VR V8 custom spark advance

[calais5l]

Hi Guys,

I'm new to this forum but have been modding my memcal over the last year. Not sure if I've posted in the correct area.

Anyway, after testing various changes to the memcal for my VR V8, I have a question regarding the amount of spark advance that I am able to run.

Through looking at a few of the main spark figures that a few guys run on the forums, I find that I am not able to even get close to these custom tunes.

Quick details of the car.

- VR V8, completely stock engine internals.
- Single 2.5" Exhaust, TRI-Y Pacies.
- 95RON PULP, Base timing 10deg.
- New balancer

On a stock engine, what amount of advance should I be able to achieve on 95RON Fuel?

The 95-100MAP 400-4800 section i'm running now is:

4800 25.66
24.96
24.26
22.15
24.26
26.72
27.42
24.96
21.80
14.77
11.95
400 5.98

I'm finding that with these figures, I get slight pinging between 3600-4000 RPM. Even though the engine has the highest VE around this rev range, It seems as if I can only acheive a couple of extra degrees from the stock map when on 95RON.

Would this be normal on a stocker?

Thanks Guys.

[vnsswithcam]

have you got a log of the wot run??

ive had a situation where it sounded like it was pinging but when i loged it no knock was recorded it was another sound that sounded like pinging coming from somewhere else?? ive got this spark map on a stock 5 litre with try y genies before i recorded a knock on 95 ron anything after this it recorded a knock
4800- 29.29
28.13
28.13
28.13
28.13
27.07
27.07
24.96
23.20
22.15
18.98
400- 8.44
but every engine is different ive found??

but only due to the fact that i logged the run i ran this spark map and i dont know how your engine is internaly may have alot of carbon build up causing it to ping earlier?? or maybye you got a bad batch of fuel??

[Jayme]

yeah I aggree, you should be able to run that spark advance vnsswithcam has posted, I run somewhere round that in the v8's I tune and its always the goods. ive found big extractors, nice free flowign exhausts, and you can pull 29 - 30 deg round 4000rpm

[vn5000]

Are you sure the tdc mark on the new balancer is in th right spot ?

[Holden202T]

what afr's are you seeing at WOT ?

[calais5l]

Thanks for the replies all.

Unfortunately, I don't have a wideband meter, so I know i'm sort of running blind in the air/fuel ratio part of it. In terms of the VE tables at 95-100MAP, I am running a little less than the HSV 185 tune figures. Does it sound like it may be leaning out slightly at these revs?? Are the VE figures in the HSV tunes usually more than enough for stocker with K&N filter, extractors and exhaust? I've even changed the fuel pump and filter recently.

The engine has hardly been given a hard time for most of it's life, and even when logging the fuel trims with the stock memcal, the LTFT's are fairly close to perfect.

Cheers.

[Holden202T]

if you have logs post up a screen shot of narrowband logs at WOT ?

[calais5l]

Sorry to ask basic questions (i'm still learning), but can you log AFR's with the standard O2 sensor and ECU at WOT or do you need a seperate AFR meter?

How is it done?

Cheers.

[VL400]

You are able to log the narrowband O2 voltage on the standard PCM, while it does not give an AFR reading it can give some idea of if its running excessively lean or rich based on the voltage reading.

[calais5l]

Thanks for the info.

Well, I haven't had a chance to do a logged run with the notebook, however it looks like that my tune is a little lean at certain points after about 3200rpm. I adjusted the VE tables today and have taken the numbers up by only a few percent in the mid to high rev range, to run around the same VE numbers as the HSV 185 tune. Not only do I get no pinging, but I was able to add an extra degree or so of advance after 3200 and still have no pinging (feels noticably stronger in the mid range now).

I'll add a very small amount of advance each time over the next few days till I find a safe limit. I now see the importance of correct AFR's!

Only problem I have remaining is a noticable power deadband at around 2400-2800 which I can never seem to improve. I have run up to around 28deg at these revs with no pinging but also no increase in power. Will have to try cutting a few degrees incase i'm running too much.

Thanks again. It's great to be able to talk with many knowledgable guys on this stuff.

Cheers.