603 ALDA tweak, CCW or CW?

[Hit Man X]

On the 617 the ALDA tweak is CCW but I wanted to make sure it's the same direction on the 603 as the manifold is off and going to the machine shop this week (sooooooooooooooo much crap in it from the EGR!).

Thanks!

[Ara T.]

Let us know how the car performs after the adjustment, our SDL is a slug off the line. How hard does that manifold come off?

[compress ignite]

Ccw

[Hit Man X]

Not too bad, I yanked it as it's SOOOOOOOO gross in there... I'm going to make a thread about it. EGR is evil. Apparently you can remove the ALDA with the intake in place but my hands are pretty large to get into that area and I needed to clean it anyway.

There's 12 bolts on the top (6mm allen?), two that hold the throttle linkage to the manifold, and two for that crossover on the top. Then the few harnesses. And a few for the IP lines.

Took me a while as the PO used three wrong bolts to hold it down. One 13mm and two 10mm.

Also I plan to check the glow plugs and ream out the chambers.

The SD has the ALDA maxed and it's a HUGE difference off the light. I cranked it all the way CCW on the 603 (hope it's the correct way) and it turned more times than the SD did... so I forsee the SDL really scooting off a stoplight after this. So they are pretty lean off a light, next will be to see what my PSI levels are on both cars.

[Ara T.]

Yeah, the 603 puts out what, 210+ ft-lbs torque?? Pretty good, but I can't tell with the way ours runs. I mean once the turbocharger spools up your head is in the back of the seat but you have to put the go pedal down too much to get it to move.

[Hit Man X]

Mine isn't that bad, it moves okay from a light off a dead stop. I adjusted my throttle linkage at the firewall, gutted the cat, removed the Air Flow Meter, and am trying a hacked air intake box. Ran to 117mph here last week even! If it matters, mine has the KKK turbocharger versus the Garrett found on most.

But the adjusted ALDA should be pretty slick if it made that big of a difference on my SD. I've heard most of the more emission'd turbo diesels run "lean" or with less fuel and boost than spec'd from the factory.

[pawoSD]

I heard/read somewhere on these forums that the SD's/D's (617) have better take-off torque/quickness than the SDL's do, just by nature. (more low end torque perhaps? The 603 is pretty "revvy") I have ridden in an SDL before where the pedal was mashed on takeoff....and mine is quite a bit quicker in that "initial lunge" but its after that point where the SDL really takes off.....but hey its more powerful, thats cheating.

[Hit Man X]

I think I'm going to road test it tonight, I'm very curious about the difference it will make. I have an extra 603 intake manifold I will just take to a machine shop to clean.

[Hatterasguy]

I have yet to drive a 603 that wasn't a dog until 3k rpm. Dave says they are not supposed to be like that. I will be interested in what you find after you adjust the ALDA.

[Ara T.]

Im sure the rear end gear ratio hurts the off the line performance but with 201 ft-lbs (bout 30 more ft-lb than om617,just looked it up) torque I just always expected more... im really curious on how it will feel with your alda adjustment. Im not sure where that 201 ft lb torque peaks but I am assuming it is at a low RPM (before 3K!), as per your typical diesel.

[Hatterasguy]

No the 603 really revs. From my seat of pants feel torque peak is about 3,500+/-. HP seems to build to just north of 4,500.

[pawoSD]

Sure the 603 may have 201lbs of torque, but at what rpm does it develop it? Also, how many lbs does it have "off idle", right in the initial take-off rpms of 700-1200ish? Maybe the 617 has more push at those rpms, it seems like it has quite a bit (mine shoves me back into the seat if I romp it). Perhaps with the different gear ratios between the cars, the different weights, and the different engine torque outputs at low rpms vs. those differences, the SD is superior in initial acceleration to the SDL's?


Idea: Lets get 5 people with SD's and 5 with SDL's to line up and floor it to a checkered flag, on video, that'd give us some real data on which ones lunge forward fastest.

[dieseldiehard]

I had a poorly performing 603 in the first '87 300D turbo I owned and after rebuilding the top end of the engine it was little better than before. I discovered that the turbo wastegate wasn't fully closing thereby allowing some exhaust to leak past at take off - that's when you need every bit of it to spool up properly. After cleaning the turbo outlet and wastegate flap it was a completely different car! Cleaning the intake manifold hasn't done anything for improving acceleration or performance but I can sleep better knowing its nice and clean inside the intake and crossoverpipe (and the egr is disabled to keep it that way!).
My 603 has never needed an ALDA tweak, and it gets up and goes! OTOH almost every 617 turbo I've seen can show improvement in acceleration with an ALDA tweak.

[Hit Man X]

Almost there, taking a break for some Adult Swim

Two glow plugs were sooooo overtorqued the threaded end was loose! I only had two working, no wonder the car started up like crap. Ran down to AutoZone and picked up six Bosch ones and installed them.

I had my Pops drive my SD and I drove the L, we raced from about a 50mph punch to about 70mph... the L starts to pull on the high end of the RPMs.

The SD w/ the ALDA maxed is FAR quicker off a dead stop right now now than stock and even the L.

[pawoSD]

Now that both are up to snuff and have their alda's tweaked, which is faster from a dead stop?