[johnung]

Hoping some IAT guys will will take a look at my logs below and provide their opinions on whether the current upgraded FMIC is cooling adequately or if it's being overwhelmed? I'm not intending to upgrade the turbo. I don't want to spend money on a larger FMIC with potentially more turbo lag if the current FMIC is doing the cooling job right now. Any analysis/ opinions are appreciated. Thanks!

N55 EWG with stock turbo
BootMod3 FlexFuel MultiMap tune with E50 fuel in the tank. WOT logs taken from 1st->4th gears

https://www.bootmod3.net/log?id=6186...90c6283fe0a8e4

https://www.bootmod3.net/log?id=6186...729b69de5fb411

https://www.bootmod3.net/log?id=6186...90c6283fe0a8f0

[AmuroRay]

Ambient temps? No matter how you slice it, that IAT control is not good +10F in 3rd gear, +14F in 4th gear.
It’s terrible and the only way this is serviceable will be in lower ambient temps (probably 50s or low 60s where you are)

Once it’s around 70s or 80s, this IC will be useless.

[johnung]

Originally Posted by AmuroRay

Ambient temps? No matter how you slice it, that IAT control is not good +10F in 3rd gear, +14F in 4th gear.
It’s terrible and the only way this is serviceable will be in lower ambient temps (probably 50s or low 60s where you are)

Once it’s around 70s or 80s, this IC will be useless.

Thanks for responding. I understand what you are saying about looking at difference between ambient and IATs to judge cooling effectiveness of the FMIC. Curious at what actual IAT temperatures in logs you have seen symptoms of Heat Soak begin?

[AmuroRay]

Heat soak? I haven’t seen anyone really mention that on this platform. I’ve seen in mentioned on the E series, but that was issues with frontal area airflow.

[johnung]

Originally Posted by AmuroRay

Heat soak? I haven’t seen anyone really mention that on this platform. I’ve seen in mentioned on the E series, but that was issues with frontal area airflow.

Heat Soak is felt by the driver as engine sluggishness/loss of power leading to potential Limp Mode. It's the engine protecting itself if IATs are too high. My understanding is that it's seen in logs as excess timing adjustments, throttle reduction and ultimately, limp mode.

I'm curious what the actual IAT temperature is that begins that process.

Before I upgraded my FMIC I could get the engine to begin heat soaking especially on a hot summer day by running multiple WOT runs in rapid succession with little recovery time. On subsequent runs the engine would get noticeably sluggish. I wish I had collected logs at the time to have an accurate numerical description.

[thejeremyman9]

Originally Posted by johnung

Heat Soak is felt by the driver as engine sluggishness/loss of power leading to potential Limp Mode. It's the engine protecting itself if IATs are too high. My understanding is that it's seen in logs as excess timing adjustments, throttle reduction and ultimately, limp mode.

I'm curious what the actual IAT temperature is that begins that process.

Before I upgraded my FMIC I could get the engine to begin heat soaking especially on a hot summer day by running multiple WOT runs in rapid succession with little recovery time. On subsequent runs the engine would get noticeably sluggish. I wish I had collected logs at the time to have an accurate numerical description.

AFAIK its not a bright line threshold. So its not like, >120F the DME automatically starts pulling timing. Its going to depend on fuel quality, knock sensitivity, etc. The bottom line is that higher IATs will inherently make less power due to lower air density, and can lead to knock/timing corrections which will further reduce power.

You log shows basically 77F to 107F in the 1-4 gear pull. So 30F rise. If its 100 degrees outside to begin with you are probably going to be over 140F IATs from one multi gear pull like that. So yeah, i would say IC is undersized.

[AmuroRay]

Originally Posted by thejeremyman9

AFAIK its not a bright line threshold. So its not like, >120F the DME automatically starts pulling timing. Its going to depend on fuel quality, knock sensitivity, etc. The bottom line is that higher IATs will inherently make less power due to lower air density, and can lead to knock/timing corrections which will further reduce power.

You log shows basically 77F to 107F in the 1-4 gear pull. So 30F rise. If its 100 degrees outside to begin with you are probably going to be over 140F IATs from one multi gear pull like that. So yeah, i would say IC is undersized.

This also doesn’t factor in his baseline IAT over ambient. A good core can baseline at 10F over ambient, I’ve seen some brands at 20F over ambient, and then there is a rise in IATs from there, which is why I asked what the ambient temperatures were where he is at. He could be looking at 50F over ambient which I find unacceptable, but to each their own.

