Tim’s Garage Episode 17: Saturn Sky Redline Turbo Wastegate Actuator Adjustment / Solstice GXP

In this episode, I outline how I resolved a low-building and less-than-thrilling boost pattern. After many rounds of tuning and some less than uplifting boost numbers, I could not help but think there was more power to be found. The observed condition was slow but linear, climbing boost to 6000 RPM where it would peak around 5500 RPM. Another observation was that at high RPM when you decreased throttle position, boost would increase slightly. It “seemed like” the wastegate might be leaking or not working correctly and I decided to check the mechanical settings and found an incredibly EASY FIX. Follow along and observe how easy the correction was.
A fellow Sky lister named Andreas provided this more detailed information:
In the official turbocharger wastegate actuator adjustment technical service bulletin they say 3 turns tighten from (same as Tuner Westers Garage recommends)
1) Remove the turbocharger heat shield.
2) Loosen the lock nut (2).
3) Hand tighten the lock nut (1) until it is seated on the wastegate arm and slight spring tension is observed.
Note: Ensure the wastegate actuator rod does not rotate during the tightening procedure. If the rod does rotate, it will be necessary to start the procedure again.
4) Mark the lock nut (1) with a paint pen to mark a starting position and tighten three complete turns.
Note: After the lock nut (1) has been tightened three complete turns, it should not move for the remainder of the procedure.
5) While holding the wastegate rod tighten the nut (2) hand tight.
6) Tighten the nut (2) while holding nut (1) in place to 10 N·m(89 lb in). Apply threadlock (P/N 12345493) to the wastegate actuator rod threads on both sides .
Note: The wastegate adjustment is sometimes a very fine process. When adjusting the wastegate, only small adjustments should be made. Loosen one nut at a time and only adjust the nut one turn at a time; then tighten the other nut against the shaft and test drive to verify. This may have to be performed several times to achieve the desired boost level. To ensure proper adjustment, the vehicle should be at full operating temperature when testing. The vehicle will be very hot and may need to cool between adjustments. Too large of an adjustment can cause repeat DTCs.
Turbocharger Engine Underboost
To increase boost, adjust the nuts (in) towards the actuator; in essence making the shaft shorter.
Turbocharger Engine Overboost
To reduce boost, adjust the nuts (out) towards the end of the shaft; in essence making the shaft longer.
#saturnsky #turbomods #diy #lnf #myskyisfasterthanyours #gmperformance #solsticegxp #gxp #garageprojects #bigwheelturbo #opelgt #bigwheelturboinstall

[@vojislavspasic8619]

I just bought a 2008 SKY red line, and I am absorbing all your videos. Can't say thank you enough... YOU are amazing.

[@350tiger]

I appreciate that

[@BrianRoediger]

Again, you are the ONLY person who posting any really useful information about these Kappa cars. This is absolutely invaluable! Thank you so much!

[@350tiger]

I appreciate that Brian ! Thank you ... next I think will be how to understand HP Tuners ... Kappa Edition ... once I figure it out enough to explain it 🤦🏻‍♂️

[@herbh9348]

Tim is the man...car genius!!

[@350tiger]

Ha … Thanks Herb!

[@emersonsullivan9768]

Thanks for the video, extremely helpful

[@350tiger]

Glad it was helpful

[@mjones53]

great video(s) thank you for making them.

[@yadircastillo7640]

Gracias excelente video

[@Salvadorz24]

The stock wastegate canister is rated at 4 psi

[@350tiger]

Salvadorz24 I tested last night and the Stock actuator set as it was removed from the car starts to open at 6psi and is fully open at 12 psi . The new replacement Big wheel adjusted to the 3 turns of preload starts to open at 7 psi and is fully open by 14 psi. I did notice a slight spring or clicking noise as the actuator was releasing at 50% of travel in return. No noise as it opened but as I repeatedly cycled it with my pressure tester it made the same clicking noise like a spring releasing tension inside the wastegate housing. I moved smoothly and actuated un is full range just had the clicking noise ... the original turbo wastegate is perfectly silent as I actuate it ... I would love input if you have any.

[@SuperMacGuy]

Tim, good tips there. I'm wondering if you can reply or do a new video if you had the car on a dyno. I'm confused as to A: Benefit of the BW turbo because B: the learn down on the ECU. Can the learn down be really, fully, defeated by a tuner with the right software? It would make no sense to upgrade anything if the GMPP sensors and tune got you 290hp/340tq and then the ECU pulled any hardware mods back down to that. I'd love to have the LNF with the same RPM upgrades plus BW turbo pushing 350hp/400tq (if it'll not blow up). Additionally, do you think you need a new fuel pump?

[@350tiger]

I have not had it in a dyno yet as I worked through some tuning issues ... through HP Tuners you can ‘disable’ the learn down by setting some of the torque factors to 100% at each of the values. To explain this you need HP Tuners in front of you and look through the actual tune. My next video I will attempt to describe that.

[@350tiger]

I missed the rest of your question Chris ... other than the big wheel and the other Bolton’s in my videos I have not touched fuel delivery or injectors ... the stock system seems to fuel the big wheel well enough to provide continuous airflow through 6300 RPM ... the data logs show 35 lbs per minute of airflow with no higher RPM over 5000 drop off like the stock turbo.

[@mendhamgolf]

Tim, another great video!! So if I'm understanding you correctly when speaking about the pre-load, do you mean you want the wastegate valve to stay closed a little longer, or harder to open, or do you want to adjust so there isn't that much tension and the wastegate valve opens much easier? Thanks buddy!

