Temora 1000m 8th Sept

[Yojimbo]

Jase,

all your calculations are assumptions based on acceleration from optimal gearing over a much shorter distance and lower speed. It does not scale linearly to whatever terminal speed you can imagine.

Aerodynamic drag also increases exponentially with speed.

AND then there was traction issues. any car that ran over 240kph was severly traction limited (some at both ends of the track).

I reckon 300 is big ask no matter what hp you bring to Temora, and 350 - near impossible.

[SL666]

so you are saying a car with 1100 hp needs nearly 1300hp to run 290km/h in the 1/4...?

those GTR's *DO* make power... if you need 'blacktop dyno' proof.

166 mph - http://www.youtube.com/watch?v=sgJp-hLOrNo - same spec engine as the pilatus GTR - but in a heavier car. (1800kg + driver)

same spec running the mile - not quite managing 350 http://www.youtube.com/watch?v=zKr8tG25uCE

they spanked some pretty serious cars to get into the top 5 - several turbo v8's etc.


note - im not saying the pilatus GTR was running in the same spec as above at Temora, but somehow we are now arguing if turbo cars make power or something.

[SL666]

AND then there was traction issues. any car that ran over 240kph was severly traction limited (some at both ends of the track).

I reckon 300 is big ask no matter what hp you bring to Temora, and 350 - near impossible.

you aren't joking - i took drag radials this year - dropped my terminal speed by 2 km/h at the same power, but dropped my times (in conjunction with stall converter) by a couple of seconds.

2011- wheelspin as it shifted third - 2012 with radials, holds full power in 1st.

[NME308]

The answers you need are all contained in what I wrote above - terminal speed over the quarter mile does not change regardless of optimal gearing or not.
A well built and designed engine in times past and the way I do them still has them putting out more horsepower to the dragstrip than what shows up on the dyno because racing a dyno is only useful for racing dyno's. The blacktop dyno shows how well the engine can accelerate a given mass while the chassis dyno shows torque x rpm / 5252!
Turbo's are most definately able to make horsepower I never questioned that - its my preferred method of making horsepower.
That GTR from the above video clip is putting down real horsepower to the track whereas the two GTR's at Temora on the day were not...

Cheers,
Jason

[SL666]

I fail to fathom how you can think that a capri that makes 650hp, runs 137mph, can get stomped into the weeds (top speed wise (like 30 odd km/h)) by the 3 GTR's that also beat it on elapse time, that weigh at least a third more, "aren't putting down real horsepower" - It baffles me.

Assuming that they only run ~137mph too, they are still making well over 800hp - just to run that MPH.


my car -

100% hp = 220km/h at temora
121% hp = 234km/h at temora

so 20% extra power, = 14km/h more...

[NME308]

Sorry guys I didn't enter this thread to get toyota nickers in knots - just have a laugh at the stated outputs of a gaggle of nissans vs their top speed efforts.

SL666 I think you are spot on the money with the GTR's at about 800hp (blacktop dyno HP assuming full factory 1800+kg weight) on that particular day. They may well have been running a much reduced tune for the day from what they are ultimately capable of however.

An N/A car puts its best foot forward right off the start line with the best of its acceleration done within the 1st 200 meters on a dragstrip. The capri had an aftermarket external overdrive fitted for this event to give the 4.11 final gearing a little beyond the 400 meter mark. Given he will have run within a whisker either way of 220kph to the 400 meter mark he then put on 37kph before the finish. A turbo car by virtue of un-natural aspiration (the best form of cheating ) runs out the back door like a bat out of hell. 600 meters for a turbo car to put on 60kph is well and truely par for the course.

Cheers,
Jason

[-GT-]

Jase, i (think i) get where you're coming from and the gist of it is that a good spread of torque makes the difference down the strip. Your point that peak power output is only part of the story is exactly why you can't compare two different cars with similar peak power. Also why drag strip comparisons aren't really relevant to top speed runs (even distance limited ones). For starters, i think we can all agree a smaller capacity big HP turbo engine might have a completely different spread of torque to a similarly powered big capacity NA/blown V8.

But the big difference from a 400m drag to a 1000m top speed run is this;

Aerodynamic drag also increases exponentially with speed.

Key point being 'exponentially'; drag has little impact compared to traction and power/torque until you get right up there, and then it's like hitting a brick wall.

Traction is the main differentiator over the 400m (once the power gets up), whereas for top speed stuff nearing 300 it's aero drag. Over 400m you spend very little time over 250km/h, and it's over about 250-270km/h that drag really gets significant. As an example, check the power and torque differences between a Macca F1 and a Veyron, then their top speed differences. Or better yet, look at what they had to do to the Veyron SS to get that extra top speed out of it.

Again, i agree with this;

I reckon 300 is big ask no matter what hp you bring to Temora, and 350 - near impossible.

Talking peak power to top speed comparisons is about as relevant as talking peak power to drag strip times; sure it's a factor, but by no means the only one.

[Yojimbo]

Hmm. So the Cooma numbers are in.

Tricky managed 265.7 kph as his best in the capri.

Some ricer with shetland ponies ran 283...

The Winning GTR ran between 259 and 264 all day. This car was basically stock with a minor turbo upgrade and a flash tune. Just the week before it ran ~10.3@136mph.

Tough conditions on the day meant most competitors agreed a 15-20 kph disadvantage due to a strong headwind.

Discuss...

[Yojimbo]

Hmm. So the Cooma numbers are in.

Tricky managed 265.7 kph as his best in the capri.

Some ricer with shetland ponies ran 283...

The Winning GTR ran between 259 and 264 all day. This car was basically stock with a minor turbo upgrade and a flash tune. Just the week before it ran ~10.3@136mph.

Tough conditions on the day meant most competitors agreed a 15-20 kph disadvantage due to a strong headwind.

Discuss...

[JustenGT8]

Top speed should take the day as the main prize.....ET is for 1/4's, not standing 1000m on a slippery runway?

283kph sounds stout for the conditions!!

[SL666]

calling kev's car "basically stock" isn't really true i was under the impression that it had 600 killer wasps + tricked out box etc - i think he went about 265 at temora, but had another hive put in when the turbo change happened between events.

There's no skill in a top speed comp - at the same power you are going to run pretty close to the same km/h

at the same power, there was 2.5 seconds between my runs.


BTW the cooma runway is uphill, and there was 30-35km/h headwinds all day - on similar power as i ran 235 previously, i ran 225.

[Yojimbo]

Based on his build thread I thought it only had the turbo / dump pipe change. Unopened motor.

[RONA]

It is only making mid 400kw at the wheels nothing stupid.

[JustenGT8]

The skill is in building the car to do it Steve

Seriously though, on an unprepped surface the AWDs just have too big an advantage in ET and virtually impossible to claw that second or so back regardless of top end. Top speed levels the playing field and encourages the drama of massive hp trying to get laid down. Why turn up with 1000hp, if you can't get off the line quickly with 600? You are just encouraging the wrong aspect of this event. I'm pretty sure the UK and Euro events are geared to reward top speed.

The clear winner on the day for me was the Supra running a whopping 20kph faster than the ET winner

[Yojimbo]

Yeah - I got its 400m data wrong too. 10.6@135.