my 200mph rx7 build

[turbotoaster]

OK, well ive decided to copy my project thread so liam and anyone else can have a read, been meaning to do this for a few weeks but never got around to it, im hoping for as much advise as you guys can give me and hopefully this will be alot of fun.

Right lets start at the beginning, after looking around for ages to get myself my next car i get myself a budget of 3-4k for something.

My criteria was that it would have to able to take a good thrashing and i didnt have to watch the rear view mirror for smoke everytime i put my foot down(5yrs of running a 12sec r5 turbo)


so i was left with an evo 4, and rx7, 200sx and a r32 gtr.

After thinking, well how fast do i want to go and at what point with would i be happy i had enough power i sat down and thought, well my 5 was 325bhp/ton and i want to go faster than that so im looking at 450bhp evo/200sx, that will cost a fortune and will only match my old car.

I then did some more research on the gtr, at 4k im looking at the very bottom end of the market and id again need 470-480bhp to match it, skyline tax is pretty bad and id need at least injectors, turbos etc to get that.

So finally i looked around and after watching many a youtube video and also alot of initial d i realised the best handling and cheapest car for big power was the rx7.

So basically lived on beans and noodles to try and set myself a decent timescale to get the money together, i then started to look at cars.

Eventually i found one in derby, pics look good and was decently priced at 3k
(pic below)


when going to see the car i marvelled of how good condition it was, not a spot of rot, with it coming into the uk in 2006 and only done 55k it was worth it, i knew the clutch was on its way out, but compared to 6k for some of the others id seen i thought it was a bargain.

Well a few weeks later it developed a water leak, because of the undertray and the cramped engine bay i couldnt work it out where it was coming from, since it only did it after driving for about 10mins i took the guess that it was coming from the overflow on the AST, so i blocked the overflow and took it for a very steady drive for 5mins, looked underneath and no water, thinking i had cracked it, i headed home and pulled outside only to be greeted with an bang under the bonnet

(im sure you can guess what happened)

The plastic AST exploded! So im stuck with a problem, OK, ill just bridge the between the 2 hoses using a hollowed out pen as it seems to fit the bill and people on the forums say they run without an AST anyway.

So drove it around for a few days, everything seemed fine, even had a couple of 160mph top speed runs...seems people on the forums were correct

Anyway came to my car one morning only to see it surrounded by water, popped the bonnet to see my main waterpipe to the top of the radiator has exploded during the night, ribbed it literally in 2 and i find its my main water hose that was leaking that caused the leak but because the water ran to almost the other side of the engine bay before dripping onto the floor it made it hard to work out it was from there.

A call to WGT to see if he can get one for me, he says he will get one ordered, we after waiting a few days and getting panicky as its my daily driver for work i ring him again to see whats happening, after some research mazda have told him that part is not currently being made anymore, the company mazda used to have make them has gone bump so thats it.

A search of ebay i find a guy selling them blue silicone ones for £29.99 for the set and he only lives 10mins from my house, beats £50 for rubber ones from mazda!

After fitting them i dashed up to WGT to get a metal AST to save the same issue happening again.

Well after a few months i decided i wanted more power so installed a set of second hand HKS filter kit i got cheap(£70) from carl at harward.

Then a month later i fitted a xspower cooler(£120) with the idea that id build some ducting in the future after fdash\'s decent results with his so the engine bay looks like this.


A few weeks after i decided the clutch really needed to be sorted, i could drive the car but as soon as i put my foot down it would slip madly.

Talking to pip again we discussed clutches and i went for a stage one uprated exedy clutch thats rated for 340ft/lb which i thought should be enough to keep me going for a while.

While i was in for a clutch i got the chance to watch and film this monster being mapped


Well from this point i was pretty happy with the car, drove really well and was alot of fun, though there was no camber at the front and would understeer at the limit so i decided suspension would be my next port of call.

After asking a fellow fduk member(mattie) about his suspension he offered me his set, only been used in the dry and hardly done any miles, pretty much like new for £300


so after fitting them and messing with the dampering and ride height i noticed alot more grip on the front end by gaining camber, first test was the local roundabout that i used to understeer around, well a big second gear sideways moment definetly told me the front end gripped better!

Looks alot better aswell



So this brings me up to the more present time.

NOW THIS IS WHERE IT GETS INTERESTING


My water seals had been going for quite along time, so i just kept topping the water up but it finally got to the point of no return so i was left with a non-running rex, luckily i knew this would happen eventually so i had been saving for quite a long time in the event id need to get my wallet out.

