RE Suzuki

I've posted this up awhile ago regards to the bonez hf cat + RSR Single tip catback exhaust. After installing them, My boost dropped and exhaust was inconsistantly changing tone after WOT. And the primary turbo would not spool up above 0psi once the exhaust tone changes into LOUD DEEP tone after WOT.

I thought the hf cat was clogged so I gutted and used it as mp. but there it goes again. Same trouble I was faced with.

-Loud and deep exhaust note on cruise or even at idle.
-primary turbo at 0psi unless the rpm is over 4500rpm.

My question is, can a catback be "broken"?
With my stock cat and catback I had never experienced that type of problem. I didn't touch anything else besides the cat and catback. Now the cat is gutted, only thing can be causing this is the catback.
I bought it used from a forum member, "A'PEXi RX-7". He said it only has few thousand miles on it. And it did look clean.

Did I get ripped off?
Any comments from experience would be great. I'll try to ask him for my money back once the symptom that I'm experiencing is what the bad catback exhaust does.

DaleClark

iTrader: (55)

Dave Disney had a similar problem - if you have the loud deep tone and no low-end boost, the turbo control door is staying open. Time to look at your turbo control system.

Dale

RE Suzuki

Thanks Dale. Another thing that I noticed was that from the cat area, alot of loud exhaust sounds were comming out... bad gasket could cause this?

SWAT81

iTrader: (14)

actually I found out that for me it was a hose lose right behind the TB, it was unplugged and when I plugged it back in the car boosted fine and didn't sound as deep...

GoRacer

iTrader: (2)

You should have used new gaskets and tightened them well. The RSR could be baffled/chambered and slightly restrictive. The only quiet strait through exhaust is my new Buddy Club Spec IV i'm having special ordered from japan. Even the Racing Beat is chambered. Was your Bonez cat' old? ...You shouldn't have ruined it. Check the flapper on the exhaust manifold like Dave said or it could be vacuum hoses and silinoids. was it a coincidence that the problem arose at the same time as the exhaust install?

gfelber

Racing Beat exhausts for FDs are not chambered. I recall reading that the initial FD duals were, but haven't been for quite some time (> 6 years or so). I'm pretty sure RSR isn't either.

You have a turbo control/boost problem: not very likely that this is an exhaust problem. Think about it- why would a MORE restrictive exhaust cause your boost to drop (or be nonexistent) at lower RPMs, but allow boost above 4500? Check turbo control hoses/actuators and solenoid connections: http://www.autosportracetech.com/RX-...leshooting.htm

Gene

RE Suzuki

Everything was GREAT untill I changed the cat/catback.

I'll check those things you guys listed for me. Thanks!
After this is solved, I won't be touching my car for awhile!!
"More I touch, more things goes wrong"

RE Suzuki

What you've said above makes sense, but why would tone of exhaust sound/exhaust flow change? It sounds like theres a hole in my exhaust system and when that happens, the primary stays at 0psi.

DaleClark

iTrader: (55)

It could just be coincidence that you have a turbo control problem when you changed out the exhaust. Start checking the obvious trouble points - check valves, vacuum lines popped off, etc. You'd have to have a grapefruit up the exhaust to get 0 boost on the primary .

Dale

alberto_mg

It would change b/c there is a different amount of air being blown through. kinda like blowing through a floot hard vs softly.

saxyman990

DaleClark is right, definately a turbo control issue. It's just weird coincidence that they happened at the same time. I'd almost bet money that it's either a hose that popped off, or a bad solenoid valve. Start with the TCA (turbo control actuator) and associated lines/equipment. The TCA uses two solenoids to operate it (one pressure and one vacuum) and these are some of the most failure-prone valves under the hood. Check both of those, and all the hoses. My bet is that your problem lies in that area. Good luck

-Rob

RE Suzuki

Thanks guys, I'll check the valves. Again on the way to work, I tested my car and after WOT of 3 times, the exhaust got pretty darn loud and lost the primary. It's wierd how primary starts to work again, once I let the car sit for a little awhile. It's probably one of the valve working off and on. If the vaccum hose is off the problem would be constant.

I'm going back to the messy vaccum line diagram

saxyman990

Just a helpful hint while testing the solenoids: I've found that often the valves work as they should when cold, but then begin to fail when the car is at operating temperature. I would suggest heating the valves (using an oven, or a heat gun) and THEN testing them, to ensure that they work correctly at higher tempuratures.

-Rob

RE Suzuki

I'm just wondering. If the problem is the valve, CCV, etc....what and how is it causing the sound of exhaust to change drastically? The difference in sound is almost as much as with cat and without cat.

