I'm about to open a can of worms.
 
Last week I adjusted the calibration of the temperature sensors in my A2W intercooler system, and they are now very accurate, to within 1 degree in fact. I achieved this by obtaining the specs of the Adaptronic e1280s ECU's internal voltage divider circuit for the temperature inputs, then populating the calibrations based on the official datasheets for the sensors. I found that the calibration that I had before wasn't far off (about 2-4 degrees), but I wanted to make the calibration perfect for the next step.

Prompted by the recent warm weather, I decided last night that I would datalog another drive to generate some more results for my A2W intercooler setup. The ambient temperature was about 23 degrees C.
I already did this earlier this year, but last time the conditions were different, and as some of you may know I've been re-thinking my A2W system in recent months, so this time I wanted to determine if my setup needs improvement, instead of trying to prove that it is already sufficient.
So, here we go, a plot of the exact datalog retrieved from my ECU's onboard flash memory (note to future readers...this is with my OLD A2W intercooler setup):
 

 
Observations:
 
- 3 main boost events, at 8, 14 and 32 minutes in the log.
 
- As forum member 'cogs' mentioned last time, the slow decay rate of the temperature sensor readings in some low-throttle cases is a result of the thermal inertia of the sensors, rather than an accurate representation of the temperature. When on boost with heaps of airflow over the sensor, the reading IS accurate though, because the additional airflow causes the sensing element to heat up quickly.
 
- From 14-22 minutes on the log, I was cruising at 90-110km/h on the motorway, and the A2W coolant temperature can be seen reducing noticeably during that time
 
- Worst case air temp before intercooler 110 degrees C (after a few seconds at 20psi of boost), down to 57 degrees C after intercooler, which is OK but not great.
 
- For the first 6 minutes (and at least another 5 minutes before the log started), I was idling in the garage while mucking around with some unrelated ECU settings, and during this time the A2W coolant temperature heat-soaked from 23 degrees C all the way up to 38 degrees C...not good at all!
 
- I was also idling, at traffic lights, around 7, 12, 24 and 25 minutes in the log, and the A2W coolant temperature can be seen heat soaking during those short periods too.
 
- If the A2W coolant was closer to ambient temperature, as it would be with a heat exchanger at the front of the car, then the worst case post-intercooler temperature probably would have been down around 40 degrees C, or even less, which would be an excellent result. The intercooler barrel already appears to be doing a decent job, given the excessively high water temperature inside it.
 
So, after all that, what's the point of this post, and why did I mention a can of worms? Well, a number of people did try to talk me out of having my A2W heat exchangers in the engine bay, instead of having one at the front of the car like everyone else. I'm basically here to admit that I should have listened, and I'm sorry that I didn't. Everyone knows I want everything to be just right on my car, so there is no point for me to hide my regret hahaha. I must emphasize that I am entirely happy with how the car drives and the substantial power that it already has, and if I never analysed any log files to look at the temperatures I would have no reason for concern, but being the perfectionist that I am with my car, and with the irrefutable results shown above, I now feel that I may make a change to my setup after all.
 
For those of you who warned me right from the start, please don't rub it in and make me frustrated...please just be happy that I have taken the necessary analytical steps, and I am considering making some changes to my setup. I just have to try not to feel regretful for not doing it right the first time lol.
 
Another bonus of this post is that it highlights the major heat soak disadvantages of having an A2A intercooler in the stock side-vent location in the engine bay (an A2A intercooler in that location would be affected by heat soaking in a similar way to my A2W heat exchangers, although maybe not as badly because there is no water being heated inside an A2A).
Also, once (if) I make some changes to my setup and post the new results, there will be some extremely useful before-and-after comparison information to show the difference between cooling something via the engine bay side-vents or via the front of the car.
 
On an unrelated note, if I do decide to make some changes, I may also change my intake manifold/plenum, which is something else that I maybe should have done the first time.

stuka
Thats pretty cool (pardon the pun) Rob, nothing like a scientific approach to determine whats best for your car. Once you have improved the system please update so we can see the level of improvement.

For sure!
 

stuka
Whats the plan for the manifold/plenum? Just be wary some of the aftermarket ones can be tricky to fit with the engine in the car and sidefeeds can result in some rearranging of other components in the engine bay too.

