DP as only mod: safe and hassle-free?

D

desperado-c

Member
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Mazdaspeed3
So, long story short, for perhaps paranoid reasons I have taken off my CAI, put the stock box back on, and returned my AP. I am now considering getting either the CP-E or the Cobb catted DP (when it comes out) as my only power mod. While it might be optimum to run a downpipe and a CAI and EMS, I don't know if I want to pony up $1300-$1600 for EMS and a downpipe.

What I'm wondering is can these DP's be run by themselves without complications or are CELs, boost cut, and therefore an EMS unavoidable?

The power gain from a DP alone is still pretty substantial with CP-E's TBE dyno showing gains of 40/20 whp at 4700/5500 RPMs respectively and Cobb's dynos showing that, with AP at least, St2 gains are pretty much the same as St2+ up to 5K RPMs. And safety-wise, it seems to me that I would be decreasing the BPTB ratio and presumably keeping correspondent pre-turbo EGT's at stock levels or below by keeping the restrictive intake.
 
desperado-c said:
So, long story short, for perhaps paranoid reasons I have taken off my CAI, put the stock box back on, and returned my AP. I am now considering getting either the CP-E or the Cobb catted DP (when it comes out) as my only power mod. While it might be optimum to run a downpipe and a CAI and EMS, I don't know if I want to pony up $1300-$1600 for EMS and a downpipe.

What I'm wondering is can these DP's be run by themselves without complications or are CELs, boost cut, and therefore an EMS unavoidable?

The power gain from a DP alone is still pretty substantial with CP-E's TBE dyno showing gains of 40/20 whp at 4700/5500 RPMs respectively and Cobb's dynos showing that, with AP at least, St2 gains are pretty much the same as St2+ up to 5K RPMs. And safety-wise, it seems to me that I would be decreasing the BPTB ratio and presumably keeping correspondent pre-turbo EGT's at stock levels or below by keeping the restrictive intake.
Click to expand...

I don't for what is worth. I would go catted if you "really" want a downpipe.

I had my experiences with SRT-4s. Everyone swears by a downpipe. And especially if it is catless. Saying that the SRT yields great gains. yada yada.

Yet all the same mods this was the break down of dyno's with the SRT-4.

HKS Catless 3in Downback going into 3in catback.
245whp 280tq

3in cut-out pre-cat
239whp 272tq

Stock Downpipe w/cat, Mopar Cat-back Exhaust
244whp 278tq(also the fastest setup at the track 13.6@107)

The last was the best setup hands down. Not too loud at all, and for a 1whp loss. I am willing to deal with that.

But I have seen cats from bypassing the catback in my T/A as well I gained 10whp 12tq from bypassing it(Cutout). And that was already with a more flowing muffler.

IMO, if there are gains to be had. Do the catback. Leave the rest alone. Also better for emission checks, and warranty visits.
 
Nachtsturm said:
I don't for what is worth. I would go catted if you "really" want a downpipe.

I had my experiences with SRT-4s. Everyone swears by a downpipe. And especially if it is catless. Saying that the SRT yields great gains. yada yada.

Yet all the same mods this was the break down of dyno's with the SRT-4.

HKS Catless 3in Downback going into 3in catback.
245whp 280tq

3in cut-out pre-cat
239whp 272tq

Stock Downpipe w/cat, Mopar Cat-back Exhaust
244whp 278tq(also the fastest setup at the track 13.6@107)

The last was the best setup hands down. Not too loud at all, and for a 1whp loss. I am willing to deal with that.

But I have seen cats from bypassing the catback in my T/A as well I gained 10whp 12tq from bypassing it(Cutout). And that was already with a more flowing muffler.

IMO, if there are gains to be had. Do the catback. Leave the rest alone. Also better for emission checks, and warranty visits.
Click to expand...


This isnt an srt-4... The catback for our cars does nearly nothing... something like you lose 1 hp, and gain 5 torque or soemting like that.

a full downpipe(like cp-es, or eventually cobb's) will give great results.
I dont know why youre so scared of the other mods though...
With the AP you can just flash it back to stock... with an intake, it's simple to install and uninstall.
With the EMS it will probably run safer than without it... It drives smoother and better with the AP installed than just the stock ms3..
I'm sure you'll have morep ower with just the downpipe over the intake and ap.

I think you should reinstall your intake, and get the AP again.. It'll drive smoother, and a lot faster.
If you're willing to uninstall the dp in case of warranty work, the intake and AP will only take an extra 30 or sominutes...
 
numbnuts22715 said:
This isnt an srt-4... The catback for our cars does nearly nothing... something like you lose 1 hp, and gain 5 torque or soemting like that.

a full downpipe(like cp-es, or eventually cobb's) will give great results.
I dont know why youre so scared of the other mods though...
With the AP you can just flash it back to stock... with an intake, it's simple to install and uninstall.
With the EMS it will probably run safer than without it... It drives smoother and better with the AP installed than just the stock ms3..
I'm sure you'll have morep ower with just the downpipe over the intake and ap.

I think you should reinstall your intake, and get the AP again.. It'll drive smoother, and a lot faster.
If you're willing to uninstall the dp in case of warranty work, the intake and AP will only take an extra 30 or sominutes...
Click to expand...

