[tarekelsakka]

I want to start off by saying I've never done any performance modifications on any of my cars before, except my previous F30 316i which was basically ruined because of a bad ECU remap.

I have decided I will not go the remap route but I want to improve the response and sound of my 330i. The performance is already good and the roads where I live aren't set up to driving fast anyways, but I'd really love a slightly better, deeper sound as well as less turbo lag and an improved throttle response. I have done a lot of research about this and from my understanding, a catless downpipes will definitely improve all of those even on a stock map.

I do have a few questions before I go ahead and install a downpipe:

1) I've seen conflicting posts about this, but will the car really smell like gas and stuff because of removing the cat? I don't mind if the car smells like that from the outside but I don't want to be driving in a car that smells emissions.

2) A lot of kids where I live do certain mods that make the car crackle and pop really loud and I actually hate that, so is that a side effect of installing a downpipe? Or does it take more than just that? As in bootmod, different maps, etc.?

3) I see a lot of claims that a catless downpipe will automatically give you a +25hp boost but I'm calling BS on this one. I am not looking for a performance gain, but to reduce turbo lag and improve throttle response, so is that achievable?

4) Am I going to get any check engine lights / errors after installing a downpipe? I heard that you'd need a stage 2 mod in order to avoid that. Is that true? Can't I just run it stock?

5) The pipe and installation will cost me around $450 USD, so is it worth it if I am going to keep everything else stock?

Thanks a lot for taking the time to read this and would appreciate your advice!

[mike@x-ph.com]

1)yes. the fuel smell is noticeable on cold start and when idle

2) your flash tune controls the burble. The downpipe makes it louder, but the tune is essential in activating it

3)catless downpipe will remove restrictions allowing your turbo to spool faster and reach a higher boost. You will need a new map targeting a higher boost to make substantial power increase

4)you can run it stock; the car runs normally. But you will have a check engine light that you'll have to ignore or get it cleared with a flash tune

5)that's a personal decision

[Skyhigh]

Already answered but here another set of answers:

1. Yes, it smells appreciably. And yes, you will be noticing it inside as well, when stationary, when being around the car, in garages and parking lots.

2. No it is not. The lack of cat amplifies whatever sound you have already. It does not create new sounds on its own (or if it does - there is something wrong with it)

3. Not BS. It does give immediate power increase, even without a tune and it is measurable (own experience talking). 25HP may however be a bit exaggerated, especially for 30i. Expect 10-15PS gain and some extra torque.

4. Yes you will get a CEL straight away. Unless you have a tune (what stage is completely irrelevant) which will disable the cat efficiency check.

5. Your call. Especially if you are keeping everything stock, IMO the only reasonable thing to do is to install a high-flow sport-cat DP which still maintains stock emissions. This means no CEL, no smell, but still better sound and noticeably improved performance (subjectively speaking, for an exhaust mod only). One downside - you need to multiply the cost.

[tarekelsakka]

Originally Posted by Skyhigh

Already answered but here another set of answers:

1. Yes, it smells appreciably. And yes, you will be noticing it inside as well, when stationary, when being around the car, in garages and parking lots.

2. No it is not. The lack of cat amplifies whatever sound you have already. It does not create new sounds on its own (or if it does - there is something wrong with it)

3. Not BS. It does give immediate power increase, even without a tune and it is measurable (own experience talking). 25HP may however be a bit exaggerated, especially for 30i. Expect 10-15PS gain and some extra torque.

4. Yes you will get a CEL straight away. Unless you have a tune (what stage is completely irrelevant) which will disable the cat efficiency check.

5. Your call. Especially if you are keeping everything stock, IMO the only reasonable thing to do is to install a high-flow sport-cat DP which still maintains stock emissions. This means no CEL, no smell, but still better sound and noticeably improved performance (subjectively speaking, for an exhaust mod only). One downside - you need to multiply the cost.

I know it's been months but I put off the idea for a while because I've been busy and haven't really had any extra cash to spend on the car but I'm finally ready to take the plunge. Since I don't want to spend a lot of money, I have been considering the VRSF downpipe and a K&N dropin filter with higher flow. My question is, do I have to install a better intercooler and/or charge pipe to handle the extra boost without compromising temperatures? Or would it be just fine?

I'm also looking into bootmod3 for later on, but I understand it would definitely require a cold air intake and an upgraded intercooler and charge pipe to handle the extra boost especially in a hot climate (reaches 40 degrees celsius in the summer where I live sometimes), however do I still need them if I am only installing a DP?

I found a high-flow dp by armytrix like the one you were talking about but it's literally more than double the price so I'm not sure if I want to go for that.

