![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
BMW Garage | BMW Meets | Register | Today's Posts | Search |
![]() |
![]() ![]() |
BMW 3-Series (E90 E92) Forum
>
AFE Header Review. AFE high flow Cat Headers
![]() |
![]() |
04-25-2015, 01:53 PM | #23 |
Lieutenant Colonel
![]() ![]() 187
Rep 1,677
Posts |
I'm absolutely insane for getting into this discussion, but...I need a distraction today (it's raining, my tune is in
![]() ![]() First of all, let me get this straight - our choices of combinations when it comes to headers are: 1) Catless headers (e.g. AA), retaining the secondaries 2) Catless headers, removing the secondaries 3) Catted headers (e.g. AFE), retaining the secondaries 4) Catted headers, removing the secondaries. Not to jack the thread, but here are some questions (say in a car with 3 stage manifold conversion, Euro airbox, PE and AA tune): a) Clearly, #2 would yield the most power, right? But by how much over #s 1, 3 and 4? b) How much less power than the others would you get if you chose #3? In other words, is this a horrible choice if you're looking for some noticeable gains? c) If you have the PE and you're already concerned about the sound it makes, should any of these even be considered without plans to modify the PE, such as put in a resonator (e.g. Vibrant) or a small race muffler (e.g. Borla) where the straight midpipe is? d) If smell is a concern (e.g. you have a convertible), is #1 still an option or is #3 really the only choice? Thanks! Talk amongst yourselves.
__________________
![]() ![]() "O thou afflicted, tossed with tempest, and not comforted, behold, I will lay thy stones with fair colours, and lay thy foundations with sapphires." (Isaiah 54:11) |
Appreciate
0
|
04-25-2015, 02:35 PM | #24 | |
Brigadier General
![]() ![]() 298
Rep 4,040
Posts
Drives: 130i coupé ;)
Join Date: Nov 2011
Location: Bimmerpost
|
Quote:
b) based on my feel for these: up to 10 whp less than #1 Catless header + Secondary Catss. This is a main catalyc so its more restrictive or in a bad position. If the dyno surprises us and shows a power curve and top numbers similar to Catless + secondary cat then these are a great idea... c,d I cant say But I think question that needs to be asked is. For maximum power where should the Catalycs be: in the midpipe or on the exhaust manifold
__________________
128i Sport 6MT converted to Euro 130i spec, 3.73 diff, tuned by evolve ~220 whp 207 wtq(ft-lb) SAE
In-progress: //M front arm, M3 rack, e36M lip Wishlist: Coils, n55 mnts, headers, LSD, e60 finn diff ![]() "The 1-series is the last car that BMW engineered before the Germans, as a car-making culture, fell out of love with driving." - R&T 2013 135is |
|
Appreciate
0
|
04-25-2015, 02:53 PM | #25 |
Member
![]() 30
Rep 115
Posts
Drives: Metallic Black 2006 325i
Join Date: Sep 2009
Location: San Francisco
|
max power would be towards the exit, but then renders the cats pointless and might as well go catless.
__________________
Fly the BMW.
|
Appreciate
0
|
04-25-2015, 03:37 PM | #26 |
Major General
![]() ![]() ![]() 3966
Rep 7,215
Posts |
Actually, what matters more is in the primaries and in the merge. With the cat located right at the merge, there's definitely a loss of scavenging effect (although less than the stock manifold design). The secondary cat would create some back pressure, assuming it's really a restriction - but the scavenging effect of the AA headers will be better regardless of the secondary cat.
Now if you swapped the 2nd cats for a y merge, then you would be on to something. Otherwise, replacing them with straight pipie won't make a lot of difference. Also, BMW cats last a long time. They should easily do 200,000 miles. |
Appreciate
0
|
04-25-2015, 04:08 PM | #27 |
Major
![]() 413
Rep 1,286
Posts |
If you are "welling" me, I gave it the old college try; in that I had everything disconnected and removed as per a header install write up TheSt|G had provided and I had three of the easier exhaust manifold nuts removed when I decided installing the headers really wasn't much fun, so I reassembled everything. However, I did manage to complete the secondary cat delete in the process. Part of my lack of enthusiasm is that I am only two days removed from having the flu for three days and I am still not feeling percent.
I will have the headers installed this week, I promise, as I know a good shop by my office with a few highly recommended BMW techs.
__________________
2012 Jet Black 328i Coupe / ESS Tuning Gen. 2 Supercharger / Evolution Racewerks Oil Cooler / BMS Oil Catch Can / BMW Performance Exhaust with Dinan Y Pipe / Eibach Pro Kit Springs / Koni FSD Shocks / MFactory LSD & Differential Bushings / Performance Rear Trailing Arms / BMW Performance Strut Brace / Stop Tech Slotted Rotors / Hawk HPS 5.0 / SS Brake Lines / Brass Guide Pins / M3 Front Control Arms, 28 MM FSB, Engine Cowl, and DCT Paddle Shifters / Michelin PSS / APEX ARC-8
|
Appreciate
0
|
04-25-2015, 05:55 PM | #28 | |
Lieutenant Colonel
![]() ![]() 187
Rep 1,677
Posts |
Quote:
![]()
__________________
![]() ![]() "O thou afflicted, tossed with tempest, and not comforted, behold, I will lay thy stones with fair colours, and lay thy foundations with sapphires." (Isaiah 54:11) |
|
Appreciate
0
|
04-25-2015, 10:26 PM | #29 | |||||
Custom User Title
![]() 412
Rep 1,337
Posts |
After the headers, not too bad - after the secondary cat delete, yes. I do not mind it. I was told by a friend it sounds like a modded E46 M3. I don't know if that's good or bad - considering it still sounds like a BMW and not a Honda, I'd say good
![]() Quote:
Quote:
Quote:
Quote:
Quote:
I did not need the off road tune, as per my research this is mainly needed for catless headers. It was their standard tune, with some feedback from one of my datalogged interstate runs at WOT in 4th. I did note of the header mod to AA as well as it reflected in the data I've logged, then sent back to them for a second, custom tune. Well, well, well! ![]()
__________________
|
|||||
Appreciate
0
|
04-25-2015, 10:31 PM | #30 | ||
Custom User Title
![]() 412
Rep 1,337
Posts |
Quote:
Quote:
Yeah, it's a real PITA. I did not even bother trying. I knew I'd just curse the time and pound my head against the wall. I hope you get it done at a good price. Again, it should be around 5 hours shop time.
__________________
|
||
Appreciate
0
|
04-25-2015, 11:33 PM | #31 |
Banned
![]() 83
Rep 466
Posts |
The dyno graph on the AFE website states no tune necessary and will not cause a cel light. having the AA off-road tune would not be needed. The question is if AA can extract more power from this header? Someone local to FL should go and getter done!!!!
|
Appreciate
0
|
04-26-2015, 09:30 AM | #32 |
Brigadier General
![]() ![]() 1233
Rep 3,778
Posts
Drives: '11 328i '19 M6
Join Date: Jan 2012
Location: DFW
|
That's what's going into my car after the cams, a Y collector followed by a 3" thinwall 304SS straight pipe exhaust with a low back pressure muffler or two, Coast Fabrication 17" glass packed with V-band clamps to make changing the packing easier every year. I _think_ Burns Stainless makes a Y collector with the correct spacing for the headers so it's a bolt-in but the rest of the exhaust has to be fabricated, typically by mitering and MIG welding the pipe so it angles back under the car to the stock tailpipe location. Then it's dropped, TIG welded together, and reinstalled.
No bends and minimum departure from a straight line line maximizes velocity, I think, and that's really all that matters. We'll be adding another type of Y adapter at the end so a couple of pieces of the 3" pipe can be added to duplicate the look of the PE tips but the usual termination is a single pipe with a slight turn-down to help with noise to meet track requirements.
__________________
2011 E90 328i 6MT, BMW Aero, CF hood/boot, PI+CAI+RM+3IM+BPC, SS+CI528+ThermoTec+SS#1+2XBurns, AKG 75D eng/trans, Al/Delrin diff/RS, CM 850, UCP, CAE, AKG DSSR, DiffsOnline 3.91 30/90 LSD+BW cooler, C&R, Setrab, Accusump, AST 3-way+Swift, Aurora PR+BW spherical, Vorshlag CPs, M3 brace+UR bar, ARC-8 18x8.5, 255 R1R, RB/CSL rotors+cooling, 135i calipers, RS29, RT700, Safecraft, OMP HTE-R+804F+QD Superquadro, 6pt cage+FIA, Braille, RT DL1Mk3
|
Appreciate
1
|
04-26-2015, 09:46 AM | #33 |
Banned
![]() 2465
Rep 9,004
Posts |
The biggest part of the exhaust system is going to be the Y pipe and the placement of it. Everything after it makes little to no impact on power.
|
Appreciate
1
|
04-26-2015, 10:29 AM | #34 |
Brigadier General
![]() ![]() 1233
Rep 3,778
Posts
Drives: '11 328i '19 M6
Join Date: Jan 2012
Location: DFW
|
Well, not necessarily. If not using a low back pressure muffler it's difficult to optimize flow velocity. Pipe diameter matters as does whether it's mandrel bent or mitered, etc. although it's not terribly critical. The Y-collector determines scavenging timing at the head so yes its placement is more critical than the others but its effectiveness can be reduced by poor downstream design choices, I think. You and hass know more about it than i do, I'm going by the results the guys at the shop have found by dyno'ing many many different exhaust configurations on their NA and turbo race cars.
__________________
2011 E90 328i 6MT, BMW Aero, CF hood/boot, PI+CAI+RM+3IM+BPC, SS+CI528+ThermoTec+SS#1+2XBurns, AKG 75D eng/trans, Al/Delrin diff/RS, CM 850, UCP, CAE, AKG DSSR, DiffsOnline 3.91 30/90 LSD+BW cooler, C&R, Setrab, Accusump, AST 3-way+Swift, Aurora PR+BW spherical, Vorshlag CPs, M3 brace+UR bar, ARC-8 18x8.5, 255 R1R, RB/CSL rotors+cooling, 135i calipers, RS29, RT700, Safecraft, OMP HTE-R+804F+QD Superquadro, 6pt cage+FIA, Braille, RT DL1Mk3
|
Appreciate
0
|
04-26-2015, 11:04 AM | #35 |
Major General
![]() ![]() ![]() 3966
Rep 7,215
Posts |
Right, it can be restrictive. But the stock cats are sized for the engne, so whatever flow restriction is present is minimal. It's no different than putting in an intake, the stock one is already pretty good so gains are minimal.
Headers make more power because they improve scavenging, have better merges, longer primaries, etc. If the only difference was the lack of cats, you could cut them off and make the same power as headers. While it will make a difference, headers still make more power. |
Appreciate
0
|
04-26-2015, 12:28 PM | #36 |
Lieutenant Colonel
![]() ![]() 187
Rep 1,677
Posts |
So...in your opinion, is it worthwhile to replace stock with the AFE catted headers while leaving the secondaries? (Note: I have the PE on my convertible and don't want it much louder.)
__________________
![]() ![]() "O thou afflicted, tossed with tempest, and not comforted, behold, I will lay thy stones with fair colours, and lay thy foundations with sapphires." (Isaiah 54:11) |
Appreciate
0
|
04-26-2015, 09:13 PM | #37 |
Banned
![]() 2465
Rep 9,004
Posts |
That's up to you - we haven't seen a real dyno proven increase, but they can/should add power. Otherwise those secondaries removed and that exhaust will probably be louder than you have now - Even with the AFE headers.
|
Appreciate
0
|
04-26-2015, 11:32 PM | #38 |
Banned
![]() 83
Rep 466
Posts |
If I already have secondary delete with PE, adding AFE header would make it louder? I don't think it would be anymore louder than it is already. What's funny is after upgrading to stage 3 manifold the PE+secondary delete did get just a bit louder but tolerable.
Anyone have vids on PE+secondary+AFE header? |
Appreciate
0
|
04-27-2015, 01:11 AM | #39 |
Enlisted Member
![]() ![]() 1
Rep 32
Posts |
The look mighty nice, but the arnt much diffrent to the OEM?
Or do US and Euro have diffrent headers? Mine look like this: ![]()
__________________
![]() E90 M-Sport 330i N53 272hp w Dynomax VT Muffler & Mod. OEM airbox w Ramair filter |
Appreciate
0
|
04-27-2015, 11:47 AM | #40 |
Resident Tamed Racing Driver
![]() 298
Rep 4,697
Posts |
Was it my DIY you referenced? If so, you should have felt free to PM me if you had any questions. AFE headers most definitely do not fall into my "tough shit you bought China junk" rule.
![]()
__________________
2005 E46 M3 Interlagos/Cinnamon with Sunroof Delete
|
Appreciate
0
|
04-27-2015, 12:25 PM | #41 |
Captain
![]() ![]() ![]() ![]() ![]() 91
Rep 611
Posts |
yes, US has different and more restricted header design, AFE uses euro design but with 300 cell cat.
__________________
N51- PI - PE - ESS Tuned - SSK - CDV Delete - AFE Header - B12 - Mfactory LSD
|
Appreciate
0
|
04-27-2015, 12:50 PM | #42 |
Resident Tamed Racing Driver
![]() 298
Rep 4,697
Posts |
Euro version was also only used on pre-facelift euro cars.
__________________
2005 E46 M3 Interlagos/Cinnamon with Sunroof Delete
|
Appreciate
0
|
04-27-2015, 03:04 PM | #44 |
Resident Tamed Racing Driver
![]() 298
Rep 4,697
Posts |
That's a pretty broad question, but to what it is relevant here, the N52 in Europe lost 6-7hp in the facelift when those headers changed to the worse US spec design.
__________________
2005 E46 M3 Interlagos/Cinnamon with Sunroof Delete
|
Appreciate
0
|
![]() |
Bookmarks |
|
|