Dixie_Flatline

MOD NOTE: I'm going to sticky this. But please keep this for informational posts only. Let's keep specific product questions and recommendations out of it. I'd like this to be for learning purposes about the technology and ideas behind it - not "should i get this intake or header?" - THANKS!

***DISCLAIMER*** Anyone familiar with the workings of a car can probably turn around now. This is meant simply to give my opinion on how to approach tuning for a novice. If this has been posted before and I didn't see it let me know and shame on me. Now back to our regularly scheduled programming:


Ok kids, I want to post this up as I see some of the same things pop up over and over (and over and...). Hopefully some of the regulars can throw in their 2 cents as well (and correct any oversights/mistakes I inadvertantly make).

So you want to make your car go faster? Ok, but before you start buying parts left and right, let's take a look at some of the basics. You need a plan. Increasing the performance of your car is (should) be a very involved intellectual pursuit. You need to know HOW your car operates before you can make it operate better. So the first question:

What do you want the end result to be? If you want your car to run a little hotter than stock, but you're hurting for cash (or time), maybe you should just consider the basics. I hate to use the term, but I/H/E. If you increase the efficiency of the process by which air goes into your engine and the exhaust gases leave your engine, yes, you will see some gains on the dyno. Amazingly enough, these mods are all simple enough that most anyone can perform them, provided they have A) The proper tools and B) Patience.

A little shout-out to the people who ask what the "best" exhaust/header/etc is - this really does come down to personal preference. You might be a power-hungry guy who doesn't care what the exhaust costs, sounds, or looks like as long as it performs. But maybe you live in the real world. Maybe you'd like a nice, throaty rumble, and are willing to concede some horsepower gains at this stage for a civilized I/H/E setup.

Remember what I said before - the trick is to always remember the end product. If you aren't satisfied with a few extra horses under the hood, you might need to pop the I out of that last equation. That's right, Superchargers and Turbochargers are both forms of Forced INDUCTION (read: intake). So that super-duper Weapon R CAI you bought to add 4-8 hp is now worth essentially bupkiss. Super & Turbo chargers force compressed air into your engine. This is much better than just sucking in whatever cold air happens to be around. If you'll recall, Air + Fuel + Spark = Vroom. By the Eleventyth Law of Thermodynamics then, Forced_Air + Fuel + Spark = VROOM. As you can see, the vroom is bigger (we can discuss the NOS Theory in a later class).

FI brings on a whole other side of power gains though. The enormous boost you realize from these systems also require equally enormous investments of the previously-mentioned time and money. Turbos will almost always need an intercooler to keep everything frosty, and a blow-off valve for the "pssssh" sound the kids all love these days. You also need to start thinking about the internals of your engine - the seals, gaskets, rods, cams - all those little parts that were designed to keep our tCs under $20k, not under 13.00 on the 1/4 mile. And it doesn't stop with the engine itself. Your clutch/flywheel combination needs to be able to control those gears, and your brakes need to be beefy enough to stop you.

I haven't even gotten into adjusting the suspension of the rather portly tC, which you WILL need to control all this power. Nor have I touched on the hardest part - fuel mapping/tuning - more air in your motor means it needs more fuel. But you get the picture. If you want to give yourself that feeling of "wheeeee!" when you drive your car, think it through. Example, don't just buy the header that will give you the most horsepower. Look at it from a Big Picture perspective. A header by itself might give you some gains up high, but what if you add an exhaust after your next paycheck and it cuts off some of your down-low power? Maybe you want a 4-2-1 instead of a 4-1. Ask for advice, there are plenty of knowledgable people floating around here. Maybe you can save yourself some of that precious time and money.

That being said, don't let me spoil your dreams. I wish just like the rest of you, for an unlimited budget, personal mechanic, and time off work to spend with my car. I'm just trying to help out some of the so-called n00bs who don't know anything beyond gas pedal = vroom and don't know where to start. Later.

-Matt

Nebraska_tC

thanks matt very insightful you should add a little about suspension some time for some people that dont know the fun of having a car thant turns like its on rails

Dixie_Flatline

I would, but this is "Power Hungry", so I tried to keep it as on-topic as I could. I could write Suspension 101 and explain the differences between a comfy ride and a fun ride, the temtaption of lowering for looks rather than corners, etc, but this post is long enough by itself, I think. If the people want it, I'm sure it will happen though.

400amonth

Also consider that just adding I/H/E can itself lead to more money. So I had the TRD exhaust for mild performance and great sound. Then the K&N intake for a bit more sound/power. Then the AW header and boom it got too noisy for my taste. So you get the S-pipe ..gotta go stainless $175 more to reduce rasp...still does not do it. $200 more dollars on custom dual magnaflow mid pipe work with big ole resonators. Next thing I know I have spent near $1400 on a I/H/E that I can live with on sound that did dyno 160 at the ground.
Now the next guy could go Ebay intake/cheaper DC header/aluminum S-pipe and the cheapest S-pipe back system he can locate and dyno 157.8 ...may sound like a bumble bee but still LOVE it for only $700-800 invested.
Last scenerio the guy who wants the bling true import tuner. He has to have a $600 S-pipe back by a popular sport compact car name brand exhaust..he even drops for the Monster Motorworks header and S-pipe for another $800 and then drops for the ARC intake box for another $500 and he dynos 161.2 for $1900 and may still sound like a bumble bee cause those sweet S-pipe backs still lack lots of resonators.

