Maybe the CBE isn't just an expensive noisemaker after all
 

@Lex; mentioned a CBE is good for ~10hp when you're making 300, and ~20hp when you're making 400, so I was instantly interested in acquiring one for my BNR swap that is coming as soon as the V2's are ready. The consensus one would get around here is it's an overpriced kazoo worth a handful of HP at best.

Well here's my first Vdyno after installing a Speed Daddy (yes, pretty loud) versus my most recent log in similar temps. This is the same stretch of road I use for all of my logs. 310/360 was typical prior to the CBE.

http://i.imgur.com/CbaGZOd.png

I'm running a UR test pipe with this, stock DP.

Anyone else have some logs pre and post CBE? I want to bust this myth.

Pretty dramatic results, but then again, it's vDyno so I remain skeptical.

Would you mind posting the logs of the comparative runs?

Certainly

Calculated load and G/S flow tend to agree, and it was 10F cooler for the w/CBE run - but fuck'n A that's pretty substantial.

I think @NCspecV81; had some similarly loopy results that I dismissed on account of his mid-turbo upgrade, but I can't find the post.

I gained roughly 13whp with my Magnaflow (even more torque).

Initially I only gained about 5 HP. I was really bummed because I thought it would be more. Turns out that there's a pretty bad restriction on the connecting midpipe. Some brilliant person though it would be a good idea to put a 2.4 inch flange on a 3 inch exhaust. I cut that shit off and welded on a true 3" flange on and gained another 6-9 WHP and 1 psi of boost.

I have supporting logs showing the gains from each, if interested.

I would like to note that I don't have a downpipe so I think that's why I gained more than usual.

It definitely looks like it improved flow, but enough to cause a 30 hp jump, I'm not sure.

@ms3blackmica; @atvfreek; input?

Considering I expected next to nothing and bought this thing "accidentally" playing with the make an offer button on Ebay, I'll take it :tongue:

This might've been a fluke, but I did not deviate from my normal location or logging routine. I will be taking more for sure, I'm pretty retentive with keeping an eye on fuel pressures, AFRs, and KR.

I'm guilty myself of parroting what I'd heard about CBEs being nearly worthless, so if that isn't the case (at least for those with TPs instead of DPs) I'd like to correct that assumption.

http://www.mazdaspeedforums.org/foru...0/#post2304337

That was same day; same tune; same stretch of road. No denying there was a gain just from an axle back.

This was before and after my CNT catback with an OTS Stage 2 tune. Granted it's not CF 1.01, it's dynojet, but still showed gains.

You need to fix the throttle cells on the log to read 77 or 100. It'll fix that weirdness.

The fact that the stock exhaust makes more power at redline leads me to believe there is a logging anomaly. Not discounting that there are gains to be had with an exhaust but you would expect the graphs to show an increasing advantage as the rpms increase.

Agreed that is odd. Load is .07 higher and flowing 16 g/s more at 6k RPM in the CBE log but it's reading less power. I did get a Vdyno update today, but I opened some older logs and they looked the same, so I don't think there's been any change to the calculations.

Trimmed the logs and corrected throttle cells. Still looks pretty much the same though.

As for calculation changes, according to the release notes there were none.

I have no agenda here... I was just taking my precautionary weekly log. I have an appointment this Friday to neuter this noisy whore, clanking off my mid-brace on decel/engine braking. It's going to get another muffler or at least long resonator and some modification of the mid brace.

I just thought it was prudent to share - I've had consistent logs since the first time Justin gave me a map, and this blew away my previous results. If it does make even half of this power, the negative stigma about CBEs is pretty much wrong if you go with a CNT or Speed Daddy in the dollars for HP game.

Just to be clear, I'm not trying to prove you wrong, I'm trying to prove you right.

If I can in fact net ~30 hp from a CBE, I'll be buying one sooner than I thought.

I'd like to see more logs/graphs on the new setup to see if there's any appreciable variance.

I never thought you were - we're of like mind - show me the money. I'm apprehensive myself, but I've had far too many beverages for more logs. They will come.

Okay good, just didn't want you to get the wrong impression.

Also yes, WOT logging and cocktails don't mix well. Ask me how I know. :alcoholic:

I'll be waiting patiently, and hopefully some gurus will chime in during the meantime.

Yeah I've seen a lot of people eyeballing this thread but not commenting, which is fine. I don't want to sway anyone's perception off 1 log. But.. I've taken a lot of fucking logs in the same spot, so this was like WTF??? Perhaps premature, but the deviation from the norm was too far to ignore.

your butt would feel that type of power instantly. If you aren't then your VD isn't accurate.

