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Old 10-01-2009, 07:22 PM   #1
rs182
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Default late ej20g (20k) engine timing

I am going to start up my swapped rs this weekend. As of now I have safc and sitc piggy backs. Seeing how it is a 97 forester it is the bastard late g motor. I know the 20k get bad wrap for spinning bearing because of low octane fuel and not pulling enough timing. So my question is how much should I retard the timing to make it safe for 91 octane. I will be getting it tuned next month (have to drive to phx, AZ)but I want to start driving her. It is completely stock so I should not need to mess with any a/f numbers. Being that is a forester late 20g(20k) it already has a less agressive timing curve than say a sti 6s ecu. (250hp vs 280). So all you g,k gurus school me on this

and yes i am ready to be flamed for not getting a pro-tune immediately.
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Old 10-01-2009, 07:34 PM   #2
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so you are using the G ecu right...

if your worried i would direct connect the wastegate and take her easy
det under low load is not an issue

should be fine with 91
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Old 10-01-2009, 07:40 PM   #3
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yea it is a g ecu but it uses the k style plugs so I am not sure how much more aggressive the ecu is. Am i correct in thinking that using a knock light and the sitc I can simply retard the timing until there is no knock at the given rpm?
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Old 10-02-2009, 12:17 AM   #4
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the late ej20g with 20k style electronics makes the least power of that year range (for turbo models). its got a td04 which is a small turbo (still larger than the usdm td04 though AFAIK). the real problem is with the jdm ej20k sti ECUs like the 6S ecu that i have, runs 17lbs boost stock, which is quite a bit from the factory. so if you get an ECU from a plain ej20k wrx (one that had a td05 for example) then you could push your current setup further but not so far as a vf22/vf23 jdm ej20k sti (which would have bigger injectors, fuel pump, shim under bucket, etc)
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Old 10-02-2009, 01:26 AM   #5
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Quote:
Originally Posted by elislider View Post
the late ej20g with 20k style electronics makes the least power of that year range (for turbo models). its got a td04 which is a small turbo (still larger than the usdm td04 though AFAIK). the real problem is with the jdm ej20k sti ECUs like the 6S ecu that i have, runs 17lbs boost stock, which is quite a bit from the factory. so if you get an ECU from a plain ej20k wrx (one that had a td05 for example) then you could push your current setup further but not so far as a vf22/vf23 jdm ej20k sti (which would have bigger injectors, fuel pump, shim under bucket, etc)
How are the heads on this Forester EJ20G (EJ20K actually) vs. the ones found on the STI EJ20K's?
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Old 10-02-2009, 02:06 AM   #6
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the late ej20g and plain ej20k is shim under bucket very similar to the USDM 1998 2.5RS and USDM 1998 forester. they are similar in valve train features but the jdm has slightly larger ports and better valves and cam profile for the turbo model. the v3/v4 STi is shim under bucket and sodium filled valves, overall tougher valvetrain which can endure higher and more sustained revs (within reason). hence why the factory fuelcut on a v3/v4 sti is 8250 and for the plain wrx its lower like 7800 or something

marnix/matt/jaxx could provide more specifics
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Old 10-02-2009, 02:10 AM   #7
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The head castings are identical to all MY97-98 DOHC heads including USDM EJ25D, JDM EJ20G, EJ20H, EJ20K and EJ20R. The differences are in valves (solid or hollow/sodium cooled), valve springs and shim arrangement (under - or over bucket) and cams. This all has influence on rev limit and power range.

Considering the rs182 is using a EJ20G out of a Forester, he should also consider that the engine has a higher compression ratio (9.0 vs. 8.0) compared to a EJ20K meaning he will have to be even more conservative regarding timing under boost.

