Number of cars running MazdaManiac's system for 3+ years = 1
Number of cars running Hymee's S/C for any appreciable length of time = 0
Number of engine blown because of boost between the two = 0
Number of development days for MazdaManiac's system = ~60
Number of development days for Hymee's S/C = ~1440 and counting

I could keep going, but the pwnage is burning my eyes...
Its 2 motors, BTW. I plan on blowing the current motor at some point as well. That is part of the learning curve. What have you done to contribute?

 

haha oh man =X

 

You make the interesting assumption that MM blew up engines because either his kit sucked or because of bad tuning. Neither has been the case and you'd know that if you'd go read some older posts. The last one was purely user abuse and he'll admit that.

I rode in his car this weekend. It feels very nice. I also discussed his timing methods and again they seem quite nice. There wasn't anything that I disagreed with. He's a pretty straight shooter. He learns and shares his results along the way whether it's a good outcome or not. There aren't many places that discuss their failures during development. Keep in mind I'm not talking about Hymee anywhere in here. The point of this is that unless you prove otherwise, you've got no room to insult MM for ANYTHING!

Hymee's kit is a work of art. Absolutely beautiful. Very well engineered and well thought out. It's also been an evolution fixing issues along the way. Comparing these two to each other is a waste of time. They both know each other and both can understand that there is a place for everything.

 

RG .........it was never my intent to insult MM , as a matter of fact i enjoy reading his post /avatars as well as yours both for your individual knowlegde of the rotary and the sharing of info and help you guys give the rotary community .

I was only pointing out to MM the self appointed advocate of F I Systems that others also have equal status in the forum and Hymees efforts are also respected equally to his .

Cheers
Michael

 

Wow. Nice back-pedal.
Well, not really. Pretty sloppy, actually.

Didn't you say:

What does any of that have to do with "respect", "status", "self-appointment" or "advocacy"?

 

Doh...
This is beginning to get real old, using the blown engines as an excuse. WTF?
Dude, if you would have met MM in person, looked at his work, talked to him, you'd keep you mouth shut about such nonsense for the rest of your days.
When I was pushing 14-15 PSI on my car recently, and if (thank god it didn't, but if) my engine would have blown would that mean I don't know the method too? I sure did know the risks of running over 12AF @ that boost pressure, but regardless I bet half the forum would start bitching how rotorocks' system is crap because he's blown a motor. On the other hand I haven't blown any motors, and I still listen to what Jeff has to say with booth ears, and my mouth open. Why do you think that is?

There are people who blow engines because they are plain stupid, and there are people who do it because they want to find out. And as such they willing to take a risk. There are also people ho don't want to take the risk, but just want to operate within the "reasonable" limits.
Are you willing to risk something like that and post your findings?
Somehow I didn't think so.

 

Sorry, Hymee. I guess I pooped in another one of your threads!

 

Don't even give him the time of day, Jeff, it will go right over his head........

 

Yikes!

Again!

 

What are the advantages of Hymees new Electronic Throtle Body as opposed to the stock one ?



Cheers
Michael

 

Nothing on a naturally aspirated car. On a supercharged car that pulls air through the tb, it's all about flow. His is larger. If we compress air before going through it as in a turbo, it isn't necessary.

 

I was actually noodling that notion in my head right as Hymee started talking about it during his presentation.
Isn't a flow restriction a flow restriction?
I realize that flow cross section relates to velocity at an equivalent mass, but is the drop in pressure across the TB just as relevant post-compressor as it would be pre-compressor?
I would guess not since, with a turbo, you could just add pressure to compensate for the target and as long as you are not going off peak efficiency you would net zero loss.
But then, wouldn't it be the same thing at the other end with the SC? Is compressing a slightly lower air mass slightly more not the same thing?

Turbos have a drop across the inlet that is a loss - typically about -3kPa. On an SC moving 35 - 40 lbs of air (just like the turbo), wouldn't the loss be the same?
The inlet of a typical street turbo is smaller than the TB.

 

RG / MM thanks for your replies i will try and get my head around it



Cheers
Michael

 

Enough banter between the MM and ME please!

