Tutorial: tuning the 4D56 for more power.

2 Questions...

Growlerbearnz said:
Boost Tee (as in mechanical boost controller) goes into the wastegate line, yes, but the boost gauge goes in the other line- the one from the turbo to the injection pump.
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First question - Where do you mount/leave the Mechanical Boost Controller? When looking to install this boost controller in my Delica, I realized that the wastegate line is not "easily" accessible to access, since I'd need to remove the air cleaner cover, driver's seat, parking brake handle, gas cap release, the frame seat, etc... JUST to adjust the boost? So, was thinking I should use longer vacuum hoses to move it closer to the main engine cover. Thoughts on that?

Second question - I know that the 4D56 and the D4BF are "mostly" identical... So, would the tuning steps be the same?
 
Most of the tuning is adjustments of the IP, and they are all running the same basic Bosch VE type... should be the same.
 
When I had a pneumatic boost controller I extended the boost lines and cable tied the controller to the plastic intake pipe in the air filter area. Relatively easy to get to (scoot seat forward, remove cover panel). If you leave the cover off it's fairly easy to adjust while driving, especially if you make the hoses long enough.

The tuning steps are identical on the D4BF.
 
@sck_nogas
I extended the lines on a 04' turbo miata and put the boost controller dial in the engine compartment so it was relatively easy to access when tuning. I knew folks using the same system but routing the dial into the cabin so it was adjustable on the fly. Didn't trust myself with that. :)
 
I got into things and decided to give this a try. Although once I got in there I found that my star wheel was wound down to 25mm. Why would that be? I backed it off to 12mm. Everything seems to run fine now. So why would it have been so wound down?
 
Jgrant0553 said:
I got into things and decided to give this a try. Although once I got in there I found that my star wheel was wound down to 25mm. Why would that be? I backed it off to 12mm. Everything seems to run fine now. So why would it have been so wound down?
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I'd guess someone was trying to get more power out of it, but didn't quite understand how the IP works (or didn't know about how the different adjustments interact). Did it belch black smoke when starting off? A star wheel that's too low means a small amount of boost (like when the turbo's just starting to spool up) would inject too much fuel, causing black smoke. If it's *way* too loose it can cause the diaphragm to move around when the engine's idling, which leads to puffs of black smoke and an unstable/rough idle.
 
Growlerbearnz said:
I'd guess someone was trying to get more power out of it, but didn't quite understand how the IP works (or didn't know about how the different adjustments interact). Did it belch black smoke when starting off? A star wheel that's too low means a small amount of boost (like when the turbo's just starting to spool up) would inject too much fuel, causing black smoke. If it's *way* too loose it can cause the diaphragm to move around when the engine's idling, which leads to puffs of black smoke and an unstable/rough idle.
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No it seemed to run just fine, but I was never able to get the EGT to even out on a climb, they would just keep climbing. I can’t take my idle screw down to 10mm the arm would never touch it. The high speed screw was already at 6mm. The EGT seem better now and I can find a happy place climbing hills at speed and level off the EGT. I adjusted the idle with the screw on the back of the ip. Only thing now is that when I’m at idle it seems to be a bit more clatter. Once I’m on the gas it sounds great. Is that normal? Would taking my boost up to 14psi give me much cooler egt? I’m at a even 12psi now, can’t seem to pull anymore out of the waste gate adjustment.
 
Jgrant0553 said:
1) I can’t take my idle screw down to 10mm the arm would never touch it.
2) I adjusted the idle with the screw on the back of the ip.
3) Only thing now is that when I’m at idle it seems to be a bit more clatter. Once I’m on the gas it sounds great. Is that normal?
4) Would taking my boost up to 14psi give me much cooler egt? I’m at a even 12psi now, can’t seem to pull anymore out of the waste gate adjustment.
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1) ...because the accelerator cable is holding it back? You need to adjust your accelerator cable then; Step 5. See how my accelerator cable is adjusted as long as it'll go? Unless your accelerator cable is already as long as it'll go, then that's your limit.
Or is the AC idle-up solenoid arm holding it back? again, adjust as needed.

