Member Profile - Andy_Mac's JDM '06 GT-B

[alexeiwoody]

Cheers for the info.

Not sure about the scaling. Yes, the first revision was done when the leaking BOV was present but from what Matt was saying it sounded more like he was using a generic setup he'd used before for that same intake so it could still be that it isn't quite right for my one. Still awaiting a reply from him.
Also won't rescaling the MAF at this point cover up a leak if there is infact one present, not rhat I really think there is one.

If you have a real mechanical issue, whether it's a leak or some other problem, re-scaling the MAF should have no effect on it. As it will still try and correct for it either way, as AFRs won't be right.

If you rescale it and the LV is clean from there on - probably all good (would need a log of O2 sensor in open loop to confirm).

This is where a wideband O2 sensor comes in very handy, as it allows you to see the real AFRs in open loop (which the LV won't show, you need to at least post up a log with a WOT pull) - and diagnose if one of your OEM sensors is playing up or if your engine is in trouble.

[andy_mac]

Wideband is on the cards, just haven't decided on a location i'd be happy with. Unless I just hide it away and only use it connected to the Tactrix for logging. Doing a few logs tonight so i'll put one of those up.

[alexeiwoody]

Wideband is on the cards, just haven't decided on a location i'd be happy with. Unless I just hide it away and only use it connected to the Tactrix for logging. Doing a few logs tonight so i'll put one of those up.

Get a gauge with it if possible. It's so simple, but saves so many headaches diagnosing issues on these cars. As soon as you have a vac leak or a fuel related issue, you'll know (it'll go lean or rich etc) without having to whip out the laptop.

[andy_mac]

Those ones are fairly steep but the spring pressure failsafe is pretty nifty.
http://www.innovatemotorsports.com/products/psb1.php

How quick do other people's stock o2's start operating? Is it time or temperature dependent? Or does the element start warming as soon as the car starts and starts reading once thats up to temp? Believe there is some sort of enrichment table when starting from cold but always thought my one was rather slow to get running. Still need to do a log from cold to when it starts operating to confirm

There's a couple of 2nd and 3rd logs, think i've set the google drive permissions correct for anyone to view

https://docs.google.com/file/d/0B_0U1z9 ... pe=msexcel

https://docs.google.com/file/d/0B_0U1z9 ... pe=msexcel

https://docs.google.com/file/d/0B_0U1z9 ... pe=msexcel

https://docs.google.com/file/d/0B_0U1z9 ... pe=msexcel

[alexeiwoody]

Those ones are fairly steep but the spring pressure failsafe is pretty nifty.
http://www.innovatemotorsports.com/products/psb1.php

How quick do other people's stock o2's start operating? Is it time or temperature dependent? Or does the element start warming as soon as the car starts and starts reading once thats up to temp? Believe there is some sort of enrichment table when starting from cold but always thought my one was rather slow to get running. Still need to do a log from cold to when it starts operating to confirm

There's a couple of 2nd and 3rd logs, think i've set the google drive permissions correct for anyone to view

https://docs.google.com/file/d/0B_0U1z9 ... pe=msexcel

https://docs.google.com/file/d/0B_0U1z9 ... pe=msexcel

https://docs.google.com/file/d/0B_0U1z9 ... pe=msexcel

https://docs.google.com/file/d/0B_0U1z9 ... pe=msexcel

Hey Andy, what power mods are on the car if any?

O2 sensor looks intact, it's responding fairly well and in line with the rest of the fuel and air flow.

[andy_mac]

Just a Decatted downpipe, 3" catback, grimmspeed intake, custom front mount and 3-port solenoid

[andy_mac]

It seems to be low load where things get messy, is it possible the o2 sensor location isn't the best since all the restriction of the cat to slow the exhaust gases has been removed so its not quite reading correctly?

On/off throttle at low load seems to be where its hitting it extreme numbers.

https://docs.google.com/file/d/0B_0U1z9 ... pe=msexcel

https://docs.google.com/file/d/0B_0U1z9 ... pe=msexcel

[KiDo_Tuning]

If you have a real mechanical issue, whether it's a leak or some other problem, re-scaling the MAF should have no effect on it. As it will still try and correct for it either way, as AFRs won't be right.

Incorrect. Can alter the MAF scaling to correct for a massive vacuum leak BUT engine load will see say 0.5g/rev at idle instead of 0.2 to 0.3 depending on engine. Considering the BOV vacuum hose being off is enough for 25% and it is a decent cross sectional area hose, 15% is not much of a leak actually... MAP sensor hose being off can trigger +15 trims!

