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347 cubic power!
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171 Posts
Discussion Starter #1 (Edited)
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).
 

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347 cubic power!
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171 Posts
Discussion Starter #2
I wouldn't mind trying to calculate and plot the torque graph as well. I have a note which says that:
HP = RPM x T(torque) / 5252

Therefore:
T(torque) = HP x 5252 / RPM

Note that torque will be in ft/lbs. Is the original formula correct? Does 1 ft/lb = 1.356Nm?
 

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100MPH Hunter
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1,045 Posts
Hey Slipper,

Why didn't you go the 2031 cam. I thought these were a better option with the new 1.7 roller rockers.

And

If you wouldn't mind PM me with a rough price, as this is what I will be doing very soon, except maybe with the above!!!

Cheers
 

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AU XR8 I - OWNER NOW!
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33 Posts
hey slipper, what ratio are your roller rockers? are they the origonal or other & did everything just on.
 

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347 cubic power!
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171 Posts
Discussion Starter #5
TwinPiston said:
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.
 

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AU XR8 I - OWNER NOW!
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33 Posts
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.
 

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AU XR8 I - OWNER NOW!
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33 Posts
thats some nice power from your car 190kw @ the wheels, torque is 341ft/lb @ 4000rpm is that correct? not to bad.
 

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AU XR8 I - OWNER NOW!
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33 Posts
i had a xd 351 426hp, [email protected] wheels & 410ft/lb, [email protected] 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.
 

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347 cubic power!
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171 Posts
Discussion Starter #9 (Edited)
xdv8 said:
...torque is 341ft/lb @ 4000rpm is that correct?
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.

xdv8 said:
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.
 

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AU XR8 I - OWNER NOW!
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33 Posts
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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boosted sleeper
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4,575 Posts
This may sound like a stupid question, but will a CC2030 be ok to fit into a bottom end that has 168,000 k's on the clock and ported and cleaned up E7 heads, ported intake, 65mm tb, CAI, full exhaust system?

My motor doesnt leak or damatically burn oil. Reason why I ask is that if I can get away with it for a while I will before I pull the motor out for a rebuild. Will it cause extra stress on the internals? Would I be better off getting a bottom end freshen?

Opinions please!
 

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OFR #7
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322 Posts
I've been thinking about the same thing on my 150K 5.0L.

I coming around to thinking that if your going to do a cam change you might as well pull the engine and do a complete freshen up.
The cam, heads and other mods won't kill your engine if fitted (provided you keep the comp to a reasonable level), it will still be up to how you drive and maintain the car.

Like I read somewhere, If you modified the the engine at 5,000km would you pull these mods off at 150,000km because they might kill the engine, I don't think so! It all depends on the condition the engine is currently in.


Mick
 

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boosted sleeper
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4,575 Posts
Well, I dont thrash the car like theres no tommorow, but I do give the car a run off the lights when needed. I would only bring the cr up to 9.0:1-9.2:1 no more. I religiuosly change the oil at 5000k intervals and full service every 10000k. I maintain the car regularly, not leaving anything to chance. But then again, doing a head & cam upgrade maybe taking a chance with 168,000k's on the board!
 

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XR8 Owner
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545 Posts
blueoval said:
Well, I dont thrash the car like theres no tommorow, but I do give the car a run off the lights when needed. I would only bring the cr up to 9.0:1-9.2:1 no more. I religiuosly change the oil at 5000k intervals and full service every 10000k. I maintain the car regularly, not leaving anything to chance. But then again, doing a head & cam upgrade maybe taking a chance with 168,000k's on the board!
well i was going to drop in a 2030 into mine when it had 191,000 on it. One of the main problems in the end was that the pistons had to be notched because the cam had too much lift. It's fine in the au's (dunno bout ef or el's) because they have different pistons. I'd talk to your mechanic bout it. I ended up with a complete rebuild....
 

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XR8 Owner
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545 Posts
and on the subject of servicing, unless you either know the person who owned the car before you or have owned it its whole life then you don't know how often it was serviced or how it was driven. On inspection of my motor when pulled apart it had had the absoloute crap thrashed out of it...
 

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boosted sleeper
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4,575 Posts
true sikED, but it gives me piece of mind knowing that I do maintain it on a regular basis. I dont claim to know what history the car has. All I know is what I have done to it and what I intend doing to it. Going by how the car currently performs and drives it gives me an approximate idea of its condition.
For all I know, my car may have been thrashed like hell also before it came into my hands. I dont know. I'm doing my part to look after the car the best I know how and thats what I will continue to do.
Until I pull it down for a rebuild, I'll just drive it as is.
 

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Two SC 61's = trouble
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6,360 Posts
So long as it's got decent oil pressure and not much blowby/ oil use she'll be o/k...!!!
 

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Registered
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670 Posts
i got a 14.4 on a warm humid night with the sister 2031 cam (made for 1.7r/r)
 
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