2010 VE SV6 SIDI Manual

I havent seen a dynograph for a stock SV6 SIDI (did a quick google, apparently Street Commodores Nov11 issue has a graph in it. Anyone seen it?), but going by Holden's website:

Peak torque kicks in at 2800rpm (350Nm), and
Peak power hits at 6700rpm (210Kw)

Ok, the general rule is that the powerband of an engine lies between peak torque and peak power... but this is further constrained by gear ratios applied to the engine itself.

Anyone got gear ratio's I can use for calculations? And an accurate dynograph would be nice too .
If I had those I'd be able to calculate an ideal shiftpoint no worries to within a 100rpm.

But in the absence of these, it's anyone's guess. I'd place a hefty bet that the torque curve on the standard block is pretty flat considering how early peak torque is recorded, and most likely drops off before 5000rpm because of the target market (mums and dads that drive like miss daisy and change gears at 2000rpm), with the idea that good torque down low and mid range with better fuel economy is more important than a higher peak torque up higher in the rev range that would utilise more fuel to chase it. That's why car tuners are in business... to unlock that potential using more aggressive timing and ecu tunes (with little/no regard to fuel consumption ).

I reckon the stock block will actually perform better at lower revs.... and consequently revving the crap out of it wont give you any performance increase (might even slow you down actually!). Peak torque is at 2800rpm. By 5000rpm I reckon it's dropped off quite a bit. Yeah power keeps rising until much later, but everyone should know by now that the sinking feeling you get in your seatback when you press the go pedal is TORQUE, not power. I reckon once you're in the early 4000's there would be noticeable drop in torque, and it would be more beneficial changing then- than trying to chase more power at the expense of torque further up the rev range to 5000 and beyond.

Someone give me an accurate dynograph (I dont care about the figures- which can vary greatly between different dynos anyway, just the actual graph itself showing Nm & Kw relative to rpm), and exact gear ratios (auto and manual). Best guesstimate right now though? Mid 4000's... no more.

Remember, the stock SV6 isnt an F1 race car. Higher revs with restrictive breathing and gentle tuning of a stock SV6= waste of fuel and no performance increase.

 

MY 2010 3.6L SIDI Torque Curve

I have the power and torque curves for the 3.0 and 3.6 SIDI engines within a pdf file.

Unfortunately I cannot download it to the forum at work, so will have to wait till I get home late tonight.

Torque rises from about 260 NM at 1.2K RPM to 295 NM at 2.0K, then the line steepens to 335 NM at 2.4K, levels out a bit to 350 at 2.9K and then remains between 330 and 340 NM until about 5.8K RPM.

The source of this data is a holden Product Information Sheet of September 2009.

 

In addition, the above information is based on using 91RON fuel.

The same engine using higher octane fuel in the USA delivers 214.85 KW at 6.3K, and 364.50 NM at 3.4K. Maybe the Australian version would too, or the reduced figures in Oz could be set in the engine computer. I don't know the answer to that, though the Holden brochure does say slightly more power/torque might be available if using higher octane fuel.

 

Two things - make sure you've timed the clutch release, gear change and accelerator squirt perfectly, but let the revs drop more before carrying out the aforementioned.

 

I'd be VERY interested to see these charts mate. They would be a terrific reference for those that own the SIDI engines here.
If you could post them it would be very much appreciated.

 

Ok here we go!!

Fekason just emailed me the graphs for both SIDI engines (the 3.0L and 3.6L), big thanks to him!
I've combined the torque and power graphs for each engine into 1 jpeg for easy reference (just a cut and paste with MS Paint to line up rpm graph lines)

Here's the 3.0L http://imageshack.us/photo/my-images/820/30lsidicombined.jpg

And here's the 3.6L http://imageshack.us/photo/my-images/267/36lsidicombined.jpg

I'll have a better look at them once I get some definite gear ratios (auto and manual) for both engines, but looking at them very quickly I reckon pushing the 3.0L past 5300rpm is a waste, and for the 3.6L no more than 5700rpm. Both engines are running out of puff at these points, but it's nice to know that these little blocks like to rev! (even in stock form)
They obviously have a lot of room to be 'unlocked' with more aggresive tuning, but I guess Holden wasnt looking for straight out acceleration with these guys. Fuel economy was number 1 priority.

