VXR8 pinking noise/slight rattle noise from exhaust?

[Sid123]

Hi
I have recently noticed a rattly/pinking sound when accelerating gently from, say, 1500rpm in 3rd/4th/5th/6th gear.
It's particularly noticeable with the driver's window open when driving next to a concrete barrier/wall so perhaps I haven't heard it over winter with the window shut.
I haven't had a car pinking for many years and wondered if this has anything to do with E10 fuel??
The car has only done 20k miles from new so I am at a loss to understand it...
Any thoughts?
Thanks

Edited by Sid123 on Wednesday 27th April 20:31

[Boosted LS1]

At light loads i'd be surprised if it's pinking unless there's a mapping issue. Could something be loose under the car?

[SturdyHSV]

Would also be very surprised if it's pinking / knocking, it has knock sensors and a low octane spark map designed to cope with far worse fuel than we get in the UK.

Unless it has a tune on that's perhaps removed the low octane map (as Wortec tunes seemingly have done in the past) or disabled the knock sensors, although still unlikely at light loads I'd have thought.

I had a rattle that was because an O2 sensor had loosened off a bit (which is amazing as normally it takes Thor to undo one), alternatively could be an exhaust bolt somewhere, heat shield has come loose, that sort of thing, my guess would be on something rattling rather than an engine issue

[Sid123]

Thank you.
It's an 09 car with a Stage 1 Wortec pack on it, but I'll get it on a ramp and see if there something loose underneath.

[astonman]

If you are running E10 it could be pinking due to a weak mixture.Any tiny airleak in the induction set up will be much more likely to produce problems on E10.
If you can't find the origin of the noise,try filling with Super unleaded and ideally use Esso Supreme 99 plus unleaded which is completely ethanol free in the southeast and midlands of England.

[vxr2010]

if it’s been tuned you should really be running it on SUL , tesco 99 or shell 99 work well , your car will run better , so that could be your noise

[SturdyHSV]

vxr2010 said:

if it’s been tuned you should really be running it on SUL , tesco 99 or shell 99 work well , your car will run better , so that could be your noise

To get the most performance yeah, he should run it on super, but if it's been tuned properly it should still work on 95 octane without the engine being subject to damage, in my humble opinion anyway.

Certainly sometimes driving to Le Mans etc. super unleaded isn't available, that shouldn't mean the car is then knocking and thus risking damage :shrug:

[vxr2010]

i agree with above , but was always told run on sul , it was noticeable when it was not as did not run as well , so the not running as well, could be generating the noise being heard , when i got my monaro over 10 years ago i was putting in 95 , it had the focus pack done by previous owner , it ran and performed noticeably better on 99 , if it was the map or it had always been run on 99 so was used to it i don’t know , but well worth the sul

[Sid123]

I'll try the Esso SUL and see if that cures it.
Thanks for all the input.

[astonman]

I believe that Esso supply Tesco.
So,the 99+ SUL at a Tesco in the southeast and midlands should logically be ethanol free.
If the Esso SUL does the trick,then next fill up at Tesco ( which should be less expensive) and see how it compares.

[vxr2010]

not all Esso's do the 99 sul , tesco 99 momentum is what i normally use , as shell 99 is more expensive with no extra benefits ,

[astonman]

I reckon Tesco 99+ octane will be pretty much Esso Supreme 99 plus unleaded but cheaper.

[Sid123]

Thanks all.
The more expensive petrol seems to have cured it.....you live and learn.
Also glad the plugs came out with no issus after 13 years in the car!

Edited by Sid123 on Friday 20th May 21:24

[SturdyHSV]

With so few mods, it should not be knocking tbh, the compression ratio, cam etc is more than capable of running on any old fuel without knocking / pinking, it does lend credence to some of the more recent skepticism about Wortec's maps...

Maybe speak to Luis Sola...

[fred bloggs]

SturdyHSV said:

With so few mods, it should not be knocking tbh, the compression ratio, cam etc is more than capable of running on any old fuel without knocking / pinking, it does lend credence to some of the more recent skepticism about Wortec's maps...

Maybe speak to Luis Sola...

Its likely it is an older map ,and ran close to the limit with the older 95 E5 , but is not liking the E10. Im sure wortec maps were fine, but if nobody has had a look at the tune for years, its not gonna be perfect.
This is the trouble with using older ecu's and maps without wideband closed loop and/or flexfuel sensers.

Ethanol isn't bad, if I could readily find E85 in the UK, id be running it, even N/a its worth about 5-10 % if tuned for it.
OP, if you got the map changed, Id bet it would perform exactly the same on 95E10 as 99e5, it just needs more of it.

Edited by fred bloggs on Saturday 21st May 11:55

[ninjasta]

The ls2 vxr8 manusl reccomended 98 ron pertrol. Closest in is the super now e5. Grade. The ecu should adapt by retarding the spark to the low octane map. If that isn't present it will need a higher rating. There basic scanner should to read the iso advance setting and knock sensors. Other you'll need eother HPtuner or efilive scanner to read the runtime operation. I invested an hp tuner setup after GM pulled of Aus and sold GM europe to stelantis. Which the the dealer stopped being V8 vxr apprved garage.