my 200mph rx7 build

[DRAGON]

Interesting thread. Keep it going. We are quite embarrising top speed wise compared to the other performance models.

[turbotoaster]

thanks ross, want me to pm you on fduk or email you? as i wanted to talk to you about being involved in this

[DRAGON]

Email is easiest, I\'ll be up for helping, you have the right ideas, make sure you stick to power FC though.
I want to do 200 in my new project Midnight.
I like the mech WI idea due to simple nature of it. Not sure on your distance to the compressor wheel though.
We pulled 160 in 1/4 of a mile, and I always went way past the line due to being confused as to where it was, so not sure how fast we went in that car. Not really interested in the feeling of topspeed, to be able to say youve done it would be v cool though.

[iaint]

Few points id raise

1- safety - i assume you are going to put a roll cage in? An FD feels floaty at 145mph! I dont want to imagine how it feels anywhere remotely close to 200.

I\'ve had mine up to 171mph at Bruntingthorpe (timing beams, not gps/speedo) and while the steering felt light there was nothing floaty about it even over the undulations there.  Car has nothing significant aero-wise.

Certianly for 200mph though I\'d want to build up to it over a good few runs - I certainly wouldn\'t go for 200mph on the first run - just in case something gives way (bonnet pins etc,.).

[RobMatthews]

Would love to give this a go myself one day,do bruntingthorpe do a day for anybody to do some runs?-expensive?

As ross says its not a lot of people that can say they\'ve done it,and is a very cool club to be in!

good luck with the build,any pics yet?

[jackaleks]

Pre Turbo WI will be good so the intercooler does not need to be huge in area only good in flowing, some intercoolers are a bit too restrictive in airflow (not be confused with cooling of the air), you may find running without a restictive intercooler would be better if the WI is running well.

couldn\'t you just not bother with an intercooler and use meth with the WI? as it\'s one off runs you could pull all those tricks like sticking dry ice in the WI resevoir!

awesome project, good luck.

[turbotoaster]

Would love to give this a go myself one day,do bruntingthorpe do a day for anybody to do some runs?-expensive?

As ross says its not a lot of people that can say they\'ve done it,and is a very cool club to be in!

good luck with the build,any pics yet?

yes its called vmax, i cant remember the exact price for the day, think its about £125, type vmas into youtube, most of the cars that go are sports/supercars so its worth it just to look at the automotive porn!

the only pics i have are on this thread at the moment, saving money for all the bolt ons and will add pics as i get the parts.

couldn\'t you just not bother with an intercooler and use meth with the WI? as it\'s one off runs you could pull all those tricks like sticking dry ice in the WI resevoir!

awesome project, good luck.

Unless your running the thing on straight meth i dont think you will be able to do that and when speaking to ross hes saying we should be running 30psi+ on that turbo, the same turbo running on a stock engine at 32psi did 709whp, thats about 800fly power, now thats in the states so converting it to our power that still works out at 700fly power, if 700bhp doesnt do it, then we may aswell go jump off a bridge now!

running that sort of boost will mean the air will be pretty hot, w/i cant cover for that much, plus if that was possible, id still need to buy an intercooler after, so thats more money

[DR SCHNITZEL]

Why doesnt or hasnt someone with a 650 hp rx put the other diff on and bigger tyres and try it? if its that simple it would have been done quite a few times. If it works ill probably do the same 200 would be sweeeeeet

[mx1311]

Why doesnt or hasnt someone with a 650 hp rx put the other diff on and bigger tyres and try it? if its that simple it would have been done quite a few times. If it works ill probably do the same 200 would be sweeeeeet

quite simply because you can probably count the 650+cars in this country on one hand and most of them are geared for the qtr mile

[turbotoaster]

well from what has been said before and on fduk there is a bit of unsure-ability on what can actually be done in terms of top speed.

So today i went out with my gps meter to do some gear testing.

to do 100mph(gps) i need to do 4500rpm, give or take 20rpm

so to do 200mph i need to pull 9000rpm, simple maths. this is on 255/40/17s there maybe 1mph more for tyre expansion but ill leave that out to make it easier. also a 4.1 diff

So i got out my gear calculator program i have to put the numbers in to see how i can help.

online i have found that the 5th gear results are much longer than they should be, 0.719, which must be incorrect else id be doing a massive speed.

Anyway i adjusted my 5th gear till i got 100mph at 4500rpm with tyres stated earlier.

This gave me a 5 gear ratio of 0.820 or 22.15mph per 1000rpm.

Now according to what the guy with the stock port and same turbo as me did, his max power was at 8200rpm, because of my big streetport im calculating that my max power will probably be about 8500rpm.

So to do 200mph im going to be past my max power and its gonna be trailing off, not good really at that means ill have less power where i need it most.

At my maximum power ill only be doing 188mph, so well short of the mark, so lets change the diff to an auto one to see what we can do.

now this changes the speed at max power to 198mph, which is much better, very close to the mark.

Ill have to wait to see what my final max power/rpm will be but it least im making progress on gearing.

also say for example i only make max power at 8200rpm like the other guy did i can still hit 200mph with 8250mph if i change my rear tyres to 255/45/17

hope this clears up any potential confusion people have had in the past

[Timmy]

But if you have a wider gear ratio you have less torque you might be better off aiming to achieve max power at 9000rpm and do it with the 4.1 diff. Thats just a theory i\'m no expert.

[turbotoaster]

the engine is alread built timmy so we will just have to see what happens.

ill be running a 5inch downpipe to help with spool and running the least amount of bends in the pipeing i can but will just be down to the whether the engine can hold onto the power at high rpm.

An auto diff can be put in for the run then ill prob run a 4.1 on the road

[mx1311]

i wish you all the best sir, remember to take pictures

[turbo boy]

When is this event? What magazine is covering it?

[Ed_RX7]

AS I SAID BEFORE DUDE...WILL YOUR SEALS HOLD ON AT THAT RPM???......I THINK YOU SHOULD HAVE THE ENGINE BUILT FOR THE JOB FIRST AND FOREMOST.

ALSO EXPLAIN TO ME HOW THE SIZE OF THE DOWNPIPE WILL HELP WITH THE SPOOL....IT WILL HELP WITH OVERALL POWER BUT I DONT KNOW ABOUT SPOOL.

the engine is alread built timmy so we will just have to see what happens.

ill be running a 5inch downpipe to help with spool and running the least amount of bends in the pipeing i can but will just be down to the whether the engine can hold onto the power at high rpm.

An auto diff can be put in for the run then ill prob run a 4.1 on the road