"found out my EJ18 heads were nearly identicle to EJ22t

[ciper]

Posted by Kostamojen


quote: posted by Corkfish
I thought the valves are the same sodium filled ones on the STI. Car and Driver seemed to suggest that this was the same motor, but with smaller turbo, intercooler and ecu.

qoute: posted by Kostamojen
As far as I know, the XT doesnt have the sodium filled valves. Nowhere does it suggest it does. As for the cams, they might be slightly different... After I found out my EJ18 heads were nearly identicle to the EJ22T heads I did more research and found that the cams were identicle exept for a different elevation measurement, so its possible they are SLIGHTLY different to acount for different tuning.

[vrg3]

I'm not sure I understand.

Are you saying, with these quotes, that EJ18 heads are identical to EJ22T heads except that the cams have slightly different valve lift?

But EJ22T heads (passenger side ones anyway) have extra passages for oil and coolant, don't they? The EJ18 head wouldn't have that.

I thought the only differences between EJ22 and EJ22T heads (on BC/BFs anyway) were those two lines and the camshafts:

Non-turbo:
Intake valve opens at 4 deg BTDC, closes at 52 deg ABDC
Exhaust valve opens 48 deg BBDC, closes at 12 deg ATDC
Maximum lift on cam profile is 32.414 +/- 0.05mm (service limit 32.11mm)

Turbo:
Intake valve opens at 6 deg BTDC, closes at 52 deg ABDC
Exhaust valve opens at 42 deg BBDC, closes at 10 deg ATDC
Maximum lift on cam profile is 32.336 +/- 0.05mm (service limit 32.04mm)

Or are there also differences in the valves and valve springs?

[scottzg]

wouldnt n/a cams produce more power in a turbo engine than turbo cams? albeit it would be a peakier engine...

the forester doesnt have the valves because peak output is at a lower rpm and its not expected to be given the same workout an sti is. Correct me if im mistaken, but heat sink is a big problem with turbo motors, you wouldnt see it ordinarily, cause most people dont leave the gas on for more than 10 seconds (0-80 freeway onramp) and so the heat is not an issue. But many romps from 20-80-20 quickly (mountain driving) generates some serious heat that could cook your valves.

A turbo forrester is gonna see the 1st type of driving, the sti, the second.

[vrg3]

wouldnt n/a cams produce more power in a turbo engine than turbo cams? albeit it would be a peakier engine...

Why would that be the case? I don't understand camshaft tuning as well as I would like.

[evolutionmovement]

Both passenger and drivers side heads on the EJ22T appear identical. I'm pretty sure I could switch them around without issue.

Steve

[vrg3]

Both passenger and drivers side heads on the EJ22T appear identical. I'm pretty sure I could switch them around without issue.

But... the turbo oil and coolant lines!

The part numbers are the same for both sides on the non-turbo, but are different for the turbo.

[evolutionmovement]

Ah, yes. You would have to drill and tap a hole for the line near the block (the other is incorporated in a part attached to the head that when used on the other side provides the mounting for the extension on the driver's cam sprocket so they all line up for the timing belt) - looks like it might be pretty easy to tap that hole if for some reason you had to do it.

Steve

[Kostamojen]

I'm not sure I understand.

Are you saying, with these quotes, that EJ18 heads are identical to EJ22T heads except that the cams have slightly different valve lift?

But EJ22T heads (passenger side ones anyway) have extra passages for oil and coolant, don't they? The EJ18 head wouldn't have that.

Since I posted that, I did find that there were the extra coolant lines on the outside of the heads. However, this MAY be a swapable part with the EJ18 heads since the bolt patterns and probabbly the rest of the head internals will be simular. I might actually get a chance to get some EJ22T heads to try this out in the near future.

As for compairing the EJ22 and EJ22T heads and the EJ18 heads, yes the EJ22 needs to go in there as well, but ONLY the older model heads as they have changed quite a bit over the years. The valve springs appear to be identicle between the EJ18 and EJ22T from reading the stats I have, and the valves are the same dimensions but as for the actual part, I do not know. The accuracy of this guide is questionable too, but from what ive seen of the EJ22T and the EJ18 they are indeed very simular.

The camshafts really do seem to be the only major difference along with the extra coolant/oil lines, but I'm thinking about trying some swaping to see what will swap over.

[vrg3]

I'd believe that the early EJ22 heads, the EJ18 heads, and the EJ22T heads are all the same except for the coolant/oil lines and the camshafts. I mean, why would Subaru make them different? :)

Legos.

[Kostamojen]

I'd believe that the early EJ22 heads, the EJ18 heads, and the EJ22T heads are all the same except for the coolant/oil lines and the camshafts. I mean, why would Subaru make them different?

Legos.

Thats what im thinking.

[THAWA]

I'll have to concur, I was examing the heads on mine and it looked like everything was the same except backwards (because of them being on opposite sides), the mounting of the camsensor on the driverside, and that the driversside has the oil filler neck in the valve body.

[evolutionmovement]

That's what I'm saying - the only difference in the EJ22T is whether or not the hole for the lower coolant/oil line is drilled and tapped. The surface in that area is even already machined. The other line is an add-on fixture. I would even bet the EJ22 N/A heads are the same as the T's driver's side. Would sure help reduce the cost of manufacturing an inherently more expensive motor as there would only really have to be one assembly line for all the heads just working double time against the block foundary.

Steve

[Legacy777]

The whole turbo vs. non-turbo cam timing thing......I'm sure you could swap cams, but it probably wouldn't produce the best results.

