Effective NA Power Mods

[Vracer111]

Originally Posted by justatroll

I never questioned that reducing mass and/or rotational inertia will give you faster acceleration.


I said it cannot make more hp

You are correct - and that has been what I have said all along, correct? The reason I would put effort into reducing MOI with flywheel and wheels, and regearing the rear end is because it's the easiest way to increase responsiveness of the car, especially if for an NA build. For cost, flywheel + rear end regearing is cheaper than header and you will definitely feel more acceleration down low in the first 2 gears, and with zero tuning required to reap the full benefits. Again, intake and exhaust work is a given for NA build.

I'm just coming from what I've experienced with a track Integra RS (2300lbs with stock power level - that car was on par with the FR-S, but with much better initial acceleration off the line and the B18A motor had characteristics which I would love to have in the FA20. The FA20 is more of a an engine that smoothly builds it speed and doesnt want to change its rpms too quickly, the B18A lived to rev and was much more eager to do so, especially once adding the 8lb racing flywheel - going off throttle was more like gentley getting on the brakes and going on throttle like having an electric motor assist, noticeable change in decceleration/acceleration (the B18A with the flywheel literally goes up and down through the rpms, in gear, about twice as quick as the stock FA20 - I'm sure the weight difference between the two vehicles also helped with that as well.)

The flywheel made a very noticeable difference in how it launched from a stop, and it already had a custom designed and fabbed exhaust/header/intake. Noticeably quicker acceleration plus you definitely felt being forcibly pushed back into the seat at launch. And then when running on track, the motor was much more eager and quicker to run up and down the revs in gear....and that also translates to having quicker and more precise control of the car through the turns.

When it comes to building a NA setup, a properly designed lightweight flywheel, low MOI wheel design, and rear end gearing change will always be part of it for me - just makes sense and enhances the cars reflexes. The TRD/Toda flywheel is on my highly want list along with a 4.56 ratio ring and pinion. I've also ended up going to a 'skinnier', lighter, and slightly smaller diameter tire setup than stock which suits the car better. A more responsive car is what I'm looking for in an NA build. I'm one of the owners who is more than content with the stock power level of the FR-S - It just needs less mass and a little quicker reflexes.

[Ultramaroon]

Originally Posted by gramicci101

Don't you have to say "no homo" before you just go caressing another man's Pekingese?

Only if you mean it.

( ͡° ͜ʖ ͡°)

[Cole]

Originally Posted by MuseChaser

I've always liked that question. Unfortunately, it's based on fallacious logic. The wheels on an airplane, unlike a wheel-driven vehicle (engine-to-transmission-to-differential-to-axle-to-wheel or similar) are not driven at all; they just idle or "coast" like the wheels on a shopping cart. An airplane-sized treadmill would have no effect on the speed of the aircraft; the aircraft's speed (caution--- oversimplification ahead) is governed by the thrust of the air rearward by the propellor. The aircraft would move forward independent of the speed of the treadmill. As the airspeed increases, the wheels would spin proportionally faster than the treadmill until the airplane would eventually lift off in the same amount of horizontal distance it would have lifted off if the ground beneath it had been stationary; it's airspeed across the wing that determines the lift. Now, if the treadmill/wheel interface creates an appreciable amount of drag, then it would take longer to achieve the required airspeed for take off, but there's no way a treadmill COULD "match the wheel speed... so that no forward motion is achieved" simply because the wheel speed would have no effect (other than friction of the wheel to treadmill interface and bearings) on forward motion. That plane is going forward, no matter what, unless the wheels are being prevented from rotating by brakes or wheel chocks.

Soo... fun question, but faulty premise.

Yeah, there's a bit more to it, but that's the gist of it.

Barry

Yes, but we're talking entirely theoretical here. If there's no air moving over and under the wings, no lift can be generated. Like if you're on a treadmill that's matching your speed exactly and you're wearing a parachute. Is that parachute going to fill up with air?

[MrFisty]

Wtf why are you guys talking about airplanes and treadmills and hookers?