I'd say the logging anomaly would be in the stock CBE log if anything, the CBE log graph looks like what you would expect from a DISI. The stock CBE log raises suddenly near redline, almost like a bump in the road or something. I've seen the same thing happen in my logs when I've hit random bumps that I did not hit in other logs, even on the same road. 30WHP may be excessive for a CBE, but if you consider that VD is really only accurate within +/-10-15WHP, it seems more realistic. The 10 degree temperature drop could also be responsible for some of those gains. If you told me a CBE with the stock downpipe was worth 10WHP, I'd believe it. Even though the stock DP is the main restriction, freeing up more flow behind it may help. The same reason we gain power from a racepipe, even when keeping the stock DP. The OEM MS6 exhaust must flow horribly at the Y connection, so I wouldn't be surprised to see gains like this on an MS6 as well. The piping is literally crumpled up and shit.

Smooth, mandrel bent piping and a larger overall diameter certainly aren't going to hurt performance. Also, butt dynos are horribly in accurate. I closed the gap on my spark plugs and I swear my car feels like it makes more power, but let's be honest, it probably doesn't... :D

May as well tag a couple more people with some tuning experience.

@rfinkle2; @snailD;

I've logged this same stretch of road nearly 100 times, and never seen this kind of 'anomaly". I wouldn't have bothered with a thread otherwise. It would be quite the fluke to show this sudden HP/TQ gain after CBE. The road is smooth and flat, and I've never posted boastful Vdynos before that look like max potential K04 #s - if anything they've been on the conservative side for a 25% corn Freek tune.

Just sharing what the Vdyno pooped out. I'm as surprised as anyone else.

NVH has a way of instantly wiping any credibility from the butt dyno - I've been in fully mounted cars that "feel" faster but don't hit the same 1/4 mile traps as my own car that felt very stock before the CBE. The butt dyno can be deceived.

your not going to gain that power from a catback exhaust. A few ponies sure but not 30. The stock catback log in the graph you posted definitely didn't look right, but honestly the HP on the the speed daddy exhaust looked pretty peaky and the TQ held longer than it probably should have. I know you cant go out and get another log with the stock exhaust but there is just no possible way with everything else staying the same. Both logs are tainted to me as far as looking for numbers go, I really just use VD to help my eyes so i dont go crazy just looking at numbers

True but we are not talking about 5-10 whp here. I don't care how much NVH your car might or might not have. That kinda power will be felt. If not logging, it would be apparent in day to day driving.

I want to agree with you this is ridiculous... but like I said, same spot, shitloads of WOT pulls in the same spot all showing 310/360. I take logs every time I fill up with a fresh tank of E and 93, Vdyno every time.

I'm just trying to determine if the negative stigma of the CBE being a ricer mod has any merit - and I know Lex, Freek, and Rfinkle2 have weighed in on this being not the case. Nowhere near this result, but still - it's not just a fart pipe if you get anywhere near these numbers.

Just get some new logs and see what comes out of it.

you will make more hp with a cbe, its been proven already. people just feel for the price of a 3inch cbe and the power you gain its not worth it. although i beg to differ, i think (especially on a ms6) you gain a good amount over stock (not 30 hp, lol.) most will gain you around 6-10 hp which is good if you can get a cbe at a decent price and of good quality.

I wasn't disagreeing at all, just stating that the upper end of that graph looks funky on the stock CBE pull. Our engines aren't exactly known for high RPM power, so the bump right at the top end doesn't look right. The speed daddy CBE run looks much closer to what I'd expect to see. It seems like more CBE gains have been popping up lately, so I would not be surprised if they really are making some power. I do want a CPE single exit to get rid of the POS stock MS6 exhaust, so I can't say I'd be mad about picking up some power for $600.

I just hope my ebay turbo back I will be getting here soon sees the sames results :)

This is the first platform, especially turbocharged platform that I've ever been involved with, that believes that cat back exhausts don't provide an increase in power.

It is actually somewhat odd to me that people believe that the intake side of turbocharging is that much more important than the exhaust side...

A catback was one of the first things I did for two reasons, performance and sound.

Corksport's results on their shop car were similar in terms of gains from their exhaust to Jgamb's.

I typically see better gains on this car from CBE's than downpipes tbh.

Couldn't agree more. I always see larger gains on the exhaust side than the intake side (once going beyond a Cobb Sri for example) i just did a tune on a BNR and couldn't crack 370. He added a cbe every log after that right around 400 and we had to lower wgdc dramatically to keep boost in check throughout the entire curve.

