300z tt vs. sti

[alphalanos]

this is the most interesting thread i have ever seen.

[D_LinK]

I think the 300z will for sure win. Those are pretty sweet.

[TatII]

its already been stated.

drag = STi
highway = STi until around 130+mph
road racing = STi hands down
autoX = STi hands down

[nastyNater]

Originally Posted by D_LinK

I think the 300z will for sure win. Those are pretty sweet.

haha... youre on crack

[k3smostwanted]

Originally Posted by D_LinK

I think the 300z will for sure win. Those are pretty sweet.

this guy deserves a standing ovation...

[kfoote]

Originally Posted by VAD0R

I didn't mean moving the engine around as much as perhaps lowering it for the sake of better balance as in handling and perhaps permitting a more swooping hood. Even though I doubt the Z32 needs that.

Also I think there are differences between the back lip on spoiler on the 300ZXTT compared to the larger ones on the EVO and STi. The 300ZX one is more for gradual downforce while with the rally cars they design it so it imediately plants the car down. Also I think recently the spoilers for the EVO and STi seem to be really large in order to actually hamper or to prevent them from going at speeds where they could seriously go out of control. I guess theory stems from how spoilers have been getting larger since the days of group B. Anyone is welcome and I would like if somebody can correct me on this.

Btw, good point kfoote.

Thanks

The difference in wings doesn't really have to do with the speed of when the downforce is applied, it's more of an issue of efficiency. Though I don't have any concrete evidence to go from, I would guess that the STi wing produces a little less drag and a little more downforce at higher speeds than the Z does, while the wing on the Z works a lillte better at lower speeds. The airflow over the back of the car to the wing should be less turbulent than on the 300ZX than the STi, and as a result at lower speeds, the 300ZX wing will be in cleaner air and work better.

At higher speeds (in this case, think 80MPH+), what happens is that there is a layer of air that gets "stuck" to the car that gets gradually thicker both at higher speeds and the further back on the car. The net result is that the wing on the Z is close enough to the trunk that it acts more as a spoiler than a wing. This reduces downforce, but also usually reduces drag. The wing on the STi is high enough off the trunk that at higher speeds, there is probably smoother airflow off the roof, and neither of the phonomenons that the 300Z sees apply. The result is a more efficient wing, but producing more drag (and downforce) at higher speeds.

[Yaggus]

Originally Posted by k3smostwanted

BTW: im still looking for the thread that teh Z32 recently broke the fastest land speed in a certain category.

Have you tried searching for posts by the old man himself? Im pretty sure it was him who told us about it. Some people in England I think.

[k3smostwanted]

Originally Posted by kfoote

Thanks

The difference in wings doesn't really have to do with the speed of when the downforce is applied, it's more of an issue of efficiency. Though I don't have any concrete evidence to go from, I would guess that the STi wing produces a little less drag and a little more downforce at higher speeds than the Z does, while the wing on the Z works a lillte better at lower speeds. The airflow over the back of the car to the wing should be less turbulent than on the 300ZX than the STi, and as a result at lower speeds, the 300ZX wing will be in cleaner air and work better.

At higher speeds (in this case, think 80MPH+), what happens is that there is a layer of air that gets "stuck" to the car that gets gradually thicker both at higher speeds and the further back on the car. The net result is that the wing on the Z is close enough to the trunk that it acts more as a spoiler than a wing. This reduces downforce, but also usually reduces drag. The wing on the STi is high enough off the trunk that at higher speeds, there is probably smoother airflow off the roof, and neither of the phonomenons that the 300Z sees apply. The result is a more efficient wing, but producing more drag (and downforce) at higher speeds.

ok...i dont know if your totally correct on that. i do think that the wing on the STI serves more downforce than the 300zx's. no argument there...but my thoughts are as follows.

this layer of air you are talking about between the car and the air that is actually sailing over the top of the car acts as a barrier but is essentially adding to the height of your car. the moving air is pushing down on the air pocket which is pushing down on the car.

