Jackson Racing Supercharger Owners Thread

[mrg666]

Originally Posted by CSG Mike

AUC works against us.

AUC is "Area Under Curve", right? What aspect that determines the AUC is more important? Rev range on the horizontal axis or power peak on the vertical axis? I think, given the same weight, a more powerful car can have a disadvantage if it needs to shift before the other less powerful car keeps building up the power on a wider rpm range. Do you agree?

[Kodename47]

Originally Posted by mrg666

AUC is "Area Under Curve", right? What aspect that determines the AUC is more important?

If 2 cars have the same peak power, similar gear ratios but one has more torque over the entire RPM range then that one will be quicker. This is undoubtedly the case with V8 engines with similar peak power to weight ratios. Throw in longer ratios with more torque to put down then there's no chance.

[CSG Mike]

Originally Posted by mrg666

AUC is "Area Under Curve", right? What aspect that determines the AUC is more important? Rev range on the horizontal axis or power peak on the vertical axis? I think, given the same weight, a more powerful car can have a disadvantage if it needs to shift before the other less powerful car keeps building up the power on a wider rpm range. Do you agree?

S2000 + C30-94, not enough fuel pump (hence the torque taper)


FA20 + C30-94 JRSC + header (lower line is generic UEL + E85, higher line is Ace + E70)



Notice the S2000 has more area under the curve, particularly noticeable on the torque side.

[brzaapi]

Originally Posted by CSG Mike

S2000 + C30-94, not enough fuel pump (hence the torque taper)


FA20 + C30-94 JRSC + header (lower line is generic UEL + E85, higher line is Ace + E70)



Notice the S2000 has more area under the curve, particularly noticeable on the torque side.

Miikkkee.....don't show me this crap. I am trying to stay NA in my S2k, and with the BRZ going bye bye in the future it just makes me want to FI the Honda that much quicker. Good god, look at how that builds up to 400+ whp.

[Canehda]

Originally Posted by CSG Mike

I would, at the minimum, recommend logging to see if everything is okay.

did a bit of logging today, i think I'm going to go back for a bit of an update tune as Ive noticed that my LTFT is trending to more negative values than i would like meaning I'm running pretty rich. Will give my tuner a chance to look at my O2 sensor read outs to check on their health which may be the reason for my very high negative numbers

[Irace86.2.0]

Originally Posted by gtengr

When there are dramatic differences in weight, velocity becomes a relevant factor in the power to weight ratio because pure horsepower is more important when the wind resistance begins to exceed the rolling resistance. Assuming 14.4 lbs/hp in a 2800 lb car and a 3800 lb car, that gives 200 hp and 264 hp, respectively. If we assume both cars have roughly equal aero, and 100 mph is sapping 50 hp from each, then the 2800 lb car now has a power to weight ratio of 18.7 lbs/hp and the 3800 lb car is at 17.8 lbs/hp based on power available to accelerate the car. As velocity increases, so would the gap in the power to weight ratio.

Kinda like cars vs motorcycles. Motorcycles don't have the torque like cars do even if they do have huge power to weight ratio, so they can't hit the same top speeds.

[Irace86.2.0]

Originally Posted by CSG Mike

The problem is, the power build is so smooth, that you don't really feel it when you do long drawn out pulls. If you're at 6500 rpm and you punch it, you're gonna feel it.

Is it so smooth or is it because the torque curve isnt flat?

Torque is force times distance of lever arm. Force is mass times acceleration. Acceleration is the change in velocity or distance over time. A large, flat, torque curve would feel like a kick in the pants at any moment the foot is dropped, and that acceleration or change in velocity would feel constant or consistent. In contrast, the acceleration or force with the JRSC would not feel high at the start of a long gear from low to high rpms. Instead on gaining 10 mph per second with a flat curve, the JRSC might gain 2 then 4 then 6 then 8 then 10. As you can see the power curve would still be linear but forces wouldn't be felt until the end of the rpms. The force behind gaining 10mph per second or maybe 8 is what feels like a knock in the pants.

To me, this is why it may feel smooth. Because the forces build gradually and are smaller at lower rpms so they don't shock the driver with the feel of instant torque unless the driver drops a gear to throw the rpms into higher rpms where there is more torque.

