Adding auxiliary radiator

[GTI Jake]

I'd love a Baun, thing are like pieces of art and I love staring at them. Need to do a flash sale my man!

No sales or discounts ever, unlike all my Chinese competitors I don’t have mark up to dip into.

This is why eventually I’ll move onto a higher end platform that can support the more expensive components I use with an actual profit to be made. Building mk7 parts I make exactly what I make at my real job hourly, except at my real job I can hang out on the forums chatting with you guys and building mk7 parts I’m in a freezing cold or 100*F shop working my ass off. I only do it because I enjoy it, and love pushing my skill set further as a challenge. Working an extra 10-40 hours a week on top of my 40 hours with the airlines puts a lot of strain on my personal life so it’s definitely a labor of love.

 

[Keehs360]

He lives to Troll people, and got slightly butt hurt I didn’t send him a free FMIC to test.

He loves to offer a $300 reward for the “best intercooler” just to talk down to random people on the internet who don’t know engineering vocabulary words (he’s an engineer).

I like that he spends the time to try to help people, and don’t have a problem with him, but I don’t endorse that kinda nonsense...he could just tell them he’s the one who posted the data they’re referring to.


Yeah it’s during shifts which is also a vacuum (another possibility for error in the readings). During the pull 2-12* over is average for my FMIC in 3-4th pulls at or below 100* ambient.




On Mk7.5 (2018 and newer). Prior to that it was a big or radar in the lower grille

Sounds about what I saw, during a dsg 60-100 pull temps only climbed 6 or 7 degrees F. He let off the gas and like 2-3 seconds later it was ambient again LOL

 

[Keehs360]

No sales or discounts ever, unlike all my Chinese competitors I don’t have mark up to dip into.

This is why eventually I’ll move onto a higher end platform that can support the more expensive components I use with an actual profit to be made. Building mk7 parts I make exactly what I make at my real job hourly, except at my real job I can hang out on the forums chatting with you guys and building mk7 parts I’m in a freezing cold or 100*F shop working my ass off. I only do it because I enjoy it, and love pushing my skill set further as a challenge. Working an extra 10-40 hours a week on top of my 40 hours with the airlines puts a lot of strain on my personal life so it’s definitely a labor of love.

Honestly you’re not wrong. I’d recommend the Porsche and vette platforms.

 

[GTI Jake]

Honestly you’re not wrong. I’d recommend the Porsche and vette platforms.

Probably whatever I or one of my close friends buys. Trying to get development cars from strangers is more trouble than it’s worth as proven by the Mk7/7.5 R crowd.

 

[Keehs360]

Probably whatever I or one of my close friends buys. Trying to get development cars from strangers is more trouble than it’s worth as proven by the Mk7/7.5 R crowd.

Makes sense. I guess you’re just gonna have to buy a gt3

 

[GTI Jake]

Makes sense. I guess you’re just gonna have to buy a gt3

I wish lol, our seven year old would shit (that’s his dream car).

 

[AceHammer]

Didn't expect this to gain this much traction lol, I would like to try out an FMIC but as far as I know, there's none that fit the A3/S3.
I do want to point out though that my IAT temps with a magic ebay intercooler are fine imo, I was just looking for ways to drop coolant and more directly dsg temps.

I did look into the CSF radiator, but I am highly skeptical that it will fit with my IC.

I had the car apart today to do a carbon clean and went over the coolant lines and it appears to be a fairly simple mod. I also found what looks like a CSF replica radiator for 150, which when added in with the bracket and hoses should only total up to around 250 dollars.
Will this add-in another failure point in the coolant system yes, but I haven't heard of any s3s having issues with this and it has the benefit of being an OEM solution.

 

[Keehs360]

Didn't expect this to gain this much traction lol, I would like to try out an FMIC but as far as I know, there's none that fit the A3/S3.
I do want to point out though that my IAT temps with a magic ebay intercooler are fine imo, I was just looking for ways to drop coolant and more directly dsg temps.

I did look into the CSF radiator, but I am highly skeptical that it will fit with my IC.

I had the car apart today to do a carbon clean and went over the coolant lines and it appears to be a fairly simple mod. I also found what looks like a CSF replica radiator for 150, which when added in with the bracket and hoses should only total up to around 250 dollars.
Will this add-in another failure point in the coolant system yes, but I haven't heard of any s3s having issues with this and it has the benefit of being an OEM solution.

Vw and Audi add those smaller radiators so they won’t have to buy a different size from borg Warner, bosh or whoever the hell makes them. the aux set up is a cost cutting measure

An aux radiator imo isn’t the best way of going about it. Honestly I’d look for higher static pressure radiator fans before adding an aux radiator

 

[GTI Jake]

Didn't expect this to gain this much traction lol, I would like to try out an FMIC but as far as I know, there's none that fit the A3/S3.
I do want to point out though that my IAT temps with a magic ebay intercooler are fine imo, I was just looking for ways to drop coolant and more directly dsg temps.

I did look into the CSF radiator, but I am highly skeptical that it will fit with my IC.

I had the car apart today to do a carbon clean and went over the coolant lines and it appears to be a fairly simple mod. I also found what looks like a CSF replica radiator for 150, which when added in with the bracket and hoses should only total up to around 250 dollars.
Will this add-in another failure point in the coolant system yes, but I haven't heard of any s3s having issues with this and it has the benefit of being an OEM solution.

