my 200mph rx7 build

[Prof]

As part of your weight reduction regime, are you going to cull any of the liquids?
 
If only for the speed run itself, you\'ve got washer fluid for starters - a full bottle of that must be nearly a kilo.
 
From the thread - you\'ve already eliminated the PS fluid as that system\'s gone
 
Running with less fuel in the tank too ?
 
It get\'s a bit more of a toss up on reducing oil capacity / coolant capacity - as these can effect the car\'s ability to get rid of the heat - but none the less - some small weight savings maybe ?

[turbotoaster]

what tires are you going with to handle 200mph?

depends what i decide to do.

i need to sort out the rear tyres but that will depend on how the dynograph looks.

if its making power at 8500rpm then ill be running different tyres than if im making max power at 7500rpm.

if its 8500rpm ill run 285/35/18s
if its 8000rpm ill run M/T 28X12.00R18LT
if its 7500rpm ill run M/T                 30X12.00R18LT

in terms of the front tyres im not 100% sure yet, i can run my 265 semi slicks on 10in wide wheels which will give me better braking which means i can brake later.

On the other hand it also hurts me aerodynamically which maybe the difference between win and lose, so i might end up running 235 normal tyres on an 8in wide wheel. which tucks below the front arches hence i can run the front lower aswell(about 15mm) which helps against drag.

ill probably bring both sets of front wheels and compare them on the day for the best setup, same with bonnets, if the stock bonnet causes things to get to hot then ill bolt my vented one back on.

As part of your weight reduction regime, are you going to cull any of the liquids?
 
If only for the speed run itself, you\'ve got washer fluid for starters - a full bottle of that must be nearly a kilo.
 
From the thread - you\'ve already eliminated the PS fluid as that system\'s gone
 
Running with less fuel in the tank too ?
 
It get\'s a bit more of a toss up on reducing oil capacity / coolant capacity - as these can effect the car\'s ability to get rid of the heat - but none the less - some small weight savings maybe ?

to be honest weight reduction wont make a massive difference to top speed, the faster you go the less it affects it, fo example alot of top speed cars actually add ballast to help with stability.

mostly see bruntingthorpe as a place to do top speed, i look at is as a really big drag strip....700bhp isnt needed to do 200mph, you need nowhere need that sort of power, i think honestly with enough space you could hit 200mph with 550bhp, but we would need either the VW 5mile straight or nardi ring to really let the engine stretch its legs.

im doing mostly for accelaration and braking.

I look at it that the lighter you are the faster you can get to 150mph, which in theory means i can use more track in front of me to allow the car to hit 200mph and also when it comes to braking the lighter i am again the more time i have at full throttle.

in terms of liquids, rear waterwash, front waterwash will be gone. ive own the car since april 2009 and ive never used the rear water once so the entire unit will be removed including wider and motor.

looking at fuel, ill need around 5litres of fuel to do a run, but then ill want to drive back to let the engine slowly come down from the run instead of just turning it off when everything is cooking hot.

theres also the high g corner as i come onto the straight, im hoping to pull 1g of lateral grip which means that any fuel will be dragged to the left hand side of the tank so if i go to low ill end up picking up air and thats not good with as im trying to put 2bar of boost through the engine.

im thinking 4gallon of racegas should be enough to stop that, but could really do with speaking to a few of trackguys to see at what level they get fuel starvation.

Im keeping all oil and coolant in the system as i feel the larger ability to deal with heat offsets the potential 1-2kg of weight saving.

there will be a tiny bit of coolant weight saving by going to a purely oil cooled turbo, but its neglable to be fair.

the next update will be xmas so alot of it is just theory currently, unfortunately my ideas are bigger than my wallet

[Panjy]

838bhp cossie, thats nuts
 
Sounds like you\'ve given it some thought, i was worried you were making assumptions & were risking having your celebrations cut very short by running straight off the end of the runway after the big run
 
Have you had your car weighed at 1150kgs or are you estimating?
 
I\'ve been weighing everything i\'ve removed from mine (i\'m sad like that), heres some weights you might find interesting:
 
Decat - 11kg saving (standard cat is 14kgs)
PAS replacement with atomic rex manual rack - 8.5kg saving
Air con - 11.5kg saving
Air pump - 6.5kg saving
Heat shielding from underbody - 4kgs
 
I\'ve removed all the things you mentioned apart from rats nest (still on twins at mo) and spare wheel (car is an rz so has carbon seats) but don\'t have an frp bonnet or larger rad & i/c and i\'ve so far lost 75kgs.
Being an rz mines supposed to be 1270kgs standard but i\'ve not had it weighed.
Will be getting it weighed in the near future.
 
