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Engine Specific Info and Questions => IDI Engine => Topic started by: boxer246 on March 11, 2008, 08:35:47 pm
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I guess this is more commonly referred to as the "smoke screw" right?
I know this has been covered before, but my searches have turned up not much, so here goes.
Basically, if you turn the screw in, you are sort of adjusting the "starting point" or baseline of the boost pin? So, by doing so, you are allowing additional fueling to be delivered earlier in the RPM range?
Ok, so if you adjust the starwheel so that the spring seat is lower, then there is less preload on the spring, therfore it takes less boost to move the boost pin, therefore making fuel come on quicker with less boost? So, if you adjust the smoke screw in, or downward, and move the spring seat lower, then in effect you will get more fuel starting sooner, and it will continue to build with less boost pressure than before?
Now, someone had a good write-up about the relationship between the max fuel screw and the boost pin movement, but I could not find it. If anyone comes across it please post it again. Otherwise, I'm not too sure how these two adjustments will affect one another, except to mess with them using trial and error.
Now that I have the motor running decent (1.6TD) it has somewhat underwhelming midrange performance. I realize some of this is characteristic of the 1.6TD what with the big T3 turbo....slow spool etc. But honestly I expected it to be significantly better than my NA in the midrange, but its not too much, if at all. To get things going, I have to really tromp the throttle and when the turbo spools, it makes power, but its on the high end....with my foot almost to the floor.
I cant be too hard on the motor just yet anyway because its fresh, and being broken in, and I have no EGT or boost pressure gauge yet.
The motor itself is stock, with the IP governor and advance mod done, head port castings cleaned up, intake manifold castings cleaned up, gasket matched, rebuilt turbo, stock injectors. Exhaust is 2.5 inch turbo back with hi-flow muffler.
Maybe a set of better injector nozzles, such as GTD's would provide for larger power potential in the midrange. I've never heard much about them.
An intercooler is next on my list of things to do.
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Don't forget you can remove the cover and rotate the boost pin to change the steepness of the cut, allowing more or less fuel in relation to boost. The smoke screw and starwheel just change how fast the fueling changes, but rotating the pin changes how much.
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Jim thanks for the input. I am going to mess with the pin...rotate it to maybe the opposite side of the eccentric, and see how that affects things.
Nobody with a 1.6TD has any comments on this? It would be helpful.
Jim hows your project coming? Did you get your IP figured out and engine running?
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i ground the hell out of my pin , the steepest setting didn't have enough fuel for my liking . even now i'm thinking i'll grind it a bit more .
i also bottomed out my starwheel , and turned the smoke screw up wards so the pin that rides on the ground fuel pin at the bottom of the fuel pin .
i also ground about 1/8 of a inch off the bottom of the fuel pin , to allow it to drop farther . i also shaved the white plastic washer on the fuel pin in 1/2 to allow it to drop down farther .
the whole idea was to increase max power , BUT also increase millage when just crusing.
i also blocked off my blow off valve on the intake , and turn up the waste gate for higher boost presure , which will force the fuel cone down father at max presure .
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Im pretty much in the same boat as you...1.6TD, T3 turbo etc. and am also quite underwhelmed by the slow spool/low-mid range power.
I have yet to make any mods to the pump (it decided to start leaking so that has to be fixed first :roll: ) so I can't really give you any 1st hand experience, but I am also looking for the right combination of pin/screw/wheel settings to make it spool faster. Let us know what you find!
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Burnt....I'm not sure I understand why you moved the smoke screw upwards, yet all the other mods you did were to make sure the pin was able to move downwards farther. When you say you still want more fueling, after all that, what makes you want more...in other words, do you think it isn't putting out enough at full boost? or medium boost? I guess you have little to no smoke?
How did these adjustments increase both economy and power....as you say? Maybe the increased fueling in the midrange area will allow boost to build better (or quicker), thereby allowing for a more complete combustion and better economy?
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Burnt....I'm not sure I understand why you moved the smoke screw upwards, yet all the other mods you did were to make sure the pin was able to move downwards farther. When you say you still want more fueling, after all that, what makes you want more...in other words, do you think it isn't putting out enough at full boost? or medium boost? I guess you have little to no smoke?
