Today I installed my Bonez midpipe in preparation to take it to an exhaust shop to weld the metal cat. I was curious to drive the car with the midpipe and I got all the experiences in just one night!

1. "hmm, it's not that loud"
after wot, "ahhhrgh my ears!!!"

2. "it doesn't stick so bad..."
after driving to girlfriends house... "damn I need that cat!"

3. "let's see if the boost gets crazy..."

with the boost controller off I get 8psi in the primary 10 spike in transition and creep to 13
(the stock cat is super restrictive! I never got any more that 9psi with the boost controller off with it)

with the boost controller on at 9psi I get 10psi in primary, spike to 12 in transition back down to 10 then creep again to 13

my question is, since I want to run 13 psi (m2 ecu), if I set my boost controller so I get 13 on the primary will the car overboost in transition and creep higher?

I'll put the metal cat in this coming week and I hope it helps keeping the boost steady but I just want to know what would probably happen

 

You answered your own question when you said "I get 8psi in the primary 10 spike in transition and creep to 13".

If you are creeping to 13, then you should leave the boost control alone so you don't creep past 13, don't try to raise your primary boost because then you will creep over 13, it seems like you will get an extra 3 psi over what ever you get for primary boost, I am having a similar problem.

I don't get boost creep (i think), but my boost goes much higher than primary boost after the 2nd turbo kicks in. I will get like 11 or 12 psi primary, then it goes up to 14 after transition, depending on my mbc. I can lower the boost so that my primary and secondary boost does not go any higher than 10, so I am not getting boost creep.

 

you guys need better boost controllers, tweak your current ones with your system better, or port your wastegates. Usually when it goes to liek 15 is when u need the wastegate ported so im guessing that your current boost controll setup could be improved on to give you the correct 13-11-13 pattern

 

neit_jnf, were you getting the same psi numbers before and after 4500 rpms, before installing the midpipe? I just installed a rx7store resonated midpipe yesterday, but I had my boost issue before that. I have been tweaking the boost controllers for a while now trying to figure out how to get my primary boost higher without making the secondary boost higher than primary, with no luck except I think when running about 10 psi. I am starting to think that maybe my old stock primary turbo is just maybe worn out and won't produce more than 12 psi, and that is in the higher gears, lower gears I see like about 9-11.

 

with the stock cat my boost was solid to whatever I set the boost controller. I have a KS EBSIII which controls the stock boost control setup.

with the EBS off I would get solid 8psi with a slight 8.5 or 9 spike in transition, barely noticeable even on the dyno

when I set it for 13.5 it would be solid 13.5-11ish-13.5

I'm not creeping past 13.5 at redline with the midpipe, and the boost controller tests I did with it off or on didn't change that.

When I set it to 9 psi, I got solid 10 until transition, a spike to 12, back down to 10 then slowly creeping to 13ish

If I'm not creeping past 13, I may be able to have a solid 13-11-13 pattern again but my concern is the possible transition spike

But this is temporary as I'm going to have a metal cat welded in the midpipe and that'll probably give just enough back pressure to keep boost under control.

 

The boost controller will not affect creep. The boost controller will ensure boost is well controlled to the set values (or less is you are not yet generating enough exhaust to spin the turbos hard enough), until the waste gate is overloaded. The boost creep is due to the wastegate being overloaded - there is more gas to flow than it can handle to lower boost. When you put on the high flow metallic cat it may solve the problem, as it will lower restiction after the wastegate, and you -may- get a little more flow through it. I suspect you will have to port the wastegate though. Some do, some don't. When I had my midpipe on I didn't have boost creep. I ran at 10 psi and later at 12 without boost creep. The higher the boost, the greater the chance of boost creep as the higher the boost the more gas there is to flow.

Just to be sure we are on the same page here, boost creep is seen as a slow rise in boost with RPM. It usually starts around 5-6000 RPM, where the wastegate becomes overwhelmed by the amount of exhaust gas you are generating. Below the point where the wastegate is overloaded, there is no effect.

 

I could be wrong but I think you can raise the primary turbo boost to equall the secondry by adjusting a rod in the turbo but cant remember what its called.

I think you can control spike by putting a restrictor in the pipe from the pre control actuator.

 

Ok so I found a shop that makes custom exhaust systems mostly for american muscle cars and I was impressed with his work so I set up an appointment. I told him what I wanted (install cat, resonator and air pipe before the cat) but I couldn't stay because of work so I trusted him with my baby

After work, and $100 later, I go to pick her up. I wasn't expecting too much of a change in sound except slightly lower volume. I was shocked when I started her... The volume got LOWER than with the stock cat!!!!!! And a deeper tone too!! Damn, I so happy with it! It's just amazing what a difference it makes.

It still stinks a little while the cat heats up, then the stink is gone. Maybe the cat needs a break-in period to work better, or the 200-cell doesn't provide enought surface area for cleaning the exhaust, I don't know. I only drove it a few miles so I haven't had time to test the boost pattern but I'm just ecstatic about the new quietness of my car!! You could never tell it has a full 3" system, it's *almost* like stock but with a deeper, better sound to it.

I'm going to the strip tonight, I'll let you know about the boost pattern and performance increase (if any) with my new setup. I'll also take some pics of it and post them later...

 

the pics and more info will be in another thread...