A step backwards in prep for a huge leap forward.

I've broken 2 rear ends thus I am in some debt. I am not a drag racer any more. I am seriously bored with it and I constantly find myself wanting to rev out the car and enjoy it.

What are my future plans? JDM 6 speed with R180 rear. Taking care of all the weak links in one shot. Axles are cheap enough so I'm not worried about it.

The short gearing doesn't bother me.....I've got a 2.5L block sitting in the garage that Ron @ Axis Power Racing will be working on when the time is right. It's gonna rev out to 8500 rpms so that 6 speed will be used as intended. Not short gearing at that point.

Hmmmmm 2.5L + 8500 rpms + 420-450 hp = one hell of a fun machine.

 

GTScoob will have that badass redline I'll just have the tq sooner :naughty:

 

sounds like a step in teh right direction to me

 

thats not backwards, thats FORWARDS.

 

yes agreed...nice decision.

 

We should make a symphony of high-revving subarus. That sounds like a killer setup.

 

Yep twin scroll is gonna be sick if GTScoob can get a turbo fitted.


I talked with Ron and it's not 'that' expensive to build the 2.5L. I used to be against building a motor but Ron know's his stuff.

Basically my stock WRX heads will be utilized with cams, springs, and retainers. Stock valves are just fine. Voila 8500 rpm heads. Stock EJ257 rods are just fine. Forged pistons, custom crank work and all blueprinted and balanced to 10K rpms. Voila 8500 recommended redline block.

Slap on a nice turbo like a GT52 or greater and stay under 28 psi with a Super Siegel tune and you have a WIDE powerband that is hella fun.

The PPG's are just not as practical as you would think.

 

Kinda bad when you can upgrade to a JDM 6 speed and a R180 for cheaper than just a PPG gearbox isn't it?

 

So when I get the jdm gearbox, should I opt for the version 7 non-dccd gearbox or get the version 8 dccd gearbox with the hardware for the dccd?

 

Damn. I would have swapped gearboxes with you straight up. Why didn't you post up here that you were selling.

 

you can get a manual DCCD controller....the DCCD diff is MUCH stronger than the version 7 VLSD.

 

It was a fast move.

 

That's what I was thinking. Getting the Version 8 with the Neetronics controller. I heard you can make the ratio 10/90 with the Neetronics.....weeeeee dorifto in the rain....lol

I bet the diffs wouldn't like that 10/90 ratio though.

 

You cant do that. The physical starting point of the diff is 35/65. Any type of electronic action changes that from 35/65 to any variation between 35~50/65~50.

In order to make it do 10/90...that means you have to change the physical MECHANICALS inside the center diff.

 

Neetronics state otherwise....:dunno:

 

Yep 8500 rpms. Total cost of having Ron do the block and me doing the heads will be in the neighborhood of $4-5K. Not too shabby considering what it'll be capable of.

 

I wonder what kind of crack they are smoking.

 

JDMSpecC4U is a Neetronics dealer and I'd recommend dealing with them like I said in our last PM. They're kinda difficult to get in touch with since they just moved to the new shop but customer service is top notch.
Are you going to port out the stock heads or go with some JDM heads?

 

Port the stockers. Dunno what CR I'm going for on the block.

WJM what do you recommend? Stick STi gaskets in there for 9:1CR or try to get 8.3-8.5:1 CR? Which is better for reliability and longevity?

 

Never mind....it wasn't Neetronics....it was a tard on a video that was drifting around a corner....he just had it at 35/65 and with more power to the rear of course it was slinging it out. DuH. THat idiot said it was 10/90. I bet he was misreading it as the dc percentage or something.

 

thats still a LARGE debate. Everyone says higher compression for better spool and more power...but form what Ive seen, most of the powerful STi's (on moderate builds) make LOTS of power with rather low compression numbers (110~120 psi).

Dan's 04 STi had 100-100-90-100 psi on his crawford shoftblock with stock heads/cams and it made 616 wheel hp on a GT35R/Hydra/Race gas.

I really dont know, I've not done an extensive testing myself.

*HOWEVER*....the manufacture has done extensive. There MUST be a reason the stock STi has 8.2:1...

In that case, I would recommend staying in the 8.0:1 to 8.5:1 range.

 

That's what Ron recommended and that's what I most likely am going with. I'm just scared of the Cometic Headgaskets....I have had notoriously bad luck with them on my DSM but I'm willing to bet my head was warped.

 

I wish I can change the title to a little step backward in prep for a huge leap forward.

 

Cometics on SUBARU's are BBBBBBBBAAAAAAAAAAAAAAADDDDDDDDDDDDD!!!!!!!!!!!

and DO NOT use the ARP head studs.

The stock gaskets and bolts from SUBARU are KNOWN to hold 600+ hp at the wheels. ALL of our cars (except one) that make lots of power have stock gaskets and bolts. Only one car has ARP's but it has STOCK headgaskets.

 

Well what gaskets are you supposed to use to get the CR down? What gasket's were Dan's car using? I'm glad you told me about the ARP's....I have a used set in a box at home.

 

Done. I've heard nothing but bad things about cometic head gaskets on subarus. Are you going to put some big cams in there when you have the heads out for porting?

The theory with compression ratio is that if you run a lower compression ratio you can run more boost on the turbo to make the same power. With a higher CR you can run a turbo at less boost. Try to pair the CR and the target boost so that the turbo is in its efficiency range for the fuel you plan on using. Higher CR will give better off-boost response and lower CR will increase lag.

