kmook

I made a post earlier about my friend that has a turbo syclone (I know not an fbody but the turbo principles should be the same). Since a week ago, the car only makes 10psi instead of the normal 15psi that it always did. I hooked up datamaster to it and noticed he was getting a ton of knock retard, and thought that the retard would make the car produce less power making less exhaust gas therefore making less boost. But sleeperz28 advised otherwise (Thanks!) He replaced a few ignition parts and the retard has gone away pretty much. But he is still only making 10psi boost still.

We bypassed the solenoid for the wastegate and then only made 8psi. So does that mean that the wastegate is set to open at 8psi, and the solenoid keeps it closed until the predetermined setting via the electronic controller (say 15psi)? If that is the case, when the solenoid is hooked up and the controller set to 15psi, and we only see 10psi, does that mean the solenoid or controller is not working correctly? Or is there a completely different problem that we might have?

I am not experienced or knowledgeable at all in the turbo realm. So ANY help would be appreciated!

Chrisbequick

Interesting. What kind of boost controller are you using? Does it have a "fuzzy logic" feature?

What kind of turbo and exhaust? The stock wastegate on those trucks is undersized, but obviously that tends to lead to an overboost condition on trucks with good exhaust.

-Chris

kmook

He said it is an "Ultimate" controller and doesnt have a fuzzy logic feature. As far as the turbo he said it is a mitsubishi tdo6 16g with open exhaust.

kmook

Update:
We tried removing the orange flex inlet hose that was on the car as i know our supercharged fbodies with it sometimes have the problem of them collapsing under heavy load. But that made no diffrence.

We then tried connecting a vacuum line from the inlet side of the turbo to the accuator for the wastegate instead of a line from the manifold which sees boost. And that made no diffrence.

Geoff Chadwick

He's using a 16G??? Granted it'd a Td06 housing... Those turbos on a DSM can push out 400hp... maybe a little more... But honestly for a 4.3L engine I dont know how much he can expect. I believe that turbo puts out 550cfm or so (without checking my old books from DSM days) which isnt anything dramatic.

The stock wastegate is set to 8psi no matter what, so if you hook a vaccume line to the compressor outlet or intake manifold and then to the wastegate, it will push open at 8psi.

How long has he had this turbo on? I'm kinda nervous you say he's pushing 15psi, as he's probably pushing the turbo toward the top of it's envelope if not starting to go out of it's efficiency range. A 2L DSM would push 20psi and not be too bad, 25psi would be pushing the turbo past it's limit... but this engine is also twice the displacement...

I dont think he'd be pushing the wastegate open with exhaust flow, but there is a chance that the flow is so high that it's forcing the wastegate open. If his car has good tuning and fuel, you can try a really bad idea, but I wouldnt reccomend it unless you know it could handle a 18-20psi spike of really hot air. Plug the line that goes to the wastegate, and then leave the wastegate un-attached. Without that the wastegate shouldnt open, so it'd spool all on it's own - which means go through a low gear at partial throttle, trying to get it to spool slowly. As soon as it hits 12psi or so, get off it, and quickly. But if it wont go past 8psi or so, the exhaust is pushing the wastegate open, or the turbo is blown.

But it could be something else...

My real thing to check is I'm tempted to say he might have a leak. Get some strong *** clamps and something to seal over the intake of the compressor (like a silicone cap for example) and have fun. Seal the compressor inlet, and then get an air nozzle to your air compressor in the garage, and regulate the line to like 20psi. Plumb it to the intake with a vaccume line, and pressurize. You'll hear it through the engine through the Throttle body (you may want to block the throttle open if it's too loud through the idle air opening), and it'll go past open valves, and then through the PCV valve... but listen around for other hissing. That might be a problem, and hunting boost leaks is a POS and often time consuming.

It's most likely one of those, or the boost controller is shot.

What brand/model of controller is he using?

Turbo6

If the wastegate actuator is anything like the setup on the turbo buicks and it is adjustable via threading in the actuator arm closer to the actuator diaphragm/spring, then that will limit the total amount the wastegate can open even with only an 8# spring and will increase maximum boost.

Is spoolup slower than normal or about right? It could be a misalignment of the wastegate puck on the wastegate opening if its spooling slow as well.

Geoff Chadwick

The rod *could* be an issue, but alignment is very hard to do with the mitsu flappers. I've only seen one wastegate that was adjusted wrong on a mitsu turbo, and that took a real idiot to do... But it could be possible

(gotta love internal wastegates)

cvcsmkr

Ken's friend Chad here.
with his tempermental Syclone.

Yes it is a tdo6-16g Turbo, it is stock. Some guys are running the turbo upwards 19lbs. But that is its limit.
And yes the wastegate is undersized but it was working fine before so i dont think sizing is an issue.
The lag is nothing more than normal.
I dont actually have a boost controller.
There is a solenoid on the wastegate preventing the wastegate from seeing the pressure. I have a chip in the cab which allows me to change the amount of max boost. I guess it just operates the solenoid.

Chadwick: I think we are on the same track. Like ken said, We did do that. by hooking a tube from wastegate actutor to intake filter so it saw actual vaccum even when motor is under boost. I couldn't get over 10 psi. No retard whatsoever.
Yes the other thing you said. i found link on syty board to use a bicycle tire tube and clamp one end shut and wrap the other end on to turbo. then pressurize for leaks. So i will be trying that today

turbo6: i am not sure about that but i will look into

I have come down to 3 things:
1. Turbo is gone
2. There are air leaks
3. Wastegate puck is flopping around

Any other recommendations is greatly appreciated.

