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Old 03-03-2010, 10:24 AM   #26
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Originally Posted by deezel_d View Post
i am a noob here but trying to do a hybrid i have a built 257 and a complete ej20k that i was gonna use the heads off of.....do i have to do same thing with these heads..
You don't have to.

However, unless this is the last power mod you're ever going to do to your car, you want to. Gains are to be had across the entire RPM range. Basically anywhere fuel octane is limiting your ability to make power, this service will provide gains over your stock head configuration. Pretty much everyone tuning cars with ej205 heads on ej25x blocks has noted there are detonation issues at lower power than with proper heads on the same block.

As Ed noted "modifying the combustion chamber is not a new idea, but the CNC program is really helping to keep things consistent and precise." It's not a new thing, where the gains are questionable. There are known power gains to be had. The new thing is a CNC program to ensure all four chambers are very similar. Previously this would have been done by hand and there would be variation between the 4 combustion chambers.

Consider it like you would any other mod. You're spending whatever this costs plus shipping for like 5% power EVERYWHERE. (5% is completely made up, I have no idea exactly how much power it gains from tuning by raising the detonation threshold, Ed can probably give some insight on that).

The point is that normally you'd pay a similar price for any given bolt on. However, these usually only affect certain areas of the RPM band. Uppipe helps low, header helps high, etc... This is across the board, every RPM. Some mods, like a larger turbo, gain in one area and hurt performance in other areas, this gains everywhere. Once you're out of bolt-ons this still offers significant gains.

It is only something that is inexpensive if the heads are off. It's not like a turbo or header or whatever, where you can just swap it out later in your garage. So unless you're on a major budget, you probably want heads machined so that the diameter at the head gasket approximately matches the bore diameter.

I don't know the shape of those particular heads, they might be different enough to be incompatible with the CNC program, but a "hand job" on your combustion chambers would still offer significant gains over any head design that is built around an ej20 bore size.
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Last edited by Concillian; 03-03-2010 at 10:36 AM.
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Old 03-03-2010, 12:06 PM   #27
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Originally Posted by scby rex View Post
Good price, but this isnt anything new.
Like I said, the idea is not new, but I have never seen anyone map out the STI combustion chamber and create a CNC program to accurately and consistently reproduce it in every cylinder, every time.

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Old 03-03-2010, 12:08 PM   #28
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Why not design the machining process to mimic the ej207 heads? Those are after all the most efficient best flowing heads Subaru produces no?
The EJ207 heads have larger ports. The ports are not touched in this process. The main goal is to modify the combustion chamber to get the appropriate bore and volume the match the characteristics of an EJ257 shortblock.

Thanks
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Old 03-03-2010, 12:08 PM   #29
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Originally Posted by Concillian View Post
You don't have to.

However, unless this is the last power mod you're ever going to do to your car, you want to. Gains are to be had across the entire RPM range. Basically anywhere fuel octane is limiting your ability to make power, this service will provide gains over your stock head configuration. Pretty much everyone tuning cars with ej205 heads on ej25x blocks has noted there are detonation issues at lower power than with proper heads on the same block.

As Ed noted "modifying the combustion chamber is not a new idea, but the CNC program is really helping to keep things consistent and precise." It's not a new thing, where the gains are questionable. There are known power gains to be had. The new thing is a CNC program to ensure all four chambers are very similar. Previously this would have been done by hand and there would be variation between the 4 combustion chambers.

Consider it like you would any other mod. You're spending whatever this costs plus shipping for like 5% power EVERYWHERE. (5% is completely made up, I have no idea exactly how much power it gains from tuning by raising the detonation threshold, Ed can probably give some insight on that).

The point is that normally you'd pay a similar price for any given bolt on. However, these usually only affect certain areas of the RPM band. Uppipe helps low, header helps high, etc... This is across the board, every RPM. Some mods, like a larger turbo, gain in one area and hurt performance in other areas, this gains everywhere. Once you're out of bolt-ons this still offers significant gains.

It is only something that is inexpensive if the heads are off. It's not like a turbo or header or whatever, where you can just swap it out later in your garage. So unless you're on a major budget, you probably want heads machined so that the diameter at the head gasket approximately matches the bore diameter.

I don't know the shape of those particular heads, they might be different enough to be incompatible with the CNC program, but a "hand job" on your combustion chambers would still offer significant gains over any head design that is built around an ej20 bore size.
Excellent response!
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Old 03-03-2010, 02:13 PM   #30
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Originally Posted by Equilibrium Tuning View Post
The EJ207 heads have larger ports. The ports are not touched in this process. The main goal is to modify the combustion chamber to get the appropriate bore and volume the match the characteristics of an EJ257 shortblock.

