Supercharged QV (take 3)-or is it a turbo?

Well, it's been 2 years, so it's time for another couple hundred hp

I bought the first part for the new system today on ebay, so I guess it's an offical plan now so I'll share. The first part is a honda avt CVT transmisions, which might make you ask, "what on earth does he need with an atv trans in a ferrari"?

Well, I'm thinking what I'm going to do is put a turbocharger on the car because they are more efficient....but I have turbos. So, I got it in my head what I need to do is add an ECU controled mechanical drive to the turbo to keep it spooled to eliminate lage and and provide the power to generate boost at low rpm...so now the CVT trans makes sense (at least in my little world).

The other part of the plan is that, at least in theory, I can get rid of the wastegate and use the CVT to control boost and dump the excess turbine power back to the crankshaft.

This is going to be cool, so stay tuned!

Oh, and port the heads and design a new intake of course

 

That is why god gave us gears

I'm going to use a pretty fricken big single turbo to help addres the rpm issue as well as move the air I want. The plan is for about 25 psi in the 60k to possibly 100k rpm range.

It would be a very "80s" lagy system without the mechanical assist, but with the assist it will on par with any other supercharger system for responce and power output at or above a standard turbo since there will be no energy wasting wastegate - any power above what is required to drive the compressor will to delivered to the crankshaft, basically allowing the turbocharger to become a gas-turbine engine coupled though the variable drive to the piston engine.

 

I thought it was a great new idea until I found dozens of patents on nearly every conceivable way to do it over the years including...I don't get out enough.

 

It will be going on the (ebay) block at some point soon. I want to get flow numbers on the intake first though to help with the new intake design.

 

I've never driven a turbo street car that I personally found acceptable....so this will be a supercharged car with a turbine assist. If I can't get the turbine part to work properly, it will go in the trash... but the supercharger part that I know how to do well will stay.

 

sure,
I'll sketch something and post it later today

I after spending a couple nights searching patent databases, I discovered that most everything I'm thinking of has been claimed at one time or another, just not all together or exactly the way I'm thinking...but the moral is I could probably get a new patent, but it wouldn't be worth the paper it's printed on - so there's no harm in sharing and feedback is always a good thing, that's why I started the thread.

Mercedes came very close in patent 5729978, but without the (I think) required CVT, click on images if the link works.
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1=5729978.WKU.&OS=PN/5729978&RS=PN/5729978

 

Yes, if it's a blow though type set-up, but then there is still the hugh step in the torque curve when the turbo spools, so nothing is really solved. A parallel set up can make unifor boost across the rpm range, but it's pretty tricky to clutch the blower in and out smoothly.

i may not be able to get it to do what I think I can get it to do...but by then 2 years will have gone by and it will be time for a new system again anyway

 

That's still on the list. I honestly don't think the market is large enough to actually make money though and I like to spend my free time doing stupid things to my car.

I'm suppose to be doing something with/for another f-chatter soon that would be about the design for a system I think would be right for the kit market. When I do, I'll post something and maybe do a group buy or something so I can run a few all at once.

 

What I'm really worried about the most is the surge limit on the compressor maps I'm looking at....I'm not sure I can find a single compressor that will flow the pressure I'd like right from idle without ending up in the surge region, which is a bad thing. I can make 5 psi at idle easily, but I'm not so sure about 25. If I can't find a suitable compressor for the turbocharger, I'm going to need to do some re-thinking....like a screw type compressor and put the CVT between the compressor and the turbine.

 

After a more consideration there is a reason nobody adds a motor to a turbo...and surge is it's name. If I drive a centrifigal compressor to make boost at low flow rates the compressor will surge and destroy itself. So I'd have to run the compressor above the surge line and bleed off the excess flow....and that would be both very wasteful and the condition that exists more of the time on the street. This was a terrible idea.

The new plan is a dual system as several have already suggested to me...ok, so I'm a little slow.

I need to get some professional help specing the turbo, but what I found so far makes me thing a garrett GT42 might be the right choice. for 25-30 psi boost, I think I need about 70 lb/min air flow. The compressor map says the compressor will surge at that pressure below 35 lb/min, so the turbine can't drive the compressor to full boost before about 4000 rpm....driving around on the street I generally shift at 3500 or so. This is why I hat turbos.

So, it needs a supercharger that can get me to 30 psi up to 4000 rpm and I think I have 2 choices on how to go. I can put on a blower the is about 1600cc , start opening the bypass to feed in the turbo about 4000 rpm aand clutch out the blower by 4500...where it will be redlining to make the boost

Or I can use the fancy CVT I bought with a 1200cc blower, and let the turbo start making what boost when it will when it will and use the cvt to fade out the blower by 4500.

I need to do some more thinking.

Then I have a cou

 

I'm thinking a flatter torque curve with more overall power. Maybe limit the boost in the lower gears to help traction.

 

I guess a T66 would do, the T60 doesn't seem to even be mapped to 30 psi (pressure ratio 3.0), so I don't see that working.

They haven't gone to the GT42 which appears to flow more than the t66, but has a lower surge line? It looks a touch bigger than I need - I've got maps for 102mm and 94mm, and even the 94mm flows a little over 80 lb/min, I think I only need 70, and surges at about 35. I'd like to find something shifts the whole map lower a bit and get 20-70 or 25-75.

I guess since I'm off the hydraulic drive and on to twin-charging now there is no reason I couldn't TT it....but that seems like a lot of part, especaill if I go with the CVT on the supercharger.

Here's what I'm thinking for the system:
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