They said the same thing about the SRT-4.(guitar)

The downpipe is golden!(blowup)
 
Nachtsturm said:
They said the same thing about the SRT-4.(guitar)

The downpipe is golden!(blowup)
Click to expand...


Okay dude. Keep believing whatever you want. The fact of the matter is, that the catback for this car doesn't really add a thing, it's all in the restrictiveass downpipe. Anybody that knows anything about this car's exhaust will tell you the same thing I'm telling you. Even the OP.
 
You can do every mod in my sig and it's safe and hassle free. I had my first CEL yesterday, but it was because I didn't have the new/correct ic-to-turbo inlet hose yet and my manifold ate through the old ic-to-turbo inlet hose. Boost pressure dropping... Air whoosh evident... Engine-malfunction-malfunction-malfunction...

Fixed now, no CEL.
 
Once again I see everyone is focused on peak HP numbers...

A more free-flowing downpipe would let the turbo spool up faster, so even if peak HP numbers don't change much (since boost is still limited by the ECU) you would see a definite improvement in the driving experience.
 
The Only Problem I Have Is Smoking At Idle With A Down Pipe! I Gota Do A Catch Can!! But I Love The Sound With The Stock Cat Back!

THE SMOKINBG IS EVERY ONE AND A WHILE TOO LIKE OPNCE EVERY 3 DAYS. SO ITS NOT TO BAD JSUT STEP ON THE GAS MAKE A LIL BOOST AND IT STOPS IDK
 
Last edited:
bmman93 said:
The Only Problem I Have Is Smoking At Idle With A Down Pipe! I Gota Do A Catch Can!! But I Love The Sound With The Stock Cat Back!

THE SMOKINBG IS EVERY ONE AND A WHILE TOO LIKE OPNCE EVERY 3 DAYS. SO ITS NOT TO BAD JSUT STEP ON THE GAS MAKE A LIL BOOST AND IT STOPS IDK
Click to expand...

Im happy that I got 08 never heared that 08 had smoking problem...
 
bmman93 said:
The Only Problem I Have Is Smoking At Idle With A Down Pipe! I Gota Do A Catch Can!! But I Love The Sound With The Stock Cat Back!

THE SMOKINBG IS EVERY ONE AND A WHILE TOO LIKE OPNCE EVERY 3 DAYS. SO ITS NOT TO BAD JSUT STEP ON THE GAS MAKE A LIL BOOST AND IT STOPS IDK
Click to expand...

You should get a CBE...if you like the way the stocker sounds...you'll love the way a CBE will sound...
 
numbnuts22715 said:
Okay dude. Keep believing whatever you want. The fact of the matter is, that the catback for this car doesn't really add a thing, it's all in the restrictiveass downpipe. Anybody that knows anything about this car's exhaust will tell you the same thing I'm telling you. Even the OP.
Click to expand...

251hp/277tq stock, 270/292 current
Current Modifications- AEM CAI, TurboXS dp/rp, HKS Hi-Power cbe, Defi BF Amber boost gauge (vent), TRZ poly, MSD DashHawk

19hp for a TBE and CAI? I wonder how much of that power was from the intake. I just don't think exhaust are worth doing for the hassle they give you.

All I want to see is what these cars are running at the track trying to find times on these cars are lacking.
 
Were those dynos done with the same temp/humidity? and at the same dyno?


I know exactly what you mean, notmany people go to the track, and the guys that do are pretty much modded out of their assholes.
 
a good DP will help any turbo car that has a restrive DP. Infact a DP could actually make you have lower PEAK numbers, but the power under the curve will be MUCH better thus making the car faster. Peak numbers don;t mean much, Check the thread about 20 psi and look at my dyno graphs. One of the most hp per dollar mods for my SVO was a 3" elbow off the turbo instead of the stock 2.25". Plus it made the trq band flatter, thus raising hp numbers and making the car feel ALOT FASTER.

if you throw a CEL from a Dp then that means you increased the engines ability to flow air substantially and someting is no longer within its limits....thus requiring a tune.

First mods for an MS3..should be turbo/DP and a tuner........ then maybe rods next inline. :D
 
If you get a one piece dp like CPe (not sure if Cobbs will be one piece), it will be a PITA if you install it yourself. It is very difficult to fit it up there. Make sure your car is plenty high up in the air. I'm just speaking from experience. But the CPe is a very nice unit. Once up there, it ain't coming back out! haha. So if you got warranty work coming, make damn sure you set aside a whole day to take that b**** back out. Then maybe another whole day to try and fit back up the stock dp. That's a b**** to take out as well.

If you wanted simple and easy, Keep the cai, and add a race pipe. You'll have the best gains. And it'll be cheaper than a catted CPe dp alone. Plus swapping them in and out is very easy.
 
justa4banger said:
....
if you throw a CEL from a Dp then that means you increased the engines ability to flow air substantially and someting is no longer within its limits....thus requiring a tune....
Click to expand...

If I keep the restrictive intake, then that would seem to limit the flow and avoid CEL's from that. But what about the O2 sensor location? Isn't that another way you might throw a CEL? Seems like plenty of people are running the CPE without CELs even with a free-flowing intake, so I feel pretty good about it.
 
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