my 200mph rx7 build

[shaunwil]

You may be surprised just how accurate it is. The cpu output reading of speed is much more accurate if you have the right rolling radius.

Shaun

[turbotoaster]

ah cool, to be fair i tried it at low speed for a few secs then took it off, ill have to have a drive down the dual carriage way with my gps on and see how accurate it is.

aubec, at what boost did you get 293bhp anyway, im guessing you ran out of fuel?

[Aubec]

ah cool, to be fair i tried it at low speed for a few secs then took it off, ill have to have a drive down the dual carriage way with my gps on and see how accurate it is.

aubec, at what boost did you get 293bhp anyway, im guessing you ran out of fuel?

0.8 or thereabouts - it spikes a bit.  Injector duty in the mid eighties on boost - reckon the injectors probably came with the car, so could probably have mapped a bit higher if I\'d had them cleaned / replaced.

Fuelling / power\'s not my priority at the moment - cooling is!  I\'ll probably go to 1680 secondaries and an FPR in the summer and try for another 40 or so horses or go single and aim for 400.

[turbotoaster]

ah cool, was just wondering to compare as i put 283 on a basemap(super rich) with stock downpipe and cat on 0.7bar.

Im guessing your waiting for a koyo rad, how much did that cost you?

[Aubec]

On basemap I was pulling only about 250ish, which is why I think my injectors are probably at the end of their useful life.

£248 for the N-flow model (1443N), plus whatever customs whack on that.  As soon as it arrives I\'ll update with the price I paid all in.  The track and trace says it\'s sitting with customs at the moment.

My PFC reads the boost about 0.1 higher than WGT\'s own boost gauge did while they were mapping.  Needs work, but I\'m not pushing it any harder until I\'ve got cooling then fuelling sorted.  I hit silly temps on the last two corners of the \'Ring in September (>120deg) and am not going to risk my engine going boom for the sake of 20 horses.

[Rod]

i think any weight reduction wont hurt at the end of the day but since ill already be carrying alot of speed onto the main straight it will be less of a factor

Weight makes no difference 50metres gained at the start is only .5 sec longer on the throttle at 200+mph. Trying to take the bend at high speed is not the way too do it either, getting straight quickly is the correct way & a quick car will be faster from a standing start, but harder on the clutch, which is the only reason to use the bend, all proven many times.
 
 
Note slow speed entry & using all the road.
 
http://www.youtube.com/watch?v=8hXNzf2kjqc

[DR SCHNITZEL]

Weight makes no difference 50metres gained at the start is only .5 sec longer on the throttle at 200+mph. Trying to take the bend at high speed is not the way too do it either, getting straight quickly is the correct way & a quick car will be faster from a standing start, but harder on the clutch, which is the only reason to use the bend, all proven many times.
 
 
Note slow speed entry & using all the road.
 
http://www.youtube.com/watch?v=8hXNzf2kjqc

Surely weight will effect terminal speed, of course it will.:Hammer

[Aubec]

Weight makes no difference 50metres gained at the start is only .5 sec longer on the throttle at 200+mph.

But could also be the difference between stopping on the runway and running off onto the grass :driving

[turbotoaster]

Weight makes no difference 50metres gained at the start is only .5 sec longer on the throttle at 200+mph. Trying to take the bend at high speed is not the way too do it either, getting straight quickly is the correct way & a quick car will be faster from a standing start, but harder on the clutch, which is the only reason to use the bend, all proven many times.
 
 
Note slow speed entry & using all the road.
 
http://www.youtube.com/watch?v=8hXNzf2kjqc

ive been watching that a few times before rod to try and learn the perfect line to take onto the straight, i was actually gonna copy the same lines as that hoping its the best.

