Twin Turbo Tuning probelms

[Picto]

Hi all.

I'm tuning up a twin turbo SS commodore which i seemed to be having a few issues with. I have done forced induction cars before but only one turbo. I'll give you a run down of the vehicle as i know information is king!!

VE built 408ci motor[LIST]
Forged dish pistons
Rods
Steel stroker crank
STD heads L98
STD manifold L98
60lb injectors
comp at 10.3/1
9lb boost
Std gear box with a converter
Std diff gears
Electronic E-boost controler
No fuel system yet as money was sort and was told to restrict to 500rwhp

No the car feels a little average on the road to drive i would have expected a little more. on the dyno it only pulls around 430rwhp to 5000rpm and falls in a big hole as you'll see by the attached dyno graph. It is a consistant thing and repeatable every run. I didn't feel it on the road but. It seems like its hitting a limiter but just can't find it. It does start to recover but i always get off the gas sortly after this has occured. One thing i did notice is that injector duty falls away but does not recover. Maybe i am hitting a torque limit somewhere that i can't find.

I will post the latest engine and box tune.
Only other thing i could think of is maybe i haven't set the boost controller up right but might explain low down boost but boost is consistant throught the run!!

To anyone how offers advise and help i thank you in advance.9972
9971

I will upload logs and dyno later tonight

[swingtan]

Also post the logs.

Any reason you went 10.3:1 CR when you knew you were going FI? I'm assuming you decided on a higher CR and then run lower boost to reduce any down low lag effects.

Simon.

[Picto]

I wasn't involve the the motor combo just got given it to tune!! i will post them soon when i get home. Anything would would like to see??

[Tre-Cool]

with those cube's and injectors. your very much at the limit of the stock fuel pump supply. trust me. tell the owner to cough up the extra $$$ and buy the vcm dual pump tank. i run that in my brothers ve-tt and used to have one in my own ve. now i just run the kpm dual pump one (long story, but your much better off with the vcm setup).

with the stock pump in my cammed/blown ve 400rwhp was pretty much the best i could go before it started to lean out (tuned for flat 12's, and you could feel it fall on it's face.)

my ve makes 380rwkw with flat 12 afr's and 400rwkw with some methonal assistance. :-)

ok. taken a look at the tune and um.... You need to stop right now...

The fuelling is messed up. what afr's are you running in this thing? coz from what i can see your not entering power enrichment and even if you were your still commanding stoich.

please dont tell me your tuning off the IVT temps alone. (b0146)

[Tre-Cool]

okay, not sure if you have realised this but there is no 2 bar map sensor setup on this tune. instead what appears to be a 1.5 bar. I'm guessing your still running on the 1bar VVE table?
your pe & none pe fueling is up the shit, so i have put some reasonable fuelling values in. i.e 11.8 afr's. at the moment you are slowly commanding back up to 14.7afr!
knock sensors way to desensized, leave the stock settings for now and see how you go
i've dropped the rev limit to 5k rpm coz theres no way in hell your gonna make power with the current fuel system past that point
ETC throttle rate limits adjusted
torque control parameters
power & minimum spark reduction tables
cold engine noise reduction table
PE fueling and non pe
turned off dfco and turned off closed loop, im guessing single turbo, so O2's are going to be useless anyway
All the open loop tables

let us know how you go

[Picto]

I must have been having a blonde moment yesterday becuase that wasn't the file out of the car. Ok I'm running mafless 2 bar, i have checked to make sure that map reads 100kpa at key on, throwing maf code 102 as well. I still think that my IVT's are up the shit i'm going out to do some more logging today to hopefully clean it up a bit more. I have taken your PE settings and taken note and changed a lot through the tune to what it was, what i have posted is going in the car today. The car is twin turbo as well.



9980

[Tre-Cool]

so is this maf or mafless? if it were me i would just go mafless with the auto. we dont have too many drama's with dynamic fuelling with the auto's. if it were manual then i'd stick with the maf.

just looked at updated tune. looks like mafless as the maf signals are set to fail.

[Picto]

Running mafless due to being auto. that was the same advise i was given

[johnv]

Does it have a desent set of valve springs, if not valve float may be an issue.

[joecar]

I don't see the attached dyno graph...?