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Old 10-27-2010, 02:34 PM   #1126
scoobystas
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Quote:
Originally Posted by Mohammadov View Post
-6 Psi
I guess its sort of ball park. Im more around -9psi, so -6 means your pulling less vaccum. Possible vacc leak
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Old 10-27-2010, 02:36 PM   #1127
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rear o2 is fine wherever, it should be after the cat but yea either way it will work, just make sure the front o2 is right after the turbo
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Old 10-27-2010, 02:36 PM   #1128
scoobystas
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Originally Posted by K.Linchpin View Post
Question. My cobb DP that I modified to work with my VF37 has a bung for the rear o2 sensor, however, unlike the stock JDM downpipe, this o2 sensor bung is before the high flow cat. So I have two o2 sensors. One right after the turbo and one right before the cat. This seems kind of stupid. Yet my ECU doesn't throw any codes. Should I have another bung welded in after the cat for the rear o2 sensor?
only if you want to stick a wideband O2 sensor in the bung before the cat
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Old 10-27-2010, 03:03 PM   #1129
[JT]
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thanks, im gonna keep looking until i find an 02 spec c front clip
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Old 10-27-2010, 05:02 PM   #1130
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Quote:
Originally Posted by scoobystas View Post
I guess its sort of ball park. Im more around -9psi, so -6 means your pulling less vaccum. Possible vacc leak
Thanx,well,i changed some of the vacuum lines to HKS top quiality ones,but still some lines,i will recheck them..
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Old 10-27-2010, 11:20 PM   #1131
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Originally Posted by Mohammadov View Post
Thanx,well,i changed some of the vacuum lines to HKS top quiality ones,but still some lines,i will recheck them..
definitely sounds like a vac leak unless you have some wild cams in there.
I see 18-19 in/Hg at idle.
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Old 10-27-2010, 11:50 PM   #1132
seanathanq83
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if your reading it on rom raider on manifold absolute i believe its 5.2-6.2 and positive since its MAP
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Old 10-28-2010, 04:34 AM   #1133
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Quote:
Originally Posted by fastnoypi View Post
definitely sounds like a vac leak unless you have some wild cams in there.
I see 18-19 in/Hg at idle.
You know,the shop i bought the engine from and also me,dont know if it has non-stock cams..,imagine there is some HKS Cams

Last edited by Mohammadov; 10-28-2010 at 04:42 AM.
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Old 10-28-2010, 03:22 PM   #1134
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Damn this is a long thread lol. I have worked with some different motors and I know some guys that run 207's and they love them. Their only complaint is the lack of TQ from the 207 vs a 2.5L. So from their own mouths if you want TQ and good track numbers go with a 2.5L if you want uniqueness and high reving top end power then 207 and have fun. And for Non STi owners go with a hybrid build, just make sure to get the right head gaskets to support your heads along with the other supporting mods based on your engine build. Reason being that your ECU cannot support ACVS so you would need to go with a stand alone and spend a ton more money for not THAT big of an advantage. If you want a big turbo power low end tq set up and great numbers the 2.5L is the motor for you!
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Old 10-28-2010, 03:35 PM   #1135
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Quote:
Originally Posted by sleepersaurusrex View Post
Damn this is a long thread lol. I have worked with some different motors and I know some guys that run 207's and they love them. Their only complaint is the lack of TQ from the 207 vs a 2.5L. So from their own mouths if you want TQ and good track numbers go with a 2.5L if you want uniqueness and high reving top end power then 207 and have fun. And for Non STi owners go with a hybrid build, just make sure to get the right head gaskets to support your heads along with the other supporting mods based on your engine build. Reason being that your ECU cannot support ACVS so you would need to go with a stand alone and spend a ton more money for not THAT big of an advantage. If you want a big turbo power low end tq set up and great numbers the 2.5L is the motor for you!
What was the point of this post?

def
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Old 10-28-2010, 04:54 PM   #1136
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Originally Posted by dug-e-fresh View Post
What was the point of this post?

