In for the long haul Ultimate NA build thread.

[HUNTERANGEL121]

Originally Posted by sato

Thanks for the gentle reminder



I know there are four cams instead of two, but wow

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You're paying for four cams but if you them to each other it's the same size as one normal cam on an i4. That's how it works, right?

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[Summerwolf]

Pretty much, just two cylinders next to each other instead of four.

Unfortunately, coming from the "LSx" community.... 1000+ for cams is rediculous, lol.

[celek]

Originally Posted by Summerwolf

Pretty much, just two cylinders next to each other instead of four.

Unfortunately, coming from the "LSx" community.... 1000+ for cams is rediculous, lol.

Much better option than HKS at $1800 though

[solidONE]

Originally Posted by Tim Radley

I tried an early soft version and with other changes gained 25bhp.
Have got a hotter set to try but just not had time to fit them. I'll most likely wait until I fit a turbo to be fair as my time with the car is very limited.

It would be nice to know how much gains yielded by the cams themselves. I've gained about 30whp on "other changes" with stock cams, so when you say +25bhp with cams and 'other mods' its not saying too much.

[celek]

Originally Posted by solidONE

It would be nice to know how much gains yielded by the cams themselves. I've gained about 30whp on "other changes" with stock cams, so when you say +25bhp with cams and 'other mods' its not saying too much.

1. Brake Horse Power (bhp)

This is the power output of any engine measured at the engine's flywheel. (A flywheel is a disc with teeth on it. It's connected to the rear of the engine and its purpose is for the smooth transfer of power to the transmission from the engine.)
2. Wheel Horse Power

Unlike bhp, whp is the power output measured at the wheels. This is the information a dyno run provides and usually reads around *15 per cent less than the power measured at the engine (bhp) - this is because power is lost in the driveline (including clutch and transmission). *Four-wheel drive cars lose between 20-25 percent of their quoted bhp figure because of the increased friction.

Advanced info

The term brake horsepower (bhp) refers to a device called ‘Prony Brake’ (invented by Gaspard de Prony), which was used to measure engine power in the early 1900s. 2. You don't need to increase an engine's bhp to get an increase in a vehicle's whp. You can achieve higher whp by reducing the rotational mass in your drivetrain, such as the wheels, tyres, brakes, clutch, flywheel, etc.

In short BHP is an actual increase of output at the engine, whereas WHP can be changed not only by BHP but also mass reduction.

[Gear_One_Performance]

The other nice benefit is being able really ring the motor out without losing efficiency. Being able to stay in gear 1000 rpm longer than your competition is a nice plus.

[solidONE]

Originally Posted by celek

1. Brake Horse Power (bhp)

This is the power output of any engine measured at the engine's flywheel. (A flywheel is a disc with teeth on it. It's connected to the rear of the engine and its purpose is for the smooth transfer of power to the transmission from the engine.)
2. Wheel Horse Power

Unlike bhp, whp is the power output measured at the wheels. This is the information a dyno run provides and usually reads around *15 per cent less than the power measured at the engine (bhp) - this is because power is lost in the driveline (including clutch and transmission). *Four-wheel drive cars lose between 20-25 percent of their quoted bhp figure because of the increased friction.

Advanced info

The term brake horsepower (bhp) refers to a device called ‘Prony Brake’ (invented by Gaspard de Prony), which was used to measure engine power in the early 1900s. 2. You don't need to increase an engine's bhp to get an increase in a vehicle's whp. You can achieve higher whp by reducing the rotational mass in your drivetrain, such as the wheels, tyres, brakes, clutch, flywheel, etc.

In short BHP is an actual increase of output at the engine, whereas WHP can be changed not only by BHP but also mass reduction.

ORLY? lol

The WHP I yielded form "other changes" over baseline use the same or similar drive-line components. Same model clutch, flywheel, driveshaft, diff, halfshaft, hubs, studs etc. Tire and wheels were slightly different. 17x8 RPF1 with 225 tires for baseline, 17x9 RPF1 with 255 tires used when measuring WHP gained from (other mods). I'm sure if BHP was measured with the baseline and after my "other mods" on stock cams it would still be more than +25bhp.

Point is I'd like to see the gains from the cams alone, with all else the same or with only cams and tune being different.

[jarnojvv]

Just a question: how does weight reduction increase whp? It surely only improves response and feeling. It would be interesting to see how much focused mods can reduce the driveline friction to increase the real whp.

[FRS Justin]

Originally Posted by celek

Only downside is valve to piston clearance. The longer they are open more chance of interference. Stock pistons probably wont work on every cam. Even HKS says you can not use their cam with stock pistons, they say you should buy the high capacity kit.

Hey Chris


I was researching cams for my backup motor (yes another one) and found this . Excellent info on FA20 camshaft specs. It has piston to valve contact clearances.


I know it won't apply 100% because of your pistons but it might help if you decide to go with a custom set of cams like I am.


http://dsportmag.com/the-tech/tomei-...0-flat-four/3/

[Captain Snooze]

Originally Posted by jarnojvv

Just a question: how does weight reduction increase whp? It surely only improves response and feeling. It would be interesting to see how much focused mods can reduce the driveline friction to increase the real whp.

[FRS Justin]

Originally Posted by jarnojvv

Just a question: how does weight reduction increase whp? It surely only improves response and feeling. It would be interesting to see how much focused mods can reduce the driveline friction to increase the real whp.

Google is a wonderful thing....


http://www.w8ji.com/rotating_mass_acceleration.htm


copy and paste to browser

[celek]

Originally Posted by jarnojvv

Just a question: how does weight reduction increase whp? It surely only improves response and feeling. It would be interesting to see how much focused mods can reduce the driveline friction to increase the real whp.

If you roll a 200lb boulder up a hill it takes energy. Now if you reduce its mass to say 50lbs it takes less energy and can be rolled faster.
Same amount of power put behind it the less the person has to work same with the engine.

Still making 200HP stock but reduced weight especially in rotating assembly results in less power lost in the drive train. Less parasitic loss in the drive train interpolates to more WHP

[churchx]

celek: only losses in friction of gears/bearings and tire-road affect whp readings. And those are mostly same with or without lightened rotational components. Change of rotational mass affect only time at which certain speed is reached, not how much energy is needed once it gets up at said speed. In your example if you move it to dyno, then it's not the wheel of 200lb or 50lb weight, but rather that dyno brakes car wheels at four time the force, which is not the case. With same dyno "braking" readings should be same for both 200lb & 50lb wheels, with exception of how long heavier one was spun up/accelerated to max speed.

[celek]

Originally Posted by churchx

celek: only losses in friction of gears/bearings and tire-road affect whp readings. And those are mostly same with or without lightened rotational components. Change of rotational mass affect only time at which certain speed is reached, not how much energy is needed once it gets up at said speed. In your example if you move it to dyno, then it's not the wheel of 200lb or 50lb weight, but rather that dyno brakes car wheels at four time the force, which is not the case. With same dyno "braking" readings should be same for both 200lb & 50lb wheels, with exception of how long heavier one was spun up/accelerated to max speed.

Really depends on perception but I agree. One of the things in my build is REM polishing of the gears, technically not only lightening the gears by removing tiny bits of rough material including removing friction causing micro peaks. As friction generates heat removing them reflects prolonging transmission life.