[drapzzy]

The title says all, just ordered it and was wondering if anyone has anything to say about it and if its better over stock, currently have a bm3 stage 2 ACN tune and want something that can keep the car colder

[gameson]

better than stock? of course, 100% better, but the consensus here said you should get the largest possible as there won't be any lag. if you have not install it, get the 6.5" competition, or better yet, get the race version

[drapzzy]

Originally Posted by gameson

consensus said you should get the largest possible as there won't be any lag. if you have not install it, get the 6.5" competition, or better yet, get the race version

already ordered but I'm going to do some logs on it anyways and see how it performs over stock but it does have a nice density core so I think it should at least be enough.

[gameson]

Originally Posted by drapzzy

already ordered but I'm going to do some logs on it anyways and see how it performs over stock but it does have a nice density core so I think it should at least be enough.

It will perform better 1000% over stock lol. No questions about that. No need to log to prove how it performs if you are comparing to stock.

However if you are comparing with other brand fmic in similar size capacity or bigger, then log is required to properly compare them.

If you already have stage 2 tune on the car, then you should stop driving the car until you get the fmic installed. To prevent overheating and blowing your engine.

Flash back to stock if you are driving it daily, btw with stage 2, you need to change the downpipe and charge pipe at the minimum. Have you done that?

[johnung]

Originally Posted by drapzzy

already ordered but I'm going to do some logs on it anyways and see how it performs over stock but it does have a nice density core so I think it should at least be enough.

You mentioned your tune, but what engine do you have? Please take 1st through 4th gear logs. Shut it down when you shift into 5th gear.

[drapzzy]

Originally Posted by johnung

You mentioned your tune, but what engine do you have? Please take 1st through 4th gear logs. Shut it down when you shift into 5th gear.

I have the lci n26 with timing chain fix (4 cyl)

[johnung]

Originally Posted by gameson

better than stock? of course, 100% better, but the consensus here said you should get the largest possible as there won't be any lag. if you have not install it, get the 6.5" competition, or better yet, get the race version

"Consensus"? 😀
We are a small group of opinionated guys arguing/discussing a subject, turbo lag, that can't easily be quantitatively evaluated.

I still stand by my two points:

1) Physics says that more volume in an Intercooler means more turbo lag is more likely.

2) I've actually observed friends with same car and tune, but with large Intercoolers, drive my car and say it's more responsive (less lag) than theirs.

I think we should all have some beers! 😀

[sqwinny]

I still say the 5" intercooler is best for stock turbo and OTS tunes. With the 6.5 there was a small amount of lag to pressurize the intercooler (ATM/CSF) but going custom tune fixed the lag completely

[johnung]

Originally Posted by sqwinny

I still say the 5" intercooler is best for stock turbo and OTS tunes. With the 6.5 there was a small amount of lag to pressurize the intercooler (ATM/CSF) but going custom tune fixed the lag completely

Can't imagine how a custom tune could reduce lag?

[drapzzy]

Originally Posted by johnung

"Consensus"? 😀
We are a small group of opinionated guys arguing/discussing a subject, turbo lag, that can't easily be quantitatively evaluated.

I still stand by my two points:

1) Physics says that more volume in an Intercooler means more turbo lag is more likely.

2) I've actually observed friends with same car and tune, but with large Intercoolers, drive my car and say it's more responsive (less lag) than theirs.

I think we should all have some beers! 😀

I also have a charge pipe so if there was any lag this would help reduce it

[gameson]

Originally Posted by johnung

2) I've actually observed friends with same car and tune, but with large Intercoolers, drive my car and say it's more responsive (less lag) than theirs.

every car has different characterics, just curious, what cars are you comparing together in?

[johnung]

Originally Posted by gameson

every car has different characterics, just curious, what cars are you comparing together in?

F30 335i N55
It actually made for a pretty good scientific experiment because at the time our engine mods, tune, etc were all identical except for our intercooler upgrades. Theirs were much larger. We weren't trying to do an experiment. It was an observation that we all had about mine seeming more responsive, so we tried to figure out what may have caused it.

Now with my fueling mods my engine power is higher so my upgraded intercooler no longer has the capacity to cool fast enough. I'm concerned about just automatically choosing a giant intercooler and potentially adding turbo lag. So I'm trying to see if a mid-size intercooler will cool enough for my current engine power.

