Hi i have a standerd type RSR at 280bhp.What speed gain do you get by increasing to about 450-500bhp.Top speed and 0-60 thanks.
You dont increase the speed, only the ability to get to 70mph quicker. :D
To increase the speed, you need to change both the diff and/or gearbox ratio\'s.
Fish
And by changing the diff ratio, you change the rate at which you can accelerate again (by slowing it down). You\'d have to get a longer fifth gear...or 6 gears into the \'box!
I suppose, depending upon aerodynamics, and gear ratios, 450-500bhp is good for nearly 200mph.
So providing you have enough HP (and a long enought stretch of track) what top end would you hope to see from a standard gearbox and diff???
Well stock 0-60 for a Type R with 280 bhp is 4.9 I think... so with 450-500 bhp it must be amazingly quick... just taking a guess I would say 0-60 definately in the low 4\'s or even late or mid 3\'s... can anyone confirm?
Quote from: kash_5Well stock 0-60 for a Type R with 280 bhp is 4.9 I think... so with 450-500 bhp it must be amazingly quick... just taking a guess I would say 0-60 definately in the low 4\'s or even late or mid 3\'s... can anyone confirm?
Only problem would be traction though :2eek
If my calculations are correct, at 8000rpm, a fifth gear ration of 0.71, and final drive of 4.1, then the speed would be 197.59mph.
Calculations may be incorrect though, but i think they\'re right! Obviously, you\'d need the power to get to that speed though! And a long enough straight!
Pretty sure top theoretical speed of the standard manual FD is something like 176.
Mine topped out at a real 153mph (timing beams) at Bruntingthorp (indicated 165+ on speedo). That\'s with 293rwhp but very high intake temps. On a cooler day I\'d have expected 160.
500bhp might just be enough in the 1.5 miles of brunters (starting at around 60 mph round the bottom bend) to see 190. The few cars that top 200 are pushing out well over 600 bhp (RUF Pork for example) although that may be fly wheel...
Read somewhere that above something like 120, is really where the power is needed, as wind resistance becomes a major factor.
As with Iains time, mine recorded 152 at Bruntingthorpe (just over 160 on the clock), from a standing start - but it was me that wimped out - the end of the straight was looming a bit too quick! Thats with a 4.3:1 final ratio and std set up (~230-240 at the hubs (so presumably less at the wheels?)).
By the way, I though the RS-R in std form was 265hp; didn\'t the 280 engines make an appearance in the 99on updates? Not that it makes too much difference!
Well, obviously only theoretical, but my calculations are as follows:
Engine doing 8000rpm.
Fifth gear ratio of 0.71
Therefore propshaft is doing 11267.6rpm
Diff ratio of 4.1
Therefore wheel rpm is doing 2748.2rpm
Now, this is where i may be going wrong a bit. Wheel diameter, including inflated tyre is 61.03cm
Therefore, circumferance is 191.7319cm
That works out as 5269.1761 metres per minutes (rpm of wheels times circumferance)
Therefore, a speed of 316.15kph = 197.59mph
Maybe i got it wrong somewhere. Pretty sure the only place i went wrong was with the wheel diameter though.
Quote from: davyvHi i have a standerd type RSR at 280bhp.What speed gain do you get by increasing to about 450-500bhp.Top speed and 0-60 thanks.
Are you the lucky guy to have bought \'Flat Steves\' car, if so then well done, as stated in earlier posts the RSR is 265stock but with the 4.3 diff :) I managed a 4.5 ish to \'60 running 420atw [496fw] and Traction was a BIG problem, so much so I had to purchase cut slicks to minamise wheel spin, think you will find unless you change your gearing top speed will not alter that much ........... just how quickly you get there :Giggle
QuoteI managed a 4.5 ish to \'60 running 420atw [496fw] and Traction was a BIG problem, so much so I had to purchase cut slicks to minamise wheel spin
John, what time did you manage after the slicks were put on?
Quote from: kash_5John, what time did you manage after the slicks were put on?
Not been tested .......... yet :burnout
Certainly considerably quicker, mind you it is alot harder on the ol back axle, I recon it is at least 1.5secs quicker to 100, when we were at Brunters I was spinning up in 1st, 2nd , 3rd and 4th :2Mad not long after the clutch started slipping as well, not anymore though :wave
Had my spedo reading just over the 170 mark, but unless you have calibrated timing gear, you can\'t take that as an exact speed (exciting tho) :Giggle went up to 150 no probs then took longer to ease it\'s way up through 160 and 170. Thats where the higher horsepower will make a difference. I\'m only at 320bhp at the fly.
Mark
If you want higher top speed you could always fit the diff from an Auto - isnt that 3.9??
Ive had 175 indicated at 3am, bone stock, private road, very very low temps outside (like bitterly cold)
thats indicated though, and 80mph on the clock is 75 on road angel, so id hate to think how inaccurate the speedo is high up. Once the cars run in ill let you know my GPS speed :P
check this link out http://rx7.com/store/rx7/fddrivetrain_rearend.html scroll to bottom of page for table.
If you are doing 7,500rpm in 5th that equates to 182mph (remember on standard rims/tyres) so speed will be higher with bigger wheels. :burnout
Mine is fairly accurate to about 100 mph, only around 2mph out.
When the speedo says 180, the gps says 165.
QuoteIf you are doing 7,500rpm in 5th that equates to 182mph (remember on standard rims/tyres) so speed will be higher with bigger wheels.
That basically agrees with my calculation
yep, spot on mate.
So if i can get 5th gear to max out at 9,000 rpm, then theoretically i\'ll be breaking the 200mph barrier!! :evillaugh :evillaugh :evillaugh
My speedo says 90mph when im actually doing 70mph...its a bit broken... :) must get my stolen road angel replaced soon so i know what speed im actually doing.. :rolleyes:
Quotemust get my stolen road angel replaced soon so i know what speed im actually doing..
What would be the fun in that :driving