When using the ECU that came with that engine, however, the engine should be fine on 91 gas as the maps are far less aggressive as the EJ20K's. Still, when driving, start carfefully and monitor knock.
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Old 10-02-2009, 08:36 AM   #8
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Quote:
Originally Posted by rs182 View Post
Am i correct in thinking that using a knock light and the sitc I can simply retard the timing until there is no knock at the given rpm?
You don't want to just wire in a knock light in series. This will interfere with the voltage of the signal that is sent to your ECU for it's reference with respect to knock. If you want to do this, you will want to purchase a seperate knock sensor and mount it.

Maybe that's what the sitc is? (I hate when people throw out random abbreviations that aren't in common usage). Obviously sitc is some sort of timing controller, but exactly what that is isn't clear to me...
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Old 10-02-2009, 08:43 AM   #9
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Quote:
Originally Posted by elislider View Post
the late ej20g with 20k style electronics makes the least power of that year range (for turbo models). its got a td04 which is a small turbo (still larger than the usdm td04 though AFAIK). the real problem is with the jdm ej20k sti ECUs like the 6S ecu that i have, runs 17lbs boost stock, which is quite a bit from the factory. so if you get an ECU from a plain ej20k wrx (one that had a td05 for example) then you could push your current setup further but not so far as a vf22/vf23 jdm ej20k sti (which would have bigger injectors, fuel pump, shim under bucket, etc)
late ej20g=td04
ej20k=vf22
ej20ksti=vf23/vf24

all have the same injectors
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Old 10-02-2009, 09:41 AM   #10
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Eh no, not the late EJ20G they have the dark grey tops, same as all pre-1997 EJ20G (except some STI versions). Only the EJ20K had the yellow top injectors.
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Old 10-02-2009, 04:26 PM   #11
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Quote:
Originally Posted by Marnix View Post
The head castings are identical to all MY97-98 DOHC heads including USDM EJ25D, JDM EJ20G, EJ20H, EJ20K and EJ20R. The differences are in valves (solid or hollow/sodium cooled), valve springs and shim arrangement (under - or over bucket) and cams. This all has influence on rev limit and power range.

Considering the rs182 is using a EJ20G out of a Forester, he should also consider that the engine has a higher compression ratio (9.0 vs. 8.0) compared to a EJ20K meaning he will have to be even more conservative regarding timing under boost.

When using the ECU that came with that engine, however, the engine should be fine on 91 gas as the maps are far less aggressive as the EJ20K's. Still, when driving, start carfefully and monitor knock.
thanks for the correction on head castings. i thought the jdm ones were better flowing though? or am i thinking of these DOHC heads vs. usdm wrx heads?
Quote:
Originally Posted by Jaxx View Post
late ej20g=td04
ej20k=vf22
ej20ksti=vf23/vf24

all have the same injectors
i know td05 was on some of early ej20gs but when was the td05 straight-inlet? or was there ever one stock
Quote:
Originally Posted by Marnix View Post
Eh no, not the late EJ20G they have the dark grey tops, same as all pre-1997 EJ20G (except some STI versions). Only the EJ20K had the yellow top injectors.
werent there different variations (i heard up to 3 variations) of yellowtops? some say 440 some say 480
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Old 10-02-2009, 04:29 PM   #12
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There are different yellow tops on the MY99> engines, they're supposed to be 440cc whereas the earlier yellow tops (EJ20K and EJ20R) are 550cc.
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Old 10-02-2009, 05:06 PM   #13
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Straight inlet td05 was never a factory thing. Starting with v3, all STi's and 5MT Sedans got IHI VF series turbos while all the others got td04s. Straight inlet td05 are an aftermarket thing.
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Old 10-02-2009, 05:29 PM   #14
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Quote:
Originally Posted by Marnix View Post
There are different yellow tops on the MY99> engines, they're supposed to be 440cc whereas the earlier yellow tops (EJ20K and EJ20R) are 550cc.
interesting. i was told idk how many times my v3 sti r/ra had 440 or 480cc yellowtops. good to know they are 550
Quote:
Originally Posted by Matt Monson View Post
Straight inlet td05 was never a factory thing. Starting with v3, all STi's and 5MT Sedans got IHI VF series turbos while all the others got td04s. Straight inlet td05 are an aftermarket thing.
I knew about the VF series stuff but thats more good info, thanks
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Old 10-02-2009, 06:14 PM   #15
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Quote:
Originally Posted by Matt Monson View Post
You don't want to just wire in a knock light in series. This will interfere with the voltage of the signal that is sent to your ECU for it's reference with respect to knock. If you want to do this, you will want to purchase a seperate knock sensor and mount it.

