I was racing the RX7 at santa pod last saturday, was running about 13.5 but it was hot conditions etc so reckon theres room for improvement. anyhow the PFC is set for 7500rpm for the limiter, when I was near on crossing the line on the 1/4 mile I was needing to change into 4th, so I upped the revs to 8k and it was a little better, also got my best time of the day doing that... although I was still about 50yds off the line when I hit the limiter in 3rd, so was hoping next tiem I run I want to pass the line in 3rd gear saving some time. is this possible on the rotary? what rev limit would you recommend or at least suggest I avoided, would 8500rpm asking for trouble? the car still pulls strongly at 8k too so thats not a worry running out of puff... it pulls better than me grinding it into 4th gear anyhow ;)
Thanks, Dave
hmmm you should be able to do over a tone in 3rd gear.... what mods you running with... if you are aiming for the 12 second run then depending on the mods/ engine porting and other factors air temp being one of them, a 3rd gear run should be possible. I know you can easily get to 140 in fourth....
Quote from: the lemsterI know you can easily get to 140 in fourth....
The speedo\'s not hugely accurate, add in the km-to-mph converter and it\'s really a lottery. 153 mph (timing beam verified) was close to 170 mph on the speedo on mine last sunday...
I\'d guess 140 is really closer to 130 but still rapid though!
yeah I was reading about 110 on the speedo in 3rd but the trap speed was 99 and 102 on the 4 runs that I did.... funnily enough my fastest run was at 99mph
Quote from: davegttph1Iwould 8500rpm asking for trouble? the car still pulls strongly at 8k too so thats not a worry running out of puff... it pulls better than me grinding it into 4th gear anyhow ;)
Thanks, Dave
depends if you\'ve got enough duty cycle left. There\'s no way I could get up that far without running out of fuel. I run to 8100 and that is really pushing it.
my 140 in fourth was with only about 6k rpm so there is room for a lot more to go...
and the fastest time with 99 is probably due to hitting the gears right and getting a good start......
was thinking about this earlier and we see dyno graphs giving a maxh power or 342 hp at 5700 rpm... so wouldnt it be a good idea to change up gear when you would hit this rev area when chged.... ie changed into fourth and the revs are at 5700 which would give you max hp?.... daft question... or not?
sorry for thread hijack.....
technically yes you\'d be better of changing gear but unless you have an instantanious tiptronic gearbox or a perfect shifter of the gears then no, the longer gears you have the better chance of pulling off a good time from my experience on the strip
Quote from: the lemstermy 140 in fourth was with only about 6k rpm so there is room for a lot more to go...
and the fastest time with 99 is probably due to hitting the gears right and getting a good start......
was thinking about this earlier and we see dyno graphs giving a maxh power or 342 hp at 5700 rpm... so wouldnt it be a good idea to change up gear when you would hit this rev area when chged.... ie changed into fourth and the revs are at 5700 which would give you max hp?.... daft question... or not?
sorry for thread hijack.....
depends really. Power tends to just keep going up, its torque that peaks around 6k (I\'m fairly sure anyhow).
The question is, do you get more oomph between say 6k and 8k in second or 3k and 5k in 3rd.
If the former then leave your gear change until later, if the latter, change up at 6k.
Dependant on the state of tune will determine your rev limit with HUGE ports you wont see peak power @ 8k :flamed , the 3rd / 4th gear question can be resolved by running different tyre sizes :bandit or a different dif ratio. The best times achieved with FD\'s over the 1/4 have sub 1.7 60\' times hth
my 60ft time was 2.077 which I thought was reasonable.... running about 325bhp PFC, full zaust, blitz filters and 0.9bar off boost
Launching a rex is an art in itself..........wish I could master it :p I have come to the conclusion it is all about riding the clutch, I\'ve tried hard b#lls out 7k launches, 2.5k and bogged and just about everything in between still cant get below 2.3 - 60\'. Hoping me new super sticky tyres will overcome the constant wheelspin and if I can master feeding the clutch then, who knows, still it is great fun trying to get it right.
Should be seeing sub 12sec still not broken 13\'s yet...oh well just have to keep trying.
LOL only had the rex about 1 month and did a 2.1 60ft time on my first run... ;) :D I did about 2k revs and floored it when the lights went green. found it the best way, tried to ride the clutch, tried to ease off the line but couldnt get quicker than just foot to the floor and go for it...lol
thats on 18\'s too
Only trouble with changing up too soon after peak power is you might be a bit laggy in the next gear ie. too big a rev drop. I tried this at RSII after going on the dyno and coming to same conclusion as you, changed into 4th at 6000ish and it didnt feel as quick as a 8000 rev change up. Possibly somewhere in between....7000ish? will try out next time :)
I think i had 106mph out of 3rd gear @ 7200rpm, but you wanna shift approx 7500rpm anyways i believe as power starts to drop off closer to 8000rpm.
My limiter is set @ 8000rpm on the power FC.
Quote from: gsb876I think i had 106mph out of 3rd gear @ 7200rpm, but you wanna shift approx 7500rpm anyways i believe as power starts to drop off closer to 8000rpm.
Dependant on the state of tune...........some of us have porting and peak power is @8k+ :cool and rev limiter set somewhat higher :eek
Quote from: John YorkeQuote from: gsb876I think i had 106mph out of 3rd gear @ 7200rpm, but you wanna shift approx 7500rpm anyways i believe as power starts to drop off closer to 8000rpm.
Dependant on the state of tune...........some of us have porting and peak power is @8k+ :cool and rev limiter set somewhat higher :eek
Very true John, although with Dave quoting 13.5secs as best so far 8000rpm is gonna be too high for his state of tune, but ok for your setup,
Cheers