Thanks
-- Ed
do you offer flowing the heads as an option? in other words, x dollars for the combustion chamber CNC process and x dollars for flow the ej205 heads?
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Old 03-04-2010, 01:29 AM   #31
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I'm sure many questions will be asked here, but first of all, very good idea to offer this service. I know others have done similar stuff of block/head matching, but I dunno any vendor that offers this job the way you do it, along with the maps you have made from all your experience doing it, etc. etc.

I think the questions here are going to be:

-How much, on top of the already stated price, will it be to dis-assemble and assemble the heads.

-Pricing should be given for heads sent in as blanks or sent in assembled.

-Any options like head porting and if so, cost to do this?

-Any options to upgrade the valvetrain or go shimless and cost to do so?


Maybe a consideration in all of this, to keep costs down, is to consider buying as many solid working heads, machine them out, and offer a trade in program for the customer where they send in their heads in proper working condition and get back your machined out heads. This eliminates turnaround time, takes money off the final price for the customer, and provides you with a set of heads to work on for your next customer wanting to have the same thing done to their heads (same idea as sending in your injectors to DW to have them modded and they take off $100 or $150 and send you back modded injectors).

Great offering and good luck!!!
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Old 03-04-2010, 06:21 AM   #32
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Well crap has to be for the 205 and it has to be in the states AND the price is good


DAMN YOU JDM LAND
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Old 03-04-2010, 06:47 AM   #33
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Originally Posted by Audioexcels View Post
I'm sure many questions will be asked here, but first of all, very good idea to offer this service. I know others have done similar stuff of block/head matching, but I dunno any vendor that offers this job the way you do it, along with the maps you have made from all your experience doing it, etc. etc.

I think the questions here are going to be:

-How much, on top of the already stated price, will it be to dis-assemble and assemble the heads.

-Pricing should be given for heads sent in as blanks or sent in assembled.

-Any options like head porting and if so, cost to do this?

-Any options to upgrade the valvetrain or go shimless and cost to do so?


Maybe a consideration in all of this, to keep costs down, is to consider buying as many solid working heads, machine them out, and offer a trade in program for the customer where they send in their heads in proper working condition and get back your machined out heads. This eliminates turnaround time, takes money off the final price for the customer, and provides you with a set of heads to work on for your next customer wanting to have the same thing done to their heads (same idea as sending in your injectors to DW to have them modded and they take off $100 or $150 and send you back modded injectors).

Great offering and good luck!!!
might as well go ahead and ask the final question. cam installation and shim dial in..

so prices:

1. cnc ports (heads arrived disassembled)
2. cnc ports and rebuild heads with new parts (heads arrived disassembled)
3. cnc ports, rebuild heads with appropriate parts (heads arrive intact, require tear down, buy some parts, such as valves can be reused)
4. add flowing head as option
5. add cam installation and setup as an option.
6. offer cam packages (shop supplies cams instead of customer).

i can think of more options such as upgraded springs, retainers etc..
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Old 03-04-2010, 03:16 PM   #34
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do you offer flowing the heads as an option? in other words, x dollars for the combustion chamber CNC process and x dollars for flow the ej205 heads?
Sorry we don't offer any flow testing right now. We do flow testing for our R&D work but we use a shop that's relatively far away, so it would make it difficult to work that in as a service.

Thanks
-- Ed
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Old 03-04-2010, 03:48 PM   #35
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Getting the chambers cnc'd out is a good idea... I have a hybrid 2.5l sb with the 2.0 heads, I tune it too. Another main problem no body has mentioned is pre ignition , when your air fuel mixture lights when you don't want it too ... With these hybrids the edge of the 2.0 head that hangs over the 2.5 block gets hot and lights the mixture before the sparkplug gets to... This can lead to catostrophic engine failure btw... No good!

I just took a look at some Subaru 2.0 heads in person that were CNC'd by Chimera performance .... I wasn't even thinking about getting my chambers cnc'd or heads ported because I have it tuned really good and have been making pretty good power, but after I got to see a stock subaru 2.0 head and the chimera Cnc'd head side by side I would say the Subaru stock head leaves alot to be desired for super even flow. Visually I could tell the ports/chambers were identical on the CNC'd head, really crazy how good these cnc machines can port/machine this stuff out identical... After I seen that it got me thinking (from a tuners standpoint) a motor gets the exact same amount of fuel per each combustion event, it gets the spark timed out just right in each cylinder to make the different combustion events happen, the last really important thing is to have the exact same amount of airflow to each cylinder, I think the only way to truly do that is through exacting cnc work.... Iirc the heads I was looking at had the 2.0 chamber cnc'd out to perfectly match the 2.5, the cam releifs were cnc'd for some big ass cams, surfaces were decked perfectly ( intake, exhaust ,block surface), 3 angle valve job ( I can't remember if he had stock or oversize valves but he said they do both), and he didn't have to screw around with buying bunch of buckets I think they had the valve job/ lash adjusted to use the buckets he already had! They assembled everything with new guides and seats too iirc... Hopefully these chimera heads are in my future for my next mod haha , Anyway lol! That's my take on the whole cnc'd heads deal....