As for TB's go... A TB will become a restriction on a turbo / "push through" at some point. It is just that in a "draw through" - where the TB is before the compressor as in a normal PD S/C setup, the size of the TB needs to be larger. In fact, if you check out the Autorotor documentation, the RX-8's TB is too small for this size blower.

Testing on the engine dyno and on the road will help sort out what size is required.

Yep - and Ajax gets the points for the scoop. Electronic Drive By Wire Large Bore Throttle Body. Fully compatible with the wiring loom / computer. Plug and Play.

Cheers,
Hymee.

 

Yes, but why?
The change in orifice is a change in velocity if mass stays the same.
I get the whole "sucking through a straw" thing, but 40 lbs of air is 40 lbs of air.
Increasing the nozzle size 1/2" is an infinitesimally small change in efficiency and an almost equally small change in velocity - not even 10%

I just want to see the math.

 

True that a certain amount of air is a certain amount of air in total mass but that doesn't mean it is of the same density or takes up the same amount of space. If you compress the air, it's the same amount in a smaller area. This means that it flows more easily through an orifice of the same size. The amount of work necessary to force the extra air through the orifice of that size is done by the turbo/supercharger during compression. It gets compressed before it gets there and not in there. The inlet of a turbocharger is always larger than the outlet for this very reason. The air takes up less physical space after the compressor.

Going from a 75mm throttlebody (2.96") to an 85mm throttlebody (3.36") is a pretty good area increase. That's going from 6.88 sq. inches to 8.86 sq. inches. That's an increase in area of over 29%. While flow doesn't follow that exactly in terms of percent increase, it stays pretty close. A 100mm tb would be twice the area of a 75mm unit.

 

The sucking through the straw thing is it. I'm sure you have heard of intake restrictors? I know you have. Forget the whole size of the engine and the functionality of the blower. The whole system can only make as much power as what the intake restrictor lets it draw in.

Here is a little bit of math, with made up, but close numbers, to demonstrate some of the principles.

70mm TB = 3848 mm2
80mm TB = 5027 mm2

5027 is a 31% improvement over 3848. (And 31% is 310% more than 10% )

The real number is more like 39.4%

I hope that helps a little. Like I said in my presentation - I need to run a number.

And a little correction in the time in development. Yep, it has been 3 years, give or take, in elapsed time. The real amount of effort was about one or two full time man weeks for prototype 1. Two or three full time man weeks for prototype 2, including that mint 3" exhaust system. A week or so man weeks for engine dyno work, including prepping (lots of logistics) and time spent on the dyno, both aspirated and blown. A few hundred hours of CAD drawings and design time for what I took to SSX and about 50 hours for the CNC machining. That all took place over about a 6 or eight week period leading up to SSX - roughly since I began this thread I think. All figures of the top of my head, but I have a pretty good recolection of events.

As for blown engines... C'mon guys. It isn't a big deal either way. I'm pretty sure I mentioned in the first thread of my main "... Superchared Part 2" thread, that it was planned to take the first engine to destruction on the dyno. That never happened yet. Firstly because I have a very good tuner (Thanks Grandad!). Secondly cause we never went far enough I guess. Thirdly - a little luck. And finally - we didn't really want put a few thousand dollars worth of parts (smoked engine) in the bin.

All I can say is Wildcards car essentially hopped off the dyno sessions in 2005where I showed those 13-14 PSI tests, then drove 1200 km (or whatever it is) to the nationals, then drove it straight out onto the track.

Everything I/we have learnt along the way has gone into the continous improvement cycle to help get to where we are now. I'm sure keen on running a number.

Cheers,
Hymee

 

Snap!

 

PS - As soon as I post a number, I'm sure I will see the arguments and all the BS start again... Why why why do I do this to myself!

Cheers,
Hymee.

 

way to go Hymee
Nice write up.

So where the hell have you been for the past 3 years again?

he he,
Just kidding.

 

Interesting about the throttle body, as Re-Amemiya in Japan was looking into that. I was always curious about what a different throttle body would do even for NA RX-8s

 

For n/a RX-8's you won't see any gain. If you can see where Hymee's power starts leveling off due to tb flow amount, it is a MUCH higher power level than an n/a RX-8 can make.

 

Yeah, what he said. I've seen the dyno sheets as well. If there's any bottleneck in an NA Renesis, it's on the way out.