Car Test 2000 uses vehicle ride height, coefficient of drag, frontal area, coefficient of friction for the tires, tire diameter, gearing, and the engine's power curve to determine the drag-limited top speed.

It can't? It generated 231.78 mph for a McLaren F1 and 178.36 for a Z06... close enough.

 

Jim, notice that nowhere in there does CT2K ask for a weight variable? I got into a rather heated discussion regarding the top speed of snowmobiles ( coming from NY, i used to snowmobile ALOT) on a frozen lake and a bunch of monkeys tried to tell me that a snowmobile with a 100lb person would have a higher top speed than a snowmobile with a 200lb person, even though they could go for an infinite distance. I laughed so hard i fell off the bar stool. Then i got back up and told them otherwise......

Darril

 

Ok, I dont understand this statement. How does a 6 speed give you better cruising ability? The only way it could give you better cruising ability is if you run a real high ratio so your rpms are real low....which is similar to a Vette. That type of 6th gear is pointless, just like a Vette if you make 6th to low so its good for cruising then you hit top speed in 5th anyway. As for falling below 4500 in 5th.......maybe if you go into 5th WAYYY to early. 5th doesnt fall down to 4500 if you redline 4th....which you would if you were racing.

The only thing 6th would be good for is if you gear it to max at 200 so you can run a lower 5th but that gets back to my point of just changing the stock 5th gear for pennies on the dollar. Sure your max is going to be 175 instead of 200 but so what? Is anyway really going to go 200 in a street FD? Personally I dont think the car will make it to 200 without something falling apart.

Why would someone pay $7K for a trans so they can say they have enough gear to hit 200mph??? YOU CAN SAY THAT NOW WITH THE STOCKER!!!!

Lets get to the real heart of the matter, just admit it you know you guys just want a 6th cause it sounds better. You can make up all kind of excuses to justify spending 7K on a 6 speed. I think some of you guys just want one cause it sounds cool haha, it makes you feel bad when people say "Whats that thing got? A 6 speed?" and you have to say "nah, its just a 5speed"

STEPHEN

 

"While most amplifiers go to 10, ours go to 11."

 

haha, nice quote Jim That's pretty impressive about CT2K also...even though the McLaren F1's top speed is actually 241mph, close enough I suppose Btw, I also love your 240mph speedo! I suppose you converted a JDM km/h speedo?

In regards to the cruising ability of a 6speed: the stock gearbox goes 178mph with the tall 5th gear, with the shorter ratio I'm sure it's less. Couldn't you just keep the same ratios on gears 1-5 as the 5 speed with upgraded 5th and then have 6 even lower? Wouldn't that result in much upgraded cruising ability and much much higher top speed? I really don't know much about tranny's, having never done any research in that area of the FD, but I don't understand how having 1 extra gear wouldn't make for a higher top speed, and thus a lower cruising rpm at a given speed. Feel free to explain!

 

"...round an' round we go, where it stops, nobody knows..."

 

Road & Track measured 231 mph in the F1 they tested, driven by Mario Andretti. It's my understanding that the McLaren that got to 240.1 wasn't a production car. It was the XP5, or Experimental Prototype 5...

Nope, I sent my instrument cluster off to have a new face printed to match the original font and then the speedometer was recalibrated to 8,000 ppm @ 60 mph (stock is 8,202) to make adapting it to the T56 VSS output easier. The tachometer was then recalibrated to 1/2 to match the V8 signal.

 

I to your perfectionism!

 

You mean my obsessive-compulsive disorder?

BTW, CT2K estimated 234.74 mph @ 6,353 rpm in 6th gear. I dug up the spreadsheet I created when I was running different simulations prior to chosing my final gear ratios.

 

LOL! I was just talking about this at lunch today. Out of the 4 people at lunch no-one knew what I was talking about.

