Power equals Speed

[poptopclk]

I've read a lot of your posts. Thanks for all the good postings. You'd be my tuners if ya weren't 3000 mi away.


I've been seriously considering the JR SC, 285 HP at the wheel looks tempting.


Was ready to order, sent Jackson Racing an email asking for some specific details and they didn't bother to even reply!


[FWIW Shiv's guys responded in a few hours, (customer service is very important to me)]


"147 stock, 171 with Jackson Racing Supercharger in CARB trim"


I'm no physics professor, but I can't wrap my mind around the thought that 100 extra HP only nets 24 Mph at top end.


I've heard law of diminishing returns, but this is a shocker. Is it aerodynamics or gearing? or have I missed something?

[Captain Snooze]

Originally Posted by poptopclk

Light car + high HP mods + ZR tires & suspension = really Fast

For top speed the "light car" part is pretty irrelevant and you forgot to mention drag. Double the speed square the drag.

[Boxer486]

Originally Posted by poptopclk

I've heard law of diminishing returns, but this is a shocker. Is it aerodynamics or gearing? or have I missed something?

It's only a shocker to those that aren't well versed about how cars go fast. You've missed a lot. It's already been explained to you already. Gearing determines top speed potential, power means nothing without having the gearing to obtain a max speed. Our cars are designed to get 30mpg, not 200+mph.

The aero is really good on this car for high speed compared to most typical stock cars, so they will push higher theoretical speeds for the same amount of power if the gearing is correct. Even with gearing, to push 200 on the flats you'd want to tape up all the seams on the car and minimize resistance in front of the radiator and around the tires. You also won't be doing jack for shit if you are running 255F and 295R which sounds like something a novice who knows little about cars would consider doing even though it's on salt. It's actually harder to go 200 on the salt flats due to poor traction. It's not ideal just because there's a lot of flat land that's open. Even then there are other logistical restrictions and making sure your suspension and chassis can hook up all the power too.


As mentioned above, light is largely irrelevant. In fact, it's detrimental to high speed stability without increasing aero aids which means more drag. Think of all the factory cars that can push 200mph+. Cars like the GTR and Bentley Continental GT. Google how much they weigh.


Our cars are for corner carving, mpg, hauling stuff and occasional track days. If you want 200mph, buy a different car like a Corvette or Viper.

[Captain Snooze]

Adding to @Boxer486's excellent post above while you're Googling how much those cars weigh find out how much they cost. Designing a car to be streetable and being able to be stable and controlable at high speed adds to the suspension design and costs.
Everything's a compromise®

[Reaper]

@poptopclk my hayabusa when stock struggled to break 200mph with 180whp. Yet it takes 500whp on a hayabusa to hit 250mph and there is around 250pounds of aero on the rider.

Sent from my SAMSUNG-SGH-I747 using Tapatalk

[SilverSkyline210]

Originally Posted by poptopclk

Since this sub-forum is where the Power is, 300HP+


WHAT IS THE HIGHEST SPEED ACHEIVED on a FI Twin on a stationary surface ie a track or abandoned airfield ect(not a dyno) since I know none of us here would drive above the speed limit on a public street..


From what I have read the stock maxes out around 142 Mph, the FI no idea.

so this just happened today did it for you

[Boofneenee]

Originally Posted by SilverSkyline210

so this just happened today did it for you

ridiculous.

your going to kill yourself!!!!!!

[bumppinKota]

Originally Posted by Boofneenee

ridiculous.



your going to kill yourself!!!!!!

Like the millage

[SmsAlSuwaidi]

174 or 176, the car was decent at such speeds but my bumper almost flew off, it happened pretty quick, in less than a mile maybe..lol.

[rb6freak]

Originally Posted by SilverSkyline210

so this just happened today did it for you

You sir, are my hero. Back in my younger days, I topped out my NA Celica GTS at 150. I won't be trying this with my BRZ on the street though.

[GotBRZ1691]

Originally Posted by SilverSkyline210

so this just happened today did it for you

Going 168mph with engine pegged at redline and still getting over 20mpgs!!!

You sir are an environmentalist haha

Ive got my stock brz to 125 cannot imagine 168 in a twin!

[tahdizzle]

this is a cool thread :p