def
To point out that he doesn't really know what he's talking about and can parrot what he's heard... lol.
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Old 10-28-2010, 05:32 PM   #1137
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Originally Posted by fellstar View Post
To point out that he doesn't really know what he's talking about and can parrot what he's heard... lol.
That's pretty much ALL of NASIOC lol.
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Old 10-28-2010, 05:39 PM   #1138
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Originally Posted by Big_DeWeY View Post
That's pretty much ALL of NASIOC lol.
Why hello Dewey. LOL.
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Old 10-31-2010, 04:00 PM   #1139
04ImprezaWRX
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Hey guys went to go check out an ej207 and when i did the leakdown test with 90psi in put pressure the back two cylinders closest to the the firewall came up 83psi output pressure so they were leaking 7 psi. The front two cylinders wouldn't hold any pressure even at top dead center. So while filling the cylinder up we thought maybe it was on the exhaust stroke so we turned the crank over and nothing happened. Both cylinders were like this. We also noticed the one spark plug had no oil on it and was rusty on the part inside the engine. Im going to guess the intake valves arent sealing properly and all the air is leaking out the intake manifold. How hard and expensive is it to fix this? Any reccomendations im trying to work out a deal but want to know what im getting myself into first. Thanks in advance
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Old 11-01-2010, 09:33 AM   #1140
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Originally Posted by 04ImprezaWRX View Post
Hey guys went to go check out an ej207 and when i did the leakdown test with 90psi in put pressure the back two cylinders closest to the the firewall came up 83psi output pressure so they were leaking 7 psi. The front two cylinders wouldn't hold any pressure even at top dead center. So while filling the cylinder up we thought maybe it was on the exhaust stroke so we turned the crank over and nothing happened. Both cylinders were like this. We also noticed the one spark plug had no oil on it and was rusty on the part inside the engine. Im going to guess the intake valves arent sealing properly and all the air is leaking out the intake manifold. How hard and expensive is it to fix this? Any reccomendations im trying to work out a deal but want to know what im getting myself into first. Thanks in advance
You can listen for where the air is leaking by putting an ear to the intake vs the exhaust manifold or oil filler neck.

Depending where the leak is coming from will determine how far you gotta tear it down which will determine how much its gonna cost to fix it. At minimum your looking at bent valves, so "just" a s head rebuild... at worst your looking at a trashed bottom end (fried rings at best, cracked ringlands at worst), so you'd be looking at a complete overhaul.

def
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Old 11-03-2010, 05:17 PM   #1141
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I've been spending time over on scoobynet, and I had a question about some things.

They mention that the ECU is limited to 1.55bar (22psi) and in order to go higher the tuner has to remove "safe guards" ..... which they say is a big "no no". But when I look at most of us here in the US..... with the JDM ECU we are pushing 25-30psi on the stock ECU in some cases.

It might be they are just referring to the EDM ECU which maybe has a lower limit vs the JDM. Def curious to here the rest of your thoughts on this.

Looks like I'm going to go with the SC46 (blouch) since in the end it is about the same price as going with the Litchfield LM450. If I go with Blouch it's $1595 and I have to send them my VF37. If I go with Litchfield it will cost about $2500 with shipping but I keep my VF37 which I can flip for $700-900. Plus I haven't noticed much difference in power when comparing results from diff people. I do like the billet wheel on the SC46 though. Decisions decisions
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Old 11-03-2010, 06:08 PM   #1142
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they may be talking about the absolute "boost cut" limit which can be changed in the ecu.
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Old 11-03-2010, 06:18 PM   #1143
Clark Turner
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The boost cut or the ecu is not limited to 22 psi. Its only limited by the tuner that tunes the car and the tools he uses.

C
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Old 11-03-2010, 06:21 PM   #1144
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Quote:
Originally Posted by scoobystas View Post
they may be talking about the absolute "boost cut" limit which can be changed in the ecu.
I looked into it some more, looks like the JDM ECU can read 1.7bar vs the EDM ECU's 1.55bar. Sounds like the ECU's sensor can't read/register anything over that, so to boost further you would need an MBC which removes the ECU safe guard of it knowing the boost.
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Old 11-03-2010, 06:26 PM   #1145
Clark Turner
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Incorrect. You can set the boost cut to well over 30 psi.

C
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Old 11-03-2010, 06:35 PM   #1146
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Originally Posted by Clark Turner View Post
Incorrect. You can set the boost cut to well over 30 psi.

C
Interesting, I wonder what the hell they are talking about then...... I keep reading the tuners saying "ECU can't see over 1.55/1.7bar unless you remove safe guards".
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Old 11-03-2010, 06:42 PM   #1147
Clark Turner
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In the factory rom file, that is how it is setup. They dont know how to tune the rom so they just say this is the limit.

cya

C
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Old 11-04-2010, 08:28 PM   #1148
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Here was his response

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There are two issues that relate to the maximum safe boost, from an electronics point of view....

The first is the maximum boost pressure the sensor can read. This varies from year to year and also between JDM and EU markets. The basic premise is that you cannot set the boost cut any higher than this, otherwise the boost cut is disabled since regardless of what boost is made, the sensor will not see it. Typically this sits around 1.7 bar, but can be as high as 2.05 bar on the JDM Twin Scroll engines or as low as 1.1 bar on MY92-96 cars (bar potentially the 555 edition). Due to the poor boost control strategy in all standard ECUs it is virtually impossible to achieve target boost without some overshoot, therefore there needs to be some "headroom" between the target and the cut. This headroom will typically be 0.15 to 0.2 bar; if we have a sensor that reads to 1.7 bar then that places our maximum safe boost target at 1.5 bar. It can be higher on cars with sensors that read higher but that is not the end of the story :