Now im sure you have been browsing ebay and seen the advert for the rx7 rebuild guy, well i decided to give him a ring and see what he had to say.

Now what can i say about this guy, most companies ive ever called in the past cant get you off the phone quick enough but steve rivett was completely the opposite, if you call him you best have a good 1hr of your life free to talk.

We spoke about everything rotary from the simple stuff to everything complex, never have i met a guy so passionate about what he does, or infact so honest. He told me about the first 2 engines he built that didnt even last 500miles because of mistakes he made while he was learning, that spoke to me about how open he was, i would never imagine any other tuner tell you about there ....ups! He is a retired engineer and only started this because his son is a racecar driver and owns a rx7 trackcar.

So after a long chat i decided to take my car down there, upon arriving im surrounded by other rx7s that hes working on, he borrows a garage from a friend in return for looking after his rx7(also owns a f355 and f40!), this was all very grass routes stuff and i like the personal touch he gives.

Anyway, we begin talking about what he will be doing to the car and what i want from the car.

This is the point where we sit down and have a good think, realistically how much power do i truely want, what level will i need to be at that ill never want anymore, i come to the conclusion that 500bhp should be enough.

So he shows me this tools and we talk about porting, he owns a set of racing beat large street port templates and shows me a current engine he is in the middle of porting. We look at rjpartri dyno graph to see what he has done in the past.

this is on twins with 0.8bar of boost, as you can see its making good power up at 8k, if was even making decent power at 8.5k and from what ive read that means that the ports are quite large and are flowing well.

So since he has never built an engine that he knows is going for 500bhp we talk some more about the porting, using the templates to start him off, once he has done that he is going to push the porting a bit more than normal for maximum flow, also hes going to port my UIM, LIM and remove the secondary throttle.

Finally when building it back up he will fit a sump brace and fast reacting air temp sensor to help out in future mapping.

This now brings me onto where i have changed my goals for the project as you can see before i didnt really have a direction for the car.

I have decided to take the top speed record for an rx7 in europe, not just take it, but also break the 200mph mark, now this isnt down the autobahn where thats gonna be alot easier, this will be in england at bruntingthorpe.

After speaking to stav at redline he is willing to feature the car and take me to brunters.

Ill tell you about my plans in the next post, just need to save this one for the moment


      
                                                                                    

[turbotoaster]

The biggest thing about this build and the reason for the magazine interest is the budget, my goal is to hit 200mph for £10,000 including buying the car, which is something thats never been heard of before and that stav is a massive fan of.

ive been chatting to a guy on the ford forums called MADRod, he is pretty much the expert on everything top speed as he has had many attempts down brunters and his figures are always spot on when hes helping people.

He thinks i can do it with about 620bhp-650bhp as long as my powergraphs match my gear ratios, obviously if im making max power lower down the revs then ill need to change my diff.

so this brings me onto how im going to make the power

[clive]

Good Luck with your project as I sure that not only our UK MRC members will be very interested in this along with myself but also our many visitors from all around the world,

To give you a Jap car bench mark to beat, Adrian Smith with his FenSport Celica upped his previous record of 205 MPH in his old Corrolla to 207 MPH just before Christmas

Keep us posted as I sure the slippery shap of the FD can better this just like Racing Beat did with their 242 MPH run at Bonneville

[lee mills]

As much as i admire your enthusiasm and dont doubt that the speed you plan to reach is acheavable my only niggling doubt is wether you would be able to achieve this for £10000 or under.
The only way i can see this happening is if you manage to beg steal or borrow the parts that are required.
 
Hopefully you will prove me wrong and achieve your goals

[turbotoaster]

now to make the power i want ill need a rather large turbo, since this has such a strict budget there will be no t51r or all singing and dancing rollerbearing turbo.

