Sydneykid

For circuit racing I ask the tyre engineer what effective spring rates his tyre likes. After all that’s the point of contract with the road and optimising tyre traction is what it’s all about. In a RWD car I use that as my target front effective spring rate, then let the weight distribution of the car tell me what effective spring rate is needed in the rear. Note the term "effective spring rate" that is the actual spring rate divided by the movement ratio and then the leverage ratio. The tyre only feels the effective spring rate, it doesn't care what the actual spring rate is. For a tarmac road event, using the same tyres, I would come down in spring rate in comparison to what I would run on the track as the average road surface tends not to be as well looked after as the track. Plus we have to be aware of the possibility of rain if its a long event like Targa Tas. Somewhere between 10% and 20% lower has worked for me in the past. Cheers Gary

Yamaha specifically bought Ohlins for their motorcycle shock technology, so it's not surprising that the Ohlins branded car shocks that come out of the Yamaha factory in Japan are similae style to the Ohlins motorcycle shocks. I haven’t directly compared the Japanese Ohlins motorcycle shocks with the Swedish Ohlins we use on V8Supercars etc. But I have compared Japanese Ohlins car shocks with the Swedish Ohlins and they are totally different. Piston design, casting, valve layout, adjuster methodology, they are all different. Cheers Gary

You're both Johnny come latelies, it was the early '70's. Check out your history, 1971 Bathurst Hardie Ferodo 500 first in Class C Mazda RX2. The revival in the late 80's early 90's was due to turbo chargers and the realisation that at 3.9 litres a 13B made a good turbo engine with it's low compression ratio. Hence overcoming one the rotary engine major drawbacks, the inability to achive high compression ratios. Cheers Gary

That's what I said 20 pages back and you pulled out the insults and said I didn't know what I was talking about. Since you now agree with me on the capacity, let's move on to the 2 stroke/cycle discussion. You are still following the same Mazda lies as on the true capacity, you are looking at only one side of the rotor and saying it's a 4 stroke/cycle engine. That would be like looking at the piston crown in a 2 stroke/cycle piston engine and saying it's a 4 stroke/cycle engine. For the very same reasons it's illogical to only look at only one side of the rotor, when the undeniable fact is another side is inletting while the side you are looking at is combusting. That's a 2 stroke/cycle at work. Now the non thinking rotary supporters point at the fact that a rotor has 3 sides, which of course is true, but it's irrelevant when determining the difference between 2 stroke/cycle and 4 stroke/cycle. The fact remains that a 4 stroke/cycle engine does one of the 4 things at a time and a rotary doesn't, so it can't be a 4 stroke/cycle engine. A rotor does multiple parts of the combustion cycle at the same time, hence it's a 2 stroke/cycle engine. For the others, go back and look at what I have posted and you will find nowhere have I knocked the rotary engine itself. What I have a problem with is Mazdas 40 years of lying on capacity, rpm and 2 stroke/cycle. The engine itself is fine and I would have no objection if the truth of 3.9 litres (using a 13B example), 2 stroke and 3,000 rpm had been revealed from the start. So do rotors suck, no they don't, but Mazda does. Cheers Gary

And yet you won't help me out be answering a very simple question ""2. if you rotate 1 x 13B rotor 360 degrees how much air does it pump?" Why is it that you don't want to answer the question, obviously you know the answer, so that's not why. Could it possibly be that the answer destroys your argument? Surely not. Let me clear one thing, I'm not knocking rotary engines, what I am doing is simply pointing out the facts as I see them and supporting those facts with reasoned arguments. What I don't like is the Mazda lies for 40 years, that started for 100% for marketing reasons and have had repercusions ever since in motorsport. But the rotary engine itself is not the subject of that objection. Cheers Gary

Well I'm confused, what's time got to do with capacity? On that basis a 5,000 rpm 2 litre engine has half the capacity of a 10,000 rpm 2 litre engine, because of the number of firings over time. Then what about a 2 litre 2 stroke engine? They have twice as many firings in the same time frame, does that mean their capacity is 4 litres? Of course, that's because it's a 3.9 litre 2 stroke, arguably equivalent to a 6.8 litre 4 stroke. Just to compound the idiocy of it, CAMS counts them as 1.3 x 1.8 = 2.3 litres. Any wonder they do OK, despite only 3,000 rpm. Cheers Gary