[AmuroRay]

Originally Posted by johnung

Heat Soak is felt by the driver as engine sluggishness/loss of power leading to potential Limp Mode. It's the engine protecting itself if IATs are too high. My understanding is that it's seen in logs as excess timing adjustments, throttle reduction and ultimately, limp mode.

I'm curious what the actual IAT temperature is that begins that process.

Before I upgraded my FMIC I could get the engine to begin heat soaking especially on a hot summer day by running multiple WOT runs in rapid succession with little recovery time. On subsequent runs the engine would get noticeably sluggish. I wish I had collected logs at the time to have an accurate numerical description.

Oh, if you’re asking when Timing pull occurs, as Jeremy stated, it’s not a set number - it depends on a lot of factors, but I’ve seen 109F mentioned.

[n55david]

yes, time to upgrade!

[ZM2]

From my logs timing starts getting pulled with IATs @ 105-110F with 93 octane, ~145F with E50.

Those high IATs are what made me switch from the Evo2 to the Evo3. Even if timing isn’t getting pulled with a high ethanol mix, you’re just pumping hot air into the engine which will push your coolant & oil temps high. But, your rise in each gear is really highlighting the issue.

If I do a single gear pull my IATs are 10-12F above ambient with a cooled off IC. If it’s a hot day and I do back to back multigear pulls with hard braking in between, I max out at ~25F above ambient. Not too bad I reckon since I’m probably pushing ~550 engine hp.

[johnung]

Originally Posted by ZM2

From my logs timing starts getting pulled with IATs @ 105-110F with 93 octane, ~145F with E50.

Those high IATs are what made me switch from the Evo2 to the Evo3. Even if timing isn't getting pulled with a high ethanol mix, you're just pumping hot air into the engine which will push your coolant & oil temps high. But, your rise in each gear is really highlighting the issue.

If I do a single gear pull my IATs are 10-12F above ambient with a cooled off IC. If it's a hot day and I do back to back multigear pulls with hard braking in between, I max out at ~25F above ambient. Not too bad I reckon since I'm probably pushing ~550 engine hp.

"From my logs timing starts getting pulled with IATs @ 105-110F with 93 octane, ~145F with E50."

So the higher ethanol content in the fuel drives the start of Heat Soak timing adjustments upward by 35F-40F? I would not have guessed that.

I recall that the EVO3 is much larger than the EVO2. (I have an EVO1 now) With the larger FMIC volume, did you notice an increase in turbo lag?

[ZM2]

Originally Posted by johnung

"From my logs timing starts getting pulled with IATs @ 105-110F with 93 octane, ~145F with E50."

So the higher ethanol content in the fuel drives the start of Heat Soak timing adjustments upward by 35F-40F? I would not have guessed that.

I recall that the EVO3 is much larger than the EVO2. (I have an EVO1 now) With the larger FMIC volume, did you notice an increase in turbo lag?

Yeah, doesn’t matter if it’s race gas or ethanol, higher octane prevents pre-detonation and will allow higher IATs before timing gets pulled. Very handy for summer track days.

No lag at all. In fact response got better, and is backed up Wagner’s pressure drop charts comparing the Evo2 & Evo3. The Evo3 trades density for frontal area and volume to keep low to no lag while keeping IATs in check. Their larger custom inlet/outlet diameters and piping also helps.

Altho, if you’re not doing summer track days, I think you’re probably fine with something like the do88 IC. Just stay away from the Evo2.

[johnung]

Originally Posted by ZM2

Yeah, doesn't matter if it's race gas or ethanol, higher octane prevents pre-detonation and will allow higher IATs before timing gets pulled. Very handy for summer track days.

No lag at all. In fact response got better, and is backed up Wagner's pressure drop charts comparing the Evo2 & Evo3. The Evo3 trades density for frontal area and volume to keep no lag low to none while keeping IATs in check. Their larger custom inlet/outlet diameters and piping also helps.

Altho, if you're not doing summer track days, I think you're probably fine with something like the do88 IC.

What is the do88 IC? I had been considering upgrading my EVO1 to the EVO2. Just heard good things about VRSF Race IC too.

I just read the specs on the Wagner EVO3 and it says that it isn't compatible with my XDrive model.

I have an absolute hatred for turbo lag so I want to make sure I handle IATs from the horsepower increase without introducing lag.

