Fmic And Exhuast

[gttiwanna]

Just wondering how many people with r34s have had boost issues after installing fmic and 3in exhuast ? And how'd they fix it

[Ben C34]

boost issues like what? Not enough/to much/erratic?

[milanr34]

not exactly the same as yours but I installed a fmic on mine and everything is fine. After about 4k rpm if you notice a drop in the power or it isnt building as fast as it should - one of the pipes isnt connected/tightened properly

exhaust will only play a role if its way too big or too small other then that its just noise if its all stock

[GTSBoy]

I have a Neo in an R32 with a good FMIC and 3" with good cat and dump. Just running off the wastegate with no boost control (didn't install the R34's solenoid) I could not get more than 6 psi. That's from a 5 psi actuator. Engine is in perfect health, etc etc etc, blah blah.

You shouldn't be getting too much boost (if that's your problem) from just an exhaust and FMIC. You might gain a psi or 2, and that might get you up to nearly 10psi, but the engine and ECU should be perfectly happy there.

[gttiwanna]

I get to much boost goes to near 1bar constantly and tyred everything boost leak tested aftermarket controllers I even ported they wastegate hole for the hell of it but still 1bar even of just the wastegate actuator so it shouldn't be over 10psi should it unless something's wrong hey only thing else I could think of is ecu has a malfunction ?

[gttiwanna]

It goes to 4-5 at .5 bar then builds up to 1bar at 6-7

[GTSBoy]

ECU malfunction cannot cause that much boost.

So, you're telling us that you have completely dismantled the whole turbo system trying to fix this problem? So you know that the wastegate is 100% free to move, not jammed in some way? Do you have a dodgy split dump pipe installed? Anything else that we should know about?

[scotty nm35]

Is the turbo stock? As above, it sounds like the wastegate isn't dumping enough exhaust. Are you sure the actuator is stock also?

[sleptema]

Unlikely but rooted vacuum line to the actuator? I had a mate melt a plastic 3 way connector, overboosted so much his manifolds glowed red hot.

[gttiwanna]

Has a split dump pipe but flap moves freely vac lines anit stuffed changed all of them

3times to make sure standard turbo standard wastegate and tyred another rb25 one to

Wastegate opens when I put the compresser to the vac line and don't loose any pressure

It's like the when the car is standard it boost to 5psi then 7psi

But after the mods does .5 bar to 1bar lol

[gttiwanna]

Yer pulled the turbo of had a look at everything and put back on

[GTSBoy]

OK, so next test. Disconnect the wastegate actuator rod from the gate lever arm. Tie the lever arm so that it is jammed 100% open. Take for a drive and report back. Expect it to take an age to come on boost, but if you drive it up hill in 3rd at about 100 and give it a bootfull it should come on.

[SargeRX8]

If you have an air compressor feed some air directly to the wastegate and set your compressor to push 5 7 10 12 psi in increments and just check each level of pressure make sure the wastegate actuator is opening correctly. Unless its internally seizing up it should still open at stock levels. Also I doubt your split dump is helping. I had a split dump for about a week. It was overboosting. When I tested my actuator you could hear the flap hitting the dump on the inside. It looks fine before you bolt it on but I found it was my issue.

[GTSBoy]

By contrast though, mine is fine and always has been.

[gttiwanna]

Yer drove it without the actuator on at all makes no boost till high rpm then just makes a lil

And my wastegate flap don't touch at all opens fully backwards in the split pipe so anit hitting anything and slowly tested it to

And opens fine That's what I mean I've tyred near everything

[#skyginer]

You can test wg spring using a large plastic syringe with a vac line attached to you wg actuator with a boost gauge t'd in. That will determine actuator psi.

Then check that you wg flap dosnt foul on you dump.

If its still a problem put a bleed tap on the vac line leading to your bov.

Check out autospeed.com.au for more info on that

[gttiwanna]

By contrast though, mine is fine and always has been.

So another words Mine should be ok on the mods

How about the boost sensor ? If that plays up would it do anything not the solinoid the sensor on the back firewall

[GTSBoy]

No. The boost sensor on the firewall (the ECU's sensor, not the gauge sensor) doesn't act until much higher boost levels. For example, when I was first tuning my boost controller (on this Neo engine) I had a problem with the pressure regulator I was using. It was basically jammed shut. So I had zero boost control. I saw 1.2bar a couple of times before working out what the problem was. In lower gears it would do this happily, with no savage boost cut type things going on. But if I tried it in 4th gear, the boost would shoot up there and there'd be a fairly savage cut. Once I got the regulator working properly I tried it a couple of times at nearly 1 bar and there was no savage cut (although I do get some R&R behaviour evident at high loads, that's a separate issue). The message here is that the boost sensor not only isn't used to set your boost level, it isn't actually used for anything very much at all. I have a suspicion that it might play a part in determining whether to fuel off the fuel map or the VE map, but that's a separate issue again.

[sleptema]

I broke my boost sensor (accidentally) off. Never noticed a difference ever. Was trying to figure out why for a long time haha.

No. The boost sensor on the firewall (the ECU's sensor, not the gauge sensor) doesn't act until much higher boost levels. For example, when I was first tuning my boost controller (on this Neo engine) I had a problem with the pressure regulator I was using. It was basically jammed shut. So I had zero boost control. I saw 1.2bar a couple of times before working out what the problem was. In lower gears it would do this happily, with no savage boost cut type things going on. But if I tried it in 4th gear, the boost would shoot up there and there'd be a fairly savage cut. Once I got the regulator working properly I tried it a couple of times at nearly 1 bar and there was no savage cut (although I do get some R&R behaviour evident at high loads, that's a separate issue). The message here is that the boost sensor not only isn't used to set your boost level, it isn't actually used for anything very much at all. I have a suspicion that it might play a part in determining whether to fuel off the fuel map or the VE map, but that's a separate issue again.

So another words Mine should be ok on the mods

How about the boost sensor ? If that plays up would it do anything not the solinoid the sensor on the back firewall

[gttiwanna]

You can test wg spring using a large plastic syringe with a vac line attached to you wg actuator with a boost gauge t'd in. That will determine actuator psi.

Then check that you wg flap dosnt foul on you dump.

If its still a problem put a bleed tap on the vac line leading to your bov.

Check out autospeed.com.au for more info on that

shouldnt have to if other r34s can run the same mods and not have a problem should just work dam it grrrrrrrrrr