Induction Kit Theory/Enquiry??

JDMaaad

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Location
New Zealand
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Volkswagen Golf
According to TorqueCars, "Do induction kits always add power? NO - typically power gains are toward the top end of the RPM range and some engines will show a power loss, especially low down."

but they also say "So the best air induction kits come with a cold air feed pipe and are fitted in an air box"

So are they basically saying that JUST AN air induction kit won't give power but AN air induction kit with cold are feed pipe fitted in an air box delivers power?
Thanks in Advance :)
 
It depends on the design of your induction kit. A CAI or a SRI will have a big fat induction pipe to feed unrestricted air to the turbo.

There's a cold air intake that draws in air from a source separate from the hot engine air that stays cool and doesn't have issues with increased IAT. The piping is smooth, high flow and it has no sharp angles. A CAI will net you some power gains, but usually not peak power, but it will change your power curve and give you more average power.

A short ram intake draws air from the engine bay which is hot. It has a short run to the turbo, smooth piping and has very high flow. If properly made with an air dam and air fed from a cool source it can have the same power gains as a CAI but only while the car is moving and air is forced into the area it draws air from.

I have seen dyno runs of well made induction kits and the power gains are in average power not peak (it will raise your power band) and are in the middle of the power band. But this is not the same for all cars and it takes quite a lot of planning and engineering to make it right. For my Genesis Coupe I have an Injen SRI. It has an air dam, air is fed from 2 sources in front, I have heat wrapped the tubing right down to the silicone flex pipe at the turbo. My IAT is similar to what it was when I had the stock air box, even lower when I am up over about 40 MPH. In stop and go traffic it sucks hot air and IAT go up.

I watch my IAT using the Torque app. At arounf 40 MPH my IAT are 9-12° C above ambient. At highway speed (70+ MPH) they are about 6 over. Every ~6° C over ambient you go, you lose 1% of engine output. It's all about keeping those IAT down.
 
If you're looking for an induction kit you need to remember that you are not guaranteed extra power on many engines. Some engines will give a little more power if the standard intake is restrictive by fitting an induction kit.

BUT the most important thing is that you need a cold air feed to the induction kit or you will definately not see the gains you were hoping for. Warm air just saps power! So both conditions need to be true to have a chance of seeing a power gain.
 
Factory air boxes are better than most people seem to think. The amount of induction kits I've seen fitted which have at best, added no power, and in many cases reduced power (dyno tested) is unreal... The same goes for exhausts. Milltek claim power gains on their systems, but the Milltek for my RS4 sapped power, and the Milltek a friend of mine fitted to an R8 at his workshop also sapped power on the dyno... Go figure!
 
I felt a bit of a drop in my E55 AMG swapping to a twin cone set up, also no extra noise which was disappointing! then changed for some K&N panel filters and these killed the MAF within a couple weeks :(

Fitted new standard MANN filters, new MAF and was back to how it should be :)

I've always swapped the standard intake though, mainly for the noise! On one car I just jubilee clipped the filter onto the end in the wing instead of the air box, no issues. The last two have had to stay in the engine bay because there's no room for additional pipework, but had a heat shield supplied with them (BSR) happy with both set ups there :)
 
The prob with the car manufacturers is that they aren't considering pure performance. They have laws to obey, in the US they have CAFE standards, noise reduction and all kinds of other crap that suck for performance. That's why we all tne- to make the car EXACTLY what we want. Some want noisy, some want quiet, we all want more power.

I wrote this for another forum and I'll copy and paste it here.

I have wrapped things in my 13 2.0T engine to try and protect the intake/IC piping from heat but I haven't touched anything that may mess up my warranty in any way. I figure wrapping a pipe is safe. My IAT has come down a lot since I started this thermal management. Sure, I'd love to do a phenolic spacer, bigger IC etc but I want to preserve the warranty.

There's 2 types of heat wraps I have found for my car. Exhaust wrap which is thick woven glass fiber in a roll that you get at auto parts stores. It's pretty expensive and is held on with metal banding. There's also metallic heat-reflective tape with a thin woven glass backing that sticks on. It also costs a lot for what you get.

-Exhaust wrap is good at keeping heat in and insulating piping. It's a good barrier against convective heat.

-reflective tape is good at keeping radiant heat out, but not insulating. Don't wrap hot stuff in reflective tape as it will only help the hot things radiate heat.

