So you want to be a tuner, Part III

[537]

Hi!

Once again I'm back to bring about awareness to the masses. In my previous article (Part II), we briefly went over some items that can be checked off in order to improve upon a vehicle's maneuverability and driver comfort. We went over certain aspects of handling and how to negate some of their shortcomings, including braking and suspension. Today, we're going to cover the meat of the tuning industry. That's right, folks. We're going to focus on obtaining more power!

Before getting to the nitty gritty, I feel it necessary to conduct a crash course in gasoline engine dynamics and design. With that being said, let's get it started!

a. Combustion Engine Theory

For all intents and purposes, we will be focusing on gasoline combustion engines for this article.

All gasoline internal combustion engines rely on four things. Oxygen(air), Fuel, Compression, and Ignition. With the correct mixture of the above a controlled detonation results in a powerful source of energy used to conduct work. Straight from the factory, a vehicle is designed to stay environmentally friendly, yet offer adequate power. It is, in essence, the detonation that tuners attempt to modify, partially or completely stemming from changing the mixture of the above variables. The following sections will give a little more detail in this regard, appropriate to the type of engine it references.

b. Engine design

Gasoline Internal Combustion Engines (which this article will focus on because the majority of road/race vehicles are of this type!) can be roughly classified into two categories. Not surprisingly, there are differing schools of thought as to which is the better design. They are:

• Conventional Piston
• Rotary

Both types of engines rely on the four things indicated in Combustion Engine Theory, however approach that realization using different terms. For ease of use and for simplicity's sake, we will be approaching Stage I power modifications for these two engine types the same. It is not until you further desire more power that the avenues to do such take on different paths.

Outlined in the previous section was a term I referenced as the correct mixture of Oxygen, Fuel, Compression, and Ignition. One thing that is for sure is that automobile engineers have completed their due diligence and maintain this mixture for longevity and economical purposes. Once you modify this to deviate from OEM specifications, you can quickly deteriorate or worse yet, destroy an engine. An example of this disastrous condition would be increasing the amount of oxygen and not adding appropriate amounts of fuel to the mixture, therefore creating what is called a fuel lean condition. This generates additional heat, leads to premature detonation, and causes engine knock. This is the number one cause of melted pistons/broken rods/broken piston rings. For that reason alone, we'll be attempting to stay as true to the factory specified ratios of Air and Fuel as possible for these Stage I modifications.

If that didn't scare you into reading no further, that's great news! Nowadays, automobile engineers have also built into the vast majority of vehicles, something called a Mass Air Sensor (or air mass sensor/air density probe, etc.). This sensor takes active readings about the air such as air temperature, velocity, humidity, and altitude to determine how much oxygen the engine is about to see. This information is then sent to the vehicle's ECU where a decision is made about how much fuel is needed to create the proper air/fuel ratio. From that point, a signal is sent to the vehicle's fuel delivery system detailing how much gasoline its injectors shall inject into the cylinders, where that mass of air awaits the engine's compression cycle/stroke (physics buffs will note that combustion occurs much more easily and with more force while fuels/oxygen are pressurized). At the designated point of proper compression, the ECU then sends a signal to the engine's ignition coils to light a spark, igniting the pressurized mixture. The gases produced from the combustion are then expelled via an engines exhaust ports and eventually end up in the atmosphere via your vehicle's tailpipe. This contained explosion is the heart of all internal combustion engines, and is the singular driving force at work which ultimately propels your vehicle. Now this is an extremely high-level explanation of what goes on under your hood. But enough of this techno-babble, anyhow. Let's get on to what we're here for.

It is because of a vehicle's Mass Air Sensor (or its equivalents) that we are able to modify the amount of air the engine will 'breathe', yet maintain the proper air/fuel ratio required to keep everything in good working condition. Which leads us to....

c. Part III, Stage II modifications -- Improving Power!

