5" versus 7" FMIC

Team503 · 04-06-2015, 10:40 AM

I plan to stay on stock turbos for the foreseeable future - will I see a lag difference between the 5" stepped and 7" FMIC? Is there a gain to be had, powerwise, with the larger intercooler?

335NJ · 04-06-2015, 10:47 AM

I haven't compared them personally so I'm not sure about the potential lag, however the 7" will cool better than the 5" stepped. Although anything bigger than stock is a huge upgrade.

Jeff@TopGearSolutions · 04-06-2015, 10:53 AM

Both will make the same power but a 7" will have less tendency to heat soak.

The pressure loss and lag is negligible in my opinion.

Team503 · 04-06-2015, 10:59 AM

Quote:

Originally Posted by Jeff@TopGearSolutions

Both will make the same power but a 7" will have less tendency to heat soak.

The pressure loss and lag is negligible in my opinion.

That's what I was looking for. Thanks Jeff!

mike@x-ph.com · 04-06-2015, 11:07 AM

Agree with Jeff

ajsalida · 04-06-2015, 11:22 AM

Same, agree with Jeff and also direct personal experience to back it up. Went from 5" non-stepped to 7". No lag difference and much better heat soak properties.

No extra power either except when things had gotten too hot previously and the 7" cured that. Was getting timing pulls with the 5" and under similar conditions none with 7". Stepped 5" may be closer to 7" as far as heat soak goes, and since no lag diff between non stepped 5" vs 7" I doubt any with stepped.

007_e350 · 04-06-2015, 01:11 PM

JB4 on map5 automatically compensates for the lag, no issues ... Cobb has a setting for it I dont remember what it was called now

Jeff@TopGearSolutions · 04-06-2015, 01:44 PM

Quote:

Originally Posted by ajsalida

Same, agree with Jeff and also direct personal experience to back it up. Went from 5" non-stepped to 7". No lag difference and much better heat soak properties.

No extra power either except when things had gotten too hot previously and the 7" cured that. Was getting timing pulls with the 5" and under similar conditions none with 7". Stepped 5" may be closer to 7" as far as heat soak goes, and since no lag diff between non stepped 5" vs 7" I doubt any with stepped.

Fundguy1 · 04-06-2015, 02:10 PM

Haven't noticed any lag differences with mine either. PITA to cut the plastic but well worth it once it's in.

Nguyenhu0106 · 04-06-2015, 03:45 PM

hi,
I personally have a 7 inch.. as stated above this mod won't make more power but what it will do is keep you from losing HP in the upper range of the RPM.
you do not notice it as much with a stock tune but it becomes very apparent when you up the boost. the drop in power around 6500-7000 to redline.

if your tuned this is one of the must mods in my opinion.

hung

335NJ · 04-06-2015, 05:00 PM

As far as "more power" goes, cooler air carries more oxygen to go boom. Which equals "power". Cooler temps will always be best.

ajsalida · 04-06-2015, 05:37 PM

Quote:

Originally Posted by 335NJ

As far as "more power" goes, cooler air carries more oxygen to go boom. Which equals "power". Cooler temps will always be best.

Of course. The point is a 5" will cool down to the near-ambient limit as well as a 7" up to a point. The 7" adds nothing. Then it starts getting hotter after multiple WOT pulls or you get a more aggressive set of mods and run higher boost, only then will the benefits of a 7" start to kick in.

Tiago@VRSF · 04-06-2015, 06:47 PM

There's a lot of good info in this thread but I'll just add that a 7" intercooler will make more power up top on a 2-4 gear pull in comparison to a 5" due to it's ability to keep temps as close to ambient as possible (assuming the fin pack design is the same).

You may not notice the difference on a third gear pull but you'll definitely notice on a multiple gear pull or a back to back pull.

Petrolhead3010 · 04-08-2015, 11:59 AM

I've had the 6" AA IC for about 6 months now. I love it! No heatsoak issues so far, & didn't have to cut anything for the install.

Fundguy1 · 04-08-2015, 01:05 PM

Yes and being in florida for me the extra heat disappation helps a lot.

Mike@N54Tuning.com · 04-08-2015, 02:10 PM

Quote:

Originally Posted by Fundguy1

Yes and being in florida for me the extra heat disappation helps a lot.

You should see no lag with wither sized FMIC. As for power gains a larger unit or a more efficient core will give you upper RPM and higher gear / load gains versus a smaller unit, and most importantly won't heat soak as fast as a smaller unit. So if you are driving the car hard for an extended amount of time a larger / more efficient unit is beneficial.