One thing which confused me.
I am still new to this turbo tuning thing.
But i have a base fuel Press of 50 getting 2-3* of retard, 920 o2 Mv. I increase my base Fuel press to 52 the u get 16* of retard and 950 o2 mv. This doesn't make sense to me. maybe this can explain whats going on with turbo.

Geoff Chadwick

so you richened conditions and got more retard, right? Well, in a turbo car, tuning is really irritating. Aside from if your stoich is wrong you can get detonation one way, it can also really have fun with your exhaust gas temp and raise it through the roof. I'm guessing that isnt your direct problem though, just doesnt seem to make sense to have that much of a problem from running a tad richer...

Now I'm going to go out on a limb and compare a mitsu turbo and boost solenoid on a 1g DSM, just because I *think* they might be the same setup.

The outlet of the compressor housing has a vaccume line that goes to a solenoid, and then to the wastegate. The solenoid never cuts flow totally, rather it can divert part of the air back to the intake (pre-compressor) Or divert none at all. If it diverts none, the turbo spools to 8psi and the wastegate opens. If the solenoid bypasses air, you might see 10-12psi.

Why is the solenoid there? The solenoid is there to be ECU controlled. If the ECU sees a problem (like massive knock, timing errors, fuel errors, the MAF values get too high) it will freak out and activate the solenoid, limiting boost to 8psi incase there is a problem to save the engine. It's a good thing from the factory, but in all honesty, remove it from the vaccume lines and bypass it. (leave it plugged in - it will probably throw a CE light if you dont). Then put in a boost controller. You'll loose that "safety" feature but you want more stable and predictable control of the wastegate.

I'm guessing the TyCy is the same way, and that the solenoid doesnt totally stop flow, which means if the solenoid dies (which happens) it wont let you run more then 8psi (But the mitsu solenoid, when removed throws a CE light, but if it dies, it wont throw any indication of a problem... how odd is that?)

Now you say you hooked the wastegate straight to the intake before the compressor inlet to get vaccume, and you STILL arent pulling more then 8psi? If that's true, either the turbo is shot, the wastegate isnt working right, or you've got leaks. Was there a specific thing that was done before this happened?

cvcsmkr

well great minds do think alike.
chadwick: i think i might need to get a EGT gauge?
to throw another wrench in, i was able to get a hold of the previous owner and the solenoid had been replaced. he was on the way to dyno and he could only make 6psi. thus the replacing the solenoid. the way this solenoid is plumbed is the turbo compressed side to solenoid inlet then solenoid outlet to wastegate actuator.
turbo-----solenoid------Wastegate actuator


From what i think your saying (1g) is that solenoid has a like 3-way valve were it can send to wastegate or plumb back to intake like a bypass valve? is that correct?

The chip i have can be adjusted from in the cab almost like a electronic boost controller. I have different maps with different fuel and timing and boost curves. i think it controls boost thru that solenoid. i am going to look in to that! That would be the only reason i wouldn't go to manual boost controller.
Pic of my chip

Also with my fuel pressure.
I think i might be a little rich as it is @ a base 0f 50
Would increasing the fuel and sending way to much in cause knock and the ecu to retard?
maybe i am at the line of stoich and gas pouring out my exhaust?
one extreme to the other. to lean=possible knock
could too rich=possible knock?

Was there a specific thing that was done before this happened?
Not really. But i dont drive the truck that much and i dont WOT everytime i drive it? so i could have had this problem a month ago and not have known it.

By the way, since you have a dsm and know? what kind of options to upgrade to turbo to, would you say?
i was thinking a 20g wheel and like a 14cm2 housing.
do you guys run anything that big on yours?
if so you know where i could get it?

Geoff Chadwick

The DSM is wired the same as yours is now electrically, but vacume wise:

Compressor Outlet-----Solenoid----Wastegate
|__intake manifold

The solenoid just lets some air pass, it never completly cuts it. If there is a "one in, one out" to the solenoid, that's a problem.

If you're running really high intake temps and you run rich you can detonate just as if you run lean. Is this your problem? I doubt it. Do you need an EGT? Probably not. I personally loved it plumbed into the last cylinder in line (most lean) and noticed temps. If it broke 1600deg F you knew you most likely just broke something, but tried to keep it close to there.

Good thing about the 16g turbos is they still are internal wastegates. Anything above and you need to go External, which is better anyway. A 20g would be the next step (ignore an 18g) but I dont know if that'd be the right turbo for you. Good place to check is www.forcedperformance.com - they do a LOT of DSM turbo work, and know the compressor maps like the back of their hand so to speak. They can help you pick something out.

On DSM's - a 20g is used, but a lot of people stop at a 16g. 350wheel hp isnt slow, and anything beyond in a dsm means a lot of supporting mods and an external wastegate.

kmook

Good call. Chad bought a bycicle tire tube and used that to check for leaks. Low and behold a clamp on one of the pipes going to the intercooler had loosend to where under boost it was pulling off and leaking. After tightening that up he is back to normal.
Thanks for the help bud.

Geoff Chadwick

That must be one fast truck! Good to hear it's boosting well again!

KLUCKS-SS

Hey, if you havent yet check out http://syty.net and you can get Ultimate chip help and any other SyTy help that you need!

Brian

kmook

Yep, he is on that board. He had tried posting it there too.