Last edited by TDagen; 03-04-2010 at 07:39 PM.
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Old 03-04-2010, 04:36 PM   #36
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Here is the thread with all our engine and head build options and pricing:

http://forums.nasioc.com/forums/show....php?t=1942703


Here is an excerpt from that thread. Any of these services can be added on with the CNC work. I hope this helps answer some of the questions. I'll also be happy to write up quotes for anything more specific or a slightly different combination of services.

Head Work Options:


EQ Basic Heads:

This is the most basic head work that is required anytime you pull the heads and re-use them on a new block. This insures a true quality surface finish for proper head gasket sealing. This is only recommended for budget minded projects with relatively low mileage heads that should not require a valve job.

- Clean, Inspect, and Vacuum Test
- Precision Resurfacing

Price: $200



EQ Stage 1 Heads:

This service is appropriate for higher mileage heads that require cleanup as well as more performance minded projects. This insures a true quality surface finish for proper head gasket sealing as well as a very precise valve job for unmatched valve sealing which increases overall power efficiency.

- Clean, Inspect, and Vacuum Test
- Precision Resurfacing
- Precision 5-Angle Valve Job

Price: $700



EQ Stage 2 Heads:

This is all the same work as the Stage 1 Heads with the addition of a quality bowl blend to optimize the valve job. This is a performance oriented setup without spending the money for a full port and polish.

- Clean, Inspect, and Vacuum Test
- Precision Resurfacing
- Precision 5-Angle Valve Job
- Bowl Blend (basic P&P)

Price: $950



EQ Stage 3 Heads:

This is the stage 2 head package but with a complete port and polish with gasket matching. This is for the absolute performance oriented builds looking to get the most efficiency possible out of their setups.

- Clean, Inspect, and Vacuum Test
- Precision Resurfacing
- Precision 5-Angle Valve Job
- Full Port and Polish with gasket matching

Price: $1600



Additional Head Build Options:

These are performance oriented options available as add-ons to the Stage 1+ head packages. Combining some of these select parts with the quality machine work offered in the staged packages results in the ultimate head setup for large turbo/power applications.

- Brian Crower Stage 2/Stage 3 Cams - Price: $630 WRX; $670 STI

- Cosworth S1/S2 Cams - Price: $1050

- Brian Crower Single Spring/Titanium Retainer Kit - Price: $250

- SuperTech Dual Spring/Seat/Titanium Retainer Kit - Price: $450

- SuperTech +1mm Oversized Valves (8 intake, 8 exhaust) - Price: $445

- SuperTech Shim-Under Buckets (set of 16 buckets and 16 shims) - Price: $475

- Oversized Valve Installation - Price: $150

- Valve Lash Adjustment - Price: $200 + necessary buckets
Valve lash can only be set properly with the heads torqued down to the block. Therefore this service is only available when we build or have the shortblock in our possession.
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Old 03-04-2010, 04:38 PM   #37
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I hope this helps, please let me know if you guys need any other pricing.

Thanks
-- Ed
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Old 03-10-2010, 07:41 AM   #38
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Very nice. Again, excellent product offering to the Suby community!!!
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Old 03-10-2010, 09:22 AM   #39
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turn around time for blank heads?

i didn't see anything listed.

thank you

--keith
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Old 03-10-2010, 05:01 PM   #40
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Originally Posted by TDagen View Post
Getting the chambers cnc'd out is a good idea... I have a hybrid 2.5l sb with the 2.0 heads, I tune it too. Another main problem no body has mentioned is pre ignition , when your air fuel mixture lights when you don't want it too ... With these hybrids the edge of the 2.0 head that hangs over the 2.5 block gets hot and lights the mixture before the sparkplug gets to... This can lead to catostrophic engine failure btw... No good!
Yes, the 2.0 head & 2.5 SB do not match up exactly - more head overhang. But this isn't necessarily a bad thing as one could argue that it gives more quench surface area, promoting better AF mixing. I agree that one should round out the edges a bit - but I'm not exactly sold on cnc'ing the entire chamber to match a 2.5 head.