I have my Injen SRI piping wrapped in exhaust wrap and covered in refective tape to protect it from the flaming snail next door. That piping was getting hot to the touch before I wrapped it because of radiant heat AND convective heat in that area. Wrapping it brought my IAT down by about 50%. I measure my IAT over ambient after a 30 min run on the highway. In stop and go traffic it changes so much it's hard to get a definite number. Then I wrapped the post-IC upper part of the piping and the TB with the reflective tape. That piping runs right next to a big hot coolant line that radiates heat. That brought my IAT down about 2C. Just by wrapping (I did some trial and error and ended up wasting a $22 roll of reflective tape) I brought by IAT down quite a bit. With the drilled out hood vents and wrap, my warranty is unaffected and after that 30 min run on the highway my IAT stays steady at 5-6C over ambient. After 2 miles from leaving my house with a cold engine I hit that 5C over ambient and it stays there on the hgihway as long as I keep moving.

What else can be wrapped? What about fuel lines? Cooler fuel is also denser just like air and carries more energy- but will it make any difference in that part of the engine bay?

You don't want to use reflective sleeving on hot piping. It just turns the piping into a radiating heat source unless you have insulated the pipe underneath.

I originally wrapped the hot side IC piping with reflective tape and it INCREASED my IAT. It turned the black silicone into a radiator as the reflective material radiated out the heat from beneath. Use refelctive material on the cold stuff or wrap it with insulating material first.

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I'm not sure of the brand that I used. I got it at Advance Auto. The reflective tape is silver, comes on a small roll. the exhaust wrap is right next to it in the same aisle (the exhaust wrap is under the reflective tape on the SRI. The difference in heat soak is dramatic, the SRI aluminum tube only feels warm to the touch, before it was too hot to hold your hand on for more than a few seconds)

It's a novel. grab some hot cocoa, a blanket and cuddle up with your computer next to a fire if you want to read it all!
 
There are really two seperate answers to this questions first for stock(ish cars) and then for tuned ones.
Stock
It depends completely how well the intake system has been designed. When cost is important some gains may be possible but on a well designed modern system changing just the box isnt likely to do anything other than make a different noise,

On tuned engines it is a completely different question.
Stock boxes often flow enough for stock power (and a bit more) but if you are tuning the engine a lot then the stock induction system probably will probably be restrictive.
Hardly surprising of course as it wasnt designed to provide air for a large hp gain.

The cold air question has a similar answer.
It should also be said that tubo engines usually benefit more than na engine but some of this is because they run much hotter under the bonnet.
 
Factory air boxes are better than most people seem to think!

I think this is especially true of cars like yours that are the top performance versions - their whole point is to get the maximum they can out of an engine - , RSes, BMW Ms, AMGs etc. What would be the point of the car maker putting a restrictive airbox on one of those?
 
their whole point is to get the maximum they can out of an engine

Not true. Their whole point is to get the maximum they can while sacrificing what they need to in order to keep noise down, adhere to emissions standards and keep company costs down. they don't mean to put on a restrictive airbox, but the compromises they HAVE to make (think emissions) and CHOOSE to make (think sound) are by there nature, restrictive.
 
please explain how an designing an induction system that deliberately restricts emissions is a viable thing on say a 500+ bhp super car because that is what I and yugguy are specifically referring to.
If you need to get better emissions you tune the engine a bit less less not tune if too much and then restrict it by poor induction.
That actually costs more and will causes more problems .

And to say that amg Ferrari etc don't mean to put restrictive systems on is just plain daft. Millions of pounds of research and they don't know what they are doing ? I think not.
 
Even high end manufacturers have to obey emissions laws. Any system can be made better, but with the higher end stuff you have to engineer the better replacement parts and that is not easy to do. But if YOU don't have to worry about emissions or noise, the gloves are off and you can do better. Race teams do this sort of thing with street supercars all the time and turn them into racing cars.
 
Which is why most cars benefit from a remap as this removes the restrictions and compromises forced on manufacturers my government, geography, variations in fuel quality, engine longevity, etc.
 
My car has fake hood "accents" (see my avatar) which are plastic and completely closed. In the stock form they do absolutely nothing except look cool. More and more manufacturers are doing this (at least in the US- the Mustang and a couple of Dodge muscle cars have fake hood scoops). I wanted to see what'd happen if I made the vents funtional.

