Hello All:

Can someone please help me out here? I have a 87 300TD with the Garett T3? turbo and wastgate set up. The rear of the wastegate has a threaded rod protruding from it attached to a longer rod which is connected to the valve assembly. The union of the longer rod to the wastegate has a locknut on it, and the other end is a coupling with a C-clip.

My assumption is that the boost is controlled by how much pressure this valve,/rod assembly applies on to the wastegate spring. This in turn is dialed in through the threaded rod, applying pressure on both the valve and wastegate. Therefore threading the rod assembly so that it applies more pressure outward will raise the boost pressure.

If I'm on the right track so far please let me know.

So the REAL question is how the heck do you get to the locknut on the rear of the wastegate? Is there some trick to adjusting this without taking off the EGR, egr union assembly, crossover pipe etc.???

I have tried to get at it with different angles of attack, tools etc, and when I started for the sledge, I thought, I'd ask

Current boost is 12-12.5psi max. My tech specs call for 13.7 and adjusted towards the high side. I would like to get it to 14psi max. IS this OK for these engines??

Thanks,
Bill

__________________
Stable Mates:
1987 300TD 310K mi (Hans)
2008 Jeep Grand Cherokee OM642 165k mi (Benzrokee)

The easiest way is to install a boost controller in the wastegate hose. They are fairly inexpensive and work well. Adjustments are then quick and easy. 14psi is just fine for the 603.

__________________
-disav

99 E300 TURBODIESEL Astral Silver 282K - AMG brakes, suspension, monoblocks, speedo & interior - Full Load Maxed on IP by custom Speed Tuning USA Chip - T3/T4 Garrett - EGR/MAF delete
98 E300 TURBODIESEL Alexandrite Green on black leather 289K
95 E300 DIESEL Green Queen 267K SOLD
84 300D 216k SOLD
87 300D 299K #22 head - intercooler - full load adj. - 8sec 0-60mph - SOLD
76 300D 214K SOLD

The easiest way is to install a boost controller in the wastegate hose. They are fairly inexpensive and work well. Adjustments are then quick and easy. 14psi is just fine for the 603.

Please forgive my ignorance, but how does a boost contoller work hooked-into the wastegate hose, how does this work or affect boost? Also what would you say is the upper, yet safe limit on boost for these engines, if 14psi is no problem how about 16psi?

I have a medium intercooler that I'm planning to add and use that to add more boost later.

Thanks,
Bill

__________________
Stable Mates:
1987 300TD 310K mi (Hans)
2008 Jeep Grand Cherokee OM642 165k mi (Benzrokee)

Firstly, if you add boost beyond the factory specs, you are not going to get any more performance out of the vehicle unless you add more fuel.

If you add more fuel without an intercooler, you risk melting a piston, depending on how long this additional power is present for. You might get away with 15 seconds however, 2 minutes would be a killer. Nobody knows and it depends on your specific engine.

So, anyone who is modifying these engines for more boost and fuel is well advised to add an accurate EGT gauge that you can monitor constantly from the driver's seat. Making adjustments without it is simply playing russian roulette with a very expensive engine.

Thanks for the reply Brian.

My objective currently is to get the car up to spec. I'm 2 psi shy of that goal right now and would like to remedy this situation first.

Future plans include addition of an intercooler, modified IP and EGT to monitor results. With respect to the EGT, I was contemplating on removing the EGR and blanking that off, as well as capping the exhaust connection, but then it dawned on me, this may be a great place to tap in the pyrometer.

Any thoughts on that or where would be the best place to tap in the pyrometer?

Thanks,

__________________
Stable Mates:
1987 300TD 310K mi (Hans)
2008 Jeep Grand Cherokee OM642 165k mi (Benzrokee)

The best place is to drill and tap a 1/8" NPT thread in the exhaust manifold, right at one of the exhaust ports. The only problem with this is that it's dangerous to do it on the vehicle because any chips fall into the manifold and head into the turbo.

I do believe that some members have tapped it in place, however, I'm not sure of exactly what procedure can safely be utilized.

Any other location, such as after the turbo, gives you meaningless data.

Before you go about adjusting your boost to spec, check your 0-60 times and make sure those are in spec. If they are, then adjusting the boost probably won't do much (if anything).

One advantage of a boost controller is not to raise max boost pressure but to change the boost profile from a ramp to an impulse. Typically the wastegate creeps open as pressure builds so you have a bit of a leak as you're accelerating. A boost controller such as the ones sold by www.dawesdevices.com/boost.html holds the boost signal to the wastegate until the setpoint. This should allow boost to build more quickly. Something in the design prevents boost spikes.

The general trick to tapping the exhaust manifold for an EGT sensor is to drill with the engine running. Exhaust pressure should blow the drilled material out rather than to the turbo. Also the turbo isn't spinning at idle so the material will go right through. I've seen it done successfully on a few turbo cars.

Since this is a 603, remove the turbo feed pipe and start the engine you're done!

Sixto
95 S420
87 300SDL

There is very little exhaust pressure at idle. I'd be surprised if chips that fall off the end of the bit would blow back up through a 3/8" (approx.) hole.

