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If I had a shop and someone came in asking about an engine build using those cams I would say the cams are built for high horsepower drag type Subies with a power range of 500-750WHP (on my Mustang) and a rev range of 4500-9500rpms.

I would HIGHLY recommend beehive springs.  I would HIGHLY recommend porting the head.  I would HIGHLY recommend "building" the head as you need to add clearance for the extra lift. 

I would also HIGHLY recommend a whole bunch of other upgrades to support the build.  A closed deck block would be one of them.

If the potential customer did not have the budget for the proposed build I would recommend not using those cams.  If the potential customer insisted on using those cams but not my HIGHLY recommended upgrades, I would decline to build the engine. 

IIrc I used those cams on one daily driver.  The customer had two STi's the same year and color.  Its a long story.  He did take my advice on all the upgrades.  He did not drive on public roads like they were public roads (he was a foreigner).  He was mofo scary in almost every way.  GAWD I loved that guy, he was my favorite customer. 

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37 minutes ago, m sprank said:

  I would HIGHLY recommend "building" the head as you need to add clearance for the extra lift. 

Could you elaborate on that part? Add it where exactly? Cause these cams according to BC require no modification to the head at all. That's why I went with them as opposed to the GSC or Kelford. The BC cams are milder compared to the GSC and Kelford when comparing the stages. 

As for the springs, I used the ones that BC recommended for their cam. 

So far everything has been working just these small annoying issues that require me to pull the motor. But overall they seem to run fine on the street.... I'm that guy on the road lol! 

My only concern is its running rich to the point I smell gas in my oil, but I have some simple etune atm to break in the motor.

My build was to start with my 20g turbo get that dynoed to see where i'm at, and then the next major mod on the table was a monster ATP Garrett Gen 2 GTX or GT turbo, which I could use with grimmspeed tmic using the adapter piece they sell. Then after or at the same time I would upgrade to the cobb flex fuel kit to run e85/93 octane mixtures.

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My bad.  Old age.  I missed the Crower brand.  I used GSC. 

Comparing the two they are similar in duration, but different otherwise.  I would have gone with the BC0610 spring kit if using Crower. 

GSC:

Intake 282 / 240 @ .040" / Peak Lift 11.3mm / Centerline AVCS
Exhaust 282 / 240 @ .040" / Peak Lift 11.3mm / Centerline 113

It appears you do not have to clearance the head for lift.  However, I would still recommend porting, beehive/dual springs, new guides, oversize valves, TiC FU cam bolts.  I want to say 1/2" headstuds and JE Proseal head gaskets as well.  I would pair that with a closed deck block, ARP case bolts, jdm 12mm oil pump, KillerB pan/pick up/baffle, RCM timing belt tensioner and idlers. 

Need a big build to use those cams properly.

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To late at this point lol! Dice have been rolled! We will see what happens when the dust clears! 

The valve clearance for oem versus these cams are different, and the tolerance seems to be a lot higher.... adjusting buckets again is going to be a pita, seems like the original guy who rebuilt my heads noticed this which is why everything was so tight, and then like a noob I went and put them back to oem specs...... wtf 

The one thing I do want is to upgrade the tensionser. I was looking into that for a while. 

Everything else is in gods hands! LET IT RIDE! 

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TY, I will need it! 

So the reasoning behind going with the stage 3 bc cams wasn't to make disgusting amounts of power but to just move the power band to right. I don't want 400-500hp at 5-6k rpm, I want it 7-8k rpm. From driving the car so far on this crap tune all I can say is it's a lot more fun when you move that power to the right. Of the line its blah, cause I'm not dumping the clutch but  lets me just cruise  around 3k-4k, after 3.5-4k rpm its all business. And I have a fuel cut at 6 or 6.5k rpm for break in reasons so I haven't even given it the beans, and its obvious its still making power at the cutoff, like someone walks in on you and your woman and you are rounding 3rd and about to score a run lol. 

From my knowledge moving the power curve to the right isn't simple with these motors, so my theory was to just find cams with a lot more duration for more air, but not so much lift, from my experience duration is more important, and from what you said lift is obviously a bigger pita, ie you gotta modify the head to take the added lift cause of the taller lobe. So short of having a custom cam made, I went with mildest(lowest lift) cam with the most of duration.

I could slap on a bigger turbo and get more hp, but that was never my real goal! I want a wider power band, hp is the 2nd goal. I don't need earth shattering hp, I just want my max hp to come at 7 or 7.5k rpm. 

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You picked the wrong engine design. There is a reason the horizontally opposed falt 4 makes low end torque, but does not breathe well up top.  AVIATION. The original intended use and engineered design.  

Edited by m sprank
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True but how much r&d goes into such an obscure motor? Domestic motors have gone through all sorts of testing both by normal consumers and companies, compared to boxer engines its leaps and bounds ahead in the research department. Subaru motors are like an extreme minority when it comes to the world of engines, I would say the only thing more obscure is the rotary engine from mazda. V8,v6, inline 4, inline 6 .... compared to those wtf is a boxer engine? Thats why u have so many variations for a v8 motor or even a honda motor.

I wouldn't say its cause of design, I would more so think it's more along the line of who is putting in a bigger cam for just higher rpm and not hp and who has done the actual proper research and documented it? Everything I have read about cams for a subaru is basically armchair, nasioc is cool and all but its also poisonous in my opinion. Nobody's really doing the research cause, why bother? Not that many turbo subarus and not that many people who give a shit about those fine details like spinning to 8k cause they can get it early. I don't even see useful articles or posts about stage 3 cams .. its all armchair bullshit. 