But a rotor has 3 faces, you can't look at one face in isolation. We don't look at one cylinder in a 4 cylinder piston engine in isolation, so why should we ignore the other 2 sides of a rotor? That's cycle position of the eccentric shaft, not the cycle position of the rotor, which is after all the pumping medium. No they're not, you don't doube a 2 stoke engines capacity, or halve a 4 strokes capacity depending on crankhaft degrees of rotation. Their capacity is defined as how much they pump for a complete cycle of their pumping media, ie; their pistons. But when we get to rotaries, Mazda (and it would seem you) expect us to divide the amount they actually pump by 3. I completely fail to see the logic in that. This is the basis of our dissagreement, you want to use eccentric shaft revolutions to influence capacity measurement and I see no logic in that. It flies in direct contravention of every other pumping (capacity) measurement of every other type of engine. That, by the way, isn't the question I asked. I'm guessing that you didn't answer the question because you don't like the answer. In the persuit of truth, let me repeat the question "2. if you rotate 1 x 13B rotor 360 degrees how much air does it pump?" Cheers Gary

Well at least we got back to the facts, please answer 2 questions; 1 why are you using eccentric shaft degrees to measure capacity? 2. if you rotate 1 x 13B rotor 360 degrees how much air does it pump? Cheers Gary BTW, anytime you want to compare CV's, I'm up for it.

So now it's personal insult time, if you can't support your argument with facts then insult the opponent. Not a very good tactic. Cheers Gary

Realy, so how does a 13B go when you put a 1.3 litre sized turbo on it? Prettry terrible actually. But when you put a 3.9 litre sized turbo on it they go OK. Further proof of 3.9 litres, as if we need it. Ah......no...........what I am saying is a rotary tacho is manipulated to show eccentric shaft revolutions of 9,000 rpm when the fact is the rotors are only doing 3,000 rpm. Cheers Gary

Ah, the old changing the subject trick. So that means you give up then and agree that I'm right? Cheers Gary

Clearly someone who understands how a rotary works, but is trapped by the 40 years of Mazda lies. It's not layman's terms, it's Mazda's terms, you are simply regurgitating the Mazda myths. So let's get down to the real facts, why are you using eccentric shaft degrees to determine capacity? No one does it (count crankshaft revolutions) with piston engines, but Mazda does it with rotaries. Try it with a full cycle of rotor motion and you end up and 3.9 litres for a 13B, ie; use the same method as everyone does with a piston engine, a full cycle of piston motion. That's the problem with Mazdas flawed logic, it's a useless attempt at comparing crankshaft revolutions with eccentric shaft revolutions but completely ignoring the facts of engine capacity measurment and then compounding that error by ignoring the simple mathematics. Why? Because it didn't fit with their publicity, it's marketing calculation not an engineering one. The fact is it's completely irrelevant how many revolutions of the eccentric shaft, that's a gear ratio and, as such, has absolutely nothing to do with an engine's capacity, which is how much it pumps. In the case of a 13B that's 3.9 litres for the completed cycles of its 2 rotors. Cheers Gary

Hence why I will respond. What you are describing is gear ratio, diff ratio and tyre diameter effects. If I want to travel 50% less distance, then I simply lower the gearbox/diff ratio. or fit some smaller diameter tyres What has that got to do with engine capacity? Nothing. Nobody halves the true capacity of a piston engine just because it combusts every second revolation of the cranshaft. So why should we allow a rotary engine to devide its true capacity by 3 just because the rotors turn at one third eccentric shaft speed. There is no logic there. Regardless, I'm not falling for the trap of comparison, the fact remains a 13B pumps 3.9 litres for every complete cycle of its rotors. Whether that's the same as a 3.9 litre piston engine is irrelevant. The difficulty the blind rotary supporters have with me is I can point to a number of rotary engined cars and say I built/helped build them. I don't have an anti rotary agenda, my agenda is quite simply to tell the truth, expose the 40 years of Mazda lies and dispell the urban myths surrounding them. The fact remains a 13B is a 3.9 litre 2 cycle rotary engine where the rotors (the all important combustion components of the engine) only rev to 3,000 rpm. Don't confuse that with saying a 13B is the same as a 3.9 litre 2 cycle piston engine where the pistons (the all important combustion components of the engine) only rev to 3,000 rpm. That's not my argument, because that would be attempting the impossible, equivalency is a fallacy. Cheers Gary

