my 200mph rx7 build

[lee mills]

To be honest i really hope you achieve what you want to, The only thing which really interests me is whether you can do it for this budget and without any form of sponsorship. Please keep us informed as this is an intriging thread

[turbotoaster]

boooo you should have a go, what power are you putting out now?

i did a few calcs from other cars etc.

a stock port fd running a bw 475 turbo made 500hp at 17psi at 8200, now from what ive seen on steve ports the max power is raised about 400-500rpm, im not thinking it will make that much difference but probably say 300rpm at this level so say making maximum power at 8500rpm.

That means ill rev it to around 9k depending on how the power drops off and where the rpm drops to on upshift.

from what i remember, 100mph is around 4500 in 5th on gps on a 4.1 diff with 255/40/17 tyres, so in theory 9k is 200mph, im not saying im going to do it on a 4.1 diff, but changing to a 3.9 should bring it down nicely as it adds on 10mph at top speed and then theres tyre changes that can for example at another 7mph


the plan is once ive done it to show all my costs to prove it can be done, things like fuel, oil and stuff i wont put in, but all the bolt ons etc.

Ill give you a rough price guide now so you can see

[turbotoaster]

car £3000
tein suspension £300
rebuild £3000, includes porting, new bearings, belts, housings, ast delete etc
manifold, turbo, wastegate, screamer pipe, exhaust, inc oil lines £1500
radiator £120
intercooler £260
power fc around £400-450
injectors £140
fuel rail, fpr £200
custom dual fuel pump setup £200
homemade w/i kit £200
that takes me up to £9370 at the moment, some things might be cheaper, some things might be dearer, but thats what im working to at the moment

[S3TH]

Most of the 500bhp lads have been through a fair bit to achieve what they have, IIRC even Lee\'s engine threw a tip and RX motors rebuilt it on warranty.

Unless Steve\'s prepared to warranty your engine knowing your intentions, if you throw a tip... the budget will be thrown too... be extremely careful!

[Prof]

Surely larger tyres will give you a percentage not just 7 mph - in theory if you go with a higher profile and larger tyre / wheel size, you could get quite a bit of a speed gain, at the expense of a little acceleraton.
 
Still - good project - wish you well with it. :cheers

[turbotoaster]

i just did it based on travelling at 215mph what i would gain by upping my tyre size.

i know it will be less as the mph goes down but thought that wouldnt be relevant for this thread.

What your thoughts prof, any words of wisdom for this a level physics student!

[lee mills]

The only thing i would suggest for safety is a roll cage. You would be mad to try and top 200mph without one in my opinion. Safety first:cheers

[ad4m1]

few more bbits to consider:
 
clutch to take 600hp (£500)
Mapping (£250)
Twin power (£150)
Spark Plugs (£100)
Auto diff with front flange change offset against manual diff sale (£100)
 
if ur revving to 9k, are you gonna do anything with the bearings and stationary gears?

[turbotoaster]

mapping is being taken care of i think because of magazine coverage.

spark plugs and twin power i forgot to add thanks
we shall see how the exedy clutch holds out but that will be something ill need to look into again ill bet.

Well theres a guy running on a stock mazda engine now at 700bhp reving to 9k for 6months now run 9s at the strip so we shall see how it goes, its running all new mazda bearings at the moment, some people say clearancing is advisable over 9k as you risk getting a side seal stuck, but theres a few reving that high and are fine

not fussed about a rollcage, i know you think im mental but im going in a straight line, i take more risk cornering at 150mph down my local A500

[Ed_RX7]

cheers bud... i found all the stuff i had. cheers anyway

http://www.partsexpressonline.com/cart/products/TO4E-T%252d76%7B47%7D%22Q%22-Trim.html#

that link should work ed, and give you all the info you need

jaydee...well the car has done 800mile up to yet and seems ok, yes i know thats hardly any mileage but good news so far, the pics of the port arnt the ones of the actual engine, just ones he used for reference, he rotated the engine by hand and marked out the movements of the seals and then ported to them, cant remember the figure exactly but something like another 2mm and the seal would fall out, ill have to direct him to the thread.

the manifolds have been increased insize, not a massive amount i dont think, i never saw the engine in bits, just the pics he sent me as hes nearly 300miles away from me, havent really had any issues with no butterflies at the moment, but i stay below 3k for the moment anyway as the engine isnt fully run in yet and im still on stock ecu

[Prof]

i just did it based on travelling at 215mph what i would gain by upping my tyre size.
 
i know it will be less as the mph goes down but thought that wouldnt be relevant for this thread.
 
What your thoughts prof, any words of wisdom for this a level physics student!

Just thinking - tyres - there aren\'t that many brands out there that could safely take this sort of speed - tis a lot !
 
