Induction enhancment

[Cheddar Bob]

So back in my boy racer days induction kits were all the rage, although saying that, they were very handy in my more motorsport oriented vehicles. Has anyone considered adding a scoop to the inlet side of the car to force more air into the pod?

It may not look the most pretty but, I can't seem to find anything where this has been done previously, which tells me it isn't worth doing. I am surprised that an induction kit isn't available to house the filter in the pod itself, so further from the source of heat. 

What do you think? 

[golfprorich]

The induction side of the 986 can be improved by the 987 airbox which is slightly larger. But as far as getting air to it other than cutting a big hole in NSR wing I think what Porsche have done is best - anything else would offer little or no benefit. If you want a little more noise then de-snorkel it  

[edc]

Further from the source of heat?

The air intake is from outside the wing anyway. It routes round the premier of the engine bay then up centrally to the throttle body. Moving the air entry point a couple of inches further out won't affect the rest of the routing where the charge is being heated. 

[Berni29]

Hi

When I read up on this sort of thing recently it seems that the speed you need to be going to make the "ram air" effect worthwhile is too high for a road car. Certainly well above the legal limit.

Berni

[Cheddar Bob]

2 hours ago, Berni29 said:

Hi

When I read up on this sort of thing recently it seems that the speed you need to be going to make the "ram air" effect worthwhile is too high for a road car. Certainly well above the legal limit.

Berni

Thanks berni. I was aiming along that route. I was aware ram it is a real solution but overlooked the speed factor. 

@edc good point, the inlet temp should be lower if the air is cooler at the front, but the proximity won't change as you get closer to the inlet manifold. 

@golfprorich I've already took off the snorkel. 👍 That's what gave me the idea of increasing the air into the chamber. 

 

[Lennym1984]

I'm sure that somebody on here did move the air filter (a cone style aftermarket jobbie) itself into the wing area. I think that their feedback was that it was just too noisy and didn't appear to offer any peformance benefits.

[Araf]

Probably an easier way to get more oxygen in would be to cool the induction temps.  Maybe a matrix in the path of the air, tapped off the air con, would give that crisp morning effect when the ambient temperature is up?

[½cwt]

I have seen a picture of a scoop fitted to the induction inlet, but I'm uncertain of the effect as trying to get too much air into a system can cause stall and back pressures that are counter productive.  Porsche will have spent quite a lot of time designing how to get the best quality of air into the induction system.  The main aim for a naturally aspirated engine is to get a controlled stream of the coolest possible air, but not turbulent/stalled air, to flow through the induction system.  If you look at the two inlets on the rear wings of the 986 you'll not there is more of a lip on the leading edge of the left side which along with the engine sucking in air 'trips' the air flow alongside the car, the coolest/cleanest available, into the inlet duct.  The air box then acts as a plenum for this air to be drawn into the engine through the throttle body by the action of the pistons. This 'suck' on the volume of air in this plenum allows the pipework and the head ports to induce the swirl effect into the system so the injected fuel mixes as completely as possible to get the the most efficient and complete combustion.  If you get too much positive pressure the suck effect is neutralised and the airflow could be disturbed from the pattern Porsche designed.

With a duct if you think about it if you are doing 40mph and ask for full throttle at 3000rpm then its fine, that's fine but at say 120mph on track even at max revs in you could well be ramming in more air than the engine can efficiently consume even at full throttle and that's when you get back pressure messing things up unless you redesign the whole inlet tract system to suit the pressure profiles achieved by the effect of the duct.  

If you want more noise (and a small loss in induction efficiency), desnorkel.  If you want more air, keep the inlet as is but go for the 74mm throttle body and air box upgrade along with a re-map.  Or buy a 911 turbo!

[edc]

The best value mod to get air in to make a bit more power is 74mm throttle body and £35 996 plenum. 2 X 90 degrees silicone bends and a 1 foot alu pipe. That will be less than £200 and better than an induction kit. Add the 987 airbox for more again but it is more involved to fit. Lots of previous threads on this. 

[Ninesomething]

It might be just as effective to wrap all of the inlet pipe in that asbestos wrap that people put round headers. It works to keep heat in headers it will also work to keep the engine heat away from the incoming air. Performance gains? Probably unnoticeable. No extra noise either. 

Probably best if I shut up.

[Cheddar Bob]

36 minutes ago, JonSta said:

It might be just as effective to wrap all of the inlet pipe in that asbestos wrap that people put round headers. It works to keep heat in headers it will also work to keep the engine heat away from the incoming air. Performance gains? Probably unnoticeable. No extra noise either. 

Probably best if I shut up.

That's mega

[Cheddar Bob]

Thanks all for your input. @½cwti can't disagree with your porsche comment. I just like to tinker 😎

Not really sure what I'm after. If I want more power it will be cheaper to buy an S

More noise remove the cats

 

[Boxsum]

56 minutes ago, Cheddar Bob said:

Thanks all for your input. @½cwti can't disagree with your porsche comment. I just like to tinker 😎

Not really sure what I'm after. If I want more power it will be cheaper to buy an S

More noise remove the cats

 

I’ve read that the manifolds are quite restrictive so changing them and the air filter are cost effective mods. That’s what I’ve done and quite pleased 

[½cwt]

35 minutes ago, Boxsum said:

I’ve read that the manifolds are quite restrictive so changing them and the air filter are cost effective mods. That’s what I’ve done and quite pleased 

Probably true, but then again you couldn't have a Boxster being quicker than a 911 could you?  New manifolds would be a massive amount of rework and would need a lot of R&D too.

