a little ot by the way:
does anyone know how many FD`s there are in Skandinavia,? both right and lefthand drive?

 

lol

 

Why lol? just a question, since there are some people from skandinavia here maybe someone knows.

 

That video was a thing of beauty. I just about shed a tear. I can't wait to be doing highway runs again when my motor is back in.

 

anybody know what music is playing in the background?

 

Holy **** Siiiiiick

 

Thanks... very fast

 

"he probably went to the gym everyday for the last year just to be able to hold the steering wheel straight"

you can almost read a newspaper at 180 w a properly setup fd. if you have a problem at speed it is your setup.

"one of the advantages of a porshe is that the aerodynamics get better the quicker you get (or so they say) my fd just starts shaking like sh*t when i exceed about 220km/h"

this post really hacked me off... i don't think a porsche has any advantages engineeringwise over an fd. certainly NOT in aero. i have never been beaten by any porsche in 5 years at Brainerd. specifically the FD has a lower drag coefficient and less frontal area than most porsches. it also, if properly trimmed, has almost no front and rear lift.

your "so THEY say"

compares with engineering numbers... frontal area 19.26 sq ft, drag coefficient between .29 and .31 and front lift coefficient .04 and rear .01. when you get actual engineering on a porsche then we all would be interested in your conclusions. hint: no comparison.

if your car shakes at speed i strongly suggest you check the alignment, pillowball bushings, and tire balance carefully. especially the rear thrust angle. it should drive no differently at 165 than at 75.


" I had my FD to 140 MPH one time with the windows down (closed course professional driver). My suspension was bone staock and 110k on the odometer. It shook like hell and was scary. When the windows were up it felt stable"

windows up or down should make no difference. i race w the windows down. see above for high speed vibration.


"DID not see the video yet but great job, doing 300km with out help of BIG spoiler. 3 gen was not very great design on areodynamic."

boy does this comment hack me off. very wrong on BOTH comments.

FYI, the RX7 is FASTER WITH NO REAR SPOILER. the car needs no rear spoiler as it is properly trimmed longitudinally as to downforce. putting a rear spoiler on creates un-needed rear downforce AND FRONT UPFORCE. (re-read Newton's 3rd law). so the front end gets light making the car want to go airborn. in addition, there is no free lunch. downforce is accomplished at a cost. the cost is drag which costs hp. bolting on an R1 rear spoiler raises the drag coefficient and requires an additional 34 hp to run 200 mph.

as to the 3rd gen "not being very aerodynamic"

compared to WHAT? please oh please don't bring up the ricey "aero packages" sold by vendors that turn the car into a Hummer aero-wise. Mazda spent huge amounts of effort in the wind tunnel trying to SHRINK frontal area and drag. small frontal area is fast. look at nascar qualifying w taped radiator openings for less drag. do you see them with huge grilles? please do tell me what you base your assertion on as to the fd not being aero-slick.

here's someone that has it right....

"You need to fix your FD. You have problems that are probably suspension/bushing related.

I took my FD up to 162 last summer. At the time it had about 15K miles on it.

It was smooth as silk up to 130 or so. It never shaked or rattled. The only thing was, from, say 140-162, I started catching a little air, and had to correct more. I think the front end was getting light. It also might have been the road, I kept having to adjust the wheel right, because it was drifting left."

obviously a bit of high speed front lift... i would be interested if the car was running a rear spoiler, or coil-overs and air pressures... anyone of which could be a culprit.


here's another post right on the money....

"in regards to cars shaking at high speeds, i had my car at 130 a few times yesterday... absolutely smooth (it depends on the smoothness and transitions of the road you are on at that speed... id hate to hit some irregularities at high speeds)

for the person that commented about needing a big wing in the back.... if you just added a big wing in the back the front of your car would get lighter and you would be worse off. you need to address the aerodynamics of the front end first."

i have had the pleasure of racing at Brainerd Int' Raceway for 22 seasons of SCCA Nat'l racing and 5 years (recently) of tracking my fd. Brainerd is 140 miles NW of minneapolis and while off the beaten path for many is worth the haul. where else can you enter at 70 mph a 6000 ft main straight looking into a 90 degree banked wide radius turn one that you don't have to lift (much) for. i routinely run thru turn one at over 175 mph and my car doesn't brake a sweat... on Toyo Proxes street tires. no drama in turn one. turn 2 has the same 90 degree wide radius but is flat. here you do need to be right as to speed (around 115-120)or you end up in canada upside down if you make it thru the trees.... a turbo 930 porsche that i buried didn't quite get thru the trees. turn 2 is excellent for longitudial trim. executive summary: i don't run a rear spoiler and i don't need it to stick the rear end. if it is set up right the car is close to neutral without a rear spoiler that just slows you down.

as to being aerodynamic... as usual the answers to going fast are in the engineering. the formula:

rwhp= drag coefficient timesw frontal area (sq ft) times mph CUBED/ 146,600

plugging in the numbers for 188 mph........

