Tuning a VT V8 ????

Post by **Holden202T** » Sun Jun 05, 2011 11:33 pm

So my brother has a Series 3 VS V8 Ute which is effectively the VT V8, maf, roller cam, all that .....

Its been fitted with a 355 stroker kit, slightly higher comp, some unknown cam other than its a "215kw cam" and a decent exhaust. Oh and blue top magna injectors.

So when he got the car it had a stock tune in it and was pretty reasonable (this is pre stroker) all i did to it was change the desired idle and sorted the IAC steps via the butterfly .... at the same time i put the CNPD realtime code into it mainly so i could change stuff on the fly but also cause its the HSV tune and it seemed to make a difference!

So its running that same tune and now has the stroker kit in it, i want to get the tune more dialed in and one of the things i wanted to do was to get the injector constant right as it was still the stock figure .....

my main concern is that when i changed it to get the numbers ok at idle then its lean up higher in the mg/cyl and rpms .... but similarly if the number is put back to stock its rich at idle and better up higher ..... and i know the injrate needs to change as the injectors have.

so then i started looking at this injector constant offset table, it looks to be the sort of thing that might cure my issues, but im not really experienced on this maf tuning and want to find out if changing this table is the wrong way to go about it all ?

if i use blms to offset this table i am getting some fairly significant changes in values which makes me wonder if this is wrong or not ?

anyone that has some experience i welcome your input!

Post by **delcowizzid** » Mon Jun 06, 2011 12:20 am

as far as i know thats pretty much the ve table for finer adjustments what sort of values are you ending up with in there.watch out some hsv vt's had a larger maf too

Post by **yoda69** » Mon Jun 06, 2011 7:14 am

HSV used a larger MAF on the 5.7 than the 5.0 litre.
Try and change the MAF tables to match the MAF fitted.

yoda69

Post by **Holden202T** » Mon Jun 06, 2011 8:50 am

i will look into the old and new tune differences and let you know if theres any variations in the maf tables etc ....

this is the differences i am seeing from just one log of blms.

stock:

with my blm changes applied as a percentage:

Post by **The1** » Mon Jun 06, 2011 9:34 am

i maybe going about this all wrong but atm i just set the inj const to the real inj flow you calculate from kinjflow utility, then tune the maf to get it all right, the pain with maf tuning is you can't do it realtime as you need to edit scalars and tables to change something, the reason i do this is so that if you go and slap some other injectors in they you should just be able to recalculate the base inj flow and change it and away you go, though i havn't proven that yet.. At the moment i setup a history table, maf hz on the left then long term fuel trims on the right, once your stft's come close to 0 then use ruffly half % to change yoda's maf table spreadsheet then go and update your tables then repeat all over again to fine tune. If there's an easier way id like to know

Post by **delcowizzid** » Mon Jun 06, 2011 10:42 am

im yet to find any injectors that justplug and play nice the 60lb seimens are close but still noyt just as easy as swap injector size and away you go.every injector has flow variations and different opening and closeing speeds etc that make them funny to tune even the way battery voltage effects them needs tuned into the tune this VT maf shit sucks to tune like all maf tunes do 808 the fucker and fit a vs s1 dash allready

Post by **The1** » Mon Jun 06, 2011 10:48 am

Post by **Holden202T** » Mon Jun 06, 2011 12:15 pm

delcowizzid wrote:this VT maf shit sucks to tune like all maf tunes do 808 the fucker and fit a vs s1 dash allready

I'm not sure thats an option my brother is going to want to take! and for the records its an auto so 808 is not as easy

Post by **Holden202T** » Mon Jun 06, 2011 1:04 pm

ok i've done a little compare of the original tune that was in the car (CJYN) with the current one (CNPD) and all the maf tables are identical as are injector constant etc .....

main changes are around tranny performance and such, aswell as some spark and a little bit of offsets in the injector constant offset table but i'm talking like .005 differences .....

Post by **The1** » Mon Jun 06, 2011 1:23 pm

oh yeh didn't know it had the inj rate table, thought it was like vs v6 and didn't have one, the table should just work like lambda figures shouldn't it?

Tuning a VT V8 ????

Tuning a VT V8 ????

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Re: Tuning a VT V8 ????

Re: Tuning a VT V8 ????

Re: Tuning a VT V8 ????

Re: Tuning a VT V8 ????

Re: Tuning a VT V8 ????

Re: Tuning a VT V8 ????

Re: Tuning a VT V8 ????

Re: Tuning a VT V8 ????