Engine
There is alot of debate as to the effectiveness of this little device. It smoothes out the flat area between the throttle bores and decreases the air turbulence. (huh?!) Yeah, well, flow bench tests have measured 40cfm more air flow through the throttle body! As cheap and simple to install as these are, why not. Slight increases in power can be noticed (more if you've got ram air) but only at higher engine speeds when the air is moving through at high velocity.
This is an absolute must for a camaro. Nothing sounds like flowmaster. Your car will have a whole new image with a throaty rumble and an honest 10hp-15hp to the rear wheels. It is a fully bolt-on kit that will take about an hour to install (most of the time spent removing the stock one). They run you around $200-$300 and are well worth it. If you go with stainless steel, Borla makes a great system too.
Air filter upgrade mod varies from car to car. I have to tell you though, no matter what car you have, don't expect the gains that the company advertises. It's a good durable product and the extra money you pay is because it can be washed and re-used over and over again. The throttle response will improve slightly, but it is almost not noticable. An air filter is something you have to buy anyways so might as well get the best one so go ahead and get one! The LG Motorsports cold air intake for fourthgens are a different story. This is a must! You can definitely feel gains over the extremely restrictive OEM intake.
As delivered, most TPI engines have fuel pressures ranging from 35-47psi., depending on the model year. But stock pressure regulators are mass produced and it's common for actual fuel pressure to vary significantly from the factory specs. Installing an adjustable one not only provides the capability to establish specified pressures, it allows for experimentation at other settings. Before installing, install an in-line fuel pressure guage to see what the pressure is in the stock condition. At first glance, it would seem that raising the pressure would serve no purpose because the ECM will simply sense a richer mixture and alter injector pulse width to compensate. Although that is precisely the action taken, higher pressure is advantageous because the fuel atomizes better. Knowledgeable engine builders install downsized injector nozzles specifically so higher pressures can be run without causing exessively rich conditions. As long as the pressure stays below 55psi. (for a stock computer) then the ECM will have no problem making the proper adjustments to compensate. The bottom line, if you are redoing the whole induction (manifold, TB, runners, plenum) or anything major, it is worthwhile to install one. It will give you more flexibility in how you want to run your engine.
A good set of headers will really wake your engine up. In addition to a more throaty exhaust rumble you can expect noticable increases of 15hp+. If you want top quality go with a stainless steel set. Nickel coated will give you a nice chrome finish, but it will turn sorta blu-ish after a while. If you don't get stainless steel, don't really worry about it, they will last for years without a problem. Coating them with a high temperature spray like VHT will not last unless you bake them properly, even then, results aren't as good as expected. I definitely recommend sending them off to Jet Hot to be professionally coated before installing, this is the best route, they will look great and last long. They are a pain to install and you can expect to spend a full day on the project. Your knuckles will be bloody but it's well worth it. I recommend spending the extra money on a good quality set like Edelbrocks, SLP, or JBA, they will bolt on with less trouble than cheap sets.
The results from this varies from car to car. For imports, I have heard nothing but good things, but when I put one of these into my 91 camaro, I realized that "hyp" is short for hypertech. It will give you best gains if you have upgrades like exhaust or higher flowing intake, but not too noticable. Acceleration is slightly smoother and shift points are optimized on automatic transmissions, and best of all, no more speed limiter IF you get the right one. Make sure you mention that before ordering it because you could get stuck with a speed limited one. One bad thing is that you have to use super unleaded gas, but thats what you should be using anyways! Overall, if you have the money, sure grab one, but if not it is not a necessity.
You get the gains from the chip, but more importantly, if you are making modifications to your car such as rearend gears, or tire size changes, this is a must. They run around $300+ but its the only way you can recalibrate your speedometer. It is super easy to use and you can adjust shift points, tire size, gear ratio, speed limiter, and power tuning. If you are buying this just for the special hypertech tuning, it's a waste.
The MSD 6AL is a multiple spark discharge unit. It provides a powerful spark for 20 degrees of crankshaft rotation. So maximum spark energy is put into one lng fat spark when an engine is operating at speeds above approximately 2000 rpm. They come with a special harness that makes installation extremely simple. Toghether with some thicker wires (7-8mm), throttle response improves slightly and fuel economy improvement is noticeable. If a coil is used, larger plug gaps can be utilized for even better efficiency.
You get one of these little things when you buy a Hypertech. Personally, I think the chip is wrongly credited to the increased power, its really the thermostat! Your car will run super-cool and you will have full power on tap at all times. It will keep your engine running at a magic temperature range. This is under $10 bucks at kragens or grand auto and it is the most cost effective bolt-on you can ever buy. Installing a electric fan toggle switch is a great idea that will further enhance the cool-running engine experience. No matter what anyone tells you, a hot engine is inefficient and loses power.
Standard Chevy rockers have a theoretical 1.5:1 ratio, but realistically, few meet this specification, so actual valve lift is less than the theoretical specification. A relatively easy way to increase performance is to install 1.6:1 rockers to increase lift. Results can be impressive (10-15hp) when mated to a stock cam. Increases are usually less dramatic with high performance cams because lift and valve opening have already been increased so in most cases the valve is already outflowing the port, so lifting it higher doesn't do much. 1987 and later blocks use roller camshafts so roller rockers will be necessary.
It seems obvious that a larger TB increases airflow capacity and thus horsepower. But if there is restriction somewhere else in the induction system, a TB with a larger bore will have little positive effect. With mods like larger runners and manifold, ported plenum, headers, and manifold heads, then a larger TB will increase performance by supplying the extra airflow. There is a wide selection of aftermarket TB's, bore sizes ranging from 52-58mm with flow capacities from 600-1000cfm.
Larger runners naturally go hand-in-hand with a higher capacity intake manifold; it's best to purchase and install both at the same time. The same brands as mentioned above make the best product, and most are emissions-legal. These can get pricey, but if you have the funds, get one.
This is often overlooked but it is an important link in the horsepower chain. The plenum is basically a storage area for air, but it also affects airflow potential. the Lingenfelter Super Ram is the best in the market but it is expensive and should be considered only for a high-budget build-up. A good idea for mild build-ups is just to port the stock plenum, removing sharp edges and blending the connection to the runners.
High performance runners are larger in diameter and consequently have higher airflow potential. This translates to increased torque and horsepower, and they raise the torque peaks 250 to 500 rpm. Along with that comes a slight decrease in power below 2000 rpm. Installation of aftermarket runners is most effective if the engine has already been equipped with low-restriction exhaust. Be forwarned, aftermarket runners can actually hurt performance if they are not port-matched to the plenum and manifold, so pick a quality product like Arizona Speed and Marine, TPI Specialties, Edelbrock, or Lingenfelter. If buying a plenum, runners, and manifold, keep the brand name the same.
Pulleys can dress up the engine and provide a noticeable rear wheel power increase. March seems to be the favored brand. If your alternator or water pump are in bad shape, then I wouldn't suggest pulleys because pulleys slow down your charging and cooling abilities by slowing the rpm of these accesories. I would also avoid pulleys if you have a high powered stereo. The lower turning RPM of the alternator will not be sufficient to charge the battery properly (especially at night when all the lights are on).