 

Hmmmm. So which is it steven? Does the stocker do 200 or 175??
If you can afford it, do you really need to ask?
While the idea of owning a 6 speed gearbox is enticing, the real "heart of the matter" is that it's:
-stronger than the stock FD gearset
-eliminates 5th gear syncro problems
-provides MUCH better fine tuning ability for your final drive ratio.
Think about it for a second. I don't pretend to know just how many rear ends there are for the FD. I think there are the 3.73, 4.11 and what? A 4.32 or something like that? I'm sure i've missed a couple or am totally out to lunch on that last one, but the point is that with the extra cog, you can fine tune your final drive ratio a little bit better for what you want to do (i.e. drag, road race, street, etc).

The fact of the matter is we can sit here and debate 5 spd vs. 6 spd all day with virtually no evidence to back up any of our claims however i'm moved by REAL world evidence and testing. Moneys a little tight at the moment, but i fully intend to put a 6 speed gearset in my FD and test it both in the quartermile, race from a roll and cruising.

Darril

p.s. Oh yeah, and it sounds cool to say "i have a 6 speed FD"

 

Heh....wish I could say that "money's a little tight at the moment" relative to plunking down around $5K to get a single turbo setup, then dialed in to run correctly, then an additional $7K for a six-speed gearbox....

Good luck, mon....

 

Whats so confusing??? You can do 201mph with the stock gearing.....HOWEVER you can change out the 5th gear and do around 175.

Why is that so confusing?

And yea, you can change out the final drive gear and gain some acceleration, BUT it hurts your top end. My entire point from the start was that the stock trans has great gearing except for 5th but you can change it out for less than 1/10 the price of a upgraded trans. For the original poster this is a huge benifit as he was wanting to race Supras from a kick on the highway. The 6th gear can help you go from 175-200+ or get better fuel economy. Well, I dont see the point in spending 7K to go over 175 in a street car unless you just want to look cool and its definatly not economical to spend $7K to save money on gas.

Yes, you can get customs gears and they might help you a small amount, but they are not worth $7K cause there will always be something else you can spend that money on that will help more.

The only car it would be worth the money in is a pure race car. Now if someone just has $7k to blow and doesnt care then whatever, they can do it cause its "cool" to have a 6 speed.

BTW - I can afford it but I still have to ask cause I dont like to throw my money away. Just cause someone can afford to waste thier money doesnt mean they should.

STEPHEN

 

Stock gearing 201mph hummm OK hehe

 

The gear-limited top speed at 8,000 rpm with the stock P225/50-16s and stock gearing is ~201 mph. Of course that doesn't take into account wind resistance and other factors.

A = 225mm (tread width)
B = .50 (aspect ratio)
C = 16" (wheel diameter)

Tire height = ((2 * (A * B)) / 25.4) + C = 24.86"
Tire circumference = (2 * 3.14159 * (24.86" / 2)) = 78.09"

A = 8,000 rpm
B = 0.719 (5th gear ratio)
C = 4.10 (differential ratio)
D = 78.09" (P225/50-16 tire circumference, nominal)
E = 60 min. (1 hour)
F = 63,360" (1 mile)

Gear-limited top speed = (((A / B / C) * D) * E) / F = 200.68 mph

For P275/40-17s, substitute 80.62" for D above. Gear-limited top speed is bumped up to ~207 mph, so it's possible you might be able to break 200 mph with the stock gearing, given enough power... not likely, but possible.

 

Anyone ever got there FD to 200? hehe

Anyway BUY THE KIT DAMN IT!!!!!!!!!!! I want to see how you like it and see what you think of it.

 

I thought redline was 7500? That's cerntainly where the red lines are

 

my car sucks

 

If you want to blow 7K on a 6 speed, go right ahead and enjoy doing that!

I have the 0.806:1 5th in my trans (cost about 250 dollars) and it ROCKS. There is no feeling of a "drop" when I shift into it.

Think of my setup as a 6 speed without 6th gear and you have got the idea. Sure, I might be "limited" to around 180 mph, but I think that's plenty fast for street driving!

Brian

 

This have been raised up countless times, and I have known this set over 5 yrs. And have seriously considered getting one, but it is just too darn expensive. I am not looking for the speed limit it allows me, but the close ratio is what appeal to me. As I like to do solo 2 n lapping.
Here are the ratio:
1st 2.823
2nd 1.941
3rd 1.513
4th 1.200
5th 0.958
6th 0.780
Final drive 4.100