Maybe that's what the sitc is? (I hate when people throw out random abbreviations that aren't in common usage). Obviously sitc is some sort of timing controller, but exactly what that is isn't clear to me...

Wow I as at work all day and I come home to a **** load of posts lol Thats awesome. The SITC stands for super ignition timing converter. It is an apexi product that has now been discontinued but it still in wide use. Basicly it intercepts the cranks position senor and cams position sensors and allows you to advance or retard your timing up to 15 degrees either way at 5 different rpm levels. The knock light I am running is a turboxs knock light. They swear that it doesnt interfere with the stock sensor reading but maybe a different sensor is a good idea.

Thanks to everyone for all the input! I know these late g's are confusing to alot of people. It is great to have some suby gurus to clear stuff up for newbies

It sounds like I will go ahead and run this on 91 as is for a while and just take it easy.

thanks everyone
Jason
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Old 10-02-2009, 06:20 PM   #16
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One more thing.... I have heard various hp numbers for this motor ranging from 190 to 265 but 250 comes up the most. Is the 250hp number correct? I would like to think it is at least more that a usdm wrx
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Old 10-02-2009, 06:27 PM   #17
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so theres a difference in the WRX 20K and the forester engine??...hmmm..thats something new
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Old 10-02-2009, 06:36 PM   #18
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I think they are the same? I am pretty sure the wrx wagons came with the late g as well as the forester. Mine has a 4w ecu. Not sure how that compares with the wrx guys.
Also I was not aware that the g had a higher compression ratio than the k either I was under the impression that the internals were the same. Im glad I posted before I threw on a 6s ecu and a vf23!
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Old 10-02-2009, 07:58 PM   #19
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Quote:
Originally Posted by rs182 View Post
The SITC stands for super ignition timing converter. It is an apexi product that has now been discontinued but it still in wide use.
Leave it to the Japanese. I'm surprised there's not an "extra special" in front of that making it the ESSITC. I actually own one. I've just never heard it called that before. I've just always seen it referred to as an Apexi ITC.

Since we're going back into the dark ages of tuning these cars, the J&S Safeguard was a popular aftermarket knock sensor in it's day. Not only did it sense, but it also automatically retards when it gets knock, much like the stock ECU is supposed to do.
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Old 10-03-2009, 01:08 PM   #20
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there is still disagreement on the ej20k yellow sidefeeds
i believe they are 480cc @ 3 bar
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Old 10-03-2009, 03:17 PM   #21
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Quote:
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there is still disagreement on the ej20k yellow sidefeeds
i believe they are 480cc @ 3 bar
you and marnix should duke it out on this one
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Old 10-03-2009, 03:23 PM   #22
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No could be they are 480 cc; I only know they're bigger than the grey tops and the only other engine they were in besides all EJ20K, is the TwinTurbo EJ20R.
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Old 10-03-2009, 04:53 PM   #23
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IIRC i_c_the_light actually had a set tested and posted teh results. Though it could have been for the greys. Wouldn't hurt to search if people really care. I don't.
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Old 10-04-2009, 01:56 AM   #24
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It would be nice to test a grey top and a yellow top simultaneously to see the difference between them.
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Old 01-09-2010, 06:29 AM   #25
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New version has headphone output and knock-finder LED's to show which cylinders are knocking.

Google "knock amp interceptor"
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