liberty engines

teaguespeed · Post by **teaguespeed** » Mon Feb 10, 2003 3:42 am

why did the libery rs engines have so much more power than our legacys?

Mark Ward · Post by **Mark Ward** » Mon Feb 10, 2003 4:29 am

To start...
DOHC, different mapping, better flowing heads
Mark

vrg3 · Post by **vrg3** » Mon Feb 10, 2003 5:41 am

...Air-water intercooling...

vypa · Post by **vypa** » Mon Feb 10, 2003 7:28 am

im curious... is there a way to switch our engines over to DOHC? (ie diff heads thatll fit)

IggDawg · Post by **IggDawg** » Mon Feb 10, 2003 2:04 pm

With some work I'm pretty sure you can use DOHC heads from a pre-99 EJ25. I gather the water passages need some work and there's a small issue with there being a slight difference in the bore of the head and the piston (larger on the head) but neither of these things present a major challenge. I've heard this setup is good for some huge numbers. well beyond the ~350hp limit of the pistons. The EJ22 is a monster if you get it to breathe right.

Post by **Legacy777** » Mon Feb 10, 2003 6:01 pm

The EJ25 heads will decrease the overall compression ratio on the EJ22.

Here's some threads to check out

http://forums.nasioc.com/forums/showthr ... EJ22+heads

http://forums.nasioc.com/forums/showthr ... did=292519

http://forums.nasioc.com/forums/showthr ... alve+sizes

IggDawg · Post by **IggDawg** » Mon Feb 10, 2003 6:27 pm

If one was so motivated to do this sort of swap, you could assume they were in it for high numbers. If they used super-strong 8.5:1 pistons, they'd still end up with a CR more than they started with. not 8.5:1, but still better than 8:1. not that there's anythign wrong with 8:1

.

I certainly don't think I'll ever go this route, but I'd lvoe to hear the stories of those that have. I'll be happy with 230hp. that's my goal, and I think I can do it without new heads.

boostjunkie · Post by **boostjunkie** » Mon Feb 10, 2003 9:12 pm

I do have a set of DOHC heads from my busted engine. However, I've also heard stories of the combination dropping CR to 7.7 to 1. Now is there a way to mill the heads down to increase the ratio? I know there are limitations to how much you can shave off the heads, but will those limitations be affected by the different pistons in the turbo block?

IggDawg · Post by **IggDawg** » Mon Feb 10, 2003 10:07 pm

I'd say just swap the pistons. is that a drop from 8.0 to 7.7, or 8.5 to 7.7?

Also, if you mill down the heads too much it can screw with timing IIRC. less distance the belt has to travel. At some point the tensioner pulley runs out of play. I don't know how far that is, tho. also, air passages can get "crimped" if you shave off enough that smooth curves get cut a little short so you have passages that meet improperly.

All this is speculation. I'm just visualizing.

boostjunkie · Post by **boostjunkie** » Mon Feb 10, 2003 10:11 pm

IggDawg wrote:I'd say just swap the pistons. is that a drop from 8.0 to 7.7, or 8.5 to 7.7?

Also, if you mill down the heads too much it can screw with timing IIRC. less distance the belt has to travel. At some point the tensioner pulley runs out of play. I don't know how far that is, tho. also, air passages can get "crimped" if you shave off enough that smooth curves get cut a little short so you have passages that meet improperly.

All this is speculation. I'm just visualizing.

It's a drop from 8.0 to 7.7 . . . using the DOHC heads and the turbo block. As for pistons, I thought the that cylinder widths were different?

IggDawg · Post by **IggDawg** » Mon Feb 10, 2003 11:51 pm

I mean getting aftermarket 8.5:1 pistons. I'm pretty sure someone makes them. I'm figuring if someone needs the extra breathing of the 2.5L heads, they're prolly gonna need new pistons at that point too. I could be wrong tho. happend once bafore back in '82.

Mark Ward · Post by **Mark Ward** » Tue Feb 11, 2003 1:03 am

Does anyone know of the EJ20T heads will fir the 2.2 bottom? I happen to have the heads etc from my old motor sitting in the shop...
Mark

boostjunkie · Post by **boostjunkie** » Tue Feb 11, 2003 3:26 am

If they're the same design as the new WRX heads then they'll work. Better yet, as people have noted with the USDM wrx heads, you'll be able to keep the 8 to 1 compression ratio!!

You lucky bastard!!

boostjunkie · Post by **boostjunkie** » Tue Feb 11, 2003 3:27 am

FWIW, the Liberty RS heads flow better than the wrx heads.

Post by **Legacy777** » Tue Feb 11, 2003 4:04 am

Here's some more reading guys

http://www.xmission.com/~dac/library/headswap.htm

vypa · Post by **vypa** » Tue Feb 11, 2003 5:02 am

so it seems more likely that it might bolt right up to the N/As with a bit of work? and the cams should be ok... right?

Mark Ward · Post by **Mark Ward** » Tue Feb 11, 2003 5:44 am

So...
What would they be worth?

They use the 2.5 timing belt...

Mark

boostjunkie · Post by **boostjunkie** » Tue Feb 11, 2003 2:04 pm

Legacy777 wrote:Here's some more reading guys

http://www.xmission.com/~dac/library/headswap.htm

Legacy777, I've read that writeup before (it's on DLC's website, correct?). Anyways, I think that only pertains to the 2.5L heads, and not the wrx heads. I could be wrong, though.

Post by **Legacy777** » Tue Feb 11, 2003 2:50 pm

Yeah it pertains to the 2.5 heads.........were you guys talking about the 2.0 heads??

Guess I missed that......

boostjunkie · Post by **boostjunkie** » Tue Feb 11, 2003 3:02 pm

We started talking about the 2.5L heads, but then someone posted that they had wrx heads . . . *shrug*

vypa · Post by **vypa** » Tue Feb 11, 2003 5:15 pm

also... what about the heads from the new WRX STI? the 2.5 turbo... would those heads maybe be a good option for those of you that have the EJ22T?

IggDawg · Post by **IggDawg** » Tue Feb 11, 2003 5:45 pm

Those are AVCS heads. without an AVCS capable ECU, they might get a little weird I presume.

vypa · Post by **vypa** » Tue Feb 11, 2003 5:48 pm

i forgot about that igg

good point

Mudpup · Post by **Mudpup** » Wed Feb 12, 2003 1:40 am

Anyone know specifics on the control signal(s) for AVCS, ie. could it be controlled with a GPO from Tec II/Tec III? Or even some home grown control ckt?

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