FPR reg vacuum hose torn for example can cause major fuel trims into the negative, as the FPR cranks from 36psi to 45psi which is a decent amount of fuel flow relative to manifold vacuum and ends up with huge negative trims even though it has a vacuum leak

[andy_mac]

Interesting. Did think you would be able to cover up a smallish leak with scaling.
So are you saying the idle load will only rise to 0.5 if you alter the scaling to get rid of the A/F correction numbers or that it should still show 0.5 at idle if there's a leak thats being accounted for in the A/F correction.
Mines 0.23g/rev at idle BTW

What do you think about those low load logs Matt? Is that kind of behaviour expected as there is less gass at low revs/load so it reacts slower?

[KiDo_Tuning]

Interesting. Did think you would be able to cover up a smallish leak with scaling.
So are you saying the idle load will only rise to 0.5 if you alter the scaling to get rid of the A/F correction numbers or that it should still show 0.5 at idle if there's a leak thats being accounted for in the A/F correction.
Mines 0.23g/rev at idle BTW

What do you think about those low load logs Matt? Is that kind of behaviour expected as there is less gass at low revs/load so it reacts slower?

Email sent
Yes, can cover up small leaks but do you want the fuel table to be leaned out on boost due to air not making it past the inlet valve when engine is on boost, we lean it out to get AFR's 'textbook' and then the leak is fixed at some point then runs leaner... not ideal

Exactly, 0.24 to 0.28 is normal on a 2L Liberty GT, so to be pulling fuel by 15% would make 2.3 a 0.1955 which is why I look for external influences first...

[alexeiwoody]

Just a Decatted downpipe, 3" catback, grimmspeed intake, custom front mount and 3-port solenoid

And I was going to say, what a great top end for a bone stock lib

Turbo seems a tad slow to spool. I'm assuming it's a JDM twin scroll.

It's also pulling some timing in the spool area, which isn't helping, but very minor stuff, could be just noise.

Incorrect. Can alter the MAF scaling to correct for a massive vacuum leak BUT engine load will see say 0.5g/rev at idle instead of 0.2 to 0.3 depending on engine. Considering the BOV vacuum hose being off is enough for 25% and it is a decent cross sectional area hose, 15% is not much of a leak actually... MAP sensor hose being off can trigger +15 trims!

FPR reg vacuum hose torn for example can cause major fuel trims into the negative, as the FPR cranks from 36psi to 45psi which is a decent amount of fuel flow relative to manifold vacuum and ends up with huge negative trims even though it has a vacuum leak

Incorrect, like your argument last night?

"Quad AVCS will work on single AVCS ECU....But only if it's a single AVCS engine!" Purposely misreading comments, just to nitpick and say "incorrect!" is getting a bit repetitive dude.

You yourself just pointed out that a discrepancy would show up elsewhere once you rescale. Also you'd be able to see when you're rescaling the MAF too far from normal. Or do you tune only using fuel trims in the LV...?

A pretty funny response, considering you used to rescale my MAF every other revision for no reason, when you couldn't think of anything else

[andy_mac]

Yea JDM twinscroll. Can definately notice the lag the extra piping from the front mount gives. Sure there's still some wastegate trickery that can be applied to make that a bit better. Think its still cracking open quite early from memory, haven't really been paying much attention to the wastegate table recently. Could probably get it spooling quicker if going WOT from closer to 2000rpm too, but not really a fan of giving it the beans from that low.

Got a new revision from Matt tonight so that hopefully sorts out a few of the issues.

[alexeiwoody]

Yea JDM twinscroll. Can definately notice the lag the extra piping from the front mount gives. Sure there's still some wastegate trickery that can be applied to make that a bit better. Think its still cracking open quite early from memory, haven't really been paying much attention to the wastegate table recently. Could probably get it spooling quicker if going WOT from closer to 2000rpm too, but not really a fan of giving it the beans from that low.

Yeah absolutely, can try tightening the WG/boost etc. a bit and see if it helps. Could be something else too. I was expecting it to be on full song 300rpm earlier at least.

Got a new revision from Matt tonight so that hopefully sorts out a few of the issues.

I bet he changed the MAF scaling...

[dr20t]

Check your front mount for leaks

That's way slow spool for the mods. Should be around 2800rpm all in

[jslayz]

Tighten, tighten, tighten!