Nat Aspirated Power Gains

[chrisearl88]

A cold air induction and a smaller rear muffler might net 5kw if your lucky, but the sound will make you feel like your going way faster.
Ive done the cold air, extractors,cat, full exhaust and the only thing that made a noticeable difference on the butt dyno was the extractors.

In terms of bang for buck going to an lsd with a higher ratio is a good bet as long as you dont do a heap of highway driving, and you will need to be prepared to calibrate the speedo.

Honestly the best mod i did was king lowered springs plus koni adjustable shocks, completely transformed the handling, especially if your car has a few km and is still running original shocks. Oh and get a wheel alignment!

[speed freak]

You could add CAI and exhaust for sound if you like but just use good oil and drive the nuts off it. They aren't turbo quick no but they aren't slow use the higher rpm range plus these aren't about straight line speed and power anyway. Like others have said get swaybars and coilovers or a good shock/spring combo, lightweight wheels and sticky tyres with a good wheel alignment. They also handle great from factory but there is always room for improvement and I would guarantee these handling mods would be much more beneficial and a lot more fun especially on the street instead of adding a few more kw with basic bolt-ons. Adding more power is different if your committed to doing it right the first time and have all the supporting mods and quality parts etc these add up quickly and if not done right could cost you an engine. If you plan on selling it doesn't seem worth it spending money on engine mods.

Its funny how many speed past me on the street then the come to a corner and have to slow right down but me? No just downshift and accelerate and you end up way ahead of the speeder. In other words power isn't everything on street or track.

[Mr Morlock]

based on "My uncle has a massive mechanics garage I can play with on occasion, and he's more than happy to guide me through things.
I'm only part time, so I'm bored and have too much time on my hands.
I'm not paying rent, loans, credit cards or whatever.I figure these are the last two years I can blow all my money on my car, alcohol, cigars and steak without causing myself financial problems, so..."

I reckon you can do something far more useful like make some contributions to other peoples support rather than waste it on a car- ie money- a thing that should be respected.

[rascal]

What kind of gains would an exhaust, camshaft, cam gear and ECU yield? Are these worthwhile on their own or are they simply a prerequisite for ITB's?

I have exactly this on my NB8A (plus intake) and end result was 101rwkw.. (up from 72rwkw when stock) so 40% improvement.
Definitely worthwhile, though would use up most of your $4000...

[Magpie]

Doing NA is a holistic thing, it needs to be planned and well thought out. Non off the shelf ITB'S have been done by others and as suggested a Megasquirt will also keep the costs down.

My thoughts are do a lot of planning and research, in the mean time give the car a good wheel alignment, diet and have some drive quick lessons. Questions to think about are where do I want to make the power, what do you want it rev to, how long between rebuilds. The higher spec engine gets its life measured in hours no distance. Do you want to manage the oil pressure externally, do you want to put some fail safes in to protect the engine like an oil accumulator or master warning light/piezo for oil/water/oil pressure. Do you want to run 2 injectors per ITB'S (one low for starting, one high for high RPM)?

Also think about other parts of the car, brakes, suspension, aero etc. it is a whole package and needs to be well thought out. I can PM you some details on my NA build, however I have no idea as to what the final HP will be because the specs for the build was max torque around 5250 rpm then flat line to redline. So cam/lift decisions were made around what the planned outcome.

Good luck and I hope you enjoy planning the build as much as I have mine. I now can't wait for it to be finished after over 12 months of planning.

[gslender]

Why the injectors top and bottom. Whats driving the need for this?

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[davekmoore]

Erm, I know I keep saying this, but how about just adding a decent rollbar and spending your $$$$ on track days?

Later progress to having a CAMS licence, club membership (PM me for details of Mazda Car Club of Australia), fire extinguisher, tow hooks etc so you can do some sprints?

Then, after two years, maybe consider going turbo. If you can buy a complete turbo car that's already sorted you will save yourself a lot of pain.

[Apu]

If you want to go fast on a budget without going FI, then my question to you is:

"What is the trade off you are prepared to live with?"

If you think your next car is going to be an Elise or Exige, then my suggestion to you is strip the daylights out of your car, make it as light as possible. Then use what money you have left from that $4K to pay for the track days where you will learn how to drive fast.

[Magpie]

Why the injectors top and bottom. Whats driving the need for this?

http://www.jenvey.co.uk/jenvey/throttle-body-selection-with-jenvey-dynamics

Where is the best place for the injectors?
Where one injector is to be used per cylinder the best compromise position is immediately downstream of the butterfly. This gains maximum advantage from local turbulence and gives results surprisingly close to the optimum at both ends of the rev-range. This is the recommended position for most applications.
For performance at low RPM, economy and emissions the injector needs to be close to the valve and firing at the back of the valve head. This is the favoured position for production vehicles.
For higher RPM (very approximately 8,000+) the injector needs to be near the intake end of the induction tract to give adequate mixing time and opportunity. The higher the RPM, the further upstream the injector needs to be. As a result, use of speeds above approximately 11,000 RPM may give best results with the injector mounted outside the inlet tract altogether (see our remote injector mounting). It is common to fit both lower and upper injectors in such a system to cover starting and low RPM, as well as high speeds.