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JX Boost pressure setting |
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boxer998 
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Joined: 06 Jul 12 Location: Wirral Status: Offline Points: 23 |
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 Topic: JX Boost pressure settingPosted: 13 Sep 18 at 16:16 |
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Hi
Not sure how old this thread is but it's deffo the most interesting one on tuning the JX I've seen. Would appreciate some help: I've got the 1.6 Td I'm running a GTD pump top on a stock JX body, with governor mod carried out. Defender intercooler with fan ( fan yet to be connected) fitted into the side of the engine bay by a very cool welder, oil cooler and at the moment just the boost gauge. I've not adjusted the fueling at all and I get quite a bit of smoke when I boot it but it clears to nothing on steady or progressive throttle. ( passed MOT) The pump has transformed the bus, I can't get any more than .6 bar on the gauge ( bleed valve fitted and closed. but it goes really well up to 78mph on the satnav I'm on 215/65R16s and the stock 5 speed box. so need to work out what that is in rpm. Bit too much smoke on the heavy foot but the boost won't come up any higher with one turn out on the bleed screw. Main thing I changed recently is to take the slack out of the throttle cable and adjust the stops it seems to rev much higher. I've got a Tdi if I blow it up but I really like the way it drives.
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dave friday
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Joined: 18 Oct 06 Location: Albox Spain Status: Offline Points: 459 |
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Posted: 25 Jun 16 at 10:02 |
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Yes it's the max temp (810 deg c) for short periods,it seems to stop getting any higher!!
This is foot to the floor up hill in top gear and into a strong wind. Tickover is about 106 deg c. I've seen pictures of an inter cooled van showing 700 deg c. I still have to fit my new fast acting "exposed tip" probe!! And replace the oil pump with the new one. Edited by dave friday - 25 Jun 16 at 10:33 |
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1992 1.6td syncro
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Zeb
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Joined: 12 Sep 08 Location: Portishead Status: Offline Points: 467 |
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Posted: 25 Jun 16 at 01:03 |
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If the temp reading is correct your engine will be melting surely. Maybe ok for very short bursts but 650-700'C for any length of time seems to be max recommended egt temp.
Edited by Zeb - 25 Jun 16 at 01:04 |
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1990 Westfalia California 1.6TD
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dave friday
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Joined: 18 Oct 06 Location: Albox Spain Status: Offline Points: 459 |
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Posted: 25 Jun 16 at 00:13 |
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Thanks Zeb,I'm going to fit an intercooler before upping the fuel (800deg c!)
A boost controller could be used to make adjustments from the cab. Kr,Baz. |
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1992 1.6td syncro
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Zeb
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Posted: 23 Jun 16 at 09:48 |
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Bit of an update having picked up a worn pump for a couple of beer tokens from a kind chap called "uncle monty" on club80-90. The fuel delivery on and off boost is limited by the lda mechanism. The retracted stop sets the fuel rate off boost within the overall limit set by the max fuel screw. How to set this retracted lever position to match the fuel required just before boost kicks in accurately I assume would need a rolling Road or as I have done 20 Road trips until it feels like it picks up quickly without smoke. I would recommend leaving this alone if it has not already been moved. The upper limit is the far more interesting setting to play with. I first adjusted the rod length to the maximum lever arm possible that allows the retracted position to just rest on the stop. Then with a tiny blob of blutack on the max stop check your lda is getting to the max position. When confirmed you can allow more fuel on max boost by removing some material from the lda stop plate/lever or the stop itself as long as you have sufficient stroke left in the lda to get there. As I had a spare pump I took the lever from this and removed just over 2mm from it. Put a little blu-tack on the stop again and took it for a drive. There was a marked difference at top speed, it pulls away from 70mph (just under 4000rpm, 0.9bar boost) to 75-77mph much quicker. I cannot tell you if you need an intercooler to burn this extra fuel. I have one fitted and cannot see any smoke at all in car headlights at night unless the engine is cold and I put the pedal on the floor. One downside is my gets have gone from 550 degrees max to 575 degrees uphill doing 70mph. So with no intercooler watch the Temps if you do this. My healthy e46 2ltr BM and mk4 2ltr golf produce more smoke when pushed. I could probably remove a little more to allow a bit more fuel on max boost but I don't see the point; at this rpm I have no desire to get a better response as the egt temp will rise again as a penalty. If your engine smokes only on Max boost you may need to back the lda off a bit or get more air into the engine somehow. I also have a new k and n filter but don't know if this makes any difference or not.
Under normal driving the turbo boost picks up at just under 3000rpm getting you to 4100rpm plenty quick enough. If I labour the engine the boost will pick up around 2000rpm, this means it is easier to drive if you are lazy with the gears. I did the governor mod on the old pump which is actually simple to do on a bench but means you mess up your idle and max fuel settings to remove and replace the pump top. Due to this I am saving it for another day when I am used to the new power I have already gained. One thing I still don't understand is why anyone would want to fit a bleed valve kit if your turbo can get to 1bar or more through adjusting the wastegate. Mine is still fitted but closed. Cheers for now Zeb
Edited by Zeb - 23 Jun 16 at 13:38 |
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1990 Westfalia California 1.6TD
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Zeb
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Posted: 13 Jun 16 at 15:11 |
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let's hope I can see the details of the pump parts more clearly!
