Katana

e-volve has nailed it correctly. If its a closed deck block, it should last much more than the open deck ones that the newer ones uses. You can try to extract more power than that, but then you've got to worry about other things like conrods, pistons etc. I say don't go more than 350 for now if you can help it or unless you can get more spare cash.

Don't forget uprating your injectors (we've got puny ones) and fuel pump too while you're uprating it. Especially the fuel pump as its old and you don't want to take any chances, especially if you're boosting as much as I did then (23 psi held)..

edit: I'm slowly starting to do up this RA. If my MY93 could take the power I had, then my 95RA should be better. Of course this is assuming that the fifth injector really does work and is not a cold start valve like some people say.

[Edited by Katana - 12/2/2002 6:18:53 PM]

Katana

Cheers mat.

Upon inspection, the pistons weren't the original ones and was a forged one (guess ). It had a full decat (dunno what type big bore exhaust) which I've managed to retain for my current car. I used some Blitz sparkies (took it out also and put in the HKS one back in before I sold it) for it and the usual dawes, fcd, afr and such. Thats all I can think of performance-wise for now. She really held up at 23 psi.

I'm only running at 1.3 Bar as of today. Dunno what that is in psi as I've forgotten (long day today). I think you either multiply it by 14.5 or 14.7. Great engineer I'll be eh?

[Edited by Katana - 12/3/2002 9:37:44 PM]

Katana

The other problem with overcooling your combustion chamber is that the gasses has to work towards combustion temperature, hence robbing you of precious power. There's a magical temperature for it all and my bag is still in my car so I can't tell you it.

Oh Steve, you didn't think you can get power for nothing eh?

edit: Its us engineers who discovered the magical "Mcauley's Brackets", simplifying stress analysis that bugs you maths and physics types. You guys must be kicking yourselves in the butt because of this.



[Edited by Katana - 12/4/2002 6:44:58 PM]

kev93wrx

Recntly had feedback from you about the series 1 being a stronger car.Mines a wrx import from cyprus not the ra version though.As you guessed its a my93.How far can i go with tunning it.I know the history of this car from new and it does have low mileage and service history.I know tuning old high milers not good.

e-volve

mines a WRX MY96 55k on the clock
Ive added a
HKS METAL FLOW
HKS SSQV
HKS HYPER Stainless system including front pipe and de-cat
Apexi Turbo Timer

Penciled in for January are:
HKS Frontmounted intercooler
Apexi Power FC ( ECU )
Apexi AVC-R ( Boost controler )
18"-19", not sure yet
and a full RC DEVELOPMENTS RE-MAP and boost upgrade

all this should be good for a healthy 350bhp.. and a safe one at that.
in the pipeline is an Apexi or Greddy Hybrid turbo

looking forward to next year BIGTIME.....lol

Adam M

Katana,

just a quick note that worries me.

you seem to think the closed deck block is the be all and end all of the strength of the engine.

It isnt.

There are open decks in the states and aus running over 400bhp.

The problem with the open decks is that without the support of the extra metal, the cylinder walks at high boost and as a result the seal with the gasket is compromised. This can cause the engine to hydraulic or emulsification of the oil.

Equally just because a closed deck block stands a chance of surviving 400 or more hp, doesnt mean that a closed deck equipped engine can survive it. All it does it strengthen one of the links of the chain. There is no real evidence anywhere to suggest that the open deck is a particularly weak link anyway, so this feature in itself should not be relied upon so heavily.

in my opinion, it is much mroe important to sort out stronger rods, the real weak point, and then in the absence of sti pistons, uprated pistons of another make. You can always improve gasket sealing by wire ringing the block, as this will also allow you to run more boost.

(have just looked back at this post and it seems really patronising - sorry if thats the case, was not intended to be that way)

Adam M

further to this, andy f made it clear that his fith injector did nothing!

Katana

Adam I know what you mean. Thats why I said what I said in the other thread. All it means is that the block can take the abuse. I'm not however going to stick with the same internals over the months do. I'm gonna change it bit by bit (conrods, etc) till I'm bored with it and then flog it.