Improving a vehicle's 'breathing' capability is the one thing that tuners look to first to create more horsepower (Turbos, superchargers, nitrous, etc are all related to this, but remember, we're taking baby steps here!). In the tuning world, initial improvements can be made without manually modifying fuel delivery, adding ignition power, or changing compression. An engine's breathing capability can be closely tied to three components, which are:

• 'Intake' (Air Intake)
• 'Header' (Exhaust Header)
• 'Exhaust' (Cat-back Exhaust)

The Intake is where air is drawn into the engine through an air cleaning element. Typically this air cleaner is housed inside a restrictive plastic housing which serves two purposes...to silence the sound of the engine as you step on the accelerator, as well as keep it isolated from the intense high temperatures that live under the hood. Performance can be freed by installing a high quality air cleaner that is less restrictive, as well as using proper tubing to relocate it away from the engine bay. Intake systems such as these can be referenced as 'Cold Air Intakes'. Be careful of those CAI systems that relocate the filter too close to the ground, as this can spell bad news if ever submerged in water (or any liquid for that matter). If your engine breathes in water, it will become hydrolocked and will, quite literally, drown. Quality CAI systems provide a type of bypass valve to prevent this situation. Look for a CARB EO number stating that it is legal to use on public highways.

The next step to freeing up an engine's breathing capability is by improving upon its exhaust header assembly. Now before you turbocharged drivers get your panties all up in a bunch, remember your exhaust manifold is also an exhaust header, but there's just so much you can do to that. We'll get to that in another article, shall we? Anyhow, installing a properly designed header will grant you even more breathing capability. Look for one that bolts directly up to the OEM catalytic converter if your vehicle is a street car, and look for one that completely replaces the catalytic converter if your vehicle is a race vehicle. Look for a CARB EO number stating that it is legal to use on public highways.

The last step in this installation is to install an aftermarket Exhaust system. More commonly known as a 'Cat-back', exhaust systems usually consist of a free flowing muffler, and piping to hook up to an OEM catalytic converter. Quality systems are lightweight, are engineered out of durable long lasting materials (of which the more expensive ones are constructed out of Magnesium or Titanium, or an alloy of both), and brag about boasting a throatier, deeper growl. Make no mistake, noise does NOT equate to power, so do your research carefully and search for a proper flowing system that will compliment your vehicle. Look for a CARB EO number stating that it is legal to use on public highways.

With these components explained, I do have to say that they work together in the equation, and installing just an intake or header or exhaust will most likely waste your time. If you are looking for any type of gain, the three components really need to be chosen carefully to work with each other.


That about does it for this article, please stay tuned for my next article which will look even further into creating more horsepower, as well as further improving handling and brakes!

[deez nuts]

i need to print all these out and sit in my car and do a step by step.

slightly off topic question: but what do you all think about that supposed IS300 chip that boosts the horsepower to around 400?

[lethal]

Great read, 537. Excellent work.

[537]

Originally Posted by Chasiubao_Boy

slightly off topic question: but what do you all think about that supposed IS300 chip that boosts the horsepower to around 400?

Do you know the company name that programs this chip?

[deez nuts]

Originally Posted by 537

Do you know the company name that programs this chip?

no i haven't really done any research on it.

i've just heard it from friends and co-worklers that it's out there.

i just wanna get an opinion on it from people that know about working on cars; rather than getting inputs from co-workers that buy a 350z, G35 coupe, an evo or a wrx sti, tint their windows and think it's working on their car and claim to know what they're doing. they keep asking me why i bought my car when i could've bought their car for around the same price and why i don't put the chip in my car.

i'm just more curious than anything else and maybe i'll consider doing it if later on down the line if i had the right input from people that know their shit.

[537]

Originally Posted by Chasiubao_Boy

no i haven't really done any research on it.

i've just heard it from friends and co-worklers that it's out there.

i just wanna get an opinion on it from people that know about working on cars; rather than getting inputs from co-workers that buy a 350z, G35 coupe, an evo or a wrx sti, tint their windows and think it's working on their car and claim to know what they're doing. they keep asking me why i bought my car when i could've bought their car for around the same price and why i don't put the chip in my car.

i'm just more curious than anything else and maybe i'll consider doing it if later on down the line if i had the right input from people that know their shit.

