Stealth / Performance Exhaust System Hybrid
 

The Geo Metro 1.0L generally brings fuel economy to your mind first, and last of all it brings performance. However, I think these little things have potential! I mean, the Suzuki Swift with the 1.3L engine (same engine the 1.3L Metro uses) can have up to 450HP after spending thousands of dollars on engine upgrade, exhaust upgrades, intake upgrades, turbocharger kits, etc. The 1.0L might not have as much potential as the 1.3L but it still can manage more than the measly 49-55HP it puts out.

So, let me introduce a simple concept I thought up. After seeing some interesting exhaust cut-outs on the Speed Channel I spent some time thinking this system up. It would allow a "stealth" mode that would be very quiet for those long higher trips or when your sneaking around at night. However, at the flip of a switch you can switch over to a turbocharger with nothing more than a straight-flow muffler in the exhaust system.

An interesting thing side-feature is the ability to adjust the cut-outs to different partially open positions. Thus you could change your backpressure on the fly.

Let me know what you guys think, and leave any suggestions. Perhaps I should rearrange the set-up of resonators and catalytic converter? Maybe I should go with smaller resonators? I choice these because Vibrant and Walker are supposedly some of the quietest systems out there. I added the Aero resonator just because I wanted two resonators but didn't want to pay the price of two Vibrants. Also, I have trouble finding small resonators other than the stock kind at Advanced Auto Parts.

Sorry about the size. This is as big as I can get it with Photobucket. If you save it and zoom in on it you should be able to real everything fine.
https://www.fuelly.com/attachments/fo...0f11dd9a9f.jpg

Years ago I remember JC Whitney used to sell exhaust valves to switch between 2 separate exhaust systems. It was remotely operated by a cable that was installed where the driver can reach it. Don't know if that kind of stuff is legal anymore though.

-Jay

Elecric cutouts are pretty easy to find with google.

Sorry about the small pictures guys, I tried uploading a bigger one but now every time I try to upload something to photobucket my Internet Explorer or Firefox crashes. I'll upload a better one later once it starts working.

I'd assume the stuff is legal. I don't think there are any laws saying what kind of exhaust you can have on your car (if its not in use). You could probably have your gas tank filled up with leaded gasoline with extra lead substitute or even have your diesel tank filled up with farm diesel and not get in trouble for it as long as you were running legal gas from a different tank on the vehicle.
Besides, if you get pulled over and just make sure your switched to your legal set-up and if the officer asks be sure to say the other exhaust is for track use or off road use only.

How is the intake air going to get into the engine when you're switched to a non-turbo exhaust?

What are you going to do for engine management?

I plan to replace my crappy custom exhaust with a quiet version. I can fit two long resonators on a straight portion of the pipe. The whole exhaust will still be straight-through Magnaflow brand components and mandrel bends. There really is no reason to restrict the exhaust.

https://www.jcwhitney.com/wcsstore/jc...1440G_SW_1.jpg
There's an electric one.

If you go to jcwhitney.com and search "exhaust cutout" they have 4 or 5 others. You might be able to use one of them

I'd use a similar set-up for the intake. Use electric cut-outs to switch between a normal intake and an intake with a turbo in it.

As for engine management, I haven't thought up anything that would be really reliable. I thought I could use a EFIE and when I turn the turbo on I can turn the EFIE so that it runs rich. As for timing? Well, its a distributor ignition so nothing the computer can control. I suppose I could play around and find an ideal point where it wouldn't detonate with the turbo and it'd still run reliably when the turbo was off (at the cost of fuel economy of course.)

I could always get a Haltech E6X Programmable Fuel Injection Computer and get some parts to convert it to computer controlled ignition. (I'm pretty sure you can order all the parts for that from the Suzuki Racing Development website.) Then I could tune it for the turbo, and possibly still keep an EFIE in to lean it out quickly. Otherwise, I could integrate a laptop under the seat and possibly a touchscreen into the dash so I could just change all the parameters on demand, possibly put in some presets on the program if thats possible.

Of course it'd cost fuel economy for the added weight and such, but it'd just be a fun project if you have the money for it. We all have those times when we're driven our car for fuel economy but you just can't resist flooring it once in a long while just for fun. Usually you end up disappointed (I know I've been once I rode in my cousin's Roush Stage 3 Mustang and then I went back to my car.) This project would just be something for fun so you could get good fuel economy, but also have power on demand if you get the urge and you don't have to drive all the way back home to get your other car out of the garage.

If properly sized, the turbine shouldn't impose enough of an exhaust restriction during cruise to warrant an elaborate exhaust cutout / bypass setup.

FWIW, I have an old thunderbird turbocoupe (see https://www.dragtimes.com/Ford-Thunde...slip-2618.html ) that still knocks down low 30's MPG on the highway if you stay out of the boost.

John, you might also ask over at www.grassrootsmotorsports.com

At least in California, they weren't legal even then!