I love how the camera guy suddenly realized the pinup calendar was in the shot and panned over.

Love the info! Thank you for making these videos!

Keep up the good work. Thank you for all the helpful videos you done!! always good to learn new stuff, Especially in the middle of a build.

When trying to match cams with a turbo, my first reflex would be to take cams with an hurley exaust valve opening and a longer overlap time with the inlet valve (high rev cam design) to compensate for the spool up restriction. If there's some air/fuel mix lost in the manifold between the exaust and combustion stroke and pressure remaining from the combustion then it will help to spool up the turbo faster.

Nice! this was great info to know!

i wish i would have ported my heads when i built my motor, it is now my limiting factor. good video

@maxxjettfilms6322

7 жыл бұрын

VIsubby i have 404whp on pump and as i tried to raise psi past 22 psi my gains were minimal. now i could get a bigger turbo to over come my flow issues but would gain more lag as a result. it is far from scientific for my particular motor, but if i could move more air through my 2.0 heads more efficiently, i could make more power with a mild boost increase with my turbo.

@seatmaz

5 жыл бұрын

Stock avcs 2.5 heads can flow enough for 500/600 bhp .

great series

this is a top tier build, could have gone to dimpled design flow chamber, that would have the same exclusiveness as the block has.

Thank you you did a video!! I need to see part 3! I mean, I need to see everything about EJ25, so I can have the knowledge to know what I need and want to be done on my '09 STi Hatch! I need it AS RELIABLE (with proper driving of course) AS IT CAN GET. Actually on 400HP, but later, I will want to move to around 600HP, but only if it handles top reliability.

good work and good video ..

I was waiting for this head falling since 0:24

2:44 that cylinder head fell , but nice talk on the heads on Subaru

The two dislikes on this video are from the cams in the head that tipped over XD

In my experience porting and big valves along with supporting mods gives you the same increase as it does on normally aspirated. To give an example of what it can do, there's a guy running a VQ37 naturally aspirated that puts down 557hp at 8000rpm. That will smoke a stock GTR. So done right it can do an insane amount. That VQ37 would make around 1000hp on 20 psi of boost on E85. How much boost do you need for a stock head and cam GTR? You would need 35-38 psi boost to hit it, 1 bar more than the race ported and cammed engine. Obviously both would need built bottom ends. But the idea is clear. Porting and Cams is the first thing if I open a motor 😍

@MRTPerformance do you guys do any work on mitsubishis? Id love to hear what you have to say and any cool info you can give me on the 4b11t engine from your experience! The things you share are unique compared to what a lot of people make videos on. You give a different perspective on engines and reliability through your exerience, i love it.

@invertedv12powerhouse77

6 жыл бұрын

Callan P.K. he has videos on evos

So do you guys build the heads yourself? And port out and polish the factory head? Or do you buy a whole separate already ported complete cylinder head from a distributor? I would like to know where to get a complete assembled built cylinder head like that.

@mrt performance is it worth running a ported head on a stock shortblock?

Any benefit of building a 2.0 bugeye motor? Or should you just build a hybrid? I heard you can take a 2.5 sti block and stock 2.0 heads and it would work. Not looking to run stupid amount of power. 300-320 maybe

What is the logical order of head modifications on EJ25 , in my case SOHC heads with delta 1500 cams.. 3/5 angle valve job... port and polishing, bigger valves, etc. Planning around 23psi @ 6850-7200rpm (Centrifugal SC).

have you found any benefits to milling away some of the combustion chamber to reduce valve shrouding but making a more rounded chamber?

@MRTPerformanceAustralia

6 жыл бұрын

not worth the gain :(

awesome vid. how much airflow was gained (at what lift/pressure) from porting? was there more work like a valve job to complement the larger valve size or was it deemed unnecessary?

@aggnal2892

7 жыл бұрын

VIsubby. titanium valves are lighter = less reciprocating mass, do you think or do you know for sure they use titanium for strength?

wasn't this engine in a liberty project car?

Is mtr performance still going????

hmmmmm, you know the prodrive v1 ej20g heads were cast in house by prodrive - that the ports are actually SMALLER but produce more torque and power, there is a supplier in UK (i think) that sells billet heads that incorporate the prodrive design to a billet head with some mods, according the the website they go pretty good haha

@burrowssj

7 жыл бұрын

Well, prodrive were building a rally car, so top end power was not a priority as much as low down torque and response were, I really don't know the details/numbers I imagine the prodrive heads are not so great for higher power, they probably made up the power else where in the setup so the response gains probably out weighed any power loses. My comment was more for the random interesting information point and in the hopes to see an mrt video on a billet block and heads build/dyno/run down/show off . Go on guys you know you're as curious as I am, no one seems to have done it yet :D Billet block and billet heads, dooooooo ittttttt!!!1

@burrowssj

7 жыл бұрын

and this also was in an era where shim under subaru heads didn't exist. Hydraulic was what was in the street cars. I'd say the first production prototypes were inspired around the rally car head design/RnD by pro drive , and prodrive probably got inspired from a bike manufacturer lol

so the cams and valves are key. the rockers and Springs wouldn't need to be upgraded on the head to work with the new valves and cams?

@AutoBodyEverything

6 жыл бұрын

I wouldnt use any stock parts that work in conjunction with aftermarket especially moving parts. Upgraded cams with custom lobes change how the valves move and the speed of the valve to to keep up with the stress and performance of those parts you want strong and reliable springs that are made with the metal composition and dimentions to meet the requierments.

good old fashion engine building.

Now you just need to anodise the heads gold as well (Y)

Hey, Brent would you recommend buying a high mileage STI?

@KAVINSKY311

7 жыл бұрын

as long as you budget for a full engine build

@dominicancheif117

7 жыл бұрын

***** around 120,000 miles, those types of sti are in my price range, and they are my favorite style. (The 04 and 05 blob eye)

So if you are modifying a subaru, upgrade the entire pistons to forged

@MRTPerformanceAustralia

6 жыл бұрын

yes

Can you stroke a 2.5 engine?

@AmirPomen

7 жыл бұрын

i think i've saw somewhere there is a stroker kit for 2.5...that makes it around 83mm stroke

Isn’t it true that having a slightly rougher port rather than a polished port actually flows better because, the rougher port causes the air to have a turbulent effect on the air flow and causes the air to swirl and actually flow better than a highly polished ported surface...????

@emmo584

4 жыл бұрын

kzread.info/dash/bejne/dGmi0c5vhNi9pqQ.html

Is there anything Brett doesn't know about the Subaru

should go water to air inter cooling on this build

@ElMosqito

7 жыл бұрын

I would say air to water

@KAVINSKY311

7 жыл бұрын

ElMosqito why?... does the air cool the water?

@ElMosqito

7 жыл бұрын

It's all about heat transfer. If you want to cool down air by water you need to transfer heat from AIR TO WATER. That's wy i would call it an air to water intercooler

@KAVINSKY311

7 жыл бұрын

lol your describing a radiator... anyway I'm sure your in the right and everyone else on earth is wrong. lol

@KAVINSKY311

7 жыл бұрын

why? this will be running on e85 which is better/cheaper than meth and cheaper/safer/ more efficient than nos.

Don’t run stupid boost! Haha, good one.

Hog it TF out!