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LGT AVCS Tuning Discussion


Infamous1
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Thanks guys. I made some adjustments to my AVCS table(close to the 1st post table) and the car is running and building/holding boost better. I'll play with it a little more, but I'll be installing my 20g Zilla shortly; so everything will change again at that point.
Let's kick this pig!
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  • 1 month later...

Alright I've run out of things to tune on my car, so I'll take a look into this.

 

Power mods:

 

- UP/DP/TBE

- Perrin TMIC

- PE 850 injectors

- AVO fuel pump

- E85

- Romraider tune

 

Notes:

 

- Stock VF40 & stock intake w/ OEM paper filter

- 5300ft

 

Here is my table. I wouldn't know what to change on it.

 

http://beeez.com/lgt/AVCS.jpg

My '05 LGT

My '07 Supercharged Shelby

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I wouldn't get too wild as you still have the vf40 hotside. Turbos with bigger hotsides are where you will benefit from more advance, headers as well. Best way is to set it at different degrees (ie: 20,25,30,35,40) and check acceleration. Keep tabs on boost, afr, and engine load. Really need to only test those out to about 4K rpms at that point you will be going backwards and almost certainly loosing power. From about 4k-6k rpms try 15,10,5,0 degrees. Once again remember the more advance the lower the output and higher the EGT's up top.
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Haven't done indepth testing, but I've messed around with mine some (upping it in the 1600-3200 range), and really haven't gotten much of a difference in 50-80 mph and 60-80 mph times (3rd gear pulls). I'm VF40-18G (TDC tuning special) with MR Headers, CBE, UP, DP, etc.
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Haven't done indepth testing, but I've messed around with mine some (upping it in the 1600-3200 range), and really haven't gotten much of a difference in 50-80 mph and 60-80 mph times (3rd gear pulls). I'm VF40-18G (TDC tuning special) with MR Headers, CBE, UP, DP, etc.

 

It is going to be hard to notice the difference in your 3rd gear 50-80 times as the turbo is mostly spooled by then.

 

Use the accel tab on airboy's sheet.

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  • 3 weeks later...

According to Clark USDM cams stop at 30 degress. Putting more than that does not make difference unlike JDM. However, USDM 2007 STI stock map has AVCS set up to 32 degrees, so perhaps the limit is 32, or 2007+ changed.

 

Good thread.

 

Here is mine.

 

FWIW bigger turbo = more AVCS. (over-simplification)

 

 

AVO380

AEM CAI

Perrin TMIC

Aquamist HFS-5 alky (50/50) 550 cc/min

3" TBE w/ HFC

iON UEL headers/UP (coated)

 

and other stuff that doesn't matter.

 

http://i248.photobucket.com/albums/gg194/littlebluegt/AVCSalky500.jpg

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Well, according to my logs my cams will go to 45 degrees.;)

 

I think it may depend on if one is referring to crank degrees or cam degrees (factor of 2 difference).

 

Ok, settings above 30 (or 32) in AVCS tables according to him do nothing on USDM motors.

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Ok, settings above 30 (or 32) in AVCS tables according to him do nothing on USDM motors.

 

Link to where he said this?

 

Physically, it's not true. There's a stop but it's not at 30 degrees AVCS.

 

He may have meant that there is no benefit to cranking it above 30.

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Link to where he said this?

 

Physically, it's not true. There's a stop but it's not at 30 degrees AVCS.

 

He may have meant that there is no benefit to cranking it above 30.

:whore:

That also is strange since I have "heard" he uses s203 and s204 AVCS values out to 6000rpm for his tuning which rum more than 30 degrees.

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I have no clue. The question is - does he have no clue as well, or LGT AVCS is different from STI :confused:

 

No, they should be the same.

 

Somewhere in Nasioc, or some other Subaru enthusiast/idiot site:lol: someone took measurements of the cams, and what angle they will go to. He found that there is a stop, and thought it was at 30 degrees. I read the thread, but can't even remember what site it is on.

 

I think there was some confusion in his measurements though.

 

Clark contributed to that thread.

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I did some testing today (just starting to tune my new WBR header) and found out some stuff you guys may want to see.

 

This is 0% WGDC tuning right now.

 

Yes, you are welcome for taking the time to graph it out.:)

 

 

I did a few map revisions to test whp on different settings, I was seeing a bit of a trend. This is backed up by 6 other logs, they were almost all identical, some temps, same road, within mins of each other (and yes, I only kept the logs w/ the headers warmed up, although with my wrapped headers it did not make a noticeable difference like before).

 

MRP between the two runs, identical:

http://i248.photobucket.com/albums/gg194/littlebluegt/AVCSMRP.jpg

 

MAF between the two runs, slightly less on the higher AVCS setting:

http://i248.photobucket.com/albums/gg194/littlebluegt/AVCSMAF.jpg

 

AVCS degrees between the two:

http://i248.photobucket.com/albums/gg194/littlebluegt/AVCSdegrees.jpg

 

WHP between the two runs, the lower AVCS settings made more power here:

http://i248.photobucket.com/albums/gg194/littlebluegt/AVCSwhp.jpg

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Hmmm, very interesting. Thanks for posting. The AVCS continues to be "illusive". Maybe if we did a bunch of tests changing timing and AVCS...I don't know. Maybe it simply doesn't change things much, unless you, say, get it way too low (give that a try ;-)
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Hmmm, very interesting. Thanks for posting. The AVCS continues to be "illusive". Maybe if we did a bunch of tests changing timing and AVCS...I don't know. Maybe it simply doesn't change things much, unless you, say, get it way too low (give that a try ;-)

 

Obviously with a dyno you can do this a lot easier, but with time it can be done on the street to.

 

Always try for maximum VE, timing is a crutch, as in if you can get better power with a different AVCS setting do that, even if it means you have to take some timing out.

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