The SelectMonitor protocol has an upper limit of 255 kPa absolute for the manifold absolute pressure parameter and 128 kPa gauge for manifold relative pressure. In simple terms, DeltaDash will not be able to display boost beyond 1.55 bar, regardless of how high it really is. This is not a major problem when a car has a boost gauge because that can be used during road test to verify boost control; whilst on the dyno of course the dyno boost pressure sensor is used and it can read 4 bar of boost. If a car does not have a boost gauge then it becomes impossible to verify correct boost control operation on the road without fitting, and removing, a "loan" boost gauge. Whilst this is possible, it is an additional amount of labour and expense which would be incurred every time the car is looked at, so unless a car will be fitted and retain its boost gauge, mapping beyond 1.55 bar will not be offered on stock ECU. Mapping beyond the limits of the map sensor will never be offered, removing the safety features simply isn't an option as far as we are concerned.

As a final note, some ECUs also implement a maximum load cap. The engine load is calculated by dividing the airflow by the RPM. The result is used to lookup the right fuel and ignition, and of course if that value is capped, additional boost and airflow cannot be dealt with safely. A typical example of this is an EG257 in an MY99-00 car; the AE80X and AF04X/AG340 cap around about 57, but you can get that with just 1.25 bar on an EJ257, sometimes at less boost. There is no proper engineering solution to this, only various band aids.... rescaling the airflow to fool the ECU into thinking it is flowing less air (and thus reducing the computed load) then richening the fuel map to compensate and adjusting the ignition table to compensate for the fudged engine load is one such method and a "get me out the poo" option but sanity checking such a map becomes an exercise in mental arithmetic, trying to keep track of the real load by correcting the fudged figures in your head as you see them; certainly a recipe for mistakes to be made. It is always better to deploy a properly engineered solution that doesn't rely of pseudo-figures to make a square peg fit a round hole, but I do appreciate that is sometimes the only viable option there and then.

Hope this sheds some light on the situation,

Pat.
Quote:
1) You can fit a larger range sensor to get round the ECU being able to "see" the boost, but there are further caveats.... ideally you want to be able to re-scale for the new sensor so that the reading is true. This will of course make the overall solution subject to 2) below but it is better to work with real figures. If the sensor cannot be rescaled then you're back to using pseudo-readings and the whole thing a little more difficult to work with.... it doesn't help when the ECU says it's running 1 bar only to find that it's really 1.4 bar, but that can and does happen...

2) The limitation applies primarily to what we can "see" from the outside. The ECU can represent more than 255kPa internally and we can set a target higher than this, and also set a limit higher too, but since we cannot "see" it, we cannot know if the limit we have set is actually achievable. Let's say that we set the limit at 272kPa but the sensor can only register 271kPa, in order to "prove" that the limit works we MUST exceed 272 kPa for a period of time, something you may not want to do. You cannot "check" that the sensor stops reading at 271kPa with DeltaDash because anything over 255kPa will read 255kPa...

3) I hadn't touched on the MAF reading limit, I was talking about load limit, but the same applies. You can fit a bigger MAF tube and scale... BUT regardless of what the turbo can flow, you cannot see more than 300g/sec. So let's say the turbo flows 450g/sec. You rescale the MAF so that the real 450g/sec reads 300, ie you downscale to 66% of real airflow. Then you would re-scale the injectors the same amount, say they were 750cc/min, you'de enter them as 500cc/min. This will cause the injection pulse width to be 1.5 times as long as it "should" be, and 0.66 * 1.5 = 1.00, ie the correct amount of fuel gets delivered. Of course the load axis on the ignition table will now be wrong, that is to say where in reality it maybe should read 7.5g/cycle it will now only read 5 g/cycle so the ignition values that should have been in the 7.5 row, if it had been possible to "see" 450g/sec will now be in the 5.0g/cycle load row. This type of thing is a fudge, you are no longer working with real values. By contrast the later ECUs can see more than 300g/sec and you'de do the job properly by scaling the MAF readings so that you genuinely do see 450g/sec.

It would not be a speed density ECU if you used a MAF. In order to go speed density you'de want to a) use something like the HKS VPC (no longer made, I wonder why...), MAFSIM (no longer made, I wonder why...), or indeed use a proper speed density ROM file (STi Group N, not officially available to anyone outside STi).

At present there is no viable solution that addresses all of the limitations of the standard ECU. ECUTEK are quite busy with cool new features that may redress that balance but for now, if you want to go speed density then the only way to do it legitimately (ie not using stolen ROM files) is to replace the ECU.

Hope this helps,

Pat.
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Old 11-04-2010, 08:32 PM   #1149
Clark Turner
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This person is confused.


C
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Old 11-04-2010, 09:10 PM   #1150
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This person is confused.


C

Last edited by LIQUIDSK8S; 11-04-2010 at 10:34 PM.
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