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Old 06-18-2009, 06:41 PM   #1
waldo
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Default the great debate built ej207 or built hybrid?

please enlighten me with some of your insight... so i live in MA and i would love to just put a v8 swap in my MY04 and be done with it but i need a obd2 compliant engine, so Ive been thinking of either building up a 207 w/ tomei stroker kit, 20g or a tomei arms turbo, pnp'd v8 heads, meth, and the like. i would like an engine thats smooth higher up in the rpm band and Ive heard the 257 is a little rough... BUT then again the 257 is quite torque happy and Ive heard some good things about building a 257/207 hybrid. again the hybrid would also have a built bottom end with the same turbo choices. just help me decide and maybe give me some insight from both sides
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Old 06-18-2009, 06:49 PM   #2
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the V8 is OBD II compliant. but your much better off with a V7 engine (better internals). it is also OBDII compliant.
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Old 06-18-2009, 06:56 PM   #3
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not OBDII compliant in the sense that you can only put a motor of the same year or NEWER from the same make that came in the car. atleast thats how it is in california and new york.
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Old 06-18-2009, 07:24 PM   #4
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welding hank thanks for the good news maybe i should talk this over with ecs.... but in the mean time the tomei parts at dsg have caught my eye.

also i may have posted this in the wrong forum can somebody move this to the built motor section??
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Old 06-18-2009, 08:46 PM   #5
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Originally Posted by Alex_Kors View Post
not OBDII compliant in the sense that you can only put a motor of the same year or NEWER from the same make that came in the car. atleast thats how it is in california and new york.
technicaly the same in ma. but for the most part, an inspector is just gonna check your lights,tires,front end and that the OBD scans ready.
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Old 06-19-2009, 03:05 AM   #6
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technicaly the same in ma. but for the most part, an inspector is just gonna check your lights,tires,front end and that the OBD scans ready.
ah, yeah you guys have it easy! you'll never pass a ref in NY or CA like that.
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Old 06-19-2009, 11:46 AM   #7
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I'm having a great time with my 205/257 hybrid. I don't do any track days or drag racing but the added torque makes daily driving a blast. When I had a 205 with an 18G, I saw peak torque at 4000. With the hybrid, I see peak torque at 3800 with an FP Green. Now I don't have to down shift anymore to pass on the freeway and I don't even get into boost around town.
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Old 06-19-2009, 01:22 PM   #8
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anybody with some built 2.0L experiance wanna chim in?
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Old 06-19-2009, 01:35 PM   #9
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Sounds like a 2.12L stroker would be a good option for you. EJ257 crank, longer rods and very lightweight pistons. The shorter rod ratio would help decrease lag while the light reciprocating mass and small bore help keep the higher RPM's 'smoother and with less needed timing, respectively.

If you opted for a higher CR piston, that would further help the low end torque (as does the shorter rod ratio).
You can build it with the block you already have or a used EJ205 which sells cheap now anyhow.

You can just build some low EJ205 heads too (they sell cheaply used), that is unless you really want AVCS.
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Old 06-20-2009, 06:39 AM   #10
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Quote:
Originally Posted by 3MI Racing View Post
The shorter rod ratio would help decrease lag
Do you mean lower r/s ratio? Are you saying that a lower r/s ratio will give the piston more dwell time at TDC so you get a more complete burn etc which helps with power so you get more spool? ehhh if so i think thats such a marginal difference its not even worth thinking about, i have seen identical motors built with just varying r/s ratio's and while there was a difference it was marginal, i mean like 5-7whp and unless your building an NA honda 5-7whp is nothing to think about. If i am seeing any of this wrong please fill me in, i am kind of new to subies but not to cars/engines/theory etc..
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Old 06-20-2009, 12:39 PM   #11
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Quote:
Originally Posted by waldo View Post
please enlighten me with some of your insight... so i live in MA and i would love to just put a v8 swap in my MY04 and be done with it but i need a obd2 compliant engine, so Ive been thinking of either building up a 207 w/ tomei stroker kit, 20g or a tomei arms turbo, pnp'd v8 heads, meth, and the like. i would like an engine thats smooth higher up in the rpm band and Ive heard the 257 is a little rough... BUT then again the 257 is quite torque happy and Ive heard some good things about building a 257/207 hybrid. again the hybrid would also have a built bottom end with the same turbo choices. just help me decide and maybe give me some insight from both sides
Even though I have most of the Tomei parts (cams, turbo, header/uppipe, gaskets, timing belt guide, and oil pan baffle ), there's way more cost effective ways to stroke a 207. Talk to the vendors around here, get a nice combo like an STi crank, Pauter rods, and Wiseco pistons. I'd do that.