2) If your idle screw is as low as it'll go, that's the way to do it. Though it's a good idea to adjust your idle to 650rpm that way and use the idle screw to bring it back up to 750- that'll give you some adjustment in future without having to adjust the main fuel screw on the back of the IP (which is a hassle).

3) It'll clatter more if you've adjusted the timing (bonus points! but risky if you go too far). It shouldn't clatter more if all you've done is adjust the fuel but retained the original idle speed. You might also be paranoid, listening to the engine harder than usual ;-). But no, a bit of clatter at idle that goes away at higher revs isn't a problem.

4) Not *much* cooler EGTs, but some. Turning it up to 14 also makes the intake charge hotter, which can negate power gains if the engine's really working hard. Going above 12psi is a hassle anyway- you have to remove the blowoff/overpressure valve and fit a boost controller.
 
Yea the throttle cable is holding it back, I’ll go back and lengthen it, didn’t think to do that. Didn’t touch the timing, don’t need bonus points. Maybe clatter is a bad word for the sound, but it’s only there at idle.
 
More tuning more questions. I lengthened the throttle cable and that gave me more room to run out the idle screw. This helped a bit, I also turned the diaphragm away from the front of the engine a bit to ease the smoking and help the EGT stay lower.

1 I’m having trouble with the idle. It is either to low or to high. If I set it to 750 with it in natural as soon as I put it in gear it drops way down to 650 and shakes really bad. I put it back in park and it comes back up to 750 then jumps up to a 1000. Any ideas?

2 is there a base line for normal EGT. It seems like mine climb really fast up to 1200 then I have to take my foot out of it, hard to get them to level off and keep speed up even a small hill.
 
The tuning in the original post has made my Deli run MUCH more smoothly up here in the Colorado high country. Yes, it's still only 88 hp, but it doesn't run out of puff up high, EGTs are down in the safe range while working hard (1,280°F post-turbo, down from 1,500°F), and doesn't leave a smoke trail anymore. I did turn the boost up to 14 psi by shortening the wastegate linkage. I'm getting some occasional sudden loss of boost at full throttle (sudden drop down to ~10 psi on the gauge, along with a psssst sound from down below, and a drop in power, with recovery within a second), but I believe that's because my boost gauge isn't hooked up fully tight. I need to get my hands on some tiny hose clamps.
Thanks to the OP!
 
mattyk2 said:
EGTs are down in the safe range while working hard (1,280°F post-turbo, down from 1,500°F),
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Err, I hope you mean "pre-turbo", as in measured at the EGR blanking plate? 1280F post-turbo is probably somewhere near 1400F pre-turbo, which would be *way* too hot. You never want to go beyond 1400F pre-turbo, or even hold 1400 for too long: the exhaust turbine will melt/weaken/explode.

mattyk2 said:
I'm getting some occasional sudden loss of boost at full throttle (sudden drop down to ~10 psi on the gauge, along with a psssst sound from down below, and a drop in power, with recovery within a second),
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That sounds like the overboost relief valve. It's designed to open around 13psi to let "excess" boost out. If you're running more than 12psi you need to disable the relief valve. http://delicaforum.com/index.php?threads/turbo-related-noise-waste-gate-idk.1457/#post-11024
 
Jgrant0553 said:
More tuning more questions. I lengthened the throttle cable and that gave me more room to run out the idle screw. This helped a bit, I also turned the diaphragm away from the front of the engine a bit to ease the smoking and help the EGT stay lower.

1 I’m having trouble with the idle. It is either to low or to high. If I set it to 750 with it in natural as soon as I put it in gear it drops way down to 650 and shakes really bad. I put it back in park and it comes back up to 750 then jumps up to a 1000. Any ideas?

