Possibly 10Hp easy
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Joined: Jan 2003
Posts: 144
From: Colorado
Car Info: 2000 2.5 RS USDM STI block, SOHC heads GT25 Ball bearing turbo, TMIC, TXS BOV, Tial wastgate, etc...
Possibly 10Hp easy
Here is the deal.. people have been complaining that EJ25's hesitate when you change the plugs, and the thing to do is crank them down so that they are snug.. Here is a permanant fix... Take a cable from the (-) negative side of the battery and connect it to one of the nuts on each valve cover.. The plugs will have a definite (-) contact, and will be "properly" grounded. I did this today, and it made a HUGE difference. Try it and let us know.
Thread Starter
Registered User
Joined: Jan 2003
Posts: 144
From: Colorado
Car Info: 2000 2.5 RS USDM STI block, SOHC heads GT25 Ball bearing turbo, TMIC, TXS BOV, Tial wastgate, etc...
absolutely nothing.. I was just saying that sometimes tourqing the plugs won't stop the hesitation.. The reason the plugs need to be crnaked down, is to insure propper contact for grounding.. If you give tem a better ground. Cranking them down isn't all that important anymore.... Does that make sense>
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Joined: Dec 2002
Posts: 158
From: Woodside, CA
Car Info: 03 Blu WRX, vf 34, headers, catless, gc coilovers, f/r sways
Ok. As long as the plugs are clean and secure they should be gounded just fine, don't go to tight because you will strip the threads on the block.
Suby's are actually grounded quite well at several different points, but if you want to improve the ground don't add more
cables, just replace the main ground with a 0 guage cable. the current ground is abut a 4 guage which is typical for 12 volt systems. It is sufficient, but could be better.
Old Dude Ramble mode on/
Back in the day when there were 6volt systems, the 6 volt battery had to be able to turn an electric starter motor to start 4,6,8 and even 12 cylinder engines. The way they did this is by using high amperage batteries. Similar to high amerage stereo amplifiers you are able to create short bursts of high engery. To conduct this energy though you need high bandwith cable.
So, like the thick monster cable, they used 0 or 00 guage solid core copper cables. 0 or 00 guage is about as thick and an average guys . . . index finger. It will carry huge amounts of amperage.
So, like on your stereo, instead of installing multiple grounds (or multiple strands of speaker wire) use the existing grounding points to install much thicker cable. BUT, for it all to work, you should also install thicker postive lead cables as well. Right? Because like your high watt and amp stereo the current flow is circular.
Old Dude Ramble mode off\
I believe most auto stores only sell wimpy 4 guage cables but if you have a Napa auto parts store near by they may have it. Also, welding supply companies carry 0 and 00. http://www.newenglandsolar.com/catal.../catalog64.htm
These guys have 0, 00, 000 and even 0000 guage (4/0).
Good luck!
Hmmm, with all that said, I am not sure there is a problem with the current ground of the car.
Suby's are actually grounded quite well at several different points, but if you want to improve the ground don't add more
cables, just replace the main ground with a 0 guage cable. the current ground is abut a 4 guage which is typical for 12 volt systems. It is sufficient, but could be better.
Old Dude Ramble mode on/
Back in the day when there were 6volt systems, the 6 volt battery had to be able to turn an electric starter motor to start 4,6,8 and even 12 cylinder engines. The way they did this is by using high amperage batteries. Similar to high amerage stereo amplifiers you are able to create short bursts of high engery. To conduct this energy though you need high bandwith cable.
So, like the thick monster cable, they used 0 or 00 guage solid core copper cables. 0 or 00 guage is about as thick and an average guys . . . index finger. It will carry huge amounts of amperage.
So, like on your stereo, instead of installing multiple grounds (or multiple strands of speaker wire) use the existing grounding points to install much thicker cable. BUT, for it all to work, you should also install thicker postive lead cables as well. Right? Because like your high watt and amp stereo the current flow is circular.
