NA tuning - engine modifications

Now that we've changed complete exhaust and intake system and we still don't have enough power, now it's engine's inside turn.
Increasing compression - change pistons with high-compression ones or replace oem head gasket with a thiner one.
Cams - OEM cams don't have the optimum aggression. They are classified by stages of aggression: stage 1, stage 2... Be sure you choose the right ones for your goals. Some of them are better for mid-end range, some of them give more power, some more torque...
ECU optimization- it's necessary for tuned cars. Cam timing, ignition, how much fuel goes to the engine, if there's too less fuel going in, power of car won't be optimized and you can hurt your engine for that. If power is too big for OEM injectors and fuel pump, replacing them with bigger ones is a must. ECU tuning should only be done by professional tuner on a dyno. If you don't know how to do it, don't try to do it yourself, you can make more damage than good stuff.
Valves + valve springs: Put in some sport aftermarket valves and springs, especially when you increase redline of rpms on ECU tuning. OEM valve springs probably won't last long when rpm redline is changed to 1000revs higher than stock and a big damage can be done to an engine.
Engine head - Port polish a cylinder head increases compression, it optimizes power and turns production engine into a racing one.
That's about it for NA tuning, don't forget to optimize transmission: lighter sport flywheel, stronger clutch and LSD in your gearbox for optimized performance.
Don't forget: This are just some basics to imagine how things go in tuning, don't tune if you aren't sure how things work and what will your modification exactly does to your car;)

Header difference in performance 4-1 or 4-2-1

It's a performance difference between headers. (4-cylinder engine) Basically...
Numbers (4-1, 4-2-1) means how pipes join together; 4 directly in 1, or 4 to 2 to 1.
4-1 pipe header brings more power in high revs, that gives better acceleration on a straight line and bigger max power, but you will have to push up your car on high revs all the time to notice a difference.
4-2-1 pipe header brings more power through all the revs area, more practical for everyday use, gives more torque and power in low to mid rev area.
Which one would you choose? It won't bring much power on a complete stock car, for noticeable difference get sport cat-back for a start and start tuning your monster :)

Mugen 4-1 header for Honda B-series engine


Skunk2 4-2-1 header for Honda B-series engine

pic source: jhpusa.com

NA tuning - Basics

Tuning is adjusting, modding and replacing components of car to improve it's handling and performance.
Tuning should be done only on healthy engine, unless your budget is too big... first take care of engine's "health", or it will only get worse with further tuning.
NA literally means Naturally Aspirated, pressure of air going to the engine is atmospheric, that means no turbo or compressor.
Where to start NA tuning?
-Cat-back - Improving complete sport exhaust system so the engine can "breathe" is somehow a basic for further tuning of a car. Fi of exhaust pipe should be bigger than stock because we want to increase power and more power means more air going through the exhaust.
-Header - right choice of header is more crucial than cat-back itself. You choose between 4-2-1 and 4-1 header (4 cylinder engines)
- de-cat pipe - It's an empty pipe to replace catalyst, which combines together cat-back and header. There are some loses in catalyst due to cleaning filters inside, de-cat pipe saves it. Alternative solution of de-cat pipe for Greenpeace members is sports catalyst. But if you are a Greenpeace member, you probably drive around in a bike, so no tuning needed for you:)
(Toda exhaust system)

- Air intake system - You can change air filter in airbox for some more breathable sport filter, bigger airbox, SRI or CAI intake. SRI (short ram intake) is mounted directly on throttlebody, it only speeds up reaction of engine, doesn't increase power, that's why I recommend CAI (cold air intake).
(AEM CAI)

It's a pipe with air filter on the end of it from throttlebody to a front bumper usually, it intakes cold air, which gives more power to the engine, than warm air under the hood from SRI.
Than u change OEM intake manifold and Throttlebody for bigger sport ones, so more air can come to the engine, it gives more power and torque.
(Skunk2 intake manifold)

(Blox Throttlebody)

That's it for a start of NA tuning, next level is direct intervention of engine, cams, valves, pistons, ECU re-programing, valve springs... we'll get to there soon ;)
Don't forget, more power means bigger speed. Don't just tune your engine and maximize your power output, be sure you are safe, don't forget to upgrade your brakes.
Not enough? Check out some basics of NA modifications directly on engine.

Definition of Touge Battle Ghost battle, Sudden death, Straight up

Touge means pass, in JDM scene it refers to races on the mountain roads or any of the narrow, roads that can be found in Japan and other geographical similar areas.
We know 3 types of touge battles;
Sudden death - cat and mouse race
It's used when he road isn't wide enough to pass the opponent. Two cars start the race one behind another and a car in front must increase the gap between them to win a race. The second car must keep the gap or decrease it until the finish line to win the touge battle. If the first car gets passed, it automatically looses the race. Than they change positions and they race again...
Straight up
When the road is wide enough for cars to pass each other, they start the race in the same line and the first one through the finish line is the winner.
Ghost battle - Time attack
Cars don't drive together at the same time, they drive separately and they are timed from start to finish line and the one with better time is the winner.