Don’t get me wrong there’s nothing wrong with a direct replacement intercooler, basically all aftermarket intercoolers are a massive improvement over OEM.

The point is that’s a lot of extra installation labor vs a FMIC, and the BS about FMIC being insufficient just plain old isn’t true. (Not saying you said that)

For $250 it’s worth trying that aux cooler, just make sure you have proper air flow to and from it by way of bumper and fender liners modifications or OEM+ replacements. You’ll see some kind of benefits, but without testing it would be pure speculation as to how much.

 

[AceHammer]

Oh yea, if there was an FMIC kit for the a3 I would have bought that over a sandwich-style as that install was a PIA. I would love to do the driver-side one, as on the S3/Golf R the coolant flows through it before going into the DSG heat exchanger, however that would require me to delete the sai pump.


Just planning on dremelling out the plastic in between the fins for an air opening, and as far as I can tell it should just require pulling the bumper bolting in the bracket + rad, at least on a 2015 a3 there's obvious unused mounting holes, and then plugging in two coolant pipes.

I know there are probably more effective ways to do all of this but my goal for this was to find a cheap and easy solution.

 

[jimlloyd40]

Oh yea, if there was an FMIC kit for the a3 I would have bought that over a sandwich-style as that install was a PIA. I would love to do the driver-side one, as on the S3/Golf R the coolant flows through it before going into the DSG heat exchanger, however that would require me to delete the sai pump.


Just planning on dremelling out the plastic in between the fins for an air opening, and as far as I can tell it should just require pulling the bumper bolting in the bracket + rad, at least on a 2015 a3 there's obvious unused mounting holes, and then plugging in two coolant pipes.

View attachment 204622View attachment 204623

I know there are probably more effective ways to do all of this but my goal for this was to find a cheap and easy solution.

Why don't you want to remove the SAI pump?

 

[AceHammer]

Right now the car is registered in Mass and I have a catless downpipe + spacer, I can pass emissions with 1 readiness monitor incomplete (The secondary O2 sensor). Removing the SAI pump would cause me to have 2 incompletes which would cause me to fail

 

[CaptainRatty]

I wish lol, our seven year old would shit (that’s his dream car).

That kid is going places!

 

[AceHammer]

Well spent a few hours looking over various photos and diagrams (The VW parts site sucks) and came up with a list of parts and cost.

Pretty much everything matches up except the Lower radiator coupling, I'm about 90% sure that this is the correct part based on engine codes, but would need an R owner to confirm for 100%

Right Side Rad - Prices for new OEM parts from https://www.audiusaparts.com/

Air duct - 5G0117334 - 20

Upper radiator coupling - 5Q0-122-291-CT - 25

Lower radiator coupling - 5Q0-122-291-DS - 116, This comes with a new temp sensor hence the high price. I have found ones on eBay for 60 dollars, but I am still looking for one without the sensor

Mounting bracket - 5Q0121093FD - 65. There are several different revisions/styles of this. This is the most recent as well as the cheapest.

The actual radiator - L&R ALUMINUM AUXILIARY RADIATOR - 150, message the seller and ask for just one, sold as two for 284.

Water hose - 5Q0-121-051-K - 20

Water hose - 5Q0-121-101-N - 27

Cross tube - 5Q0-121-070-AP - 35

Gromets for the bracket 4D0-317-867-A 2x - 12

Bolt for the bracket N10471802 - 2

Washer for bolt N90225901 - 1

Hose clamps N-906-870-01 - 3x - 9

Hose clamps N-906-869-02 2x -9

Will also need a 6 in generic coolant line, as VW wants you to buy an entirely new upper coolant hose, rather than sell the smaller individual pieces of it.

All together would run me about 450, which at that price point I'm not sure it's worth it. I figured I'd leave this here just as a reference for anyone else to use. I'm gonna have to do some more research, and honestly might just take out the sai pump and do the left one as it is cheaper, easier, and should have a much greater effect on DSG temps.

​

 

[JerseyDrew77]

Food for thought, calling out people like DAP who claim direct replacement is superior;

Audi has the OEM intercooler up front where it belongs on everything but MQB...the sandwiched location is an economy car cost cutting technique (keep all Mqb the same, save money).

The same poor design is used on base golf, and all the VW SUV. They didn’t put it there because it was good for performance, it was a compromise decision.

My FMIC at 661 cubic inch core volume outperforms most direct replacements up to the point where the core volume/flow rate is overwhelmed (which only happens on cars with MPI fueled hybrids or full frame). For those guys there’s a bigger option, the V2 (which will require some bumper rebar trimming).

The original V2 prototype kept the 600whp R it’s on cool for hot lapped ten second passes last season, and will be back with around 700whp this year. Unfortunately that intercooler core was discontinued by the manufacturer, so it’s time to re start development with another core. At 808 cubic inches it’s substantially larger and will flow well enough to keep MPI fueled cars close to ambient.





I’ve got the rest of the cooling package handled as well, just waiting on the shop I outsourced it to

Ah, nobody here is claiming direct replacement is superior. It was the other way around. Also, do you really think the sandwich location was an economy car cost cutting technique? If so, then why did they keep it the same for the CSS and TCR models overseas? Hell, even the TCR race car doesn't have a fmic.