Need Help getting power without Forced Induction
 

Hello,

Was wondering what I can do to get the most power out of my scion without getting a Turbo or supercharger. Please let me know what you guys think.

Thank you,
-GreaseBall

What is your budget?

Headers
Tune
E85
Crawford BPB
Drop In Filter
Exhaust
Lightweight Crank Pulley
Lightweight Drive Shaft
Lightweight Wheels

http://www.ft86club.com/forums/showthread.php?t=81493

All described here.

4.56 final drive swap if you have a manual makes a world of difference.

Engine swap, maybe

I wouldn't run the BPB with E85. It truncates power above 6500rpm where E85 maps keep building power. But I agree with everything else (maybe not the crank pulley) :)

I have read about some of the dangers of the lightweight crank pulley regarding balance on both sides of the crank... why wouldnt a light driveshaft be an issue also?

Because with the factory pulley, there is a rubber isolated harmonic damper. Since LW pulleys don't have them, you are eliminating this very important component that is there to move the major crankshaft harmonics (which result in crankshaft twisting) to occur at revs higher than your operational engine speed range (800-7500rpm)

so... is it not possible for someone to make a lightweight pulley with the harmonic balancer?

I've seen some with them in domestic car markets. It's not an easy thing for a normal tuning company to do since it involves measuring angular crankshaft deflection at a wide range of engine speeds and then designing the correct damper. OEMs have entire NVH teams that do this for a living. It's not something you can eyeball :)

Back in the late 90s we released a lightweight underdrive pulley for the EJ25 in the Impreza 2.5RS. I was lucky enough to have a customer who works in the NVH department at Rousch. He tested the engine for harmonics with the stock pulley and our pulley (no harmonic damper) only to find that the stock pulley moved the major harmonics above 7500rpm where it would otherwise be at 7000rpm. It wasn't a big deal for us since we rev limited that engine to 6900rpm.

Crank pulley, drive shaft, and wheels won't make any more power.


Tune, header, E85 will be the biggest power adders.


Still, if you want real power, you're going FI...

No but they do reduce rotational mass resulting in more power at the contact patch and better acceleration. Dynodynamics can actually measure the power gain from lighter wheels and tires, saw it many times when i used to tune on one.

That is about the only one that will really be felt as well. Removing unsprung weight is great, and lighter wheels/tires will allow you to accelerate faster and brake shorter.


But you're STILL not really making more power, it's just not as much drivetrain loss.


Crank pulley: As already stated, not a great idea, plus it's a very minor weight loss close to the axis of rotation.


Driveshaft: Same as crank pulley as it's all close to the axis of rotation. Also, I have yet to see a lightweight 2 piece driveshaft (yes they can be made). Keep in mind that a single piece would be far cheaper for them to make, and in a car with very little sound insulation, NVH is not the driving force behind their decision to use a 2-piece. The other obvious reason is driveshaft critical speed...


Flywheel: Now we're talking. Lots of weight and it's far away from the axis of rotation. Downside is that it's harder to replace, makes the car a bit of a pain to daily, and if the car is drag raced, the clutch can weld itself to the steel inserts (on an aluminum flywheel, this is not so much an issue on lightweight steel or cromoly flywheels).

Here we go again with the lightweight crank pulley nonsense.

I've been running one for two years with 0 issues. The engine is already balanced. If anything, it revs slightly more freely with it. Not a major change, but looks nicer than the heavy stock pulley.