 

1 hour ago, Cheddar Bob said:

Thanks all for your input. @½cwti can't disagree with your porsche comment. I just like to tinker 😎

Not really sure what I'm after. If I want more power it will be cheaper to buy an S

More noise remove the cats

 

That's why I went for an S, no wishing for more power and wondering what the  the bigger capacity car goes like 😉.

For real noise change all the induction to trumpets and throttle slides to look something like this from a V6 Honda powered Ralt RH6 F2 car:

 

Now that would give you hard core induction roar (and even worth a transparent engine cover), but same or even bigger R&D problem!  No cats would certainly amplify the exhaust too.

[edc]

The £100 ish manifolds of eBay work fine. Been on my 2 986 since 2012 and show before and after Dyno gains. 

[Cheddar Bob]

7 hours ago, ½cwt said:

Probably true, but then again you couldn't have a Boxster being quicker than a 911 could you?  New manifolds would be a massive amount of rework and would need a lot of R&D too.

 

That's why I went for an S, no wishing for more power and wondering what the  the bigger capacity car goes like 😉.

 

I'm not unsatisfied with the 2.7. I just like to fiddle. I'd be the same in your car

[½cwt]

8 hours ago, edc said:

The £100 ish manifolds of eBay work fine. Been on my 2 986 since 2012 and show before and after Dyno gains. 

Exhaust, not induction I assume?

[½cwt]

2 hours ago, Cheddar Bob said:

I'm not unsatisfied with the 2.7. I just like to fiddle. I'd be the same in your car

Absolutely.  I'm not sure what would be too much to make it easily useable but I'd fancy a run in a 300 bhp 986 Boxster just to see what the difference is.

[Cheddar Bob]

55 minutes ago, ½cwt said:

Absolutely.  I'm not sure what would be too much to make it easily useable but I'd fancy a run in a 300 bhp 986 Boxster just to see what the difference is.

There is a strong argument for keeping the power to a happy medium. That said throttle control kicks in when there's too much. In theory a more powerful car in the same chassis should be faster with careful throttle management 

[edc]

On 9/2/2020 at 8:20 AM, ½cwt said:

Absolutely.  I'm not sure what would be too much to make it easily useable but I'd fancy a run in a 300 bhp 986 Boxster just to see what the difference is.

Drop in a 996 3.4 and job done.

[edc]

On 9/2/2020 at 8:19 AM, ½cwt said:

Exhaust, not induction I assume?

Indeed. It was in reply to another post. 

You can spend a lot of money on mods on a relatively cheap 986. The sweet spot for me is a mixture of off the shelf parts like the 996 throttle body and plenum and the cheaper exhaust manifolds. You can spend 2 or 3 or more times as much for the same type of product but achieve little or nothing on terms of extra power. 

[Cheddar Bob]

The irony is learning to drive the car will outweigh any amount of power increase

[edc]

Of course some mild mods won't make you a pole contender overnight but for many the car, experience and ownership experience is part of the fun and whole experience. Some enjoy being the 'best driver' but other equally enjoy the process and outcome of modding itself. The extra power or speed is an outcome of that not necessarily the sole objective. 

[Lennym1984]

1 hour ago, Cheddar Bob said:

The irony is learning to drive the car will outweigh any amount of power increase

Very true and part of the reason that I find the "the 2.5 is too slow, you must buy an S" brigade so laughable.

When I first started taking my 2.5 on track it was very slow. It used to understeer through every corner, brake too early, get on the power too late etc. I'm reasonably certain that I had the slowest car out there on my first time (versus clios, MX5s etc). Amazingly after doing plenty more track days and taking a few hours of tuition, my car suddenly started performing a lot better. It could brake late into the corners and carry enough speed to get past faster cars on the straights. Despite being a lowly 2.5 with an asthmatic engine and terrible brakes (you have to have the S brakes because they're "the best ones") I could easily outlap cars with significantly more power. The limiting factor for me now is bravery (and skill) rather than car performance.

It's why I now prefer the base model Porsches (I have a 2.7 Cayman now). They force you to adopt good habits in order to get the best out of them.

ETA: I also totally agree with EDC above. I love tinkering with cars and the journey of modding them is definitely an enjoyable factor regardless of whether or not you go near a track.

So in conclusion, everybody is right apart from the people who never go above 5k RPM and then claim that the 2.5 is too slow

[Cheddar Bob]

5 hours ago, Lennym1984 said:

Very true and part of the reason that I find the "the 2.5 is too slow, you must buy an S" brigade so laughable.

When I first started taking my 2.5 on track it was very slow. It used to understeer through every corner, brake too early, get on the power too late etc. I'm reasonably certain that I had the slowest car out there on my first time (versus clios, MX5s etc). Amazingly after doing plenty more track days and taking a few hours of tuition, my car suddenly started performing a lot better. It could brake late into the corners and carry enough speed to get past faster cars on the straights. Despite being a lowly 2.5 with an asthmatic engine and terrible brakes (you have to have the S brakes because they're "the best ones") I could easily outlap cars with significantly more power. The limiting factor for me now is bravery (and skill) rather than car performance.

It's why I now prefer the base model Porsches (I have a 2.7 Cayman now). They force you to adopt good habits in order to get the best out of them.

ETA: I also totally agree with EDC above. I love tinkering with cars and the journey of modding them is definitely an enjoyable factor regardless of whether or not you go near a track.

So in conclusion, everybody is right apart from the people who never go above 5k RPM and then claim that the 2.5 is too slow

I thought the car went bang at 5100rpm... Does it not 😂