For this i had to spend alot of time looking at compressor maps, searching forums all over the world for ideas(not just rotary)

I finally came up with my turbo of choice, its a masterpower t76 turbo, the compressor wheel is the same size as a t51r spl/gt4202 which is rated for 1000bhp(or 750bhp rotary) but has a smaller turbine wheel which brings it down to 850bhp rated turbo(same as a t51 kai)

Now the kai does 550bhp at only 1.2bar of boost and on race gas and water injection ill be running around 1.6-1.7bar which should fall nicely into my 640bhp im aiming for.

this turbo will be coming from USA for $800 and is journel based with a divided 1.00 rear A/R





next thing to cover is the manifold, it will be roughly based in design on the HKS stainless steel one but the turbo will be slightly further forward in the engine bay so that the comp housing doesnt hit the strut top as the housing is much bigger than the t51s

This is going to be designed by a guy of passionford, hes done loads of turbo civic ones and they seem well made, plus hes not a tuner so no massive bill there, made in shed ftw!!


this is the design to get your heads around it as im not the best at explaining things.

ok now thats the stuff making the heat we move onto the stuff for cooling.

this is where i have used some of my ford and renault experience to solve this problem.

the ebay intercooler kit you see what gonna be my first option but after a long and hard think i dont think its gonna be good enough for my needs, now that doesnt mean ill be going out and buying a super dear v mount kit as i think thats not needed either.

so im going to design my own from using proven methods but not paying extreme prices.

for the rad im going for, im gonna use the ebay one we have all seen, now im sure some will sniff there nose at it, but its been proven to work on a trackcar driven very hard by a race driver and keeps temps fine so no real need for anything more.

so one of these will do me fine.


the intercooler will be in my next post

[turbotoaster]

the intercooler took some thinking about.

now from the cossie days i learnt a fair bit about what coolers they run.

most of them run a 50mm core for around 500bhp, some of the bigger boys run a 60mm core with around 600bhp.

now you can get one with a 70mm core which the guys in sweden use when they bolt massive turbos on and think 600bhp is for the slow lane. these are rated for 750bhp and this is the one im going for.

Ive already got all the sizes of it and ive measured the engine bay and it fits, this is my drawing to give you an idea of how it will fit


now blue is intercooler, red is radiator and green is fans, the grey is the aluminum ducting which ill go all around the cooler so that no air is wasted and will then be forced through the rad aswell, this seems to work well on up to 700bhp cossie trackcars which get alot more abuse than this will. im sure you can guess what the other thing is lol

also it will be keeping a stock front end, the front opening will give enough air to the cooler as the ducting will make a funnel shape to the cooler, if air looses a few mph before it gets to the cooler it wont matter at 150mph+

ok fueling next

[turbotoaster]

well ill be going with a power fc, its easy to tune and pretty versatile, yes something like a motec would be better but theres some big numbers being done over in the states and money is an issue.

Thinking about injectors i did some calculations and for 650bhp a rotary needs 5500cc/min of fuel(not 100% duty)

now ross at dragon and the guys at reworx both suggested i go with 6 injectors instead of trying to fit massive injectors into the primarys and secondarys as its alot harder to map.

im sure you guys know about trying to get a decent afr at idle with 850 primarys and having to put loads of injector lag to do it.

so we talked about maybe 6 x1000cc injectors, but then that comes down to budget again.

I was watching a guy in america running 9s quarters running a stock ecu with a peter farell piggy back ecu controlling extra injectors, he was pushing 550whp which is just the number im after.

i sat and thought about it a couple a nights ago and thought how can i do it.

it then came to me, i already have 2800cc of the injectors in the car at the moment, i only need another 2700cc and im sorted, both tuners recommended 6 injectors, so why dont i put 2 x 1600cc injectors in, that 3200cc worth of fuel, more than enough, watched a few videos of some monster rx3 and he was running extra injectors in his UIM and ive decided thats where they are gonna go, on the secondary port sides(outer edges) this means i keep my stock primarys for driving around like miss daisy, also keeps my afr while idling as normal and normal driving ill be ok

sorting fuel pump etc as we speak but i have a few ideas for that at the moment.

next up is the actual engine itself

[S3TH]

You sure that turbo/builder\'s going to land you 640bhp? I\'m sure Ed will be able to help/sort you out there, the man knows a fair chunk about turbos- Though unfortunately the T88 that just went in classifieds would\'ve been your best option.

I\'m not pessimistic but like Lee, I\'ll be happy for you if you achieve it. The biggest problem I envisage is gearing, and secondly the true output of your engine.

