and "How can I make my car accelerate more quickly"....


- Pete (Three words: Proper peripheral port)

it doesnt matter how much power is being made at the rotor face or how much of that is being wasted. all that matters is that the net HP on the e-shaft keeps going up.

altough you make a good point about incresed force needed to spin an engine at high RPM you neglected that an engine can often be under static or near static load. in other words the rotational acceleartion will be very near zero. this is why a car with a lightend flywheel will feel practicaly zero difference at highway speeds, because the engine is undergoing very little roatational acceleration. once an object is spinning, whether that be at 750 or 12000 rpm no more force is eedet to maintain that rpm save countering friction which is largely independent of mass.

however, in a drag racing situation the engine is rapidly accelarting rotationaly so it is even more important for a high output/rpm N/A to have a lightned and balanced rotating assembly while it is not so important for a lower rpm turbo motor that achives the same net hp.

regardless, the weight of the parts will have no effect on a brake dyno which measures static load. the power will always be there and always have a chance to get to the wheels. the only question is how much of the engines power are you going to use to rapidly accelerate it along with the car. this is more a factor of gearing than the redline itself........

Sure. When you're running a steady speed, such as crusing down the highway at 25hp output. Or if you're pulling a trailer up a steep grade... but I don't think that is what we're concerned with. :) Likewise top speed running.... top speed isn't *racing* IMO, it's just sitting there like a lump with the throttle bolted to the floor.

When you're going down the dragstrip, you're concerned with acceleration.

When you're coming out of a corner on a road course, or the autox, you're concerned with acceleration.

firsl t, i want to shoot down all negative thoughts of high rpm engines... Formula engines spin like crazy... in excess of 17,000 rpm.
ok, i have given a lot of thought to creating a high rpm rotary, and I am more ambitious than andrew... i want a 20,000 RPM motor. Heres the parts list.

electric water pump
dry sump oil system-- high volume
extermal oil pump-- high volume
2 mfr oil coolers
big ass radiator
2 alternators(alternator rpms cut in half)
2~4lb rotors
one fuckin HUGE pp rotor housings
there that takes care of the engine

now for the drive line... we need to reduce the flywheel rmps a bit... so lets put a gear reduction before the flywheel, aft of the engine... say 2:1.. there the drivetrain is safe from excessive rpms, but now the transmission gearing is all off... so lets put in some custom gearing with dog teeth that can handle, oh... say 1000hp. oh yeah you might want to put a bigger rear end.

i figure with all of that, the speed each gear nets is ~85mph,

1st 85
2nd 170
3rd (maxspeed-170)/3 + 170
4th ((maxspeed-170)/3*2)+170
5th maxspeed

there it is kids...

Yeah, there's only a few problems with that. Keeping the eccentric shaft together at those RPMs, keeping the apex seals from chattering and grinding the housing away, where exactly to get rotors that are half as light as the ones Mazda came up with for their racing programs, keeping the stationary gears from deforming... and a big one, having enough port. You can't make a peripheral port big enough to flow enough air for 20k RPM. I sincerely doubt there's any combination of porting you can do to a 13B that will manage that. Oh, and gear reducing the flywheel... uh, why exactly? With a custom transmission it seems redundant. Finally, I have to wonder where exactly you came up with the speeds for the transmission... kind of... optimistic.

Oh, and holy thread resurrection, batman!

Have fun when your clutch flies apart and takes your legs off.

id have to say that is one of the bigger peices of talking out of one's ass ive seen in a while. dude it just isnt gona happen.

When you are talking formula engine, I assume you man formula 1 right? A formula 1 engine car can't really be compared to any other cars out there. Definatly not rotaries. Formula one uses very short stroke PISTON engines to get those revs, and even then the engines only last 1 race, sometimes not even that much.

I really want you to share the awsome shit you using, I don't think I ahve been f-ed up that much in my life dude.

And for all of you that want to find out about high reving engines, talk to the guys on Aus Rotary about some of those IPRA bridge engines, I think one guy is revving his engine up to 12,000RPM.

