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Sizes for the standard side mount intercoolers?

Discussion in 'A3/S3 Forum (8L Chassis)' started by S3 Paul, Aug 10, 2009.

  1. S3 Paul
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    S3 Paul Active Member

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    Can anybody who has changed their intercoolers to a front mount please help me out?
    Im trying to find out what size they are as i have a number of options for a front mount cooler but some seem too big, Others seem too small...
    So basicaly, im looking to work out the volume of the stock set up ( both side mounts and the long link pipe that runs under the car,

    Some people i know say that a larger cooler would be best as less preasure drop and the air will simlpy take the path of least restriction.
    I said ye but what about the "lag" they said its not realy "lag" as such you on about, Its the responce of the throttle inbetween gears and such ( he did give it a posh name but i cant remeber )
    Basicaly they said at say 1 bar of boost (asuming 100% efficency ) at 3000rpm the engine would consume 60 ltr of air a second.
    Meaning that if a cooler and pipe work set up was as big as say 30 ltr it would take 0.5 seconds to fill the system from vacum ( very rearly would you see vacum conditions between gears as you would be at higher rpm that the 3000 mentioned )

    Then theres the pipe work do people use 51mm pipe simply because it fits better? i was told maybe something like 57mm on the hot side and 65 on the cool side would be best??
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  2. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    I have mine sat in a box at home so I can measure them tonight when I get home...

    IIRC, the OEM SMICs actually use 2 x 30mm cores side by side.. I'll try and get a pic too..

    The 51mm piping is used on the Forge (and my AH Fabs) FMIC as it is really the only way a FMIC can be fitted without modding the hell out of the bumper and losing the fogs.

    Larger 60mm (same dia as OEM piping) ends could be used but I suspect the bumper won't fit back in the original position and is why people using ebay style FMIC's tend to end up with pipe work hanging out of the fog light grille area.

    Can't say I have noticed anything but improved response and consistant performance since fitting my FMIC, running the size it is and 51mm pipes stepped down from the MAP sensor housing and charge pipe. Things may be different when I get the GT30 on but I guess we will see what happens then.

    Will post up pics and sizes of the SMICs later..

    (nice touch on the sig btw ;P... lol)

    <tuffty/>
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  3. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    Righty...

    Dimensions of the SMICs is as follows...

    Width across core is 176mm, length of cores (to end tank plates and not including end tanks) is 200mm, depth is 85mm.

    Look like this..
    [​IMG]

    ...and have 2 x cores looking a bit like this...

    [​IMG]

    ...and this...

    [​IMG]

    Hope that helps..

    <tuffty/>
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  4. S3 Paul
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    S3 Paul Active Member

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    Top banana,
    Well im looking to get the cooler on at the same time as the engine goes in. Should be easier as most of the front end will be off any how.
    One of the coolers i have is slightly thicker than yours and one is over all slightly smaller.
    I am still unsure which to opt for
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  5. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    The core on my AH Fabs is 62mm... IIRC Glen (Ess_Three) had one that was 50mm (maybe 40mm?) and was still fine.

    I got the dimensions for the AH Fabs one from a post on the 8L forum... someone asked for the Forge core dimensions... I just used that as a start point...

    I did post a link on another FMIC thread (somewhere) to a page that had loads of the maths behind intercoolers and the like (can't fine it at the moment...)

    I would imagine if its somewhere handy to the surface area of the Forge/AH one then it will doo the job... if you already have the coolers then you may as well just try it... if it doesn't work then refit the OEM, bumper is a piece of cake to remove.

    Check for potential boost leaks though and measure (if you have access to VAGCOM) before and after intake air temps (block 118) which should give you an idea of how well the cooler is working to keep temps down.

    <tuffty/>
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  6. S3 Paul
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    S3 Paul Active Member

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    It was me that posted the forge sizes haha !
    Woulf a 75mm thick core fit behind the bumper??
    slightly shorter than forge and 300 high? i just hate guessing , Mine is planned to be running harder than a stock k04'd S3... thats why i gave the larger core a thought
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  7. S3 Paul
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    S3 Paul Active Member

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    [​IMG]
    these are the 2 coolers i have . the larger one is 450x300x75 and the smaller one is 450x230x65
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  8. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    Smaller one should be fine however you may have probs getting the pipework to fit with the bumper... what size outlets are on the end tanks?

    <tuffty/>
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  9. S3 Paul
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    S3 Paul Active Member

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    they are 65 in and out. i was thinking reduce it on the "hot side " to 51 mm and then on the colder side try to stick to 65 ?? because the core is shorter than the forge i hoped it would make things easier??
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  10. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    The problem isn't so much controlling the speed/pressure drop etc but physically fitting the pipework behind the bumper.

    To get it to fit it needs to tuck into the bit of the bumper under the lower grille area...

    [​IMG]

    You 'may' get away with using a 65mm to 51mm reducer and gain clearance. 14mm is quite a bit to close up gap wise but difficult to tell without offering it up and seeing.

    I took the grilles out when I was at AH to work out where the cooler would sit and what clearance I had... prob gonna be the same technique for you in this case. Make brackets that will allow you to fine tune the final mounting height with washers. I got AH to make the bracket on mine site underneath the crash bar so I could adjust down to the right height.

    Do photos and a write up for the FMIC sticky :)

    <tuffty/>
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  11. ianysm
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    ianysm Active Member

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    Is there much gain to be had by replacing the standard SMIC's with better quality SMIC's instead of all the work that goes into an FMIC?
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  12. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Right humour me here please guys, it's Friday afternoon and I had a beer at lunch!

    I was looking at the picture of the SMICs above and was trying to think if there was a way that they could be joint together by a pipe and used as a FMIC. The SMICs work fine, they're just in the wrong place.

    Ok stop laughing!!!

    I was thinking that if both SMICs were turned so that the inlets/outlets faced up, with a pipe joining the the two together in the middle then the other two ends will be facing upwards for the pipes to run towards the engine.

    Now, apart from the SMICs being 85mm thick and maybe a very tight squeeze to get behind a cut crash bar, what would the flow be like?
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  13. 1animal1
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    1animal1 The Clar!! it mouves!!!

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    westle im in exactly the same situation mate, 2 beers at lunch and my chair is feeling like bed!!

    erm i think the inlets and outlets are angled and would provide too much disruption to flow (if i had to guess after not seeing in flesh)...... although you could be the guinea pig mate haha - na seriously people are arguing about the internals of a single fmic nevermind 2 smics put together, the flow will be ****....4 end tanks for the air to contend with etc etc

    Paul, i love your nails mate.....they are fanatastic, which salon do you use ;)
    Last edited: Sep 18, 2009
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  14. ianysm
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    ianysm Active Member

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    I thought the reason for the FMIC wasn't just because its at the front and has better air flow to it, but more because its cores are larger creating more cooling?
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  15. Westy
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    Westy Double Dark Side! Diesel & 8P

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    When I come round to doing my FMIC (hopefully this year!) I'll see if there is room to mock up the 2 SMICs together and if there is i'll log some temps. If it was any good it will be an even cheaper alternative to the AH/eBay coolers.

    By the way I've had a few more beers and everything seems easy to do at the moment. Now i'm off to try and work out how to move my rear callipers to the front to increase breaking! :think::idea::beerchug:
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  16. ianysm
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    ianysm Active Member

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    Amazing what beer does to your head!!
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