Twin Turbo/Supercharged STI

[kimokalihi]

http://www.forcedairtechnologies.com/

[Lunatech]

DAMN!! I bet that gets the old heart pumpin'!

[kimokalihi]

Yeah I bet it does too. Unfortunately that site doesn't show any specs. Lame. It says coming soon but those pictures are dated 2005!

There's also another WRX that has a single turbo and supercharger and also some custom manifolds including dual manifolds with a supercharger in between and then another manifold with the supercharger built into the manifold. Looks pretty cool. I wonder what kind of boost they run.

[kimokalihi]

This one has a couple videos.

Guy says it's a supercharger from a mercedes benz and it runs up to 12psi until the turbocharger kicks in and then the electric clutch disengages the supercharger to relieve parasitic draw and the turbo goes up to 24 psi creating 437whp on 100octane fuel. Says it was on another 04 STI that ran 11 sec flat quarter mile times. He also says the turbo doesn't kick in until 4500 rpm and you can turn the supercharger off I believe and he claims to get 26mpg just driving around. Says he used to get 250miles per tank and now gets 380miles on a tank of gas!

[n2x4]

Says he used to get 250miles per tank and now gets 380miles on a tank of gas!

And that it takes him 5 hours to change the spark plugs

In all seriousness though, that's some impressive stuff!

[kimokalihi]

Yeah that's a little too complicated and crammed in there for me.

[Legacy777]

Forced air makes some crazy shit!

They did Rod Grossvner's setup a few years back.

[magicmike]

and what is the point of this exactly? when I see this stuff I think of this.




I mean its not like you are going to sell that shit to anyone...

[evolutionmovement]

LOL! But it is an interesting exercise in pointlessness. I feel that way about most "Max Power" methods of performance, but at least this is something different. Sort of. Which also means expensive.

[jamal]

that also has to be a nightmare to tune. There's no way that maf is going to read right on the twin turbo car. I'd assume it's on a standalone using speed density, but still, that would be a clusterfuck to deal with.

I had a simple rotated 35R that wouldn't even idle because the maf was too close to the turbo inlet.

[kimokalihi]

That's the MAF correct? That is quite close to the turbos.

[gijonas]

Ive been looking for a nice simple lightweight power option,i bet its reliable as a bell too!

[kimokalihi]

As reliable as they come, almost like it was a factory option. You know it's reliable because the guy said it's his daily driver.

[magicmike]

As reliable as they come, almost like it was a factory option. You know it's reliable because the guy said it's his daily driver.

I would hope your "daily driver" was good enough to use daily after you dropped about 20k on it which is what this is at least I'm sure.

[Smithcraft]

I am totally envious!

But I would never, ever, want to change those plugs!

SC

[kimokalihi]

Yeah but with this new prototype they're working on it probably won't be bad.

[evolutionmovement]

I'd rather build something for less that gets triple the mileage with less than half the power, is cheap and reliable as death to run, handles better, and is almost as fast.

I always find it a shame that people with skills and money to waste so seldom have any vision. Cue everything from dozens of still-born derivative supercars to the Neon on a jacked up 4x4 chassis I saw the other day.

[kimokalihi]

Triple the gas milage? 78mpg! I'd like to drive that kind of car regardless of how much power it has. Shit I drive a 3 cylinder now that's gutless and only gets 38mpg.

[Legacy777]

Sometimes it's a matter as to whether it can be done or not....

[evolutionmovement]

Alright, maybe not quite triple, but over 60 mpg with the performance I think I need to sell the idea to people. Light weight and aerodynamics. Cars are designed stupid because of the boring people who are into them, conservative apathetic regular consumers, and government intervention. I'm building this car for me, not anyone else. What are the compromises? Only 2 seats, and that a 1+1 really, tandem, and only a woman in the back (don't want some dude's legs alongside my seat), poor luggage capacity, some reduction in safety, and you get more wet when you enter or leave in the rain (no doors—a sliding canopy like a fighter plane. Allows for a much stronger, safer chassis, easier engineering, lighter weight, no structural compromise for open-roof driving in nice weather, and it looks cool). Probably not something for heavy snow, either, but not many performance cars are. 95% of the time I drive alone so why haul around 3000 lbs. or more of brick-like car for that? Still, I realize it's not for everyone and it's requiring a rethink of almost everything, though I've been perfecting the concept since I was in design school. This could take a while, even outsourcing the chassis build. I wish I had the money these guys have to throw away.

[mike-tracy]

Triple the gas milage? 78mpg! I'd like to drive that kind of car regardless of how much power it has. Shit I drive a 3 cylinder now that's gutless and only gets 38mpg.

I'm sorry. My old Corolla got 35-38 mixed, and somehow my dad got 45mpg. Hell no matter how I beat on it I couldn't get under 30! And I had 4 cyls with Vtech, Yo! (ok VVti)

Haven't ever got 30 in a Suby, my best is 29 with crazy hypermiling in my 96 Legacy. That was on my many trips from Seattle to Mountain Home, ID and back.