Weight will help but like i say, only a very tiny amount

[HaywardRotary]

Think about gear ratios and diff ratios.
9000rpm in 5th gear on a stock 4.1 diff ratio is 210mph.
You need taller diff ratio really so that your grunt is in lower rpm rev band.
When racing beat did 243mph with their 3 rotor 3 turbo 900hp car they had such tall gearing that the car needed a push to get it up to a speed so that it could drive.
In the Option speed challenge in NZ some years back a Scoot RX7 did 203.5mph and they used 5 engines that weekend to do it! Each engine was a side port and small PP.
Here is link to the vid http://www.youtube.com/watch?v=Gqd3l6P3PV4&feature=PlayList&p=2178662A35E970DA&playnext=1&playnext_from=PL&index=50
Regards
Carl

[rx jamie]

excellent thread mate. seems like youve put a hell of a lot of thought into the build.

personally id go for a gt45 or gt47 turbo as you will not need all your power low down for a top speed run. id have probably went for a larger port aswell such as a bridge, again to move the power further up the rev range and give a few more revs. could always dump a bit of nitrous on top in 5th aswell just to see you onwards to 200 :Laugh.    

oh and carl check your emails will ya, i sent you an email today, cant ring you as im at work today.

[turbotoaster]

Think about gear ratios and diff ratios.
9000rpm in 5th gear on a stock 4.1 diff ratio is 210mph.
You need taller diff ratio really so that your grunt is in lower rpm rev band.
When racing beat did 243mph with their 3 rotor 3 turbo 900hp car they had such tall gearing that the car needed a push to get it up to a speed so that it could drive.
In the Option speed challenge in NZ some years back a Scoot RX7 did 203.5mph and they used 5 engines that weekend to do it! Each engine was a side port and small PP.
Here is link to the vid http://www.youtube.com/watch?v=Gqd3l6P3PV4&feature=PlayList&p=2178662A35E970DA&playnext=1&playnext_from=PL&index=50
Regards
Carl

 
If you look back carl ive already got this covered, with in gear testing on a gps to make sure its setup correctly.
 
At 200mph the speedo will read 210mph...it needs 9020rpm to do 200mph on 255/40/17 with a 4.1diff, dont follow your speedo or those gear calculaters.
 
Racing Beats car was actually geared for 300mph as that was there aim but due to conditions at the event they were limited to 243mph. Since mazda pulled rx7s from sale in USA in 1995 they never had the financial backing to go back and try again
 
The problem with the scoot car was that when running a t51r spl on such a modified engine it ran out of power to early in the revs, it made maximum power(680bhp) at 1.6bar at 7100rpm yet the car revved to 9800rpm(which means the car wont be making 680bhp that high) so they really should have either lengthened the ratios(since they ran stock ratios) or gone for a bigger turbo.
 
Also there car was running alot more downforce than mine will because of stability on the B road/wangan which is much different environment.
 
Trying to do it from a rolling start down a tight bumpy B road is alot harder than a wide open flat airfield, if you look at Rods video of his cosworth, hes already up to high 180s before hes a third of the way down the field.

excellent thread mate. seems like youve put a hell of a lot of thought into the build.
 
personally id go for a gt45 or gt47 turbo as you will not need all your power low down for a top speed run. id have probably went for a larger port aswell such as a bridge, again to move the power further up the rev range and give a few more revs. could always dump a bit of nitrous on top in 5th aswell just to see you onwards to 200 :Laugh.
 
oh and carl check your emails will ya, i sent you an email today, cant ring you as im at work today.

Well the engine was already built before i decided to do this challenge as my original aim for the car was only 500bhp on pump fuel weekend car.
 
I believe theres no point in going over on the turbo as it will come on boost so late that it will drop out of boost threshold between gears because im limited on revs to below 9k.
 
I think the turbo im going for meets all my goals, is cheap and spools well enough to make it a decent turbo for a 550bhp pump fuel street car after.
 
Nitrous has been mentioned to me enough but i think its gonna be enough fun trying to map the car for 700-750bhp without adding that into the situation, if this was a piston engine then id defo have it, but rotarys arnt the strongest when a tune isnt 100% and i dont want to make to many variables or make it to complicated for my mapper

[turbotoaster]

my oils arrived today.

Love that i worked for silkolene, free oils, would have cost me £320 if i needed to buy all that!!



thats fully syn 15w50 oil
gearbox and diff oil

[L18M]

Bonus

[Nik da Greek]

.....nab us 4 litres of Pro 4, would you mate? The bike could do with an oil change :Giggle