No problem, I'm impervious to personal attacks anyway, it just detracts from good quality discussion. OK, you're entitled to your opinion, but let me mount a counter argument. Using your definition of a 2 stroke/cycle engine, it's blatantly obvious that a rotary engine most definitely shares cycles. Whilst one side of the rotor is inletting another side is exhausting, hence its a 2 cycle/stroke engine. Obviously there is a 3rd side of the rotor that is combusting, but in your definition that's irrelevant I think the problem here is you are still trying to equate a rotary engine with a piston engine and we quite simply can't do that. What you are doing is looking at one chamber at a time, like it was a piston. The problem is in a 2 stroke piston engine there are 2 sides to the piston, the crown that combusts and exhaust and the underside that inlets. In a rotary engine there are 3 sides and we can't look at one side only when determining if it's a 2 cycle engine or not. Again, we can't relate a piston engine to a rotary engine, even when it comes to somthing as apparently simple as 2 stroke/cycle versus 4 stoke/cycle. The fact is a 13B (for example) is a 2 cycle/stroke rotary engine. That's not the same as saying a 13B (for example) is the same as a 2 cycle/stroke piston engine. The same problem again, you are attempting to convert elipical motion to up and down motion and that's fraught with danger. If you stop thinking of strokes as up and down motion, perhaps just use the alternative meaning of cycles. You then come to a completely different view of what constitutes a 2 cycle engine, and that a rotary is most defintiely that. The "powers to be" were Mazda and they had an agenda and a major part of that agenda was to avoid at all costs the linking of rotaries with 2 stroke/cycle lawn mowers. That would have been disasterous when they were launching a new technology engine 40 years ago. It's exactly the same reason for the 1.3 litre lie, they didn't want expectations of 3.9 litre power. But is it not a 2 cycle engine? Cheers Gary

I'm not comparing rotary capacity with anything else. The facts are quite simple, a 13B pumps 3.9 litres in one complete cycle of its 2 rotors, that's it. Whether or not that's the same as a 3.9 litre piston engine is irrelevant. No need to count eccenteric shaft revolutions, it doesn't matter how many sides it has, the fact is a 13B is a 3.9 litre rotary engine. Supporters of Mazda lies about 1.3 litres try to muddy up the water with meaningless comparisons to piston engines which is exactly what they are, meaningless. It the same as the 2 cycle truth, the rotoary combusts every cycle, not eveery second cycle which is what defines a 4 cycle engine. There is no argument, a rotary engine is a 2 cycle engine, end of story. Cheers Gary

OK so you agree with me that the rotors only do 3,000 cpm. Let's leave it at that and carry on. So you agree that a 13B pumps 3.9 litres in one complete cycle of it's rotors. Now would you like to go back and check the 2 litre 4 cylinder 4 stroke engine pumping 2 litres for every rotation of its crankshaft? It actually pumps 1 litre, it takes 2 revolutions of the crank to pump 2 litres. So using your logic of eccentric shaft revolutions somehow making a difference to an engine's capacity, then a 2 litre piston engine should really be rated as 1 litre. Now I don't know about you, but I don't do that for a piston engine so why should you expect anyone to do it for a rotary engine. The lies started when Mazda convinced the Japanese registration authorities to only measure one side of the rotor. This resulted in two things, firstly cheaper registration because rego in Japan was based on engine capacity. Secondly it was marketing trick, small engine lots of power. Once the lies started they couldn't stop and so they spread to motorsport, which is where I have the most problem. You believed the lies, that's OK you were only 8. Back to your point, it's only unfair when a supposed 1.3 litre rotary engine is compared to 1.3 litre piston engine. That's where Mazdas marketing was aimed at, that's where their motorsport homologation was targeted. And it's all based on untruth, even using Mazdas "formula" it should be 2.6 litres. Using any logic of an air pump, which after all is what an engine is, it's a 3.9 litre. You are confusing the meaning of "stroke" (up and down) in relation to an engines "cycle", it is quite common to replace the term "2 stroke engine" with "2 cycle engine". You are doing exactly what you accuse me of, trying to compare a piston engine with a rotary. Don't do it, think of it as a rotary engine, forget pistons and up and down. Now if you still have a problem with the term "stroke" being applied to a rotary then substitute it with "cycle". So back to the question, is a rotary a 2 cycle engine? The answer is yes it is, absolutely. I'm sorry I don't understand, piston engines have crankshafts, rotaries have eccentric shafts so there is nothing common there. Why are you trying to make something that is inherently different somehow the same when the fact is they aren't. Cheers Gary