Has anyone in the import scene done an article like that for the ej25 motors? Ive searched the internet and tbh subaru motors are just lacking in the information department. You have motortrend and whatever magazine doing crazy dynos to get results for anything and everything domestic meanwhile everything boxer or subaru engine is tight lipped and obscure. Its a pita setup to even work on , a god damm 4 cylinder with 2 heads and 4 cams? Eww! Might as well get a v8 at that point lol. I just think the engine has not really been explored and documented. All you see are forum posts about he said she said, where are the professional journalist when it comes to cams and subarus?

The world doesn't care about turbo subarus cause they aren't really the common mans car imo. Anyone can get a v8 or I4 from the junkyard and make tons of hp, compared to ej motors which are a lot more rare. And with that comes very little data and information. 

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Subarus engines have over 100 years of r&d.  Read up!

 

https://en.m.wikipedia.org/wiki/Flat-four_engine

 

All you mentioned was interweb BS. There has been r&d.  Its not "published" because education is not free.  If you know who to ask, its all been done before. John Ronkowski (the innovator copied by all others) has spent millions of his own money building and developing Race Subaru engines since the 90's here in the US alone.  If you call his shop he or Jeremy will share tons of "inside" info if you ask nicely.  

Edited by m sprank
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I hear ya, but thats why its annoying, domestic and more common motors have tons of published information..... which is why ejs/boxers suck in that aspect lol. 100 years and no real published material other than this motor is flat and works like this lol? Domestic/Common motors have like 100s of these John Ronkowskis.

But it makes sense,  from a business point of view why invest r&d in a minority market with a low amount of performance enthusiasts, when you can invest that r&d into something more common like a honda, Honda makes at least like 5 times more cars yearly than Subaru to put it in perspective. Larger audience, more parts to sell. On top of just needing so much effort to work on the car makes everything expensive. Like a rear engine car, these cars are a pita to work on which equates to more money in labor charges compared to other cars.

If you wanna do ANYTHING, gotta pull the motor lol. Most cars you can pull the head without much effort, and all this fuckery. Instead of paying someone for some headwork you gotta pay for engine removal AND the head work. Thats why all these turbo subarus get tossed in the garbage when they break. 

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Subarus are "quirky".  It used to be what made a Subaru a Subaru.  Until recently sales were low.  The enthusiast market was strong, but small in comparison.  John has used to post videos.  But, he has been copied so many times now, he gave up.  It is SOOOO expensive and time consuming to learn to do it right by trial and error.  Its equally difficult to make money building Subarus.  Every bit of info you give away for free is 10 potential customers who will now never show up.   Subarus have become like Hondas in that way.  Its all about working on them over the weekend in a Facebook group members front yard.  Everyone's a shade tree mechanic who can do anything. 

 

You yourself are now going through heartache and money learning the hard way.  You could have placed a single call and had the engine of your dreams shipped to you and they would have explained everything.  You have to pay to play.  Sometimes doing it yourself is good, and sometimes its not so good.  I have bitten off more than I can chew a few times too.

 

I wish you the best in your endeavor. 

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On 10/28/2022 at 6:18 AM, Tehnation said:

If you wanna do ANYTHING, gotta pull the motor lol.

Yeah but honestly, they aren't that hard to pull. NA EJ's are basically on a zipper, and the turbo ones aren't much harder... the na FB's are practically velcro. I can have an FB on a stand in 45 minutes.  My coworkers and I are always joking about pulling the motor for simple things just because of how easy it is.

Edited by silverton
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Redid my buckets, seems like I need to order 4 more. Exhaust are at .25mm and intake are at .20mm. So this time around I didn't bother using a micrometer. I realized it was kind of pointless when my feeler gauge is highly inaccurate, ie .20mm, .23mm, .25mm .28mm.... with those kind of readings there really isn't any point measuring the buckets with all that discrepancy. So I just measured all the clearances with my feeler, pulled the buckets, looked at the numbers and adjusted it purely on the numbers on the buckets. This made it a lot faster and easier. I put em back in and my driver side is perfect as it can be with my feeler gauge(basically .20mm worked and .23mm didn't or .25mm worked and .28 didn't) so basically up to +.02mm of inaccuracy , passenger needs a little work, I can force it but might as well just get 4 buckets. 

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 (derp, a few posts up, "stage whatever cams" lol) sorry I haven't followed completely, do you have an aftermarket cam or OE?  .25 on the exhaust is way too tight if OE. Spec is .30-.40 with .35 being ideal. 

I've only ever adjusted buckets by taking a measurement and going off the number.  every 3 is a thousandth.

Edited by silverton
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Scroll up to around october 24th posts, it has all the specs. I overlooked the valve clearance specs for the aftermarket cams, I did oem, which aren't what the cams require. OEM is like .2 intake and .35 exhaust with a wide range of tolerance + or -, My cams say .20 for intake and .25 for exhaust, so I had to change them from oem to BC specs. 

The number on the bucket is the thickness in mm, so a 490 bucket is 4.90mm thickness. I use mm so its pretty straight forward. like a 4.90mm bucket with .30mm clearance means I need a 500 bucket or 5.00mm to get it to  .20mm clearance. 

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I like how you said your building a street car lololol 😄. Reading your story and the stuff your going through I am so happy I just had a shop do all my stuff and they know Subaru's. I really thought about getting a staged block, but just went different route. It's cool to see you doing this. I am following your post. A closed deck is the way to go. 

 

PSS You gonna need that STI 6MT 😀

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Not my fault lol, I say a streetcar cause have u seen what cars are doing from the factory!?? M this and AMG that, Turbo this and Supercharged that.... even electric... 20 years ago 300-400 at the wheels was enough to rule the streets and highways..... now they are putting that out straight from the factory lol. 

I'm not looking for extremely high hp and high rpm, just high rpm with anything above 400awhp. More so highway driving, nothing but highways and interstates in this area, so I want top end power not low end. 

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