speed limiter

rxboy · Post by **rxboy** » Mon Feb 02, 2004 12:52 pm

Some interesting reading from a document I found:

1st Gear 2nd Gear 3rd Gear 4th Gear 5th Gear
2k rpm 10mph 17mph 24mph 32mph 40mph
3k rpm 14mph 25mph 36mph 48mph 60mph
4k rpm 19mph 33mph 48mph 64mph 80mph
5k rpm 22mph 42mph 60mph 80mph 100mph
6k rpm 27mph 50mph 71mph 96mph 120mph
7k rpm 32mph 59mph 79mph 112mph 140mph
8k rpm 36mph 67mph 88mph 128mph 160mph

The actual observed readings in 5th gear end at 4k rpm (ie 80 mph). Beyond that is pure mathematics.

dannyboyau · Post by **dannyboyau** » Mon Feb 02, 2004 1:23 pm

read all my posts

what is the coefficent of drag for the FTO?

you seem quick to use this in your calculations yet i have never seen it mentioned anywhere, and would love to know what it is.

gear ratios may come into actually determining speeds, but at no stage have i mentioned gear ratio i have been talking about 5th gear and top speed and what revs it was doing in 5th gear at the maximum speed i could do with no speed limiter

if you read my posts properly, you will see i never claimed 300, as i pointed out my speedo does not read that high so i had to do a rough calculation using revs = speed at 3000 rpm in 5th. i mearly pointed out that according to my maths that figures to be 300.

My barbed responses are because it pisses me off when someone does not read the posts properly then comments on them and in the process implys i am lying

Get some glasses

go back and read them you will see twice i have said my FTO pre conversion did it, It was a nakaya tune model with a few mods, so it was faster than a normal GPX from the start oh and when it come to drag there are more than one factor you should be taking into account when doing these calculations.

I.E. type of road, type of tyre, wind speed and direction, wieght ect.

Oh and for the record where i did it did have a very slight downhill run, road was only a few months old and it was in the early hours of the morning with an easterly wind blowing which was a tail wind, anyone from Perth or in Perth will know this might be a slight assistance.

how about answering the questions i have asked you

another question what is the coefficent of drag for the FTO and what do you believe to be the top speed that it is capable off according to your calculations.

ruchi · Post by **ruchi** » Mon Feb 02, 2004 2:24 pm

Post by **Supplanter** » Mon Feb 02, 2004 2:37 pm

ALRIGHT YOU TWO, TIME OUT!

Sheesh you are acting like twelve year olds in a school playground... any more and I will have to get the principal. Just agree to disagree... I know a marriage councilor, let me know if you want her number

jonowong · Post by **jonowong** » Mon Feb 02, 2004 4:46 pm

lol did anyone bother to read all that except them 2?

GPXXX · Post by **GPXXX** » Mon Feb 02, 2004 5:04 pm

Supplanter wrote:ALRIGHT YOU TWO, TIME OUT!

Sheesh you are acting like twelve year olds in a school playground... any more and I will have to get the principal.

....uh, did somebody call me?

and yes Jono, i read every single alphabets there are in this thread... as informative as it is technical, please try not to take it personal ok champs?

let's just put it this way - whether or not our cars can do 290kph or 250kph in NA or turbo form, it's not worth losing sleep over it because let's face it - owning an FTO is not all about top speed, agreed?

hey Robb, does that beer and women in the pub offer still stand??

dannyboyau · Post by **dannyboyau** » Mon Feb 02, 2004 6:11 pm

The actual cd will depend upon the bodykit and spoiler you have, as well as factors such as ride height. In general FTOs would probably range from around .30 to .36, so lets average it out at around 0.33

so you dont know what it is and you are guessing

so there for you cant be certain abouy your calculation as they are a guess

i understand gear ratios and it is the diff ratio that you need to concern your self with most, but then again an expert like you already knows that

Does anyone else know of any other non-turbo FTO that can generate in excess of 300HP, and what mods are required?

this comment is interesting as your not even sure about the drag so how can you calculate the Hp required to get to 292 kmh can I have a look at your crystal ball, I want to know how you figured it out

G_A_V · Post by **G_A_V** » Mon Feb 02, 2004 6:34 pm

one thing you might need to consider ruchi also is that the bulk of the fto power is above 4k so while most cars would be revving from 4-6k, the fto revs from 4-9k, which makes it a lot easier for the car to pick up speed especially considering that the fto is hitting bulk power and torque, where other cars power would dip before 5k

Theremin · Post by **Theremin** » Mon Feb 02, 2004 7:02 pm

Theoretical top speed can be worked out fairly easily (I think).

This site has details of FTO gear ratios.
http://www.redfto.co.uk/FTO%20Specs.html

Using a 5sp manual GPX:
- 5th gear ratio is 0.82
- final gear ratio is 4.312

So, at 9000 engine rpm, the wheels should be doing 9000/0.82/4.312 = 2545.36 rpm. Ok? (BTW, I thought the rev limited cut in before 9000 rpm?)

