Boosting the Mirage

[AScoda]

Ahem....BEWST

[Loren]

Well, first I need to get control of FEWL.

[Loren]

Hmmm...

If I do an add-on injector at or near the throttle body... I can control that with a Megasquirt 1. The MS1 is pretty limited in what it can do, but it was designed as a Fuel Only system. (that's why Megasquirt was called "Megasquirt" in the first place... it was fuel injection and nothing else!) Pretty old school as far as MS goes, and it's pretty darned cheap. I can get an MS1 kit for under $200. To to basic throttle body injection, the only inputs it needs are MAP (which is built into the MS1) and a tach signal. With that, I should be able to tap into the stock fuel rail feed line and run a standard injector somewhere. For maybe $250, I'd have a fully tunable auxiliary fuel injector that would solve all of my fueling problems.

[Native]

Simplify and add lightness.

[Loren]

Now you're sounding like my wife. "But, won't a supercharger add weight?"

[mymomswagon]

Simplify and add lightness.

those front calipers and rotors are heavy. Get rid of them!

[twistedwankel]

The #1 lightest USA available car is the Mirage by a lot.
I looked it up. Google 20 lightest cars.

I personally love the Alfa Romeo C4 but it's $55K new and it still weighs more than a Mirage even with a carbon fiber chassis.

[twistedwankel]

What about a turbo located at the rear of the car exhaust? See that often now.

[Loren]

I'm sure there are reasons why a person would choose to mount a turbo at the rear of the exhaust on a compact, lightweight FWD car and then run 20 feet of hose back up to the intake. But, I can't think of any.

[twistedwankel]

20ft?

[lddavis91]

I'm sure there are reasons why a person would choose to mount a turbo at the rear of the exhaust on a compact, lightweight FWD car and then run 20 feet of hose back up to the intake. But, I can't think of any.

Well, it works towards better weight distribution and the piping itself acts as something of an intercooler.

[Rawkkrawler]

I'm sure there are reasons why a person would choose to mount a turbo at the rear of the exhaust on a compact, lightweight FWD car and then run 20 feet of hose back up to the intake. But, I can't think of any.

Well, it works towards better weight distribution and the piping itself acts as something of an intercooler.

And replaces the muffler.

[Loren]

Well, as much as I like me a good Megasquirt project... I think I've decided to pay the bucks and give the Unichip G4 a try. I just like all of the things that it can do that the MS can't, and being able to do all of the tuning that I need to do WITHOUT adding more hardware (other than the supercharger itself) is a good thing.

Gotta get my taxes done first. Once I'm sure I'm ahead of that situation... I'm gonna order the G4 and install it first. It's very possible (likely, even) that I can tune it to maximize the power output of the mods that I've already done.

[twistedwankel]

Gotta get my taxes done first.

I don't earn any money. What are these taxes you speak of? Real Estate?

[Carracer]

The only thing I can add is can the Mirage clutch and CV axles take the power? I know it isn't much added HP but I remember you mentioning that the old clutch had some odd wear on the springs.

[Loren]

I'm not 100% sure about THIS transmission, but I know the Mirage CVT is the same one used in the Nissan Versa and other cars with engines pushing 100-120 hp. Odds are good that the manual transmission is also an off-the-shelf unit that can handle something more than 70-80 hp. Not too worried about it.

The clutch... yeah, I expect similar spring problems down the line. Though I didn't use a factory clutch disk the second time. It might be slightly improved? If it breaks, I'll just have a custom clutch disk made. There's a clutch shop over in Tampa.

Axles should be fine for what I'm looking at. I really don't see me pushing more than 95 hp.

The beauty of it all is that it's a really easy car to work on, and used parts are plentiful and cheap. If I break a transmission, I can get a new one for probably $200. Axles, $50-100 a pop all day long. Engines... as I've learned, $300-700. I'm not TRYING to break the car... but, it's an acceptable risk.

[Tim_M]

Ran across an eerily similar power booster at the Mercedes Museum.





It did sound cool when you hand cranked it as fast as you could!

I'd skip the restrictor (which seems contradictory) and control the psi with the pulley...hopefully for something more than ~5 psi to realize a return on the investment. I don't recall, but you might consider switching to E85 greatly increases your performance potential and safety margin.

Didn't say anything 'wrong' with your tuning process (albeit time consuming), but getting numbers for a baseline to ensure your current combo is healthy and another for factual improvements lends credibility to the project.

Of course, we didn't follow that process with my son's M3 project due to scheduling issues - 200 WHP was very standard for the S52 looking at the dyno run history and the resultant 140 WHP increase with the V8 is a great data point (some still argue, not worth the effort unless you at least double the HP for the engine swap investment! )

[Loren]

Ran across an eerily similar power booster at the Mercedes Museum.

That's pretty cool! So much of our automotive technology is truly ancient, especially anything that's purely mechanical.

I'd skip the restrictor (which seems contradictory) and control the psi with the pulley...hopefully for something more than ~5 psi to realize a return on the investment. I don't recall, but you might consider switching to E85 greatly increases your performance potential and safety margin.

I was thinking restrictor plate at least during tuning because it's a LOT easier to do (and cheaper) than swapping pulleys. If I found that I had to run a big restriction, then swapping the pulley would be the way to go.

And since I've decided to go ahead and put fuel management on the car, I don't have to stick with that 3 psi restriction. I can run more like 4-5, which should be right about where this SC naturally ends up.

Didn't say anything 'wrong' with your tuning process (albeit time consuming), but getting numbers for a baseline to ensure your current combo is healthy and another for factual improvements lends credibility to the project.

I got nothing but time. Trying to minimize the expense.

Still waiting on taxes...

[blacksheep-1]

can you do a basic explanation of the megasquirt? is it an additional injector? or can you use it to run an entire engine, also where does it get a reference from? the gas pedal or some type of air meter?

[Loren]

can you do a basic explanation of the megasquirt? is it an additional injector? or can you use it to run an entire engine, also where does it get a reference from? the gas pedal or some type of air meter?

Megasquirt is a complete aftermarket ECU. It gives you complete control over the fuel injectors and ignition timing, as well as idle control, and other things like cooling fans, etc. It's extremely configurable, can run anything from 1 to 12 cylinders with just about any kind of ignition system.

Absolute most basic inputs would be crankshaft position, coolant and intake temperatures, and manifold pressure. With that, you could do at least rudimentary control of fuel and spark.

Adding a camshaft position sensor adds to the accuracy, and would allow for finer control and the ability to do sequential injection (rather than batch fire) and sequential spark (rather than wasted spark).

Adding a throttle position sensor makes it a lot easier to control things like idle speed and acceleration enrichment.

It's capable of doing MAF input, but people just use MAP.

It also has the option of a speed input, which could be used for traction control and such.

It's a very flexible system.

What I was thinking of doing with it here was just controlling an extra injector when under boost rather than messing with the stock systems. But, it's capable of much more than that.