[Taskmaster]

Part of me wishes I had my own fabrication shop...
anyhow, I don't know how many of you venture outside of E90 post, but there are a few forums I frequent, including a 350/370Z forum. I don't know why, but @kgolf31 gave me an idea.

Well "test pipes" are just secondaries deleted and replaced with a straight through pipe, however some genius (seriously) decided that adding helmholtz resonator huge gains could be made on top of normal test pipes/high flow catalyst.





Copied from my350z:

Originally Posted by Hydrazine

The dyno plot at the bottom (thin red line) is the baseline dyno of the HKS exhaust with Berk HFC's and a full tune by Church Auto.

The Green line is the post dyno of the ART pipes with the Shockwave exhaust on the same HKS&Berk tune.

The red line on the top is a retune of the cams on the ART pipes and Motordyne exhaust.

This plot is indicating 2 things.

1) The ART pipes and Motordyne exhaust makes gains over the HKS and Berk exhaust configuration.

2) When the cams are retuned to the ART pipes, even more gains can be made. And the gains are quite substantial.

[Taskmaster]

Here is what I learned
1. Yes there is power to be gained by removing the secondaries

2. Mocking something like this would require some type of formula or trial and error

3. Secondary catalyst removals NEED a cam timimg retune!

I think #3 IS A HUGE deal too. People who have secondaries will need a different tune than those without. I started to believe thia was the case when pouring over the dynos from cars with headers and cars with secondaries deleted. There was a guy with ESS's tune that deleted his, but ESS didn't retune the car, as they believed the A/f ratio was fine - and it was. However, the flow/scavenging effects had been altered, and more power could have been gained by adjusting camtiming to compensate.

Found the thread
http://www.e90post.com/forums/showthread.php?t=983661

[Taskmaster]

My train of though would be

1. Normal tune
1a- secondaries deleted
1b- headers
1c- headers and secondaries

2. 3 stage manifold/intake tune
2a -secondaries deleted
2b -headers
2c- headers and secondaries

[JDane07]

I've always wondered if I should attempt to get my e90 retuned since going with supersprint midpipes. Might have to look into it.

And welcome back Axiom

[Taskmaster]

Thanks man!

I have to do some more research, but looks potentially promising. I will point out that the Z/G don't have the primaries in the manifold like we do, so I'm not sure how/if that has an impact.

[Mike.]

interesting..

[xander_e90]

Pm's

[Kgolf31]

I think 100 cell hi-flow cats should be an option as well. Expensive test for that, but it's required for me to maintain class legality.

I really like the thought process through this though

[mlifxs]

subscribed

[Mike.]

Originally Posted by mlifxs

subscribed

right up your alley

[Taskmaster]

Originally Posted by Kgolf31

I think 100 cell hi-flow cats should be an option as well. Expensive test for that, but it's required for me to maintain class legality.

I really like the thought process through this though

If it were me, I would be looking to convert to a full single with 1 in line high flow catalyst. Save weight, and free up a little bit of power.

[mlifxs]

Originally Posted by Mike.

right up your alley

yeah, if I get back in this game, perhaps this would suggest:

3 stage + secondary delete + re-tune?

Thinking the 3 stage requires a re-tune anyhow. Secondary delete droning would kill the idea for me though...would like to think it wouldn't (drone).

[Mike.]

Just flick in a resonator!!

[SDemetris]

I did a seconady cat delete by taking it to an exhause shop and having them bend/weld in some new pipes. Cost me $140 and i sold the used cats for $50 each to a scrap yard... however, if i were to do it again, i would do what i did on my e30 to remove the cat.. take the exhaust section off the car, bolt the flanges on either side to a wooden jig, cut out the cat.. after that i had to cut some straight and mandrel bent tubes and have a friend weld them in, but that was easy since the pipes were already cut and put in exactly the right place

[SDemetris]

Also, no it doesnt drone at all unless im at like 900 rpm going up a hill

[Taskmaster]

I know there is more power to be gained from the exhaust and exhaust tuning, I just need to prove it. A 'Race Exhaust' with a tuned Y pipe (I'm thinking the Y pipe should be placed closer to the end of the transmission) and a good highflow cat/straight pipe into a resonator/muffler will be around 10-15whp easy.

Active Auto's exhaust is an actual muffler delete with a hemoltz resonator to cancel out a lot of drone, and is good for about 5whp+

There is a dyno of a member with a Z4 with a muffler delete who gained..you guessed it, 5whp.

Deleting secondaries, with a stock muffler and no tuning is good for 5whp+ and while mods are not additive per say, it does add up. Active had a 3 inch race exhaust for the E36 that was good for some extra power as well...

[Taskmaster]

As you can tell, I don't sleep - but I feel like I getting real close to some answers here.

Exhaust cam tuning.
Y pipe placement.

I'll probably have some dynos here in a bit...if I don't finally fall alseep.

[Taskmaster]

http://forum.e46fanatics.com/showthr...857&highlight=

I'm using my phone to post everything lately, as my computer is *still* in pieces, so I'm not poating the graph directly for you. But the takeaway from this is exhaust cam tuning CAN make a big difference, but that is determined by how good/bad your exhaust syst flow is.

Here is a statement on Tony from Motordyne about his ART pipes

http://my350z.com/forum/intake-exhau...art-pipes.html

From other posts I've read from Hoveringuy, he installed headers on his car and the gains were almoat non existent, untill he tuned the car - in the link I posted above, he also explains how the exhaust cam can have an impact on the DISA transitions as well. Cool stuff.

More torque, smoother powerband, and more power could soon be ours, how to get it done is the real issue.

[mlifxs]

Originally Posted by TheAxiom

As you can tell, I don't sleep - but I feel like I getting real close to some answers here.

Exhaust cam tuning.
Y pipe placement.

I'll probably have some dynos here in a bit...if I don't finally fall alseep.

Aliens (your avatar) never sleep.

[hassmaschine]

if I could ever get anywhere with the program disassembly, it would be really cool to use the sport button input to control an electric exhaust cutout (via the exhaust flap output). Potentially it could also switch the cam timing & AFR maps. Who knows.. one project at a time.

BTW, I know Hoveringuy in person. We did a dyno day together several years ago, he's primarily the reason I got interested in the N52. We were both playing with cam timing, the only difference is he could do his with his laptop, and I had to use wrenches...

[Taskmaster]

Originally Posted by hassmaschine

if I could ever get anywhere with the program disassembly, it would be really cool to use the sport button input to control an electric exhaust cutout (via the exhaust flap output). Potentially it could also switch the cam timing & AFR maps. Who knows.. one project at a time.

BTW, I know Hoveringuy in person. We did a dyno day together several years ago, he's primarily the reason I got interested in the N52. We were both playing with cam timing, the only difference is he could do his with his laptop, and I had to use wrenches...

Glad you're here, I was going to tag you in a post, but it doesn't work from mobile. I'm at my work computer now, so I can do whatever.

Am I right though?

[hassmaschine]

yes I think you could do it but it would probably be expensive to get it worked out to the right frequency. when people test merge placement they use those spring loaded test pieces so they can swap them around for different pipe lengths to move it around, that might be easier but it would still be expensive.