2 is there a base line for normal EGT. It seems like mine climb really fast up to 1200 then I have to take my foot out of it, hard to get them to level off and keep speed up even a small hill.
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1)Yeah that's a thing that happens. I've not had it happen personally, but I know of a couple of people having issues. At this stage I think it's because the idle position is too far back- the IP's little internal spring that connects the throttle lever to the governor is probably loose. Try turning the idle screw back in around 5mm, then adjust the fuel screw to bring the idle back down. Let me know if that makes the idle stable.
2) Pre-turbo EGT (in the EGR blanking plate): yours sound normal for a slightly tired engine. It'll sit around 1000F, but once you start climbing it's easy to give it too much accelerator and it'll shoot up to 1400F if you let it? That's the consequence of tuning- more power, but also more responsibility (there's probably a saying in there somewhere). It's your job to keep the engine from asploding. For the record it'll do 1200F all day long, 1300F for short periods (30 seconds or so? Maybe a minute?) and 1400F is the absolute upper limit. If you find you're accidentally shooting past 1400F often, turn the tuning down a bit.
 
Growlerbearnz said:
Err, I hope you mean "pre-turbo", as in measured at the EGR blanking plate? 1280F post-turbo is probably somewhere near 1400F pre-turbo, which would be *way* too hot. You never want to go beyond 1400F pre-turbo, or even hold 1400 for too long: the exhaust turbine will melt/weaken/explode.
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Ugh no, definitely post-turbo; My EGT probe is down below the turbo exit, where it meets the exhaust. I'd do the EGR blanking plate for the probe, but I kinda gotta leave the EGR in place for emissions here in metro Denver.
Well, now what? I've been running these temps for a while whenever climbing hills here in the high country. What's the next step to lower EGTs?
 
Growlerbearnz said:
For the record it'll do 1200F all day long, 1300F for short periods (30 seconds or so? Maybe a minute?) and 1400F is the absolute upper limit.
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I think (hope) that's conservative. Quoted from the link to Banks Power:
"So the big question is, what constitutes excessive EGT? If everything is working properly, 1250º to 1300º F. is a safe turbine inlet temperature, even for sustained running, mile after mile. Above 1300º F. things can start to get edgy. Over 1400º F., you’re usually gambling against a stacked deck and it’s only a matter of time until you lose. The higher the EGT, the shorter that time will be."

At 1200 (650c) my coolant gauge stays around 1/4, and I basically have to be coasting to see it much lower than that. Since I've gotten my van I've let it run at 1300 (700c) w/o concern unless I see the coolant temp rising above half (and it takes quite a few minutes to get to 1/2). I have my alarm set at 1400 (750c) and have hit that momentarily, but I try to avoid it and try to prevent the turbo from heat soaking to that temp.
Not long ago I inspected the turbo and found no signs of excessive wear/melting/fatigue. I've been driving it like this for 3yrs now; I live around mountains, it's almost unavoidable. When operating at the higher temps it seems to require almost no throttle movement to cause the EGT to spike 50*c.

I have seen a lot of more conservative recommendations, but not from people who's business is actually making and tuning turbos. I'm pretty sure most of these vans would have self detonated well before reaching 25yrs old and finally having an EGT gauge installed if it was that critical ;) . But I'm NOT recommending anyone run their van as hard as I do... they are old vehicles, and even if the turbo survives that doesn't mean something else isn't going to give up.
 
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sk66 said:
Let off the throttle...
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As if the line of traffic behind me wasn't bad enough...
Well, I'll try to take it easier on her. Good thing about the tune is that it brought temps down all around, so hopefully that'll contribute to longer life (to offset the relative thrashing she gets now and then).
For the record, I've tried the fueling diaphragm in both 90° and 180° away from the stock position.
0° (stock) = smoky all around, EGTs obscenely high.
90° = 200°F cooler, almost no smoke
180° = not quite as cool (but still way better than stock), a little more smoke, not as eager to rev.
I might try 135° next, or just go back to 90°.
 
BTW, those temps I mentioned are header temps pre-turbo. At full load post turbo temps will be 200-300*f lower, so subtract 200-300.

If you run a turbo with too high of an EGT the turbine fins start to melt, it then becomes unbalanced and eats itself. High EGT's also mean higher combustion temps, and if they are too high you can also burn a hole in a piston... especially the aluminum type used in these engines.

I would tune for the lowest EGT's... that equates to the greatest efficiency.
 
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