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VCT Tuning Territory NA conversion


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ok, just a recap on my motor combo. Built turbo motor , not like u think lol. Used factory turbo rods and pistons. Hand ported Fg head and fg cams, 4' dump down to a 3" exhaust with straight throughs. So It may be different on your setup. So please check for knock as this increases cylinder pressure at peak torque . May even bend rods and a visit from Mr Rodney in Na engines ( may have to really baby timing in those areas and find a balance?).

Ok a disclaimer , I'm a newb at tuning , so be warned and proceed with caution!

Righto  ! So my Terry is 2005 , which means it has the lovely btr with the loooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooogest 1st gear in histroy. This meant that in 1st gear it wouldnt come on boost till about 50 km. Not good for Chopping BMW's at the lights to the legal 60 k/hr speed limit! 

So through watching a utube vid (Bobby Mcboost) I picked up on tuning the VCT page.

So I add 3 deg through the 1500 to 4000 rpm tables from memory and hey presto ! was on boost at about 35 km?hr and low to mid range. Well I thought , " Well  more reated must be better !" 

It didnt make anymore differance , but knock was happening.  So back to previous setting, IVe been running E10 (94 oct ) as 98 is nearly $2 / lt Ive had to pull timing through the timing table even under .4to.6 load 1700 rpm and under boost . So check timing .

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4 hours ago, Roland@pcmtec said:

You can also add overlap to assist with spool and reduce dynamic compression so you don't have to run crazy retarded spark. 

Awesome, can u point me in the right direction please? What’s the Auf number ? 
I’ll have a play with . I’m guessing another 2 deg of overlap in the appropriate areas  

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8 minutes ago, Plumbs said:

Awesome, can u point me in the right direction please? What’s the Auf number ? 
I’ll have a play with . I’m guessing another 2 deg of overlap in the appropriate areas  

The main overlap tables. There are 2 of them, one is TPS vs rpm one is load vs rpm so make sure you adjust both. Depending on BF FG etc they have different IDs but they are easily found here.


Make sure to datalog the angles to ensure it really is hitting what you are commanding.

As you can see they already increase overlap drastically to assist with boost transition and reduce knock at low rpm high loads in most calibrations.


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15 hours ago, Plumbs said:

yep , B series the above table doesn't exist . When I upgrade to 1 vehicle workshop, I think I can upgrade to a bf strategy maybe ?

The table will exist in the BFs, it will just be a different ID.

However is this a BA? BA will require the F6 strategy to get full independent VCT control


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  • 8 months later...

hey roland. 

curiously, you mention adding VCT timing to the exhaust side of things. i did noticed on my NA+T that the BF NA has it, but the xr6t/F6 does not.  but as we move into FG they do. 

also the VCT/mbt spark multipliers. does it add the number 
eg : .2 at X rpm an load?

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