What it boils down to is your own perception of the vehicle. After driving it, are there some things you would improve upon in regards to acceleration or throttle response? Does it feel sluggish while taking off from a standstill? A performance chip alone would definitely help in these areas, but I'd be very wary and skeptical about a chip claiming to give you a huge amount of power without any other modification. However, if you're happy with how your car is performing and have no desire whatsoever to change it, I'd tell your co-workers to suck it. =)

I've driven cars that needed absolutely nothing done to it to improve on the driving experience. And well, I've also driven cars that practically needed to be torn down and rebuilt in my own image in order for me to be happy with driving the vehicle.

So, how does the car feel to you?

[deez nuts]

Originally Posted by 537

So, how does the car feel to you?

i like the feel of the car, personally out of all the cars i test drove when i was shopping around. handling wise on dry road conditions i.e. no ny snowstorm, it handles great. it's tight on corner turns. the braking is great. it did feel sluggish while going from a standstill compared to the other cars i looked at, but that's expected.

to be honest, i am curious about having the hp of the newer 35-40k cars out there like the G35 and others.

i think they were talking about a supercharger kit along with the chip.

do they mean something like this:

http://www.toyomoto.com/is300SuperchargerKit.htm

plus the addition of a turbo chip?

[537]

Originally Posted by Chasiubao_Boy

i like the feel of the car, personally out of all the cars i test drove when i was shopping around. handling wise on dry road conditions i.e. no ny snowstorm, it handles great. it's tight on corner turns. the braking is great. it did feel sluggish while going from a standstill compared to the other cars i looked at, but that's expected.

to be honest, i am curious about having the hp of the newer 35-40k cars out there like the G35 and others.

i think they were talking about a supercharger kit along with the chip.

do they mean something like this:

http://www.toyomoto.com/is300SuperchargerKit.htm

plus the addition of a turbo chip?

That sounds a lot more realistic to me. To see real world gains of upwards of 50hp, you'll either need to do extensive modifications to the valvetrain or engine block -- or choose forced induction. The supercharger you linked above does sound like a correct implementation of forced induction, seeing as how the modified fuel map is required to keep everything in good working condition. It's obvious they have done their research in putting together this kit, but if and when you become serious about something like this - make sure to request detailed dyno graphs complete with air/fuel measurements throughout the rpm band. Typically the details you will want to look at are the SAE corrected hp and tq numbers, and an air/fuel ratio in the range of ~13.7:1 (14.7:1 is all air, no fuel), ideally throughout the entire rpm range. You'll also want to ensure that the graphs are linear (as all supercharged applications should be...there should be no huge dip or spike in the graph except for a jump when an IS300 reaches VVT-i mode in the upper rpms).

But make no mistake! A supercharger + additional fuel delivery most likely will not give you an extra 185 horsepower. I definitely see it surpassing factory horsepower ratings of the vehicles you referenced (G35c, 350z, etc), but 400 horsepower is most likely not going to be realized with a supercharger.

[mrazntre]

CSB:

You've already hinted towards the main point that your co-workers speak of. They're talking mainly about acceleration or factory rated horsepower. Your car is definitely down on HP as compared to those other cars, but a car is not solely based on HP alone. The other types of things you have to consider are fit, finish and refinement.

Let's elaborate (off the top of my head):
350Z - not gonna fit many people in that backseat, interior is chintzy.
G35 coupe - not gonna fit many people in that backseat neither, interior is better, but chintzy still.
evo - the general consensus is that this car is ugly, interior is borderline.
wrx sti - paint sux, no radio, mad cabin noise.

You have other things to compare, rather than basing car value on horsepower. You have nameplate and resale. And as much as I don't like to mention, you have image, that is simply something that will not downplay if you're driving either an Evo or STi (btw: those aren't luxury nameplate cars).

There's a sacrifice to be made between horsepower and comfort IMO and the sales price or end product reflects that. I doubt that Infinity would completely refine the G35 interior and maintain its' price level. Historically, Infiniti's have had poor customer service. If you want luxury and performance, you need to step up to at least the $50K range (and from there, it skyrockets).


I agree with 537 that the supercharger and chip will not net you anything close to 400hp. If anything, a chip will only net you about 10hp or so with the addition of intake, header and exhaust.
You could probably get there with a turbocharger, reinforced block, new injectors, standalone ECU and exhaust system...but then you'd need a new clutch (oh wait, torque convertor), perhaps new axles and a stronger trans.

http://www.i-m-racing.com/ntnsracing/srtstagiiisu.html

I stand corrected, no new axles, but we're still 12 hp short.