I drilled out holes on the fake hood accents. There are probably 50 holes in the things now, but they are set up not as a scoop but as a vent. There's no forced air going into the vents. But they do vent out a little heat when drilled using the venturi effect with air running over the vents. My IAT went down by 1-2° C after a 45 min drive on the highway (I used my morning commute over the month I had the vents open to compare IAT with the accents undrilled before the mod). The big difference was when sitting in traffic, my IAT would stay down better because the vents would let some of the heat out the oven under the hood. But it wasn't enough of a change in temps to run with those ugly drilled out vents and since I have covered them with fake carbon fiber wrap. After the 45 min commute my IAT runs about 6-9° C over ambient.

My car also has a ram air scoop you can't see. It is on the front of the car and leads directly to the factory air box. When the factory air box was in my car, it was a closed system and worked well. I have an after market SRI now that uses the ram air scoop to feed cool air to the filter. I had a different (much cheaper) SRI before this one that didn't utilize the ram scoop and was not heat shielded. My IAT was a lot higher with that set up.

So yes, scoops and vents do work. If you set up a scoop though, you need to think about flow- where does the air go? Just letting in air won't do much, it has to exhaust somehow to move the heat out. I also have removed a lot of the rubber hood (bonnet) seals in the front and back of the engine compartment. This lets the air that comes in the front to flow through and exhaust over the windscreen out of the gap I created by removing the rubber seals.

I use a OBD2 port reader and the Torque app to watch IAT and I have done all this cooling tweaking using this setup only. I don't have under hood heat sensors or anything.

EDIT- sorry, I didn't even look at your car or username! If you drill out of dremel out and remove the hood vents it will reduce IAT. But with a NA car it's not as big of a deal. I have the 2.0T and heat is an issue with turbos.
 
It's usually a juvenile obsession that you grow out of :) Mind you I never grew into it, couldn't see the point of wasting my time and money making my car noisier. Making noise attracts attention, yes, but often the wrong sort. Also, most small road cars that are noisy are usually slow. Show me a car with an off the shelf induction kit and I will show you a slow car with, often, less power than standard.

Grow up, get a pair and do the job properly.

Me? A troll? Perish the thought :)
 
I see kits like that all the time where there was no thought given to heat or design. Unless you have a plan and a purpose you're not doing much good. It's part of an entire systemwide tuning to get the most from your engine IMHO but on its own doesn't do much for performance. That's a blanket statement however and each car is different.

That said, I have a juvenile obsession with that PSHHHH noise my BPV makes, the rattlesnake sound my wastegate makes and the various sucking and slurping noises (I'm getting kind of excited now) it makes too. Plus my kids love those noises and they are actually juveniles!

Once you go under an overpass bridge with the windows down you get it. My wife won't admit it, but she does smile when I show off like that :p
 
The problem, if it is a problem, is that the only people impressed are the impressionable young and those who have no idea about engine tuning. Those that do just think that you are a tw......:)

But if that is what you like and don't care what real car guys think, then go for it and enjoy.

For me, though, lb/ft wins over pointless noise every time. A powerful engine built properly will make the right noises without having to resort to tricks.
 
My induction kit on the ZS is fairly quiet compared to others, however it was made to optimise getting cool air into the engine which it does quite well. There is a science to obtaining the best induction design, not all cars can make the use of this due to space constraints and engine configuration. Back in the early 90s when I was working on such a design for a particular BTCC team the likes of Swindon race engines modified their heads by turning them through 180 degs so the inlet tracts were at the front rather than by the firewall, this aided airflow into the head and utilised the design concept and science involved. It didn't take long for the whole pitlane to make these changes once they saw the results of the first team to try it. 1st and 2nd in '93 GP support race.
 
[QUOTE="old-git, post: 283058, member: 2830

Grow up, get a pair and do the job properly.

Me? A troll? Perish the thought :)[/QUOTE]

:rofl::rofl::rofl:|B
 
If you just want the noise put a tape player under the bonnet.

However it should be pointed out that if you are running a turbo(s) on high boost then a bov can be a neccesity after all that's what they are designed for.
 
That's where most of the noise comes from. The BOV (well, it's actually a BPV, but sounds as loud as most BOV) noise is loud from my induction kit. The Injen intake does a much better job than the Hyundai stock kit does. I have controlled IAT and the piping is much smoother and has laminar flow- not like the corrugated and restrictive OEM piping with all the noise control bits 'n bobs.

