How much HP/TQ will a DP back catless exhaust add?

cstmx_ryder · 07-01-2009, 04:58 PM

My mods are in my sig, my question is, with my set-up, how much more HP/TQ do you guys think I can squeeze out of my car?

I'm sitting right around 370whp/386wtq right now on 92 pump.

Is this really necessary to maximize my tune and mods? I think so. But I was told that the stock exhaust runs just fine with stock TT, no need to upgrade.

I disagree with that, what do you guys think?

Please chime in

TIA

Zeph · 07-01-2009, 05:00 PM

stock exhaust has cats and crushes. It will run "fine" but a catless exhaust with mandrel bends will run "finer"

Just be careful that you actually buy a dp back EXHAUST and not an axle back "exhaust" or you will still have crushes and cats...

335ievo · 07-01-2009, 05:00 PM

I would say its totally up to you...seems like you already made up your mind about it.

cstmx_ryder · 07-01-2009, 05:16 PM

What I said in my OP was just my opinion, or what I've learned about the N54 platform.

I'm always openminded and just would like to hear what others with the actual experience have to say......

Eric@AMS · 07-01-2009, 05:19 PM

as far as HP gains you will get answers all over the place but we did a back to back test with a couple different systems and average gains were about 15-20whp with a full down-pipe back system with no cats compared to the stock system.

Eric

BobVader · 07-01-2009, 05:44 PM

Quote:

Originally Posted by cstmx_ryder

My mods are in my sig, my question is, with my set-up, how much more HP/TQ do you guys think I can squeeze out of my car?

I'm sitting right around 370whp/386wtq right now on 92 pump.

Is this really necessary to maximize my tune and mods? I think so. But I was told that the stock exhaust runs just fine with stock TT, no need to upgrade.

I disagree with that, what do you guys think?

Please chime in

TIA

Probably 20 whp on dyno...but on the track...put race gas like ms109...better result than DP.

I have test both

cstmx_ryder · 07-01-2009, 05:47 PM

^^ 15-20 hp to the wheels? Is that with a tune, or just the exhaust, leaving everything else stock?

If that number is to the wheels with a tune, then it's better than I had expected.

Would you mind disclosing what type of DP back exhaust were being tested to come up with that number?

One more question: Since you guys deal with forced induced cars, would you go with a H-pipe like on the HKS exhaust, or go with the fully divorced pipes like on the AE exhausts. I believe the stock exhaust setup has an X-pipe post secondary cats, right?

I was originally going more towards the fully divorced pipes(AE exhaust), but if there's no performance difference, I like the HKS exhaust, but it has an H-pipe.

TIA

Zeph · 07-01-2009, 05:56 PM

I personally prefer divorced pipes on a twin turbo... like each turbo has its own exhaust with no H/X in place to cause disruption in flow.

On an N/A engine the H/X pipe is essential on a dual exhaust for load balancing, helping with the mid-range torque.

I think the only reason people like BMW and HKS have included an H/X on our cars' exhausts is to reduce drone. AE seems to be the only brand that was able to do that without using the H/X which is a big huge

for them.

Gen_E92 · 07-01-2009, 05:57 PM

Quote:

Originally Posted by cstmx_ryder

^^ 15-20 hp to the wheels? Is that with a tune, or just the exhaust, leaving everything else stock?

If that number is to the wheels with a tune, then it's better than I had expected.

Would you mind disclosing what type of DP back exhaust were being tested to come up with that number?

One more question: Since you guys deal with forced induced cars, would you go with a H-pipe like on the HKS exhaust, or go with the fully divorced pipes like on the AE exhausts. I believe the stock exhaust setup has an X-pipe post secondary cats, right?

I was originally going more towards the fully divorced pipes(AE exhaust), but if there's no performance difference, I like the HKS exhaust, but it has an H-pipe.

TIA

I don't think E90 has x-pipe, just a resonator. E92 use x-pipe.

Zeph · 07-01-2009, 06:01 PM

E90 isn't connected between the mufflers like an E92?

Eric@AMS · 07-01-2009, 06:05 PM

Quote:

Originally Posted by cstmx_ryder

^^ 15-20 hp to the wheels? Is that with a tune, or just the exhaust, leaving everything else stock?

If that number is to the wheels with a tune, then it's better than I had expected.

Would you mind disclosing what type of DP back exhaust were being tested to come up with that number?

One more question: Since you guys deal with forced induced cars, would you go with a H-pipe like on the HKS exhaust, or go with the fully divorced pipes like on the AE exhausts. I believe the stock exhaust setup has an X-pipe post secondary cats, right?

I was originally going more towards the fully divorced pipes(AE exhaust), but if there's no performance difference, I like the HKS exhaust, but it has an H-pipe.

TIA

That is with a tune and to the wheels. No need for an H-pipe on a turbo charged car. The least amount of back pressure the better. We tested our prototype turbo back as well as a set of catless Riss racing dp's combined with an AE exhaust.