Hear hear!:beer:

the eccentric snaps at higher rpm due to the rotors trying to break it, right???---its not from just the eccentric shafts own inertia is it??....

it is a pipe dream, but im gonna try damnit =)

Actually, there's a rules change; the engines have to last the whole weekend. Testing, practice, qualifying, and the race. Needless to say, there's a few bugs that some people have to work out. Still, they're still going up to 18k-ish.



So actually, here's a funny thought I had on how to make a stupidly high-RPM rotary. Reliability levels would be... ah, well, plan on rebuilding after every race weekend. ;) Or maybe more often.

The big trick is that there'd be very very few parts that are as sold by Mazda.

Eccentric shaft flex is an issue. Well, have a multi-part eccentric shaft. Not only that, but a stationary gear on either side of the rotor... so for a two-rotor, we're talking 4 stationary gears. Also have the stationary and ring gears custom milled from... well, I'll just say "some exotic alloy" because that's simplest. :D Each rotor has oil fed to it independently of the other; dry sump of course. And since this is going to be rebuilt really often anyway, needle bearings used not only on the stationary gear bearings but on the rotor bearings.

Rotors are obviously going to have to be modified to have needle bearings and a second ring gear; starting from Renesis ones or something. See how much more material can come out at the same time, or maybe just make new ones from scratch. Making them from scratch might just be a better idea. Seals would be custom; 1-1.5mm, one piece (for reasons I'm getting to) and either carbon or ceramic. Longevity is a non-issue, so going this small can probably be gotten away with. They might have to be taller though... again for reasons I'm getting into.

Now... ports. There's a finite limit to how much port area you can get out of a peripheral port without forcing yourself to have inefficient port timing. This applies to intake and exhaust both, obviously. So you don't rely on peripheral ports alone. You combine the largest peripheral ports you can (say, to pull numbers out of thin air, leaving 5mm of rotor housing for the seals to ride on at the edge) with a "street" port on both the intake and exhaust side, like the Renesis exhaust. These ports leave *just* enough side housing for the seals to ride on; there's no limitations due to hitting water jackets, as the water jacket location is figured out after the ports are designed. Like I said before the seals might have to be taller... this is so they don't bend lengthwise and get chewed up by the peripheral ports. ;)

There's a few other details that I'm not bothering with, or that would come up in testing. This is just the more "revolutionary" stuff.

So what's all that get us? I honestly have no fucking clue how far that would spin, or what kind of power you could make. I don't think that it would be possible to spin it fast enough to start it at all with any normal starter... blocking off all but one side exhaust and intake port per rotor might do it, but I could see it needing something like a jet aircraft auxillary power unit to get it going (okay, that's also a funny mental image) It would *COST*... uh... well, lots. Anyone want to speculate how much it would cost to get... oh, just look at one part... a fully developed ceramic apex seal of vastly different dimensions than normal? And the fact that it would need to be rebuilt constantly is another factor.

But, hey, it's just an idea I had. Anyone want to fund it? :D

how about you start a machine shop and do all the work yourself? I am.

My first machine is going to be a fadel 20x40 vmc. So with that and some tooling im going to fug around with making performance parts for the rotory.

billet titanium rotors
custom pp sleves for max port area

custom intake manifold, so the pp would have low-mid and high end power.

A custom intake manifold (assuming you mean with variable length intake runners) does not make a HUGE difference, but it does help. It would just allow the engine to have "decent" low end power, but it would also limit the high end, but don't get me wrong that would still be amazing.

I read that stock Renesis were tested up to 17k rpm without issues. Also there are some tuners in Australia using Renesis E-shaft, rotors and fixed gears in regular 13B housings and reving them to 13,000 with no other mods except some porting and getting great results

Whered you read that? got any links, or the name of the publication?

hi-RPM
 

Mazda once did a display tes for the 13B, a stock moor was ran at full throtte, with no load, at 25,000 rpm (think of the stationary gear stress), the idea was to start it, stand back, and run it till it blows up.

The engine ran for 4 days and 4 nights, the project manager cancelled the project as it was consuming 2 much fuel...

Dont get me wrong, running an engine with a load is of course an entirely different game, but if it can rev that high (without an apex seal going through the side, or the eshaft going to bits), surely race engines could be built to go 20k rpm, even if they only last a race or 2.