[Skyhigh]

Most of your questions are better asked in the B48 sub-forum (https://f30.bimmerpost.com/forums/fo...play.php?f=422) and not in the B58 sub-forum, since they are specific to your 30i engine, which is very different from the 40i.
You could ask the mods to move your entire thread there.

The only advice I can give you is that with Downpipes, you quite often get what you pay for... Not saying you should go for the most expensive one out there, but going for the cheapest equals starting a ticking-clock. This applies especially to the catted versions.

[tarekelsakka]

Skyhigh wow I didn't even realize I created this thread in the B58 forum, apologies for this. But thank you for your advice, I really appreciate it. And you're right, the Cermic Coated ArmyTrix High-Flow Performance Race Downpipe is supposed to be one of the best out there and doesn't even throw out errors, but the price is about $900 USD whereas the VRSF would cost me less than $300 USD so you can see I have a lot to think about, especially because I might end up using it for a couple of days then reselling it and putting back my catalytic converter if I don't like it so I don't want to overspend.

[G.Newt]

Originally Posted by tarekelsakka

Skyhigh wow I didn't even realize I created this thread in the B58 forum, apologies for this. But thank you for your advice, I really appreciate it. And you're right, the Cermic Coated ArmyTrix High-Flow Performance Race Downpipe is supposed to be one of the best out there and doesn't even throw out errors, but the price is about $900 USD whereas the VRSF would cost me less than $300 USD so you can see I have a lot to think about, especially because I might end up using it for a couple of days then reselling it and putting back my catalytic converter if I don't like it so I don't want to overspend.

I highly suggest you watch kern417 on YouTube. He most likely had a video for whatever you have a question for. B58 stuff also applies to B48 in a lot of ways.

[AMG KLR]

I am catless. I like the smell personally but to be fair I rarely smell it from inside the cabin, even when the windows are down

[BMWILUVU]

On the B58 you may get an extra 15-20hp standalone but seriously doubt you will get that on the B48 as you're not moving as much air. Also depends on how restrictive the B48 cat is. I would say a DP is not worth it on the B48 without a tune.

[dinan5m3]

Originally Posted by BMWILUVU

On the B58 you may get an extra 15-20hp standalone but seriously doubt you will get that on the B48 as you're not moving as much air. Also depends on how restrictive the B48 cat is. I would say a DP is not worth it on the B48 without a tune.

If that 15-20 hp gain on non-catted, then compared to high-flow 400 cell catted DP (for instance ActiveAutowere B58 DP) which is about 3 times the cost of non-catted, just how much one can expect with proper tune, to gain going from high flow catted to non-catted?

AA high-flow 400 cell catted DP - ~$1,200
AA non-catted DP - $399

[blacksapphire440i]

Originally Posted by dinan5m3

If that 15-20 hp gain on non-catted, then compared to high-flow 400 cell catted DP (for instance ActiveAutowere B58 DP) which is about 3 times the cost of non-catted, just how much one can expect with proper tune, to gain going from high flow catted to non-catted?

AA high-flow 400 cell catted DP - ~$1,200
AA non-catted DP - $399

Well I don't think we can give you exact numbers, but the catless will give you more POTENTIAL to flow more air compared to the high flow cat.

[Info@mad-us.com]

Few of your questions seem to have already been answered but here is my take.

Pro's -
1.Going catless makes your exhaust sound amazing
2. It will add Horsepower and will have less turbo lag and this goes for stock tuned vehicle but even more once you start turning up the boost.

Negatives-
1.Possible gas smell ( me personally don't mind it at all)
2.Check engine light will come on. This can be eliminated with a tune or you can buy a hand held scanner $35 and just clear it every-time it appears

We have them in stock if you decide to go this route.

https://mad-us.com/mad-b58-downpipe-...chassis-supra/


EDIT:: I see you are 330. If it's a B48 use this link for your downpipe https://mad-us.com/mad-bmw-f-g-chass...0-420-430-730/

[tarekelsakka]

Originally Posted by Info@mad-us.com

EDIT:: I see you are 330. If it's a B48 use this link for your downpipe https://mad-us.com/mad-bmw-f-g-chass...0-420-430-730/

Thank you for your reply. That downpipe looks fantastic and I'm loving the price too, but I'm assuming you don't have any resellers in Egypt? Shipping & customs will cost me an arm and a leg.

[Info@mad-us.com]

Originally Posted by tarekelsakka

Thank you for your reply. That downpipe looks fantastic and I'm loving the price too, but I'm assuming you don't have any resellers in Egypt? Shipping & customs will cost me an arm and a leg.

Thanks for the kind words! We do have some dealers in Lebanon which isnt to far away

https://mad-us.com/dealers/