RE Suzuki

I was paying attention to sounds that are comming out from under the hood today on the way home. I've noticed following things.

When its performing nomal.
- I hear air comming out of the bov during crusing going about 80mph
-When I step on the gas pedal, I hear turbo spooling

When the primary is not boosting (only up to 0.2kg or 0.3kg) with loud exhaust noise.
-No air is comming out of the bov during crusing going about 80mph
-No turbo spooing up sound even if I step on the gas pedal.

What does this mean?
I checked the CCV actuator locacted near the Y-pipe but the exhaust note chaged back to nomal by the time I got home so when I checked the rod, it was in during idle and when I stopped the engine the rod was out. (nomal)

Any thoughts?

Speed of light

iTrader: (8)

I tend to agree with the posts that point to a turbo control problem, especially one related to the TCA and its' solenoids. No spool sure points to an exhaust side problem. I would carefully retrace everything related to turbo control just so you're sure of what you've got.

I think the relationship to the rest of the exhaust system (i.e., catback) is purely coincidental--it would have to be almost completely plugged to eliminate all boost. Did you install the DP at the same time? And don't you have an MBC that you were messing with recently? Hmmm... It seems as if there could be more to this story.

It's also possible that something could be going on with the prespool or wastegate actuators, but these normally require pressure to operate, so as long as they're still physically connected to the valves (flappers), I would not expect them to be a problem.

The TCA is normally returned to its closed (primary only) posistion by spring pressure after the (2) turbo control solenoids are de-energized and vent to the atmosphere. A common problem is the failure of the pressure side turbo control solenoid to vent properly (it sticks) and it will hold the TCA open, causing symptoms similar to what you have described. There are quite a few threads on the forum that discuss the problematic nature of this particular solenoid. The pressure side turbo control solenoid is the one located on the main solenoid rack, second or third back from the front. (The vacuum side is the one mounted on the ACV valve.)

As a test, you could disconnect the TCA valve (via the hoses) which should let it rest closed and at which time your primary boost should reappear consistently; if this is the culprit. (Note that your boost will go south above the 4500 rpm transition while it's disconnected.)

Hope this helps.

maxcooper

With everything working properly, you should notice a distinct change in the exhaust noise (it gets LOUD and MEAN ) when the second turbo comes online. It sounds like the flapper door for the second turbo is staying open when it shouldn't on your car, which makes the exhaust loud even at idle.

I think it is just a coincidence that you changed the cat and cat-back at the same time that this problem appeared.

On a side note, I always thought the reduction in exhaust noise below the sequential turbo transition is/was one of the coolest features of the stock turbo system. In primary-only mode, even moderately open exhausts are pretty livable, and then it screams when both turbos are working. In contrast, single turbo and non-sequential cars are pretty much loud all the time. I wish mine was quieter.

-Max

RE Suzuki

I was suspecting the Charge Control Actuator, but I should check the Turbo Control Actuator located on the bottom of the turbo first? How would I perform the test? I'm bit confuzed, from looking at the vaccum diagram...

RE Suzuki

^ I got it. I'll try that. I hope it's not hard to find to disconnect the hoses, since the symptom only occurs after few WOT on the freeway stretch and it last for about 10min... I'd have to quickly drive back, jack up the car, and locate the hoses, disconect it, jack it down, and drive...

RE Suzuki

Hey, I tried doing this but I can't get to it in time. My primary is online usually, and it stops working after WOT but not always. So I could not disconnect the hoses when the primary was down.

I'd like to try locating the solenoids which are related to TCA. I'm having some difficulty as to where they are located (which one?). Can I get little more help with to which solenoid you are speaking of?

Thanks alot!

Ripzta

Mine makes a totally different tone when shiftting above 4500 and drops the revs below 4500 in the next gear, no boost until 4500. The twins go into non-seq mode until revs drop below 3000 or revs above 4500. My mate drove my FD and thought it needed a tune but he doesn't understand how the seq twins work! Dunno if this will help!

RE Suzuki

Ripzta

Ah dun worry!

RE Suzuki

haha, anyways the problem is fixed. I changed back the straight pipe to stock main cat. Everything is functioning perfectly. I guess there was some issue with "too good of an airflow" with my turbo system.

Result:

dp + Bonez HF cat + RSR catback = primary boost problem
dp + Gutted HF cat + RSR catback = primary boost problem
dp + Stock cat + RSR catback = Perfect, no problem


Anyone want to buy my gutted Bonez HF cat to use it as mid-pipe?

cruiser

It doesnt make sense.