rwhp= .31 (car was an R1 aerowise) times 19.26 sq ft frontal area times 188 cubed/146,600

rwhp= 270. add to rwhp for top speed 11% plus 60 hp for tire rotation at speed (as per carol smith Tune To Win) and you end up at 364 flywheel hp times .85 to relate to a dyno rwhp and you end up at 309 rwhp to run 188.

the fd not very areo? do the calculation on another car where you have the cd and frontal area and see what you find.

two final points:

hp needed goes up with the cube of the mph. to run 200 more than 20% more hp is required to attain a speed only 6.3% faster.

drag is very important at lower speeds because the excess of rwhp over the aero requirement determines ACCELERATION.

respect the fd engineering.

howard coleman

 

Hey Seven93 great vid man.I have 2 questions for you feel free to reply:

1.I saw that you hit 160 in 3rd and 240 in 4th.How can be possible,i hit 150 and 220 max..Also,i have 7300 rpm at 270,how much do you have at 290+?.
2.Are there any traffic control cameras inside the tunnel-how they didn't busted you after the tunnel?

 

Don't forget that you'd need that 309 RWHP in 5th gear, not 4th. If you're pulling in an overdrive gear, you're going to need even more flywheel horsepower to overcome the reduction in mechanical advantage in top gear, although it's not as bad in an FD as it is in some other cars.

The reason Corvettes top out in 5th gear and quickly slow down if you shift to 6th is because they don't have the power at the wheels to overcome air resistance at those speeds (~175-180 mph) with a 0.50:1 (C5) or 0.62:1 (Z06) 6th gear ratio. Considering that an '02+ Z06 makes an average of ~355-360 RWHP stock and has aerodynamics very similar to the FD, gearing absolutely has to be accounted for when considering top speed. In fact, the Z06 tops out at an aerodynamically-limited 174 mph according to Motor Trend (see graphic below).

Conversely, a McLaren F1 has a 0.93:1 6th gear, and even though it has a 2.37:1 differential, final drive in 6th is still 2.20:1. Compare that to 1.71:1 for the C5 and 1.92:1 for the Z06 (not to mention that the F1 has 600+ horsepower). The RX-7 has an advantage over them all, in that the 4.10:1 differential and the 0.72 5th gear combine for a final drive of 2.95:1. Coupled with excellent aerodynamics, and the FD requires less horsepower to reach very high speeds than most of the cars in its class.

BTW, the Supra Turbo 6-speed has a final drive of 2.58:1. Is it a coincidence that they also make good highway monsters?

 

yup, you are absolutely correct.

loss of torque as you head into overdrive in the trans is an important factor. that is one of 2 reasons why i run the short 5th gear which features a .832 (16.8% drop) rather than the absolutely dreadful .72 (28% drop!!!) stock fifth.

howard coleman

 

So Howard, do you run a completely stock bodied FD?

 

I'm late to the video. Great job, Crazy Dane!

I run a '99 splitter, a PFS wing, Ground-control sleeve-overs, and Koni adj. shocks. I hit 165 mph on an OK turnpike and the car felt great the entire time.

I got into the FD because of its great engineering in driveline, suspension, chassis, and aeros. Where do these fellows get the off-hand trash they believe to be "gospel"?

 

Where did you purchase this short 5th gear howard?

 

wow. . . that "flyby" was crazy. haha. . . i dont know WHAT id do if someone did that to me.

paul

 

I had the short 5th gear in my tranny, dont know where it came from but im converting it back to the stock ratio..

5th was really usable though, cant wait to see how i cruise with the .72

 

300km=187.5mph
just giving you **** nice run whats your rwhp?

 

did u have more passing power in 5th xs? willing to sell it if the condition is good?

 

More passing power than what? ive never driven a rx7 with the stock ratio cause mine had this one when i bought it. I will say that i never had any complaints about it being too low like the posts ive seen, and i had no trouble hitting 170mph.


As for reusable... it would have been before i cut it in half trying to get the hogring out of it... (also before i knew it was j-spec ratio)

Mike

 

xs..what was ur rpm in 5th gear at 80mph? stock one is at 3k rpm in 5th gear.

 

there are a couple of shorter 5th gear options.

i run fifth from an 87-88 B2600 pickup. part #R504-17-610A main 5th and #R504-17-308 for the countergear. it is nearest to 4th gear of the options...

as to my body setup.. i run an R1 splitter to minimize front lift and a 25 inch ride height at all four corners.

howard coleman

 

Howard, what is the ratio of that 5th gear set?

STEPHEN

 

howard...do u know ur rpm at 80 mph with the shorter 5th?

 

the ratios are:

b 2600 is .832
stock is .72

so if you are running at 4000 stock the b2600 would be at 4622.

shifting in to 5th w the stock ratio always gave me the feeling that life had ended. w the shorter ratio 5th gear is funtime. it is especially fun to pull modded vipers down the main staright in 5th. and i do.


howard coleman

 

i was probably closer to 4k in 5th gear at 80