I got the 350SDL turbocharger, and you were correct - it's a pressure wastegate, not vacuum. Cool! Looks like the FSM was wrong on that one. The shaft has more play than I like but the hot side doesn't look wet with oil, so I'm hoping it will be OK. If the test is a success, I can always rebuild it or replace with a different turbo as required. I started taking apart the engine to swap turbos, might have time to work on it more this weekend.



I experimented with that and found that when setting the boost at 20psi, the wastegate shaft seems to be almost fully extended in the "closed" position. I'm concerned there may not be enough travel to allow it to fully open. I was going to set mine at 16-18psi and use an external boost controller instead.

If you guys need a spare pressure actuator from a 350's turbo let me know, I have one.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Thanks J.

Mine has some travel left at 18.5psi, so I think I'll be fine. The proof is in running it, see if the wastegate limits boost properly or if it creeps higher. As the turbo was designed to run 135,000rpm at stock boost, I'm really afraid to push it much higher without knowing the maximum operating parameters, ... might already be beyond at 18.5!

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Gone to the dark side

- Jeff

I have noticed that the Cruise Control limits full-travel of the IP rack/arm, is this normal? There is no way to avoid it other than relocating the ball lower on the arm to provide less cruise-actuator travel.

__________________

Gone to the dark side

- Jeff

When you tweak the full load on a stock pump, which moves the external throttle lever, you must re-adjust all three external linkage rods, and move the ball on the arm as needed. It's a lot of trial and error but you should be able to set it up such that the throttle lever will move from idle to WOT with no restrictions, and without the cruise actuator causing problems either. It is VERY tedious. One thing I liked about the 6mm hybrid is that the throttle lever is in the same position as stock, so there were zero issues with the linkage... I removed the stock/rebuilt pump and bolted in the hybrid, and didn't have to touch the linkage adjustment. It was perfect out of the box.

The linkage is adjusted so that at idle, the CC linkage is just free. It doesn't have as much travel as the IP. I guess I'll drill and mount a hole down further on the IP arm so that the CC doesn't need to travel as far, the only solution I can see.

__________________

Gone to the dark side

- Jeff

Somethin' doesn't sound right there, Jeff. I didn't have to drill anything on mine even with the lever moved about as far as possible (almost touches the pump body). It took a LOT of experimenting with the rod lengths though.

Just the one rod, from the IP to CC. Just doesn't have the throw on the CC. It is a 3.5L pump, I should look to see if the CC on the 3.5 is the same part.

__________________

Gone to the dark side

- Jeff

UPDATE:

Original 3.0L KKK turbo is off the car and on the workbench next to the 3.5L Garrett. I need to swap a couple of things around and then bolt up the bigger turbo. I set the Garrett wastegate to approx 4psi higher than stock setting, should be interesting to see the actual pressure on the boost gauge.

Note that the .97x engines were set at .85bar where your 3.0L was originally set at .95bar nominal.

Are you still running stock exhaust with the cat?

__________________

Gone to the dark side

- Jeff

Ooops, shoulda clarified. The 3.5 Garrett wastegate started to move at 14psi on the gauge. I upped it to approx 18 psi. However this may not be the actual measurement on the dash boost gauge. I can't test the KKK (which I had adjusted from stock anyway) as the KKK is a weird "controlled bleed" design which you cannot test on the workbench.

Cat fell off the car a while ago, zero power increase, but EGT's dropped marginally (maybe). Didn't get time to work on the car today, hoping for sometime this week. Darn day job keeps getting in the way, lol...

Well the W126 350 never had a cat anyway, so if you have the updated angled injection head you'd almost be emissions compliant

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Brief update:

Got the 3.5L turbo installed and running. Boost gauge shows 15psi (1psi less than on the workbench). Good news is, the boost doesn't vary even a little at high RPM, it stays pegged at 15 (the KKK would always drift down as RPM's increased). Bad news is, I need more boost. I don't think there's enough adjustment range for the stock wastegate so I may leave it as-is at 15psi and try an external boost controller. I'm looking for 20-22psi. Adjusting the rod with the turbo installed looks like a RPITA.

For grins, I clamped off the wastegate hose and went for a drive. Boost went over 25psi under heavy throttle, although I didn't give it full throttle or high RPM's - didn't want to risk damaging anything with the wastegate sealed shut. But at least there appears to be decent capacity. IAT's climbed rapidly to 200-250F under these conditions. The bigger turbo doesn't spool as quick as the little KKK but I kind of expected that.

I think this setup will allow steady peak boost at 20-22psi, which is great. But until I get it dialed in, the question remains if the additional airflow will solve my low power problem at high RPM's.


UPDATE: I just urdered a Hallman ES boost controller, hope to have that installed within a week.

I am very late coming into this thread and it looks like too late to help GSXR with the KKK. My suggestion was going to be to use a manual or electronic boost controller. The adjusting of the waste gate rod to control boost is not reliable at high boost levels and drilling out the bleeding orifice can't be undone if you want to go lower or return to stock. Boost controllers simply add another hole to bleed out of so the actuator moves later in the boost curve.

I was also going to ask if you tried to run without the air filter to see if that was restricting the air flow at high RPM but your Garrett already answered that question.

Most of my turbo modification experience comes from the gasser side of things and high EGT's mean a lean condition and more fuel lowers EGT's. Is this not true with diesel? You mentioned you wanted more boost to lower your EGT which I thought was odd.

I was looking at all of your intercooler pictures in your personal web collection and, in my opinion, the easiest way to hook one up with the least amount of modifications is to clock the turbo so it is pointing down, use the Saab IC that has the inlet and outlet on the same side, and hook the outlet to the cross-over pipe. Having the turbo outlet pointing down gives the extra clearance needed to put in a 90* elbow on the crossover pipe. Having the IC inlet and outlet on the same side nullifies the need to run pipe from one side of the engine to the other. I just don't like IC's with plastic endcaps - they can blow off at 20 psi - but they can be held together with metal straps too. If you can't find a place to fit the IC directly in the airflow without changing or cutting your bumper you can put it somewhere else and use an electric radiator fan on it - maybe flat above the turbo like a Subaru.

For the oil cooler line (or is it water?) I think you can cut off the metal pipe and tap the remaining flange for a braided stainless steel line. I am just thinking out loud on this one.

I currently live in Marin and used to read your posts many years ago. Weren't you importing manual 5 speed transmissions for w123 conversions?

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-ggg

Clocking the turbo is possible, but having the wastegate mounted to the inlet side makes it complicated.

As far as more fuel cooling the cylinders, that is true with a direct-injection engine and one reason why you see tractor-pull etc. engines belching smoke. With the IDI engine however, overfueling the little pre-chamber has some nasty results, more air and an aftercooler are the best solutions.

As far as the Saab intercooler, I've been told that there's a pretty high pressure drop across it. This is a problem as the stock turbo and elements don't really push enough fuel to need an aftercooler, unless you go to a larger turbo and larger elements, in which case you'll probably need an aftercooler that flows more air (less pressure drop) than the Slaab unit.

Really for street use, seems that an air/water unit is best just for packaging reasons, the 124 just doesn't have much space for a big cooler in a stock bumper and the short bursts of heat wouldn't really heat-soak the coolant in it before having a chance to catch up. Otherwise, running the turbo output down, crossing the front of the car with a nice aftercooler, and feeding the intake (which is on the other side on the OM60x) is a better option than crossing the head the way the current airflow does, ... IMO.

__________________

Gone to the dark side

- Jeff