Ok, so I thought that my boost controller was acting up because I wasn't getting any kind of "push" when my 2nd turbos kicked in. I drove to Rotary Extreme and talked to Chuck and after redlining in 2nd gear down a road, he saw that when the 2nd turbo kicks in, my boost gauge shows around .4bar. So he said that I should check one of the clamps and replace it anyways because they split. The second thing was to check the pipe going into the IC to make sure there was no kind of cracks because he said they have a tendency to crack. Then he told me that after checking those, that if I don't see anything wrong that it could be my turbo.

Now here is the story. A couple weeks ago, I was getting on the freeway and I was going on my 2nd turbo and I heard a pop and then whooshing sound and my boost died down. Then a week later, again I was driving on the freeway just crusing and I heard something loud hit my car. Now it sounded as if it was in my engine on the passenger side and then it hit something on the side or under the car. I don't know if something from the engine bay came out and dropped down or if I just ran over something.

From everyones experience what do you guys think it is? I'm hoping it's just a clamp, but we'll see. So in short, I believe my first turbo is fine, it goes to around .5-.6bar (because I have my boost controller cut boost down when it reaches 9.5psi) and then when second turbo kicks in, it drops and barelly stays above vaccum.

 

When I had this problem it was a tear in the coupler on the top of the Y-pipe.... Full boost with primary and about 4 psi with secondary. Are you hearing any boost leaks when your secondary turbo kicks in??

 

Where is the coupler located? I have never worked on this or any car before so I am new to everything. It might sound as though there is a boost leak when the secondary turbo kicks in, I just hear like a "whishing" sound and no push at all as my rpm's climb.

 

Bump for help!

 

its on the passenger side. standing in front of the car follow the crossover piping back and to your left. it will then curve downward, and there is your coupler between the crossover and y-pipe.

i have this same problem, my crossoverpipe pops loose... get a efini pipe will fix this problem. gl on any others there may be..

 

I think that's the coupler Chuck was talking about. He said just to replace that (said it should be $10-$15 the most) and see if it fixes it. Are we talking about the same thing? It's like a rubber seal right?

 

mid-day bump

 

Have you lifted your hood yet to look for anything?

1) It could be something picked up while driving
2) It could be a damaged coupler, clamp, etc.
3) It could be that something got caught in the belt and made a big noise.

Lift the hood and start inspecting.

Dave

 

Yeah when I brought it to Rotary Extreme Chuck and I took a look, he said that the first thing is to replace one of the clamps because it has a tendency to split, then he also said to check the piping going into the IC, we looked at it a little and saw that it had a forming of a crack.

I think I'm going to bring it to Paul and Rotorsport and have him check it out and diagnose everything.

 

Bump

When I get full boost in primary but very little (2-3psi) in secondary turbo, does that automatically mean my secondary turbo is busted? Because if there was a leak, wouldn't that mean that I wouldn't get full boost in primary turbo?

 

http://www.autosportracetech.com/RX-...leshooting.htm

 

I tend to believe that is true. However, enough people have found a boost leak to be the cause of this kind of boost pattern that it's silly to not consider it first.

The next simple/easy/important thing to do is test or replace the check valves. A bad check valve leading to the pressure tank will often make the secondary laggy or low.

But honestly, since you're taking it to shops to get the diagnostics and work done, it's a waste of time to talk about it here. I like to try and help people with their turbo problems, but it's a complicated enough process that it works only if the other person goes and does some DIY work under the hood, then reports the results. Then I suggest the next test or thing, and it repeats until the problem is solved.

Dave

 

Just dropped the car off at Rotorsport, he's going to diagnose it and let me know what he thinks the problem is. I'll let you know what he said

 

Ugh, so got a call from Paul from RotorSport and he is going to keep the car over night, it isn't something that was small like a clamp or hose. I really really hope it isn't a blown turbo Anyone else think they know what could be the problem?

 

Blown turbos don't cause this. A bad solenoid, loose vacuum hose, bad check valve, etc will probably be the cause here. The trick is figuring out which one.

Dave

 

Alright, so average cost to repair one of those would be what?

 

also to add to this post, may i have some help with my turbo its almost the same but its oppisite, my primary is boosting like4-5 bars it says on the boost gauge then 10-12 when secondary kicks in, is this normal?

 

o yeah its still sequitial

 

Solenoids are about $60/ea, and the mechanic may recommend replacing between 1 and 4 of them. He may also suggest the vacuum hose replacement if that hasn't been done already. That hose runs around $120. But the parts don't add up as quick as the labor.

A very knowledgeable mechanic might find the problem in an hour or two.

Labor is the beast - just to replace a solenoid on the rack, you need to remove the TB, UIM, and coils. Changing all the hoses adds a few hours.

So the bill could vary widely, which is why i DIY it. It takes some patience and time, but you only pay for parts, and can replace other important things while 'in there'. Often the FPD and injectors get changed when doing these jobs under the UIM.

Dave

 

Check the items under "T" in the FAQ thread:
https://www.rx7club.com/forum/showthread.php?t=68640

Your gauge is probably reading in psi, not bar. (1 bar = 14.5 psi) Do the on-road boost test in 3rd gear, full throttle, starting at 35mph. You should see 10psi between 3000-4500rpm, then 8psi for a moment as it passes 4500, and 10psi above that. It may fall off a little toward 8psi above 6500rpm. 12psi indicates overboost.

Dave

 

ive done it, all it reads between 3500-4500 is 6 then 4500-7000 it reads 10

 

also the boost gauge is this one, not sure if it reads PSI or just by bars

 

That gauge is in PSI on the pressure side, and inHg on the vacuum side.

As for your boost issue, it would seem that one of the valves that should be shut during primary turbo operation (turbo control or charge control) is leaking some of the primary boost into the secondary. The KOKO test should be ideal for deciding if one of these is the problem: you'll find it described at www.fd3s.net/boost_test.html

Dave

 

if i had a un nessicary T would that mess up my boost pattern, i got 1side goin to the manifold, one into the CRV, and the other caped...this is for primary turbo

 

Actually it's the ABV that gets it's line from the manifold. I assume you meant ABV.

The tee should be harmless, assuming it is not leaking.

Dave