MX-5 SE owners, factory catch can question?

[PASHN8]

Just a quick one, anyone here vented the factory catch can to atmosphere rather than back to intake?

[Benny]

I think it is illegal to vent it to the atmosphere, hence why it goes back to the intake.

I doubt it will make much difference to power or tuning if it is vented to the atmosphere.
Why not pull the tube out and find out if it makes any difference and report back.

[bruce]

Illegal (affects emissions). Don't see any performance benefit. But if ya wanna add a blingy alloy catch can - go nuts.

[PASHN8]

I know it isn't legal, neither are pod filters, boost controllers, variable sound exhaust systems, certain coilovers etc etc, I was asking purely from a mechanical perspective

It would seem that from all reports even having the factory catch can, there are still oily vapours released back into the intake which in turn coats the intercooler/pipes etc with a film of oil in the piping.
I have vented my catch can air return to atmosphere through a small discrete breather and blocked the factory return, was just wondering if anyone had done the same?

Bruce do you have an SE/SP? Bling catch can? No thanks!

[Boyracer]

I had the SE race car venting to a tank...it was filling with oil...ended up blocking off the big hose that goes down to the sump...it was sucking up oil from their....

[PASHN8]

Thanks for that pic Boris, very interesting!

I'm not sure I agree with the need to fit a second can in series, because if you observe the factory design it seems quite good, the only deficiency in there will inevitably be 'some' oil coming back into the intake.

Below is how I have currently plumbed my setup, K&N breater mounted on the vertical factory catch can air OUTLET venting to atmosphere and factory return line that goes back to the inlet is not properly blocked.



Seems to be working well so far with clean charge pipes?

[PASHN8]

hehe

Actually, believe it or not that is how you plumb a catch can in to a car that doesn't already have one, so i'm not sure about what you mean when you say cutting off vaccuum to the crankcase?

[BitRusty]

PASHN8, do you have any pics of your breather setup? i'm looking for options for my SE

cheers

[PASHN8]

Ok, have snapped some pics and will post them up tomorrow.

[PASHN8]

Apologies for the delay!









Seems to be working well, as the intake pipes are now clean as a whistle and extremely subtle to the untrained eye!

[BitRusty]

Ahh thanks for the great pics

[PASHN8]

Correct, the turbo inlet is now sealed.

The whole purpose of this exercise was the ensure no crankcase gases return to the inlet, catch can or not. Catch cans do separate a large amount of the oil vapour from the air, but I can assure you a noticeable amount still returns to the intake.

If you don't believe me, try blocking the air inlet return and vent to atmosphere and check the levels of oily residue in your pipes, quite noticeable

[PASHN8]

Hehe, I actually thought you were disagreeing with me! lol..

I agree with you also, your solution does work definitely, I just didn't want to add another apparatus to my engine bay and used to use this method on my old Lancer Evo III and SR20DET 180sx, hence it was natural for me to solve it this way

Do you plan to fit the 02 Clamp?

[PASHN8]

TRB, IIRC the 02 clamp actually removes/improves the lean tip in/'lag' feeling under 5k under WOT and after fitting it can confirm this.

Without it's final adjustment, the 02 clamp has unbelievable results for the money! Car is sooooooo much smoother now under WOT with the hesitate under 5k almost non-existent, i'm a very happy camper now

Car is going on the dyno tomorrow morning for some adjustments and power run, I will also use this opportunity to set the 02 clamp trigger as accurately as I can using the load from the dyno to simulate road conditions.

I have also purchased the resistors needed to defeat the factory boost cut, but will not fit it until we see what sort of A/F's we are getting. I'll be happy with a steady 10psi across the board until I make the decision whether to fork out for a set of 440's and a Haltech intercepter.

The tuner who is setting her up is one of the most well-known and highly respected Nissan GT-R tuners in Australia, so I have full-confidence the the outcome will be satisfactory, but most importantly, safe for the longevity of the motor and running gear. Will post results tomorrow.

[Fuzzlet]

Curious - what is the boost cut level at? From memory it was around the 10psi mark