It took some experimentation and work to get it right, but with my setup my IAT are lower (measured after a 45 min trip on the highway in light traffic on the same route measured day-after-day going to work) than with the stock intake and the run is shorter and smoother. At the turbo inlet the the size of the intake is unchanged so intake air velocity is not reduced by the additional intake air- but more air is being introduced by the less restrictive setup. I read a lot about how a pod filter HAS to let in more dirt since it has higher flow. Bullshit. The pod filter has increased area through which to suck air- that's the the gain in intake air volume. A high quality oiled cloth filter material will filter just as much as a paper filter. If you have a cheap induction kit and don't address the potential shortcomings you will gain nothing and have increased dirt being introduced to the system. However, with a little reflective tape, a heat shield, some exhaust wrap and a basic understanding of what you're trying to do you can make something much better than the OEM intake. Doing the job properly means taking high quality base materials and doing the rest yourself. That's what real car guys do.

As for getting a pair.... that from the guy who won't do 80-100 MPH times.... OK.
 
IMO Guybo mate you are sadly mistaken on the size of OG's pair given he intends to strap himself into a turbo powered rocket that he has drilled so many holes in that I fear for his safety ;):)
 
That's where most of the noise comes from. The BOV (well, it's actually a BPV, but sounds as loud as most BOV) noise is loud from my induction kit. The Injen intake does a much better job than the Hyundai stock kit does. I have controlled IAT and the piping is much smoother and has laminar flow- not like the corrugated and restrictive OEM piping with all the noise control bits 'n bobs.

It took some experimentation and work to get it right, but with my setup my IAT are lower (measured after a 45 min trip on the highway in light traffic on the same route measured day-after-day going to work) than with the stock intake and the run is shorter and smoother. At the turbo inlet the the size of the intake is unchanged so intake air velocity is not reduced by the additional intake air- but more air is being introduced by the less restrictive setup. I read a lot about how a pod filter HAS to let in more dirt since it has higher flow. Bullshit. The pod filter has increased area through which to suck air- that's the the gain in intake air volume. A high quality oiled cloth filter material will filter just as much as a paper filter. If you have a cheap induction kit and don't address the potential shortcomings you will gain nothing and have increased dirt being introduced to the system. However, with a little reflective tape, a heat shield, some exhaust wrap and a basic understanding of what you're trying to do you can make something much better than the OEM intake. Doing the job properly means taking high quality base materials and doing the rest yourself. That's what real car guys do.

As for getting a pair.... that from the guy who won't do 80-100 MPH times.... OK.

I can't disagree with any of this :)

Playing around with a car's intake system is a good way for beginners to start on the long and painful modding road. It is relativley cheap, doesn't affect the car's safety like bad brake and suspension mods can and is easlily reversable.

I won't be doing 80-100 testing for a couiple of reasons:

IMO it has no bearing on real life road performance. As mentioned before, I consider 40-70 a more useful indication of a car's performance as this is what the car will be doing more often.

The national speed limit in the UK is 70 so testing 80-100 is just plain stupid, again, IMO.

Hopefully, my road legal drag car will be up and running next year (mind you, I have been saying that for a few years). Theoretical 1/4 terminal speed will be 150-160 so I won't be spending much time between 80-100 and will be too busy to measure it:)
 
Yeah, that looks good to me. Do you want to do the honours?

I would if I could see how to do it ;) I suggest we start from your post?

In real world terms we can probably consider 80mph to be a reasonable transient speed to hit briefly during a swift main road passing manoeuvre. Less time on the wrong side of the road is a good thing. I doubt that many traffic officers would bother any of us for this alone.

I agree that 100mph is asking for attention and if we need to hit that speed to pass safely then we probably don't need to overtake in the first place
 
"I consider 40-70 a more useful indication of a car's performance"

I very much agree and wish they would quote this on car specs also.

Two cars of similar weight and power will have similar 0-60, regardless of torque.

However they'll have very different in gear times, like 3rd gear 40-70, based on their difference in torque.
 
"I consider 40-70 a more useful indication of a car's performance"

I very much agree and wish they would quote this on car specs also.

Two cars of similar weight and power will have similar 0-60, regardless of torque.

However they'll have very different in gear times, like 3rd gear 40-70, based on their difference in torque.

Yep. When we looked at our Golf the TSi and TDi had same power. 0-60 the petrol TDi was 0.2 seconds quicker. The 40-70 in 4th gear though the TDi was 3 seconds quicker! No brained for me in the decision and I've just did a 250 mile round trip yesterday to London, mix of M3 motorway and city driving and I returned 62mpg overall which I was well happy with as I made excellent time not really going over 70 speed limit except couple of times to despatch a long queue of juggernauts.
 

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