I finnally installed the Bonez HF cat and RS-R Single tip catback exhaust. They are both used and in good condition from looking at them.

Problem is I used to have 0.9kgs of max boost with Dp, stock cat, and stock catback. But now with DP, Bonez HF cat, and RSR single tip exhaust, my boost dropped to 0.8kgs.

I checked the inside with a flashlight before the installation but it was really clean. I can't imagin how my new set up could have more back pressure then before.

What could be that cause? Clogged cat? Can you give me some inputs?

Thanks!

 

That's odd. Less backpressure should increase your boost. Sure that cat isn't cloggy?

 

I know. It's very strange. I'm pretty sure it's not clogged. I checked it. It was all white, and it had no sign of burnt oil. I highly doubt it but could bad exhaust gaskets cause this?

 

That's a tough one. You sure you didn't touch anything else on the car save for the exhaust?

If you didn't touch anything else, probably the best route to proceed is swap the cat, if no change, try the cat-back.

Stands to reason - if you change something, then you have a boost problem, it's typically whatever you just messed with.

How are you turning your boost up - does the M2 ECU increase boost, or do you have a boost controller? Dunno if the boost controller would have spool issues with changing the exhaust out - I'd expect *more*, not less. But, it's a tricky one.

Dale

 

I do have manual boost controller. I did not touch the boost controller or anything else prior to the installation of hf cat and catback.

This is quite tricky if the cat or the catback has no problem. Maybe the manual boost controller does this when the exhaust set up changes?
If it is I wouldnt mind turning up the boost to 0.9kg with it, but if something is "worng" I'd like to figure this out.

Edit: I've heard that M2 ecu does not controll the boost. Correct me if I'm worng. I'll try resetting the ECU in that case.

 

Seems like you migth have gotten a slightly clogged cat

 

ouch. That's what I'm afraid of...

 

Anyother possibilities that may cause this problem?

*I doubt it, but the shop did not have the gasket so they re-use the old gasket...could that effect the max boost?

 

Well unless you accidently changed something on your boost controller I dont know how it would have gone down..if anything it should have gone up.

 

instal your efini y pipe fool

has to be that coupler on the stock crossover pipe

dont why did u buy it and not even instal it??? lol jk man

GL

 

How many miles on the "slightly-used" high-flow cat?

Dale's idea of swapping out the parts one at a time is a great way to troubleshoot.

 

rotoboy661: I'm gonna install it along with the motor thats comming in! Untill then, I'll look at it and do more "wipe wipe" to make it cleaner..haha

The forum member, Stevil told me it has about ~7,000 miles only. And visually, it is really clean.

 

Bolt the stock set-up back on and see what happens.

 

Ok. It seems like theres no other way but to put them back and see what happens.

 

I'll check them out tomorrow.
Thanks for the input as always guys!

 

. . .heres a nasy scary thought. Maybe a rat got into my hf cat since the cat was left in my garage for couple of months and they got cooked when I fired up my car after installing it....I hope thats not the cause of the low boost....lol

 

did u reset your ecu? not sure if that will help tho

 

i was thinking of that too, but no one has told me anything about it. I'm guessing m2 ecu does not controll the boost. Maybe it's worth the try. Thanks!

 

yea it should be worth a try, jus let us know if that helped or not

 

The M2 ECU controls the boost in the same manne as the stock ECU... which is to say not much at all. Boost is basically controlled by your system of solenoids and pills in your wastegate lines. You should run about 12psi boost with the M2 Ecu and no boost control. But since you have a manual boost controller then you now may adjust the boost with that.

 

A possibility that has not been mentioned so far is that the wastegate is now more efficient with the reduction in exhaust back pressure. Therefore, the balance point of the boost controller, which is essentially a feedforward servo, has been changed and it now has too much gain, causing overcompensation. Keep in mind that there is no reference to exhaust pressure to tell it conditions have changed--it is waiting for you to make that adjustment.

A 0.1kgs change in boost is not a lot, and not the kind of change I would expect to see if something is seriously wrong or broke such as a major intake or exhaust leak.

I also don't think throttle response would improve (as you report) if the cat were clogged. In fact, with a mildly clogged cat, the engine will go flat at the transition to the secondary [turbo] and the car will just not seem to go. So do you have this symptom? If not, I'd reset the boost controller and see how it responds. I suspect that you really don't have a problem, unless, of course, the three blind mice really did find their way into your HF CAT.

If you still think the CAT is clogged, send it to me and I will flow it in the lab and return it to you with the results... seriously.

 

Thank's Speed of light! Your comment made me feel better.

I just adjusted the boost to 0.9kgs and had little drive on the freeway. I happen to run into the rx8 and had a fun with him. The boost did hit 0.9kgs as adjusted everytime I WOT. The tone of the exhaust changed alittle after the drive. (the sound note got deeper, louder) but it turned back again in few min. It maybe that the cat is slightly clogged. I'm going to drive it for a week or so and see if that "something" will burn out...or see if theres inconsistancy with the throttle response.

edit: After the little drive, I did notice that the primary did not come on as it did before, (quick press on a pedal used to get me 0.5kg but that time it went only up to 0kg) and that went away when the exhaust tone changed back (quieter)

The car did run great after adjusting. It makes alot of difference between 0.8kgs to 0.9kgs as far as the "feel" of the accelaration.

 

Weird thou . Even if the M2 ECU does control the boost . It would not have changed just by a high flow cat and exhaust swap . And if it did his boost pressure would increase due to a lesser restrictive exhaust . The rat idea is kinda gross but anything can happen . There were some rat problems posted on the forum a long while back ... dead rat stuck in the dash and stuff .

Hope you get it sorted out soon

 

Thanks! I'm just going to run the car with manual boost controller re-adjusted to 0.9kgs and see what happens. I hope nothing happens!

 

Wow, I thought header wrap on the downpipe put off a smell... whew

Maybe you can take them off, using your hands to make a seal, blow air through each one. I've never tried it, but maybe it will show a clogged part.

Dave