I notice you already have downpipes. Even if they are catted going to a catback and catless DP's I would not expect more than say 10whp over what you have unless they are using VERY restrictive high flow cats.

Eric

645Nm · 07-02-2009, 01:20 PM

I agree with Eric@AMS.

I am assuming you have CATTED Riss DPs.
Heres my suggestion: From Catted Dps - keep OEM secondary cats in place AND pipes in between - remove resonator if you have one and replace with X pipes - from here replace OEM mufflers. Or instead of bits and pieces get a full catback exhaust system running from AFTER the second cats as per above.
Your HP370 and 386TQ are serious performance numbers already and a true catback system as per my suggestion will give you better numbers and driveability.
Removing the secondary OEM cats and replacing your CATTED DPs (if you have) for catless DPs will ONLY increase your existing numbers marginally and give you future driveability issues - (If you had JB3, I would have said just run a higher race map with race fuel to get what you MIGHT get with a catless system.)

See attached picture: In a nutshell ONLY remove the parts in the picture:

cstmx_ryder · 07-02-2009, 01:46 PM

^^ I have RR CL DPs already. I also want a full bolt on DP back exhaust. No cutting, clamping or welding!

I was hoping to see around 390 hp and 400 tq with the addition of a catless exhaust. Maybe even bump up the UT values a little to obtain that goal.

Looks like AE exhausts are the way to go......??

gian335 · 07-02-2009, 02:08 PM

If ur gonna grab a downpipe back exhaust, than grab the ae,, it is the least obtrusive from day 2 day driving... Very little2 no drone at all. I'm completely catless and it sounds amaziing.... U will again around 15 whp on top of what u have now

645Nm · 07-03-2009, 01:43 PM

Keep us updated on your plans.

Kelvin1000 · 07-03-2009, 01:47 PM

What is the gain from JB3 1.3 to JB3 1.3 with RR downpipes and the rest of the stock exhaust (with the second cats still in place)?

