So here’s my story…
I have been building my car and I have been learning along the way. And one of things I still need help is determining how much boost my motor can handle. I don’t necessarily want to run it at its limit all the time, just would like to know what it is so when I can go to get it tuned I can tell them my limits.

I live in Japan and don’t speak Japanese. The tuner I plan on taking my car to only speaks very small amount of English. So I can’t ask around for opinions or help anywhere, its really frustrating. Another thing to consider is that the fuel is a little higher octane over here. I could never get a definite answer from any of the gas stations but I think its around 100 octane give or take a little bit. Also, I plan to run AI but since I am in Japan, alcohol/methanol is not an option for me. Even if I knew where to find it, it would probably be stupid expensive anyway. As of right now, I’m still broke so I don’t have a water injection kit yet. I see a lot of other street FD/FC’s here only running 1.0 bar (~14psi) to 1.2 bar (~17psi). For some reason, they dont like to run higher than that. I kinda wanted to run around 1.4 bar (20psi). That seems to be about the standard on my type setup on the states.

Some quick specs on my car:
-91 “T2”
- rebuilt motor w/ RA rebuild kit and with their “Super Seals”
-½ bridged s5 irons
-Exhaust ported FD rotor housings
-AP Engineering Power FC
-1600 sec. and 720 pri. Injectors
-HKS TO4R (.96 turbine)/ HKS cast manifold / HKS wastegate
-3 in. dp, hi flow cat, HKS catback.
-GReddy FMIC

Any help would be appreciated.

 

actually 14-17psi is about right for pump fuel. What you need to do if you can only get water injection is go for rice racings pre turbo setup. Seems like he is putting down the most boost with his setup with running water only. I wouldn't run much more than 17psi on pump gas.

 

I think the biggest danger of spending a lot of money on an engine is the fear of failure by excessive boost.

Our fuel here in NZ is 98 octane, I run my stock internal parts 13b at 26psi with no problems on our pump gas 98. But the engine is on borrowed time so there’s no big loss if things take a turn for the worst.

Im am really impressed how much these stock 13b block can take in terms of boost.....I spoke to a customers last week that imports engine parts, They have drag rx3 that originally had an engine from Australia purpose built and purchased with car. That engine finally let go after years of abuse. The amazing thing is that they replaced that engine with an import from Japan.... all stock and in used condition with start up warranty only. They have run that engine up on the dyno to 600whp at 25-30psi but drag race it at 35psi on the track. It has seen a full season now with no problems

I guess the reason why most tuners stop at lower boost levels is the fact that the engine can develop enormous amount of power for street car at modest levels of boost with large single conversions, so there’s no need for more boost at there risk.

 

The reason is, here in the states we have a lower octane. Race gas is 3x more expensive than pump.

 

yes but he lives in Japan were the fuel is better than what we have in NZ and a lot better than what you have in the states

 

I was kinda hoping that 1.2 bar+ would be safe here given that the fuel is higher octane here. And I have been thinking alot about doing water injection but NO ONE in Japan runs water injection, methanol/alcohol. AI is unheard of, well at least where I am stationed. I would need to find something I could learn and tune myself on the street. Thats the same reason why I spent a little more money to get a Power FC. No one here knows microtech or haltech, only Power FC's and FCON's.


You mean 17psi on pump gas....from the states? Fuel is a little higher octane here. Anyway, I think I'll PM Rice Racing...more money down the drain.

I get the feeling you guys think i should get it tuned to 1.2 bar and call it a day.

 

^ speak to pete his set up is awsome.... installing mine from him at the moment

 

I assume pete is Rice Racing from here?
If so, do you mind telling me how much it was?

 

Hi,

Well, since i needed mine as a custom setup, my price would be different....

plus, mine had to include airmail to Europe, that increased the price tag.....

I wouldn't want to mis lead you or discredit Pete, i am sure you will understand.

I would pm him. He answers promptly and is good to his word. straight up guy, no bull **** and very very down to earth.


George

 

Looking at the supporting mods you have now i wouldn’t hesitate running it up to max load map of 20psi or even higher.
I assume you have upgraded fuel pump?

What’s the worst that can happen? engines must be cheap in japan from the local wreckers.

 

yea, last time i checked it was ~$300 for a motor and trans, IF you can find one. and i have the RP denso pump ( http://www.rx7.com/store/rx7/fcfuel.html ). Its rated up to 500hp. Also, I have -6 braided SS lines, Aermotive FPR, and all the goodies that go with it. I think ill be ok for fuel issues.

So i asked around and basically this is what they told me. They will tune my car up to maybe 1.2 bar on the dyno. then guesstimate and continue the tuning curve based on the maps at lower boosts. Then then richen it up a little for safety. So basically they leave it up to me on high i want to go.

 

Wow $300 thats a good price. Do you think you can find me one

 

i have been here for almost 2 years and that was pretty much the only time I have seen a motor for sale in the junkyard. so its cheap but uncommon

 

I have always said a fresh healthy stock motor is totaly capable of making stupid levels of power and there is NO NEED for the BS that most Australians go on with regarding stud kits, stupid porting, banana apex seals and so on the list goes....... i know this because i have done it personaly. If you respect the stock engines RPM limitations (re clearancing of rotors) its proven it will handle amazing levels of power and be totaly durable too.

 

As an engine builder for the last 15 years i can tell you this much, ANY notable person who has done this will say the biggest singel reason to keep power down (via boost is apex seal deteriation) this is evident in alsmost every engine I have seen over time be it seals with a stock seal or the best ceramics money can buy !

THE ONLY thing that stops this phenomenon is running water injection, I literaly have seen with my own eyes engines that have been run at power levels virtualy double what everyone else does and the apex seal condition has been better or equal at minimum to what you would see in a factory engine running 250bhp over time.

You can increase as much octane as you like (to stop detonation) but nothing will stop the heat induced stress on your apex seals and rotor housings like water injection will and does (the only thing that comes close is a pure methanol race car). Its the best kept secret in this game period. Quite a few of us use it to great effect, I have my own proven system.

 

yeah thats great but im not a Power FC/tuning expert and NO ONE here that I know of uses AI. So I'm on my own when it comes to tuning the water injection and I dont have access to a dyno. Basically what im trying to ask is how much expirence do i need to correctly use water injection? Is it something I can learn and do on the "street" without any previous expirience or help?

I will have a tuned Power FC from a local tuner though to start with, though.

Thanks for all you input so far.

 

You get water injection from me and unlike any many others I am experienced with rotaries, and you benifit from this. From A to Z you get as much info and help as you want or request. It does not get much better than that especialy if your worried about your pride and joy

Best to PM me if you want to talk about it further.

 

i definitely will when time/money is not an issue. Right now im going through all retarded Japanese legal issues so i can actually drive my car. PITA

 

Because tuners can't tune worth a ****?

You know you can retard the timing enough to avoid detonation even on lower octanes. But some people like every ounce of power without keeping safety in mind.

I don't blame them, but when you're talking about cutting out 20-30hp and adding some reliability, i'm down.

Also, all about the water or methanol injection... that **** does wonders. Nice piece of mind, only downside is you have to worry about another component of the system that can fail and ruin ****.