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Engine Specific Info and Questions => IDI Engine => Topic started by: Jcolussy on January 08, 2011, 05:45:09 am
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I have a 91 Jetta I added a turbo to and now I need more fuel I got my N/a pump turned up as much as i can and am using the lda on the n/a pump that was worked by vacum before as an lda controlled by boost now by running boost into the top of it. Will a TD pump beable to put out more fuel I didnt know if it had a bigger injection pump head or not to deliver more fuel.
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probably not, the thing that i think would help you is a td boost pin, or just to grind a more agressive ramp on to yours
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n/a pump is capable of more fuel at lower RPMS, so ive been told by many reliable sources.
i actually prefer the n/a pump on turbo applications.. i hate waiting around for the turbo to spool so i can have full fueling..
my right foot does every bit as good of a job as that LDA does.
it just seems like the turbo lags more with the LDA.. my VNT spools considerably quicker with a n/a pump.
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The LDA pumps and non-turbo pumps have the ability to pump the same amount of fuel at the various rpms. There is no downside to an LDA pump. The LDA pump is far more tunable and more efficient. A properly tuned LDA pump will cause the turbo to spool as fast as a non-turbo pump and yet will vastly reduce smoke and fuel consumption. Unless you are running MASSIVE amounts of boost, then you have not maxed out your pump. Read this thread:
http://www.vwdiesel.net/forum/index.php?topic=21600.0
Your altitude compensating pump has all the workings of the TD pump aside from the boost pin, as mentioned.
off boost, just off idle, tell me how the TD pump is gonna supply as much fuel as the n/a pump? there is no boost to push the pin down and make the pump go to full fueling..
my LDA didnt start rockin till about 10 PSI..
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Andrew ftw ;) I admire your cranium good sir lol.
That's what I had heard too about the pumps being as capable as each other.
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Do you have an EGT gauge? In my experience a NA pump at or slightly above stock fuelling settings can deliver enough fuel to get your EGTs into the danger zone on a NA-TD conversion. This is because the NA motor has a low restriction exhaust, and when you add a turbo, you are greatly increasing the exhaust restriction, so even at stock fuelling settings on a NA pump you can create very high egts at low boost conditions. This is my understanding anyway, and experience from my NA-TD conversion.
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Right now I have a 2"mandrel bend exhaust with magnaflow muffler and gov-mod IP. I am thinking of going turbo, but was wondering if I left the IP as it is now, and slapped on a turbo with about 10PSI max, would I even notice a difference in acceleration and top-end? I figure with more air being introduced with the stock fueling, my EGT's should be lower because I am getting more of a complete combustion? I like my NA motor, but wouldn't mind better acceleration, better mpg's, and better hill climbing, I just don't want to mess with the IP settings, but do you have to if one decides to go turbo? What would happen if you didn't mess with the IP settings?
Thanks
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Depends on the turbo you use. I stuck a stock K24 on a NA, with stock injector pump, and it didn't produce much boost unless I really hammered it. Fun for those days I wanted to drive like a maniac, but not much use in normal driving.
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ROR, it all depends on how it is tuned. The boost pin is just an adjustable pivot point where the non-lda pumps have a pin. You can get the same injection quatities as the non-lda pump for any static position for that pivot. You can tune an LDA pump so that it pumps big black billowing clouds right off idle. In other words you can tune it to supply utterly ridiculous amounts of fuel without the boost pin having moved. You could disconnect the lda altogether and adjust it to perform the same as the non-turbo pump.
i stand corrected..
there are just some people on this forum i will not argue with.
Andrew, Vincent, and Tyler spring to mind first..
you guys have never fed me ill information..
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Do you have an EGT gauge? In my experience a NA pump at or slightly above stock fuelling settings can deliver enough fuel to get your EGTs into the danger zone on a NA-TD conversion. This is because the NA motor has a low restriction exhaust, and when you add a turbo, you are greatly increasing the exhaust restriction, so even at stock fuelling settings on a NA pump you can create very high egts at low boost conditions. This is my understanding anyway, and experience from my NA-TD conversion.
if you choose to hook the stock exhaust up to your new turbo engine.. i would never hook 1.25" exhaust up to a turbo, thats asking for loads of back pressure.