For my built engine (a 3MI Racing 2.34 LR setup using a 207 crank), I'm doing ej207 v8 heads on a 2.5 SB using custom pistons that are matched to the 2.0 head. I'll still be rounding out the edges a tad. Should prove interesting...
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Old 03-10-2010, 07:47 PM   #41
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Yes, the 2.0 head & 2.5 SB do not match up exactly - more head overhang. But this isn't necessarily a bad thing as one could argue that it gives more quench surface area, promoting better AF mixing. I agree that one should round out the edges a bit - but I'm not exactly sold on cnc'ing the entire chamber to match a 2.5 head.

For my built engine (a 3MI Racing 2.34 LR setup using a 207 crank), I'm doing ej207 v8 heads on a 2.5 SB using custom pistons that are matched to the 2.0 head. I'll still be rounding out the edges a tad. Should prove interesting...
FYI if your planning on running E85 I would strongly suggest CNCing the chamber...E85 is much more prone to pre ignition... BTW I didn't know there was a need for better a/f mixing ( if it works well dont fix)....Don't forget pre-ignition and misfires are a bad thing , you dont want that headache trust me ...When you shut the car off and start it back up a couple minutes later you could run into problems with the misfires/pre ignition... When you start it back up the ecu is going to boost up the amount of fuel for a minute for start up , that extra E85 tends to light off the hot edges of the 2.0 heads , I dont think just rounding it of is going to make a huge difference imo, but hopefully its enough to deter pre ignition/misfires for the most part. That over hang is going to be heating up faster than the rest of the cylinder plain and simple, like a little wall with fire hitting it each combustion event!...Hopefully it works for you tho.. Sounds like you have a sweet motor in the works! Good luck!!
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Old 03-10-2010, 08:31 PM   #42
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The resulting combustion chamber shape remains inefficient since you're leaving the 2.0l chamber in the heads untouched. You are in essence shrinking the quench area and introducing several sharp edges to the combustion chamber that can build up heat and cause knock.
Aren't you actually reducing possible quench pad area on the piston and combustion chamber by increasing the combustion chambers bore size?


Think you have a few things backwards in your theory there...
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Old 03-11-2010, 02:21 AM   #43
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i read you thread and sounds like your deshrouding the heads in other words. to increase volume in the heads right? i understand you managed to replicate each head efficiently which is pretty awesome for you. but dang your pretty expensive. i know a place that does the same on all for combustion chambers for 150.00 in orange county.
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Old 03-11-2010, 11:31 AM   #44
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^^yeah but it does sound they've done it in a smart way with some kind of design criteria at least...I'm just wondering what kind of design criteria as they have reduced quench pad area when they thought they were increasing it...

equilibrium...hello?
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Old 03-12-2010, 12:14 PM   #45
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Aren't you actually reducing possible quench pad area on the piston and combustion chamber by increasing the combustion chambers bore size?


Think you have a few things backwards in your theory there...
I think the theory is sound, but you're right... I have some of my terminology a bit confused here. The CNC modification technically reduces some of the quench pad area by increasing the combustion chamber size. Although if we're getting really technical, it would be important to define exactly what qualifies as quench area. The tough part to define is how close the piston surface must be to the head surface to qualify as "quench area". Depending on that number, you could still consider the outer edge of the combustion chamber as quench area since it does direct the combustion mixture in toward the spark plugs. I could be wrong, but I don't believe that quench area has to be exactly flat by definition.

Another point to make is that when using a thicker head gasket in a hybrid build without modifying the heads, you're also moving the quench surface on the head farther away from the piston, which in essence the reduces the effectiveness of said quench area. This is really what I was trying to say in my original statement. When you modify the head and use a standard head gasket, you modify the quench area, but you also move the head closer to the piston surface because you no longer need a thicker head gasket. The idea and the result is that you end up with the same quench area as a complete EJ257.

So I suppose a better way of stating this would have been to say that the head modification improves the effectiveness of the quench area as apposed to actually increasing the area. This is of course all in comparison to a hybrid setup with thicker head gaskets.

Thanks for raising the question as its always good to clarify potentially unclear terminology.

-- Ed
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Old 03-12-2010, 12:21 PM   #46
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i read you thread and sounds like your deshrouding the heads in other words. to increase volume in the heads right? i understand you managed to replicate each head efficiently which is pretty awesome for you. but dang your pretty expensive. i know a place that does the same on all for combustion chambers for 150.00 in orange county.
Considering the time we put into mapping out 257 the combustion chamber, developing a CNC program to replicate it, and figuring out how to position and replicate the combustion chamber within 1 thousandth of an inch on every head, every time, I don't believe the price to be expensive at all.