Oh, and don't remind me about Andy's 5th injector thread. I'm still getting nightmares because of it.

tweenierob

Katana, you must have had some serious power @23psi :S
I got just under 320bhp @17psi (MY93WRX) i think another 6psi would make me change time zones
What mods did your last car have??
Love the new beast by the way mate
Rob

tweenierob

LOL i went to the same engineering school
Are you going over to The Pod in Jan??
Deffo gonna be there
Rob

Katana

Most definately mate. I've got to test out colin's and his mate's new top secret invention there.

Oh, I've got in front of me a book on "applied thermodynamics". It gave all the conversion from Bar to something else *except* psi. Maybe they don't know too.

Adam M

14.4 I think!

Americans think differently.

you'll be a fine engineer.

As a physisist we are trained to hate them. They get to the complex bit at the end of calculations where their maths runs out of its depth, and they fudge it over until it works.

Whereas we as mathematicians essentially, plough on until the numbers work, use our calculations to build things, and find that nothing works!

But at least we know our theory was flawless

Turbo_Steve

So that's your secret! You had forged pistons!
And there was me thinking I could go the smae routewith my engine (TD05, remap, fuel pump, MUCH larger charge-cooler radiator, bigger injectors, maybe water injection) but all I am going to do is blow my brand new WRX bottom end, isn't it?

-sigh- I just wanna get mine to 320bhp without ripping the engine out!

Oh well...in the meantime, I think it's time for a dawes device to fix my over-boost problems.

forged pistons

Still...your car was DAMN quick

caz1562

14.5 PSi = 1 Bar

23PSi = 1.586 Bar

I know, I need to get out more !!!!!

e-volve

you dont need forged pistons to get over 300bhp!!!!
just stay under the 350bhp mark and your motor should be just fine.
uprate your fuel pump and get a re-map...maybe even a new ECU
( roll on Jan for my APEXi ) and a good boost controler, and for christ sake, get it set up by sombody who knows the stuff....as a dodgy re-map can dash your hopes of 300+bhp.....
And avoid sill boost levels there is just no need for them,

see my spec above and my spec too be.........2003 is gonna be a good'n....

I wait to be corrected.......lol

good luck anyways......keep us posted on the progress.........
all the best and seasons greetings
jay

Turbo_Steve

Unlikely to acheieve 350bhp on a VF11
If I am gonna spend out on a TD05 or Hybrid, I might as well see how far I can take things without going internal.

I am assuming the pistons would still need changing even if I used water injection to lower the temperatures?

e-volve

The pistons would be a great idea, and to be honest i would love to change mine, but i WILL crack 350bhp out of mine ( MY96 ). but for me 350bhp is my stop point..anything after that and your into big £££££

Water Injection scares the be-jesus outta' me as the idea of water and fuel in my chambers is a idea i cannot get round my head, please feel free to Gen me up on this procedure as i know nothing on the topic

jay

Turbo_Steve

Not 100% sure about the details of this myself, as I have always found the idea of filling up an extra tank with water a bit of a no-no. If you have a custom ECU fitted, you can alter the maps of the car for "With" and "Without" water, allowing you to have a simple on/off switch for more power.

As long as you have a proper water injection kit, I don't think it is particularly dangerous. It's a bit like Nitrous: use it wisely and you will not have any problems.

Technically speaking, I think you will find that the cylinders fill with 'mist' more than water (water in the cylinder would result in bore wash, something you don't want) which leaves as 'steam', reducing both the temperature of the charge, and the cylinder temperature. I believe it also slows the flame-front, though I am heading out of my depth now!

As I understand it, the main benefit of water-injection is not that it gives you more power directly, but that it lets you significantly advance your ignition, resulting in more power output with reduced danger of detonation. What I am very unsure about is the more technical aspects of water injection, and whether or not water injection let's you "off the hook" for an extra 25bhp or so with regards to piston strength.

