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Need to turn down the smoke
by
sdwarf36
on 08 Nov, 2011 23:27
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My rebuilt TD is running great. The Giles pump works awesome-maybe a little too good. Under partial throttle-say accelerating from 1/8 to 1/4 throttle in traffic-i get a fair amount of smoke. (Enough to see in the headlights of the car behind me. ) People stuck behind me in my commute had to put up with blue smoke out of my used up NA for years-doubt they feel any better now the smoke is a different color.
Which screws do I turn to decrease the smoke? If i lose a little bit of power, I can live with it. I can always curl my toes + push the pedal down farther.
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#1
by
maxfax
on 08 Nov, 2011 23:57
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The one circled in red.. About 1/4 of a turn at a time is the best formula... CCW decreases the fuel.. You may have to bump the idle up a tad, pending on how much you adjust...
Before going too far, you may want to contact Giles and make sure he doesn't have any other suggestions.. Remember that this screw will decrease fueling across the board..
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#2
by
ORCoaster
on 09 Nov, 2011 00:07
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What a great pic and description. I think most new and some old members need to burn this pic into their brains. It is a constant source of discussion here. ?A sticky?
I have found that sometimes 1/8 turns are better once you overshoot the desired fueling curve you want. Bring it back half the distance each way and you can zoom in pretty quick to where the best point is for your particular engine. Yes it will be different for all of us. Wear and age being the different factors.
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#3
by
maxfax
on 09 Nov, 2011 00:24
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You know, now that I think about it, there are quite a few posts about the fuel screw, and no real easily linkable threads for it.... Taken care of in the FAQ.. I'll add to it as I get time.. I guess the internal pressure adjustment might be a good addition.. Any other suggestions? If it is something covered in a nice clean linkable thread make a note of it in there..
Sorry to threadjack sdwarf36 ..
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#4
by
sdwarf36
on 09 Nov, 2011 01:02
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Sorry to threadjack sdwarf36 ..
No problem!I was a good doobee + searched 1st-didnt find anything complete. I'd love to see 1 place where it showed what can be adjusted- and which direction to turn the screws.
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#5
by
ORCoaster
on 09 Nov, 2011 13:17
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OK more thread jack since this has spurred us to action.
It seems to me that this screw is just one of a few that constantly get referred to here on the forum. I would say that yes the pressure regulator screw is another and that was posted several times here.
The adjustments for idle whether it be the simple stud and nut on early model IP's or the more sofisticated idle bump/ cold start lever.
Finally there seems to be a picture posted on this forum for what bolts hold the IP in place. That was clearly displayed somewhere. If an addition for direction of rotation that produces advance or retard I think that would help a lot of beginners that don't necessarily have a Bentley or can read it.
Hope these get added on. I also would just include some of those graphics that show an expanded pump or flow through a pump those have been here as well.
Just my 2 cents less one.
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#6
by
MJF
on 09 Nov, 2011 13:30
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I smoke boost related? Maybe LDA spring adjusting would help?
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#7
by
R.O.R-2.0
on 09 Nov, 2011 13:31
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1/8 - 1/4 throttle shouldnt have much boost present.
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#8
by
sdwarf36
on 09 Nov, 2011 20:27
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So what does the screw on the LDA adjust? And which way is richer-which way leaner?
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#9
by
ORCoaster
on 09 Nov, 2011 21:26
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I will have to defer to one who knows. I don't have one on my 81.
And VW happiness is wing windows that seal and open. might need a thread or a poll.
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#10
by
Luckypabst
on 09 Nov, 2011 22:44
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LDA screw allows you to tune the initial position of the boost pin. In order to see the full range of LDA enrichment, you want the follower pin resting on the largest diameter of the taper at zero boost without also contacting the step adjacent to the ramp.
Chris
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#11
by
maxfax
on 10 Nov, 2011 00:28
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ORcoaster, Good ideas.. I did some searching and Tyler does have a post in the FAQ about pump mounting and timing.. I'm going to link to it.. I'm not real up to speed with internal pressure adjustment and LDA's as well as idle adjustment on those fancy pumps.. I got a bit of homework to do I guess..
I know all this info is out there, but it seems to be so scattered around in several different threads.. Me personally, I get impatient when trying to find stuff at times... Imagine how it must be for a noob.. EVen the FAQ has a lot of short little bits of info that woudl be ice to have combined....
LDA screw allows you to tune the initial position of the boost pin. In order to see the full range of LDA enrichment, you want the follower pin resting on the largest diameter of the taper at zero boost without also contacting the step adjacent to the ramp.
Chris
Chris I'm stealing that..
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#12
by
vanbcguy
on 10 Nov, 2011 02:25
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To be clear... what you want is what's right for your boost / rpm range / etc.
Max fuel that's set too high and an LDA that's set too aggressive will smoke all the time. An overly aggressive LDA with the fuel turned down will make you stumble till boost comes on, and can even have you set up with smoke clouds at the top end but in the doldrums on the bottom. The 'biggest' ramp is not always the best with the LDA, hence why it has an adjustment to narrow down the difference between "initial" and "max" plus adjust the minimum boost required to move it.
Sometimes you DO want lots of fuel at the low end to get your engine up to speed, but don't want to be billowing clouds once the turbo is spun up! Remember the LDA's purpose as far as Bosch is concerned is to reduce smoke output by limiting fuel till there is enough boost to use it. If it's set too aggressively then you're just going to exaggerate your turbo lag...
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#13
by
sdwarf36
on 10 Nov, 2011 12:12
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Ok-so which way do you turn the torx screw on the LDA for more/less fuel? Its also my (not full) understanding the the pin on the LDA is offset ground-how do you tell which way its facing? Is 1 full turn equal to a 1/2 turn where it goes from low spot to high spot on the pin?
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#14
by
Luckypabst
on 10 Nov, 2011 12:24
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You probably need to pull the pin to see. You can estimate high side vs. low side pretty accurately by eye, then make a reference mark on top. You only get a half turn out of the pin... once you pass the halfway point you start heading back to where you started.
The screw in the LDA cover doesn't simply add fuel; as I said earlier, it tunes the position of the boost pin. In theory, you want to have available the most range from large diameter to small diameter of the boost pin. To achieve this, the initial position of the pin needs to be at a point where the little follower needle rests on the largest diameter without also crashing into the step (see the MOAR POWA thread for a photo of stock boost pin). You can also think of the initial position of the boost pin as controlling the upper limit of off-boost fueling, same as the fixed stop in a NA pump. As boost increases and the pin drops in the LDA, the upper fueling limit is extended, allowing enrichment to support the turbo.
Chris