Alot of it comes down to taste and budget. I also do agree that that when you when you go further than this it still can be addictive and can you keep up? So you get the SC for $3500 installed. Ya know you could intercool the charge and get more power? Well theres another $500 and ya got to take it off before those warranty visits you was shooting for with a factory SC. Wait a second..some one just e-managed a SC kit and got 30 more HP for only $1000 more! Then a pulley kit comes out for $200. Now you got to un-install a ton of stuff for those dealer visits on that factory super charger. I wont even go into the turbo stuff can it can get just as in depth. All this stuff you are hearing about has lest than 10,000 miles on the cars running it. So what anyone says about long term is truely not a for sure but its the risk you take. I think Toyota feels the car can handle another 40 or so and be safe with a re-flash of the ECU.

Last thing is it seems more real in steps..a little here and a little there. If you can pull off saving money for a longer period you just may be able to trade your car sooner than you think for a better platform or maybe a bike so you can really feel what fast is about.

Just my 2 cents and I am as guilty as anyone on blowing cash.

Scott

ignitionr34

both of u guys nice write ups!! i think this should be a sticky for the "general tc section" called NEWBS READ THIS BEFORE DOING NY THING..HELPFULL TIPS"

ack154

iTrader: (7)

This part killed me:
But ya... good job guys. Very basic, yet gets the point across. If we can have a couple more contributions (even something more in depth?), I'd consider this a sticky here in PH (wouldn't go into General tC though).

WingspanTT

I am a total noob, can someone put info on what are the best things to do first for both value/performance and sound? If you're short on cash, is it better to do intake first, or exhaust?

jmiller20874

I'd say if you're short on cash, the intake would be first but then again you can get a decent header for around the same amount. If you go the header route, you might notice a little rasp with the stock exhaust in the upper RPM range. If you go the intake route, expect a nice growl when you get on it but you could lose a little low-end torque.

Header Pro's & Con's
---------------------
More bang for the buck than an intake (PRO)
Looks great (PRO)
Longer/harder install (CON)
Could produce upper-RPM rasp (CON)

Intake Pro's & Con's
---------------------
Easy install (PRO)
Looks great (PRO)
Sounds great (PRO)
Could lose some low-end torque (CON)
Less gains than the header (CON)

Both products are not CARB legal.

Dixie_Flatline

Ok, let's look a little further into some of these parts. I'll start with the header. The aim of the header is to replace the stock exhaust manifold. In the stock setup, all four cylinders of the engine release their exhaust gases into the same manifold. The idea is to eliminate back pressure. Without going into too much detail about the 4 stroke cycles of the engine, back pressure is the problem that arises because all 4 cylinders are trying to funnel their exhaust through the same hole. A header (4-1, get it?) gives each cylinder it's own channel, all of exactly equal length (which is why the pipes are bent so precisely). This prevents any one cylinder from backing up the exhaust route to the cat. If one cylinder's gases get backed up in a stock situation, the next cylinder has to push harder to get its gases out. This reduces the amount of power available for the rest of the car (ie, your wheels). That's back pressure.

So by slapping your nifty header on there, you eliminate the back pressure. Swell, right? The problem is it makes the whole set up louder, as noted above. Especially in the higher RPM ranges. The simple fact is that the stock system isn't designed with performance in mind. It is a combination of factors - performance, sound, reliability, cost. The majority of new-car buys don't want the bumble-bee sound, so to eliminate that noise there are a number of tricks that they use, like resonators and sound-dampening materials. Those, in turn, reduce the power efficiency.

So, as was stated above, stop and think. You may be able to convince yourself that the cheapest header is the best idea. After all, performance gains might not be that different between different headers, but a lot of us sure notice a $150 or $200 difference in price tags. But is that dollar difference worth the aggravation of possibly sounding like a dirtbike going down the street? Only you can say.

Next up: Why is cold air better? (The simple facts behind CAI, CAB, and intercooler setups. Bonus if anyone else knows how NOS affects air temp!)

*EDIT* While I'm thinking about, a quick note on the Check Engine Light (CEL) that everyone is terrified of angering. What do we mean when we say the mixture is lean/rich? Quick physics lesson: The stoichiometric point is the "ideal" ratio of oxygen to fuel. At this point, all of the fuel will burn all of the oxygen, leaving only the various hydrocarbons, carbon monoxide, and NOx (nitrogen oxides). If there is more oxygen, the mixture is lean. If there is more fuel than air to burn it, the mixture is rich. Neither condition is particularly good, as they represent an inefficiency somewhere. However, running lean (too much air) is worse, as you risk engine detonation as you get leaner, which is about as bad as it sounds. Modern cars are generally designed to run a little lean - the unburned oxygen in the exhaust is used to burn off some of the pollutants in the catalytic converter.