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Thanks for all of the replys as of now i am going to grind the boost pin and see what difference that makes thanks
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FWIW, my n/a pump puts out LOADS of fuel.. i have it relatively turned down, considering that it has like 2 or 3 full turns left on the fuel screw, and still be able to idle.. never drove it around turned up that high, but i know it would free rev and return to idle with it cranked up that high tho.
i always wondered what it would be like to throw my LDA onto my n/a pump body.. should operate just like a TD pump then.
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it seems like my current n/a pump puts out more fuel than my LDA pump did. and my lda pump had no fuel limiter pin.
does that pin really even have a function on these little engines? cause i have more fuel than i could ever burn with the pin still in my n/a pump. it would smoke black something fierce.. i think it has something to do with the fact that the pump has about 20k miles on it, and my last one was a conglomeration of pump parts. theres no way the pump i built runs as good as this pump on my car now.
(im not arguing with what you said either)
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So is it worth it to go turbo with a 2" mandrel bend exhaust with magnaflow and gov-mod IP? Will I even feel or see a difference? What turbo is a good one to put on just for stock/mild upgrade, nothing crazy!?!
-Thanks
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ROR, the pin is not a fuel limiter, it is a pivot point for the control collar lever assembly. It serves the same purpose as the lever that comes down from the LDA except it is not adjustable like the the LDA lever is according to boost pressure.
A good experiment would be to install your LDA pump, jumper the accelerator lever as outlined in that linked thread and along with the adjustment of idle and max fuel I think you'd find that the LDA pump puts out just as well.
As an aside, I don't mind disagreement or inquiry. It's how we all learn. I've personally learned more from disagreeing with people and then inquiring until I understood their viewpoint than I ever have from agreeing.
you know Andrew, im glad you can argue with people to prove a point or from a learning stand point. and still keep your head cool..
and the pin we were talking about, isnt it in the front (side) of the pump, by one of the 3 sided bolts holding the fulcrum plate in the pump? doesnt the fulcrum plate actually stop on that pin?
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Right, more of a stop than a pivot.
But the lever it stops, changes the pivot point of the lever the accelerator hooks to.
The pin is replaced by a moveable stop on a TD pump.
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Right, more of a stop than a pivot.
But the lever it stops, changes the pivot point of the lever the accelerator hooks to.
The pin is replaced by a moveable stop on a TD pump.
That's what I always thought too......
I don't have an LDA or the pin, even turned all the way in it wasn't that black. The other day I was getting stuck and tried 2nd gear floored, it bogged real bad (I have really good tires :-\) and when I looked in the side mirror I couldn't see anything but blackness. I had a slight tailwind so it was blowing past me for a couple minutes. During that the egt's where actually dropping.
All that to say it seems easier to overfuel at low rpm than at high revs.
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Right, more of a stop than a pivot.
But the lever it stops, changes the pivot point of the lever the accelerator hooks to.
The pin is replaced by a moveable stop on a TD pump.
That's what I always thought too......
I don't have an LDA or the pin, even turned all the way in it wasn't that black. The other day I was getting stuck and tried 2nd gear floored, it bogged real bad (I have really good tires :-\) and when I looked in the side mirror I couldn't see anything but blackness. I had a slight tailwind so it was blowing past me for a couple minutes. During that the egt's where actually dropping.
All that to say it seems easier to overfuel at low rpm than at high revs.
i cant over fuel over 2k prms. unless i crank my pump up to "maximum blackness"
its kinda funny driving around in the snow tho.. open downpipe.. lugging around. blip the throttle for a second and leave soot trails on the snow.. lol. downpipe comes off the turbo, and just directs the exhaust downwards. lugging it in 4th gear it will make a pretty decent streak.
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yup. i love having a smoke screen for tail gaters..