There's always going to be someone out there willing to do something for less money, but that doesn't mean the results will be the same. The combustion chamber is a very critical component of an engine, so we decided to take a very precise approach. Just as an example, all high quality pistons are CNC machined to provide precise, tight tolerances. Why should the combustion chamber be any different?

Thanks
-- Ed
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Old 03-12-2010, 12:22 PM   #47
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Originally Posted by kheff46 View Post
turn around time for blank heads?

i didn't see anything listed.

thank you

--keith
Turnaround on blank heads is 1 week.

Thanks
-- Ed
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Old 03-12-2010, 12:28 PM   #48
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Originally Posted by Rick Hunter View Post
Yes, the 2.0 head & 2.5 SB do not match up exactly - more head overhang. But this isn't necessarily a bad thing as one could argue that it gives more quench surface area, promoting better AF mixing. I agree that one should round out the edges a bit - but I'm not exactly sold on cnc'ing the entire chamber to match a 2.5 head.

For my built engine (a 3MI Racing 2.34 LR setup using a 207 crank), I'm doing ej207 v8 heads on a 2.5 SB using custom pistons that are matched to the 2.0 head. I'll still be rounding out the edges a tad. Should prove interesting...
If you stay with a factory thickness head gasket, you're correct that you get more quench area out of the 2.0 heads. This is only valid if you have enough octane to run that kind of compression ratio. With E85, you may be ok. One thing to note, however, is that the actual quench area is not nearly as critical on a turbo engine as it is with NA. This is especially true with higher boost applications. There is already enough turbulence and cylinder pressure to create a good mixture and aide in combustion. This is why you see a lot of turbo engine designs greatly reduce the quench area as compared to their NA counterparts.

-- Ed
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Old 03-12-2010, 12:33 PM   #49
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I think the theory is sound, but you're right... I have some of my terminology a bit confused here. The CNC modification technically reduces some of the quench pad area by increasing the combustion chamber size. Although if we're getting really technical, it would be important to define exactly what qualifies as quench area. The tough part to define is how close the piston surface must be to the head surface to qualify as "quench area". Depending on that number, you could still consider the outer edge of the combustion chamber as quench area since it does direct the combustion mixture in toward the spark plugs. I could be wrong, but I don't believe that quench area has to be exactly flat by definition.
well the distance of piston to head is known as quench height and hence it is a value taken into consideration when doing engine builds. Also true that quench area doesn't by definition have to be flat to be effective but does need to have a mating face to which it is 'flat' with...think in terms of male and female if not being two flat faces.

Quote:
Originally Posted by Equilibrium Tuning View Post
Another point to make is that when using a thicker head gasket in a hybrid build without modifying the heads, you're also moving the quench surface on the head farther away from the piston, which in essence the reduces the effectiveness of said quench area. This is really what I was trying to say in my original statement. When you modify the head and use a standard head gasket, you modify the quench area, but you also move the head closer to the piston surface because you no longer need a thicker head gasket. The idea and the result is that you end up with the same quench area as a complete EJ257.
That's why a tight quench height is important and something that gets put on engine spec sheets. Also why my solution is as simple as custom pistons which doesn't require shipping heads, although some deshrouding on a larger bore can be nice.

Quote:
Originally Posted by Equilibrium Tuning View Post
So I suppose a better way of stating this would have been to say that the head modification improves the effectiveness of the quench area as apposed to actually increasing the area. This is of course all in comparison to a hybrid setup with thicker head gaskets.
Sounds good to me
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Old 03-12-2010, 12:43 PM   #50
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Quote:
Originally Posted by Equilibrium Tuning View Post
If you stay with a factory thickness head gasket, you're correct that you get more quench area out of the 2.0 heads. This is only valid if you have enough octane to run that kind of compression ratio. With E85, you may be ok. One thing to note, however, is that the actual quench area is not nearly as critical on a turbo engine as it is with NA. This is especially true with higher boost applications. There is already enough turbulence and cylinder pressure to create a good mixture and aide in combustion. This is why you see a lot of turbo engine designs greatly reduce the quench area as compared to their NA counterparts.

In his case, he gets custom pistons that are made for his EJ205 head...no biggy and can run stock gasket too.
On the long rod setup, the smaller combustion volume at TDC is beneficial because of the increased constant volume combustion. There is more to the value than just quench area on some motor setups.
Though your points of quench pad being a factor on forced induction applications is true. It isn't as crucial as an NA setup for the listed reasons.
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