I have a built 257 hybrid with V7 Spec C heads (just the same as the V8 big ports), that Tomei ARMS turbo, and a lot of supporting mods. I'm very happy with this setup. Full spool around 3200RPM and power through redline, responsive on pump gas, and incredible on 100 octane. Do you want low RPM power or mid/top end? The two motors will be very different. Mine, with all the torque (392 on a Mustang dyno ), and short JDM gearing feels almost violent, whereas the 207 will feel smoother and more gradual.

Quote:
Originally Posted by slowmike View Post
I'm having a great time with my 205/257 hybrid. I don't do any track days or drag racing but the added torque makes daily driving a blast. When I had a 205 with an 18G, I saw peak torque at 4000. With the hybrid, I see peak torque at 3800 with an FP Green. Now I don't have to down shift anymore to pass on the freeway and I don't even get into boost around town.
I don't have to downshift anymore either.

Quote:
Originally Posted by 3MI Racing View Post
Sounds like a 2.12L stroker would be a good option for you. EJ257 crank, longer rods and very lightweight pistons. The shorter rod ratio would help decrease lag while the light reciprocating mass and small bore help keep the higher RPM's 'smoother and with less needed timing, respectively.

If you opted for a higher CR piston, that would further help the low end torque (as does the shorter rod ratio).
You can build it with the block you already have or a used EJ205 which sells cheap now anyhow.

You can just build some low EJ205 heads too (they sell cheaply used), that is unless you really want AVCS.
+1 for higher compression. I'm running 8.8:1 and I think that's what makes the car so responsive and torquey...not to mention fun.

Quote:
Originally Posted by GundamFan View Post
Do you mean lower r/s ratio? Are you saying that a lower r/s ratio will give the piston more dwell time at TDC so you get a more complete burn etc which helps with power so you get more spool? ehhh if so i think thats such a marginal difference its not even worth thinking about, i have seen identical motors built with just varying r/s ratio's and while there was a difference it was marginal, i mean like 5-7whp and unless your building an NA honda 5-7whp is nothing to think about. If i am seeing any of this wrong please fill me in, i am kind of new to subies but not to cars/engines/theory etc..
Just easier/better for the motor to rev, especially for long intervals, if the r/s ratio is in spec.
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Old 06-21-2009, 02:40 PM   #12
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Quote:
Originally Posted by zeropsi View Post
Even though I have most of the Tomei parts (cams, turbo, header/uppipe, gaskets, timing belt guide, and oil pan baffle ), there's way more cost effective ways to stroke a 207. Talk to the vendors around here, get a nice combo like an STi crank, Pauter rods, and Wiseco pistons. I'd do that.

I have a built 257 hybrid with V7 Spec C heads (just the same as the V8 big ports), that Tomei ARMS turbo, and a lot of supporting mods. I'm very happy with this setup. Full spool around 3200RPM and power through redline, responsive on pump gas, and incredible on 100 octane. Do you want low RPM power or mid/top end? The two motors will be very different. Mine, with all the torque (392 on a Mustang dyno ), and short JDM gearing feels almost violent, whereas the 207 will feel smoother and more gradual
i would like a very responsive engine that builds boost around 3200 and holds it till redline.. maybe 20-21psi.. i would aslo like my engine to be high rpm friendly like ive heard the v7 is. id like torque aswell but i dont need a torque monster, and ive heard some bad things about the 257's bore and stroke... i do like 3MI's 2.12 stroker idea and im waiting for them to price this out for me
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Old 06-21-2009, 02:51 PM   #13
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The only two real 'bad' things about the 257's bore and stroke are the rod/stroke ratio (which makes the 257 a little less happy at high RPM's compared to a 207), and the bore - stock it's not bad, but it doesn't leave a whole lot of cylinder wall left, especially if you go any bigger bore.

