Some of my waffle has already appeared in a "Crane Cams 2031" thread, but I thought that I would start another to avoid confusion.
I have made the following mods to my AUII XR8:
* Crane 2030 cam (p/n 444221) complete with springs / retainers etc (kit p/n 44308-1)
* Rollmaster timing chain
* A cleanup of the stock GT40P heads, raising the comp ratio to 9.7:1 (valves remain AUII stock)
* Installation of AUIII (220kW / 70mm) throttle body
* Pacemaker tri-y extractors (p/n ph4001)
* 2 x 2.5" exhaust system similar to AP's old machine (search thread "AU2 XR8 Stroker Exhaust System Buildup")
* Unichip management
When I first got the car back, it felt strong but not as "crisp" as I would have liked. The worst bit was the fact that it was obviously running very rich, especially at it's somewhat cranky idle.
After the Unichip was installed, the tuning leaned the engine out a bit (see graph) and the power went up. Better yet, the idle is smoother - though it is still very obviously non-stock. Despite the mean sounding 900RPM idle, the car is very tractable at low revs. Perhaps there is still a bit of fine tuning to be done, but I am very happy.
I have attached a couple of dyno sheets FYI. The red line on the first graph is pre-unichip/tune (ie rich running).
Why didn't you go the 2031 cam. I thought these were a better option with the new 1.7 roller rockers.
2030 is designed for use with 1.6:1 ratio rockers, whilst the 2031 is designed for use with 1.7:1 rockers. AUII XR8s have *1.6* FMS roller rockers from the factory (well, Tickford at least) so I thought that I may as well use them and save myself some money.
The 2030 has less advertised duration than 2031, but more (on inlet) when measured from 50 thou. The 2030 also has greater lift than the 2031.
If you were to use the 2030 with 1.7 rockers, you would certainly have heaps of lift - but you would also probably have piston / valve clearance issues, especially if you were looking at milling the heads for more compression.
thank you, ive finally got someone who knows what there talking about. i have an auxr8 I & have been trying to find out what fits what & the differences between the I II & III'S. i couldnt work out why the cams in the 3's were the same as the 165kw eng eb (i have a parts cataloge loaded at work to look up parts for my car) & to x reference the numbers.
i had a xd 351 426hp, 310@ wheels & 410ft/lb, 395@ wheels so i miss the grunt but the xd was like a go kart compared to the ride of the au. have 1.7 non adjustable yella terra bolt ons, 70mm au III throttle body, herrod mandel intake tube, ss coldair intake & k&n air filter ready to go on & i'm just trying to sus the exhaust,cam & heads. so thanks for your facts & figures cause ive got pages of it & thats what i'm into.
I just added the numbers to a spreadsheet using the torque from HP/RPM formula above. Peak torque at the wheels is 384Nm (283fb/lb) @ 3900RPM. You cannot read the torque off the second graph - that is just the load applied by the dyno.
There is a little dip in torque between 3400-3800RPM which is just noticeable on the power curve as well. Might need a bee's dick of extra fuel / spark here - but I don't think I'll lose too much sleep over that! Check my torque vs power graph.
Originally Posted by xdv8
thanks for your facts & figures cause ive got pages of it & thats what i'm into.
I like to crunch a few numbers myself... I've got a lot out of this forum so I hope you do too.
i thought the torque curve was a bit flat in that other graffe, be a gun motor if it held the torque like that! i'm having net problems slows down after 20m and then cuts me off so i'm sorry my replies are all over the place
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