Hmmmm. In the two cases you bring up, how is boost being controlled? I mean, is it MBC, EBC, Hybrid, ECU/BCS, or whatever. Also, are we talking stock actuators, or aftermarket WGA's?

 

Both using MBCs and both using FP actuators.

 

18, or 25? I can go through this with you if you are interested, for whatever it's worth, because it sounds like an unusual scenario at first blush and it piqued my interest.

I personally have only used the 18# unit. I love it. The 25 pounder is used by a lot of the peeps running Blacks. I have said it before that I prefer running a heavily preloaded 18# actuator to running lightly preloaded 25# unit.

Did you mention what the peak boost levels was on the turbos? The funny thing is that I have never heard of the symptoms you are complaining of. Strange to have two turbos with the same unusual issue though.

 

If I recall, Aaron, at English Racing, described some quirky, idiosynratic, boost control behavior re the FP Blacks. I don't remember exactly. Maybe he will chime in though. I think that it had to do with boost creep at low preload levels...or something like that.

When you state above that, "....the wastegate was seriously preloaded...", that is not providing me with any useful, detailed info. That is no different from saying that he was, "...running a whole lot of boost..." We'll need to know to what exact PSI it was preloaded to. Exact numbers please(PSI, BAR), not qualitative statements.

 

Well unfortuantely at this point I won't be able to provide all the information you want, but I will try to get it. Here's what I know:

Car 1 - Evo3. Was running a factory 16g without any weird behaviour. The turbo was changed for a brand new FP "old school " red - It's not on their site anymore but it is basically a new DSM red without the HTA wheel. They had a special deal on them sometime ago. I believe it is an 18# actuator also but will have to confirm. When the turbo was installed my mechanic preloaded the wastegate signficantly - again I can't say by how much but he told me he put "maximum preload". The MBC was backed off fully and the boost went up to 28 psi, but the car didn't make full boost until about 6200 rpm.

I'm directly involved with car 1 as it is at my shop. In diagnosing the problem we found that the leakdown was high on this car and we pulled the head and pistons and found issues with both. The owner decided to go with a stroker setup and the engine has just gone back together. It hasn't been driven in anger as yet. So I do not know if the slow spool is resolved.

I would chalk up the problem to being the high leakdown but spool was normal with the 16g and we have another car with an FP Black with similar leakdown numbers and it spools up like normal.

Car 2 - Evo 9, FP Black. Belongs to a friend but is worked on at a different shop. His experience only happened over the last few days. Not sure if he has the 18# or 25 # actuator. He was running 28 psi but had a 3 psi taper up top that he wanted to get rid of. He got the wastegate preloaded - by how much I don't know. I assume he had to re-adjust his MBC to get 28psi. Boost taper dropped to 1 psi or less but max boost rpm increased from 5k up to 6k. He went back to his mech. and he reduced the preload and spool is back to 5k with a 2 psi taper.

I've never heard of tensioning the wastegate reducing spool (or experienced it personally before) so I was just curious if anyone else has seen this or if some other issues are at play.

 

Whenever one is troubleshooting one of these internal wastegate issues and the spring pressure or preload level (if you want to call it that) is called into question, it is extremely helpful to know exactly what PSI level, the wastegate spring pressure is actually at. One needs to establish a baseline pressure level and start from there. At the Doctor's office the nurse first takes your blood pressure to establish a baseline level. Otherwise we are shooting blind.

The first thing that I ALWAYS do with an unfamiliar turbocharged car is test and ascertain the gate's current and actual preload level. I realize that it is a pain and all, but I take nothing for granted. Always as a first step I disconnect any boost control device whatsoever and run a hose directly from the WGA nipple to the nipple on the. I proceed to then take the car for a WOT run in 4th and establish the car's actual wastegate spring pressure level.

With all due respect, I personally choose not to rely on whatever MHI, FP, Blouch, MAP, or etc., considers to be an optimal, or "proper"generic preload setting. I certainly don't rely on what the previous owner, the hotshot tuner, or whoever considers to be proper preload, "eyeballed" preload, or heavy preload, or lots of preload. They may get it "right", but I always at least double check their preload setting. Don't assume anything. Eliminate the Fudge Factor.

So, first, as a prerequisite, determine precisely the current level of preload before starting to make any actuator adjustments.. I furthermore, consider the common ballpark methods of setting preload: i.e. 1) the 3 additional turns beyond base spring pressure method, and, 2) the other method of half a hole on the turnbuckle to be as stated, merely ballpark estimates.

Sorry for the rant. But, the point is that to troubleshoot your issue it is best to establish a baseline reference: Always ascertain the current preload level first. Once you have that PSI level established, then adjust the spring pressure to the base spring pressure level. This gives us the proper baseline information. Don't forget to first disable the boost control device and run the actuator straight off the compressor outlet source.

 

I have never heard of this particular configuration. I mean a non-HTA, OS Red. Not saying that it has never existed.....it is just beyond my recollection (sure, that's not saying much) . Of course, I have no DSM background, unfortunately..and jjust because I can't remember it having existed, does not mean that it didn't. Sorry for my lack of knowledge.

Still, I am trying to visualze this turbo that you are describing. So, bear with me. It features standard, reverse rotation? What I am really curious about are the housings. Is it configured with a IX compressor housing, or an VIII housing? What of the turbine housing: are we talking a 10.5? Thanks.

 

I am curious as to what two housings this OS Red has. Is it fitted with an VIII, or a IX compressor housing. How about the turbine housing? Standard 10.5? Thanks. I am just trying to visualize the external configuration.

 

You guys might be able to help me.
I have a 2.3L Evo IX with a Fully Ported EF4.
I installed the turbo with the wga set so it could be installed easily on the turbo flapper. Boost was 23psi, with boost controller fully opened (no boost control). Once I fully closed (max boost) the boost controller I was only able to boost 25psi. I proceeded the next day to do about 3-4 full turns on the wga arm, and with the boost controller fully closed I was getting about 28psi.
I assume the EF4 turbo should be able to boost way higher, but the more I preload the harder it gets to install the damn WGA Arm to the Flapper. If I want higher boost, do I have to keep preloading until I get to the desired boost level? I still have a good 3-4 more turns I can do, thats with the nut still installed. If I preload more, and I am still not getting to the 32-35psi I want, I will have to remove the nut to allow more preload on the wga?

How do you guys install the WGA Arm onto the flapper once its preloaded? Strength? It gets very difficult to install the more preload you have.

Thanks alot
-selp