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1990 Westfalia California 1.6TD
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dave friday
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Posted: 13 Jun 16 at 11:59 |
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Tiled outside bar top!
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1992 1.6td syncro
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Zeb
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Posted: 13 Jun 16 at 10:29 |
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I thought about asking who the cat was! Also looks like your stripping that pump on the lounge carpet..
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1990 Westfalia California 1.6TD
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dave friday
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Joined: 18 Oct 06 Location: Albox Spain Status: Offline Points: 459 |
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Posted: 13 Jun 16 at 09:34 |
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The cats called Sausage and that's my mum in the 1933 Austin 7 with me driving.
I got a vacuum of .1 bar at 1600 rpm! So your right. |
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1992 1.6td syncro
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Zeb
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Posted: 13 Jun 16 at 08:29 |
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Thanks Dave. At least it's easy to now tell the max fuel position of the pin and cam so I can check that. I have found a worn pump on club 80-90 a kind chap called Monty is willing to give away for tinkering purposes. Just need to pick it up from Chard which is an hour away from me.
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1990 Westfalia California 1.6TD
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dave friday
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Joined: 18 Oct 06 Location: Albox Spain Status: Offline Points: 459 |
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Posted: 12 Jun 16 at 22:45 |
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1992 1.6td syncro
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doc.g60
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Posted: 11 Jun 16 at 09:37 |
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In fact this makes more sense when you look at how the spaceship LDA works. They have a vertically operating shaft with a cone on the end which performs the same operation as our LDA shaft, moving a pin in and out horizontally. There are replacement pins being fabricated for these which have a more aggressive angle on the cone and change the operation, if you google Bosch VE pump tuning you can find discussion about it.
The shaft on JX pumps has 180 degrees of rotation between max and min, but the cam plate only rotates about 45 degrees, with very little adjustment on the wee max screw on the pump lid.
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doc.g60
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Posted: 11 Jun 16 at 08:52 |
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You know what, I think I've got this backwards, I'll need to amend my previous post. Seems the pin retracts as the LDA operates. It must restrict the movement of the governor lever. Some more thinking required. |
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Zeb
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Posted: 10 Jun 16 at 16:34 |
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Great doc thanks. From that I understand what I need to for basic operation.
What I now need to understand is the lever movement relative to the shaft rotation angle. It would help to get a better look at the pin you snapped if you still have it? Looking at the pic you linked it may not be that sensitive compared to the top mounted space ship type?
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1990 Westfalia California 1.6TD
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doc.g60
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Posted: 10 Jun 16 at 13:53 |
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doc.g60
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Posted: 09 Jun 16 at 23:12 |
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I can't upload images to the forum yet but I've got some links.
This is the shaft that is controlled by the cam plate connected to the LDA The cam profile of this shaft moves a small pin which in turn pushes a lever back and forth on the underside of the lid. You can see this in the next photos looking at the underside of the pump lid. Here is the pin and lever with the LDA in resting position: LDA extended retracts the pin: This lever contacts the governor tension lever inside the pump the overall operation of which is too complicated to go into however the following image shows the things we are interested in. The fuel screw pivots the entire gov. tension lever assembly but the LDA pushes against the top of the gov. lever only. (A caveat - I've only gathered this info from reading on the internet / opening this pump after snapping the top threads off my LDA shaft and have no real practical experience of tampering with any of this on a running van. There is loads of info on tuning the pumps with the LDA on top and in these cases adjusting the LDA seems to be the easiest method of increasing fuelling, but I couldn't find any info on the operation of the JX LDA and pump lid so wanted to get some photos out there.) I'll let you get back to the real world testing now! (-Post edited to correct operation of pin.) Edited by doc.g60 - 11 Jun 16 at 09:01 |
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Zeb
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Posted: 09 Jun 16 at 21:06 |
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Hi doc, please do take some pictures just in case they help . As the pump is running well and there is no smoke under load visible to me I don't want to strip it down and create new problems.
Cheers
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1990 Westfalia California 1.6TD
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doc.g60
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Posted: 09 Jun 16 at 20:26 |
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This is a very interesting thread, I've been slowly trying to get my head round how this pump works. I have the same symptoms as Jon above since changing my lda seal, black smoke on load uphill or with foot flat but fine otherwise. It'll be great to see the results of all your tampering. Ive got a pump apart at the moment and will get some photos of how the lda cam / rod / lever operates in respect to the governor lever when I get a chance.
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dave friday
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Posted: 09 Jun 16 at 19:27 |
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What I did ( with the lda shaft off and the engine off ) was to move the throttle to max a few times,the cam moved a little ( just off the stop )
I'm In the same boat as you ,trying to find out how to set the pump up. |
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1992 1.6td syncro
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Zeb
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Joined: 12 Sep 08 Location: Portishead Status: Offline Points: 467 |
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Posted: 09 Jun 16 at 19:07 |
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Hi Dave, scratching my head again now then? When you said rev the engine you didn't mean rev the nuts off it did you? I actually removed the lda rod and connection plate, left the shaft and stop plate free to move, checked if moved freely by hand from stop to stop and then started the engine. Whilst moving the throttle lever by hand revved it a fair bit guessing 3000rpm max and no movement? I'll check again just in case I was having a "senior moment".....
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1990 Westfalia California 1.6TD
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