forge twintake air intake available end Aug 09

[gazbutS3]

yep, looks like K03

[RedRobin]

Hmmm....Well I've already got some of that gold tape ready to wrap.

looks to me like HKS have tried to smooth the 90 degree bends that every other intake has. Its a case of which is worse in IMO, smooth the bends out and risk some heat soak, or avoid the engine and have the sharp bends. Which gives the best results is open to debate

....I think you've hit the nail on the head there, gaz - Less bendy and shorter (and tapered?) route to the MAF. Also, the mushroom filter is served by both the front grill vent and from around the headlight area but not too close to the heat of it.

Bit of extra hassle if you need to change a coilpack though. Still, can't be much worse than taking the stock engine cover on and off.

[Dubtek]

Yep, K03....for now....

[warren_cox]

The 90 degree bends in the pipe are a BIG issue, and one of the ways ITG have tried to counteract this in their design in by maximising the intake piping diameter all the way up to the MAF (which has to be a defined diameter to give accurate readings: 67mm). Using larger diameter piping means that as the air has more space in which to flow through the corners there is less slowing of the air than with restricted piping.

By using thick silicone piping and a heat shield some of the intake air temps have been lowered slightly, but the lightweight pipework will need reflective taping at some point. I've been looking at the various options on the Agriemach site but feel the gold tape is probably still the best option.

Whilst keeping temps down in the CAI is a good thing, (as is reducing the disruption in the flow path of the incoming air to a minimum as the HKS solution appears to have done very well), I am next going to look at something similar to what is used in Subaru's, and get a spray bar fitted to the IC. I think chilling the intake air in the space MAY have a greater effect than dropping the intake temps through the CAI by a couple of degrees.

Plans to look at this are October, so I'll post back if it works well or not.

[Janner_Sy]

Thwn why not get water meth injection. does that not cool intake temps.

Im not sure about that gold reflective tape. id have to get some plain silver

[bacillus]

Twintake will come powder coated black as opposed to polished ally(I,m expecting on real soon).
This will help in dissipate heat.

Isn't a black surface the best absorber of heat??   

[RedRobin]

Twintake will come powder coated black as opposed to polished ally(I,m expecting on real soon).
This will help in dissipate heat.

Isn't a black surface the best absorber of heat??   

....And white the best reflector of heat?

That's what I thought too. Wearing a white Tshirt on a really hot day is cooler than black.

[joesgti]

seems a little expensive....

http://cgi.ebay.co.uk/HEAT-BARRIER-REFLECTIVE-GOLD-TAPE-2-x-30ft-010397_W0QQitemZ310166308530QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item48375a46b2&_trksid=p3286.c0.m14

but i suppose with 30ft we could all do our cars! 

[RedRobin]

The 90 degree bends in the pipe are a BIG issue, and one of the ways ITG have tried to counteract this in their design in by maximising the intake piping diameter all the way up to the MAF (which has to be a defined diameter to give accurate readings: 67mm). Using larger diameter piping means that as the air has more space in which to flow through the corners there is less slowing of the air than with restricted piping.

By using thick silicone piping and a heat shield some of the intake air temps have been lowered slightly, but the lightweight pipework will need reflective taping at some point. I've been looking at the various options on the Agriemach site but feel the gold tape is probably still the best option.

Whilst keeping temps down in the CAI is a good thing, (as is reducing the disruption in the flow path of the incoming air to a minimum as the HKS solution appears to have done very well), I am next going to look at something similar to what is used in Subaru's, and get a spray bar fitted to the IC. I think chilling the intake air in the space MAY have a greater effect than dropping the intake temps through the CAI by a couple of degrees.

....I'm assuming all your post is referring to the imminent ITG and not the Forge Twincooler.

Re the ITG, when you say "chilling the intake air in the space", do you mean in the space in which the ITG foam filter sits? Because if so, this could surely be significantly assisted by the addition of an inlet from the foglight panel via a flexi air hose (an easy mod) which would then blow/deliver cooler (but not artificially cooled) air into that space and additionally feed the ITG foam filter.

This additional air feed from below could possibly assist any type of high flow tubular intake which has an open filter in that 'front-of-battery' area (but obviously not the Forge Twintake). In theory it's virtually the same as those 'lollipop-on-a-stick' intakes which extend the filter cone lower down except that it would no longer have the disadvantages of exposing the cone filter to water ingress nor having a longer pipework route to the MAF.

Am I right in thinking that whatever temperature the air arrives at the turbo at, it will then be heated; But the cooler it arrives, the less heated it continues its journey?

Please someone correct me if I'm barking up the wrong tree.

