Fiesta ST Downpipe Thread

[TurboRon]

I got a question for you guys. Seeing as (from what I just read) that all the downpipes are pretty much compatible with the 2.5" exhausts (like Cobb), would it benefit me to go with the Cobb DP compared to say, the 2JR DP?

I am running the Cobb Cat-Back and I want the DP now to complete the setup, but my problem is that while I love Cobb and wanna go with plenty of their beautiful parts, that $495 price tag on their Cat DP makes me cringe a tiny bit. When you compare it to the 2JR at half the price, it looks really good to go with in comparison.

So those with the 2JR and those with the COBB, how have they been to you and what was the rest of your setup?

I went through this thread with no "direct" answer or good information on how everything really worked out. I get the "I like the noise and turbo spool is faster" aaaaaaand that was about it. But those people nearly all had a tune. From there I got mixed stuff on whether a CEL light would go off or not. I don't want my dealership to know I've been screwing with the car that much...even though my BOV adapter should have given them a hint already. Oh yeah and that boost gauge tube going through the engine. *ahem* anyway.

My 2 current DPs I am looking at are the COBB Catted DP and the 2JR Catless.
Reason for Cobb is that it would complete my exhaust setup as full COBB and the COBB has been sounding great so far so I see no reason to stray.
Reason for 2JR is due to it being catless, it is much cheaper first off, then from what I have read is that going without a cat is better for flow thus giving more power and improving performance(?) But then I worry about the CEL because I am not running a cat and then smog issues and then my dad is gonna whine because now my car is illegal and blah blah blah!

Anyone got an answer for me? Sorry I'm so spazzy, I'm a special snowflake. This is the first time I've ever modified a car to this degree and my last Fiesta had an intake that was on for maybe 300 miles before the accident (STUPID COROLLA!).

The real questions are:
Does your state have emissions testing? if yes, you might have to go catted to pass.
Does the brand matter? I think not. The real issue you need to decide is catted vs catless !
Can you handle a little black smoke to get max power? Yes - go catless.
As for CEL - there are easy fixes for any DP generated CELs - adapters and custom tunes, so in my opinion only a secondary concern.

 

[MOFiST]

How much extra smoke does a catless pipe generate? Is it mainly during warm up and WOT? Anyone that has one do you find more carbon soot build up around the exhaust exit area?

 

[TurboRon]

Each car is different, varies with mods, tune, climate, etc. you are likely to see some soot stains especially around exhaust tip- again varies with exhaust brand, etc (some stick out more than others) see youtube vids

 

[SirSlaughter]

Hey thanks for the info guys. I know more than I did a few days ago.

Here in TN we don't have testing (that I know of) so I should be good to go. Worst case scenario is that something happens and i need to put the stock DP back on for a bit.
I don't mind black smoke. I've been ragging the shit outta my Fiesta the last few days and if you saw my exhaust tips you would think I had a catless. (Smells like fireworks)
I do tend to be one of those brand loyalist people but I always give credit where credit is due when someone else makes something awesome so I don't really care too much on brand so long as it's proper.
For the CEL I have the AP on my list of things to do so worst case is I see a CEL and maybe decide to leave the stock DP on for a little until I get a tune if the light bothers me that much.

 

[Sourskittle]

The de-foulers cost a little but but work.

 

[Svvift]

yeah i have a 90* o2 cheater that was about 10-15 bucks and its awesome. over 3k miles and no CEL *knocks on wood*

 

[TurboRon]

Hey thanks for the info guys. I know more than I did a few days ago.

Here in TN we don't have testing (that I know of) so I should be good to go. Worst case scenario is that something happens and i need to put the stock DP back on for a bit.
I don't mind black smoke. I've been ragging the shit outta my Fiesta the last few days and if you saw my exhaust tips you would think I had a catless. (Smells like fireworks)
I do tend to be one of those brand loyalist people but I always give credit where credit is due when someone else makes something awesome so I don't really care too much on brand so long as it's proper.
For the CEL I have the AP on my list of things to do so worst case is I see a CEL and maybe decide to leave the stock DP on for a little until I get a tune if the light bothers me that much.

The CPe catless DP comes with a defouler included and is reasonable in price. check it out. others have used it report no CEL.

 

[JPGC]

Has anyone data logged before and after use of the defouler on these cars. COBB says don't use a defouler. Just because there is no CEL for the cat, doesn't mean that all is well.

 

[TurboRon]

Interesting question, and one I voiced before as well with no clear response. If there is a catted DP with no CEL then the effect on computer is not as significant as a catless DP that throws a CEL.
If the o2 sensor is used by the computer to determine AFR etc, how does the defouler affect the rich / lean mixture, etc?
To go back to the cause ...I'm guessing that the catless DP will throw off ECU readings and cause CEL by showing too much unburned fuel = telling the computer mixture is too rich and cause it to lean out the mixture. Therefore the defouler should help correct that imbalance by showing the computer what it thinks it should see if the standard AFR setting is right. Less unburned gas = no need for a radical AFR correction. So driving around with a CEL is probably less than safe. the defouler should be a step in the right direction to "un-confuse" the computer. However, as we have long figured out - data logging followed by a good custom tune will solve the issue anyway.

 

[rooSTer]

Has anyone data logged before and after use of the defouler on these cars. COBB says don't use a defouler. Just because there is no CEL for the cat, doesn't mean that all is well.

