I think I may be suffering boost creep with my WR turbo and FP high pressure actuator. No matter how low I set the boost controller, after the initial spike the boost creeps toward, and sometimes beyond, 22 psi once I get into the mid-RPM and higher range. I can see the boost needle rising as the RPMs come up. Occasionally it even gets into the mid-22 range (though I usually lift when the car feels a little "too strong") in the very upper RPMs. I have about a 1/3 hole preload on the stiff spring actuator and I think that also could be the problem.

This issue has been exacerbated significantly since I added my Helix O2 housing (had to reduce duty cycle on the EBC by 8-10% just for that) and the cooler winter temps.

In order to reduce the preload, I'll need to get an extender piece from FP since I have one of the shorter arm prototypes.

Anyone else see anything like this before with a high pressure actuator? Does this sound like something that I could fix by reducing the preload on the actuator. (What a pain that is to adjust since you need to pull the radiator to get the lower heat shield off to access the acuator.)

Thanks for any comments/thoughts.

p.s. These cool temps are crazy for power. Between the Helix O2 and the "winter weather mod," I've gain 30+ whp according to my Blitz Powermeter. I think I'm just going to hold off on using the alky until the Spring. Plenty of power with plain old 93 now

 

It definitely has something to do with the colder temps. Do you have anything to monitor your A/F?

 

Yes, a wideband gauge right on the windshield. I did just add a bunch of fuel to my tune for the denser air because I was getting into the 12s with the cooler temps, or it could have been the Helix O2. I don't know. The weather got cold after I installed it but before I retuned.

 

Well it sure sounds like boost creep but that is extremely hard to believe. The wastegate design on the EVO's is so good I have a hard time believing the car could boost creep.

David Buschur
www.buschurracing.com

 

Thought I'd bring this thread back from the dead as it appears that I've licked the problem.

When I first put in my WR turbo with an OEM actuator, boost was perfect. It went right to the set point and fell maybe 1-1.5 psi to redline.

Later, I installed a Helix O2 housing and a Forced Performance high pressure actuator, which they actually sent me for free since I had purchased a WR turbo before.

After installing those two parts, I had to turn my EBC way down to keep the same boost and the boost tended to rise in the mid range 1-2 psi and then hold about even to redline. That was last fall/winter when I did the original post above.

I chalked up the issue to maybe the actuator or maybe just the fact that it was 40 degrees out and boost was acting differently.

Well, my car was parked most of the winter, but this spring before really driving it much I pulled it apart and installed a Buschur-ported exhaust manifold and turbine housing. I also had all of the parts (including the O2 housing) coated.

With temps back in the 60-70s, I thought my boost problems would be over, but they actually got much worse. I had to turn my boost controller down even more and then no matter what I set the EBC to, the boost would creep about 3-4 psi by redline. So, in order to keep the boost reasonable I was basically running a spike to 17 psi with it creeping to 21 at redline. Car felt terrible.

So, I started troubleshooting. First, I checked the preload on the actuator. I had previously set the tension on the actuator rod according to the video on FP's website, which is very specific, so I doubted that was the problem, but my symptoms did seem consistent with too much preload and an actuator not opening all the way. So I took away ALL of the preload on the actuator arm. No change. The car came up on boost a little more sluggishly, but it still crept just as badly.

Then I connected the actuator directly to the turbo outlet with a short vacuum line to determine if either the boost controller or the lines to the boost controller were at fault. Still no change.

Finally, this morning before I work I swapped out the FP actuator for the OEM actuator. Problem solved. I did notice that my wastegate boost pressure is about 1 psi higher than it was before the ported exhaust parts (~12 psi).

It seems that the FP actuator doesn't like to run lower boost. My best guess is that it doesn't open the wastegate as wide as an OEM actuator. Does that sound like a reasonable guess?

Is anyone else on here running an FP high pressure actuator on pump gas?

Has anything like this ever come up with the Forge actuator?

My set-up is basically Buschur Stage 4 (264/272), WR turbo, ported manifold and turbine housing, Helix O2 and 3" TBE.

It's good to have this problem solved. Maybe now I can actually tune the car for the new mods.

If anyone has any thoughts or similar experiences, please post them up.

Thanks.

 

i have a 20g-9-5 with the high boost actuator, i was having the same issue. it would hit 1.5 and slowly climb. i was thinking, wow thats not right. so i turned my bc down, and down, and down some more,and it went away. also i want to say this was in the month of feb when this was happening. since then hasnt happened. the only thing that happens now is wheel spin when shifting to 2nd, if u can believe that. haha and i havent installed cams yet either, im assuming some tq will be lost when i put my hks 272's in.