[RedRobin]

seems a little expensive....

http://cgi.ebay.co.uk/HEAT-BARRIER-REFLECTIVE-GOLD-TAPE-2-x-30ft-010397_W0QQitemZ310166308530QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item48375a46b2&_trksid=p3286.c0.m14

but i suppose with 30ft we could all do our cars!  

....You should be able to pipe wrap 2 cars per roll, so about £44 per intake. It does depend on the design of the intake though because I don't think you would wrap the flexible silicone hosing sections.

Sorry Joe but the temptation is too great!.... www.4cheapgold.com

Gold always has been relatively expensive and never cheap - Even large countries have been established on the stuff!

[DaveB@Vagbremtechnic]

Always gets me how they narrow the pipe towards the inlet, thats a sure fire way to increase inlet temps. Boyles law and all that

[RedRobin]

Always gets me how they narrow the pipe towards the inlet, thats a sure fire way to increase inlet temps. Boyles law and all that

....Isn't it a matter of trying to achieve the best compromise between cooler inlet temperatures and the advantages (flow?) of narrowing/tapering?

[KRL]

The 90 degree bends in the pipe are a BIG issue, and one of the ways ITG have tried to counteract this in their design in by maximising the intake piping diameter all the way up to the MAF (which has to be a defined diameter to give accurate readings: 67mm)

This is a very important point and one of the things that has put me buying an EVOMS or the old Forge.  Here is a quote from golfmkv.com

Faulty MAF readings. Any alteration of the MAF housing diameter from it's specified size in the software will alter the readings. I just saw a link posted in another thread to an article written by Cobb Tuning. Check this out, it applies to our vehicles too for the most part:



Aftermarket Intakes
The use of Aftermarket Intakes on 2002+ Subaru factory-turbocharged vehicles
by Trey Cobb


How it works
One critical design feature of this system, which differs from those used on most other vehicles, is the installation of the Mass Air Flow (MAF) sensor into the Upper Air Cleaner Case - instead of its own housing which has been traditionally the case with MAF equiped vehicles. It is primarily due to this design feature that problems may arise from modifying the factory air cleaner system.

When changing the factory air cleaner system out for an aftermarket system, you are required to relocate this MAF sensor into the new system. Due to this relocation, we have now opened up the potential for problems to occur.

The Mass Air Flow (MAF) sensor is a critical sensor used by the engine management system. The job of the MAF sensor is to monitor the Mass of air that is entering across the intake system. This is important because all of the fuel, timing and other critical engine management decisions are based primarily on what the MAF is reading. If this reading is off, then so will the fuel, timing, etc which has the potential to cause poor driving conditions or worse, engine damage.

Potential Problems caused by Aftermarket Intakes

MAF Sensor Housing Size
The MAF sensor only samples a small portion of the air coming into the system. From that sample measurement, the engine management system can calculate how much air is actually entering the system because it knows the inner diameter of the MAF sensor housing it is sampling from.

If the MAF sensor housing inner diameter changes in any way, the calculation performed by the engine management system will be incorrect. This means that the amount of air actually entering the system will be different from what the computer thinks is entering the system. This is critical because the computer determines how much fuel and timing to run based on this value of air. When it's wrong, it can cause the engine to run richer, or leaner, than it should.

With aftermarket intakes, it's extraordinarily common for the piping used to have a different inner diameter than the MAF sensor housing incorporated in the factory air box. This is due to the fact that the exact inner diameter of the factory MAF sensor housing is different than what's commonly available in the standard metal piping used for aftermarket intake systems.

It is true that some aftermarket intakes show an increase in power when installed on a stock vehicle. This power increase is due to the fact that the aftermarket intakes have a larger inner diameter for the MAF sensor housing to mount into which in turn leans out the Air/Fuel mixture because of this error in calculating how much air is actually entering the system.

Please note this is NOT due to the fact that the aftermarket intake is so much less restrictive than the stock air box and therefore more air is getting in but rather that the computer does not know it's now sucking from a larger tube and therefore more air is getting in.

So to recap, whenever the MAF sensor housing size is increased compared to stock, more air will enter the system than the engine management has been calibrated for and you will run leaner. If the MAF sensor housing size is decreased compared to stock, less air will enter and you will run richer.

Fortunately, there are corrections that can be made for changing the size of the MAF sensor housing to allow the engine to run properly which we will discuss later on in this article.

Turbulence
In order to accurately measure the amount of air coming into the system, it is important for the air to flow smoothly across the MAF sensor. Any turbulence in this air flow will create errors in the amount of air measured versus what is actually entering the system.

In the factory air box, the Subaru engineers utilizes a smooth velocity stack style inlet and internal ribbing on the inner sections of the cases to dampen pressure waves and promote a laminar air flow into the MAF sensor housing. The MAF sensor housing itself is straight and smooth internally and positions the sensing portion of the MAF sensor properly in the air flow stream (ie: not offset to any angle left/right or up/down).