[206er]

Since those are obviously big budget builds i don't know why they wouldnt go with a centrifugal charger instead of the roots type which is much less efficient and blows hotter air.

[evolutionmovement]

Oh, and Kimo, have you seem the Aerocivic? www.aerocivic.com. A few hundred bucks and an old Civic = 90 mpg.

[kimokalihi]

Nope. Is the horrible looking back end required? He could have done a nicer job with it, it looks haggard but I guess it serves it's purpose.

I wonder what kind of difference it would make to do everything but the long pointed back end? I've seen several people close up the wheel wells and the front bumper on their metro and get rid of the side mirrors or run low profile ones and hypermill their way to pretty good gas milage. Along with weight reduction and other aerodynamic things.

Would it help to make the bottom of the car more streamlined? Cover up the drivetrain and suspension as much as possible with aluminum or sheetmetal?

[evolutionmovement]

He definitely could have made it smoother, but he doesn't care. Also, the very back could maybe be truncated into a Kammback for similar or a little better performance (probably not quantifiable) since the taper beyond 50% of the maximum cross section of the vehicle creates more skin drag, but that's not a huge source of drag on a car, so it would more benefit by reducing the length and maybe better adhering to traditional ideas on what a car should look like (ideas which are wrong—they date to a ling-ago day when cars were designed to resemble trains, a symbol of speed and power back then, not intelligent efficiency born of necessity like that of an aircraft).

The back is more important than the front. The cut off all cars have, which is why most are stupid, creates wake drag. Run your hand horizontally through water while holding it vertically. Feel the drag, maybe see the swirling water turbulence following your hand. Now try it holding your hand horizontally. I'm sure you don't actually have to try this to know the difference. Ever draft a tractor trailer? That low pressure zone that makes it easier for your car comes at the expense of the truck (although, in theory, drafting him helps reduce some of his turbulence, don't expect the driver or a cop to care). It's like a giant vacuum cleaner constantly pulling it back, requiring more power to move through the air. The truck's shape serves a purpose of utility, though around an open taper off the back of the trailer has been tested in Europe to improve mileage by up to 7.5%: http://green.autoblog.com/2009/11/13/co ... -trailers/ which is a big deal on tractor trailers and would likely make a larger percentage improvement on cars due to a lesser rolling resistance.

There are simple ways to improve aero, several of which I'm doing to the wagon, though none will do as much as greatly reducing the wake turbulence with a boattail, the point is to keep the storage useful and not have it be 20 feet long.

Cleaning up the undercarriage, especially where many stupid cars have the rear bumper hanging down in the air stream like a parachute. Lowering can reduce the benefits of cleaning this up, but lowering does reduce frontal area a little, which helps. Which is of more benefit would probably require a wind tunnel to know, but I fall on the side of stock height and cleaner underbody (but I also like to be able to drive over sidewalks and islands when necessary).

Engine compartment turbulence reduction. Combined with an underbody cover, sealing the engine compartment off from air flow by ducting the exhaust air from the radiator into a low pressure zone reduces drag (and lift from the build up of higher pressure) from the engine and components, which improves cooling as well. I'm using the space behind the leading edge of the hood for the air exit, much like the rally cars use. On my prototypes, I'll be ducting it out the sides through something resembling gills on a shark (the resemblance goes with the vehicle being reminiscent of both a Great White and a Curtis P-40).

Blocking off the upper grille. Not only is it unnecessary for cooling and increases drag, but combined with the ducting, should increase cooling efficiency to block off. If you look at the speed record Legacys, they also do this. Many things done on speed record cars are useful as drag reduction helps top speed as well as mileage.

Covering the wheels or getting flat wheel covers. I'm not going to do this, though I might test a partial skirt on the rear, which isn't usually a huge help, but depends on the vehicle. Covering the front, making them wide enough to allow the front wheels to turn, would be more of a PITA, and be difficult to integrate into the body design so it wouldn't look strange. On my prototype, they will be enclosed in enlarged Cessna 172 wheel pants since they are separate from the body like a single-seat race car. Because the whole vehicle looks like an old fighter plane, the wheel pants will appear to fit because people are used to associating covered wheels with aircraft fuselages. At the least, the wheel covers won't stand out as being particularly strange compared to the rest of the thing.

A rear spoiler, when located or angled property can help. I'll be adding a rear spoiler and angling it down at 12 degrees to reduce wake turbulence a little. On a sedan, depending on the angle from the roof to the end of the trunk, a wing could help airflow off the roof reattach in a smoother manner than it would without the wing, reducing wake turbulence which could otherwise be almost as bad as a wagon. This is why the Civic Hybrid has a small lip spoiler.

Replacing mirrors with cameras would be nice if the law ever catches up to technology. What about low-drag mirrors? Because they look low drag doesn't necessarily mean they are (or they aren't), but they're generally less useful in terms of visibility and since they still create drag, I'm personally not interested in doing anything with them until cameras are legalized. The Aerocivic gets around the law by mounting mirrors on the inside, which is technically legal (may vary by state), but I question the usefulness.