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Author Topic: Intakes..... and more intakes  (Read 8098 times)

Offline PDT

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Intakes..... and more intakes
« on: June 03, 2010, 09:28:59 pm »
For the last few months we have been playing with intakes on both the K03 and K04 Golf GTi's. We first built a prototype of our own but we were dissapointed with the noise, its was all swooshing and wooshing, as if a hoover was fitted under the bonnet, but lacked that induction roar that most cars gain with a nice intake.

Another issue was the amount of noise at low throttle and low RPM, and lack of noise higher up the revs. This made 'everyday' driving a bit annoying if you wanted a subtle and quiet car t drive.

Our prototype was shelfed in favour of a panel filter, but performance dropped as expected. This was replaced shortly after with a Forge Twintake, kit fitted fantasticly well, performed well and sounded OK but was by no means quiet. We expected the enclosed filters to help, but they didnt.

Next up was a Dbilas, which is built extremely well and up to the usual Dbilas build quality that we expected but once fitted we did notice the car was far less  eager to pull at low RPM, the dyno also confirmed this with a loss of 20bhp over the Forge item! Once we investigated where the power had 'gone' it was clear it was the tiny airbox with a smaller filter than fitted to most petrol lawnmowers!

But the plus point was that the wooshing 'henry hoover' noises were gone. So off came the airbox to be replaced with an open cone (universal item we keep in stock) and road testing was impressive, no swooshing noises and lots of eagerness that we had lost with the airbox fitted. The dyno confirmed this as did the datalogs and power was 4bhp higher than with the twintake fitted. The setup sounded fantastic on the road, perfromed well on the road and dyno and logs look better than both the twintake and dbilas kits individually.

The conclusion is that if you want a quiet intake, its not the type of filter as in enclosed vs open, its the material that the intake tubing is manufactured from. The Forge item is made from very thin aluminium, the Dbilas is rather thick cast alloy. The thickness of the tubing dampens the noise of the rushing air. I think the ideal solution would be for a manufacturer to bring out an inlet which has all of the benefits of the Forge kit but with the a heavier gauge intake tubing, this will give the power gains, the quality and the silly swooshing noises will be eliminated. Or just buy the Dbilas kit and a universal filter :)

Offline bacillus

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Re: Intakes..... and more intakes
« Reply #1 on: June 03, 2010, 09:41:38 pm »
Interesting results...
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Offline Top Cat

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Re: Intakes..... and more intakes
« Reply #2 on: June 03, 2010, 09:42:18 pm »
Yes about 20 minutes to late.  :fighting: :fighting: :fighting:

Offline SteveP

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Re: Intakes..... and more intakes
« Reply #3 on: June 03, 2010, 09:44:42 pm »
Still the Dbilas kit has the wrong size MAF housing doesn't it?
 

Offline keith

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Re: Intakes..... and more intakes
« Reply #4 on: June 03, 2010, 09:47:08 pm »
what filter do you recommend for the dbilas as i have had a hankering to open mine up and see what lurks inside.

Offline big_pete

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Re: Intakes..... and more intakes
« Reply #5 on: June 03, 2010, 10:20:17 pm »
What a great post PDT, this is what I wanted to do on a dyno testing intakes to find the best, you have just saved us all lots of money and time.
I wanted to develop what we all seem to be looking for.
Great post, keep us updated.

Offline john_o

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Re: Intakes..... and more intakes
« Reply #6 on: June 03, 2010, 11:00:04 pm »
nice but Id need to be convinced its better than the ITG/twintake, equal may be but not better.
what was the open cone make?
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Offline disco stu

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Re: Intakes..... and more intakes
« Reply #7 on: June 03, 2010, 11:15:44 pm »
hhmmm I feel empty inside now reading that, seen as I bought your Twintake Steve!!
Still happy as larry though :driver:

Next Revo stage1 i think

Offline Janner_Sy

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Re: Intakes..... and more intakes
« Reply #8 on: June 03, 2010, 11:36:27 pm »
could you post up dyno runs of the various diferent intakes you tried so we can see how they compard across the entire rev range, and of course pics of this new hybrid intake, because if its quiet im interested :party:

Offline PDT

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Re: Intakes..... and more intakes
« Reply #9 on: June 04, 2010, 03:58:37 pm »
what filter do you recommend for the dbilas as i have had a hankering to open mine up and see what lurks inside.

Pipercross universal is a good option, loads of sizes available and cost around £50



could you post up dyno runs of the various diferent intakes you tried so we can see how they compard across the entire rev range, and of course pics of this new hybrid intake, because if its quiet im interested :party:


I will post up some graphs when I get a chance to get them scanned in.


As for the MAF housing comment, this is a myth started by certain software providers so that you buy certain intakes. (in my personal opinion)

Offline Janner_Sy

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Re: Intakes..... and more intakes
« Reply #10 on: June 04, 2010, 03:59:47 pm »
can you take a pic of the new filter setup please mate, cant quite picture how this new intake looks and where the filter is?? :happy2:.

the internal diameter issue, was apparently solved with an insert, or so i hear
« Last Edit: June 04, 2010, 06:58:11 pm by vRSy »

Offline RedRobin

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Re: Intakes..... and more intakes
« Reply #11 on: June 04, 2010, 06:55:30 pm »
^^^^
Excellent and useful info, PDT  :drinking:

However, I think that the following are the considerations which people have when choosing an intake.. Different people want different things on the list (not in order of importance):

- Performance.
- Standard of manufacture.
- Ease of maintenance.
- Sound.
- Appearance aka 'Eye-Candy'.
- Price.

For me the Twintake is purrfect and I wouldn't want it quieter.


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Offline cupra_k1

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Re: Intakes..... and more intakes
« Reply #12 on: June 04, 2010, 07:24:52 pm »
As for the MAF housing comment, this is a myth started by certain software providers so that you buy certain intakes. (in my personal opinion)

Did you check the fuel trims in VCDS with each intake fitted? I can confirm you will see leaner fuel trims on an intake such as the Dbilas with a larger Maf housing than OEM (66.55mm) as the Maf sensor will be under reading. This isn't a major issue as the car is able to correct the mixture to a certain point (+/-25%), but will also throw a fault code once the trims hit +/-12% from memory.

The best option is to correctly scale the Maf housing by sleeving it as i did to good affect, which in turn improved airflow readings.
« Last Edit: June 04, 2010, 08:23:50 pm by cupra_k1 »

Offline Janner_Sy

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Re: Intakes..... and more intakes
« Reply #13 on: June 04, 2010, 07:41:24 pm »
where abouts do you get these sleeves??

Offline cupra_k1

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Re: Intakes..... and more intakes
« Reply #14 on: June 04, 2010, 08:21:56 pm »
where abouts do you get these sleeves??

I just bought some 2 3/4" 16SWG aluminium tube off ebay and fabricated it myself mate.