For aftermarket intake systems, turbulence across the MAF sensor is an all too common occurrence. Often times the MAF sensor is placed in close proximity to a bend, pipe joint, or weld. In the case of some hot air intakes (ie: Short Ram), the MAF sensor is mounted directly after a conical intake -- well before the air has a chance to smooth out.

When this turbulence occurs, the MAF sensor will suddenly see more or less air then it had previously. This will cause the engine management system to respond by making the engine run leaner or richer for as long as the error from turbulence occurs. The most noticeable driving characteristic associated with this would be a hesitation or flat-spot in the engine's power deliver. A worse case scenario would be the engine suddenly leaning out while under full throttle that resulted in engine damage.

Unlike the errors created by the different size of piping, there are no corrections one can make for an intake design that allows turbulence across the MAF sensor.

Other Considerations
The other issues to consider with upgraded intakes are the filtration capabilities of the element used, the chance for water ingestion or damage from road debris.

Location of the MAF sensor in terms of its distance to the inlet of the turbocharger (or some other point of reference) is not critical so long as the system is free from leaks. Having it too close to the turbocharger inlet can of course create errors from turbulence as can having the plumb-back line from the compressor bypass valve (aka blow-off valve) too close.

Potential Solutions
Now that most of the common problems associated with aftermarket intakes have been outlined, let's discuss what possible solutions there may be for those that run one.

When dealing with the issue of a different MAF sensor housing inner diameter, the best solution we've found is to simply recalibrate the factory engine computer for the new air flow. The factory engine management system has a rather large table of data that basically tells the computer how much air is coming in per sample read. By recalibrating this information, the engine will run correctly -- so long as there isn't also a problem with turbulence.

For those intakes that generate turbulence across the MAF sensor, there unfortunately is no easy solution. Since this turbulence can occur at different points in the power band, based on both engine RPM and engine load, all that can be done to make the engine run safely is to recalibrate the engine with a relatively rich overall tune. While this isn't the best for power, it will help protect the engine.

Conclusion
The best solution for an aftermarket intake will be either one that has been designed to use the stock inner diameter for the MAF sensor housing or one that has a tuning program behind it to support the change in MAF sensor housing size. If there is any turbulence in the design, however, this will negate any usefulness of the intake.

TechnobabbleAddendum
For those still looking for something a little more in-depth.

The MAF sensor generates 0-5V based on measured air flow. The engine management system then determines the actual air flow based on this sensor's voltage. This mass air flow value can be represented as g/sec or lb/min, based on your preference. The voltage vs mass air flow value is not linear but rather more exponential in form.

To correct for a change in size of the MAF sensor housing diameter, we must modify the mass air flow values held within the ECU for each given voltage. These values are defined approximately every 0.1V of the MAF sensor range.

There is also a limit to the amount of air that can be read across the factory MAF sensor when using the factory MAF Sensor Housing diameter. This limit is reached at approximately 38.64 lb/min (293 g/sec). Those with the ability to manipulate the ECU tables will be able to maximize the MAF's sensor capabilities up to 39.6 lb/min (300 g/sec) but that's the ceiling of the factory ECU's programming. Using our AccessTUNER technology, we actually have the ability to rewrite the ECU software for a limitless MAF sensor calibration.

The MAF sensor itself does not need to be considered a limitation, even in large turbo applications. All one has to do is simply run the appropriate size intake diameter to the turbocharger and recalibrate the MAF sensor for that intake's inner diameter. If someone cannot properly recalibrate the MAF, then the limitation is in the tuner…not the hardware.

Link to the thread:
http://www.golfmkv.com/forums/showthread.php?t=91500&page=8

Does the ITG intake also have an oval shaped housing for the maf like OEM?

[RedRobin]

....

Regarding the Forge Twintake - Although I have no doubt that Forge have very extensively tested this intake, I do seriously question whether every single one supplied will achieve an even and equal air flow as a result of the junction of those two pipes.

I suggest this on the basis of what I found with the Milltek quad pipes from the back box - A well engineered and manufactured 'Y' junction in the pipework but nevertheless one branch carried no gases whatsoever. Hence the version of independent pipes I've been testing now and is without any such problems, but several improvements. Of course the direction of flow was 1>2 rather than Forge's 2>1.

Also, wouldn't the superior flow of one pipe over the other cause a back draft in the 'inferior' pipe? It's understood that which pipe delivers a 'superior' flow to the other will vary according to vehicle speed and conditions etc. BUT.. I'm not an engineer and this may not matter anyway.

All fascinating stuff though

[RedRobin]

^^^^
What I just posted pales into insignificance in the MAF considerations which KRL just posted

Extremely educational post, KRL