At this stage I'm thinking the RacerX plenum, perhaps still centre-feed so I don't have to make any major changes to my intake piping. I guess I would replace the TVIS with a phenolic spacer too.
If I decide to change the plenum and A2W system, I would get it all done at the same time. It would be nice if it can all be done with the engine in the car, but I'll have to wait and see.
 
If I do change the plenum, I also need to decide if I want to change the throttle body from my stock gen 2 one. According to an ongoing discussion on MR2OC, there are huge horsepower builds still running the stock throttle body. Also, increasing the throttle body diameter makes it harder to make mild throttle movements off idle (I don't know to what extent though).

Oh yeah I forgot to mention the KU engineering / JUN intake manifolds. I will probably choose between one of those or a RacerX intake manifold.

I guess I could also consider re-plenums, ie. retaining stock runners. This adds ATS racing into the mix, among others. Hmmm, too many choices.

Quaife review pls!! :D

I've been thinking a lot about how to modify my W2A IC and intake manifold setup, and I'm leaving this open to discussion.

These images (of my existing setup) show the physical locations of all the things that are most relevant:







Originally I was going to keep the heat exchanger in the right engine bay vent (and add a front mount heat exchanger of course, in series), and remove the heat exchanger on the top left of the engine bay, but I've been convinced by kameleon that there is no point keeping any heat exchangers in the engine bay. I was reluctant about undoing what has already been done, but I've almost accepted that I should only have a front mount heat exchanger.

Also, as mentioned previously, I want to upgrade to an aftermarket intake manifold/plenum.
The positions where my existing water hoses come out of the rear firewall from the W2A barrel (one behind the plenum with a 90 degree joiner, and another on the right of the plenum) would currently prevent me from using any of the bigger aftermarket plenums, due to lack of clearance. Given that I'm probably going to remove my W2A heat exchangers from the engine bay, I'm somewhat open to moving the water hoses so they come out of the firewall in different locations. I'd rather not, because I don't want to have to patch up heaps of holes in the firewall and make lots of new ones, but I won't rule it out.

Anyway, this is my latest idea:

- Move the W2A barrel upwards so it is just below where the 2 water hoses go through the rear firewall, and keep the hoses in the same locations in the firewall
- Keep the left/hot air pipe (from the turbo) coming out of the firewall in the same place, but just change the bend that goes into the barrel on the left
- Have a straight-runner (best for performance), right-side-feed plenum poking through the firewall where the barrel is at the moment, ie. directly below the proposed barrel location
- Completely remove the entire existing post-barrel piping from the right of the barrel, and cover up that hole in the firewall, leaving the top of the engine completely unobstructed
- Have a short U-bend from the right of the barrel directly into the side-feed throttle body below it in the boot (I need to consider that there would need to be plenty of flex in this bend)

The only thing I don’t like about this is that I would have a gaping hole in the boot for the plenum to poke through. Originally I was totally against anything like that, but maybe I could learn to accept it. I would try to engineer some way of reducing the chance of dirt or water from getting into the boot through the hole around the plenum/runners.
Besides, how awesome would it look having the barrel directly above the plenum in the boot, and having nothing on top of the engine.

I should also mention that I would rather not change the W2A barrel/IC itself, as that is one of the most expensive parts related to this situation, and it seems to be doing it's job quite well already (the heat exchangers are the problem). If I was going to change the barrel, now would be the time to do it, but I won't change it just for the sake of it.

I'm open to discussion and other ideas, mainly regarding the intake manifold/plenum, and how it would affect the locations where hoses and pipes go through the firewall.

kameleon
I like your idea.

I reckon with a straight-runner intake manifold, and significantly reduced intake temps, my power levels could quite easily end up near the 300rwkw mark.
The reduced intake temps would allow a combination of more boost, and (more importantly) more timing without knock.
An aftermarket plenum, especially with straight runners, can supposedly provide tens of kilowatts of additional power in the top end.
 

kameleon
Make a mucket for the plenum where it protrudes into the boot and you will stop dust etc getting into the boot.

mucket?

kameleon
Mucket is a flexible seal type arangement. Basically something that is sealing but can maintain that seal when the engine is moving etc.

OK yeah, that's the sort of thing I was thinking of doing, I've just never heard of the term 'mucket'.
It wouldn't be straight-forward to implement a flexible seal for the intake runners, but I would try to come up with something if I pursued my idea.