[archspeed]

Intake, Header, Exhaust is good. But for a complete system, a High-Flow Catalytic Converter (Random Tech, Carsound) would be a great addition. If you decide to keep the old catalytic converter, you might get a lot of air in and out, but the stock cat will choke all the exhaust pulses up, and you don't want that.

You can run a test pipe, obviously, but there are many aftermarket quality catalytic converter out there that would flow as much cfm as a testpipe, but still be beneficial to the environment.

[537]

Originally Posted by archspeed

Intake, Header, Exhaust is good. But for a complete system, a High-Flow Catalytic Converter (Random Tech, Carsound) would be a great addition. If you decide to keep the old catalytic converter, you might get a lot of air in and out, but the stock cat will choke all the exhaust pulses up, and you don't want that.

Take special note that for Street-Legal vehicles, I advised that any replacement part you install on your car has a CARB EO number/license to remain streetable. A High-Flow Catalytic Converter, while appearing to remain on the right side of the law, is not a legal part to replace. In fact, Catalytic Converters fall under a special case, as it is unlawful to replace it unless it is no longer operating properly. For this reason alone, I will never advise a replacement catalytic converter for a vehicle that is driven on public roads.

The only mention I gave in regards to replacing this is on a race vehicle only that will not be driven on a public road.

Originally Posted by archspeed

You can run a test pipe, obviously, but there are many aftermarket quality catalytic converter out there that would flow as much cfm as a testpipe, but still be beneficial to the environment.

My apologies, but I have never seen any catalytic converter flow anywhere near the same cfm as a straight pipe. Where have you seen these magic cats? Where did they get these cfm benchmarks? Were these cfm readings gathered using regular air? Exhaust gas and atmospheric air are fundamentally composed of different elements with different weights and densities, so I wouldn't be halfway convinced in seeing a cfm comparison between the two unless they're using combusted air/fuel as its medium. Nevertheless, can you put up a link for me? You've got me curious!

Seeing as how replacing the catalytic converter is illegal except on race vehicles, I wouldn't replace an OEM cat, nor do I see any added value on choosing a "high-flow" catalytic converter over a straight pipe on a racecar. =)

[archspeed]

Ooops, wrong choice of wording. As a Honda guy, I have seen many cases where quality aftermarket cat converters will make more power in the IHCE system than a test pipe would, although the cat will probably not flow as much cfm as a test pipe.

The other fact is that a quality cat converter will pass smog just fine, visual and machine check. Sure, it is illegal to put on your car, but it is something that can be hidden away and pass with flying colors through all the test. So in my book, it's fine. The cops aren't going to tag you for an aftermarket converter. The only time you may get tagged is if you have an extremely anal smog check specialist, and that can be remedied quickly.

[Beat180]

I think I remember reading an article in Options about a year ago on the comparison of the HKS, Apexi, stock, all against the test pipe on the R34 as a test car. The test pipe flowed the most, with the apexi and hks basically neck and neck and the stocker way back. The apexi and the hks units though weren't far off from the flow rate of the test pipe and considering they're built for Japanese emissions, they've got the 3 way cats going which would be a concern for CA emissions vehicles. Just those cats are like what $600+?

[mrazntre]

Originally Posted by archspeed

Ooops, wrong choice of wording. As a Honda guy, I have seen many cases where quality aftermarket cat converters will make more power in the IHCE system than a test pipe would, although the cat will probably not flow as much cfm as a test pipe.

The other fact is that a quality cat converter will pass smog just fine, visual and machine check. Sure, it is illegal to put on your car, but it is something that can be hidden away and pass with flying colors through all the test. So in my book, it's fine. The cops aren't going to tag you for an aftermarket converter. The only time you may get tagged is if you have an extremely anal smog check specialist, and that can be remedied quickly.

Isn't it legal to replace "failing smog components" after 8 years?

[drydem]

What's your opinion on

1) Turbo (conversion) kits
2) NOX injectors
3) nitrogen filled tires