If yours was weighed at 1150kgs you\'ve just made my day as i\'ll too be able to hit 1100kgs, something i thought i wouldn\'t be able to do.
Would be nice to find out the rx7 bucked the usual trend of manufacturers claiming weights for cars that were minus any fluids :2Rolleyes

[turbotoaster]

838bhp cossie, thats nuts
 
Sounds like you\'ve given it some thought, i was worried you were making assumptions & were risking having your celebrations cut very short by running straight off the end of the runway after the big run
 
Have you had your car weighed at 1150kgs or are you estimating?
 
I\'ve been weighing everything i\'ve removed from mine (i\'m sad like that), heres some weights you might find interesting:
 
Decat - 11kg saving (standard cat is 14kgs)
PAS replacement with atomic rex manual rack - 8.5kg saving
Air con - 11.5kg saving
Air pump - 6.5kg saving
Heat shielding from underbody - 4kgs
 
I\'ve removed all the things you mentioned apart from rats nest (still on twins at mo) and spare wheel (car is an rz so has carbon seats) but don\'t have an frp bonnet or larger rad & i/c and i\'ve so far lost 75kgs.
Being an rz mines supposed to be 1270kgs standard but i\'ve not had it weighed.
Will be getting it weighed in the near future.
 
If yours was weighed at 1150kgs you\'ve just made my day as i\'ll too be able to hit 1100kgs, something i thought i wouldn\'t be able to do.
Would be nice to find out the rx7 bucked the usual trend of manufacturers claiming weights for cars that were minus any fluids :2Rolleyes

yes ive had it weighed, i used to work for an oil company who has a weigh bridge so i can weigh it any time i like.

i forgot to mention ive got rid of aircon aswell, ill also be converting to atomic rex rack, what do you think of it, any issues at slow speed?

remeber ive also weighed my car with the fuel light glued on so if you weigh yours with fuel your numbers will be different.

since when is your rz 1270kg? the stock r1 is 1250kg and you have lighter seats, i know your discs are slightly bigger but not 20kg heavier!

you could as mentioned earlier remove the rear wiper, motor and tank, most people never use them, im thinking of maybe doing that next weekend, id imagine theres a few kg there.

i think 1130kg can be achieved without having to touch the interior or changin the boot.

have you changed your battery yet, that saved me 11.4kg

[Grant Monkhouse]

glad to see the car is coming along nicely, when is the turbo arriving?
 
dont forget i have got the dataloggit stuff here if you want to map the car further. I have loaded it on to my laptop so it is ready to plug in and go. I have also got the innovate p2 sensor and software to measure afrs, im sure you can wire your afr meter onto the datalogger too.
 
Are you still on target for the 10,000 budget? as it seems like you are getting a lot of stuf for the car that will push the budget through the roof?
 
I have been looking at Atomic Rex\'s steering racks and they arent exactly cheap? Nice bit of kit though

[turbotoaster]

glad to see the car is coming along nicely, when is the turbo arriving?
 
dont forget i have got the dataloggit stuff here if you want to map the car further. I have loaded it on to my laptop so it is ready to plug in and go. I have also got the innovate p2 sensor and software to measure afrs, im sure you can wire your afr meter onto the datalogger too.
 
Are you still on target for the 10,000 budget? as it seems like you are getting a lot of stuf for the car that will push the budget through the roof?
 
I have been looking at Atomic Rex\'s steering racks and they arent exactly cheap? Nice bit of kit though

id imagine ill get the turbo and wastegate in february assuming i have no issues.

Yeh thanks for the offer, it will make my mapping much easier, ill have to let you know when i can pop over and we can do some more mapping, if you need yours mapping your more than welcome to pop down and i can do some more work to give you more power.

ive got a innovate full setup installed in the car, so we can just plug it into the datalogit.

ill still be on target on for the 10k as some of the things i am having for the car wont be used on the day hence wont be included in my budget, alot of the stuff thats on the car is because i use the car 7days a week and need to think about what im gonna do after the event, for example i want to go to the ring in the summer so ill to change things, also im changing wheels because i need more grip and my current tyres are getting low.

well i may go for an atomicrex rack but being honest ill just rip all the stock stuff out and loop the line, its free and 98% of the benefits as i cant justify the cost

[Grant Monkhouse]

id imagine ill get the turbo and wastegate in february assuming i have no issues.
 
Yeh thanks for the offer, it will make my mapping much easier, ill have to let you know when i can pop over and we can do some more mapping, if you need yours mapping your more than welcome to pop down and i can do some more work to give you more power.
 
ive got a innovate full setup installed in the car, so we can just plug it into the datalogit.
 
ill still be on target on for the 10k as some of the things i am having for the car wont be used on the day hence wont be included in my budget, alot of the stuff thats on the car is because i use the car 7days a week and need to think about what im gonna do after the event, for example i want to go to the ring in the summer so ill to change things, also im changing wheels because i need more grip and my current tyres are getting low.
 
i didnt think of it that way, so only 10,000 will be on the car for the run. makes sense as all though you are keeping to your budget there are just so many things that have to be bought fot these cars!!

