Intake Plenum? intake mods? worth it for 996 3.4 C4

[STEVEG]

There are lots of induction tuning mods listed for 996, being very new to Porsche am wondering what your comments are relating to induction mods..
1/ IDP's Plenum intakes are quoting a massive 23hp and 21 torque at wheels on a dyno for this simple bolt on?
2/ K&N Filter replace stock filter?
3/ K&N Air Induction Kit?
4/ Will be giving the car an oil change soon,
http://www.design911.co.uk have a billet aluminum hard-anodized magnetic drain plug for £19.95 better than stock?

[RichardKS]

There's been a fair bit on this stuff in the last few issues of Total911 (yeah, I know it's rubbish...) but one of their 'living the dream' or 'living the legend' (or whatever it's called at the back of the mag) writers - Joel Newman - has an early C4 with mods. Might be worth picking up some back issues?

[jmgarage]

My recommendation for finding power in a 3.4 or 3.6 engine is actually a replacement exhaust (manifolds all the way back) enlarged throttle body, induction kit and a custom remap to get the benefit from the modifications.

Of all of that, the exhaust and remap are the best sources for extra power.

Problem with the intakes, they rob peter to pay paul so to speak... they give a peak increase at the expense of torque (lower rpm power) or power from under the graph all across the range, which is the problem with most power mods which have been developed to produce a peak figure for advertising these days.

I would not look for a peak figure increase, but look for something that improves the graph for as much of the area as possible in torque or bhp, as this will make the car faster, period... So you might only make 5 or 10 bhp with a good mod, but that will be spread over the whole graph, improving the 0-60 time significantly, whereas 20bhp peak, which only happens in a 500 rpm range, and removes 5 bhp from across the range will make your car slower than standard.

[Paul Mabley]

My recommendation for finding power in a 3.4 or 3.6 engine is actually a replacement exhaust (manifolds all the way back) enlarged throttle body, induction kit and a custom remap to get the benefit from the modifications.

Of all of that, the exhaust and remap are the best sources for extra power.

Problem with the intakes, they rob peter to pay paul so to speak... they give a peak increase at the expense of torque (lower rpm power) or power from under the graph all across the range, which is the problem with most power mods which have been developed to produce a peak figure for advertising these days.

I would not look for a peak figure increase, but look for something that improves the graph for as much of the area as possible in torque or bhp, as this will make the car faster, period... So you might only make 5 or 10 bhp with a good mod, but that will be spread over the whole graph, improving the 0-60 time significantly, whereas 20bhp peak, which only happens in a 500 rpm range, and removes 5 bhp from across the range will make your car slower than standard.

I agree with this man!

In addition, induction kits taking [very] warm air from the engine compartment in a 996 defeat the object in my opinion.

With these engines there's not a lot to be gained, certainly not worth the money. Leave it as it is unless you're willing to spend megabucks in which case you could just buy a GT3.

[Brett928S2]

Hi

Nitrous... 100 hp for around £1200 (including a controller) ....

All the best Brett

[STEVEG]

Thanks for the info guys, plenum is lot of money, only performance info I could find is from the guys that make them, I am not going there, will go for tuned exhaust system when mine fails off.

As for cold air intakes( advertised) many of them....

I agree with you it will be drawing hot air from engine however which way it's designed, only thing that might be used to get cold air, is mounting a land rover snorkel..:~)).or running a plastic tube from the interior passenger vent duct to the air filter box and switching the air con on??)))

[jmgarage]

Your engine draws more air than than your air con could keep up with, besides, thermodynamics would dictate that the energy consumed by the engine to run the air con compressor, would consume more power than would be gained by the reduction of intake air temperatures.

Whenever you convert energy from one state to another, you can never gain more energy out than has been put in, often converting energy from one form to another actually consumes a large percentage of the source energy, with just a small amount remaining in the second form.

Which is why electric cars, that you plug into a socket to charge, that is in turn fed by a national grid system, which in turn also looses energy, in turn fed from a coal or oil powered power station, is a complete oxymoron when referred to as green energy... Power stations do not have catalytic converters, much of the energy is lost in conversion and transportation, when it would be better for the environment to have a coal or oil powered car, and less of the fuel would be consumed in the same journeys.

Anyway, off the topic a bit....

So, if you have a source of cool air, it is better to duct that to the intake.

Sometimes in efficiency studies you can find a double wammy, such as a turbo, which turns wasted energy into partially recovered energy, or if you found a way of taking air, which otherwise would be an obstruction to the progress of your car, and use that for the cold air feed.

Many years ago I knew a chap who made racing motorcycles in the cafe racing days, he used to pass the engine oil into the frame of the motorcycle, so it acted as an oil tank (so saving weight) and acted as a large surface area oil cooler (also saving weight) all in one.. that is a good example of a double wammy.

Likewise, with a 996, you could in theory, duct air from your front bumper (restriction to the car moving through the air, partially reduced), which would be pressurized at speed (increasing your air intake slightly, a little like a turbo (just very small), duct it to your sills (airflow through the sills on a regular basis could actually keep them dry and so less likely to rust in time (although when driving through the rain it may be a different story) and then duct that to your air box (achieving the original goal)..

... but then again, that is a lot of work for a little gain, which, as funny how it goes, is exactly how often the way thermodynamics works as well..

(and before anyone else says it, of course energy is never really consumed, it just ends up in another form, when I say consumed, I mean that it has been converted into a format other than the desired format)

[STEVEG]

Thanks for the info Jon, very informative... BTW the landrover mod and air con mod was not a serious issue, my failed attempt at a bit of light hearted humour..
cheers...

[jmgarage]

Nooo I got the joke, I was going to suggest adding a leaf blower

But you would not believe how many times customers and people on forums have asked if it would work, and in which cases I explain the above info, which in particular was included for anyone that read it and was going to ask if or how it would work. A bit of preemptive work there from me.

[STEVEG]

lol... leaf blower now that's what I call a mod!

[jmgarage]

People playing around with leaf blowers on a dyno!

[PaulSmith]

Now we just need to rig up some seats on the bonnet so Mark and Jamie have somewhere to sit for open road tuning with NOS and Leaf Blower

[jmgarage]

We could mount some seats on the bonnet, but then again, with current unemployment rates, it may just be doable to mount an unemployed person on the bonnet, put some ducting from a respirator to the intake, because at speed I suspect a screaming human will provide just as much airflow as a leaf blower!

What I find interesting though is that a 3 or 4 horse power motor on a leaf blower, with maybe just something like a 20cc engine, can produce airflow which will improve the power of a 160 BHP engine by 10 BHP .. Which again is an interesting study for thermodynamics as an example of energy (fuel) being converted into torque, which in turn is being converted into airflow, which is then converted back into torque via combustion... Which should not work, unless, there is an inherent flaw in the car engine which the leaf blower is attached to, either a restrictive intake, or a fueling problem which is being corrected by the additional airflow... But anyway, a good example of thermodynamics, how the rules hold fast and if something seems to be cheating thermodynamics, there is probably something else at play.

Then again, I could be wrong, and the leaf blower may have a 20hp motor... But as a good example, I think that on UK single phase plug, 3kw or 4hp is the maximum motor energy you can use before you blow a fuse, so that would be the maximum power of an electric leaf blower and a 20hp petrol one would be massive!