How did these adjustments increase both economy and power....as you say? Maybe the increased fueling in the midrange area will allow boost to build better (or quicker), thereby allowing for a more complete combustion and better economy?
what i did was increase the range that the fuel pin could move upwards , and downwards , meaning that at low boost it restricts the fuel more than stock , and at high boost dumps way more fuel than stock .....
maybe i should go take some pics , it might help ... brb :D
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(http://i272.photobucket.com/albums/jj199/regie131/IMG_0037.jpg)
(http://i272.photobucket.com/albums/jj199/regie131/IMG_0036.jpg)
(http://i272.photobucket.com/albums/jj199/regie131/IMG_0035.jpg)
(http://i272.photobucket.com/albums/jj199/regie131/IMG_0034.jpg)
(http://i272.photobucket.com/albums/jj199/regie131/IMG_0033.jpg)
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first pic shows the washer i cut in half
2nd pic , side veiw of my ground boost pin
3rd pic shows the range of movement all the way down to the tip of the pin
4th pic , shows the range of movment that i had before the mods , the wear mark is about in the middle of the cone .
the 5th pic compares a stock pin to mine , and shows how much i ground off of the foot . maybe more like 3/32 of a inch rather than 1/8 .
also be aware i'm also running 18 pounds of boost and a 2.5 inch exhaust , doing this to a stock engine might cause your egt temps to skyrocket .... watch how much black smoke your making , and adjust acordingly , or better yet get a egt gauge :D .
*edit * ... also see this thread too , http://vwdiesel.net/phpBB/viewtopic.php?t=645
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Burnt....thanks a bunch. I understand what you did. I'm just gonna play with it trial and error and see what happens.
I have no EGT gauge at the moment, but thats the next thing on my list. I have 2.5 exhaust and I also disabled the blowoff valve. I assume my turbo is only putting out 11 psi or so (or whatever they are wastegated to stock) because as of now I do not have a boost controller. I will probably install one after I put in a EGT gauge, boost gauge and intercooler.
I think my next step is to turn the star wheel down some then turn my smoke screw upwards a bit.
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What are thoughts on GTD nozzles? Anyone use them?
Would I only expect to see gains in higher end horsepower with those?
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What would happen if you removed the plastic washer??
My GTd spools up pretty quick and all i have played with is the fueling! Still need the boost turned up, just not sure how to do it at the moment!
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get rid of the plastic washer......
ive found that having the smoke screw in too far really killed my mileage
yea turn it in some(i think mines in like 1.5turns),but more to be had by completely bottoming the starwheel,and adjusting the pin(or cutting like you)
get an extra starwheel spring and do the lowrider trick: heat it cherry red man....has a similar effect as the smoke screw if you think about it,and since its weaker,itll go full fuel with minimal boost anyways
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yep
i used sandpaper wheel on my dremel,then a felt polisher wheel with some toothpaste(crest is great polish) :wink:
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the plastic washer acts like a cushion when the pin is driven downwards , i wouldn't recomend removing it .
as you can see my pin isn't being pushed all the way down any way by boost presure , so the next best thing is to grind deeper into the pin where the small pin rides on the fuel pin , allowing more fuel in the range that the small pin rides on the fuel pin .
and yes after your done grinding , it has to be polished smooth .
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Here a fun pic to show the pin inside a real pump:
(http://i19.photobucket.com/albums/b166/9golf1/boost%20pin/Photo012.jpg)
(http://i19.photobucket.com/albums/b166/9golf1/boost%20pin/Photo011.jpg)
Here now a different lengh of the feeler pin (guide pin), the longest allow more fueling on-boost with proper boost pin or proper boost pin grinding.
(http://i19.photobucket.com/albums/b166/9golf1/boost%20pin/guidepinlda.jpg)
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the plastic washer acts like a cushion when the pin is driven downwards , i wouldn't recomend removing it .
as you can see my pin isn't being pushed all the way down any way by boost presure , so the next best thing is to grind deeper into the pin where the small pin rides on the fuel pin , allowing more fuel in the range that the small pin rides on the fuel pin .
and yes after your done grinding , it has to be polished smooth .
mines been with no (plastic)washer for years...my pump guy told me its ok to remove it for better pin travel,etc
its not like its hammering itself on the top of the pump casting or somethin
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Here a fun pic to show the pin inside a real pump:
(http://i19.photobucket.com/albums/b166/9golf1/boost%20pin/Photo012.jpg)
(http://i19.photobucket.com/albums/b166/9golf1/boost%20pin/Photo011.jpg)
Here now a different lengh of the feeler pin (guide pin), the longest allow more fueling on-boost with proper boost pin or proper boost pin grinding.
(http://i19.photobucket.com/albums/b166/9golf1/boost%20pin/guidepinlda.jpg)
nice, i was also thinking to build something like that, to adjust the pressure very good, becouse otherwise you cant know when the lda is down at what boost.
this is very very intrested information tintin!
So if you put a longer feeler pin, can the other parts in the VE also support more advance?