[Grant Monkhouse]

just off topic but i am no longer putting the single on my FD toaster, it is going on the rx4. check out the thred in the old school section, rx4 BridgePort turbo. The car is going to be mental!!

[turbotoaster]

i didnt think of it that way, so only 10,000 will be on the car for the run. makes sense as all though you are keeping to your budget there are just so many things that have to be bought fot these cars!!

just off topic but i am no longer putting the single on my FD toaster, it is going on the rx4. check out the thred in the old school section, rx4 BridgePort turbo. The car is going to be mental!!

for example the car might not have new wheels, wont have new bumper or bonnet on the day so those add ons wont be taken into the budget.

once the car is ready to do the run ill right down what ive paid for everything to show i did it for 10k, maybe i might go over by a couple of hundred, i hope not, but im sure people would let me off if i did.

Your keeping your car to low power, taking it on tracks etc?

ill have a look at your rx4 now

[Grant Monkhouse]

well when the rx4 is running i dont think i will be as impressed with the FD on power terms so might sell it and get a normal car, or maybe not. if i get some more extra cash i may put a small single on the FD just to finish the car off and then use it for track days as i can keep the exhisting exhaust with a smaller turbo so as to meet db levels at tracks. if i do keep the car i may return the bodywork to standard and sell my veilside bodykit.
 
have been thinking about getting the original front bumper out and modifying it so it will flow more air to the fmic, could then swap it onto the car for a trck day

[turbotoaster]

well ill be honest, the veilside bodykit is pretty hideous so the quicker you can sell it the better, though you may struggle to sell the front bumper(no offence)

id just keep it on twins if your gonna track it, save your money and put it towards suspension and aerowork.

well after ive used my stock front bumper for 200mph you can have it off me if you want as ill not need it then.

[Grant Monkhouse]

i do like the bodykit as a whole on my car but the more i look at any bodykit the more i want to put it back to standard looking. very strange and a waste of money on my part but never mind.

[Panjy]

Got the 1270kg figure from info found on the net.
To be honest, nearly all the cars i\'ve ever seen weighed have come out a fair bit heavier than the manufacturers claims so i\'ll believe its 1270kgs when i get it on some corner weight scales.
That said, i saw a recent test at brunters of a nissan gtr against a veyron (evo mag did it just to show how quick the veyron was) where both were weighed upfront and they were bang on the manufacturers claims with fuel in so maybe things have changed.
 
Mine came with a smoothed rear hatch so luckily for me i didn\'t have to remove the rear wiper.
 
I have a race battery i\'m in the middle of fitting. Mine was 10.5kgs less than the full stock battery and box etc. I\'ve still got to put in 3m of heavy gauge cable, make up a fitting kit to fit it in the bins etc though so i\'m expecting the gain to be more like 8kgs.
 
I bought my atomic rex rack secondhand and at the mo its put the steering out by a mile (pulls very strongly to the left). Will get that sorted soon. Even with that issue though i\'ve got used to it very quickly. It is very hard work at car park manouvering type speeds but once you get above 20mph its fine.
Much more feel through the wheel (you feel every little bump in the road) and much more stable at speed. Tidys up the engine bay no end as well which is a bonus

[turbotoaster]

well all my weights are with the car running on fumes, that way everytime i take weight out of the car i have a \'base\' weight to go off.

id imagine 1270kg will be with alot of fuel onboard.

you should find yourself a local scrap yard, run the car down so your superlow on fuel then stick it on there, that will give you a base weight, from that any things you do to the car will be able to be seen.

i think realistically ours cars should be about the same weight now, though yours should be lighter

what did you pay for your battery setup, mine cost me £100 all in.

[Panjy]

I think the only difference weight wise with the rz was the carbon seats but you have those anyway.
The rest of the benefits of an rz were good for performance but not weight - different diff ratio, bigger front brakes, twin oil coolers (other models had those though) and bilstein shocks (not sure if they gave any weight advantage).
 
I got an odyssey extreme 25 (pc680) and terminal adaptors for £100 delivered. Still have to buy the cable, connectors, circuit breaker, bits for fitting so reckon i\'ll end up closer to £200. You win :p
 
I\'m gunna get mine corner weighted as i\'d like to get the handling as spot on as i can. A guy on sxoc (i had a 200sx before the rex) has set up his own tuning company (horsham developments) and was doing corner weighing for £30 so i\'ll get it down to him some time.