07-01-2009, 04:58 PM	#1
cstmx_ryder Colonel 164 Rep 2,875 Posts Drives: A metal box with a roundel Join Date: Jul 2007 Location: Portland, OR iTrader: (2)	How much HP/TQ will a DP back catless exhaust add? My mods are in my sig, my question is, with my set-up, how much more HP/TQ do you guys think I can squeeze out of my car? I'm sitting right around 370whp/386wtq right now on 92 pump. Is this really necessary to maximize my tune and mods? I think so. But I was told that the stock exhaust runs just fine with stock TT, no need to upgrade. I disagree with that, what do you guys think? Please chime in TIA __________________ '08 AW E90 335i PROcede V5 \| BMS DCI \| RR DPs \| ETS FMIC \| FORGE DVs \| Stett CP \| Vanguard \| PSS10
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07-01-2009, 05:00 PM	#2
Zeph Major 27 Rep 1,410 Posts Drives: 2008 E92 335i 6MT SGM CR/BD Join Date: Jul 2008 Location: Southeast USA iTrader: (0)	stock exhaust has cats and crushes. It will run "fine" but a catless exhaust with mandrel bends will run "finer" Just be careful that you actually buy a dp back EXHAUST and not an axle back "exhaust" or you will still have crushes and cats...
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07-01-2009, 05:00 PM	#3
335ievo Your'e gonna learrrrrrnn tooooday 38 Rep 595 Posts Drives: 2013 BMW 328i M Sport EB Join Date: Mar 2008 Location: ATL, Georgia iTrader: (1)	I would say its totally up to you...seems like you already made up your mind about it. __________________ 2013 BMW 328i MSport F30 - Estoril Blue "Minds are like parachutes. They only function when they are open." James Dewar
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07-01-2009, 05:16 PM	#4
cstmx_ryder Colonel 164 Rep 2,875 Posts Drives: A metal box with a roundel Join Date: Jul 2007 Location: Portland, OR iTrader: (2)	What I said in my OP was just my opinion, or what I've learned about the N54 platform. I'm always openminded and just would like to hear what others with the actual experience have to say...... __________________ '08 AW E90 335i PROcede V5 \| BMS DCI \| RR DPs \| ETS FMIC \| FORGE DVs \| Stett CP \| Vanguard \| PSS10
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07-01-2009, 05:19 PM	#5
Eric@AMS Captain 71 Rep 726 Posts Drives: 2007 335i Join Date: Sep 2008 Location: West Chicago, IL iTrader: (5)	as far as HP gains you will get answers all over the place but we did a back to back test with a couple different systems and average gains were about 15-20whp with a full down-pipe back system with no cats compared to the stock system. Eric
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07-01-2009, 05:47 PM	#7
cstmx_ryder Colonel 164 Rep 2,875 Posts Drives: A metal box with a roundel Join Date: Jul 2007 Location: Portland, OR iTrader: (2)	^^ 15-20 hp to the wheels? Is that with a tune, or just the exhaust, leaving everything else stock? If that number is to the wheels with a tune, then it's better than I had expected. Would you mind disclosing what type of DP back exhaust were being tested to come up with that number? One more question: Since you guys deal with forced induced cars, would you go with a H-pipe like on the HKS exhaust, or go with the fully divorced pipes like on the AE exhausts. I believe the stock exhaust setup has an X-pipe post secondary cats, right? I was originally going more towards the fully divorced pipes(AE exhaust), but if there's no performance difference, I like the HKS exhaust, but it has an H-pipe. TIA __________________ '08 AW E90 335i PROcede V5 \| BMS DCI \| RR DPs \| ETS FMIC \| FORGE DVs \| Stett CP \| Vanguard \| PSS10
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07-01-2009, 05:56 PM	#8
Zeph Major 27 Rep 1,410 Posts Drives: 2008 E92 335i 6MT SGM CR/BD Join Date: Jul 2008 Location: Southeast USA iTrader: (0)	I personally prefer divorced pipes on a twin turbo... like each turbo has its own exhaust with no H/X in place to cause disruption in flow. On an N/A engine the H/X pipe is essential on a dual exhaust for load balancing, helping with the mid-range torque. I think the only reason people like BMW and HKS have included an H/X on our cars' exhausts is to reduce drone. AE seems to be the only brand that was able to do that without using the H/X which is a big huge for them.
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07-01-2009, 06:01 PM	#10
Zeph Major 27 Rep 1,410 Posts Drives: 2008 E92 335i 6MT SGM CR/BD Join Date: Jul 2008 Location: Southeast USA iTrader: (0)	E90 isn't connected between the mufflers like an E92?
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07-02-2009, 01:20 PM	#12
645Nm only in it for the torque - awuleth'umshini wami 50 Rep 425 Posts Drives: sapphire black 335i Join Date: Apr 2009 Location: nomad iTrader: (0) Garage List 2009 335i sedan [0.00] 2005 120D [0.00] 2007 335i sedan [0.00]	I agree with Eric@AMS. I am assuming you have CATTED Riss DPs. Heres my suggestion: From Catted Dps - keep OEM secondary cats in place AND pipes in between - remove resonator if you have one and replace with X pipes - from here replace OEM mufflers. Or instead of bits and pieces get a full catback exhaust system running from AFTER the second cats as per above. Your HP370 and 386TQ are serious performance numbers already and a true catback system as per my suggestion will give you better numbers and driveability. Removing the secondary OEM cats and replacing your CATTED DPs (if you have) for catless DPs will ONLY increase your existing numbers marginally and give you future driveability issues - (If you had JB3, I would have said just run a higher race map with race fuel to get what you MIGHT get with a catless system.) See attached picture: In a nutshell ONLY remove the parts in the picture: Attached Images __________________
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07-02-2009, 01:46 PM	#13
cstmx_ryder Colonel 164 Rep 2,875 Posts Drives: A metal box with a roundel Join Date: Jul 2007 Location: Portland, OR iTrader: (2)	^^ I have RR CL DPs already. I also want a full bolt on DP back exhaust. No cutting, clamping or welding! I was hoping to see around 390 hp and 400 tq with the addition of a catless exhaust. Maybe even bump up the UT values a little to obtain that goal. Looks like AE exhausts are the way to go......?? __________________ '08 AW E90 335i PROcede V5 \| BMS DCI \| RR DPs \| ETS FMIC \| FORGE DVs \| Stett CP \| Vanguard \| PSS10
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07-02-2009, 02:08 PM	#14
gian335 Major 36 Rep 1,031 Posts Drives: e92 335 Join Date: Apr 2008 Location: uknown iTrader: (1)	If ur gonna grab a downpipe back exhaust, than grab the ae,, it is the least obtrusive from day 2 day driving... Very little2 no drone at all. I'm completely catless and it sounds amaziing.... U will again around 15 whp on top of what u have now
	Appreciate 0 Quote

07-03-2009, 01:43 PM	#15
645Nm only in it for the torque - awuleth'umshini wami 50 Rep 425 Posts Drives: sapphire black 335i Join Date: Apr 2009 Location: nomad iTrader: (0) Garage List 2009 335i sedan [0.00] 2005 120D [0.00] 2007 335i sedan [0.00]	Keep us updated on your plans. __________________
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07-03-2009, 01:47 PM	#16
Kelvin1000 Major 253 Rep 1,297 Posts Drives: 2019 BMW M2 Competition MT Hoc Join Date: Sep 2007 Location: Miami, FL iTrader: (4)	What is the gain from JB3 1.3 to JB3 1.3 with RR downpipes and the rest of the stock exhaust (with the second cats still in place)?
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