Do you mean starts building boost by 3200 or hits full boost @ 3200?
You wouldn't find a 207 that builds boost @ 3200 and holds until redline. A 5K powerband would be pretty much impossible with that kind of spool. It would be a bit easier with that stroker.

I must say though, my 257 hybrid, is a very responsive engine, that in fact hits full boost right around 3200, and holds it all the way through redline. My redline is set pretty low for a built motor @ 7200. So that's 4000RPM of power right there. I'm sure that stroker wouldn't be too far off.
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Old 06-21-2009, 03:48 PM   #14
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Go 2.35 closed deck , It's almost a perfectly "square" motor spins like no tomorrow . FTMFW!
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Old 06-21-2009, 05:45 PM   #15
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While square motors seem to be it for inline configurations, I'm still undecided whether or not I think the same advantages apply to horizontally opposed motors. Larger bore than stroke seems to be working so far.
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Old 06-21-2009, 08:34 PM   #16
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Quote:
Originally Posted by sense of nature View Post
Go 2.35 closed deck , It's almost a perfectly "square" motor spins like no tomorrow . FTMFW!
Just need to pick you up on this.



First, do you know what square it? For an engine to be classed as "square" it requires a bore to stroke ratio of 1 - and I am yet to see any EJ engine come close to being square.

So for a 2.35L:

79mm x 97.5mm = 2.359L = bore:stroke of 1.234 = not square
75mm x 99.5mm = 2.332L = bore:stroke of 1.326 = not square

And stock:
79mm x 99.5mm = 2.457L = bore:stroke of 1.259 = not square
75mm x 92mm = 1.994L = bore:stroke of 1.226 = not square

And really oversquare :P:
75mm x 103mm = 2.499L = bore:stroke of 1.373 = not square




Second, it isn't "square" motors that like to "spin" (not saying they can't), but rather oversquare engines.

Basically they can "spin" quicker due to their shorter stroke and while doing so, they place less load on bearings and rotating assembly at any given rpm compared to engines that are "square" or undersquare.

This is why F1 engines are hugely oversquare

In reality though, it isn't as simple because manufacturers design their engines to survive upto a specific rpm and a very specific use. Once you go outside this many things can and do go wrong unless you spend the time and money developing your engine to suit its new purpose.

Leslie.
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Old 06-21-2009, 08:50 PM   #17
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Quote:
Originally Posted by zeropsi View Post
While square motors seem to be it for inline configurations, I'm still undecided whether or not I think the same advantages apply to horizontally opposed motors. Larger bore than stroke seems to be working so far.
i thought it was rod to stroke ratio? i know F1's have higher rod stroke ratio, some 2-1 or higher as to where the subaru is like 1.7 or so, with a bigger piston it can still spin but has to deal with the extra weight of say a 4inch piston. now a stock 2 liter, or a 2.3, destroked 2.5 liter it will have a better rod to stroke ratio, and a still rather light piston, which would be better that an a 2.2 to a 2.3 with a 79mm crank., longer rod to stroke ratio helps to lower side loading of the piston against the cylinder walls
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Old 06-21-2009, 09:51 PM   #18
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Quote:
Originally Posted by seanathanq83 View Post
i thought it was rod to stroke ratio? i know F1's have higher rod stroke ratio, some 2-1 or higher as to where the subaru is like 1.7 or so, with a bigger piston it can still spin but has to deal with the extra weight of say a 4inch piston. now a stock 2 liter, or a 2.3, destroked 2.5 liter it will have a better rod to stroke ratio, and a still rather light piston, which would be better that an a 2.2 to a 2.3 with a 79mm crank., longer rod to stroke ratio helps to lower side loading of the piston against the cylinder walls
When talking about "square" engines, it is the bore to stroke ratio that is used. rod ratio is another thing altogther, but it too is an important ratio on its own.