 

11044AA642 are stock for EJ257/255. It makes ~8.8:1 on the 205 heads and 257 block.

11044AA610 are stock for the EJ25D and are made the same way as the 642 (multi layer metal) and make the compression ~8.4:1 for the 205 heads on 257 block.

If you want to be dumb...use the 11044AA632. Thats the coated single layer metal gasket that leaks coolant (externally) after a few years for the 2.5 phase 2 SOHC engines (EJ251/253). It makes about 9.1:1 or so.

Cometics are a CHEAP knock off of the SUBARU gaskets.

 

I'm assuming that 11044AA610 (EJ25D) is what LiquidForce is using. Didn't he test the dumb theory and use 11044AA632 the first time? (No Mike I'm not calling you dumb just stating what WJM said).

 

I'm honestly surprised Siegel hasn't posted his thoughts on my plans. I talked to him yesterday but service sucked where I was and I could barely understand him.

 

yeah, mike used them. LOL

Id personally use the EJ25D's on modded 205 heads.

But...when the time comes...I'll be using 251 heads with cams and the 642 headgasket.

 

Wow this thread quickly became very informative.

 

Thanks GTScoob. Yes I'm putting in some 272 Crower cams I think.


I'm confused as to how to get the CR ratio to where I want it. Is there a simply calculation that can be done to get this magic number? I'd like to get around 8.5:1 as a happy medium. With 8.5:1 CR it should have better off boost response than a stock STi but then again no AVCS means a lot.

 

Use the 610's then.

 

Higher compression ratios increase the VE of the motor.

The new race motor for my car is going to be a 2.5 with 10.5 to 1 compression ratio running 27-32lbs of boost and nitrous.

I would go 9 to 1, for the most part the subaru tuning community is so far behind the curve it isn't even funny.

My Mustang Motor is 13.5 to 1 and if we decide to really go racing with it its getting a blower. Some of the big blower guys run huge compression numbers. Its all about octane.

9 to 1 is no problem on pump gas.

 

So the 642 would get me closer to 9:1CR. I dunno but I have plenty of time to do tons of research.

Does cams affect CR at all?

 

The cam effects dynamic compression ratio. SO you can run higher compression with bigger cams because at low rpms the cam bleeds off some compression ratio.

Matt

 

the 642's yeild 8.8:1

I would heavily advise AGAINST the 632's as they will inevitably start leaking coolant externally.

oh and cams affect dynamic compression and VE a good bit. However, static compression should be nearly the same...as whatever stock cams show for whatever setup you end up with. I've seen 160~180 psi from the 642 gaskets on 205 heads/257 block.

 

ooops...yeah, what matt said too. lol

 

You need to figure out what thickness gasket you need and then order it from Cometic.

Cometic gaskets work thats why everyone uses them.

 

I was one of the first people to do the swap and it was the first one I had done. I had called Ron at Axis and he said to use rs gaskets. I went to sog and bought the wrong ones. Nobody there new which ones were the right ones at the time.

I actually liked them much better than the ones I am running now and plan on going back to them the next time the heads come off. The cam timing is ever so slightly off with the thicker gaskets and off boost throttle response is not as good. I never had any issues with the gasket leaking and I ran 27 psi on a 20g daily. The block finally started having issues but that was after 50k miles of being pushed hard with the 632 headgaskets and stock pistons.

My compression was 180psi with the older rs gaskets and is now 170 with the new gaskets.

632 FTW (my blocks never make it 2 years so leakings not an issue )

 

I dont know about that....every single car I've seen has had them start leaking within 10k~20k miles after install. Slight oil mixture in coolant, random overheating....etc...even seen some that train wrecked up under the head and all the compression from a cyl went into the cooling system and blew up the radiator.

On top of that, SUBARU offers the same thickness gaskets for the same (if not cheaper depending on where you get them) price AND they are specifically designed for the engine....the 610 and 642 gaskets they certainly did NOT take any shortcuts on....

The highest mileage I've seen on a Cometic before failure was about 30k miles.

 

Well although I am looking to make power and rev the daylights out of this engine, I am also looking for decent spool and hold decent power up top. I think the SZ55 is up to the task but again I'm no tuner so Doug and SS can give better input.

My biggest requirement is that this be a reliable and long lasting engine.....I ask a lot but I'm willing to do the work, research and take the time to make sure it does so. If I'm asking a million questions I'm sorry but how else can I learn. There's so much mis-information that you just don't know what to believe.....hence all the questions.

Thanks so much for all your input guys and help. That's what makes WRXAtlanta what it is. Ok lets keep discussing this.....maybe someone else wants the same for their car

 

I was told that if I want to shoot for higher CR that it would be best to get rid of the Ecutek and go with a better stand alone like the Hydra.

Thoughts????

 

I would AEM over Hydra.

However, I'd try to stay with the stock ECU for as long as possible.

 

You have lost youre mind. Maybe the people putting them together don't know what they are doing.

I've ran them on 3 cars and never had a problem.

I know guys with 1000 plus horsepower mustangs and they all use them.

Its funny how it works on every car except a subaru.

Matt

 

Hmmmmm forget the GT52......I may just go Hydra. The hell with Ecutek....they jipped SS and me. Their customer service flat out SUCKS. I mean comeon $200 for a cable that costs maybe $40 at the most to make. I don't care if the license is in it.....that is poor design to begin with. Put the freaking license on the software like the others. And locking my ECU....grrrr I'm done with them.