I see a lot of k04 cars that have no creep issues when catless whatsoever. Then they go with a CBE and boost creeps like crazy in the cold. That just shows how restrictive it actually is.

Sure you can make great power on The stock CBE. But definitely don't right it off as just a noise maker :)

I DONT KNOW WHAT TO BELIEVE ANYMORE!!!!

Funny you say this, just threw in a smaller gap plug in my girls car and it did feel faster.

Normally I'd write that off as well if I hadn't seen a local on the dyno make power with a smaller gap @Lex; was tunning on the rollers and besides the cool of time the pull and re gap nothing changed.

Actually on topic; I also noticed a loss albeit small when removing my obx cat back in favor of the stocker (just couldn't take the drone)

tapafuck

im reading this singing to myself "log, loglog log logs" .
I like my ricey cbe. 10 or 30 hp no matter to me bcuz I bought my ms3 w/ cs cbe already on it.an improvement none the less.

so now you gots more hp and sound like race car! yay!

Lol, head asplode. That's why I made the thread :biggthumpup:

This is definitely interesting. It seems like the consensus around here is that gains on a CBE is very minimal unless you push over the 300+whp mark, feel free to correct me if I'm wrong. The logs shows that there are gains such as an increase in boost and holding boost a lot better with a CBE and an additional 10 g/s as well as a slight increase in load. All of which can be used as an indicator that power is gain though a 30 hp increase with a CBE and only one set of logs to support it is hardly enough to sway people to spend money on a CBE for hp increase.

Just my two cents though, like i said feel free to correct me if anything I said is wrong.

Added my CBE the other week and as far as on a butt dyno I felt a small difference and I felt like I had a faster spool. I read and read the countless threads regarding gains from the exhaust and never found a definitive answer. I agree with rob, freeing up the exhaust side will yeild power. It seems like a pissing contest sometimes, is it worth the $700? To some no, but the noise and occasional afterfires make the driving experience a helluva lot better. To each their own.

Sorry if you guys have seen my post this in other threads... but more evidence.

http://www.corksport.com/images/deta...haust_Dyno.jpg

I'm just trying to help change the perception if it's accurate - people might move a $350-450 CBE a little further up their mod priorities if they think it has a decent HP/$ ratio and they want or can tolerate the noise.

I do agree the $750-900 options out there are extravagant, and the sticker shock drove me to Ebay.

My next question would be dfoes it matter if you cheap out on the exhaust, i.e. custom fab or speed daddy, or is it more beneficial to get a corksport or cpe exhaust that is better made

The numbers don't lie.

Hence my cbe purchase for xmas!

Surprised this hasn't been brought up already but something to consider.
MS6 vs Genwon vs Poo all have a different OEM catback set up. Additionally, all the aftermarket kits are not going to be the same nor perform the same.

I would be surprised if there were not at least some gains to be made with a new CBE, even thouhg I have been here for long enought to see the "noise maker" theory thrown out quite a bit.

I just think the magnitude of the gains are not that easy to quantify in general terms. It is going to depend on car (6 vs won vs pu) what other exhaust work is done (cats, etc.), what other mods in general, what tune, etc., etc.

Lol this post has forced me to post a WTB for the midpipe to complete a full turbo back exhaust >)

Random thought:

Wouldn't the gains be more from the fact there is less backpressure which means the turbo will spin a bit faster for an equal amount of WGDC which means more boost...so unless you're maxing out your WGDC, would not increasing WGDC across the board result in similar gains without any hard parts? Long and short, the gains are probably from the byproduct of increased boost and not from the exhaust itself.

Decreasing the back pressure cannot be replaced by just upping the WGDC.

Backpressure also affects your volumetric efficiency...more is less, less is more.

For those who can't afford the catback here's some results from a 3 inch axle back. I posted the link but here's the graph in this thread specifically. FUG your CF 1.01. Again, these were done SAME DAY on the SAME ROAD. Not just the Same road but down to the same point. I mark it by a Sign on the right.