Basically, the shorter the rod the more load that is placed on the crank and cylinder walls. But, eith shorter rod you have higher cylinder pressure and more torque.

EDIT: As with everything when it comes to engines, there is a tradeoff and in the real world it costs to much in R&D what is perfect, so the best you can hope for is basically improving your current setup with the strongest, lightest internals you can afford


Leslie.

Last edited by wrxsti.l; 06-21-2009 at 09:58 PM.
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Old 06-21-2009, 11:43 PM   #19
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Quote:
Originally Posted by seanathanq83 View Post
i thought it was rod to stroke ratio? i know F1's have higher rod stroke ratio, some 2-1 or higher as to where the subaru is like 1.7 or so, with a bigger piston it can still spin but has to deal with the extra weight of say a 4inch piston. now a stock 2 liter, or a 2.3, destroked 2.5 liter it will have a better rod to stroke ratio, and a still rather light piston, which would be better that an a 2.2 to a 2.3 with a 79mm crank., longer rod to stroke ratio helps to lower side loading of the piston against the cylinder walls
Yeah, I'm not even taking that into account right now. My point is that while inline 4 cylinders (4G63, SR20, etc.) seem to be awesome and make good power at any RPM with square or close to square configurations, I'm not convinced that horizontal motors share the same dynamics, wherein that would be as much of an advantage. That said, I come from a V motor background where oversquare is king.

Quote:
Originally Posted by wrxsti.l View Post
When talking about "square" engines, it is the bore to stroke ratio that is used. rod ratio is another thing altogther, but it too is an important ratio on its own.

Basically, the shorter the rod the more load that is placed on the crank and cylinder walls. But, eith shorter rod you have higher cylinder pressure and more torque.

EDIT: As with everything when it comes to engines, there is a tradeoff and in the real world it costs to much in R&D what is perfect, so the best you can hope for is basically improving your current setup with the strongest, lightest internals you can afford


Leslie.
Everything's a trade off. I agree.

As far as square motors, a Subaru won't get totally square but people seem to want to get them close. I'm just happy with my junk USDM 2.5.
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Old 06-22-2009, 12:36 AM   #20
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It's an opposed "boxer motor " can't get any more squared than that ?
Yea I thought it was about rod & stroke relations Guess I need to read some more Nasioc Misinformation
thanks for clearing that up
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Old 06-30-2009, 11:10 PM   #21
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SO are we done here?
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Old 07-01-2009, 12:12 AM   #22
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Quote:
Originally Posted by 3MI Racing View Post
Sounds like a 2.12L stroker would be a good option for you. EJ257 crank, longer rods and very lightweight pistons. The shorter rod ratio would help decrease lag while the light reciprocating mass and small bore help keep the higher RPM's 'smoother and with less needed timing, respectively.
Micah,

Wouldn't it be better to keep stroke and rod length the same as EJ207 and just use oversized pistons? You "only" need 95mm pistons to reach 2.12L. You could always go stock stroke and +2mm rods with custom oversized pistons to suit if you wanted to improve rod ratio.

Saying that, if you were considering running 95mm pistons in an EJ207, you'll be needing sleeves anyhoo, and if you are going to run sleeves, you might as well get some AEBS sleeves and run a min 100mm pistons instead for 2.35L.


What are your thoughts mate - which 2.12L would you prefer and why:
2.12L with 79mm stroke + 92.5mm pistons + +2mm rods
2.12L with 75mm stroke + 95mm pistons + +2mm rods


Also, which of the following would you prefer and why:
2.45L EJ257 with 79mm stroke + 99.5mm pistons + stock sized rods
2.42L EJ207 with 75mm stroke + 101.5mm pistons + stock sized rods


Leslie.
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