It certainly wouldn't be compliant with emissions and noise laws putting out that kind of power but otherwise it is possible...It would be very costly though.

 

I wonder if we could get a cowl hood made to accomodate a 3.0L whipple-charger?

Then the question is.. does the L15 even have the power to turn the blower?

Some of those bigger blowers can take 400HP to spin!

 

That would be taken care of by a traction drive CVT..... People are going over 40 MPH on bicycles with traction drive CVT rear hubs and 36cc motors..

 

so could it be possible that this SC be $2000 give or take a few bucks?

 

I thought it was going to be $3k or so.

F-ing A! If its at $2k, I might freaking do it. Of course, I'd be broke after that. @.@"

Edit: oh crap did I just say that?!? Maybe I won't do it, cause I just remembered it involves more than swapping the top of the engine. If I'm not mistaken, might need new exhaust to accommodate the extra air.

What the heck am I going to do with an S/C anyway?

 

you can't run a SC with a stock exhaust?

 

Mark of sprintex did mention that their sc were installed on a number of unmodified fits in china and australia

 

I drove with 5 PSI boost and stock exhaust with no problems... You need better flow to make more power but too much without larger injectors and tuning can cause big problems.

 

well, i plan on getting an exhaust eventually. exhaust isn't really at the top of my list..... and, when i get this SC, i plan on getting a shop, that has tuning capabilities right there. i'm not looking for massive amounts of power. i know nothing actually about superchargers, and well, anyone know any good sites that have some good reading? or some vids that may help me out?

also, total noob question...and i can't get an answer anywhere......can you put a BOV on a supercharger, and why would you want to, or not want to?

i feel dumb. lol

 

The exhaust basically lets you evacuate the cylinders more effectively. Under boost you want as little back pressure as possible. So a turbo Fit would need the biggest exhaust you can fit back there to run efficiently and spool fast.

Whether or not you need more pipe diameter is going to be determined by your goals and what type of device you will be using to create boost.

And the Sprintex actually has a compressor bypass valve (the recirculated version of a BOV) built in, you can see the actuator/diaphragm is facing the transmission side of the engine in those pictures a couple pages back.

On a Rotrex you can use a BOV, and I would argue you should have one. The Sprintex comes with it's own by-pass valve.

 

Oh.. say you might be on to something there. Using the famed Rotrex drive completely slipped my mind. I wonder if it could be scaled up to deal with the power it would have to transmit?

Hmm now you've done it.. I am gonna have to try something like this when time allows.

You could get away with a larger header (~60mm), have it feed into a bigger B-pipe (also at least ~60mm) and then keep the axle-back stock with a cut-out immediately before it.

A hobbs-type pressure switch would allow it to open and close the cut out when you enter boost or let off the gas.

So when cruising around in vacuum you would have a nice stock sound (minus the supercharger whine ) and then a nice roar when you open the floodgates.

 

This is that CPV/BOV I was talking about:




BOV is just a CPV evacuating to atmosphere.

Here the CPV is re-circulating the charge to control boost on this style S/C because the pulley is overdriven to create more flow/boost then you need so you can have full boost all the time.

The Rotrex only has full boost at redline, and half max boost at ~3500rpm.

 

I need to install a boost gauge and see if you are right about the characteristics of the Rotrex... That just doesn't sound right to me... The CVT works opposite of what a normal CVT does by shifting gradually down as revs climb and up as they drop.

 

The boost gain is not exactly linear, but you really should only see full boost as you approach 6k based on what I am reading. I would be curious to see if you are making more than 10psi too!

 

I was thinking of red line as being when the rev limiter kicks in which is at 7200 by my tach but according to KWSC 7100... Somewhere on the thread about the high boost kit JDMchris mentioned his was 11 or 12 lbs but that was before installing the I/C... I have been pretty stove up because a prescription had expired that need to be refilled and they finally came in so I should be able to get some stuff done now and let you know what I come up with.... What are you reading with the info? Full boost coming on approaching 6K sounds about right... I have noticed that there may be a slight drop in power at 40 MPH in 2nd gear because that is when the tires quit spinning and hook up.... It cant be much of a drop or maybe it doesn't last for a blink of the eye because when it hooks up it sling shots forward.. Would that work with what you are looking at? 7200RPM in 2nd is at 62 MPH...

 

I am still looking through my "vaults" of data, here is the best representation I could find:


The boost curve line should be curvi-linear or linear. This is because as you double the impeller speed, you square the massflow on a centrifugal compressor wheel.



And on a decent intercooler you should see less than 2psi pressure loss, on a nice new garrett core you should see <1psi.

It sounds like you need some sticky tires! I'm sure you probably know this but I would be wary of the wheel hop, hate to see you toast the diff!

The other thing that concerns me about the Rotrex units is the internal transmission temps with extended use at high rpm. But that probably wouldn't be an issue unless you are flogging it for several hundred miles on a circuit.

The Rotrex style with comparable pump capacity is going to be more efficient across the board though. That means more boost on gasoline.

I have found that while there are some wild outliers every once in a while most setups I've come across liked boost more than timing on normal gas.

 

It because of the way boost is built on the Sprintex style S/C that I would use a Turbo as well to "twincharge" a Fit:


Edit: This is a 1.4L gas 4 cyl.

You could do it with a Rotrex too, tuning would be an adventure though. Not that the other way would be a walk in the park.

 

The little under hood I/C is said to have less pressure drop that the front mount they were trying... It sure seems to boost more quickly than the graph shows.. The Rotrex can spin safely at 28000 and on the kits they keep it down around 18000 or 20000... The high boost kit is quite a bit stronger at 1/3 or less throttle from 4500 RPM up than the the 5PSI base kit at the same revs. My IATs are way high after a WOT romp in 5th but I think it has to do with what I told you about the upward flow of heated air from the radiator caused by the louvers since it runs coolest at 40 to 50 with light throttle... I have checked the traction oil temperature by touch after it exits the cooler in front of the radiator after a hard run and it is not anywhere near being hot... I know it would be hotter straight from the blower but the little cooler couldn't bring it down as low as it is if it was dangerously HOT hot. I have 400 tread wear compound tire with a very open tread.. I did have all season performance tires with 320 compound and lots of surface contact... They were better on smooth concrete and very worn asphalt but neither hop unless the tire pressure is hyper miler high. You just have to compromise on some things or die in the poor house... I am kind of like you and prefer to put the go pedal down after I am moving. That 0 to 60 stuff is too costly, wears out clutches, destroys drive trains, and bends connecting rods.... Oh I forgot bending frames and snapping rear control arms.

 

The twin screw has to be the way to go on that type of setup... I just had a flash in my head of a tweaked VW TDI or Audi diesel powered Lotus kit car... Where do this kind of insanity come from?

 

WELL, I guess I DEFINITELY won't be getting an S/C. Not with the way I was driving after work...

As DSM knows, it just snowed earlier. I took a curve a little too fast and realized too late to slow down. In my STUPIDITY, I thought I could power the front wheels through enough of the turn to avoid the curb.

NOPE.

I now have a good gouge along half of the lip of the front passenger wheel. Oh... not to mention any possible damage to the axle too.

So yeah... adding an S/C to my stupidity is probably not a good idea.