AFAIK the turbo is spinning at idle. The exhaust has to go somewhere and it must pass the turbine wheel so the turbo will spin slowly. The chips may very well pass through the turbine wheel, however, if one of them gets caught between the turbine wheel and the housing..............

If it was done successfully, I would say that there is a bit of luck involved with the presence of small chips that pass the turbine without problems.

There is a pretapped hole in exhaust manifold. It is on the one closest to the front of the motor. Unscrew the bolt and an autometer probe screws right in. I am running 16psi right now. But I have turned up my pump and added an intercooler. I suggest adding egt gauge, then intercooler, then pump adjustment, then boost adjustment. That way you are always seeing what your adjustments are doing to the egts. Monitor smoke off idle and full throttle and adjust according and next thing you know you will have an 8sec 0-60 car.
If you just want to get it to stock, set your boost at 14psi with a boost controller. No need to go anymore unless you have done the above modifications.

__________________
-disav

99 E300 TURBODIESEL Astral Silver 282K - AMG brakes, suspension, monoblocks, speedo & interior - Full Load Maxed on IP by custom Speed Tuning USA Chip - T3/T4 Garrett - EGR/MAF delete
98 E300 TURBODIESEL Alexandrite Green on black leather 289K
95 E300 DIESEL Green Queen 267K SOLD
84 300D 216k SOLD
87 300D 299K #22 head - intercooler - full load adj. - 8sec 0-60mph - SOLD
76 300D 214K SOLD

Have you posted any pictures of this set up, mdisav? I for one would be interested in seeing how you connected pipes in place of the crossover.

__________________
'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

Thanks eveyone for your great suggestions, I'll look into a few things first.

What's funny is that both the shop manual as well as the owners bible both state to check and "adjust" the turbo boost pressure frequently. Then they go on to describe every other turbo and engine combo around and provide on skimpy drawing of a like rod assembly for a garret and no info on how to adjust.

I'm looking into EGT set-up, have order a Hallman boost controller and dry fitted my intercooler today, no plumbing, just a dry fit for size and pipe locations. I will check to make sure my car has the service port on the exhaust manifold and use that for the EGT probe.

So far the biggest issue I can see if the IP. From what I have researched this unit on the 603 has no easily adjust ALDA screw, and would require shimming and bench set-up, which is beyond my capability so would likely be farmed out. If this is easier than I assume, please let me know how.

Thanks,
Bill

__________________
Stable Mates:
1987 300TD 310K mi (Hans)
2008 Jeep Grand Cherokee OM642 165k mi (Benzrokee)

While the ALDA adjustment screw is not accessible on the 603, with a little patience, you can remove the entire ALDA, make the adjustment, and reinstall the ALDA. A bench setup won't get you much. You need to make an adjustment, drive the vehicle after seeing what it does, and adjust again.

Dave (gsxr) has it down under 3 minutes to remove the ALDA, so, it's certainly possible with some practice.

Here are some pics of my modifications. Mauri H. and Casey have added larger intercoolers than me and have the plumbing going directly into the other side of the intake eliminating the crossover. I wanted to do a low budget one. I used an audi TT intercooler and stuffed it under the passenger headlight. Egts generally stay below 1200F. If I am into the pedal up to 100mph then I start to go to 1250F and slightly higher approaching danger zone. Mauri and Casey have lower egts but more extensive modifications.

Also in order to keep the o-ring tube out of the turbo secure, (it use to be held snug by the egr part of the intake and the crossover) I hose clamped a rubber piece of plumbing to it then tack welded that to the edge of my exhaust manifold. It is not recommended because it has been said that it can possibly lead to cracking down the line. I just went for it. I also cut off the part of the exhaust log that lead to the egr and welded a plate to it. That is what is wrapped in exhaust wrap.

I also removed the mass air flow sensor since the consensus is that it is for managing the egr. I just placed a 3 stage itg foam cone filter in its place.

Attached Thumbnails

       

__________________
-disav

99 E300 TURBODIESEL Astral Silver 282K - AMG brakes, suspension, monoblocks, speedo & interior - Full Load Maxed on IP by custom Speed Tuning USA Chip - T3/T4 Garrett - EGR/MAF delete
98 E300 TURBODIESEL Alexandrite Green on black leather 289K
95 E300 DIESEL Green Queen 267K SOLD
84 300D 216k SOLD
87 300D 299K #22 head - intercooler - full load adj. - 8sec 0-60mph - SOLD
76 300D 214K SOLD

That looks good! How much of a performance increase did you note due to the IC. Could you turn up the fuel a bit at the alda? Did you notice a drop in EGT's?

I've got the parts for my install and gonna hit it soon. So far my EGT's with no alda adjustment run up to and beyond 1250 deg when I lay into it for and extended period of time. I also have a small IC and locating it in the same place as you did and I'm hoping for a 200 deg drop in temps. We'll see. If you have any info, please share.

__________________
Stable Mates:
1987 300TD 310K mi (Hans)
2008 Jeep Grand Cherokee OM642 165k mi (Benzrokee)