Beyond Bolt On - The Cheap Road

[benjpi]

There's a really great thread here on the forum, where the gauntlet has been thrown down for those interested in building a beast of an NA motor: The goal of 100 hp per liter of displacement. These engines are thrilling to drive, and the sound they produce at idle is enough to make the hairs on the back of your neck stand up. At least if you're a motorhead they do.

However, as great as these engines are the rest of us have to live in the real world. We need to worry about things like emissions inspections, daily driveability, and the almighty cash flow. The fabulousness of AutoEXE stainless steel long tube headers is great, but eliminating the first cat along with the dear price tag pushes that upgrade out of reach of the cheap-ass enthusiast. Likewise with Haltech engine management systems, or even the legendary Twiggy camshafts.

There is an easy solution here for those who just want more power and don't want to tinker around: GET A TURBO. For Otto's sake, Mazda provides every bit you need to get started and the upgrade path is clear. The horsepower you can make from this move is limited only by your wallet (and your interest in changing crankshafts). With some careful purchases & hoarding, you too can get at least the 170 hp that Mazda claimed for the Mazdaspeed Protege while meeting emissions in just about every state in the union. (I'll get no more specific than that, emissions laws are byzantine & give me a headache.)

IF though you are the type who likes to tinker and are interested in non-conventional solutions, this thread is for you. Engines respond to change. It's finding the RIGHT changes to make that will get you past the Intake/Muffler changes made to so many cars. In my next few posts, I'll lay out a bit more of the intended direction.

 

[benjpi]

First up: the MP3 ECU upgrade. Due to the efforts of those on this board, this upgrade is readily available to those that read the For Sale thread (and can use the search function....) From my feeble understanding, this upgrade offers the following: about 3 WHP. Seem weak? Try pulling back against three horses sometime. This upgrade seems to be the next best upgrade after the standard intake & muffler upgrades, and given the current going cost is a pretty cheap upgrade too. No check engine light, no rewiring. You will need to change to premium fuel to get the most of this upgrade though.

What does it do? Beats me, I can't read or write code to save my life. From what I've read here, it does this: advances the timing and modifies the fuel curve a touch. The other thing that it does is eliminate the VCTS system. What's that, you say?

Okay. VCTS in a nutshell: it is a set of butterfly valves setup at the end of the intake runners, just before the intake ports on the cylinder head. The butterfly valve is not "complete", in that when it is fully closed it doesn't completely block the intake runner. There is a small cutout in the valve that allows some air to flow around the butterfly when it is closed. Why? The air velocity through that very small hole at cold start conditions causes turbulence in the intake charge during cold starting. That turbulence increases the efficiency of cold-start combustion and lowers your emissions during the first few minutes of engine operation. Once the car is warmed up, these butterflies fully open and only present a minor restriction to the intake flow.

In the interest of getting a bit more HP from the FSDE, Mazda decided for the MP3 to eliminate the VCTS setup. You see, even when it is fully open it STILL is an additional restriction to intake flow. The elimination of those OPEN butterflies is part of the 10 hp that Mazda posts between the regular 2.0 FSDE (130HP) and the MP3 (140 HP). It's an OEM solution that WILL produce a result.

 

[benjpi]

Next up: The J-spec camshafts. Again, my feeble understanding is offered waiting for correction from those who are able.

In other countries than the US, the FSDE engine was offered with an upgraded INTAKE camshaft. This is commonly called the J-spec or Mazdaspeed Intake cam. These are readily available from more than a few sponsors. Here's the trick though: It doesn't really seem to offer much. There are claims of 10 WHP from the intake cam, but there is also evidence that the real number might be lower. I'm not going to tread across that field of crap, but suffice it to say that this cam DOES offer a measureable increase in engine performance. I have one of these in the basement just waiting for a timing belt change.

The EXHAUST cam is a similar story. What EXACTLY do you get from this? Hard to say, for me at least. The "JDM" exhaust cam as I understand it is a re-pinned ( or re-timed) INTAKE cam from the FSZE. It offers a bit more lift & duration as compared to stock FSDE cams. I believe it is the same lift/duration as the JDM (FSZE) intake cam but with its gear adjusted to work as an exhaust cam.

