Lower pulley HP added

[sharke]

It seems odd but most sites seem to ignore how much horsepower the lower pulley adds and only state that it adds 4 lbs of boost. On my old car it was about 10hp per pound of boost but i don't know of any rule on cobras.

Point being, how much horsepower does the lower pulley add on a car with just the basic mods.

 

[rdsnk46]

It's 10% more than the boost your currently running 21psi then add 2.1psi for 23.1. Also I think the HP gained isn't as great as the torque that is gained by reducing the paracitic drag on the motor.

 

[sharke]

It's 10% more than the boost your currently running 21psi then add 2.1psi for 23.1. Also I think the HP gained isn't as great as the torque that is gained by reducing the paracitic drag on the motor.

I'm not trying to attack the messenger here but I'm a little confused.

I am pretty sure my car is making 13 psi and that the lower pulley adds 4 lbs?

Also if torque is gained then HP is gained. HP is just (Torque * RPM)/5250

 

[Leonard 95]

I don't know all the math, but you gain alot more tq than hp from what I have been seeing, its a nice tq curve though with the lower.

 

[Willie2]

i read an article on this in one of my many MM&FF's stacked in my restroom floor....from what i can remember the test car saw 3.xx lbs more boost

i want to say it was on the project vapor trail car. they also changed axle backs. maybe TB's too

but the point of the article was to find 50 hp, and they did... hope this helps

 

[kyl]

I wish more people made lower pulleys. I buy one in a heart beat if a 4 pounder was $350 or less.

Id much rather switch the lower and belt then the upper and add a tensioner.

 

[Alloy Snake]

I thought it was 10% larger,But the equation works,I was at 12.87 and now 14.3-15 psi depending on weather.Torque is where its at-I asked my tuner why I didnt gain the boost-He said what I did gain was very efficiant.

 

[mixxer]

Its really only good for 3 lbs or so.

 

[littlejohn]

The thing is, you need to go to a larger TB at the same time, b/c the stock one becomes a restriction at this point.

You will gain 10-15 rwhp/50+ lb-ft with it alone.

With the TB also total gains are 30+ rwhp/50+ lb-ft.

I have this setup, there was a big step up from a stage 2, but it does heat soak faster with spirited driving. I have to do the C+R h/e yet.

 

[sharke]

The thing is, you need to go to a larger TB at the same time, b/c the stock one becomes a restriction at this point.

You will gain 10-15 rwhp/50+ lb-ft with it alone.

With the TB also total gains are 30+ rwhp/50+ lb-ft.

I have this setup, there was a big step up from a stage 2, but it does heat soak faster with spirited driving. I have to do the C+R h/e yet.

That is my plan of action. I want to do more "stages" of mods on the car. I want to do tb + lower pully in one stage and I want to do drive shaft and 3.73 in the other stage.

After that I think it will have as power as I can handle with my ability.

 

[Hissssss]

After that I think it will have as power as I can handle with my ability.

:bs:..........thats what we all say...and then the CC comes out again...:rollseyes

 

[sharke]

:bs:..........thats what we all say...and then the CC comes out again...:rollseyes

I would agree if there were more simple mods to do. On this car after you do the basics it jumps to mods that require so much supporting hardware that i would have a hard time stomaching it even if I thought I could control it. I like to stick with true bolt ons.

 

[sfadchi]

Yeah one would think this would be enough power!

But then I had to go out and throw some NOS on it! It produced so much power the straps on the dyno could not stop it from skipping on the drum. Trust me when I said this, you are never done spending money on these cars!

 

[sc2000gt]

i currently have a steeda cai 2.7 pulley and 93 octane tune. i also have a magnaflow 3" catback. if i were to change just the lower pulley would that require a retune? my programmer allows me to adjust timing. could i just pull 2-3 degrees to keep it from detonating from the extra boost at low rpms?

 

[Alloy Snake]

You would need a retune and get the metco upper to get it down to 2.6-Or better yet get the VMP front snout and run a 2.4 with a 10% lower.You would also need supporting cooling mods.The need for a tune would be based on more air flow-From the supercharger spinning faster-This is also the time to add a better throttle body.The exhaust is irrelevant as far as a tune goes-Stock exhaust flows quite well just too quiete.

 

[EX1]

i currently have a steeda cai 2.7 pulley and 93 octane tune. i also have a magnaflow 3" catback. if i were to change just the lower pulley would that require a retune? my programmer allows me to adjust timing. could i just pull 2-3 degrees to keep it from detonating from the extra boost at low rpms?

you would need a re-tune. The extra boost is going to alter your air-fuel ratio among other things

 

[bloomy63]

Less parasitic drag with 10% overdrive pully

It's 10% more than the boost your currently running 21psi then add 2.1psi for 23.1. Also I think the HP gained isn't as great as the torque that is gained by reducing the paracitic drag on the motor.

I'm trying to understand how this works. How does a bigger pulley, which is harder to spin than a smaller pulley reduce paracidic drag on the motor?

I'm thinking on how people install underdrive pulleys for their accessories to gain more power at the wheels.

Or on a bicycle if you want to go faster, you shift to the bigger pulley on the front, which makes you go faster, but makes it harder to pedal?


Torque = power
Horsepower is defined as work done over time.

So the reason why the HP gain is lower than the torque is because the engine has to work harder (spinning the supercharger with a bigger pulley) to get more work done in a given time.

just thinking out loud.

 

[Alloy Snake]

A bigger gear basically- at the crank where there is 100% horsepower v/s going through the smaller pulley upside-I dont know but it just works,I think the formula is E=MC squared

 

[sharke]

I'm trying to understand how this works. How does a bigger pulley, which is harder to spin than a smaller pulley reduce paracidic drag on the motor?

I'm thinking on how people install underdrive pulleys for their accessories to gain more power at the wheels.

Or on a bicycle if you want to go faster, you shift to the bigger pulley on the front, which makes you go faster, but makes it harder to pedal?


Torque = power
Horsepower is defined as work done over time.

So the reason why the HP gain is lower than the torque is because the engine has to work harder (spinning the supercharger with a bigger pulley) to get more work done in a given time.

just thinking out loud.

I think the lesser parasitic drag comes from the pulley being much lighter.

As for the extra boost... A smaller pulley spins faster because for every x feet of belt you used to get x rotations on the bigger pulley but with a smaller circumference x feet of belt causes more full rotations of the smaller circumference and the belt moves at the same speed. So if i had to guess the a larger gear that isn't the pulley causes the belt to move faster and also more rotations of the SC pulley.

As for HP gain being less than TQ that means that the gain in torque is at the bottom of the curve since HP is just (TQ * RPM)/5250. So what is most likely happening is that the extra boost at the top is really hot and not as efficient as the extra boost at the bottom.

 

[bloomy63]

weight of crank shaft dampners

I think the lesser parasitic drag comes from the pulley being much lighter.

The 2008 ford crank dampner weighs 10.5 lbs Part# m-6312-svt

The innovators west 10% OD pully weighs 11.2 lbs.