DIY S55 Water/air intercooler retrofits for N54/N55

[Sticky]

Ran across this guy who did this a while ago and another guy attempting it.

The obvious idea is to retrofit the S55 setup but easier said than done.

Just a heads up. I recently completed the install of a A2W intercooler on a 2012 135i and wanted to provide some lessons learned and feedback, mainly for peers who search for this info later on. Key take aways:

1. the S55 intercooler, tank, etc all pops onto the existing N55 manifold
2. The throttle body pipe fits but does not use the retainer that the N55 comes with it. Youll need that white expander to use this, or make your own
3. You can use either TMAP location. You will need to extend the wires to get to the S55 one on the intercooler (which is what I did) then I use a stock one to block the whole int he customer charge pipe which also allows me to plug and play if I want to go from 3.5 to stock TMAP.
4. I used a 24" x 12" heat exchanger. Cut a bunch of plastic, made mounts to attached to the top 2 bolts of brackets that support upper bumper. also made mounts to mid section to plastic remaining structure. Tilted with bottom further in by 2 inches. This BARELY fit. Make sure to test fit with bumper.
5. I used a OEM bosch water pump, same common pump many OEM uses, I think its the same as the cobra. I mounted the pump in the area opposite the oil cooler. I mig'd up a aluminum mount that bolts to the front bumper rail (2) bolts. I used rubber to mount it. Attached to exchanged and OEM intercooler lines.
6. I used the OEM S55 (2) piece engine cover to make the install clean looking

The hard part:

7. You need to re-route the intake. I could have left it on the turbo side but opted to move it. I took THe F series route. I tried using a BMS F series intake but IT DOES NOT fit. It was close but its a hard no. I make my own from aluminum. I mounted the OEM sensor tangent the old one, (the wires actually fit).
8. Valve cover vent. You need to get the valve cover a vent and there is a little stupid heater in place that I opted to leave functional to avoid CELS. I used the F series inlet and vent tube and it worked like a charm.
9. You need to fab piping to go from turbo outlet to intercooler. Since I was using a EFT kit, the outlet already points up. If it was a PS2 youll need to fabricate a bend.

Parts needed:
A. 3" and 2.5" aluminum pipe kits with couplings :150
B. S55 intercooler with tank, mounts, lines, and charge pipe : 350
C. 24x12 heat exchanged: 150
D. pump : 100
E. Mig welder with spoolgun: 500
F: a bunch of lines, fittings, etc: 100

So if you have the welder already its a total of 850. the heat exchanger is larger than OEM bmw. The N55 runs lower revs and typically less power, should be plenty of cooler (especially with meth) for any N55 platform. Should also spool better, have better transient response, and much less boost loss across the core.

I will put together some pics and videos seperately after the dif and SSP clutch installs and tune. This might be some time. Wanted to make sure I dont get lazy and not post this info later.

And:

Hi all, I have been wanting to do a water to air street build for a while, I realize that this is not the best way to spend my money to make the most power per $. I am a mechanical engineer, and for whatever reason, this project interests me the most. I like the idea of having the output paths similar for both turbos and the other *potential* benefits that this system could provide. This is going to be a slow project, as my day job and marital obligations wind up leaving me with little free time. If you are a person or a vendor who wants to replicate the project, I may be able to provide some guidance, I have no intent to commercialize the design. If you do commercialize it and make a better design, all that I ask is that you give me a discount on the final product!

Potential benefits:
1)The reduced charge pipe volume will slightly improve throttle response
2)The reduced travel distance, number of bends, and length of travel through the A2A intercooler may provide some marginal high rpm performance gain for stock turbos due to the reduction in pumping losses.
3) Possible sub-ambient cooling at some point in the design

Potential drawbacks:
1) Weight
2) System Complexity
3) Cost

My first selection was the intercooler itself. I searched far and wide for Water to Air intercoolers, and I was never really satisfied with my options. Out of sheer frustration, I decided to try the most obvious choice (OEM M3). I liked that it had dual inlets with internal turning vanes to guide the airflow, had demonstrated good performance, and was made to work on a car that had a similar engine layout.

To my surprise, it was not a close fit, it was an exact fit! It neatly mounts directly to to the stock intake manifold with the same rubber shock-absorbing mounts that the airbox uses!

But there is no way that the hood will close with that thing in there right?

Wrong! Hood closes fine and with room to spare. Attached are some photos that I have taken showing the clearance remaining after shutting the hood. (this is for a LCI e90)

As you can see, the OEM expansion tank will also not require any modifications.