If I can get some accurate gear ratios, I can plug them into an excel spreadsheet I have and it'll spit out the exact rpm drop in each gear... which will give me a more acurate range to work with.

 

Auto gear ratios (both 3.0 and 3.6L SIDI):

First: 4.07
Second: 2.37
Third: 1.55
Fourth: 1.16
Fifth: 0.86
Sixth: 0.67

Gear ratios for manual (3.6L SIDI only):

First: 4.48
Second: 2.58
Third: 1.63
Fourth: 1.19
Fifth: 1.00
Sixth: 0.75

Final drive ratio for both auto and manual V6 is 3.27.

 

bump.......

 

thanks for bumping Xonar, forgot about this thread!

3L sidi-
rightio... using the above ratios (auto) and dynographs, changing gear at 5500 would be best. I'd probably aim for just before it actually, 5400 even. If you do, changing into the next gear down gives:

3200 RPM 2nd gear entry revs
3590 RPM 3rd gear
4110 RPM etc
4070 RPM
4280 RPM

torque starts to drop off before 5400, but it's still as high as it was at 4500 all the way to 5500.... however any higher on the revs would mean more loss in torque.
the very best part of the rev range is between 4500-5200, so you want to already be in gear and ready to go just before, during, and just after, as that's where your best acceleration is going to occur.

for the 3.6L sidi.....

 

well... she likes to rev a little harder- but torque drop off is much more pronounced once you reach shift point, so it'll penalise you big time if you push too far up.

5700... no more (maybe even 5600).

Changing at this point brings you into next gear as follows:

3280 RPM 2nd gear
3600 RPM 3rd gear
4160 RPM etc
4780 RPM
4270 RPM


now remember.... these ratios arent made by holden purely for acceleration from standing start. they also want the best fuel economy at common speeds we travel in australia (like 60, 80, 100), and also when you'll most likley want power on tap ready to go (for instance when you want to overtake). the holden boffins arent silly. they know if you are sitting at 100 behind a campervan and want to overtake, you want to put your foot down and be at the exact right spot on the tacho for instant power.... even if this means that straight line acceleration from a standing start suffers a little when compared as a whole gearset.

for instance, when you mash the pedal and the car drops back to 3rd gear on the auto (both 3L and 3.6L) at 105.6km/h, its exactly at 4200rpm.... smack bang perfect spot to be in the rev range when you want to acclerate hard all the way to 130ish (what tends to happen when you overtake, and then back off). so, whilst 3rd gear could be a little shorter when compared to 2nd and 4th for straight line acceleration off the mark, for real life driving at certain speeds.... its perfect.

also, look at the torque curve on the 3.6L. look at the big torque boost between 2000 and 3000rpm.
want to know why that's there? so when you're sitting in 5th gear at 110km/h it doesnt have to hunt around or struggle for power on small hill rises like the 3L does.
and that's also why the 5th gear on the manual is so much shorter when compared to the auto 5th gear. with the auto, it's not much of an issue to drop to 4th, but in a manual driving in 6th.... dropping down 2 gears on every hill at about 110km/h would suck.

long story short, my point is that whilst you can set a certain rev limit to take advantage of engine dynamics.... you are still limited by the gear ratios given to you by holden.
both engines can be 'unlocked' for more power/torque in a narrower range, but then without changing gear ratios (or diff ratios to limit the penalties somewhat) you may find that even though you have higher maximum torque and kw on a dynograph for bragging rights, your actual daily driver experience may be worse off because now you have less power and torque in other areas of the rev range for normal driving.
factors most people dont consider when playing about with more aggressive tuning etc.