[turbotoaster]

now a stock engine isnt as bad as what people think, with a borgwarner s475 there is a guy in america that hit 700bhp on stock ports at 32psi on e85 fuel, he says 700whp but US dynos read a little high than here and a good estimate ive found is there whp is our fwhp

after chatting to blitzboy i went back to my engine builder to talk more about his porting, he spent all weekend researching to see how much further he could go, then spent monday increasing the size of the ports again, should be interesting as they are now exactly the same as these pics below and the info on what it should run like.

stock vs big port


overlapped each other to see the difference.

the info on this says:

Same as port style 1, but with advanced port timing. Gives awesome power through the midrange and spools turbos a lot quicker. This is the port where your idle quality deteriorates. A reasonable idle of 800-900 rpm can still be achieved, but you’ll notice some misfiring due to the extra port overlap. Vacuum signal typically between 14 and 16” @ 900 rpm. This port can be customized to your specification. Gas mileage either stays about the same or decreases slightly, but 20+ mpg on a properly tuned setup is still attainable, depending on weight, driving habits, etc…. stock turbo(s) is inadequate and should be upgraded. you’ll see the best results with an engine management system.

it also makes a lovely idle from the extra overlap lol

[turbotoaster]

ok engine build pictures
engine out and bay looking a bit dirty!!


removed secondary butterflies


inlet manifolds



throttlebody

engine plate porting







Housing ex porting

nice housing surface

[turbotoaster]

engine ready to build


Engine block built


bolt ons added for running engine in




now im sure your wondering why theres still the twins etc on there, well thats because the engine needs running in and i havent got anymore money for all my big power stuff, since i dont need to suddenly make this top speed run im happy to pootle round for a bit while i get the funds together, working part time in a call centre means progress wont be lightning fast

[turbotoaster]

spoke to racing beat in america about there car to get a bit more information, i had managed to find a bit about it beforehand but these few details helped.

i knew that he was running a 20b with 3 turbos as i saw the pics but wasnt sure on heat and charge cooling what had been done, so this is the email i got back.


\'Your question was forwarded to Jim Mederer, Racing Beat\'s co-founder and chief engineer, for review. The following is his reply to your inquiry:


Our Bonneville FD had a custom chassis with no part of the stock chassis. I made the driveline tunnel quite large to allow heated air to pass through. The entire car had a carbon fiber underpan bonded to the chassis. I used a 4" thick radiator to restrict air volume while maintaining high speed cooling. Intercooling was done with ice and water to reduce drag. I urge you to use a 4" to 5" high spoiler lip to obtain down force at the rear - critical for traction and stability.

Jim Mederer\'

i did contemplate a charge cooling setup and have a few links to some kits from US but im gonna stay with my original idea

[turbotoaster]

ok while i was putting all that up i noticed a few people asked me some questions so ill try and answer the best i can

clive......thanks very much for the encouragement, things like that really help. i know adrian with 200.1mph with 650bhp, my car will have less transmission loses so that helps, also its alot more slippier than his, especially when i drop the car very low for the run to help with air traveling under the car.

lee mills.....i honestly dont think its impossible, ive never failed at anything in my life that ive put my mind to, if i thought there was anyway that this wouldnt work i wouldnt even make a start on it, the big difference between this build and alot of others i hope is thinking outside the box a little instead of going down the usual route that most people do

s3th.....the turbo aspect has been the thing that ive looked most closely at as that will make or break the car.

the t88 for example that ed was selling has a compressor average area of 7.58inches and a turbine of 7.577

my turbo has a comp of 9.7inches and a turbine of 6.65

so slightly smaller turbine but much bigger comp wheel which should still flow enough according to my research.

[turbotoaster]

one thing i havent mentioned here aswell is that the car will be running pre-turbo water injection, im making my own kit aswell and it will be a purely mechanical system so no pumps involved, got this idea from a couple of guys in america doing it, one guy runs 23psi on pump fuel on a big turbo daily, the other runs 32psi on pump fuel and has 700bhp.

this design isnt mine but im using it to give you an idea how it works.


very simple set up, good thing is, the solenoid will open at say 1bar(depends what i set it at) and the more boost you are running, the more water, so theres no need to fiddle with jet sizes once you have set it up to flow the right amount of water

also for clive...... if hes now hit 207mph he must have about 800bhp in that thing, thats out of my league, id run out of room before hitting that. theres an fc that went bonnieville with a 650bhp from a 13b and hes already up to 220mph but the car got a bit unstable on the salt so he couldnt go any faster, he said he will be able to when he gets the weight balance right, so its not all power, its distance i think with rx7s because there aero makes up alot over over cars

[BlitzBoy]

Although some Skyline boys have gone quicker then Fensport at the top speed set by a Jap car, I think its awesome a 4 pot went over 200mph in the UK
http://www.auto-power-girl.com/video-tuning/now-playing/202_mph_with_fensport_toyota_celica_gt4-1159