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Engine Specific Info and Questions => IDI Engine => Topic started by: scrounger on November 10, 2021, 01:28:06 pm
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Looking at part of my car that I can not see normally. I think this vacuum diaphragm is the waste gate control (Without a line from the intake manifold.)
(http://www.veloliner.com/vw/vwtdwastegate.JPG)
So theoretically I should be having maximum boost. No?
Pardon the greeb.
The pic was made with a cell phone against the firewall.
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Yes without any boost line on there you should be at max boost unless, someone fiddled with the adjustment on the control rod and has it kinda sorta open. Try putting an air line on it and giving it a shot of air at say 20 lbs and see if the rod moves at all.
Engine off for this one.
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Okay, sounds like a plan.
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I'm not sure that's a barbed fitting on the end of that vacuum can.
Looks more like an adjuster screw.
Could be wrong, it's dirty.
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Where would the boost come in on something like that? From the side of the tapered can? Maybe underneath?
Maybe another picture from the end view is needed to decide on that.
Scrounger, get back under the hood.
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(https://i.imgur.com/ORK0mASh.jpg)
Red circle is the adjustment screw.
Green arrow looks like it is the metal line fitting that runs to the intake scroll and is the boost supply to the wastegate.
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I guess they put these controls where they do, to keep us from adjusting them. The pic in Bentleyseems to show a vaccum line at the end of the pot but the intake tube to the turbo has one less fitting.
Gonna clean up and study some more.
Thanks for all the help fellow VW TD enthusiasts.
I tried participating on vortex and there was not the td knowledge that there is here.
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I assume you are talking about the pic of the turbocharger in the A2 Bentley. That shows the T3 turbo which has the connection as shown in that Bentley pic. You have a K24 or K14 (can't tell from the pic but probably a K24). The K24 has a metal line coming off the side of the wastegate actuator and running to the intake scroll.
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Hi Libby
yes the pic in Bentley
(http://veloliner.com/vw/vwwastegate.JPG)
Doesn't seem to reflect what my car has. The first thing that I saw was that the fitting in the pic is not centered on the diaphragm
I understand that one book could have every diagram of every setup,
Will look for that metal boost line.
tks
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Libby and Fat
Spot on. There is metal line from what looks like on the other side of the diaphragm and goes to a banjo bolt on the passenger side of the compressor impeller, so K24. Thank much.
(http://www.veloliner.com/vw/wastegateadjuster.JPG)
6mm stud, 3mm hex, probably a 10mm lock nut.
Now to make a tool to fit the lock nut and figure out which direction to turn it to make the boost go up some at max. Has 7-8psi now thinking that 10psi might be where it should be,
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Adjusting that is *not* a good idea. It is not an effective way to control boost. Cut the metal line and add a manual boost controller if you want to increase boost above stock.
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I had put a homemade pneumatic boost controller on my 300D . Used a brass T, two barbs, cap. steel bearing and spring. I used washers as spacers to control boost.
Welded up a handle on 10mm socket, turned the screw in a turn. I think that is the right direction. Have not had a chance to run the car.
Will keep your comments in mind. Thanks
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I have a bit more time now so I thought I would elaborate.
That screw will make a very slight adjustment to the pressure of the wastegate spring but that screw is also the stop for the wastegate valve. You will not get more than 1 or 2 psi of adjustment before the screw has moved far enough IN that it limits the movement of the wastegate valve too much. The result is that you will get an uncontrolled high rpm boost spike.
Instead of adjusting that set screw and messing up the open position of the wastegate valve, it is a much better idea to add a manual boost controller. I prefer the ball/spring style. That style of MBC is adjustable and will prevent the boost pressure from reaching the wastegate actuator until it exceeds whatever pressure the MBC is set to.
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Yeah, a pound or two may be fine.
At least I know how much It is turned and can be returned to the original position. i drive this car only every couple of weeks Am going to use it next week so will have a data point.
On the pop-off valve across the intake side of the turbo, I had to turn the screw in until it was seated for one psi going from 7 to 8. turning the same screw out all the way it went down to 6. Putting a plug in it didn't go any higher
The exhaust on my car has a tiny downpipe so am limited at how much it will do.
Not trying to make a world-beater out of it.
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If you start down the road to a better performance then start saving your pennies for a larger diameter downpipe. I have a 2.25 on the other side of the turbo on mine and run that into a low-back pressure muffler.
No amount of boost is going to be able to escape from that 1.5 diameter pipe without having to work at it. If you calculate the increased capacity between the two sizes it will surprise you.
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For sure ORC. Not much of a world beater, mine.
Hard to build boost without a pressure drop.
It actually runs okay now but thought maybe just a little more.
I found through experimentation that bigger bore exhaust is great for high rpm numbers but throttle response and low end are quite another, besides I just put a new headpipe on last summer. :)
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It's either a k24 or a k14.
Boost is fed through the metal line.
The 6mm screw is to adjust preload on the wastegate spring.
Sent from my CPH1937 using Tapatalk
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Thanks
I was thinking it was a k24 from the description above. Plan on taking it for a drive this afternoon.
Have increased the preload a mm.
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Finally was able to do a test to see if the boost changed, with one turn in on the wastegate control, It went up a pound. The car felt like it came up faster.
I was getting a boost starting at 25mph in 3rd and 30mph in 4.
Since "normal" is 9.4-10.3 and I am getting 9psi now and can really feel it come on, I think I will leave it alone for now.
My run consisted of picking up 600 pounds of animal food. Wasn't nearly as peppy on the way back.
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Glad you got some results from all your efforts.
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Had a road trip and really like the way the car runs. It is so much quieter, At low speed, I can run 1 gear higher than it did before the last fueling change. Even though I can't see how the max boot setting would be a factor, at low speed there is only a couple of pounds that start at lower rpm.
Ran it to about 85 for 20 miles No overheating or other weirdness.
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Nice.
What kind of boost were you getting at 85?
Got an EGT gauge?
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I think around 6-7 but honestly don't remember looking at it too much ,maybe at 2/3rds the way to the floor. I think one time when accelerating I had the pump to the floor. for a few seconds. Going down the road at 70 it has about 3-4 with steady fuel.
No EGT, one of the reasons I don't want to change boost or fuel too much. The mixture control still has safety wire on it. I did rotate the diaphragm on the boost enrichening 180° moving the fueling cone from lean but didn't rotate the star wheel under it. I am not aware of smoke when accelerating.
Most of my driving is under 40 on rally style lightly traveled roads, Most of the time I don't see other traffic, occasionally there is other traffic, kids, horses, a good place to get the motor up to temp before turning onto 2 lane blacktop roads. The biggest change in driving is surprisingly at low speed part throttle going up hills. It is easier to feel seat of the pants. Seems odd as most of the changes that I have made seem to on the higher end. I do feel boost a lot lower.
Overall happy with it. I imagine the economy has been affected some. Cant have power without fuel.