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Old 05-15-2000, 05:03 PM   #2
Catfish
Scooby Newbie
 
Member#: 1322
Join Date: Apr 2000
Location: Silicon Valley
Vehicle:
2000 2.5RS Sedan
72 Datsun 240Z

Post

In regards to your 3 reasons that N/A is not a good idea....

#1) As we all know, the current 2.5RS has a Phase II engine, which is SOHC. The cams are easily accessible from under the valve cover. I wouldn't define that as major work, but some people may. Of course, you have to remove the timing belt and some other miscellaneous stuff, but it's not that big a deal. I wouldn't go so far as to say it's more work than installing a Turbo, that's for sure.

#2) It depends on how "radical" your cams are. If you have a lot of overlap, certain vacuum signals are going to be out of range for the stock computer and errors will occur. However, a mild cam upgrade shouldn't post any problem, and I'm sure companies like Rallispec realize this and is the reason they have not released any cams as of yet.

#3) A cam doesn't change "valve internals" it merely alters the timing events as to when each valve opens and closes. By optimizing these values, you can optimize the power output of the engine. The Turbo just "force feeds" air into the system, thereby bypassing the valve timing. However, a camshaft that is ideal for a turbo is not ideal for N/A. The reason the 2.5L responds so well to turbocharging is because the stock cam is almost ideal for a turbocharger. This is great if you want to go turbo, but for N/A, it means the engine is GROSSLY undercammed.

I still believe, that with the proper mods, 200+hp can easily and reliably be produced by the Subaru 2.5L in N/A form.

Some Advantages to staying N/A route:

1) May not void your warranty. Just the installation of a TC voids it from what I can tell.

2) Much easier to pass smog checks if you don't have a big blowdrier taking up engine space.

3) Much cheaper to install, since you don't need all those aftermarket doo-dads to keep detonation in check. You don't need an Intercooler, piping, special computers, etc....

4) Easily removed if there is a problem, since most N/A mods are bolt on mods.


Dave
'00 2.5RS Sedan
'72 Datsun 240Z
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