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Stage 3 | head parts

Difficulty | 3

This is where we talk about those components you purchase to install in the head aside from machine work. Some parts you would be smart to upgrade, almost considered requirements by some people, but most are totally your choice - remember your goals!

Cost | $400+
It's been so long since we've heard of someone using regrind cams, that we'll stick with new, billet cams. The two big names to remember in the 2GNT community are Crower and Crane. Both are well-known to car guys everywhere and offer quality products. Which brand to pick is a matter of personal preference.

Mild | (Crower_1 or Crane_0010, Crane_0012) Don't necessarily require upgraded springs or lash adjusters. Most people who install these say they wish they had gone with the next step up.

Medium | (Crower_2 or Crane_0016) Require upgraded springs and lash adjusters. You don't want a valve floating (staying open) or falling into the engine, do you? These will require some tweaking to run on cars with stock fuel systems, but are not too aggressive.

Turbo | (Crower_2_Turbo or Crane_0014) If you're building the head for a turbocharged application, opt for these models to help spool your turbo faster.

Hot | (Crower_3 or Crane_0018 and up) Very few of these cams being used in daily driven 2GNTs. Low end power is traded for all out race performance. Some Neon drivers (they're crazy) actually run as high as Crane 0024s! You will HAVE to have the ability to tune your fuel system if you want your car to idle with these. Not advised for the street.

Adjustable Cam_Gears
Cost | $150
Power | more gains when used with upgraded cams
Difficulty | 3
Cam gears allow you to advance/retard the timing of your intake and exhaust valves in the interest of making more power (by getting more air/fuel into the combustion chamber). Will require dyno tuning to see best results and can result in a nasty idle like an old muscle car.

Cost | $150 and up
Power | negligible, at most
You can use a set of new stock springs to freshen the head with a mild cam or upgrade to performance springs with a more aggressively ground bumpstick. These upgraded springs are what force the valves to close once the cam lobe has peaked. You don't want a sloppy valve train.

Cost | $200 and up
Power | negligible, at most
Also known as lifters, these are hydraulic bits that apply pressure to the rocker arms to keep things tight and slop free. Most people upgrade to the lifters from a PT Cruiser's 2.4L engine.

Rocker_Arms (See also: Roller Arms)
Cost | $250 and up
Power | negligible, at most
Picture this as a little teeter-totter upside-down under your cams. These roll along on the camshaft and the cam lobes press down directly on them. They transfer this motion to the valves and open them. A lot of people also source these from the PT Cruiser 2.4L as an upgrade. You don't want one of these to fail on you.

Cost | $150 and up
Power | negligible, at most
You can get new stockers for peace of mind or step up to Titanium from a manufacturer such as Crower. Titanium is lighter and stronger than steel, so getting Ti retainers can appeal in terms of durability, but the biggest benefit to getting Ti retainers is the weight reduction. No, this does not lighten the weight of the car enough to be useful, but it reduces the amount of weight resting on the valve spring which makes for a freer moving valvetrain. The cams will still move the valves like they are supposed to, but the springs will have less weight to push back up upon closing of the valve. They are pricey, but worthwhile if you're going all out on your head.

Cost | $200 and up
Power | gains are proportionate to level of build
2GNT experts agree that the stock intake manifold is a turd, but there is yet to be an aftermarket sheet metal intake manifold that is any better. Your best bet for value is to have the injector humps machined out of the lower half of the manifold and have the runners ported to match the gasket and intake ports on the head. The top half can have the throttle body (TB) port opened up to around 56mm before you risk making the walls of the neck too thin. Material can be welded there to allow porting to 60mm or more, but this is not done very often. The extreme end of manifold modification would be to have the above mods done and then get it all Extrude Honed. This is cost prohibitive for most people. Being relatively easy to remove (compared to the head itself), you might save this for later if you really want to do it.

Throttle Body (TB)
Cost | $75 and up
Power | gains are proportionate to level of build, throttle response is improved
The stock TB can be bored up to 56mm before the walls get too thin. The other alternative is to buy a premade 60mm TB from a vendor like Modern Performance or modify a Jeep TB (from the 4.0L inline 6 cylinder engine) to fit. Turbocharged engines can really see nice gains from larger TBs, while NA applications might become a bit twitchy (throttle response) with anything larger than 57mm.

Exhaust System | Cat-Back
Cost | $200 and up
Power | greater gains will be had from built/tuned engines
Difficulty | 3 - 4
You've already installed your header, so now it's time to focus on the rest of the exhaust system. While a used GST catback exhaust will suffice for most NA tuners, a mandrel-bent 2.5" (inner diameter - I.D.) exhaust system is better with a fully built engine that flows a lot of air. You can make this yourself with pieces bought online or buy a premade system if you prefer.

Exhaust System | Catalytic_Converter/Test_Pipe
Cost | $20 to $200
Power | decent (at the cost of legality and sound quality)
Difficulty | 2 - 3
The catalytic converter, or "cat," is a federally mandated piece of the exhaust system which exhaust shops are not allowed to remove from a vehicle unless it is found to be defective. Options include replacing the cat with a "test pipe" that is nothing more than a piece of pipe that bolts into the exhaust system in place of the cat, hollowing-out a stock cat, or replacing the cat with a high-flow cat. Be careful when shopping for a high-flow cat. Most of the ones you see online are nothing more than a resonator (sound dampening device) that does nothing in terms of preventing pollution. Worth noting is that test pipes, hollowed-out cats, and resonators will result in a much raspier exhaust note which you might find annoying.

Cost | $300 and up
Don't forget the "little" things like an upper gasket_kit, which will have your intake and exhaust manifold gaskets, cam seals, TB gasket, spark plug tube seals and valve cover (VC) gasket. You can also opt to install ARP cam retainer studs to reduce the risk of stripping out the aluminum threads the stock bolts use. You will also need some form of assembly lube, RTV, and anaerobic sealant to put the head back together all the way.


Document statistics: Last modified on 2006-08-08 10:05:38 by DR1665

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