TonyBurns

iTrader: (3)

They changed all the Hawkeye's gearing so they ran 60 in 2nd, you have to note that the 2.5's only run to 7k rpm where as the JDM 2ltrs still run to over 8k so if you put a UK 6 speed gearbox into a JDM then it will have longer gearing.

Tony

Adam-M

Do the JDM Hawks have longer gearing or do they have the same gearing as all the other 6 speeds but still manage 60 in 2nd gear due to the 8250rpm?

Would love a long ratio'd 6 speed box in a classic, the shorter ratio was a bit of a pain.

Fat Boy

not necessarily - it's the wind resistance as well. Wind resistance increases as a square of the speed so you need ever increasing increases in power for each step up in very high speed. Most cars below the really big power cars could drive down an autobahn for 30 miles and never get to pull top revs in top gear due to that.

Fat Boy

?? You are actually agreeing with my point - speedos read optimistically so don't believe them as a true indication of speed. It makes no difference what your speedo reads up to.

I very much doubt you'd get it to display 180 but even so it wouldn't be anywhere near 180 in reality.

Below is a P1 speedo and when the GPS was displaying/ my car was actually doing 163.47mph on a mile and a half runway, the needle on my speedo was pointing straight down - way past the 160mph mark on the speedo (and probably way past where 180mph would be too)

dazdavies

iTrader: (22)

I managed 170mph in mine which was a GPS reading my speedometer was showing 180mph at the time.

I have 600bhp i'm fairly confident I could crack 190mph(gps) but 200 is a very tall order indeed. The physical force of the air you're having to shift at that speed is phenominal.

Fat Boy

I know where you're coming from as the JDM 6 speed is poor for drag due to number of gear changes plus is slightly higher revs for motorway cruising, but it is perfect imho for track/ b roads imho. I've never needed higher than 155ish even at Silverstone. I don't see the point in worrying about top end unless you're thinking about lowering cruising revs for economy/noise or you are running big power and you want to do Vmax runs for a competition or whatever.

Andy F, who did 210mph on GPS and regularly ran 150mph 1/4 miles in his old car, has said many times how he hates Vmax runs as you are just sitting there waiting for something catastrophic to happen.


E.g. have alook at this - this was at the 30-130 runway day that we've been talking about- this evo driver took his rear spoiler off to try to go a tiny bit faster and the mere act of lifting off at Vmax in a straight line caused him to spin multiple times (and to buy new undercrackers probably)

http://www.google.co.uk/url?url=http...KO2HIg&cad=rja



AdamM - I'm pretty sure Skullfudge/Clive didn't get to 197mph at Marham 30-130- more 180 odd from memory and he was running 560bhp.

scooby red

iTrader: (2)

If you can hook it up without destroying clutch whats a 0-60 figure when running bout 320ish bhp? low to mid 4's ?

chopperman

Well a standard RB320 was 4.8 secs. A standard newage sti was about 5.1 secs.

Osimabu

iTrader: (2)

During Isle of Man TT course lap that Mark Higgins did last June, he reached either 149 or 151 mph on Sulby Straight (where the top superbikes are touching 190+). That's usually the fastest part of the TT course.

There was talk of his car having a top speed of around 160mph but he apparently didn't hit that anywhere. He was driving a mildly tuned car on closed roads, which gives a pretty good idea of how fast the cars are in the (almost) real world.

There's a DVD out of the lap if anyone's interested incidentally (cheaper on Amazon though):

http://www.dukevideo.com/Isle-of-Man...ecord-DVD.aspx

Fat Boy

That's it exactly, Daz.

I could probably get to 170mph GPS in mine with 450bhp and you could probably get to 190mph GPS in yours with 600bhp- that 20 mph higher top end takes 150BHP extra.

The next 10mph is probably another 150bhp or so again.

rb5 286

iTrader: (2)

only time i have ever gone off the clock was in my RB5 which was full decat HKS, K&N cone with PPP ECU, dial went round to top speed but then the revs kept going up and up

IIRC the sat nav read 171mph

It had about another 1k rpm before limiter but I shat myself and backed off - it was still pulling like a train

all my 2.5ltr PPP scoobs have never been over 150 - When I get asked whats the top speed I just say no idea because a) its true and b) I dont care lol!!!!