[AmuroRay]

Just do the VRSF competition if you’re open to VRSF. It’s ridiculous inexpensive for what it is, and will outcool anything in that size range, including the DO88. Which is otherwise a good option.

For what it’s worth, you’re likely not going to get lag on a race core on your set up. I have a VRSF Race sitting here, and the internal core is less dense then the external, and I believe @thejeremyman9 can confirm is the same density as their 5” core.

That means in terms of airflow, the Race core just offers more volume, which obviously needed on cars running more boost than stock. It’s an inch and a half thicker and about 3” taller than a standard 5” core. So if anything, the added volume is actually decreasing restriction. I’m also not convinced it’s too big for a 3 liter 400whp 6cyl engine - maybe on a 328i it would be an issue.

This may explain why the larger Evo 3 has less pressure drop than the Evo 2, and the Evo 2 less pressure drop than stock. And I’m pretty sure the Evo 3 is the larger internal volume of any IC on this platform

These cars are likely starving for more flow

[AmuroRay]

The Wagner Evo 2 is just not a good intercooler. People like it because if it’s light weight, has a good name, and has better cooling than stock.

The truth is that it’s literally amalgamation of all the worst IC features in one package.

It’s got great throttle response because the internal core has less surface area, so you would think there is less restriction. Honestly, this ‘benefit’ amounts to 1whp on a FBO car over another IC, and absolutely terrible heat transfer.

It won’t be able to cut heat down as fast as other intercoolers, and that ‘great throttle response’ is available on basically every other intercooler with 2 exceptions maybe.

Then it’s light weight (which is only 3-7lbs compared to other cores) means that it has less thermal capacity and will overheat quicker.

So with all of this you have an intercooler that gets hot fast, and can’t shed heat fast enough.

Did I mention it was expensive too?

[thejeremyman9]

I went from the VRSF 5'' to the VRSF race. They lowered their race price to compete with the other new race ICs on the market. Frankly its incredible value for what you get...

Here's a 0-150 mph pull with the race. IATs end where they started... That's basically 22 seconds of WOT

https://datazap.me/u/thejeremyman9/d...0&data=4-10-17

[gameson]

how about CSF FMIC? good FMIC?

If i get a big FMIC like VRSF competition (not performance) but with only stock turbo and bm3 stage 2 along with charge pipe changed and downpipe changed, would i still get turbo lag?

[ZM2]

Originally Posted by thejeremyman9

I went from the VRSF 5'' to the VRSF race. They lowered their race price to compete with the other new race ICs on the market. Frankly its incredible value for what you get...

Here's a 0-150 mph pull with the race. IATs end where they started... That's basically 22 seconds of WOT

https://datazap.me/u/thejeremyman9/d...0&data=4-10-17

Nice, that’s similar to how my Evo3 behaves, IAT drop in gears 1-3, flat in 4, few degrees higher in 5 & 6.

I think you’re pushing ~400whp? Any idea what ambient was that day?

[Logicoeur]

Originally Posted by gameson

how about CSF FMIC? good FMIC?

If i get a big FMIC like VRSF competition (not performance) but with only stock turbo and bm3 stage 2 along with charge pipe changed and downpipe changed, would i still get turbo lag?

Honestly can't feel any when driving in sport, and I have a PWG. But it's definitely there in comfort.

[AmuroRay]

Originally Posted by gameson

how about CSF FMIC? good FMIC?

If i get a big FMIC like VRSF competition (not performance) but with only stock turbo and bm3 stage 2 along with charge pipe changed and downpipe changed, would i still get turbo lag?

The CSF is a 5.5” (depth) core and the VRSF competition is 6.5”
The CSF is 26lbs and the VRSF is 27lbs
The CSF has 15-16 fins per in on the exterior core the VRSF is 18 fin per inch
The CSF is $600 and the VRSF $420
Both should fit with no issues

You will not get turbo lag with the VRSF, as confirmed by many members here including LYTSOUT

https://f30.bimmerpost.com/forums/sh....php?t=1752195

VRSF’s qc can leave some to be be desired, but the performance does not.

[AmuroRay]

Originally Posted by Logicoeur

Honestly can't feel any when driving in sport, and I have a PWG. But it's definitely there in comfort.

Do you have changed throttle settings in sport?

[Logicoeur]

Originally Posted by AmuroRay

Do you have changed throttle settings in sport?

No, with mhd the option to flash "linear throttle" is not enabled. It should be same as stock