Like the OP I gained 10g/s MAF; IDC went up 5 percent; calculated load went up .9; and 60-80mph went down 2 tenths of a second; And BAT's were 108 for red line and 109 for blue line. So pretty much identical.

http://i.imgur.com/0sBc4wL.jpg

I'm catless with the CNT and my car is not obnoxiously loud. Catback prices are a bit steep, that's why I went with the one I did. $350 shipped and I'm happy with the quality. I'm more upset about my dp/tp fitment. Corksport's tp does not like to fit to my m2. I think it's getting choked off there.

interesting. i just pulled the trigger on the UR CBE myself, so i've made a mental note to do some logs with my stock CBE.

unfortunately even if my results back this up, there will need to be an asterisk. in addition to the CBE, i'm putting on a new intake (CS for Aeros, need that CARB cert). but i can't imagine that would make a huge difference. so i'm curious to see what my gains will be from what will essentially be just a CBE.

like OP, i have a UR testpipe but OEM downpipe. i'm not on E yet (i know, i know), so i'm absolutely below 300 on this Cali 91 piss.

Or you could, you know, just do the catback first and do the intake later since it's by far easier of the two mods.

For science!

i thought about it, but i'm doing it all at once after i smog the car. tight for time. there isn't a big enough difference between the two intakes to really skew it that much, right? neither intake is 3" or bigger.

The big thing will be flashing a new map for the differences in maf calibration...which will skew your results.

I gained right at 20whp going from stock to CNT CBE when at the ~400whp level...


http://i77.photobucket.com/albums/j6...Ebothat69F.jpg


Thread here:

http://www.mazdaspeedforums.org/foru...xhaust-121759/

yeah, that was the other thing. i'll be getting a revised tune. i'll take the logs and post everything either way, still might give some insight for the sub 300whp people.

There are several variables to consider here. If the tune is not changed, a CBE will often result in higher boost so many of these dynos and pulls are not 100% consistent in measuring just the decrease in pumping losses. However the fact that you get a bit more boost is a legitimate gain from an exhaust.

Due to higher pressure differential across the turbo you will need a lot less WGDC for the same boost and it may even creep in the cold especially if catless.

When I went from a catted CPE downpipe and OEM CBE to a full 3" COBB CBE I saw around a 15whp difference around the 370-380whp mark - similar to what @cld12pk2go; saw.

It also looks like the gen1 catback is less restrictive than the gen2. The larger muffler on the gen2 probably plays a role.

So what youre saying is...just go axle back on the pu? :)


Sent while granny shiftin' and not double clutching like I should

I went axle back with no muffler

Visually the gen2 muffler is not nearly as direct flow wise as the gen1 and is the biggest restriction on the catback.

http://i39.tinypic.com/4ih8g5.jpg

http://i527.photobucket.com/albums/c...exhaust002.jpg

Same here.

I don't have logs to back up the before/after though.


Sent from tappin them titties

I listen to 3 people when it comes to mods and tunes. @atvfreek; @ms3blackmica; and @rfinkle2;
If they say its worth it to do it, i do it.

They may be fly by night tuners and builders, take no pride in their work, but shiiiiiiit, they put out some fast ass cars to date.

I hear rfinkle2 just parrots things he hears from his *real* tuner.

This is kind of what I was trying to hint at...that boost may creep up a bit with all other things unchanged other than a CBE and that can be what causes some of the power gains. Thanks Lex.

There is a reason that the boost creeps up. Yes, some gains may be attributable to higher boost levels, but that is exactly what you want. That shows you are increasing the pumping efficiency of the system overall.

I don't see how that is any different than increasing the efficiency of the turbo on the intake side with a less restrictive intake.

If you wanted to make the same power and work the turbo less, so be it, but a CBE is increasing the efficiency of the overall system. That is exactly what the point of any aftermarket part is.

i also saw 12hp 20 tq difference after catback

I haven't had the opportunity for another log to confirm / deny the gains from my OP, and it's slated for a bullet resonator addition tomorrow to hopefully curb the part throttle obnoxiousness. I *really* wish I had gone axleback or cut-out instead, as now I've got to modify the mid-brace due to the minor rattles.

I agree with Lex the OEM muffler is a beast and probably the culprit for impeding exhaust flow more than anything, and it's really the only part you need to streamline. Save the cash and get a quality axle back without the headaches IMO.

For the Pu*

Because Freektune. lol

BNR is updating his FB, you'll be getting plenty of mid-turbo action in short order. Curious though I see you doing engine builds - is that going to become a limited or full time service?

I know if my shit splodes or starts to get a lil tired on the compression some day, I'd prefer to get Freekbuilt to go with my Freektune.

Right now engine builds are kind of a limited/part time service. It's time consuming and a one man show, but I'm doing my best to keep up with the demand on that side of things.

So I wonder if I would see the same gains only doing something like this...

Definitely, imo.. but without a resonator, that shit will be LOUD.

