Power to weight Ratio? Car? Vs Supra

[Turbo Habanero]

So i was driving along last night and ran into a 07 350z decided i was going to race the guy from a dig.
Outcome we were neck and neck till about 60 where i pulled away.

So it got me to thinking that if my car wieghs about 3800 and the Z is about 3350 (D-450) and stock a 07 Z has 306hp 268Trq im assuming these numbers are Flywheel (took them from internet sources) how much HP/Trq would i have to have to beat the Z?

I don't think theres anyway im making that much power to have more then the 350 and thats why im confused but on a reg. basis i can beat them around here.

my mods are in Sig and i was only running 8-10psi

 

[Suprapowaz!(2)]

I don't know about power, but with your mods at 10-11psi on a manual boost controller I was running 13.70's@103 2.1sixty footers.
That was on street tires, stock CT26 with stock elbow, stock fuel system, Cartech intercooler, Cartech 2.75" DP, HKS 75mm catback, and Saab BOV mod. I never knew how much rwhp I was putting down.
Have you ever ran your car at the dragstrip? I'd imagine your car would be a little quicker having a better exhaust than I did.

 

[radiod]

Here's the figures I found for a stock 350Z:

2007 350Z Base Coupe 6MT 13.7 @ 104

I'd say with a good exhaust, some intercooler piping, and a manual boost controller that's pretty doable for keeping up in a straight line.

 

[GrimJack]

You've left out a few rather important factors in your estimates. First off, the listed curb weights are always dry, no fuel, often no other fluids, and certainly no driver. You can realistically add ~350 pounds to that. Then there's the fact that their engine likely isn't running as well as it was when it left the factory, and might not have been making the advertised power to start with.

With realistic weights at full factory power, you'd need 267whp to be competitive. With a 10% loss of power on their part due to wear, you'd only need 241whp to be competitive.

 

[te72]

Grim, do they do curb weights differently in Canada? I was under the impression that curb weight was as driven, with full fluids. I believe our cars have a 750lb cargo/passenger capacity, and if I remember correctly, the door sticker says something along the lines of 4450lbs. Take out 750lbs, you end up ~3700lbs, which is consistent with what I've learned from the scales on my car...

 

[GrimJack]

To be honest, I don't really know. I'm basing that off the fact that car manufacturers never can seem to keep their fingers out of the 'fudging' pot when it comes to specs.

Even if we take the non-driver weight out of the equation, that still leaves the numbers at 253 - 281whp.

 

[Turbo Habanero]

I was running 13.70's@103 2.1sixty footers.
I never knew how much rwhp I was putting down.
Have you ever ran your car at the dragstrip? I'd imagine your car would be a little quicker having a better exhaust than I did.

Not yet.. But i honestly dont believe its 13sec quick. but idk i do live in Tucson and cars always run slower out here.

---------- Post added at 03:15 PM ---------- Previous post was at 03:12 PM ----------

that still leaves the numbers at 253 - 281whp.

This is what confuses me the stock Z lets say after he's put some miles on the car and wear and tear hes only making 270hp but that car still wieghs alot less then ours? so we would need more then 270 to keep up correct?

Check the link out below its a Power to wieght ratio Calculator.

http://www.dragsource.com/index.php?navselect=calculators&calctoview=7

---------- Post added at 03:19 PM ---------- Previous post was at 03:15 PM ----------

Here's the figures I found for a stock 350Z:

2007 350Z Base Coupe 6MT 13.7 @ 104

So here's what i figured with the link above.

Lets say

Z = 3400lbs/280hp Power to wieght of 12.1

For a supra to be the same Power to wieght

Supra 3700lbs/305hp Power to wieght of 12.1

 

[Turbo Habanero]

quick video of a 60-120 pull.

[video=youtube;eWVvzlYmUpc]http://www.youtube.com/watch?v=eWVvzlYmUpc[/video]

 

[hvyman]

Some of those like to burn oil as well. So who knows how worn the motor is.

And then there is always the driver. Could have been a 16 yr old kid.

Or he could have been 300lbs with a full tank and lots of weight in the car.

 

[GrimJack]

Stock '07 Z in good shape dynos 260 to the wheels. In average shape drop that by 10%, or 234whp. And you're only figuring 50lbs for the driver? Were you racing a 6 year old girl? How about figuring 175 lbs for an average male, fully dressed.

That makes the calculation (3339 lb car + 175 lb driver) / 260 = 13.51538 lbs / hp

or for the one in less than perfect shape:

That makes the calculation (3339 lb car + 175 lb driver) / 234 = 15.01709 lbs / hp

To get to that in your Supra, do the reverse:

Good shape Z:
3800 lb Supra / 13.51538 = 281.1611whp required

Less perfect Z:
3800 lb Supra / 15.01709 = 253.045whp required

 

[Turbo Habanero]

So you think a four year old car could have up to a 70hp lose. Imagine mine being 22years old :-/

 

[hvyman]

All depends on how worn the motor is.

 

[Turbo Habanero]

So what do you think a safe bet is for my car 265-275? And that's enough to make a 3800lb car run a 13sec 1/4 mile

 

[GrimJack]

Not really, no. Only a bit of that comes from wear and tear. The vast majority of it comes from the difference between BHP, or Brake Horsepower, and WHP, or Wheel Horsepower. An average RWD car loses ~15% to drivetrain loss between the engine flywheel and the tires. Car manufacturers advertise BHP, because it's bigger, and bigger sells more cars. In the real world, we care about WHP, because that's what we actually have at our disposal.

306 hp = BHP
260 hp = WHP (15% loss)
234 hp = WHP after wear and tear (another 10% loss)

 

[Turbo Habanero]

Yeah I know.

So the 232 are car is stock was that wheel or flywheel ?

 

[hvyman]

Flywheel. Im not aware of any factory hp rating that is to the wheel.

So its about 190-200ish to the wheel new.

 

[Pokey2301]

my mustang stock ran a 14.9 at 93 mph sir, so with the altitude, id say it was right on par for a 14.3

and your car seems healthy, did you talk to the guy in the Z to get some more info?

either way good run though

 

[Albert]

why Would you run slower in tucson, Everytime I drove down to tucson from PHX my 1J seem to feel quicker...

 

[Turbo Habanero]

why Would you run slower in tucson, Everytime I drove down to tucson from PHX my 1J seem to feel quicker...

It seems to be the other way around for us Tucson guys we always run faster at Firebird then SIR

 

[Pokey2301]

why Would you run slower in tucson, Everytime I drove down to tucson from PHX my 1J seem to feel quicker...

phoenix is lower than tucson, so dont understand why that would happen

Tucson is around 2700 ft and SIR is closer to 3000 ft