Almost stock GTR in th 11s

[SkylineUSA]

Very interesting,

Dude! Your getting a GTR!!

[SkylineUSA]

It helps if I post the link.

http://www.fullboost.com.au/cars/fea...r32_shaun.html

[HellBent]

Wow! That is pretty impressive numbers for any car. I did a lot of crunching on these numbers and at first it looks impossible for the GT-R to rip off tese times, but I must concede that I think there is a lot more at work here than simple HP formulas and E.T.s

First, I am not sure of all the variables. There are a hundred things to considder when making a scientific test of the data. For example, what type of tires was the car running, what was the temp-humidity-barometer, was the car deep staged or only touching the first beam, what altitude was the track at, how accurate were the traps, wind speeds, etc.

That said, I am beginning to think that the Skylines AWD system has a huge impact on the numbers. By the 60 ft times, I think that the AWD and experienced driver are getting the car out of the hole 2/10ths - 4/10ths quicker than a stock tired RWD car. If the RWD cars match the HP calculator numbers then I would have to say that the GT-R's 60 ft times support a 3/10ths of a second advantage on them out of the hole. I would have to believe that the GT-R also gets a cleaner more efficient transfer of power on hard 1-2 and 2-3 shifts possibly gaining another 1/10th or two in the 1/4 mile. That said, the GT-R has already got a 1/2 second advantage in any race.

However, even subtracting (adding .5 seconds to the E.T.) the 1/2 second numbers from the HP calculator figures, the GT-R would still have
to make 387 at the Rear Wheels to run 11.57 in the quarter. In the aritcle they say their car is making 240rw kw or 321 rw hp. That is 66hp difference. With the 10% credit to the GT-R I had mentioned in another post, the differnce would be 101 rw hp difference. Without any credit it would be a 148 hp differnece at the rear wheels. This is not small potatos!

I am in quandry as what to believe. I think there may be an error in the numbers somewhere. Most likely the HP calculator doesn't accurrately take into account the AWD systems and a skillful driver. It would be great to have a dyno day, in conjunction with a track day. Then we could see how HP relates to E.T.s and MPH. I believe the AWD cars need their own algorithim for HP and ET.

Maybe there is a racing or physics guru out there who can answer this question?

Just my 2 cents.

Al

[SkylineUSA]

"That said, I am beginning to think that the Skylines AWD system has a huge impact on the numbers. By the 60 ft times, I think that the AWD and experienced driver are getting the car out of the hole 2/10ths - 4/10ths quicker than a stock tired RWD car. If the RWD cars match the HP calculator numbers then I would have to say that the GT-R's 60 ft times support a 3/10ths of a second advantage on them out of the hole. I would have to believe that the GT-R also gets a cleaner more efficient transfer of power on hard 1-2 and 2-3 shifts possibly gaining another 1/10th or two in the 1/4 mile. That said, the GT-R has already got a 1/2 second advantage in any race."

But, there will be a point where the AWD will be henderance. When that point is, I don't know. Weight transfer is good for the 1/4 mile, unless you preload the GTR to establish contact to the pavement out of the hole its will be just dead weight. Then once the front does settle, its not going to help much anyways , since you will be at speed. Also preloading will cause more friction, eating up more HP. Does this make sense HellBent?

You always have to take Dyno HP numbers with a grain of salt. They are not reliable. Times are reliable. Basically your saying is that the GTR is making more HP than what is showed, right? Or the times are BS. I would be more inclined to say the HP numbers are off.

[Henry]

If you believe that an almost stock GTR can get into the 11`s then you guys amaze me.........Just re-read the article,in standard form the GTR was in the 12`s

My R33 has just recorded a personal best of 11.30sec for the 1/4 and thats with 635BHP at the flywheel.

In the UK we have one car in the 10`s and thats Ronnies R33.

I have purchased from Japan a R32 GTR Drag car that has recorded runs in the 9`s,it arrives in the UK very soon.

Henry.

[Henry]

Hope these come out ?

[Henry]

Here`s the R33

[SkylineUSA]

Hi Henry,

That guy did blow up his engine, if I remember correctly. Maybe he was going downhill, on a cold day, with a 70mph wind behind him?

Is BHP at the wheels? I thought I was told that?

Tony

[HellBent]

Henry,

Great pics and thanks for interjecting another view on the HP vs. E.T. debate. My feelings are that indeed a car with only 321 rear wheel HP cannot dip deep into the 11s. Granted the car has 391 hp at the flywheel, but it should still require over 500 hp to acheive an 11.60 second pass in the quarter.

Your time of 11.30 seconds with 635 bhp sounds pretty accurate, and it is a very commendable time. The HP calculator suggests about 580 hp at the flywheel to achieve an 11.30, so your time is at least in the ballpark. I think the HP calculator is a good tool, but not accurate in every case. Well at least it is a start.

If you have other numbers, from your car in various stages of modification I would be interseted in hearing about them. Also if you have numbers on other similar Skylines, I would be interested in seeing them as well.

SkylineUSA,

The BHP number refers to Brake Horsepower, which refers to the "gross" horsepower an engine produces at the flywheel, it is measured without accessories or other parasitic losses taken into account. This is normally the way power is read from engine dynos, where only the engine is run.

SAE Horsepower is "net" horsepower. SAE HP is also measured at the flywheel, but accesory and other parasitic losses are included in the measurement. Therefore, SAE numbers will normally be lower.

Rear Wheel HP is measured on a chasis dyno which gives a more accurate look at how much HP is making it to the ground. So if you hear someone say they drove their car to a dyno day, they are measuring Rear Wheel HP or "rwhp". RWHP can be used to calculate the SAE HP a car is producing, however one would have to make an assumption as to what are the driveline losses. Driveline losses are usualy estimated at 18%, however manual and automatics are different. The AWD system is probably different as well.

Al

[SkylineUSA]

I have heard a loss of 25% when the AWD is kicked in. Not sure about when it just RWD, I imagine 18% like you mentioned.

[Sidewindr]

Just a point here guys you may have overlooked, in Australia our Dyno Dynamics Dyno's read lower than your DynoJet Dynos. I think it is in the vicinity of 15-20% less from memory. Just FYI

[HellBent]

Sidewinder,

What is the reason for the low reading?

Al

[SkylineUSA]

Like I said, time is the only really way to measure

My Stang only dynoed 250hp@4900 on one. If it would have been in the states I would have seen 280 at least.