[Ultramaroon]

Originally Posted by Vracer111

...I'm one of the owners who is more than content with the stock power level of the FR-S - It just needs less mass and a little quicker reflexes.

This is the only argument that makes sense. I only notice the flywheel in first and rev-matching.

Replacing the harmonic balancer and stock driveshaft? Whole lotta nope there.

[Ultramaroon]

Originally Posted by Cole

Yes, but we're talking entirely theoretical here. If there's no air moving over and under the wings, no lift can be generated. Like if you're on a treadmill that's matching your speed exactly and you're wearing a parachute. Is that parachute going to fill up with air?

Only if the treadmill gets shoved out the ass of a flying C-130.

[Ultramaroon]

Originally Posted by MrFisty

Wtf why are you guys talking about airplanes and treadmills and hookers?

Because we fucking feel like it!

[Cole]

Originally Posted by MrFisty

Wtf why are you guys talking about airplanes and treadmills and hookers?

Hey, gtfo of here with your logic and on-topicness. No one asked for that.

[Vracer111]

Originally Posted by go_a_way1

Quick FYI there engines don't make any more power after roughly 7800 rpm they die out. You can not do cams that are even remotely worth while without changing the stroke and pistons to prevent them from kissing the valves.

I would like to get a spare FA20 motor and take my time and do an NA build on it, been looking at the NA build thread off and on. I don't need it to rev too high, just fast - 8K redline is all I'm looking for, as long as its noticeably quicker at spinning up and down than a stock unit...

[Spartarus]

Originally Posted by Cole

All these pulley debates remind me of the great physics question:

If you put an airplane on a treadmill that matches the wheel speed of the airplane perfectly so that no forward motion of the plane is achieved, will it take off?

Ok, I'm late to this party but I have to correct this.

The question is predicated on a flawed assumption.

The presence of a treadmill is irrelevant. The airplane doesn't use its wheels to achieve forward motion. The fact that they're rolling on a treadmill is irrelevant.

When you apply power to the engine, Jet, turboprop, plain ol' reciprocating engine bolted to a propeller, the plane will move forward. It doesn't matter what the wheels are doing. It doesn't matter if it's on a treadmill that's going 1000 miles per hour. The wheels are freewheeling. You can't make enough drag through the treadmill to stop the plane. That's the minimal rotational drag of a wheel bearing vs the forward thrust of the plane.

It's a question that hands you a flawed assumption and asks you to answer a question based on the flawed assumption. That's the definition of a trick question.

Imagine this scenario.

Imagine you're on roller skates on a treadmill, and someone hands you a rope. If you pull the rope, you go forward. It doesn't matter if the treadmill is going a billion miles an hour. You go forward when you pull the rope. The treadmill can not match your forward speed, the same way a treadmill can't "match" an airplane's forward speed, they are not applying the same force. They can't apply the same force. It's impossible. They are applying different forces to different mediums that don't balance out.

[CSG Mike]

Originally Posted by justatroll

So how does the rotational inertia of the flywheel and crank affect the torque measurement at constant RPM (NOT accelerating)?

Answer: It doesn't.

I'm gonna let you think about that one

There may be a constant RPM, but it doesn't mean there are no forces involved

[go_a_way1]

Originally Posted by Vracer111

I would like to get a spare FA20 motor and take my time and do an NA build on it, been looking at the NA build thread off and on. I don't need it to rev too high, just fast - 8K redline is all I'm looking for, as long as its noticeably quicker at spinning up and down than a stock unit...

Okay I see what your going for. I say do it! I would love to build a motor but I am a FI guy so my motor would be for that, but nothing beats the feel of a good NA motor

[go_a_way1]

Originally Posted by MrFisty

Wtf why are you guys talking about airplanes and treadmills and hookers?

You must live under rock. Welcome to FT86Club

Brb getting more dis thread gettin gud

[MrFisty]

If I were to go NA, I would start with some weight reduction and add about four cylinders.

You could also raise the compression. Pretty low as is.