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

[JgamB]

@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.



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.

[Agent_Orange]

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

Would you mind posting the logs of the comparative runs?

[JgamB]

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.

[JgamB]

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.

[[R]usty]

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.

[Agent_Orange]

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

@ms3blackmica; @atvfreek; input?

[JgamB]

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

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.

[NCspecV81]

Originally Posted by JgamB 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.

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.

[SilverMS307]

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.

[NCspecV81]

Originally Posted by SilverMS307 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.

[Easter Bunny]

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.

[JgamB]

Originally Posted by Easter Bunny 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.

[Agent_Orange]

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.

1.2.6 (beta) - Fixed a bug that caused Haltech logs from version 1.13+ to not read headers correctly - removed unnecessary code around the time converter logic

[JgamB]

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.

[Agent_Orange]

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.

[JgamB]

Originally Posted by Agent_Orange 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.

[Agent_Orange]

Originally Posted by JgamB 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.

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

[JgamB]

Originally Posted by Agent_Orange 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. 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.

[specvspeedfreak]

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

[sidekick]

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...

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

@rfinkle2; @snailD;

[JgamB]

Originally Posted by sidekick 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.

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.

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

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.

[snailD]

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

[specvspeedfreak]

Originally Posted by JgamB 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.

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.

[JgamB]

Originally Posted by snailD 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

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.

[specvspeedfreak]

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

[maddocx240]

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.

[sidekick]

Originally Posted by JgamB 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.

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.

[specvspeedfreak]

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

[rfinkle2]

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.

[atvfreek]

Originally Posted by rfinkle2 This is the first platform, especially turbocharged platform that I've ever been involved with, that believes that cat back exhaust 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

[maisonvi]

I DONT KNOW WHAT TO BELIEVE ANYMORE!!!!

[lilred]

Originally Posted by sidekick 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...

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

[spdtrux]

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!

[JgamB]

Originally Posted by maisonvi I DONT KNOW WHAT TO BELIEVE ANYMORE!!!!

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

[jdspeed3]

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.

[Erick13Speed3]

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.

[rfinkle2]

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

[JgamB]

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.

[timmcc02]

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

[MazdaBoy2.3]

Originally Posted by rfinkle2 Sorry if you guys have seen my post this in other threads... but more evidence.

The numbers don't lie.

Hence my cbe purchase for xmas!