[maxnix]

Kind of shocked no high HP modifiers have evidently chosen this set up.

[Sticky]

Kind of shocked no high HP modifiers have evidently chosen this set up.

It's odd, isn't it? Especially considering you don't even need to go with the OEM design but you can jump straight to aftermarket coolers.

[Chancess]

It sticks up pretty high compared to the S55, is there any way to make it more flat?

[Torgus]

I think it is neat but I am not sure it is worth the hassle. A large IC + meth works just fine and is much less complicated with less points to fail.

[maxnix]

But there are no invisible flames with this set up. And you won't have to be explaining anything to your insurance company if something happens.

[Torgus]

But there are no invisible flames with this set up. And you won't have to be explaining anything to your insurance company if something happens.

The 1st post mentions/suggests using this A2W IC and meth together for best results.

Meth is very safe as long as you install it correctly. My points in my last post remain unchanged: less expensive, less complicated and more reliable, better results.

It's in Bantam's post he specifically says Drawbacks:
1) Weight
2) System Complexity
3) Cost

Lets add weight, cost, and complexity(and more failure points) to an n54.

Bantam goes on to say this is not really the best way from a $$$ perspective and the listed benefits are marginal over a FMIC. The fact you need to fabricate parts to make this work and it costs more than IC + meth? For 99% of people it does not make sense to go this route and again a large FMIC + meth is simpler, has significantly more gains all around, and is a fraction of the price requiring no fabrication.

To each their own.

[F87Source]

Meth is very safe as long as you install it correctly.

Not entirely true, if you perfectly install a garbage meth kit with a garbage controller and garbage hardware then it won't matter. If something goes wrong your engine is done.

If you use good quality hardware, and a good controller then you will be fine. Currently there is only 2 controllers on the market I would classify as good: Aquamist HSF4 and torqbyte cm5 lts. Maybe the motive reflex - but I don't know enough about it yet.

[Torgus]

Not entirely true, if you perfectly install a garbage meth kit with a garbage controller and garbage hardware then it won't matter. If something goes wrong your engine is done.

If you use good quality hardware, and a good controller then you will be fine. Currently there is only 2 controllers on the market I would classify as good: Aquamist HSF4 and torqbyte cm5 lts. Maybe the motive reflex - but I don't know enough about it yet.

100% Correct. I when I said 'install it correctly' I meant using only compression fittings, no push locks. Use a SS braided meth line and run it correctly not where it will get pinches or likely to contact anything warm. Use the right type of nozzles for your application i.e. checkballs in them if you need them. Install the meth bungs correctly and in the correct locations, calculate the about of nozzle you really need when factoring in your max boost, etc. etc.

I would add JB4 to your list. I can't imagine the reflex would have problems given how advanced it is and we are just sending a signal to a pump. Worst comes to worst the controller dumps meth when it shouldn't or does not inject when it should. When I said safe I was thinking mainly in response to the 'invisible flames' comment above. It might not be safe for your engine if your tune is relying on the meth for fuel and you run super lean because you have a $#@! controller! I have the HS4 and it is a great kit.

[BoostHaus]

Yeaaahh, this doesn't seem worth the time, effort and money at all to me

[F87Source]

100% Correct. I when I said 'install it correctly' I meant using only compression fittings, no push locks. Use a SS braided meth line and run it correctly not where it will get pinches or likely to contact anything warm. Use the right type of nozzles for your application i.e. checkballs in them if you need them. Install the meth bungs correctly and in the correct locations, calculate the about of nozzle you really need when factoring in your max boost, etc. etc.

I would add JB4 to your list. I can't imagine the reflex would have problems given how advanced it is and we are just sending a signal to a pump. Worst comes to worst the controller dumps meth when it shouldn't or does not inject when it should. When I said safe I was thinking mainly in response to the 'invisible flames' comment above. It might not be safe for your engine if your tune is relying on the meth for fuel and you run super lean because you have a $#@! controller! I have the HS4 and it is a great kit.

Also run filters, just in case.


In terms of why I don't know if the reflex kit is good yet, is if it supports additional sensors such as a flow sensor. This is critical imo, because if you have a leak down steam the flow sensor will detect it and trigger a fail safe long before the engine knocks. Torqbyte is developing an IR flow sensor as well which will be even more accurate than the traditional wheel flow sensor, so I'm excited for that.