(http://img232.imageshack.us/img232/7818/speedcontrolkw8.jpg) (http://imageshack.us)
Greetz, Benjamin
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Does anyone have any links / info on tuning my stock uk 1.6GTD Mk2 golf - Here is the spec
SB code engine 80bhp
Intercooler mounted in engine bay on slant
290,000 miles
45-48mpg
0.7 Bar boost pressure
I'm after reliable power increase that can be used every day and still return a decent miles per gallon. ANY ADVICE OR LINKS would be appreciated
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K77aus......here's the best info:
http://vwdiesel.net/phpBB/viewtopic.php?t=645
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I just got around to turning the boost pin to the steepest ramp in my 1.6TD and I'm glad to say it made quite a big difference. More power overall but more importantly, the turbo spools sooner and faster giving me a usable midrange. I also cut the plastic washer in half to allow more travel and I cant say I noticed a difference. It still doesnt smoke much and the EGT's are under control so theres room for more and I'd still like to get better spool/midrange power. My next mods will be turning the max fuel screw in to up the fuel over the entire range, turning the starwheel down to allow more fuel sooner in relation to boost, and turning the smoke screw up to allow the starting point to be close to stock for better economy.
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right now , with my car , at 18 pounds of boost , and the softest vw boost diaphram spring i could find locally ( it's blue / greenish ) , and the star wheel all the way down , i'm not bottoming the pin in side the housing yet .....
so i suspect cutting the washer in 1/2 won't be of benifit until much higher boost pressures are reached ( meaning a metal headgasket and arp studs ) .
grinding the fuel pin will achieve more fuel at any given boost level , and spooling the turbo up much much faster than the steepest stock setting .
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grinding the fuel pin will achieve more fuel at any given boost level
As far as I understand, thats what the max fuel screw adjusts. I would rather play with that than grind my pin because its easier and fully reversible.
You may be right about the washer though...I will do some testing and calcs to figure out the spring constant so I can graph the boost pressure vs fuel pin position.
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RE: removing the washer.
Would it not be a good idea to replace the thick plastic washer with a small rubber o-ring, that way you still have some cushioning and increased travel.
just a thought.
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something i'm just now realising , unless your making over 30 pounds of boost ( like a cummins engine ) , there isn't enough presure even with the softest vw diaphram spring to bottom out the fuel pin .
so cutting , removing or replacing the plastic washer does nothing till you reach the higher boost levels .
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something i'm just now realising , unless your making over 30 pounds of boost ( like a cummins engine ) , there isn't enough presure even with the softest vw diaphram spring to bottom out the fuel pin .
Just wondering how you are figuring that?
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something i'm just now realising , unless your making over 30 pounds of boost ( like a cummins engine ) , there isn't enough presure even with the softest vw diaphram spring to bottom out the fuel pin .
Just wondering how you are figuring that?
just watching the marks in the grease on the pin , and figuring out how far it travels downward . with a greenish blue spring ( the lightest vw spring i've found so far ) the 20 psi peak my turbo hits isn't bottoming the pin .
to counter the pin not bottoming , i ground a deeper taper into the pin
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RE: removing the washer.
Would it not be a good idea to replace the thick plastic washer with a small rubber o-ring, that way you still have some cushioning and increased travel.
just a thought.
Now I'm not bashing you with this comment Mr Brick I just need to do say something.
I've read more than once here that people (may only 2) are concerned about removing the plastic washer..
Lets look at that for a sec shale we?
First off there is never enough force in there to do any harm with the washer removed. I do not believe it's purpose is cushioning. If anything its there to limit travel.
The plastic washer moves the pin farther down at the no boost setting due to the thickness.
If it's removed the pin sits higher at no boost thus a tad less fuel till boost builds. If you leave it there you have that very little bit of more fuel off idle.
What I did was to remove it and install a metal washer in it's place that was the same DIA as the pin so it would have more travel, maybe only 2mm at the most but we are talking about mm of adjustment here anyway.
I custom ground the pin to have a more aggressive slope and I removed some material from the bottom as well as the pin was hitting the bottom of its travel and not using the full ramp.
this gave me more usable fuel on the top end.
I hit 30psi all the time so pressure isn't a issue with me as to spring pre load. I have the pre load on the spring turned way up to the top so it's really still so it smokes less at low rpms. Once I'm rolling and the boost hits past 5 psi I can fell the fuel increase allot more.
Goes from 5psi to 25 FAST.
I'm thinking of grinding another pin with a mild slope the first 1/4 of it maybe then a aggressive slope after that so my usual around town driving is less smoky until I mash it and once it hits the steep part of the slope it will dump more fuel in..