Can anyone explain this mod causing MASSIVE overboost on a stage 1 remapped car with decat?

With the J tube in place, I spikes at a normal 24-25psi and then holds at 23 dropping to 22.

However with a 19mm bit of "elephant tube" to the rear of the car, if I floor the pedal at about 2.5k in 3rd gear it spikes at 26psi, holds momentarily at 25 then 23-24psi.

It even spiked at 27-28psi on a couple of occasions!"

Think I might put the tube back on...lol

Can anyone explain this mod causing MASSIVE overboost on a stage 1 remapped car with decat?

With the J tube in place, I spikes at a normal 24-25psi and then holds at 23 dropping to 22.

However with a 19mm bit of "elephant tube" to the rear of the car, if I floor the pedal at about 2.5k in 3rd gear it spikes at 26psi, holds momentarily at 25 then 23-24psi.

It even spiked at 27-28psi on a couple of occasions!"

Think I might put the tube back on...lol

You did completely bung up the hole in the air intake when you took the pipe off didn't you?

Yep, air tight 24mm rubber chair leg grommit over it

Weird...

I'm going for a bit of added red engine bling! Would this hose do the job?

1/4" I.D. x 1m Red Multi-purpose Oil/Air/Water Hose

Hose World Ltd Multi-purpose Oil Hose (Red)

Thanks guys. John

It's 1/4" the right size for coming straight out the CCV and running it under the car to the atmosphere?

No 3/4"

Cheers, but at £6.50 to post some hose, I don't think so!!

Read this about an hour ago and now have my own Hose Nose fitted. Half a washing machine waste pipe and a rubber chair leg end form BnQ and job done. The small end of the hose fitted straight on nice and snug.

..and what a difference! It is sooo much smoother now, weird, can't stop grinning:D

All for less than a tenner and 5 mins of work. Smokes a fair bit but have run it behind the front axle to keep it away from the air intake for the heating etc.

My intercooler must be full of crap judging by the smoke coming out of the hose.

Moochos thanx for the idea chaps!

Just a reminder for anyone who has put a filter/wire wool in the catch can.....give it a check it may need cleaning out.....I dont mean the water collected.....u get a combination of oil and water emulsion....a bit like when a breather clogs up. Just a heads up as mine was disgusting....lol,. And I made sure when I did mine a year ago my catch can and pipe were all big bore to make it free flowing.

Before I ran it to air, you know that bend at the bottom of the intercooler? When I looked up at it in the gap under the car before it was always dripping with oil

Now, no dripping oil coming from it at all

I've noticed my atmospheric pipe has got rid of heaps of oil as the end of the pipe is covered in it and is always steaming :S

Still oil at the aforementioned intercooler pipe but didn't look before doing this mod so can't compare.

I'm thinking of doing this mod so I've been reading all of the available material on the subject.

I would like to vent to atmosphere to stop any warm air going in to the intake and I would run without a catch can. I've read of peoples concerns about the negative pressure in the crank case when the engine cools down causing a vacuum and sucking in to the crankcase.

This got me thinking, what if I were to put a one way valve on the end of the 'elephant hose'? Then the vapour can escape when the engine is running, but when the engine is off and cooling no air can get back up the hose.

Can anybody see any issues with this?

after reading this whole thread got to say some have went way overboard....as basil says the simple way is the way to go...block air intake ...run the crankcase pipe to bottom of engine to atmosphere.

how can it make any diff to the running of the car? the pipe goes to the unpressurised turbo intake so any air lost is taken from the filter side and pressurised by the turbo to the psi the turbo runs at anyway. the gains you get is losing the oil vapoured air being sucked through the turbo and all the way through the intercooler and pipework and eventually past the egr and mixing with the spent exhaust gases the egr utilises and clogging things up a bit..so to erradcate all this vent the crankcase to atmosphere under engine and remove the egr vacuum pipe and block the pipe.

some of the jobs done do look nice but just arnt necessary. :no:

Edited 24 May, 201016 yr by warwick hunt

Hi I am interested in doing this mod but have a few questions:

Does this not stave the Crankcase of of air and as you are effectively blocking up the intake?

How does it then dispel the unwanted fluids (oil etc) out of the same hose that was connected to the intake? :S

Does the original system take in air through the same pipe as it throws the crap out of then? :S

Hmm after having a little read around I gather that the air drawn in for the crankshaft ventilation system is not being drawn in from the pipe coming of the intake but somewhere else?

That pipe is just where the "crankshaft crap" is being dispelled to? So it can be recirculated and re-burnt by the combustion system etc.

And that all you are doing with this mod is taking that crap and putting it else where? Thus saving that crap from going into your intake/intercooler and raising induction temps etc

Edited 29 May, 201016 yr by Thirdtimeluck

:yes:

:yes:

I do have one other pondering query however; How is the "unwanted vapour" extracted from the crank case with this mod? The OEM set-up has the air intake sucking it out and spitting it back through, but with this mod it is no longer being actively sucked out (as you block off its route to the air intake system). How can one be sure its all still get removed with this mod?

I do have one other pondering query however; How is the "unwanted vapour" extracted from the crank case with this mod? The OEM set-up has the air intake sucking it out and spitting it back through, but with this mod it is no longer being actively sucked out (as you block off its route to the air intake system). How can one be sure its all still get removed with this mod?

The crankcase runs under positive pressure.

The crankcase runs under positive pressure.

hmm okie but its still not being "sucked" out like before. Surely it cant be as effecitve? :S

hmm okie but its still not being "sucked" out like before. Surely it cant be as effecitve? :S

Put your head near my wheel arch - you will soon see just how much crap comes out the end! It doesn't need to be 'sucked' out - the positive pressure in the crankcase alone really shifts all the unwanted stuff

imagine a kettle...how does the steam get released..

of course...through the open ended spout... :yes:

imagine a kettle...how does the steam get released..

of course...through the open ended spout... :yes:

ah ok but the kettle's spout is at the top of it as hot air/vapor rises. :yes:

But the "elephant pipe" goes from the CCV downwards towards the ground (if no catch can) :S

Edited 9 June, 201016 yr by Thirdtimeluck

There is no vacuum in a diesel intake manifold, so in no way does any of the PCV gases get 'sucked' into the manifold. Diesels generate a load of positive crankcase pressure, so the PCV gets forced out by crankcase pressure and nout else.

Has anyone got a link to a gromet type plug, to plug up the intake pipe?

Also is the hose diameter 20mm

Stephen

Has anyone got a link to a gromet type plug, to plug up the intake pipe?

Also is the hose diameter 20mm

Stephen

theres a 1000 things to plug the pipe with...i used an old indicator bulb :yes:

and yes pipe is 20mm..

ah ok but the kettle's spout is at the top of it as hot air/vapor rises. :yes:

But the "elephant pipe" goes from the CCV downwards towards the ground (if no catch can) :S

There is no vacuum in a diesel intake manifold, so in no way does any of the PCV gases get 'sucked' into the manifold. Diesels generate a load of positive crankcase pressure, so the PCV gets forced out by crankcase pressure and nout else.

:yes: