[Dustin@AEp]

If you are looking for power, the AE Performance downpipe back system is for you!

There are many reviews of our system on this forum, so be sure to take a look!

If you have any questions regarding our system, feel free to shoot me an email.

Best Regards,


Dustin Boyko
Dustin.B@aeperformance.com

[packinDSS]

Originally Posted by scottp999

Dual 2.5" = 5"
vs
Single 3"

I'd take 5", plus you are not mixing pulses from both banks into one pipe. The more free flowing the better.

doesn't work that way............

The area of a circle is below. Actually dual 2.5 inch exhaust flows approx 25% more than a single 3inch exhaust

2 inch duals is 6.28
2 1/4 duals is 8.0
2 1/2 duals is 9.8
3 inch single is 7.0

[fl335i]

packin DSS- that's exactly the math I did. Area of a circle. HKS is using 65mm piping which is like 2.6" pipe. Massive pipe.

[Eric@AMS]

Our past AMS 335i running race gas was making 500whp through a set of CP-E catless downpipes and our AMS 3inch cat-back. Mitsubishi EVO's are making 900whp through a single 3inch exhaust. If you would like to correlate to a 6 cylinder, we have had multiple Nissan GT-R's 3.8L 6cyl making over 700whp through a 3inch system. Any single 3inch exhaust system on the market for the 135 or 335 should be efficient to 750whp. In all honesty, I personally do not know of any BMW's making that power, well at least not yet... In other words, a 3inch exhaust is good for a vehicle making stock power to a vehicle making a lot of power.

Also, any cat-back system on the market is not going to yield much in the way of power. The real horsepower numbers come from adding downpipes. BMW made a pretty well matched cat-back for the small stock turbo's. I am sure once you go bigger turbos a larger exhaust will yield more power.

Bottom line is that the exhaust sizing can be more accurately matched to the amount of air a car is moving. I think the GT-R comparison rings the most true as we are comparing a car with .8 more liters on two much bigger OEM turbo's moving a lot more air. Even in this case the 3" system doesn't start to really choke up the car until you breach that 700whp mark. Hope this helps.

[fl335i]

Eric- If you look at most of the cat-backs for a MK4 TT Supra they are 90mm piping, which is 3.543". They are also 3.0L I-6cyl TT's. Not arguing, just saying I kind of agree with a single exhaust, but maybe the 3" is 1/2" shy for big HP goals? Going based on rule of thumb exhaust charts the 3" is good for 350HP in theory. Hard to say... I wish that grassroots dyno shoot out had tested the AMS, Vanguard and Active Autowerke's while they were at it. B/c they're findings actually looked very honest. and I really want a light weight single exhaust that is proven apples vs apples. I just don't know how AA is claiming 15-22hp at the wheels.... when the most others are getting 8-13hp.

[BrianMN]

Don't take any of those claimed HP gains into consideration....

[fl335i]

^Amen to that.

[ar design]

Originally Posted by fl335i

Eric- If you look at most of the cat-backs for a MK4 TT Supra they are 90mm piping, which is 3.543". They are also 3.0L I-6cyl TT's. Not arguing, just saying I kind of agree with a single exhaust, but maybe the 3" is 1/2" shy for big HP goals? Going based on rule of thumb exhaust charts the 3" is good for 350HP in theory. Hard to say... I wish that grassroots dyno shoot out had tested the AMS, Vanguard and Active Autowerke's while they were at it. B/c they're findings actually looked very honest. and I really want a light weight single exhaust that is proven apples vs apples. I just don't know how AA is claiming 15-22hp at the wheels.... when the most others are getting 8-13hp.

Guys are making over 700whp on 3in. Not sure where that 350hp number came from, but it is not correct. We have made 450whp on the stock exhaust, no problem.

[scottp999]

Originally Posted by packinDSS

doesn't work that way............

The area of a circle is below. Actually dual 2.5 inch exhaust flows approx 25% more than a single 3inch exhaust

2 inch duals is 6.28
2 1/4 duals is 8.0
2 1/2 duals is 9.8
3 inch single is 7.0

Agree. Head must have been up my rear.

[fl335i]

Are they making that kind of power on 3" or 90mm ?

[ar design]

3". 90mm is 3.5"

[Penn999]

Originally Posted by Eric@AMS

Our past AMS 335i running race gas was making 500whp through a set of CP-E catless downpipes and our AMS 3inch cat-back. Mitsubishi EVO's are making 900whp through a single 3inch exhaust. If you would like to correlate to a 6 cylinder, we have had multiple Nissan GT-R's 3.8L 6cyl making over 700whp through a 3inch system. Any single 3inch exhaust system on the market for the 135 or 335 should be efficient to 750whp. In all honesty, I personally do not know of any BMW's making that power, well at least not yet... In other words, a 3inch exhaust is good for a vehicle making stock power to a vehicle making a lot of power.

Also, any cat-back system on the market is not going to yield much in the way of power. The real horsepower numbers come from adding downpipes. BMW made a pretty well matched cat-back for the small stock turbo's. I am sure once you go bigger turbos a larger exhaust will yield more power.

Bottom line is that the exhaust sizing can be more accurately matched to the amount of air a car is moving. I think the GT-R comparison rings the most true as we are comparing a car with .8 more liters on two much bigger OEM turbo's moving a lot more air. Even in this case the 3" system doesn't start to really choke up the car until you breach that 700whp mark. Hope this helps.

Are you sure you dont know of any BMW's making over 750whp? Maybe you meant N54's? Because I have seen quite a few S54's than run about make about that(750whp), and some that are well above that. If not I can provide you with a couple links to videos, with dynos and actual in car runs. Guess what beginning of all of the videos are.....HPF!

[BrianMN]

Originally Posted by Penn999

Are you sure you dont know of any BMW's making over 750whp? Maybe you meant N54's? Because I have seen quite a few S54's than run about make about that(750whp), and some that are well above that. If not I can provide you with a couple links to videos, with dynos and actual in car runs. Guess what beginning of all of the videos are.....HPF!

He obviously meant N54s.

Cool story though.

[Penn999]

Originally Posted by BrianMN

He obviously meant N54s.

Cool story though.

Well to me it looked like he said ANY BMW sooo...I was just making sure. N54's gonna need some serious internals to make those kinda numbers, and a lot stronger drive-train. Not to mention fuel and timing...

[sdstatestud88]

Love my Vanguard With Raceland soon to be on Saturday catless Downpipes...

[M3irish]

For any of the exhaust manufactures on this thread. Has SAE or any measurable sound testing been completed? I'm curious how loud the cat-backs actually are which will help in my decision.

Thanks,
Rob

[FVM3]

if you want sound, go for eisenmann race, cat back doesnt gain lot of hp

[Penn999]

Originally Posted by christopherchenm

if you want sound, go for eisenmann race, cat back doesnt gain lot of hp

I cant speak for esienmann, but I agree with him ^, You wont get any power if you leave the secondary cats in...only sound.

[fl335i]

HKS has a statement about legality. They are stating they meet the California bla bla bla. Only one I've seen that states they meet the 95db California crap. For me this is kind of an issue b/c FL cops like to pull the whole "your muffler is illegal b/c it's aftermarket (aka shiny lol), proove it's legal" card. And technically they are correct. Anytime you put an aftermarket muffler system on, it needs to be certified db rated or you can have your local sheriff certify it with their db meter. It's a gray area. After looking at all the exhaust systems they all have pros/cons. HKS seems to be the best overall. Fully Polished, fully flanged, twin 65mm piping, California Certified and only $1,600 bones. That and I really like the Titanium tips. (I think of my 335i as a 4 door Supra lol).