I really dont see the point of what the top end of it is,

rb5 286

iTrader: (2)

also depends on your scooby shape and the aero pack you have, i.e. low or no bootspoiler = lot less drag and more top end capabilities

dunx

iTrader: (3)

Mine came limited to 256 kph or around 155 mph. ( 2002 STI Type UK )

dunx

Markyscoob

What amazes me is how any of you can get to these top speeds with your bonnets staying on- both of the Scoobies I've had have tried to rip their bonnets off at above 120ish (Legal on IOM :-) )

I'm going to get some flush pins for mine as looking down and seeing th corners up about an inch and the scoop wobbling about is quite disconcerting.

Remember also that total drag is a combination of CDi, cross sectional area and the square of the speed. My Hawkeye STi overreads by 5mph at all points on the speedo compared to GPS, but is consistent. Not sure how I can correct that.

If you want to go faster, take the top spoiler blade off, fit a splitter and drop the car as low as possible and fold or remove the mirrors and wipers. On a Blob STi you would want a WRX scoop as well to minimise drag.

I would leave the wing in place for stability as you get a lot of rear lift at speed. The Roof vane adds to downforce but that causes drag. Perhaps the WRX wing might be a better option for top speed runs?

Bonner flush fit pins wil stop it lifting as that causes a LOT of drag. The front of the bonnet is a very low pressure area and you get a lot of lift there, hence the pull. Holding down the bonnet and taping all the edges with clear tape would also help.

P.S. I is a pilot so have done a bit on aerodynamics.

To visualise. Air flows under the car and over and around the sides. A sharper edge to the sides helps to stop cross winds creating smooth flow around which is the pull you get in crosswind.

Pressure is lowest where the air is fastest, i.e. under the front bumper/floor tray, above the front of the bonnet, at the top front of the roof.

Pressure is highest at slow points, such as the back of the bonnet bottom of windscreen and at the rear base of the back screen.

Really low pressure is caused by turbulence and eddies at the rear under the boot lid and around the back bumper. Hence all the road **** sucked up. the Rear diffuser of the Hawek STi helps to speed up flow under the cart and fill the gap with underfloor air not side/top air.

Rear Spoilers/wings.

A Spoiler is just that. It breaks up airflow. the lower element of the STi wing is a spoiler. any bolt on lip that protrudes from the boot is a spoiler because it is designed to kill the flow of air at the back which causes lift. It generates a lot of drag as it causes turbulence.

A wing like the top element of the Sti device or better still the Prodrive rear wing is so because air can flow above AND below, these are inherently more efficient as they produce negative lift without too much turbulence.

If I was going for top speed runs I would choose the Prodrive rear wing. Then the WRX standard wing and lastly the STi wing.

My first choice would be bonnet pins though!!!!

Ciaran

iTrader: (16)

Used to have 169mph saved in the sat nav. Circa 400BHP classic. Doubt it would do anymore and I also wouldn't try it again. Car starts to get a bit unstable anything over about 140

rb5 286

iTrader: (2)

especially with the bonnet being ally, not much weight to hold it down!!!
the hawk, hatch and 2011 saloon have extremely good aeros underneath

I always beleive that the force of air into the bonnet scoop would stop the bonnet lifting lol

Osimabu

iTrader: (2)

Imprezas are mostly based on rally cars where acceleration is the main objective and top speed irrelevant. And the works cars are restricted to 300bhp or so too.

I think it's acceleration that I love and I'm happy to admit to being pretty scared of high speeds. My old 1991 Honda CBR600FM was a fair bit faster on acceleration up to 70 (officer...) than my Scoob, and you could buy one of those today for less than a new set of discs and pads all round for the car. But old age means I'm much happier in a car than on a bike these days.

Markyscoob, as Spock would no doubt put it: "Fascinating". Thanks for such detailed information.

As a thought on GPS, does it take into account going up and down hills, where the road forms the hypotenuse of a triangle, so you're actually travelling further than the satellite thinks you are between any two points?

Fat Boy

Daz and mine are both classic shapes with similar real spoilers and front splitters.

Adam-M

Thanks for the info mate, its not top speed im bothered about with the longer 6th speed as to be honest i wouldn't be suprised if the 5th and 6th gear where just the same, it's more the 1st 2nd and 3rd i'd love to be longer. Its a pain in the **** sitting behind a car on a straight in 3rd gear, pull out to overtake and just as I get one car length its time for a change. Its all right if you change gear like a luney a suppose . One advantage of a close ratio box like you say its in the powerband immediately which is great on a b-road/track.

No straight roads about my way anyway mate, even the motorways lol, thats Scotland for you, just twisty back roads.

Total Impreza must be incorrect then lol, it doesn't suprise atall tbh.

Adam