[@350tiger]

You want to ensure that you have some positive pressure holding the wastegate closed. Tightening the lower nut pulls the actuator rod and acts to slightly compress the spring inside the actuator housing. My factory unit had only an additional 1.5 turns (0.051”) (or 1.25 mm) after it was finger tight against the wastegate bellcrank. I have been told that 3 times or 3mm of preload is what is recommended by many forum tuners and turbo rebuilders. I will likely add another turn of the lower nut to have 2.5-3.0 tunes of preload. Read the notes under the video I added a great clarification on this. Thanks for watching Edward!

[@mendhamgolf]

@@350tiger Thanks as always Tim. I understand now. I also have a newly installed big wheel turbo from Martin Scott and I'm going to check if mine is adjusted correctly.

[@350tiger]

Edward Russo I also did a test and found that once it is seated and adjusted correctly the actuator started to move at 7psi of pressure and was fully open at 13-14psi. The stick until with 0.51” of preload started to open at 6psi and was fully open by 12 psi.

[@mendhamgolf]

Tim Ronak okay thanks Tim! You're the best!

[@350tiger]

Edward Russo if you are building boost right off idle and have +20 psi at 3000 and up my guess is you are fine!

[@clintonmichaels9259]

I was looking at the turbo bay big wheel. Is it worth the money. Can you feel the difference. How much up you gained. Last question who did the tuning. Thanks. PS I turn is a half turn. So to adjust is 6 turns you need 12 turns.the end of the wastegate thread should be in the middle. On the showing threads on the wastegate.

[@350tiger]

Clinton yes in my opinion it was worth the upgrade. I still have more tuning to go as I just discovered the incorrect setting. I have used Martin Scott at RPM to teach me and act as my tuning consultant 😀 Clinton I am not sure what you meant in the last 2 sentences ... the preload only occurs one way and because I did not want to disturb the upper paint mark on my factory turbo I did not show that clearly ... what I would do is 1 adjust both nuts to allow the wastegate bellcrank to freely move up and down the wastegate actuator. 2 push the wastegate closed and snug the lower nut up to the bell tank lightly finger tight. 3 spin the upper nut down back to the bellcrank and leave 1.5 - 3.0 mm of gap between the nut and the bellcrank for preload. My GM turbo had 0.051 of an inch gap which is about 1.3 mm. 4 hold the upper nut with a wrench to prevent movement and tighten the lower nut up against the bellcrank and tighten securely. 12 turns would be way excessive and the unusual location of the arm versus the wastegate bellcrank for my unit is likely because the wastegate actuator is an aftermarket replacement and not a GM OE version. If I have any more difficulties I will be putting the GM one on. Thanks for watch 👍🏻

[@350tiger]

Clinton ... another listed name Andreas provided this information: In the official turbocharger wastegate actuator adjustment technical service bulletin they say 3 turns tighten from (same as Tuner Westers Garage recommends) 1) Remove the turbocharger heat shield. 2) Loosen the lock nut (2). 3) Hand tighten the lock nut (1) until it is seated on the wastegate arm and slight spring tension is observed. Note: Ensure the wastegate actuator rod does not rotate during the tightening procedure. If the rod does rotate, it will be necessary to start the procedure again. 4) Mark the lock nut (1) with a paint pen to mark a starting position and tighten three complete turns. Note: After the lock nut (1) has been tightened three complete turns, it should not move for the remainder of the procedure. 5) While holding the wastegate rod tighten the nut (2) hand tight. 6) Tighten the nut (2) while holding nut (1) in place to 10 N·m(89 lb in). Apply threadlock (P/N 12345493) to the wastegate actuator rod threads on both sides . Note: The wastegate adjustment is sometimes a very fine process. When adjusting the wastegate, only small adjustments should be made. Loosen one nut at a time and only adjust the nut one turn at a time; then tighten the other nut against the shaft and test drive to verify. This may have to be performed several times to achieve the desired boost level. To ensure proper adjustment, the vehicle should be at full operating temperature when testing. The vehicle will be very hot and may need to cool between adjustments. Too large of an adjustment can cause repeat DTCs. Turbocharger Engine Underboost To increase boost, adjust the nuts (in) towards the actuator; in essence making the shaft shorter. Turbocharger Engine Overboost To reduce boost, adjust the nuts (out) towards the end of the shaft; in essence making the shaft longer.

[@44WillysMB]

Were you getting a P0299 DTC ?

[@350tiger]

I was not getting any code as it was a mechanical actuation issue and the computer did not pick it up

[@44WillysMB]

@@350tiger That is odd, as mine is doing what you describe ,though it does trigger the P0299, and sometimes goes into "limp mode".

[@350tiger]

@@44WillysMB it may be that your situation is that the bypass ‘door’ has fallen off of the arm or has become stuck open. That is hard to diagnose by text but I would test the actuator with a vacuum pump.

[@clintonmichaels9259]

What you thinking the extra hp. With the big wheel. 40 to 60. All the forum s I been to say around 10hp. That's hard for me to believe. I think I will order the Hp tuner file from zzp.

[@350tiger]

Well I went from stock straight to stage 3 with Intercooler, charge pipes, 3 bar map sensors and open cat ... my butt dyno says likely 100+ over the stock 260 HP ... so around 350-370 now and will use dyno time to get the last bit out of it.

[@clintonmichaels9259]

That's what I am looking for around 60 to 100 up .right now I just have the trifecta tune. Works ok there is no top end power after 90 mph.

[@350tiger]

clinton michaels the Trifecta tune as I understand locks out your Em and you will need to have that removed to secure any other tunes ... including retuning for a Big Wheel

[@clintonmichaels9259]

@@350tiger I got a extra ECU off eBay. I had the Chevy dealer code my Vin to it.