With a muffler delete, you will see some gains. It LOOKS like the muffler is the biggest pressure accumulator in the exhaust system on the PU besides the cats.

Louder isn't always a bad thing lol but there would still be a resonator in the midpipe

You cant go wrong with any fly by night type guys.

Lookit me, built by a fly by night, tuned by fly by night types.


Im fucking fast, and im going to set more records this year. FBN FTMFW!

The main muffler will quiet things down much more than that resonator. Resonators typically reduce noise via sound reflection and mufflers via sound absorbtion with some kind of packing.

Any cat delete and no muffler with the resonator on this car may sound a little SRT-4ish.

Damn right BECAUSE FREEKTUNE!
honestly that was just changing from stock catback to 3inch straight pipe with no touch up tune (ill email you shortly tho)

I think I may try this out and see how it sounds with my catted CPE downpipe I have on

I thought it was weird seeing that the majority of the community excluded cat backs from their mod list on k04 applications. Me included, just went with the flow!

Even in the Honda community most members ran 3in cat backs for K series motors!

I have an appointment with an exhaust shop tomorrow, I am going 3in mandrel bent just havent decided what muffler (if any). I'll report back with my findings.

Let me know how much the shop charges to make the midpipe! ;)

They gave me an estimate over the phone, $380 for 3in mandrel bent cat back 3in flange, magna flow exhaust and 4.5in tips or $240 for straight piping + tips!

Wow, that's cheap as shit.

That's surely an apples/oranges comparison. The N/A K series motor STARTS making power where our turbocharged motor starts trailing off.

If I remember correctly, the 3 inch exhaust on a K20 is wasted unless it's connected to a decent race header. Those guys also use 3.5-4.0" intakes with good results, even on stock cams! The stock head just flows that well...

My example is about as pure as possible of showing the pumping loss differnce as it was a GTX3071 at 100% WGDC in both cases where the weak link was my stock BPV leaking...

Same ambient temp, same road, same tune, and same boost...

My results mirror exactly what you're seeing. The gen2 however looks like sees higher gains due to a more restrictive OE exhaust.

Like this?

Love hearing the turbine spool up and down but that must get tiring on a long drive.

its actually not that loud inside at all. I was expecting to hate it at highway cruising but one can actually live with it

That is nasty!!!


Sent while granny shiftin' and not double clutching like I should

Your neighbors must hate cold starts.

I just jizzed in my pants..

You dont know about "quiet that shit down at cold start" trick?

Sent from Pu

For a long time, I've been with Rob on this. This is the only platform I've ever seen that disregards such a simple, common, and effective upgrade so quickly. I believe a larger portion of it is that people just don't want to believe the gains partially because of cost involved as well as the varying results from different manufactures. If my wife wasn't driving the car it would most likely already have a catback as I believe the results are well worth it.

If I don't go full retard when I do the CBE, I'll make sure to do some comparison logs. I'll hopefully be taking the ko4 to it's absolute limits this year so the results should be quite telling.

I would imagine any 3 inch catback should show similar performance gains but the systems with better fit/finish from Cobb/UR/Corksport aren't cheap. For most of us just doing bolt-ons, that $$ is probably better spent elsewhere IMHO.

Every flow part adds "something" if well designed and installed properly. The bigger question is - what is the downside, is it worth it, and is there an alternative to arriving at the same power level? No one said the CBE does nothing.

yeah the argument has always been the money is better spent elsewhere.

exactly, most of the "dont get a catback" responses are in some noob intro thread where the guy had a honda before and thinks that dropping $850 on a catback is the best way to pickup 30 hp.

Exactly, and most of the time people inquiring about cat backs are stock or close to stock. Imo, yes there are other modifications that are more important but doesn't mean we should completely rule it out.

It's more about when you get it, thats going to determine how much gain you'll see.

In my case, I had relegated it to last on my list if ever because of the perception of minimal gains. If Rob says he often sees better gains from CBE than a DP, then it's time we pressure a vendor to make us an axle back at a tolerable price.

I searched the company that @NCspecV81; used and didn't find anything for Mazda at all, haven't called them and probably won't because my Speed Daddy goes under the knife in a couple hours.

I'm going to go ahead and say that yes, CBE prices are absurd. But, there are options if you want the performance without a graceful sound.....like Speed Daddy. You may have to use a mallet and torch gun to get it fit, but it'll produce probably the same results performance-wise as more expensive options.

Well if you travel over to the ST forum you can talk to OCDSpeed (Ollie) about the axleback. I know he has a jig for it since it was hanging on the underside of my car.

The real question is how much did you pay?