moving on, the 300zx lip spoiler acts as a scoop. it diverts the air back up which means for the air to be pushed up it has to push on the object pushing it up. this is where the downforce comes in whether this air pocket is large or small it will still serve the same purpose. have you ever played "skee-ball"? think of it like that...replace the air with the ball that you roll. when it hits that scoop it diverts it up but it pushes down on the scoop itself first.

i think the 300zx wing would actually have better performing features as velocity increases than would the STI's. at a certain point of speed the STI's wing will be more of an object to resist the air moving than it would flow with the air.

as speed increases, you want the smoothest air stream as possible but enough downforce to keep the car on the road. i think this is what the 300zx's spoiler was designed for along with the rest of the car. as you can picture the air moves smoothly across the stop of the car but pushes down on the rear to smoothly force the air back up. so the air stream curve would probably resemble an 'S'.

you have to remember that the STI was meant to slide around dirt roads it relatively high speeds, while the Z is meant to cruise at 100mph+ around wide long curves. STI needs more downforce at lower speeds to help keep it from sliding off the track while the Z just needs enough downforce at very high speeds to keep it from taking flight.

Originally Posted by Yaggus

Have you tried searching for posts by the old man himself? Im pretty sure it was him who told us about it. Some people in England I think.

yeah im getting ready to do some searching...i just havent had time to look for it.

[k3smostwanted]

ahhh...found it. the following is the link to the post...

http://www.automotiveforums.com/vbul...03&postcount=9

here is the key information for you lazy ones.

Posted: Wed Oct 20, 2004 2:30 am Post subject: '94 twin turbo set a new world record at Bonneville Reply with quote
Carlson Racing sponcered by RaVer Motorsports set a new world record at last week's world finals held by SCTA and BNI on the Bonneville Salt Flats. The car ran in F, Blown Grand Touring (3.0 liter max, two seater, no body mods allowed for aerodynamics, turbocharged on gas, partial interior required). The car is owned by Greg Carlson and was driven by his son Kenny Carlson. The previous record was set by "Dandy" K. Tanaka (I believe he is the owner of the Japanese magazine Options ; he’s a great and humble guy who I had the honor to meet at this year's Speedweek last August). Tanaka's record was set 14 years ago at 222+mph. We reset it to 224+mph, and I see LOTS of potential for next year.

[kfoote]

Originally Posted by k3smostwanted

ok...i dont know if your totally correct on that. i do think that the wing on the STI serves more downforce than the 300zx's. no argument there...but my thoughts are as follows.

this layer of air you are talking about between the car and the air that is actually sailing over the top of the car acts as a barrier but is essentially adding to the height of your car. the moving air is pushing down on the air pocket which is pushing down on the car.

Correct, but the boundary layer is thick enough at the back of the car to smooth out the bumps, and my be thick enough to significantly slow the air speed over the lip spoiler. Though it's not as pronounced, the STi has one as well. Calculating how thick it is franlky would require a car and more time than I am willing to put into it at this point, but a basic overview of the physics can be seen at
http://www.grc.nasa.gov/WWW/K-12/airplane/boundlay.html

moving on, the 300zx lip spoiler acts as a scoop. it diverts the air back up which means for the air to be pushed up it has to push on the object pushing it up. this is where the downforce comes in whether this air pocket is large or small it will still serve the same purpose. have you ever played "skee-ball"? think of it like that...replace the air with the ball that you roll. when it hits that scoop it diverts it up but it pushes down on the scoop itself first.

Agreed, but what the boundary layer phonomenon does in your skee ball example is effectively raises the floor, reduces the angle of the ramp, and shortens the length of the angled part of the ramp, all of which contribute to the ball not going as high even as ball speed is increased. The higher the ball goes, the more downforce there is.

i think the 300zx wing would actually have better performing features as velocity increases than would the STI's. at a certain point of speed the STI's wing will be more of an object to resist the air moving than it would flow with the air.