I remember reading the same..both Cobb and Mountune suggest not to use defoulers and if you have a tune there is no reason to since the CEL can be deactivated. I would assume the defouler is mainly used by people that do not have a tune.

 

[Svvift]

yeah i currently don't have a tune. First new car and want to keep it under warranty as long as possible. but i will probably pull that trigger once i hit 10k miles.
my thought, if something is going to fail, it will fail by then

 

[TurboRon]

I would guess the defouler is still beneficial with a catless as will require a less radical tune.
If you replace a cat with another cat not as big of a problem. Computer still happy.
Go catless and the ECU says WTF?!

 

[rodmoe]

I would guess the defouler is still beneficial with a catless as will require a less radical tune.
If you replace a cat with another cat not as big of a problem. Computer still happy.
Go catless and the ECU says WTF?!

Um Ok but I have had both Catted and now catless both throw codes .. The defouler according to COBB mess's with fuel trim (up to 20% if I recall) and work require a more radical tune than without to keep your AF ratio correct ..
If you run a Stg 3 tune the code for cat eff is turned off in most cases ..

 

[TurboRon]

I don't doubt any of your statements.

Um Ok but I have had both Catted and now catless both throw codes.

That's because an aftermarket catted is still freer flowing and may not clean emissions as well as a stock cat. so sensor still sees the difference in reading and is not happy (depending on the brand / application, and other parts.) The sensor downstream of the cat is like an electronic nose, sniffing for unburned fuel. If it smells any it will probably assume it is the AFR out of wack because It's not programmed to look for aftermarket parts!!!

The defouler according to COBB mess's with fuel trim (up to 20% if I recall) and work require a more radical tune than without to keep your AF ratio correct ..

This may be true for their catted DP and not necessarily for others. also remember we all have different mixes of parts and tunes, so there is not necessarily 1 correct answer.
I'm just using general logic that was usually true for cars I had in the past. if the sensor siting in the middle of the exhaust stream smells 10 particles of unburned gas, if u back it out of the direct flow of exhaust gasses with a defouler and now it smells only 2 particles, You will generally have less of a correction to make to computer happy. and in days gone by was all we needed to eliminate the CEL and there was no need for any further adjustment. But admittedly, things have changed!!!

If you run a Stg 3 tune the code for cat eff is turned off in most cases ..

ahh progress. You gotta love it.

 

[Joszer]

I got a question for you guys. Seeing as (from what I just read) that all the downpipes are pretty much compatible with the 2.5" exhausts (like Cobb), would it benefit me to go with the Cobb DP compared to say, the 2JR DP?

I am running the Cobb Cat-Back and I want the DP now to complete the setup, but my problem is that while I love Cobb and wanna go with plenty of their beautiful parts, that $495 price tag on their Cat DP makes me cringe a tiny bit. When you compare it to the 2JR at half the price, it looks really good to go with in comparison.

So those with the 2JR and those with the COBB, how have they been to you and what was the rest of your setup?

I went through this thread with no "direct" answer or good information on how everything really worked out. I get the "I like the noise and turbo spool is faster" aaaaaaand that was about it. But those people nearly all had a tune. From there I got mixed stuff on whether a CEL light would go off or not. I don't want my dealership to know I've been screwing with the car that much...even though my BOV adapter should have given them a hint already. Oh yeah and that boost gauge tube going through the engine. *ahem* anyway.

My 2 current DPs I am looking at are the COBB Catted DP and the 2JR Catless.
Reason for Cobb is that it would complete my exhaust setup as full COBB and the COBB has been sounding great so far so I see no reason to stray.
Reason for 2JR is due to it being catless, it is much cheaper first off, then from what I have read is that going without a cat is better for flow thus giving more power and improving performance(?) But then I worry about the CEL because I am not running a cat and then smog issues and then my dad is gonna whine because now my car is illegal and blah blah blah!

Anyone got an answer for me? Sorry I'm so spazzy, I'm a special snowflake. This is the first time I've ever modified a car to this degree and my last Fiesta had an intake that was on for maybe 300 miles before the accident (STUPID COROLLA!).

I've had my catless 2JR mated to the 2JR exhaust since August without a single CEL come on. Since I bought my car new I don't have to smog it in 7 years in California. By 7 years time my Fiesta will be sold so I am not worried about it.

 

[TurboRon]

Dyam son, you got a lotta goodies on your ride!!! ...

 

[TW@]

Not sure if this has been answered yet but how much more power are you going to get with a decat downpipe as apposed to a catted one?

 

[felopr]

Not sure if this has been answered yet but how much more power are you going to get with a decat downpipe as apposed to a catted one?

this information is provided by @2jracing, they did all the research, i am just copy/pasting there info from http://www.2j-racing.com/fiesta-st-full-race-street-downpipe.html

The difference in WTQ vs the OEM downpipe is over 30ft/lbs.
With our 2JR 3" Catback, Full Race DP, Cobb AP (93map V1), and K&N Drop in Filter - we clicked off continuous 247-251wtq runs with varying between 200-202 whp.
With the 2JR catted DP and the same mods, we turned mid 230wtq.
Race DP = decatted

 

[redsilvy]

JUst ordered an ATP catless from Mod Bargains. Looking forward to getting that in.

 

[redsilvy]

Well I got mine on last night. Have driven maybe 30 miles and have a CEL on now.

For you guys using the Cobb AP, what tune are you running to get the CEL to go away?