Mike

04-06-2015, 10:40 AM	#1
Team503 Nerd 125 Rep 437 Posts Drives: 2009 335i Sport/Auto/Luxury Join Date: Jul 2013 Location: Dublin iTrader: (5)	5" versus 7" FMIC - Lag issues? I plan to stay on stock turbos for the foreseeable future - will I see a lag difference between the 5" stepped and 7" FMIC? Is there a gain to be had, powerwise, with the larger intercooler? __________________ 2009 E92 335i Sport 6AT - Finished, sold Transport for Ireland - LEAP Pass with TFI smartapp because cars are stupid expensive in Ireland
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04-06-2015, 10:47 AM	#2
335NJ Colonel 533 Rep 2,872 Posts Drives: 2008 335i 6MT E90 Join Date: Feb 2014 Location: NJ/Philadelphia Suburbs iTrader: (1)	I haven't compared them personally so I'm not sure about the potential lag, however the 7" will cool better than the 5" stepped. Although anything bigger than stock is a huge upgrade.
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04-06-2015, 10:53 AM	#3
Jeff@TopGearSolutions 3441 Rep 79,211 Posts Drives: C6 Z06, 09 335i, 10 335xi Join Date: Dec 2008 Location: www.TopGearSolutions.com iTrader: (37)	Both will make the same power but a 7" will have less tendency to heat soak. The pressure loss and lag is negligible in my opinion.
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04-06-2015, 11:07 AM	#5
mike@x-ph.com BimmerPost Supporting Vendor 24165 Rep 190,725 Posts Drives: 07-335/12-328/18-M4/21-M4CP Join Date: Sep 2013 Location: Las Vegas iTrader: (23)	Agree with Jeff __________________ Check out our current sale by clicking on this link! https://x-ph.com/sale/ Phone number 702-494-9435
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04-06-2015, 11:22 AM	#6
ajsalida Colonel 226 Rep 2,387 Posts Drives: 95 M3, 02 R1150GSA, 09 335xi Join Date: Aug 2010 Location: SW USA iTrader: (2)	Same, agree with Jeff and also direct personal experience to back it up. Went from 5" non-stepped to 7". No lag difference and much better heat soak properties. No extra power either except when things had gotten too hot previously and the 7" cured that. Was getting timing pulls with the 5" and under similar conditions none with 7". Stepped 5" may be closer to 7" as far as heat soak goes, and since no lag diff between non stepped 5" vs 7" I doubt any with stepped.
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04-06-2015, 01:11 PM	#7
007_e350 Lieutenant Colonel 217 Rep 1,909 Posts Drives: 335i 2008 MHD'd / x5d E70 Join Date: May 2013 Location: left lane iTrader: (3)	JB4 on map5 automatically compensates for the lag, no issues ... Cobb has a setting for it I dont remember what it was called now __________________ Mods: 7" VRSF FMIC, Forge DVs, RB PCV, BMS Oil Cooler, VRSF DPs, MHD, JB4g5, OFT DIYs: Walnut blasting : Trans Oil at 45k, w Filter at 65k : Diff Oil Flush @ 45k : WP&TS @ 69k : Alternator @ 79k --- E70d Alphabet Soup del 44.4k : JR Stg2.25 tune : Buzzken Catted Exhaust : Trans fluid drain/ fill (3 Qrts), both Diffs fluids flushed Wheels: Style 95s on PSSs (Sold): AG 359s on S04s : 162s on Blizzaks : Rohana RF1 Matt black
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04-06-2015, 02:10 PM	#9
Fundguy1 Major General 2032 Rep 8,339 Posts Drives: 335 e93 Join Date: Aug 2014 Location: Orlando, fl iTrader: (0)	Haven't noticed any lag differences with mine either. PITA to cut the plastic but well worth it once it's in. __________________ '08 e93 AW 335i 6MT,Vargas Stg 2+ 20T clipped,VRSF catless dps & 7"FMIC,ER chargepipe&Tial, MMP inlets&outlets,Motiv Stg 2 fuel rail&dual disc clutch/fly, JB4G5,MHD w/Motiv tune,Fuel-it Stg 3 LPFP,Wavetrac LSD w/lockdown, KwV2,M3(Strut brace,frt control arms,steering wheel)AKE blk sub bush,re11 245/305,19x8.5et30&19x11et43,SmartTop,RE trans mounts,Msport rear bump & skirts,15%tint,ZSP knob,Stoptech rotors,241k miles
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04-06-2015, 03:45 PM	#10
Nguyenhu0106 Private First Class 27 Rep 199 Posts Drives: 2007 335i Join Date: Dec 2012 Location: Chicago, il iTrader: (1)	hi, I personally have a 7 inch.. as stated above this mod won't make more power but what it will do is keep you from losing HP in the upper range of the RPM. you do not notice it as much with a stock tune but it becomes very apparent when you up the boost. the drop in power around 6500-7000 to redline. if your tuned this is one of the must mods in my opinion. hung
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04-06-2015, 05:00 PM	#11
335NJ Colonel 533 Rep 2,872 Posts Drives: 2008 335i 6MT E90 Join Date: Feb 2014 Location: NJ/Philadelphia Suburbs iTrader: (1)	As far as "more power" goes, cooler air carries more oxygen to go boom. Which equals "power". Cooler temps will always be best.
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04-06-2015, 06:47 PM	#13
Tiago@VRSF 2095 Rep 43,350 Posts Drives: F90 M5 Join Date: Dec 2007 Location: Doral, FL iTrader: (99) Garage List 2014 F30 328xi [0.00] 2015 F82 BMW M4 [0.00] 2013 Ducati 1199 Pa ... [0.00] 2008 BMW 335i [0.00]	There's a lot of good info in this thread but I'll just add that a 7" intercooler will make more power up top on a 2-4 gear pull in comparison to a 5" due to it's ability to keep temps as close to ambient as possible (assuming the fin pack design is the same). You may not notice the difference on a third gear pull but you'll definitely notice on a multiple gear pull or a back to back pull.
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04-08-2015, 11:59 AM	#14
Petrolhead3010 Second Lieutenant 52 Rep 252 Posts Drives: 2021 BMW X3 M40i Join Date: Aug 2014 Location: Marysville iTrader: (0)	I've had the 6" AA IC for about 6 months now. I love it! No heatsoak issues so far, & didn't have to cut anything for the install.
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04-08-2015, 01:05 PM	#15
Fundguy1 Major General 2032 Rep 8,339 Posts Drives: 335 e93 Join Date: Aug 2014 Location: Orlando, fl iTrader: (0)	Yes and being in florida for me the extra heat disappation helps a lot.
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