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Guest Message by DevFuse
 

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Interesting HG info


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34 replies to this topic

#26 nipper

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Posted 11 July 2006 - 06:08 PM

One...because they're in it to make money, and by charging you to replace the headgasket....they make money.

Either way, I doubt that stuff works.


in theory i can see it working, espcially with a pin hole leak. The thing is pin hole HG leaks dont stay pin hole leaks very long.
The other part i am suspisous of is the ceramic part (it syays that on the label). Ceramics are known for maintiaing thier dimensions in major temp deviations, where as a HG has to expnad and contract with the engine.
Als the ones on the testimonial pages tend to be cast iron enigines or blocks.

nipper

#27 blitz

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Posted 11 July 2006 - 06:15 PM

This is an excerpt from a rather wordy diatribe from Mike at SPD in '98 regarding the suitability of the 2.5 for aftermarket turbo kit: (he voted NO)

**** ******!
----------------------------------------------
"There is obviously a ground swell of interest (if not actual cash) in
finding some way of turbocharging the US engines. The fact remains that
although the redesigned K series turbo motor cases have an open deck
design, it does not follow automatically that the EJ25G DOHC engine used in
North America is cleared for take-off. There were and remain additional
issues to consider. Simply put, when first asked about turbocharging the
2.5, the open-deck issue was first on the list and made further discussion
to my mind pointless. Lest we give an answer in search of a question, let's
ask this question: Does the 1998 2.5 RS DOHC or 1999 SOHC engine have
common design features with the open deck or closed deck turbo motors? Here
is the information I have been able to assemble. It may not be the final
answer, but it is what I have been told.

We know that the issues that resulted in the open-deck K series motor were
answered as a result of lower demands being placed on the engine due to
changes in racing rules and from actual design changes made by Subaru
engineers. However, one can not assume turbocharging has been evaluated in
the EJ25 engine. The following remarks were made to me by a Subaru
engineering person, who should remain anonymous. They stated that the 2.5
DOHC engine was a "damn the gas mileage, give me some torque" responce to
US market needs and is a "stretched" design specification engine. As a
"stretched" design, it was produced with no consideration of additional
mechanical/thermal stresses of high power and/or rpm. For the sake of the
argument, its power output at 165hp is as near its design limit as a "K"
series WRX engine is at its 280hp output. In contrast, during the same
conversation, the closed deck Japanese EJ20G turbo block and the older
91-93 American closed deck EJ22 turbo block were considered "bullet proof".
This person had no personal knowledge of open deck WRX engines at the time
we spoke.

It was specifically mentioned to me that the thrust bearing area is known
to be marginal WHEN CONSIDERING MORE POWER. Note the emphasis. Not that the
engine has a design problem - that was not the point. The point was if one
were to take the engine out to some big torque and horsepower numbers, the
bottom end was a limiting factor. This implies that the bearing webs in the
case would "walk" under the torsional loads of large power output, where at
the designed 165hp this was simply not an issue. This type problem has been
true for many engine designs over the years, by the way. Second, the
cylinder head and water jackets were not designed for the thermal stress of
turbocharging. Third is the thickness of the cylinder wall. This is a
particularly important issue when it comes to the head gasket area in an
open deck design. From the brief conversations I have had with Subaru staff
it was made clear that no special attention was paid to potential stress
from high output in the design process of the EJ25 DOHC engine. In
contrast, the design of the EJ20G Turbo motor saw every area of design was
gone over in the "WRX-RA" series engines with a mind to 400hp output. This
is the most important point that one needs to know when assessing the 2.5
motor. Just where are the limits? I was left with the impression they are
lower, rather than higher than one would assume from the rally heritage of
the turbo EJ series Subaru boxer engines.

What else can I say? I was sitting there having this conversation about the
RS 2.5 engine and feel it should be made public. It does not mean one can
not supercharge or turbocharge the 1998 EJ25 engine to a nice 250hp. It
just means that SPD Tuning Service is not going to develop a kit for this
purpose, as I will also very seldom bet on less than a pair jacks when
playing five card poker. The odds are not in my favor. Especially with the
typical urge, myself included, to turn up the boost.

In the same conversation, I was told that 1999 2.5 SOHC engine has
addressed the bottom end concerns. Of the two engines the DOHC 98RS and
SOHC 99RS, I was told the SOHC engine is a much stronger engine. In
driving the SOHC engine, it does seem to be a smoother, tighter engine on
the top end, indicative of a stronger case, among other changes. The new
1999 EJ25 however, along with a 1.8 and a 2.0 version, is a family of
"lean-burn" combustion chamber/engine management engines. I do not know how
the this aspect will play into the high pressures and temperatures of
turbocharging, nor if the valve and seat material is up to the higher local
temperatures seen in turbo motors. So again, spending the big money and
developing a reliable turbo setup remains an open issue for me. On the
other hand, I suspect that if we see a turbo motor, it will be a 2.X SOHC,
non-intercooler engine from this new family, with the necessary engineering
changes. This part of the puzzle is starting to make sense, as it is
unlikely we will see the EJ20K with the extra cost of the DOHC heads and
intercooler. The fact that we have only 92 octane gas would effectively
limit this motor to 220hp on a hot, dry day, where a 220hp 2.5 would be
much less near the edge."

#28 blitz

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Posted 11 July 2006 - 06:22 PM

Here's the URL if you want to read the whole thing.

http://legacycentral.org/library/literature/mike_turbo.htm

**** ******!

#29 nipper

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Posted 11 July 2006 - 06:25 PM

Here's the URL if you want to read the whole thing.

http://legacycentral.org/library/literature/mike_turbo.htm

**** ******!


*note to self*
JDM twin turbo 2.0L for Blu.

nipper

at least it explains the reasons for the twin cams.

#30 rlsimpso

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Posted 11 July 2006 - 06:32 PM

I am looking in to the same thing for my GT. Let me know if you get anywhere with that.

#31 nipper

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Posted 11 July 2006 - 06:38 PM

I am looking in to the same thing for my GT. Let me know if you get anywhere with that.


you first. im still laid up with from back surgery and some leg paralysis for the rest of this year.
Say anyone on long island have an SVX i can try on for size?


nipper

#32 rlsimpso

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Posted 11 July 2006 - 06:42 PM

Hmm... new roof or put one of these in my Legacy: http://cgi.ebay.com/...sspagenameZWDVW

Damn, deprecation is a ***************.

#33 rlsimpso

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Posted 11 July 2006 - 06:46 PM

This one is on NJ, thats kinda close: http://cgi.ebay.com/...1QQcmdZViewItem

Next closest is Florida:-\

#34 nipper

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Posted 11 July 2006 - 06:48 PM

Hmm... new roof or put one of these in my Legacy: http://cgi.ebay.com/...sspagenameZWDVW

Damn, deprecation is a ***************.


there is a guy that sells them on ebay complete with ecu and harness.
Which leads me to the question, how do you get parts for them.

nipper

#35 nipper

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Posted 11 July 2006 - 06:49 PM

This one is on NJ, thats kinda close: http://cgi.ebay.com/...1QQcmdZViewItem

Next closest is Florida:-\


i soooooooooooooooooooooooooooooooooo want an svx, but i need to make sure i can get my leg that wont bend properly into one first.

nipper




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