I'm not sure what is meant by "off the shelf" when it comes to MCA's. I tell Murray what car it’s for, what range of spring rates I intend using, what anti roll rates, what tyres, if it’s a new car to us I also tell him the movement and leverage ratios. I also talk about the tracks we are running on. I have never just picked up the phone and said “send me a set of shocks for a Skyline” and then hung up expecting to get exactly what I need via courier the next day. That’s just not how we work. Plus Murray mostly uses Kings and we only use Eibachs, so we tend to get shocks only from Murray. Murray also sends the shock dyno files so we can compare them with our own shock dyno outputs. That tells us when the shocks need servicing or if we have a problem at a track. Using that method I have only ever sent one pair back for mods and that was due to bad info on a car I personally hadn’t seen, weighed or measured. It was a prime example of garbage in = garbage out, hardly Murray’s fault. Even then they weren’t that far out, we just wanted the adjusters closer to the middle of their range. Tuning wise we have a standard new car program we follow for Production Cars, which I have used for 15 years or so now. It’s very similar to the V8SuperCar and F3 new car / new driver development procedure that we follow, just simpler mostly due to no aero to confuse the issue. As usual with motorsport it’s all about having the resources and how you use them. Cheers Gary

OK, let's break this down into 3 simple questions and answers; Firstly RPM, I have stated that the rotors only do 3,000 rpm, are you denying that is correct? Next capacity, a simple question really, how much does a rotary engine (say a 13B) pump in a complete cycle of it's 2 rotors? The answer is 3.9 litres, surely undeniable isn't it? Lastly rotary = 2 stroke, again a very simple question. A rotary inlets, compresses, combusts and exhaust in one revolution of the rotor. If that is true, and it is, then they are a 2 stroke, agree? These are my 3 statements, simple and concise, no muddy water. You either agree or dissagree, if you dissagree then please tell me why. Now which 50% of your arguments am I ignoring? Cheers Gary

Ah excellent, since you have decideed to attack the man not the argument I assume that means you have lost and give in. Understandable, since I'm right and eventualy that reality dawned on you. Cheers Gary

Not that it has anything to do with this thread by my versions of the baron's post. I always knew an RX7 was a 3.9 litre elliptical engine that produced 230rwkw at 3,000rpm. first turbo kicking in at 800rpm and second one at 1800rpm holding strong to the 3,000 range. It's blatantly obvious. I like engines,. I like the RX7s 13BBP, I like the RB31DET in my Skyline and I love the 3 Litre straight 6 in my M3. Hey the RB25DET in my Stagea is pretty kick ass too. Working on an Evo X 4G63 on and off, plus getting an Evo 7/8/9 soon and I love the 2 litre 4 pot in the Integra TR's. I guess I just like engines. they all have their strong and weak points. the 13BBP's break if I look at them the wrong way. the RB31DET don't like too much revs and may decide to break an oil pump just to piss me off. the 13BBP's and the RB31 drink fuel like it's me on a Jack Daniels the NA K20A motor lacks that fat midrange, but its getting a 2.4 litre crank to fix that. the M3 is just too good at what it does and it's never depressing, I love the song of a BMW I6. I quite like the Cummins 12 litre VGT (variable geometry turbocharger) that is in the race team transporter. It has 1600 ftlbs of torque and 425 bhp and for it's purpose it's perfect. It has a redline of about 2,500 too, so I think it works the same as a 3.9l 3,000rpm rotor, except it's not a 2 stroke. Cheers Gary

But there's a gearbox in between the engine and the driveshaft. So how we measure the engine rpm depends on what gear the box is in? Surely not!. That's the problem, the gear ratio between the rotor and the eccentric shaft is exactly that, a gear ratio. It's purpose is exactly the same as a gear ratio in a gearbox or a diff ratio. That is quite simply to change the ratio between the number of revolutions (cycles if you prefer) of the rotors and the number of revolutions of the tyres. Whether that gear ratio is inside the engine, inside the gearbox or inside the diff doesn't matter, it's still just a gear ratio, nothing more. The fact remains, the rotors are doing 3,000 rpm, an indesputable, irrefutable fact. No it's not, go and read the original books on rotaries. What Mazda did was take the capacity of one chamber, like it was a cylinder in a piston engine. The rotor is then a piston in that cylinder. Hence a 2 rotor engine's capacity is simply the capacity of one cylinder multiplied by 2. They conveniently ignored the fact that each rotor has 3 combustion "sides", unlike a piston that has one. For those of you complaining about comparisons to piston engines, well Mazda started it with how they measured the capacity. How does the number of piston/cylinders change the rpm? I'm confused. And therein lies (sorry) the problem. A 3.9 lite engine has been competing illegally as a 1.3 litre engine for far too long. Cheers Gary

