Should be fun for as long as it holds together.
Should be fun for as long as it holds together.
Keith Tanner said:
Yes, that's a turbocharger force feeding a supercharger. The packaging simply demanded it.
That packaging is just berkeleying beautiful!!!
I've long wanted to supercharge my Alfa but the only "kit" available to us looks like something that was made in my back yard on a challenge budget...
after we spent most of it on beer...
Toyman01 said:Could you stage them so the supercharger took care of the boost until the turbo took over? Zero lag at a reasonable and survivable amount of boost.
They need bypass valves. Here's a video I love of a bypass valve in action on a twin charged audi
Lancia did this on their Group B rally car - don't know if they had such a system on any road-going cars.
Very interested to see where this goes..... 
How beefy are the 2.0L SkyActiv internals? I know that there are turbo 1.6L Miatas making 300hp to the tires on stock internals (one has been together and street-drive and raced for over 2 years) and I know that the 1.8L pistons and rods are good to ~300ish as long as you keep the rpm reasonable and the cranks and blocks will hold 700+hp.
Those numbers are a little more optimistic than I’d claim 
Who the heck is making 700 hp on a stock crank?
i don’t think we’ve found the limit of the Skyactiv stuff yet. It’s been limited by other things.
Keith Tanner said:Those numbers are a little more optimistic than I’d claim
i don’t think we’ve found the limit of the Skyactiv stuff yet. It’s been limited by other things.
BP Performance Specialties has a 700+hp turbo BP-4W in a Festiva with the stock crankshaft and block.
Rodan said:Very interested to see where this goes.....
As am I. Just how mad scientist are those boys in Colorado going to get?
It needs double the forced induction because they live in the mountains. What other choice did they have?
Im curious why the owner wanted to switch to the supercharger.
Reading your posts regarding the bbr vs edelbrock kits on the nd, ive got the feeling they make similar peak power, limited by injector, but the bbr makes more mid range and is more consistent with elevation.
Im test driving nds tomorrow, this is very relevant to my interest
A roots blower should make it just feel like a bigger NA engine for the most part, so I can see the appeal.
Opti said:Im curious why the owner wanted to switch to the supercharger.
Reading your posts regarding the bbr vs edelbrock kits on the nd, ive got the feeling they make similar peak power, limited by injector, but the bbr makes more mid range and is more consistent with elevation.
Im test driving nds tomorrow, this is very relevant to my interest
The owner is Flyin’ Miata. We already have a turbo R&D. Our 2017 RF was turbocharged for the CARB testing as well as a round of magazine tests. But now that those tasks are complete, we need an R&D supercharged car because we sell them and customers often ask us for comparison drives. If we had an unlimited number of NDs, we’d probably keep it turbocharged. Heck, we would have left it with the hot naturally aspirated motor and turbocharged something else, then supercharged something else again. But such is life as an FM car.
Come on Keith, We all know FM cars never change from their first build and you have a test fleet the size of a large miata club.
Could you stage them so the supercharger took care of the boost until the turbo took over? Zero lag at a reasonable and survivable amount of boost.
Without a lot of additional trickery, the SC would always be pumping air and all the air will always be going through the SC. However, you do get around some of the downsides of the blower (inferior adiabatic efficiency to a turbo's compressor, generally) by using it to achieve only some of your 'compression'. For example, if you use an SC to get 20psi of boost you'd generally have a pretty terrible charge temp. If on the other hand you use a turbo to get 7 psi and then feed it through a supercharger and end up with a total of 20psi, you'll have it at a lower charge temp.
That's not enough of an advantage to 'justify' this type of compound setup, though. Compound setups on gas engines usually aren't about peak power but power under the curve. Even then, you don't really see huge advantages vs just a supercharger unless you're going for a power level that would require a ridiculously large supercharger for your base displacement, which has a lot of downsides. So, if you are going for a power level that would be difficult to do with supercharger alone, and also want a ton of power under the curve, then sure!
For that to be true, the turbo itself has to be able to flow the amount of air your peak power requires, so 'big' turbo (for a 2.0). On a compound turbo+super setup you'd want to use a turbine that's very large for your engine displacement. If you are running a 2.0L with the supercharger running at a 2:1 PR (~15psi boost), you'd be running a turbine sized for a ~4.0L engine because that's how much exhaust flow you're generating. You want to run the biggest turbine section that will give acceptable response because bigger turbines create less backpressure which means less power eaten by the exhaust strokes of the engine. When you're talking about a roots/screw blown engine, 'acceptable' response becomes pretty forgiving because you're going to have your 'low boost' setting instantly anyway. Miatas run 14s stock. Add any amount of boost at low rpm and all of a sudden you'll be perfectly ok with your turbo not spooling til 4500-5k rpm so you would probably end up with a turbo that's BIGGER than what you would choose for a turbo-only 4.0L street car.
Trans_Maro said:Should be fun for as long as it holds together.
So everything I read tells me that boosting a Miata will result in heat management challenges in a road-course situation.
I can't help but wonder if this is going to make for more trouble?
On a bonkers scale, its is at the top of the class and I am glad that FM is doing it!
Pete
NOHOME said:So everything I read tells me that boosting a Miata will result in heat management challenges in a road-course situation.
Not everything you read. It's about proper prep.
http://www.roadandtrack.com/car-culture/a14500141/flyin-miata-turbo-nd-torture-test/
Will this be worse? I guess we'll find out. We're certainly not helping airflow across the rad with heat exchangers for each booster (that is my new term for a single Forced Induction Unit). We've theorized a lot of what will happen here, but we're not 100% sure. The turbo is not going to be a limitation, it's already big enough to support 350-ish hp. The super will be acting as a multiplier, so it'll be able to handler higher power levels than it would be if it were breathing unpressurized air. But really, the rest of the platform isn't ready for that sort of behavior yet, and this is a ridiculously expensive way to solve problems that don't exist - the turbo doesn't suffer from a weak bottom end and the super doesn't fall off at the top. So really we're putting this together because we can, because we're curious and because we think it's awesome. We'll learn something and of course it underlines the fact that we happen to sell both turbos and superchargers, which is good justification from the marketing department to help out the guys who budget R&D time
Hungary Bill said:Keith Tanner said:
Yes, that's a turbocharger force feeding a supercharger. The packaging simply demanded it.
That packaging is just berkeleying beautiful!!!
I've long wanted to supercharge my Alfa but the only "kit" available to us looks like something that was made in my back yard on a challenge budget...
after we spent most of it on beer...
I so wish my thrown-together-for-the-berkley-of-it projects could look like that! My stuff usually functions as desired, but always looks like complete poo.
Oh and Kieth, we're going want a proper video of the dyno tuning session. If that thing grenades the video would be epic
If it does run too hot, put a few of those drip system sprayers on it to wet down the heat exchangers a bit and cool them off
Did something like that back in 2003 for the Open Track Challenge, actually...
Appleseed said:Rick Dobbertin says, "Needs moar staged nitrous.
I came looking for a Rick Dobbertin J2000 reference, was not disappointed.
Is this an engineer's way of saying, "Here, hold my beer?"
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