Also, having just watched a top gear rerun recently - featuring the veyron - you might consider an adjustable areofoil.  You want downforce for grip and acceleration at mid speeds, but at the top end it will start to interfere with your end goal - so some way of changing attack angle?
 
From your water diagram - looks like your thinking of spraying pre turbo - jury is still out on that as a good or bad idea - but I\'ve always thought it might result in an increase in the water droplet size as they compressor forces atomised water droplets together.
 
You might find WI isnt needed at all with alcohol type fuels - Steve and Kev were getting incredible cooling from their PP engines running E85 - would mean you could get rid of the intercooler potentially and have a smoother front end for the car ?
 
Anyway - these are just the ramblings of a senile old man !
 
I\'d be interested to see your WI idea in piccies though - ingenious. :cool

[turbotoaster]

alot of people, about 5 that i can think of have told me to go e85, the problem is they just dont sell it up here, its great as its a slow burning fuel and you can run some proper boost. with race fuel i can just stick it in the tank and map it without the need to massive injectors, i cant remember the exact amount but you need 20-30% more fuel, i suppose i could run 2 550c and 4 1600s but then its cost on rails etc and im not sure if i can do it in budget.

toyo currently sponsor madrod whos saph cossie has done 206.1mph and is trying for 215mph this year and they are just giving him sets of 888s

from what the guys say in america and oz the turbo actually helps with atomisation, thats why they run alot more water pre turbo than post turbo but you need to get the distance between the jet and the turbo spot on, it should be aiming directly at the turbo wheel and be around 4inches away.

they also run ALOT of water, the guy with a 700bhp on pump fuel throws in 1600cc/min of straight water, he does have an awesome ignition system though.

his ignition setup cost nearly £600 though and im not sure yet whether i can fit it in my budget.

on a twinpower you can throw about 600cc/min of water in and your ok

[m1tch]

the car will be going to bruntingthorpe, the power is based on coefficient of worse cars than the rx7 to be honest, that and a little bit of input from a 650bhp porsche that did 211mph in the same distance ive got(2miles)

there are no plans for aero work, though i may remove the rear spoiler as it adds no downforce and only drag, ill also remove the windscreen wipers and mirrors, thats it

people are forgetting about changes in tire sizes aswell, your saying it cant be done, funny how a 670bhp 4x4 escort cosworth did it, and a 650bhp 4x4 corolla aswell, ive already dont a gps 156mph and felt fine, i know 200mph is different but im doing in a straight line on a ride runway, cant get anymore safer.

i spoke to the guys at racing beat, he lost control because he spun the rear tyres at 220mph, salt is different than tarmac

I don\'t actually know why they actually race on salt, as its only a thin crust of salt, the rest is unstable mud lol I know when they ran the boniville FC there were regulations on the hight of the spoiler, which wasn\'t enough. I would definatly run a rear spoiler, not a run of the mill bolt on one, but a proper one that has been aero tested.

[mx1311]

Few points id raise


3- power. I would say you arent going to do it with 650 either. 650 is just enough theoretically to overcome aerodynamic drag. Rolling resistance will be pretty high come 200mph. If it were me, id be running some sort of tall rear wing to keep the back end down and thats going to increase aerodynamic drag greatly due to its shape and i imagine an increase in drag induced by the negative lift around it

600hp will be ample to do it on a 2mile straight but good luck getting your fd to a reliable 600hp and keeping it together on a top speed run!

a tall rear wing (bgw) will knock off around 20mph on your top speed at the measured mile, i know this because i have done it

Finally youve set yourself a target of doing this on a 2 mile straight. If youre lucky you might be doing 140 at the half way mark.

with 600fwhp he should be doing that just past the 1/4mile, again, i know

its harder than you think getting to 200, good luck and keep us posted

fyi, willday logged 177 in 4th gear at a km but had to back off the measured mile due to the car becoming unstable, i could tell you his ratios but id have to kill you

[SiH]

I\'m still converned about aero tbh - I\'d not just talking about the CoD - I\'m talking the whole package.
You need to look at making the car as slippery as possible, but you do still need downforce. At the least, I\'d look at creating a flat underbody and using some sort of diffuser to keep the back stable. It\'s about so much more than just running the car as low as possible.

Top speed runs put a massive strain on cars - I\'d genuinely be surprised (And very pleasantly so) if you managed to do it in budget.
Your price list is optimistic to say the least in my opinion, and this is from a man who\'s jsut doing a \'basic\' rebuild, and realising the extra costs. It\'s the small things like fuel lines, gaskets, etc that really start to add up.

If you can do it, it would be a massive acheivement - I say go for it. It would also be a massive kick in the teeth for all the eBay parts haters (as I guess from the prices this is the sort of thing you are going to run with a lot of the parts - IC, rad etc)