In terms of jb4, there really is no need on a properly flashed tuned car with a good meth controller. I used to run jb4 back in the day on my m235i, but imo flashing has gotten so good piggy backs don't add any value anymore.

[Eleventeen]

Water-to-air will not lower IAT’s any more than air-to-air unless you are running a reservoir that allows you to fill with ice. Otherwise, both systems are limited by the ambient temp. If you’re running enough water in the system, it will keep IAT’s from creeping up as quickly, however it also takes longer to recover after a pull. So as previously posted, this mod is not worth the effort (or extra weight). Looks like he did a really good job on this install, though!

[Dumaurier7]

I did it on my 235 because I had to, you guys are making statements that you cannot prove or support with hard data. At the moment I'm only running 8 psi boost and my intake temps stay between 38 and 42 degrees C, I will be posting facts when I eventually get the boost up

.

[F87Source]

I did it on my 235 because I had to, you guys are making statements that you cannot prove or support with hard data. At the moment I'm only running 8 psi boost and my intake temps stay between 38 and 42 degrees C, I will be posting facts when I eventually get the boost up

.

Not to be a douche bag, but those iat numbers are really really really bad for 8 psi of boost. My m2 on 16 psi of boost and a bms intercooler doing back to back pulls at 24C ambient gets to 45C tops, and these numbers are pretty average with a 5" step core intercooler with a large intercooler these numbers get even better. At steady state my IAT's do not get hotter than 38C and thats with a 30C ambient temperature.


What conditions are you getting these IAT's at? Steady state? Pulls? What is the ambient temperature?

[Eleventeen]

I did it on my 235 because I had to, you guys are making statements that you cannot prove or support with hard data. At the moment I'm only running 8 psi boost and my intake temps stay between 38 and 42 degrees C, I will be posting facts when I eventually get the boost up

.

Thermal dynamics can in fact be proven. Water and air both absorb heat and both are merely a vehicle for transferring heat from the intake charge to the atmosphere. Although liquid absorbs heat better than air, you are still limited by how much heat the atmospheric air can absorb from your heat exchanger. AIR —> LIQUID —> AIR is the same result as AIR —> AIR when it comes to IAT’s. There are advantages and disadvantages to both.

[Dumaurier7]

[QUOTE=F87Source;866521]Not to be a douche bag, but those iat numbers are really really really bad for 8 psi of boost. My m2 on 16 psi of boost and a bms intercooler doing back to back pulls at 24C ambient gets to 45C tops, and these numbers are pretty average with a 5" step core intercooler with a large intercooler these numbers get even better. At steady state my IAT's do not get hotter than 38C and thats with a 30C ambient temperature.


What conditions are you getting these IAT's at? Steady state? Pulls? What is the ambient temperature?[/QUOTE

I wouldn't call you names but you are clearly not objective or fair with your statement, I am very happy that you intercooler performs as well as you claim it does but I do not ever experience 24 deg. C days, I am located in the Caribbean and the average ambient temperature here is between 32 and 35 degrees C. The important factor in any type of intercooler system is the delta T. , anything under 20 degrees is excellent.

[F87Source]

[QUOTE=Dumaurier7;866628]

Not to be a douche bag, but those iat numbers are really really really bad for 8 psi of boost. My m2 on 16 psi of boost and a bms intercooler doing back to back pulls at 24C ambient gets to 45C tops, and these numbers are pretty average with a 5" step core intercooler with a large intercooler these numbers get even better. At steady state my IAT's do not get hotter than 38C and thats with a 30C ambient temperature.


What conditions are you getting these IAT's at? Steady state? Pulls? What is the ambient temperature?[/QUOTE

I wouldn't call you names but you are clearly not objective or fair with your statement, I am very happy that you intercooler performs as well as you claim it does but I do not ever experience 24 deg. C days, I am located in the Caribbean and the average ambient temperature here is between 32 and 35 degrees C. The important factor in any type of intercooler system is the delta T. , anything under 20 degrees is excellent.

That's why I asked what your ambient temps and if it was under steady state to be more fair... Initially I thought you had around 25C temps in that case it was really bad, even at 32C ambient a 10C delta is kind of high with only 8 psi of boost. This either means your pump speed isn't high enough or your hear exchanger is too small.

And it's under 20F delta which is considered to be excellent, not 20C, a 20C delta is horrible.


Also there's an f30 n55 owner with an air to air intercooler that was able to hit 5F delta at steady state, now that's impressive.