I am not clear as to whether it is the surface of the piston that is not strong enough, or the actual armature simply cannot take the force of explosion required to generate more than 350bhp or so.

Is it the torque or the temperature that 'does for' the Subaru chocolate pistons?

carl

Yeah, right
Physicists get an equation with two solutions (e.g. x^2=4) then ignore the one that's negative, saying it's "not a physical solution". Mathematicians would spend their time worrying about the negative solution.

e-volve

I did look into a 50bhp shot of Nitrous just for the "Fun Factor" but at the moment im gunning for ball's out grunt and not a "quick fix". maybe if i get the block and pistons uprated i will have a dabble with the funny gas, but for now i'll leave it ( says this but has a bottle waiting to be filled and the kit to fit it under his bed....IT WAS CHEEP SO SUE ME ).

Ill gonna lookinto that water injection melarky as lowering the engine temp is always a good thing.....

I belive Cadburys do a great replacment piston set for the Subaru

Turbo_Steve

"ignore the negative one"????

Um? Anti-matter?

While we have all these bright people here.....I was hoping to find someone who can advise me on gas-flowing the plasma conduits in the warp core of my interpid class star-ship. It's a MY2342, and I have a flat spot at around Warp 4. I was wondering if fitting anti-proton injectors would help, but I am not sure how to configure the polaron emitters?

Seriously: Anyone know whether Subarus have chocolate pistons or weak bottom ends?

Turbo_Steve

Use a few VERY quick 25bhp shots of Nitrous at low revs to overcome boost lag?

Adam M

guys,

need to clear up some things.


water in the cylinder may well cause bore wash, but I would be more worried about the engine hydraulicing.

bore wash will kill you over time by oil starvation, hydraulicing is like trying to compress eg. a stone. It isnt going to happen!


water injection is no problem at all if you use the right size jet.

It doesnt give you more power like nitrous as it cannot be burned (you arent going to split the water up into hydrogen and oxygen in a hurry in an engine!) and so all it is doing is taking up the space of fuel in the cylinder.

this costs you power, whereas nitrous adds it by supplying more oxygen.

the water will be mist if you run enough pressure and the correct size of jet. The amount of water we are talking is tiny.

If you are afraid, then what do you do on humid days? not start your engine in fear?

driving in fine mist is ideal for turbos! for a start the air is much denser and so yields more power, but more importantly the water suspended in the air is boiled by the charge in the engine.

as water boils it stays at the same temperature yet takes energy away from the surroundings the break the hydrogen bonds between molecules. This means you can take energy away from the engine block without raising the temperature of the charge.

Over a number of cycles it reduces the afterburn temperature of the engine, and ultimately its operating temperature, which brings down the chances of det.

It allows you to run more boost and more ignition without detting.

You can add water at your existing point and it will cost you power but give you a larger safety margin, or you can add water then advance the ignition giving you more power than you lose by adding the water.

Is a very intelligent way of increasing the safety of the engine and should not be viewed in the same light as nitrous.

By the way, when the fuel burns, the combustion will create a massive amount of water, so if bore wash is your concern, it shouldnt be!

Turbo_Steve

Cool....so I was spot on about everything except the bore wash
(I thought that was the only potentially ill effect).

I know it doesn't give you more power, hence my statements above: it gives the the ability to tune the car more aggressively.

The difference between water injection and driving on a misty day is surely that you can (note CAN not DO) fit water injection AFTER the intercooler to provide the maximum effect. This means the 'misty' water doesn't go through the turbo charger or the intercooler. Whether that makes a difference I dunno. =shrug=

Anyway if it lowers the cyliner temperature it HAS to be a good thing!

My only reservation is that if you tune the car aggressively enough to REQUIRE the water injection, what happens when I run out of water? I suppose the easiest thing to do is have a relay and a water level sensor in the tank: if the level drops, the boost solenoid is disconnected so that the wastegate stays open, reducing the boost to approx 7 psi.

So: sounds like Adam is a believer in water injection, and that it will reduce cylinder temps....so possibly negating the need for a set of forged pistons?