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Super Sakura Dominator
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I didn't know that a bigger pump and injectors will yield any power gains on the stock turbo....
Read the part again where Leftbehind126 posted. That guy was asking how to make 300WHP.

As far as upgraded fuel pump and injectors, a stage 2 GR will max out IDC's. (As seen in the ECU forum) It is recommended that you upgrade them to get the most out of your performance.
 

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here is what is truly important. get an experienced builder using quality parts, get an experienced tuner who knows what the hell he is doing, don't rape the car, and regularly check hoses, wires, oil, etc. etc. and it will last a while even with 400 or more whp
 

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Thanks man. This was a very thorough and informative thread. I might just pick up a 2012 STI and leave it stock. I don't need to get excessive with a brand new ride, as long as I still have the fun factor with the handling.
 

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Question for professionals...

Artech Power has built this monster engine aprox 2-years ( I bought a new JDM STi MY10 engine from Tommi Mäkinen Racing ). I took the car in use few months ago and after we tuned it in Dyno, I only drowe 1500-miles and we lost our engine Cosworth 1.1mm head gaskets and also both of the front sylinders got exhaust valve burn/lead issue...( +1mm larger Cosworth exhaust valves ) This is extremely rare in street use. AFR in full throtle is 11.5 . We started to believe that something was wrong with the engine, but what??? Ok, we overhauled the heads, added new exhaust valves, new head gaskets and we checked the compression from all sylinders. OK! When we started to tighten the Cosworth head bolts to correct order/tighten, leak problem started again, so exhaust valves started to leak again after tightening + heads camshaft line was also uncorrect...So the sylinder heads starting to bent??????? Have you guys heard/faced same problems??? That is new for us... We heard that some of MY06 up Turbo Subarus and new Mitsu Evos got same sylinder head problems too. Maybe aluminium combound are crap in these days?? Old Subaru heads do not have this problem at all.... The heads were brand new big ported OEM JDM ones. Can we do something about it or are we going to lose these rare/beaty heads?! Now we have slightly ported MY08 US STi stock heads with stock valves. Engine pull still strongly but it is not as sharp as it was...

Block deck surfaces is also checked and it is Correct/OK!

pics of heads...



 

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I'm at 386whp now on 91oct + Alcohol. I had a pre turbo exhaust leak on dyno day that I didn't know about, but it's fixed now and I'm getting tuned on the 1st of Oct.

How much power can the stock engine block achieve with E85 safely? I know the fuel is safer, so maybe 400whp reliably?
^^^Good question, I want to know too :D
 

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YES There guys out the making 450+ HP on a stock block. It can be done... Its all in your setup.

and

NO! If you want a reliable 400+ whp, save your money and time and have it built with all your bolt ons the first time, get her tuned and call it a day. I'm speaking on behalf my experience. It is smarter to have all your bolt ons all installed on the same day so youre not spending all that coin with tuner expenses... And with all that power, stock pistons/ringlands become an issue. Best of luck to you :tup:
 

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How much power can the stock engine block achieve with E85 safely? I know the fuel is safer, so maybe 400whp reliably?
This is not an answerable question. If E85 is safer it is only because it may not fry pistons as easily, but bearings are a function of oiling and power and they could go just as easily. Not to mention bolts, head gaskets, etc. Good luck.
 

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The stock bearings, rods, crank usually last a pretty good while on 400whp builds. It's the pistons that are a weak point.
 

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Once the piston goes, hopefully you'll make it back home. LOL! I was lucky when mine went... I was cruising with fellow STI and evo guys up the back roads and canyons, the guy behind me was filming using my goPro and I heard him say. " I smell burning oil" ... I take it thats where my pistons gave.
I ended up driving the piss out of my car for another hour before I noticed anything. No oil light, nothing... until I stopped to fill up with corn juice and to BS for a while. I started her up and it started going clack clack clack clack clack. Too late, I had just fried my bearings and had serious rod knock...
I made it home 12 miles... Later on I tried starting her, she would crank over after several tries and I had to give it gas to keep it idling. She eventually seized.
Long story short. Shit happens, especially if you do the high speed back road thing or track. here's a link of the vid. punchjames socal STI and EVO vid 3 - YouTube
 

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Re: Your answer to "I want 400whp"

they will if they wanna save money and have a 400whp car tomorrow and next year...haha

then again by the time you've invested the research to build a 400whp car and talk to a tuner you damn sure should've learned most of this along the way...either that or you've been talking to the wrong people... I'm in the process of doing a GTX3076 ATP turbo EWG and supporting mods myself...and I fully intend on seeing how long the stock block will run :)
Me too!

How did it turn out for you?
 

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It's not the just pistons that are weak, it's the ringlands and then the pistons. The pistons are designed to run moderate power for a Very long time, upgraded pistons (depending on the alloy) will sustain more abuse but because of the softer metal they will not last as long. You can build a 400whp stock block car no problem but it will only be a matter of time until the rings fail then crack a piston and you spin a bearing. My buddy Dwayne had a 398whp stock block 04 sti with just a 30r on it. It's possible. I suggest a built bottomed and a GTX3076 with tgv's deletes, upgraded fuel pump, ID 1,000 cc injectors, intake, upgraded BOV cycled back into the intake track, AOS, 4bar MAP sensor, 3" exauhst, and an upgraded FMIC. This will garuntee you your goal and leave you room for more power with race gas and possibly meth. Afterwards you can do headers and head work for more hp and maybe a bigger snail down the road.

Thats it, close the thread.
 

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My buddy Dwayne had a 398whp stock block 04 sti with just a 30r on it. It's possible.
There are too many variables for something like that though. It can be misleading when someone says "XXX on stock block." How much HP? How was it tuned? Aggressively? Conservatively? Daily driven? Raced? Etc.

A local had a 35r on the stock block for years before it finally blew. Want to guess how often the car was driven though?

Thats it, close the thread.
:rofl:
 
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