It just makes sense to me that if I'm trying to cool an engine in the 450-500whp range, that a giant intercooler that can handle 600-700whp may be overkill, and could potentially cause increased turbo lag.

Hey, my logic makes sense to me. I could be wrong but there isn't an easy way to design a quantitative experiment. I figure that if I install a midsize intercooler and it handles IATs to my satisfaction, that I'm probably minimizing turbo lag too. If it doesn't handle IATs to my liking then I won't have much choice but to install a large intercooler. We'll see. This is what makes modding fun! 😀

[sqwinny]

Originally Posted by johnung

Can't imagine how a custom tune could reduce lag?

It was weird. First install with the ATM/CSF intercooler there was a slight hesitation compared to the 5". Now it's gone with upgraded turbo + custom tune. Could have been install error, could have been a small leak with the turbo to intercooler pipe, who knows. All I know is throttle response was back after big turbo install + custom tune.

[gameson]

what fueling mods do you have now? thanks.

Originally Posted by johnung

F30 335i N55
It actually made for a pretty good scientific experiment because at the time our engine mods, tune, etc were all identical except for our intercooler upgrades. Theirs were much larger. We weren't trying to do an experiment. It was an observation that we all had about mine seeming more responsive, so we tried to figure out what may have caused it.

Now with my fueling mods my engine power is higher so my upgraded intercooler no longer has the capacity to cool fast enough. I'm concerned about just automatically choosing a giant intercooler and potentially adding turbo lag. So I'm trying to see if a mid-size intercooler will cool enough for my current engine power.

It just makes sense to me that if I'm trying to cool an engine in the 450-500whp range, that a giant intercooler that can handle 600-700whp may be overkill, and could potentially cause increased turbo lag.

Hey, my logic makes sense to me. I could be wrong but there isn't an easy way to design a quantitative experiment. I figure that if I install a midsize intercooler and it handles IATs to my satisfaction, that I'm probably minimizing turbo lag too. If it doesn't handle IATs to my liking then I won't have much choice but to install a large intercooler. We'll see. This is what makes modding fun! 😀

[johnung]

Originally Posted by drapzzy

I also have a charge pipe so if there was any lag this would help reduce it

I'm not sure that I follow how an aftermarket aluminum charge pipe would reduce lag?

The charge intake system has three main components that are subject to modding:
1) The Turbo to Intercooler (TIC) Pipe, also called the Boost Pipe.
2) The Front Mounted Air to Air Intercooler (FMIC)
3) Charge Pipe from the intercooler to the throttle body on the engine.

Aftermarket TIC and CP's are roughly the same size and shape as their stock parts. In fact if they are different at all they tend to be slightly larger. More volume would contribute negatively to turbo lag.

My Evolution Racewerks charge pipe is noticeably larger. The smooth straight walls are seen as an advantage to reduce air turbulence so that might help flow while the extra volume to fill could be seen as contributing to lag when trying to build boost.

The TIC pipe is much shorter than the CP so an aftermarket TIC would have less impact on lag.

So the aftermarket Intercooler has by far the biggest potential impact on lag. There are several factors but if you just look at volume for example. The stock intercooler has a core volume of about 450 cubic inches. A big race intercooler could be 1,450 cubic inches, over 200% larger.

So of the three components upgrading one or both of the two pipes isn't likely to effect lag. It's the intercooler that does the cooling and would have the most effect on turbo lag.

[johnung]

Originally Posted by sqwinny

It was weird. First install with the ATM/CSF intercooler there was a slight hesitation compared to the 5". Now it's gone with upgraded turbo + custom tune. Could have been install error, could have been a small leak with the turbo to intercooler pipe, who knows. All I know is throttle response was back after big turbo install + custom tune.

Ah, the key phrase that you said was "throttle response". Our gas pedals are drive by wire. So a sensor on the pedal tells the car's computer how far and how fast our foot presses the pedal. BMW programs the pedal to be mild initially. It's purposely not sensitive so people don't touch the gas pedal and go flying into the car in front of them.

The pedal programming can get sophisticated. So driving slowly through a parking lot provides a less responsive pedal while driving at 50mph has a more responsive pedal. Sport Mode would have a more responsive pedal than Comfort Mode.

Engine tuners whether they are custom or OTS like Bootmod3 or MHD usually tune the gas pedal for specific response parameters.

So what you are interpreting as less engine turbo lag is probably the engine tune also having a different gas pedal response profile.