Also my dad had a sock RX4, 12 a, went to 13000 RPMS easily when he was drag-racing his brother in law, who had a 327 powered v8 monaro.. guess who won..

the point is that 12A was still going 2 years later as a daily driver, and only broke down once when the fuel filter clogged...

holy crap, 25,000 rpm?? i love it.

good info!

spongey: not variable length, just more manifold being opened up... say three runners per pp. only one would open for low, two for mid and all three for high end power... get it?

I understand, very interesting.
I haven't heard of it implemented before on a rotary, have you?

nope never seen an intake setup like that before anywhere... have you? actually it has been implemented .. the rotating sleeves on the normally aspritated 2nd gens... mine is going to have butterfly valves actuated by solenoids, slamming them open and closed at different engine speed for max VE.

Well, aside from the bridgeport mill that we got in the fall... ;) Still working on getting that wired up though; we don't have 3-phase power.

Why don't I do all the work myself? Because I won't be able to make as good of seals as Ianetti unless I specialize in it and ditch the idea of making motors. Or I won't be able to make as good of stationary gears as a machine shop that does gears could unless I spend enough time specializing in it that I can't make motors.

As for your idea of narrowing port volume... the plumbing and fabrication on that gets tricky really fast. Toyota did do that idea with their TVIS setup, but it didn't work all that well.

The 2nd gens don't just change the port area, but also the timing. Don't forget about timing because it's a lot bigger factor than area.

Personally, I'm just building a peripheral port motor and living with the powerband not working at low RPM. And by low, I do mean low... look up data on peripheral port engines and see what the VE numbers are looking like across the whole band.

true race engine
 

A true racind engine would not follow the designs of mazda, but would be a true wrankel design, where the rotorts spin at the same speed as the eshaft... true rotart motion it was called

does anyone have any links to the designs for this?

I read somewhere that this design was concidered unusble for road cars, as to change the spark plugs u had to take apart the engine.. but for a true race engine who cares...

true race engine
 

A true racind engine would not follow the designs of mazda, but would be a true wrankel design, where the rotorts spin at the same speed as the eshaft... true rotart motion it was called

does anyone have any links to the designs for this?

I read somewhere that this design was concidered unusble for road cars, as to change the spark plugs u had to take apart the engine.. but for a true race engine who cares...

is that bridgeport mill a 2 1/2 axis cnc retrofit??? or just a handle turning mill?

(i've run both... once you go cnc, you wont look back to manual mills for production, except for maybe simple second operation)

what did you pay for it?? you can pick up a small 3 axis cnc mill for about 5 grand at auctions.

port timing is important, i forgot about that...so you're saying even the smallest pp couldn't possibly have good usable low end compareable to the n/a's??

might wanna learn to spell rotary before you make all these trick parts :rolleyes:

and i love all the misinformation being thrown about by 'my father's friend has a 50K rpm rotary'

projekt, :whogives: about spelling, i see where i mispelled rotary, sorry i was in the moment and didn't check my spelling. :p:

and oh yeah, stop exaggerating and elaborate a bit more.


.


:D

The bridgeport is hand-turned, yeah... nothing too fancy. We got it from a guy who runs a company in Michigan and had just finished converting over to all CNC stuff; we sold him all our MGA parts. The mill was $500; needs a little work and we need tools, but at *THAT* price.

Getting it home was a bitch and a half though... and no forklift at home to get it off the trailer. Heh heh...


As for the pp timing, that's not what I'm saying at all! I'm just saying that valving a peripheral port so that you can close parts of it for better low-end volumetric efficiency isn't simple. If you were trying to do something like that, a combination peripheral and side intake port might be best. The problem with peripheral ports isn't really even VE at low RPM, it's how they behave at part throttle / low load. So again, valved combination of side and peripheral have benefits.

Oh, I see what you're referring to; my comment at the end. Well, I *could* make a peripheral port motor that would work best at lowish RPM... but I don't really *want* to. :D I like the powerband of some of the MFR ports.

ooooh ic, i have a cool pp design that is going to rock! ........low, mid, and high end power.

ill ad you to my buddy list and show you some pics when i get them done... you gonna love it!

