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Just wondering if an oil catch tank would allow me to run more timing?

(Oil content / vapor supposedly increases detonation likelihood .. ?)

Does this depend on the engine's blowby / wear/tear or does it help in any case?

Thanks ..

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Yes, that was exactly my point/question.

Oil vapour reduces octane rating .. so I thought the catch tank might help.

Well oil/oil mist in the comustion cylcle is an octane reducer, so knock is more likely to happen...

Sorry for not making this clearer, please see below/above posts..

Cheers!

what?

timing affects combustion of the engine, it has nothing to do with the blowby or lubrication system

This theory is a bit odd to me

Edited by Torques

You'd need to be breathing a fair bit to have a major impact in that regard when talking your average street level application.

At street performance level best you'd be talking a degree/two of timing which you'll never notice really and any tune should be safe enough to accommodate that anyway

Catch can (proper one with baffles) is always a good idea regardless

Assuming the car was tuned with a certain amount of blowby, and assuming that that amount of blowby oil was enough to require a little timing to be (notionally) taken out to prevent it pinging, and assuming that the catch tank will sufficiently reduce the oil return to the charge.......then yes, you might be able to add a degree.

Thanks,

So one degree or two is definitely not worth the effort then, especially since my engine is quite healthy.

If we were talking five degrees or more it would have been a different storry,

How much oil do you guys find in the catchtank anyhow?

It's not vast amounts, is it?

You'd need to be breathing a fair bit to have a major impact in that regard when talking your average street level application.

At street performance level best you'd be talking a degree/two of timing which you'll never notice really and any tune should be safe enough to accommodate that anyway

Catch can (proper one with baffles) is always a good idea regardless

Edited by Torques

Alright,

I think I got the point :)

Assuming the car was tuned with a certain amount of blowby, and assuming that that amount of blowby oil was enough to require a little timing to be (notionally) taken out to prevent it pinging, and assuming that the catch tank will sufficiently reduce the oil return to the charge.......then yes, you might be able to add a degree.

What if......... Say I said........

I have seen a turbo V8 that after cleaning the inter cooler piping from all oil residue (due to poor crank case ventilation) and cleaning carbon deposits of the tops of pistons we where able to dial in 10 degrees more timing...............

I think if you're building an engine to make as much power as is needed to start worrying about oil vapour separation and the potential consequences of not separating it, you'd almost be negligent to not be seriously thinking about either E85 or WMI. They both equal pretty much free power. So once you get past the point of running stock injectors and turbos and all that jazz, and start having to buy new bigger stuff, you'd be much better off designing your system around one of those options anyway.

That's just my 2c, marginally related to the original topic as it is. The point is, the effect of oil mist would be greatly reduced by running E85 or WMI, as you wouldn't get anywhere near as much carbon. Your test would have been better (scientifically) if you'd left the carbon behind when you cleaned out the oil and tested how much extra timing you might have gotten just from reduced oil. Then cleaned out the carbon and gone back again. More cost and trouble obviously, but that's the usual problem when you alter 2 variables at the same time. It's hard to tell which one was responsible for the change.

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