However by those specs posted. The amount of valve overlap is the same between turbo & n/a. It's just when it takes place. I can see why they did it though. The turbo cars will have a positive intake pressure to help scavenge the cylinder, so they can open the intake valve sooner and not have to rely solely on the piston creating a vacuum to pull the air/fuel mix in. Since this is the case, the exhaust valve can be closed sooner too, since scavenging took place sooner.

You can use the same reasoning on the opening of the exhaust valve. The n/a cars have the valve open sooner because it doesn't have forced air coming in to cool & scavenge the cylinder. Also, you might be able to say that with the exhaust valve opening sooner, your exhaust pulses will have a higher amplitude and longer wavelength.

Those cams really look kind of blah actually.....

[camshaftprelube]

wouldn't a wider lobe displacement angle help a turbo motor? I mean, you don't want valve overlap, and you want the exhaust valves open for at least as long as stock, so the gases would have time to enter the turbo.

[Kostamojen]

So are you guys saying the EJ22 Turbo cams are not going to be useful at all?

[Legacy777]

I don't know if I'd say it wouldn't be useful, they just may not be the best. Like I said, the turbo legacy cams look very meek for a turbo cam profile. Look at the amount of overlap....personally I would think you'd want less.....but what do I know...right... it's probably setup that way since the car was not a high boost car.

I'd be curious to see what the cam profile info is for the EJ18's & the WRX motor

[boostjunkie]

I'd be curious to see what the cam profile info is for the EJ18's & the WRX motor

Let me take a look at 21st Century Performance when i get home. I know they had listings for various stock cam profiles in it, and the wrx was one of them.

[greg donovan]

I'd be curious to see what the cam profile info is for the EJ18's & the WRX motor

Let me take a look at 21st Century Performance when i get home. I know they had listings for various stock cam profiles in it, and the wrx was one of them.

what happened w/this research?

thinking hotter cams might be a good idea but not sure how "hot" i can go before i need better springs and retainers as well as ecu upgrades.

i know im building N/A motor but this is the best camshaft thread i have found thanks to vrg3 and his creepy memory.

[tris91ricer]

mm.. so you're all saying that putting the majority of the turbo engine parts on an NA block, sans turbo, with smaller displacement heads, that you'd get a stronger engine? A friend of mine tried something similar(head swap) if understand this correctly, he put 1.8 heads on his 2.0L civic, resulting in higher compression --is that right? is that what you're all trying to do? I don't even understand really what the cam does, but i'd be happy to learn.. does higher compression equal more power in some way? But why would we go with a 2.5head swap as opposed to a 1.8? would that make it bigger displacement, as opposed to higher compression? I'm VERY unclear in this area, and i'm just guessing out my ass... vikash? could you ring in on this one? And i'd be happy to find the wrx cam profiles, or whatever it is you guys want out of that..
What happens with 'hot' cams? how does it affect the springs and retainers?
best,
-=tristan

[scottzg]

http://auto.howstuffworks.com/engine.htm

[greg donovan]

reducing the combustion chamber will raise the CR and make a bigger bang which makes more power. increasint the combustion chamber will lower the cr making less bang and therefore less power. in a turbo application this would be good because than you can increase boost more and safely make an even bigger bang and therefore get even more power.

cams change how long and how far the valves open and close. this is where i fall short on knowledge too. i know what is good but not the why.

[evolutionmovement]

It depends on what you're looking for. Overlap in general is better for N/A at higher rpm while with a turbo you want less or no overlap (intake and exhaust open att the same time) as you'll lose boost. Lower engine speeds also require different cam profiles than higher speeds due to difference in airfloe characteristics. This can also be matched to intake design (longer runners for lower rpm as intake pulse scavenging takes longre at lower rpm than at high, necessitating longer runners to time the pulse to the intake charge for the open cylinder).

Steve

[tris91ricer]

This can also be matched to intake design

This similar to the dual intake runners on the SHO? I've heard about that in similar intake threads.. hmm.. thought provoking..
what kind of info is needed for the cam profiles? is this something as simple as calling the parts counter? I found a small table somewhere that gave me specs on the wrx cam, but nothing i could make use of.. didn't know if it was what you folks were interested in..

happy labor day,
-=tristan

[evolutionmovement]

Do you mean profiles of off-the-shelf cams or custom profiles you spec? A good preformance shop should have the info on standard upgraded cams, but not for our cars and the dealer's or auto parts places will likeley be clueless as hell on the profiles of OEM cams.

If you mean designing your own, forget it. It requires way too much data gathering and engineering to develop cams on your own. I know a little about this stuff - enough to know I don't know enough to come up with my own profiles. If you know what you're doing you could maybe make small adjustments to standard cam specs for slightly better power in a certain range, but the effect on emissions and the requirement for tuning for questionable and likely minor effect wouldn't be worth it. I think the best and cheapest solution would be to find cams that someone else has developed, be they OEMs or aftermarket and better yet if someone else has tried them first and you can get their opinion.

The turbo and N/A cams are slightly different, but the effect on power seems entirely negligible compared to the compression difference.

And yes - variable length intakes (and exhaust, too - same principle backwards) are used to adjust length to optimize for diffent rpm ranges using scavenging principles. I don't know if that makes sense, but if you need further explanation, I could give you some.

Steve

[stipro]

Although the heads may seem the same in size and basic shape they are different because for one the use 8 bolts to hold them on, and they also use cam boxes bolted to the head.