Intercooler/Heat Exchanger Efficiency

[turbo8765]

Originally Posted by gsrbri

What's interesting when contrasting the S63 TU system and the S55 system is: The V-8 certainly has more cooling surface area for reducing intake charge temps that the I-6 does

I haven't seen dimensions for the heat exchangers. Do you have this information?

[gsrbri]

Don't have the dimensions, but the M5/M6 use three front-mounted intercoolers vs. the M3/M4's two. Bigger engine, more power, more intake charge heat - right?

[turbo8765]

Originally Posted by gsrbri

Don't have the dimensions, but the M5/M6 use three front-mounted intercoolers vs. the M3/M4's two. Bigger engine, more power, more intake charge heat - right?

Displacement (bigger engine) doesn't affect IAT. More power also does not NECESSARILY equate to higher IAT.

IAT is dependent upon ambient temp, pressure ratio, compressor adiabatic efficiency, and intercooler efficiency... primarily.

[Maddict3]

Funny you mention that.

I ran about 30+ laps at SPA and did the same think you did and my intercooler was also very cool.

[sh55]

Originally Posted by gsrbri

Great diagram on page 87 (Page 93 in the Abobe reader) of the attached BMW Tech Guide document that was posted here a month or so back. Tried to copy/paste, but I'm definitely software challenged, so couldn't make it work.

You posted it before I could, I have read this document way to many times waiting for my car

The diagram on page 96 (102 in adobe reader) isolates the 4 liter charge air cooling system with 2 radiators. The larger low temp radiator sits in front of the engine radiator, so it is cooled by outside air before it passes through the engine radiator. The 2nd low temp radiator is on it's own in the passenger side (LHD) bumper opening.

Keep them temps low

[gsrbri]

Originally Posted by turbo8765

Displacement (bigger engine) doesn't affect IAT. More power also does not NECESSARILY equate to higher IAT.

IAT is dependent upon ambient temp, pressure ratio, compressor adiabatic efficiency, and intercooler efficiency... primarily.

Getting the engine IAT to ambient is the challenge and has everything to do with engine output, boost, and displacement. Cooling a 300 F intake charge down to 80 degrees requires significant thermal efficiency. A heavily boosted V-8 will develop more heat than the I6. That's just physics (unless the smaller engine is running much higher boost or more inefficient compressors). Otherwise, there would be the reverse intercooler set up on both cars.

[pkimM3r]

Originally Posted by tom @ eas

Same here, we on at almost every session at the Buttonwillow event in ~105F heat trying to see what would overheat first, while taking turns starting at water/oil temps on the Awron gauge.

Very happy. Cooling has MUCH improved on the S55 compared to S65.

huh? heat soak turbo vs s65 that didnt care what the temps were?

[TMR]

Originally Posted by pkimM3r

huh? heat soak turbo vs s65 that didnt care what the temps were?

The S65 was dog slow on hot day.