Hi guys, first time posting. Just bought my first evo. I need help with a quick question.

First the car,
2004 Evo RS
Exhaust and boost gauge are the only go fast mods

I did my first pull with the gauge installed and it was spiking at 12PSI and holding at 11PSI(basically it holds steady the entire way to redline). I am a DSM guy so this sounds great for a DSM but this is not a DSM. From reading evolutionm it should hit at least 16PSI right?

I am at 5200ft running 91 Octane. It's dry and 70 deg F. The vacume wiring is correct (matches the little picture under the hood). Boost source is between the FPR and the intake manifold.

Why is the car only running 12PSI? Actuator spring wearing out? Something to do with the ECU? Boost leak?

I have a boost controller in the mail and EVOscan cable on the way too. Just hoping I can figure this out before I turn up the boost manually.

Thanks for your Help
David

 

i would say the vacume lines from the wastegate is connected straight to a boost source like the blowoffvavle line! when you install the boost controller make sure the wastegate line is on one side and the boost source is on the other side and you should be fine. Right now the car is just running off of stock wastegate which is 12psi.

 

take a picture under your hood so we can see your lines. more than likely the previous owner may have had a mbc/ebc.

 

you evo had a manual boost controller on it or some ebc then was put back to stock. id bet my left nut on it.

i bet there is not restrictor pill anymore and therefore you are running wastegate pressure.

you need to either get an oem pill or get a boost controller

 

You guys must be right. I took off the waste gate actuator and made the rod shorter by 3 full turns. I can now get 13PSI out of it.

I didn't even think of the restrictor. The MBC will be here thursday and the evoscan cable will be here wednesday so I am set.

Right now it looks like the Waste gate actuator is hooked up to the BCS but is also tee'd to a nipple on the turbo outlet pipe. The other side of the BCS is hooked up to the intake....

For the MBC I plan to take the soruce from the BOV line and then run the other to the wastegate actuator.....

 

Whoa, I wouldn't have touched the WGA. That is a big change for what is a small problem. 3 turns is a LOT and will change the pre-load quite a bit. The reason you are seeing wastegate pressure is because you don't have the stock boost hoses. You can't just install plain vaccuum hoses in the stock configuration - it has to be the actual OEM boost hoses with the 2 restrictor pills in the right place.

With an MBC, this won't be a problem, but while using the BCS, you won't see good boost unless you get the OEM lines, which are $15. I personally use the compressor outlet pipe as my pressure source.

 

I am thinking the previous owner put the car back to "stock" before they sold it.

Any negatives for leaving the WGA three turns shorter? I will be installing the MBC and aiming for 19PSI for now....

 

That scenario has happened countless times on here, so it's very likely. The moment I see a post that says "OMG 12psi," I know exactly what it is most of the time. In fact, when I first read the preview of your post and saw the phrase "12psi," I didn't bother to answer since I've answered this same question a hundred times it seems, but then I saw you were in CO.

We don't typically mess with the stock WGA preload that much, since it's set very well from the factory, but if you did it 3 full rotations and are just seeing 13-14psi, then it means you won't have to turn the MBC as much to get to your desired boost levels. Be aware of spoolup, spike, and boost retention, since you could potentially have some side effects of the stronger preload.

Remember to use a different hose configuration with the MBC that doesn't have a tee down by the wga. Just do one clean hose from the WGA to the MBC and one clean hose from your pressure source to the MBC.

 

Turn the boost up with a MBC!