[johnung]

Originally Posted by gameson

what fueling mods do you have now? thanks.

N55 EWG with stock turbo
Dorch Stage2 HPFP
Precision Raceworks Stage 2.5 v2 LPFP
Precision Raceworks Fuel Line Kit
Zeitronix CANBus ethanol sensor with dashboard gauge
Bootmod3 FlexFuel MultiMap tune

[sqwinny]

Originally Posted by johnung

Ah, the key phrase that you said was "throttle response". Our gas pedals are drive by wire. So a sensor on the pedal tells the car's computer how far and how fast our foot presses the pedal. BMW programs the pedal to be mild initially. It's purposely not sensitive so people don't touch the gas pedal and go flying into the car in front of them.

The pedal programming can get sophisticated. So driving slowly through a parking lot provides a less responsive pedal while driving at 50mph has a more responsive pedal. Sport Mode would have a more responsive pedal than Comfort Mode.

Engine tuners whether they are custom or OTS like Bootmod3 or MHD usually tune the gas pedal for specific response parameters.

So what you are interpreting as less engine turbo lag is probably the engine tune also having a different gas pedal response profile.

Perhaps. However on the stock tune you could give it 100% throttle input and there would be a half second delay until boost was made and the car would go forward. This still happens with the big turbo, but the stock turbo and the 5" g plus intercooler, car was as responsive if not more than the stock one. My comments are referring to the 5" g plus, not the factory intercooler.

[johnung]

Originally Posted by sqwinny

Perhaps. However on the stock tune you could give it 100% throttle input and there would be a half second delay until boost was made and the car would go forward. This still happens with the big turbo, but the stock turbo and the 5" g plus intercooler, car was as responsive if not more than the stock one. My comments are referring to the 5" g plus, not the factory intercooler.

You may be right. I don't know enough about the nitty gritty details about pedal tuning. It wouldn't surprise me if BMW still has a slight delay programmed in if a driver puts the pedal to the floor. Perhaps engine tuners remove that delay in their tunes.

[drapzzy]

Originally Posted by sqwinny

Perhaps. However on the stock tune you could give it 100% throttle input and there would be a half second delay until boost was made and the car would go forward. This still happens with the big turbo, but the stock turbo and the 5" g plus intercooler, car was as responsive if not more than the stock one. My comments are referring to the 5" g plus, not the factory intercooler.

I think 5" is the best solution if you don't want to increase lag and we also arent making crazy power on our 328i but we are making big boost, the MAD has very similar specs to the G plus one so the only think i can say is i will let you know once installed

[mike@x-ph.com]

Originally Posted by drapzzy

I think 5" is the best solution if you don't want to increase lag and we also arent making crazy power on our 328i but we are making big boost, the MAD has very similar specs to the G plus one so the only think i can say is i will let you know once installed

Let us know how it goes

[LiamLikesFruit]

Originally Posted by johnung

I'm not sure that I follow how an aftermarket aluminum charge pipe would reduce lag?

The charge intake system has three main components that are subject to modding:
1) The Turbo to Intercooler (TIC) Pipe, also called the Boost Pipe.
2) The Front Mounted Air to Air Intercooler (FMIC)
3) Charge Pipe from the intercooler to the throttle body on the engine.

Aftermarket TIC and CP's are roughly the same size and shape as their stock parts. In fact if they are different at all they tend to be slightly larger. More volume would contribute negatively to turbo lag.

My Evolution Racewerks charge pipe is noticeably larger. The smooth straight walls are seen as an advantage to reduce air turbulence so that might help flow while the extra volume to fill could be seen as contributing to lag when trying to build boost.

The TIC pipe is much shorter than the CP so an aftermarket TIC would have less impact on lag.

So the aftermarket Intercooler has by far the biggest potential impact on lag. There are several factors but if you just look at volume for example. The stock intercooler has a core volume of about 450 cubic inches. A big race intercooler could be 1,450 cubic inches, over 200% larger.

So of the three components upgrading one or both of the two pipes isn't likely to effect lag. It's the intercooler that does the cooling and would have the most effect on turbo lag.

Nailed it! When it comes to volume, I was always told to upgrade to "bigger" needs to be dealt with by more volume to keep pressure up so you dont feel that minute lag. Referring to charge pipe, I was always told it's just so you can replace that plastic POS.