[CSG Mike]

Originally Posted by Irace86.2.0

Is it so smooth or is it because the torque curve isnt flat?

Torque is force times distance. Force is mass times acceleration. Acceleration is the change in velocity or distance over time. A large, flat, torque curve would feel like a kick in the pants at any moment the foot is dropped, and that acceleration or change in velocity would feel constant or consistent. In contrast, the acceleration or force with the JRSC would not feel high at the start of a long gear from low to high rpms. Instead on gaining 10 mph per second with a flat curve, the JRSC might gain 2 then 4 then 6 then 8 then 10. As you can see the power curve would still be linear but forces wouldn't be felt until the end of the rpms. The force behind gaining 10mph per second or maybe 8 is what feels like a knock in the pants.

To me, this is why it may feel smooth. Because the forces build gradually and are smaller at lower rpms so they don't shock the driver with the feel of instant torque unless the driver drops a gear to throw the rpms into higher rpms where there is more torque.

What you're feeling is impulse or jerk.

[Irace86.2.0]

Originally Posted by CSG Mike

What you're feeling is impulse or jerk.

Why use synonyms for force?

Im describing low end torque/force and a flat curve or constant force vs a car that has variable force that builds low to high. Kinda like the difference between a Tesla and most vehicles where the force hits instantly and constantly; it sends you against your seat and the pressure against you feels constant like someone tossed a fifty pound blanket instantly over your body. The JRSC would feel like a five pound blanket is weighing against your body at first and is slowly getting heavier and heavier pushing you into your seat more and more until at peak rpm it finally feels as heavy as a fifty pound blanket. The JRSC would feel far less intense and much more gradual. In a way, your body can prepare for it like warming up to faster and faster pitches with a baseball than getting a surprise pitch at 100mph with no warning.

Im sure this makes for an interesting and maybe unpredictable driving experience. Yes more rpms means more torque, but without a flat torque curve it may be hard predicting how much force the driver will be getting.

[CSG Mike]

Originally Posted by Irace86.2.0

Why use synonyms for force?

Im describing low end torque/force and a flat curve or constant force vs a car that has variable force that builds low to high. Kinda like the difference between a Tesla and most vehicles where the force hits instantly and constantly; it sends you against your seat and the pressure against you feels constant like someone tossed a fifty pound blanket instantly over your body. The JRSC would feel like a five pound blanket is weighing against your body at first and is slowly getting heavier and heavier pushing you into your seat more and more until at peak rpm it finally feels as heavy as a fifty pound blanket. The JRSC would feel far less intense and much more gradual. In a way, your body can prepare for it like warming up to faster and faster pitches with a baseball than getting a surprise pitch at 100mph with no warning.

Im sure this makes for an interesting and maybe unpredictable driving experience. Yes more rpms means more torque, but without a flat torque curve it may be hard predicting how much force the driver will be getting.

Jerk is the derivative of acceleration. It's not another term for force.

Force over time is acceleration. Change in force over time is Jerk. Force applied over time is impulse, aka the integral of the force over time.

[bfrank1972]

So you're saying anyone who drives a V8 car (mustang,camaro,vette) is an impulsive jerk?

Sent from my SM-N920V using Tapatalk

[brzaapi]

Originally Posted by bfrank1972

So you're saying anyone who drives a V8 car (mustang,camaro,vette) is an impulsive jerk?

Sent from my SM-N920V using Tapatalk

I was not prepared for your post while having my morning coffee, you sir owe me a keyboard.

[Deep Six]

Originally Posted by Kodename47

If 2 cars have the same peak power, similar gear ratios but one has more torque over the entire RPM range then that one will be quicker. This is undoubtedly the case with V8 engines with similar peak power to weight ratios. Throw in longer ratios with more torque to put down then there's no chance.

You can include several of the newer turbo 4 cylinders as well. Our Audi weighs 3200 pounds, makes about 350/350 at the crank but hits peak torque at 1900 rpm. Add in AWD and DCT and it simply leaves my FRS by bus lengths.


Similar results for the 718 S which is a much faster street car than the previous flat 6 versions and I've heard it's a near stalemate with the GT4.

[mrg666]

Originally Posted by brzaapi

I am trying to stay NA in my S2k[/U][/B]

First relax, it is okay. Now, go for it!