The O/2 sensor (I think I read that it's a MAF on the tC, but I haven't had the pleasure of confirming this yet) checks the exhaust and reports back to the ECU, which then adjusts the electronic fuel injection (efi) system to be closer to the stoichiometric point accordingly. When you throw a CAI on your car, for example, it confuses the hell out of the ECU. *BAM*, CEL comes on. How is it supposed to know the difference between a leak in your engine and a CAI? We'll get into why cold air is different later. These "anti-foulers" you see are just workarounds that mask the reading the O/2 sensor takes. Thus, it doesn't fix the problem, it just fools your ECU into thinking everything is normal.

ignitionr34

LO BUX RACER... this is where u come in!!!

emiller

Good advise guys. Think about what you want your end product to be and how much you want to spend. Everybody has different goals so not everyone will agree one what the best part is. Pick the ones that fit into what you want.

Dixie_Flatline

Alright, if you haven't noticed, I'm home sick from work today, so I've been patrolling the SL forums like a pedophile at a playground

Ok, so as for my previous question, how does cold air affect an engine, and what does this have to do with NOS? Well, the answer is again simple physics. Colder air is much more dense that hot air (this is the principle behind hot-air balloons). Thus, you can get much more oxygen into the same amount of space. Another added benefit of a Cold Air Intake (CAI) is the less restricted airflow. A typical stock air filter is designed to filter out the maximum amout of dust and debris. This keeps the engine clean but also restricts the flow of air into the engine. The exact same principle (cold air, not air flow) is what makes intercoolers necessary in any serious turbo implementation - the compressed air leaves the turbine (quite warm) and takes a little trip through the intercooler's frosty pipes.

Upsides to intake mods include the (smallish) boost in efficiency and small change in noise. Compared to changing the exhaust path, the intake path has a much smaller impact on noise levels. It's also one of the easiest installs you're likely to encounter; although it is generally not 50-states "legal", if you need to take it off for any reason, not a problem.

As for the bonus question, Nitrous Oxide (NOS is actually a trademarked brand-name version) creates its boost by adding more air (oxygen) to the equation. You see, when Nitrous Oxide is heated in the cylinder, it separates into separate Nitrogen and Oxygen components. The Oxygen is our burns-into-energy friend, but what you might not know is that the Nitrogen actually induces an endothermic reaction as it vaporizes - it absorbs heat. I don't think I need to mention again how this helps air density or increases power, right?

Anyone have any preference about what they'd like to hear about next?

400amonth

i have thought about nos but i hear our plastic intake manifolds will crack.

jmiller20874

ZPI is the only one who has blown an intake manifold and that was with a 125-shot. Much more than you'd need to do, a 50-shot should be plenty safe.

ScionDad

Well, a CAI should not throw a check engine light. It is the header that throws this light. The ECU will read the change for the CAI via the MAF and once the new flow is learned, it will be fine. Just let the car idle for a few minutes and drive moderate for a few miles, you should be fine. You don't need a mod to trick the ECU out of this condition on the TC.

The CEL does throw with a header. It is the 2nd sensor that throws this code and that is due to the first cat being removed from the equasion (there is a cat in the stock manifold plumbing).

miraclecreator

very interesting, I have a TRD exhaust, looking for a header now, any suggestions?

Dixie_Flatline

Apologies, I should have been a little more clear. The reason the CEL _stays_ on is a header. It may come on for a little while after installing a CAI, but disconnecting the negative terminal of the battery for a minute and the letting the car idle for a little while should be enough to calm down the ECU. As was stated, you actually lose a cat (pre-cat?) when you trash the stock exhaust manifold. A cat, for those of you who don't know, is a catalytic converter. It uses various methods to eliminate pollutants from your exhaust, the above-mentioned NOx, Hydrocarbons, and CO (Carbon Monoxide). When you remove the cat in the factory manifold, it doesn't just confuse the ECU, it scares it ____eless. Suddenly you don't just have extra O2 in the exhaust, you've got all sorts of lovelies in there. This is also one of the reasons headers add the 'rasp'/noise - cats tend to slow down and quiet the exhaust passing through them.

ScionDad

All in all...a very nice addition to the forum. Should help reduce a gazillion extra posts

ack154

iTrader: (7)

We're going to try to keep this thread for information purposes only. If you're looking for recommendations, I'd suggest searching first to find out what others have and like. And only after you've searched, create a new thread if you don't find anything relevant.
Heh... in theory. Ya.

ack154

iTrader: (7)

Stickied with a note in the first post. ALL PLEASE READ IT.