Thread: 2.2 TDCi (Puma) CAT Delete

Originally Posted by martnH

So which one is better?
Decat vs. cold air intake

It is well documented that a snorkel will rob engine performance

I was thinking of getting a three way valve...You know with a lever.
Going off-road, air via snorkel
Going highway, air via cold air intake.

Cat stay alive!

Cheers

That's interesting. I have heard it argued that a snorkel improves cold air intake. No idea if that's true or not.

What I did is to shorten the snorkel and I find this resulted in noticeable power gain , turbo spools up faster and lower egt.

In other words, when I first installed the snorkel, the snorkel rob the engine a few horsepower and now by partially remove the snorkel and improve the ease of air going into the motor, I regain that lost performance.

So i throw out the argument that maybe the removal of long snorkel can achiece better engine performance gain compared to killing the cat, given that puma is a big cat afterall.

Killing cat will upset the puma


Jokes aside, Peter at BAS have done some experiments with dyno graphs showing a snorkel will reduce horsepower. So what I have done here is really the best of both worlds, when off-road I connect the snorkel for engine protection, while on-road, I remove the snorkel for better engine performance

Those snorkels are the worst for flow out of all snorkels on the Defenders.
The BAS power tests were done tuned.

Did you test connected and disconnected at full operating temperature in the same area during the same weather conditions?

And you still haven’t solved the Issues the Cat removal is done for....
Cooler floor, cooler handbrake and quicker spool...

Originally Posted by martnH

So what I have done here is really the best of both worlds, when off-road I connect the snorkel for engine protection, while on-road, I remove the snorkel for better engine performance

True but you could do better. If you can, go out of the wing top opening and put the factory grill back on the side opening to let air flow out of the engine bay. Then when wading, run a hose from wing top outlet to snorkel extension.

Snorkels that mount to the side intake do restrict air flow, even the factory attachment that fits to the side vent is a bit rubbish. That said only worth looking at if your tuning up.

Pic attached gives you the idea

Any intake can be ‘tuned’ by lengthening or shortening the induction path but there are always limits. Pro’s include cool (denser) air, the ‘tuning effect’, the ‘ram’ effect and relatively reduced dust but cons are the potentially reduced airflow due to static air and back pressure within a long, thin snorkel. This will vary greatly depending upon the individual engine. Unfortunately the designed length may not suit all of these attributes so without some kind of objective testing you will never know.

Originally Posted by Tombie

Those snorkels are the worst for flow out of all snorkels on the Defenders.
The BAS power tests were done tuned.

Did you test connected and disconnected at full operating temperature in the same area during the same weather conditions?

And you still haven’t solved the Issues the Cat removal is done for....
Cooler floor, cooler handbrake and quicker spool...

I have quicker spool too by removing the snorkel tube

With regards to the hot floor and hot handbrake...
I will argue these are very similar to health raditiaon physiotherapy.

The heat transmitted via the handbrake will increase blood circulation of driver, particularly the lower limbs which promotes healing and relaxing of muscles.This is very beneficial for long distance driving. (Thanks caveat is you will need to hydrate and if you have varicose veins, heat will worsen this condition

Also quote"
-Heat can improve the flexibility of tendons and ligaments
-Heat will reduce muscle spasms
-Heat may alleviate pain (heat may induce the release of endorphins, powerful opiate-like chemicals which block pain transmission.)
Heat will elevate blood flow (heat tends to relax the walls of blood vessels)
Heat will boost metabolism.Heat can help when stretching muscles and increasing overall flexibility."

I can't edit...I meant to say
Heat physiotherapy

getting a bit off topic here, but i believe JLRs narrow hodge-podge intake ducting would render any "ram-air" type effect pretty redundant. At best, removing a snorkel is surely just going back to factory-spec, so not really a "gain" by definition