Hiya all,

Hate to say it Kenku but its been done and If I remember correctly talked about maybe on the old version of the forum.. but if not I am fairly sure Evil Aviator or myself may have posted about it in the past..
A Certain engine builder/Race car designer in St. Pete Florida.. (PM if you REALLY wanna know.. I just dont want them bugged) Has or HAD a engine that was in his hill climb car.. 4WD, 4WS based on a 13B.

The engine is based on a 1974 13B's Steel housings.. (IE:Largest 4-ports) with perif Rotor housings. The Primaries were healthy street ported.. the Secondaries are large Bridge.. and then there are the Perif housings.

THe intake was a tubular design that ran up to a progressive linkage 6 Barrel manifold for the custom Bosch fuel injection. The linkage was set up so that all the barrels were closed.. and the primaries open first.. then secondaries.. then terciaries(sp).. The 3rd set of barrels went to the PP housings..

The engine had the requisite high rpm treatment..

Locked Hardened rotor gears
C-Clip Bearings
Clearanced eccentric shaft
Dry Sump/modified high flow stock oil pump.. (Above I believe he said 9K the oil system goes into bypass even with the comp regulator and shim.. so he ran the oil pump off a shaft to a external pulley he changed till he got 110PSI at 14K rpm.. plus he did the dry sump.. and all the oil re-routing to make it oil correctly.
Oil Jets in the Apex groves (carb jets into milled holes below springs etc to allow metered oil to cool apex seals and lubricate them)
Carbon seals
They ran the oil to gas pre-mix at some silly amount I didnt really comprehend cause it was nearly half and half IIRC.. and it smoked resultantly like a badly tuned weed eater.. (More BTUs.. and More sealing in the combustion chamber=More Powah... just dont get too much and detonate)
14K redline
All this resulted in many wins in the Chimney rock hill climb.. and eventual exhaust restrictions to the point that it was soo choked that it was no-longer competitive.

The Idea is Out there.. FEW have done it.. It DOES make INSANE power.. If you have the savvy to pull it off. Better get a stand alone. he he he.. and have some time to play with that bridgeport..

Evil may have the pics of the engine more handy than I do.. as I would have to power up the server and sift through gobs of crap.. or find the original prints...(Plus I am at work ATM)

I myself PLAN to make one like that one of these days when I can justify making a engine that isnt legal in any racing.. :( And is only there to scare the street people.. he he he Right now just finishing building the EP engine..

Hiya all,

Hate to say it Kenku but its been done and If I remember correctly talked about maybe on the old version of the forum.. but if not I am fairly sure Evil Aviator or myself may have posted about it in the past..
A Certain engine builder/Race car designer in St. Pete Florida.. (PM if you REALLY wanna know.. I just dont want them bugged) Has or HAD a engine that was in his hill climb car.. 4WD, 4WS based on a 13B.

The engine is based on a 1974 13B's Steel housings.. (IE:Largest 4-ports) with perif Rotor housings. The Primaries were healthy street ported.. the Secondaries are large Bridge.. and then there are the Perif housings.

THe intake was a tubular design that ran up to a progressive linkage 6 Barrel manifold for the custom Bosch fuel injection. The linkage was set up so that all the barrels were closed.. and the primaries open first.. then secondaries.. then terciaries(sp).. The 3rd set of barrels went to the PP housings..

The engine had the requisite high rpm treatment..

Locked Hardened rotor gears
C-Clip Bearings
Clearanced eccentric shaft
Dry Sump/modified high flow stock oil pump.. (Above I believe he said 9K the oil system goes into bypass even with the comp regulator and shim.. so he ran the oil pump off a shaft to a external pulley he changed till he got 110PSI at 14K rpm.. plus he did the dry sump.. and all the oil re-routing to make it oil correctly.
Oil Jets in the Apex groves (carb jets into milled holes below springs etc to allow metered oil to cool apex seals and lubricate them)
Carbon seals
They ran the oil to gas pre-mix at some silly amount I didnt really comprehend cause it was nearly half and half IIRC.. and it smoked resultantly like a badly tuned weed eater.. (More BTUs.. and More sealing in the combustion chamber=More Powah... just dont get too much and detonate)
14K redline
All this resulted in many wins in the Chimney rock hill climb.. and eventual exhaust restrictions to the point that it was soo choked that it was no-longer competitive.

The Idea is Out there.. FEW have done it.. It DOES make INSANE power.. If you have the savvy to pull it off. Better get a stand alone. he he he.. and have some time to play with that bridgeport..

Evil may have the pics of the engine more handy than I do.. as I would have to power up the server and sift through gobs of crap.. or find the original prints...(Plus I am at work ATM)

I myself PLAN to make one like that one of these days when I can justify making a engine that isnt legal in any racing.. :( And is only there to scare the street people.. he he he Right now just finishing building the EP engine..

Well, that's getting there. :D That's really cool, I have to say... way out there. The idea I posted is wilder, but... a lot of custom fabrication, obviously, and a lot of R&D to get all the new parts working right.

I always love hearing about examples of people trying for the bleeding edge of what rotaries can do. 340hp (half of the 26B) for a 2-rotor is regarded by most as absolutely ridiculous, but I want to see that figure beaten... and not by a small margin!

You're right about legality for racing series though... but I have to wonder. Midwestern Council has almost no rules for building a rotary car in GT-1 as far as I can tell, and the weight breaks are such that in theory, maybe a 3-rotor car built to this ridiculous extreme could be competitive with the V8 boys. But that's Midwestern Council, and I'm willing to bet that SCCA has more restrictive rules. Only other place that comes to mind is NHRA or something.

Again, I have to make the disclaimer that I have no intention of making the "experiment in absurd RPMs" motor right now; just something that popped into my head.

That sounds pretty cool, and power across the whole RPM range is something to be sought for street motors. I started tinkering in my head with an idea to get something like that... modified 6 port side housings, and small pports, with a composite intake manifold made from scratch using lost-foam. Had all the runner lengths figured out, and ditto for internal geometries, but I came to the funny realization that I wanted to get the car running *SOON* so... shelving that and just going "conventional" pport.

Thinking about it, I did read a book that had some experimental port configurations that NSU tried. A couple of them had two different peripheral ports... one fairly simple one was just two circles one on top of another, but another was a circle surrounded by a larger semi-circle. I always wondered how you'd make a manifold for that one. ;)

the nsu wankel spider engines have 2 pp's. one teeny little port running right off the primary of the carb with really mild port timing. and then one larger port with more radical timing running off the secondary or the carb. the carb bolts right on the rotor housing.

something like that wouldnt be too hard to do at all

high rpm
 

There is a machinest here in WA that will make rotors to spin over 20K. He was on the LeMans team in 1980 (Bling ;)) . He said that the rotors are good for 30K but using a 93-95 crank 20K is limits. The rotors weigh 1/3 of stock. To tool his CNC right to make a set will run $60,000 and about $1K per rotor to machine. Friend 'o' mine is considering these for a SEMA car (what's the point, it's inside the engine??). As far as the flywheel & clutch giving up, thats' what balancing and scatter shields are for. If you're worried about porting and lack of fuel/air then put a hair-dryer (turbo) on the motor and force it in. Stand-alone can do almost anything these days. The same friend has a 13bt w/557 bhp at the wheels and a 10.5K redline (guess work) using a T78/tec3/Ionetti-seals/heavy porting in an 85 SE. All of this on a stock e-shaft but with treated stationarys. He hopes to run 11s or even 10s in a daily driver. We're waiting for the rear end to give (get a ford 8.8 or 9in).
Everything is possible if that money is right......
I have a 12a (stock) with a dellorto that i take to 9K daily with no troubles, however it will not idle with my jets and i get 11mpg.
That's my 2cent on the subject......

Dave

pip12434, what material are the cnc'd rotors?

60 grand? what in the hell for? programming?, but 1K per rotor sounds right...(too cheap even, if you consider the market-- racing beat sells stock "cnc" lightened rotors for about that price) http://www.racingbeat.com/resultset....rtNumber=10007


I am going to buy some round stock of grade 6 Ti, if that doesnt work i am going to use the proper grade of steel.

-mike