Underdrive Pulleys And Cam Gears

[Goldenboy]

You should try to decide if you want to go NA or FI. That way you don't buy anything you'd end up selling in the near future.

[imported_knowles101]

if I where to start with forced induction would a supercharger be a better option than a turbo?

If I do go FI I would obviously have to redo all the internals right?

[Calesta]

No, you don't have to build up the internals for boost. You can easily make 250whp or more safely on stock internals.

If you're going to spend money upgrading the engine now, dropping cash on pullies and a lightweight flywheel won't get you near the performance increase as other true power adders for the amount of money you spend. An aluminum flywheel is about $300-350. Pullies cost about $100-200, and don't help you more than 2-3hp at most (at the crank too)- and can destroy your accessories or ruin your engine if you replace the harmoic dampener on the crankshaft. Go buy more useful items like cams or an intake manifold. Replace your flywheel the next time you change your clutch. It's more convenient that way.

[Smooth_Imports]

Originally posted by knowles101@Jul 18 2003, 06:40 AM
if I where to start with forced induction would a supercharger be a better option than a turbo?

If I do go FI I would obviously have to redo all the internals right?

As mike said no you don't have to upgrade the internals right away just make sure you get a good tuning job done.

As for going with SC or turbo. This is a matter of opion.


SC= Pro, you get power right from the start there is no lag.
SC= Con, It's belt driven, It takes power to make power, You have to replace the pulley to up the boost


Turbo=Pro. You can up the boost with a touch of a button, It runs off of spend exhust gases. And you get a great BOV .
Turbo=con, Turbo has lag it take time to build up presure to get it spooled.

[imported_knowles101]

So with the stock internals on the B18C GSR lets say I do add a turbo what would be my best buy ? and what power gain am I looking at , is there any way to know other than a dyno?

[imported_NineFiftyFour]

Don't let anyone fool you about over/underdrive pulleys.....

If you are lucky, you MIGHT get 2whp from them, BUT the damage they can cause to your engine FAR outweighs the benefits.


If you want to "lighten" the rotating mass, I would suggest an aluminum flywheel and that's it.

Think of it this way.

On the left side of your engine is your tranny. The stock flywheel weighs in at about 16-18lbs. On the right side of your engine is your crank pulley, this weighs in at about 6-8lbs.

When the engine is spinning, both sides "balance" eachother because they are designed that way. IF you replace the flywheel with say a "Fidanza" unit which weighs in at about 9lbs, then you aren't really doing any damage, because you have approximately the same weight on the opposite side. Thus keeping the engine "balanced".

BUT, if you change the crank pulley, to say an "Unorthodox" aluminum unit which weighs in at 1.5lbs, then you are offsetting the balance point and thus you could cause your crank bearings to wear unevenly.

Stock:
Pulley 8 - Flywheel 17

Aftermarket flywheel:
Pulley 8 - Flywheel 9

Aftermarket pulley:
Pulley 1.5 - Flywheel 17

Both pulley and flywheel:
Pulley 1.5 - Flywheel 9

Now, you're probably thinking, "I'll just do both"....

Good idea in theory, but bad idea in reality.... WHY???

The factory crank pulley has a dampner installed between the metal to keep vibrations at a minimum. The unorthodox pulley is machined aluminum. The vibrations that can be caused by the resonant harmonics of aluminum will most likely damage your crank bearings in the long run.

So, is 2 HP really worth it? Not in my opinion...


Lastly, maybe you've thought about just getting smaller alternator and/or power steering pulleys....

Alternator - If you value your battery even slightly, don't do this one. At idle, my voltage dropped below 11.8v at crusing speed (4k rpm) I could only get a 12.3v charge..... NOT a good thing. I killed 3 interstate batteries in about 1 year.


Powersteering - This is OK to get, but you will not see any gains in the HP department at all. If you REALLY want this, it will not do any damage to your vehicle or the PS pump.

HTH

-NFF

[imported_DIYperformance]

Wow, good write up. Sounds like someone did their homework with trial and error.

[cynosurecivic]

i've got unorthadox racing pulleys. im satisified with them. would def. buy again.

[Calesta]

Originally posted by DIYperformance@Jul 18 2003, 10:25 PM
Sounds like someone did their homework with trial and error.

More like common sense and physics, with a little bit of real world study that proved the point.

[Goldenboy]

PM me for a pricing on the underdrive pulleys.
and you can safely run 10lbs on stock internals, just shift a little early.