I really don't know if these two upgrades will pass the emissions gestapos. The intake is mild enough to be an OEM offering, and the exhaust application doesn't seem to be any worse. In the interest of science, I plan this very upgrade (both cams) in the near future. I'll keep you posted on the results, but because I like to talk about engines I'll blab on...

 

[benjpi]

Compression ratio. WTF is that? The compression ratio of an engine is a ratio of volumes. At top dead center, the piston gets Pretty Damn Close to the cylinder head. The amount of air trapped at TDC during combustion is the combustion chamber volume. In addition to that, there is the swept volume of the engine. That is the volume displaced by a piston over the stroke of the engine. What this means, simply: If you take the engine bore and do the pi-r-squared thing to get an area, then multipy it by the engine stroke, you have the swept volume. Getting combustion chamber volume is trickier, unless you're willing to accept some error.

The right way to get combustion chamber volume is by actual measurement. There's a lot of methods to do that, but they are for the patient and skilled. For the impatient, there's an estimate available. If you know the engine's RATED compression ratio AND you know it's swept volume, you can use those to calculate the combustion chamber volume. It's just algebra at this point:

Compression ratio = (swept volume + combustion chamber volume)/combustion chamber volume.

Why change compression ratio? Simple - it increases the efficiency of the Otto cycle. Without dropping too many goofy words like enthalpy, I'll try to explain. Raising compression ratio increases the combustion efficiency. The peak pressure in the cylinder achieved during combustion is a function of the amount of compression BEFORE combustion. As the CR is increased, the cycle efficiency increases and correspondingly produces additional power. Take a look at the attached link, if you really want to know:

http://www.qrg.northwestern.edu/thermo/design-library/otto/otto.html

There are plenty more links available for the curious. They all basically say the same thing: more compression equals more power. Now before I get shouted down, there are some caveats to raising compression:

1. It will increase the engine's sensitivity to knock.
2. It might require changes to engine timing, and not always the way you'd expect.

There is a reason that the OEM's don't just deliver every engine at 13:1CR. At those compression ratios, strange things start to happen during the compression stroke and the early micro-seconds of combustion. The intake charge heats up during compression, and if the compression is high enough it can actually get hot enough to light off the fuel. Even if that doesn't happen, once the spark sets off the initial charge, the instant change in pressure in the chamber can cause fuel/air mix in the corners of the chamber to ignite AT THE SAME TIME. Either of those occurences can produce disastrous explosions in the combustion chamber that will tear the engine apart.

There are many tricks that have been developed over time to reduce engine's sensitivity to raising CR. These have included such fun things as squish bands, reduced included angles between intake & exhaust valves, compact combustion chambers, and direct injection. While all fun theory, WHAT THE HELL DOES THIS HAVE TO DO WITH CHEAP PERFORMANCE?

Simple. Again, drawing from Mazda's own upgrade path for the FSDE to get to the FSZE. The FSDE has a 9:1 compression ratio, but the FSZE has 10.4:1. Mazda does that by delivering the FSZE with domed pistons. That increase in ratio is a crucial part in the increase in performance from FSDE 130 HP to FSZE 170 HP.

Now if your block is shot, and you need a new set of pistons, the FSZE pistons seems like a no-brainer upgrade. But I can't say if they play nicely with US-spec OBDII combuters. Maybe others do.

Another option to increase CR is to mill the cylinder head. This again has its own risks, but a trip to the junkyard and a bit of time & money might possibly be able to produce similar results.

Tired, more later. Looking forward to hearing from others who've done the work or are interested in doing so.

 

[09WhiteBlackAzz]

great post!

 

[HKPRO5]

Sub!! Love the info

thanks!

 

[AzteCypher]

Interesting... keep writing.

 

[LordWorm]

Nice thread...

biggest limitation on our motors though (at least until you start wanting power forces you to do abnormal things), is the ECU... thats the killer.

Twilightprotege had 150hp on his, with bolt ons... but the critical bolt on was the ECU....(and cams of course).

You can make the cars quite peppy with just I.H.E though. But once you put an aftermarket computer on them, it becomes a different world.


shame there are no real affordable options

 

[ghostbusters]

the emanagae blue piggyback wont do? i'm getting a stage 2 head job done, will and emanage blue suffice?

 

[TWISFM]

Awesome sauce

 

[LordWorm]

I have no experience with the emanage blue... i believe someone here in australia got one to work though...