The wait is over.Forge K04 actuator testing.

Well for those of you that have been waiting for this, it's
finally here.I have no knowledge of the actual release date, but for the past month i have installed and tested one of the few existing Forge K04 actuators out there, and this thread will contain my thoughts and findings, along with (of course) graphs and numbers.I will be updating this slowly with more data and pics.

For starters, the actuator itself.It has similar appearance to the K03 actuator, but the bracket is somewhat (a lot ?) different.The mounting holes on the bracket don't line up like in the K03 version, so you definitely need this if you have a K04.







Compared to the OEM actuator, the actual threaded part of the actuator is shorter.Having played with the nuts (the actuator's of course) the OEM actuator is pretty uselessly long, since Forge's length pretty much matches the opening range of the wastegate itself.

Installation was indeed a b*atch, as mentioned with the K03, but maybe even more so cause of the slightly different holes.I'm pretty handy with the wrench, but still i don't regret going to a shop for it (read further down to see why..).

After talking to Forge, i was instructed to try the Blue spring first, which AFAIK is the second hardest after the Red, and one hardest than the Yellow (the spring Forge uses for the K03 version also).I had been experiencing high N75 values at redline, and my reasoning was the excessive exhaust gas volume was pushing the wastegate open.When the install was over, i set the nut at almost OEM position and went for a run, but it so proved the Blue spring is TOO HARD for this turbo, and i wasn't ever able to control boost in an orderly fashion...

That meant the next possible spring was in order, which was the Yellow one.This however posed a HUGE problem, cause i seriously didn't want to redo the whole process, so i decided to remove the spring ANOTHER WAY...Don't ask me how, but i finally did it, and i don't wish it on anyone.So if Forge sends it with the Yellow spring....you leave it at that....

Going on, the whole setup needed some adjustment for it to work as it should, and having
Revo software and an SPS Plus made it a whole lot easier.
Boost needed to be adjusted to return to the OEM levels (remember we don't want to
use the actuator as a simple "wastegate tweak", its the spring that must do most of the change in how the car reacts), and i finally managed to narrow it down to a few settings
variations that do the trick.

As for the noticeable results ?Well all i can say is that its the hardest i've felt the car pull so far since i've began modding it.I can't really compare my results to the K03 ones (my car is a K04 car but it also has TONS of other mods, including cams etc), but what i mostly felt, could be felt in the low to mid revs, and not that much at the redline.

The car just pulled SO MUCH HARDER from 2000 rpm, and logs showed a +30g/s difference in the low to mid range.Now some might say that is actually the nut adjustment, and not the spring itself, but i don't think so.I had audible boost/wastegate flutter when i was hitting peak boost, and all of that is now gone.I am not hitting much higher peak boost (i actually set it up that way) but pressure now drops progressively, and not playing up and down...

Over all, i have to say this is HIGHLY recommended, but for me it is NECESSARY to be installed and fine tuned by a professional, or at least someone with a fair knowledge of how the wastegate/software works to maintain boost and have the car run at its best.

Graphs

OEM actuator



Forge actuator (yellow spring)



Graphs were made with different SPS settings to adjust for the increased boost in the low to mid range.There was not much difference in boost pressure at redline, but there was a HUGE gain in low to mid revs, WITHOUT a need to drop timing settings.You can see a difference of ~30g/s at 4000 rpm.

Somehow the OEM graph came out very "rough".Don't really know why that happened.
Both graphs are without any kind of smoothing.

i wanna see some numbers and logs for sure! keep us updated

alva8193 said:

i wanna see some numbers and logs for sure! keep us updated

Click to expand...

:thumbsup:

sounds great! i might have to get one of these when i get my k04, install it all at once

Interesting.

Looks like i'll be looking into one of these when i get home and get my K04 installed.

hey! what's up dimitrios

can't wait to see the numbers/logs, this may be my next mod

by the way, do you have k04 logs before the actuator? i want to compare them with mine.

molo said:

hey! what's up dimitrios

can't wait to see the numbers/logs, this may be my next mod

by the way, do you have k04 logs before the actuator? i want to compare them with mine.

Click to expand...

Yes i have logs, but i don't really think our numbers will match, firstly because i am running a European version of the software, and secondly because i have a different setup, different compression, cams etc.

But i will be posting graphs soon, so stay tuned.

As for the actuator, its a definite must is you are heavily tuned and know how to dial it in. :thumbsup:

I don't really understand what this does. This seems like one of those magical turbo upgrades which exceeds all understanding unless you speak klingon. All I hear was "IT PULLS SO MUCH HARDER!"

subscribed, I'm always looking for more K04 power:burnrubber:

GodSquadMandrake said:

I don't really understand what this does. This seems like one of those magical turbo upgrades which exceeds all understanding unless you speak klingon. All I hear was "IT PULLS SO MUCH HARDER!"

Click to expand...

what? you don't think the turbonator works?

Genome said:

what? you don't think the turbonator works?

Click to expand...

Oh yeah the turbonator works. I gained 3-4 inches in 3-4 weeks guaranteed and saved $300 on my car insurance at the same time.

GodSquadMandrake said:

Oh yeah the turbonator works. I gained 3-4 inches in 3-4 weeks guaranteed and saved $300 on my car insurance at the same time.

Click to expand...

I had to stop after 9-10 inches, as any more would provide discomfort for my partner.

GodSquadMandrake said:

I don't really understand what this does. This seems like one of those magical turbo upgrades which exceeds all understanding unless you speak klingon. All I hear was "IT PULLS SO MUCH HARDER!"

Click to expand...

Due to the greater amount of exhaust gases that flow from cylinders into exhaust manifold the stock spring of the actuator is too weak to hold the raise in pressure through the exhaust manifold. The wastegate prematurely cracks open and lets gases bypass the turbine, net result is a little lag and power loss. With the actuator from Forge, the proper spring (which firmer than stock) allows the wastegate to hold higher pressure in the manifold, but at the same let the ECU and N75 value control the boost level for any given engine load and throttle position.