Old Dude Ramble mode off\
I believe most auto stores only sell wimpy 4 guage cables but if you have a Napa auto parts store near by they may have it. Also, welding supply companies carry 0 and 00. http://www.newenglandsolar.com/catal.../catalog64.htm
These guys have 0, 00, 000 and even 0000 guage (4/0).
Good luck!
Hmmm, with all that said, I am not sure there is a problem with the current ground of the car.
Last edited by WillysPU; Feb 27, 2003 at 09:44 AM.
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Another possible reason for the hesitation is because of the oversensitive knock sensor. Since you change the plugs all of a sudden the car has more power, since the stock plugs are crap. So the car starts pulling timing to compensate for the better plugs. This is true on the RS engines from 99 and up. The SOHC are just not as good as the DOHC from 98, which never really had this problem, as the engine was designed much much better.
Ever wonder why the newer engines have 10:1 compression and the same amount of horsepower as the 9.7:1 compression of the 98? The 98's are tuned very safe, where as the 99 and up are tuned a little bit less safe because they still need to make the same amount of power.
This is just from years of experience I have figured this stuff out with a few other poeple.
Ever wonder why the newer engines have 10:1 compression and the same amount of horsepower as the 9.7:1 compression of the 98? The 98's are tuned very safe, where as the 99 and up are tuned a little bit less safe because they still need to make the same amount of power.
This is just from years of experience I have figured this stuff out with a few other poeple.
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Joined: Dec 2002
Posts: 158
From: Woodside, CA
Car Info: 03 Blu WRX, vf 34, headers, catless, gc coilovers, f/r sways
Sorry I may have missed that new plugs were added, you may also want to check the gap on the plugs.
On the WRX if you go one step cooler, the gap should be between .026-.028. At least per Vishnu's recomendation."0.026-0.028 inches. Too much bigger and you will get misfire. Too much smaller and idle quality will suffer."
On the WRX if you go one step cooler, the gap should be between .026-.028. At least per Vishnu's recomendation."0.026-0.028 inches. Too much bigger and you will get misfire. Too much smaller and idle quality will suffer."
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Posts: 10,029
From: Sacramento CA
Car Info: 02 Impreza WRX sedan
Originally posted by WillysPU
On the WRX if you go one step cooler, the gap should be between .026-.028. At least per Vishnu's recomendation."0.026-0.028 inches. Too much bigger and you will get misfire. Too much smaller and idle quality will suffer."
This must be a limitation of the factory ignition. Old school hot rodders used to claim a horsepower gain on the dyno with plug gaps opened up to 0.10", but everything in the ignition system had to be upgraded (plug wires, HEI-style distributor cap with widely spaced secondary terminals, long duration or multi-spark ignition box such as MSD-7AL) to prevent spark plug wire induction leakage to adjoining wires or engine metallic surfaces.
With WRX ignition coils mounted directly to spark plug end there is no leakage, so small plug gaps must be necessitated by high cylinder pressure and insufficient energy output from the OEM ignition. I wonder if MSD or other companies are working on a plug-and-play ignition box for the WRX...
--
^ww^
"…axles of evil…" - George W. Bush
On the WRX if you go one step cooler, the gap should be between .026-.028. At least per Vishnu's recomendation."0.026-0.028 inches. Too much bigger and you will get misfire. Too much smaller and idle quality will suffer."
This must be a limitation of the factory ignition. Old school hot rodders used to claim a horsepower gain on the dyno with plug gaps opened up to 0.10", but everything in the ignition system had to be upgraded (plug wires, HEI-style distributor cap with widely spaced secondary terminals, long duration or multi-spark ignition box such as MSD-7AL) to prevent spark plug wire induction leakage to adjoining wires or engine metallic surfaces.
With WRX ignition coils mounted directly to spark plug end there is no leakage, so small plug gaps must be necessitated by high cylinder pressure and insufficient energy output from the OEM ignition. I wonder if MSD or other companies are working on a plug-and-play ignition box for the WRX...
--
^ww^
"…axles of evil…" - George W. Bush
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