[Penn999]

Originally Posted by fl335i

HKS has a statement about legality. They are stating they meet the California bla bla bla. Only one I've seen that states they meet the 95db California crap. For me this is kind of an issue b/c FL cops like to pull the whole "your muffler is illegal b/c it's aftermarket (aka shiny lol), proove it's legal" card. And technically they are correct. Anytime you put an aftermarket muffler system on, it needs to be certified db rated or you can have your local sheriff certify it with their db meter. It's a gray area. After looking at all the exhaust systems they all have pros/cons. HKS seems to be the best overall. Fully Polished, fully flanged, twin 65mm piping, California Certified and only $1,600 bones. That and I really like the Titanium tips. (I think of my 335i as a 4 door Supra lol).

You get pulled even though you drive a 4 door bimmer?? Do you have any aero mods that would hint that you are modifying your car? Here in VA only the ricers(hondas, subies, evos...etc.) get pulled. If I ever get pulled I am gonna tell that fat pig that its the "M" package. haha, if he gives me some shit I will get my buddy at bmw to vouch for me. They really use the db test in FL? VA has it but never uses it. I thought they were pretty slack about that.

[fl335i]

I have a bone stock legally tinted debadged 4 door 335i. Never been pulled over in it. But I have been pulled over in my 4x4 trucks, Vette and Supra. The cops always pull over the polished exhausts. They gave my wife hell on her turbo supra b/c she had a Tanabe also. I had the manufactures 50 state legal and CARB cert # and FL statute in the glove box. 3 sheriff's cars pulled us over and harassed us and then let us go (she was driving!). Her car was QUIET. Cat-back only. Cop started telling me "I know cars, I have a SS camaro" and bla bla. I put up a bit of a fight and told the cops give me a ticket and I'm fighting it. I explained the car has cats, the aftermarket cat-back system is CARB certified etc and I will fight it and they let us go. I even offered to rev it for them. Funny thing was we were driving home from dinner at lke 9pm and driving like grandma. 40mph. Only reason he pulled us over was b/c the exhaust was polished. So I am making sure if I get pulled I am like wam, license registration proof of insurance and exhaust paper work. Best way to win a battle is know what kind of a battle you're getting in. I even keep a copy of everything aftermarket. Originals are at home in my car file. I have a copy of my window tint paper work to proove I have 30%/15% which is legal in FL. Usually when they pulled mod'd cars they probly don't get someone that is all paperworked up. So This is in my favor.

[Penn999]

Originally Posted by fl335i

I have a bone stock legally tinted debadged 4 door 335i. Never been pulled over in it. But I have been pulled over in my 4x4 trucks, Vette and Supra. The cops always pull over the polished exhausts. They gave my wife hell on her turbo supra b/c she had a Tanabe also. I had the manufactures 50 state legal and CARB cert # and FL statute in the glove box. 3 sheriff's cars pulled us over and harassed us and then let us go (she was driving!). Her car was QUIET. Cat-back only. Cop started telling me "I know cars, I have a SS camaro" and bla bla. I put up a bit of a fight and told the cops give me a ticket and I'm fighting it. I explained the car has cats, the aftermarket cat-back system is CARB certified etc and I will fight it and they let us go. I even offered to rev it for them. Funny thing was we were driving home from dinner at lke 9pm and driving like grandma. 40mph. Only reason he pulled us over was b/c the exhaust was polished.

LOL, well like I said, those cars are a little bit bigger targets, IMO. Def. the supra, they are MONSTERS. I have owned three BMW's, all with catless exhaust, no tickets and not even pulled over. I think they fly under the radar a lot better than people think unless you are WOT and blow right pass a piggy. Is yours AT or MT? AT drones a bit more and worse comes to worse you just pop the clutch in as you go by um. It honestly amazes me how many fuckin crack heads their are out here and they want to waste their time with someone who is actually a productive member of society, actually paying their fucking salary LOL!! our government at its finest....