I like that word, "enginist", thanks, I might continue to use it. Not true, I just object to Mazdas 40 years of lying. Again not true, what I object to is Mazdas 40 years of lying. As a result rotaries have been able to compete unfairly in all forms of motorsport. It's cheating, gross cheating and that's what I don't like. You really don't know me very well at all, right at the moment I am working on a rotary engined car with another rotary on a engine stand next to me. I haven't compared the method of measuring the capacity of a rotary with the method of measuring the capacity of a piston engine. All I have done is measure the proper capacity of a rotary engine. The fact is a 13B pumps 3.9 litres of air in one revoltion of the rotors, that's an irrefutable fact. Hence it's a 3.9 litre rotary engine, indesputable mathematics. There is no argument. There is also no argument that the rotors rev at 3,000 cpm, another irrefutable fact. Yes, I used cycles per minute as someone objected to the term revolutions being applied to a rotary, not that it matters in this context. I agree that comparing a rotary engine with a piston engine is fraught with difficulties. But that's irrelevant to the fact that a 13B is a 3.9 litre engine that revs at 3,000 cpm. If you want to debate those facts then let's do it, don't try muddying the water with irrelevancies. That's me. Surely that isn't a positive, because rotary's general public perceived value would be zero. Unreliable, expensive to maintain, lousy fuel ecomomy and a big polluter would be the most common terms applied. For 40 years Cheers Gary

I can’t give a good Skyline example as the cars have progressed over a number of years, through many iterations. I can however give an rock solid Integra example. As you know we have had a DC5 racing in Production Car trim for 3 years running Tein N1’s (~$6K). Which, over that time, I had sent back to Fulcrum 3 times for revalving and twice for servicing to fix oil and gas leaks. Plus completely changed the spring rates as they were ridiculous out of the box. After that amount of time and effort I figured we had optimised them as best we could, the car was fast enough for the class pole position and race lap record at the Bathurst 12 Hour. When the chance came along late last year to run a second DC5 we went for MCA’s double adjustables. I had a pretty good handle on the spring rates and Murray chose the valving based on the spring rates, the corner weights and movement plus leverage ratios I told him over the phone. Out of the box the #2 car, according to the drivers, was faster and easier to drive. With very little tuning of bump settings and no change to rebound, at Bathurst it was ~2 seconds a lap faster than the #1 car with the Teins and set a new class qualifying and race record in the 12 Hour itself. We just literally ran the opposition into the ground, they either crashed or broke their cars trying to keep up. Actually I can give a simple Skyline example, an R33GTR. It had Yamahas (Japanese Ohlins) in it originally and they started to leak, gas and oil. I couldn’t get them serviced anywhere locally, so I dropped in a loan set of MCA (Proflex as it was back then). Straight out of the box the car was way easier to drive, it did the same lap times without stress, on the driver or the tyres. I spent one day tuning the damping, both bump and rebound, and it was 1.5 seconds a lap faster at Eastern Creek and the tyres lasted a whole weekend. Previously it would chew through a set of fronts in 2 sessions. Those MCA’s are now in my R32GTST, suitably modified of course. My summation, Murray knows his shit. Cheers Gary

Owned by Klaus Wohlfarth, a mechanical engineer, that's where the "KW" comes from, started in the early '90's. Shocks are made in Germany in KW's own factory, coils though are wound by Tevemen from memory. East Coast Suspension are the Australian agents. They have multiple levels of kits, V1, V2, V3 Clubsport and Competition 2 way adjustable and Competition 3 way adjustable. I've only seen the Competition 2 way with attached cannister and that was on an S2000, the kit cost around $6-7K from memory. I liked the sensible spring rates and the progression in the damper adjustment. They were made of stainless steel and consequently a little heavy. I have seen pictures of the Z33/V35 Competition kit and they have a neat rear height adjuster system. My opinion, albeit from one set only, was they were good quality, European engineered, so OK for our our condtions. Maybe a tiny bit expensive, but well worth considering. I also saw, at SEMA I think it was, a KW hydraulic donut kit that fits around the shocks between the spring and the spring seat. There are 4 donuts, hydraulic lines, a hydraulic pump and a remote control so you can raise or lower the car on the move, about 30 mm was the limit. Very cool, but expensive at around $4K. Cheers Gary

Actually it was a conspiracy, the Large one wanted Moffat in the Australian Touring Car Championship and the only way was to let RX7's, an FIA Homologated Sports Car, race in a Touring Car category. IP Racing still suffers as a result of that breaking of the rules of homologation, the undeniable fact is RX7's are Sports Cars and they shouldn't be allowed to run in a Touring Car category. Meaningless diversion anyway, that's a car and we are talking engines here, rotary ones in fact, so let's get on with it Cheers Garty