I'm not sure how big the tyre of a FTO is, but I'll assume a diameter of 58cm (which is about 17" for the rims + 2x3" for the tyre). (Can someone run out and put a tape measure on their tyre to check this!) The circumference (58 cm x pi) = 182 cm.

If the wheels are turning at 2545.36 rpm, then for every minute your tyres will cover a distance of 463,561 cm. Divide by 100,000 to convert to kms and multiple by 60 to convert to hours = 278 km/h.

You could only exceed this by
- using a larger diameter tyre than 58cm
- changing the gear ratios
- going beyond 9000 rpm

Of course friction and drag mean this is a theortical top speed and if those factors increase enough to outweigh engine output then the car would reach its terminal velocity (a bit like how something dropped from a height won't accellerate indefinitely?)

I hope I have got this right! Been a long time since I did any maths. Let me know if I've stuffed it up.

Theremin · Post by **Theremin** » Mon Feb 02, 2004 7:19 pm

Actually I just found another website which tells me that the diameter of a 205/50R16 tyre (stock for GPX) is 61.14cm. Running that through the equation gives a top speed of 293km/h.

dannyboyau · Post by **dannyboyau** » Mon Feb 02, 2004 7:22 pm

I'm not sure how big the tyre of a FTO is, but I'll assume a diameter of 58cm (which is about 17" for the rims + 2x3" for the tyre). (Can someone run out and put a tape measure on their tyre to check this!) The circumference (58 cm x pi) = 182 cm.

circumference of my tyres 191 cm just measured it using a piece of string then i messured the string, i did it three times to triple check

dannyboyau · Post by **dannyboyau** » Mon Feb 02, 2004 7:26 pm

I'm not sure how big the tyre of a FTO is, but I'll assume a diameter of 58cm (which is about 17" for the rims + 2x3" for the tyre). (Can someone run out and put a tape measure on their tyre to check this!) The circumference (58 cm x pi) = 182 cm.

circumference of my tyres 191 cm just measured it using a piece of string then i messured the string, i did it three times to triple check

FTO338 · Post by **FTO338** » Mon Feb 02, 2004 9:05 pm

Supplanter wrote: I know a marriage councilor, let me know if you want her number

Is she pretty? hahahahah if she is, send her number this way yeahh

ruchi · Post by **ruchi** » Mon Feb 02, 2004 9:26 pm

GPXXX · Post by **GPXXX** » Mon Feb 02, 2004 11:19 pm

for what it's worth, and solely for the purpose of lightening up the mood around here, my 320hp NA FTO on Gran Turismo 3 does 280kph on the high speed run test (stock gearbox)... I know it's only a game, but it's also meant to be a realistic driving simulator so that is perhaps the closest indication I have for my own enjoyment at the moment...

enough technicalities aside, who's up for a roadtrip to Darwin and put these theories to test??

ruchi · Post by **ruchi** » Mon Feb 02, 2004 11:34 pm

dannyboyau · Post by **dannyboyau** » Tue Feb 03, 2004 12:21 am

well if i still had the same motor i would get a video recorder and go and tape it being done.

dannyboyau wrote:
i understand gear ratios and it is the diff ratio that you need to concern your self with most, but then again an expert like you already knows that
The three main things are the gear ratio, the final drive ratio and the rolling circumference of the wheels. These items directly link the speed to the revs. The three factors (revs, speed, and gear ratios) are all linked, if you mention two (as you did) the third is there by default, as it makes up the rest of the equation.

this is all good and well theroretically but anyone who has done any modifications to cars will tell you it is the diff ratio that you change to help change your top speed or to help improve your quater mile time. the gear ratios are what they are and unless you are going to spend a hell of a lot of money to change them, it dosent really mater, it is what you have to live with, when is it going to get through to you that the differant gear ratios dont mater, it is only the final ratio of 5th gear that maters when it comes to top speed

do your calculations then for what you think the FTO should be doing at 200 Hp at the flywheel.

I would like to know

i think a lot of people out there would probably agree that the eclipse would have a similar c/d to the FTO actually the c/d for the FTO would probably be a little bit better considering the shape of the rear end and that the fto wieghs about 200 Kgs less

Can you show us the calculations or did you just do a web search and pick something you thought might be close.

dannyboyau · Post by **dannyboyau** » Tue Feb 03, 2004 12:48 am

also did you know that the electric FTO built by mitsubishi had a c/d of 0.22

Post by **smorison** » Tue Feb 03, 2004 1:13 am

Ruchi,
i don't like to actively moderate the forums as i believe we are all grown up sensible individuals. However in this case your actions are those of someone deliberately trying to stir up trouble.

Would you be so kind as to keep your comments on this thread on topic and not of a nature that could be deemed as offensive.

thank you for your co-operation.

ruchi · Post by **ruchi** » Tue Feb 03, 2004 1:24 am