E39 GMH 3.0 SIDI: 91 vs 98 Octane

[GMPX]

Considering stock they average around 13.0 - 13.5L/100 city cycle it's not the car to buy if economy is on your mind. Sorry but I feel it's a poorly thought out engine with a dreadful torque curve and therefore it should not be in something that weighs as much as a VE, they should have only offered the 3.6L which at least doesn't have peak torque up near redline.
It's been shown in many tests the FORD 4.0L gets better fuel economy than the 3.0L SIDI. And if the answer is to use 98 Octane to get better performance (which I agree with) it's missed the point of it's original intention, 90% of these will be run on discount supermarket fuel, Holden would have known that.

[swingtan]

The wifes car is on an average of 11.8L/100KM after close on 9,000 KM (she never resets the trip computer). This is with plain old 91RON and doing the average school drop offs and peak hour crawls with the odd long distance trip towing a trailer.

I agree with Ross though, the 3.0 is way underpowered in the big car. It's probably fine if you are only driving in 50KMH back streets, but it's just mot quite there. Sure, running E85 would help, as would 98 or E10, but if you get a fuel card that only allows 91, you are stuck. Tweaking does help, but this little motor really wants a couple of exhaust additions to really make it a good motor. That and the ability to achieve 100% TPS below 3000 RPM.......

[kangsta]

Yep, I agree with you guys. Unfortunately you cant get peak power with these without high grade fuel :(

Wonder how many stroker kits will come out once these things get a bit older

[swingtan]

hint.... Intake cam advance helps a lot

[GMPX]

That and the ability to achieve 100% TPS below 3000 RPM.......

That isn't what is annoying, if it catches itself in the wrong gear even at part throttle, slight incline you have a dead pedal until it kicks down two gears, no torque = busy transmission. The WOT performance is not my biggest complaint, it's the part throttle that is bad too.

[ScarabEpic22]

That isn't what is annoying, if it catches itself in the wrong gear even at part throttle, slight incline you have a dead pedal until it kicks down two gears, no torque = busy transmission. The WOT performance is not my biggest complaint, it's the part throttle that is bad too.

Have you cleaned the shift points up Ross? I did that on an Impala, reduced shift times a little, bumped the pressures, and it made a HUGE difference. The transmission would actually be in the right gear when you wanted it to be, think it had the 3.6 in it though.

[GMPX]

I moved on once I got the Cruze

[ScarabEpic22]

I moved on once I got the Cruze

Lol! Im hoping a Sonic is in my near future, need a little DD because my TBSS is killing me driving to work right now.

[3L SIDI]

The wifes car is on an average of 11.8L/100KM after close on 9,000 KM (she never resets the trip computer). This is with plain old 91RON and doing the average school drop offs and peak hour crawls with the odd long distance trip towing a trailer.

I agree with Ross though, the 3.0 is way underpowered in the big car. It's probably fine if you are only driving in 50KMH back streets, but it's just mot quite there. Sure, running E85 would help, as would 98 or E10, but if you get a fuel card that only allows 91, you are stuck. Tweaking does help, but this little motor really wants a couple of exhaust additions to really make it a good motor. That and the ability to achieve 100% TPS below 3000 RPM.......

^ i have SIDI 3L with custom xforce cat back exhaust plus the below custom SIDI extractors, on my old tune on BP98 it was shooting Quad flames on the race track & drags havnt put my EFI live base files from oz track on yet might try soon







GM tech 2 tool is indicating im only getting the standard 60% throttle on that tune running slightly too rich still at the high RPM range hope to soon get it fully dyno tuned with EFI live with the RPM vs TP table for a track tune maybe E85 flex fuel

[Boost]

hint.... Intake cam advance helps a lot

Would like to know more about this please. I thought it would cause overlap reducing overall power.