As far as efficiency goes (downforce/drag), I agree, and the higher the speed of the car, the greater the advantage for the 300ZX would become. Both downforce and drag will be higher for the STi, and simply because of how the mathematics of these systems work, the drag increases more rapidly than the downforce does, thus making the 300ZX more efficient.

as speed increases, you want the smoothest air stream as possible but enough downforce to keep the car on the road. i think this is what the 300zx's spoiler was designed for along with the rest of the car. as you can picture the air moves smoothly across the stop of the car but pushes down on the rear to smoothly force the air back up. so the air stream curve would probably resemble an 'S'.

If you're going for top speed, yes. If you're going for maximum cornering ability at high speed, then usually the higher downforce, even with the higher drag, will be better over the course of a lap on a road course.

you have to remember that the STI was meant to slide around dirt roads it relatively high speeds, while the Z is meant to cruise at 100mph+ around wide long curves. STI needs more downforce at lower speeds to help keep it from sliding off the track while the Z just needs enough downforce at very high speeds to keep it from taking flight.

Cornering at lower speeds (say, under 80 MPH in either of these cars), is a lot more closely related to mechanical grip than aerodynamic grip. Realistically, taking the wing totally off the STi will have no effect on cornering speeds below 50 MPH, as withthe design of the rest of the car, it has inherent corner entry and mid corner understeer, meaning lack of front grip. Adding more rear grip will only make that situation worse.

[sossy]

of course this thread favors the 300z so why not take it to an sti forum and then duke it out. both cars are amazing in their own way so you will never know which is better until you get em neck and neck!

[GForce957]

Originally Posted by sossy

of course this thread favors the 300z so why not take it to an sti forum and then duke it out. both cars are amazing in their own way so you will never know which is better until you get em neck and neck!

this thread favors 300z? how? and if you take it to an sti forum that will just make it very one sided.

[nastyNater]

Originally Posted by alphalanos

this is the most interesting thread i have ever seen.

[k3smostwanted]

Originally Posted by kfoote

Correct, but the boundary layer is thick enough at the back of the car to smooth out the bumps, and my be thick enough to significantly slow the air speed over the lip spoiler. Though it's not as pronounced, the STi has one as well. Calculating how thick it is franlky would require a car and more time than I am willing to put into it at this point, but a basic overview of the physics can be seen at
http://www.grc.nasa.gov/WWW/K-12/airplane/boundlay.html

Agreed, but what the boundary layer phonomenon does in your skee ball example is effectively raises the floor, reduces the angle of the ramp, and shortens the length of the angled part of the ramp, all of which contribute to the ball not going as high even as ball speed is increased. The higher the ball goes, the more downforce there is.

As far as efficiency goes (downforce/drag), I agree, and the higher the speed of the car, the greater the advantage for the 300ZX would become. Both downforce and drag will be higher for the STi, and simply because of how the mathematics of these systems work, the drag increases more rapidly than the downforce does, thus making the 300ZX more efficient.

If you're going for top speed, yes. If you're going for maximum cornering ability at high speed, then usually the higher downforce, even with the higher drag, will be better over the course of a lap on a road course.

Cornering at lower speeds (say, under 80 MPH in either of these cars), is a lot more closely related to mechanical grip than aerodynamic grip. Realistically, taking the wing totally off the STi will have no effect on cornering speeds below 50 MPH, as withthe design of the rest of the car, it has inherent corner entry and mid corner understeer, meaning lack of front grip. Adding more rear grip will only make that situation worse.

i think in the long run....we are basically totally agreeing with each other but we have differents views of whats better thus making us favor one or the other car.

the STI's car is made for what the rest of the car is made for...rallying.

the 300zx's wing is made for what the rest of the car is made for...Grand Touring.

both have ups both have down but the bottom line is both were made to fit the rest of the car.