ipp pressures

[zx_volcane]

Anyone happen to know the stock ipp pressures from bosch?

VW boys have some numbers, but from my research they're different for each pump number, so maybe not so useful for 1.9 pug pumps.

Also as far as I can tell, when set up on the bench, they're set to a stock pressure from the book, rather than tuned to give x amount of advance at x rpm.

So shims are set in factory to give that response at book ipp pressure.



Thoughts? Or do I need to get friendly with a diesel specialist shop to get the info?

[Dan!]

Hmm tricky one. I can't imagine anybody with a stock Bosch would have ever bothered fitting an IPP gauge, but you never know. I'll see if I can dig anything out at work tomorrow for you.

[zx_volcane]

Cheers Dan

Case of not knowing what I'm looking for - with a rebuild I would have thought a pump would be supplying the right ipp, especially if its the valve that regulates it and has been left stock.

Would also be nice to know if the pressure vs rpm is supposed to be linear or if there is a curve to it - and then maybe I can see if I'm supplying enough pressure/fuel/advance up through the higher rpm range.

Or has anyone used a timing gun with an injector pulse adaptor to have a look at the timing response with rpm on one of these? Read varying reports on how accurate they are due to pulse traveling at speed of sound yadda yadda yadda - and they're not cheap to buy just to have a play.

[Harky]

Could be some interesting things appear on this thread...

But for now the figures I have been told are 43.5 at 1k, and mid 60 at 2k, thanks to anto for that.

I literally just got a gauge last week, have it in but just need to get it connected up!

[CJ_Derv]

Im glad youve got this thread saves me asking again lol

[zx_volcane]

Thanks Harky / Anto

So on those figures, its a none linear curve...

I'm interested to see if my pump is fuelling enough up in the 5k territory - especially running on b100 biodiesel which is thicker.

[CJ_Derv]

Il be fitting my guage when i find the one i want not sure which to get got the fittings just need a guage now

il speak with diesel specialist today and find out if he got anything on paper to go off as im up there picking more bits up today

[zx_volcane]

I went for a cheapish 50mm back feed gauge, so it can be mounted fairly oem - any hydraulic place should do them - or ebay.

Cheapest gauge to buy out the lot anyway

Mine reads upto 300psi, which has got to be overkill - 200 should do it. Only downside is they're not backlit for night viewing.

[Harky]

Yea mines the same, ebay job, mine only goes to 200psi though, should be more than enough from what I've read elsewhere.

Not sure if the graph is linear or not, I've seen graphs of various pumps but can't honestly remember them that well, hopefully CJ_derv will come up with something more solid!

[zx_volcane]

Would have thought the curve of the graph will tie in with the response of the timing spring - and the necessary advance required as the rpm increases.

Wherever this is linear or not I don't know, but thinking it prob isn't as simple as that.

Hopefully if we have enough points lower down we can make a good guess as it goes off into the unknown and out of spec high rpm territories.

[darrenjlobb]

The timing piston position dosnt relate directly to the IPP, throttle position / rpms/max fuel position all effect the timing piston, as the IPP is just one side of the force, fighting against it is the plunger rotating, which force is effected by all of the above things....if that makes sence...

[zx_volcane]

So it moves depending on the difference between the two pressures on either side? Not just spring one side, ipp the other?

[darrenjlobb]

Well it moves ipp vs spring+roller load.....roller load increases with injection load basically...if you try to imagine the more fuel its putting in,the harder the plunger is to rotate as its pushing on the camplate, meaning more ipp is needed to overcome it.

[Ruan]

Not totally read the thread, not sure if it's been mentioned, but remember that there's two types of advance mechanism in the VE pumps, the ones with the solenoid on the front aren't just for cold start... They are load dependant advance mechanisms.... When you mash your foot in one with a solenoid on the front, the IPP will jump up, on the capped off ones, it'll stay static...

There was a thing for a time that people rekoned that the capped off pumps tended to make a bit more power, due to the fact that they could have a bit more total advance...

[darrenjlobb]

As Ruan said, there are differences in pump design, I call the ones with solenoids "cruise pumps" they basically have an extra fuel way that bleeds fuel pressure from the pump body when the gov is in the extended position, meaning that when your doing 5krpm cruising with no load, there isnt the same ammount of advance as there would be under load, or with a pump without the system, just keeps engine noise down / technically helps mpg...

[Ruan]

Exactly, when you take your foot off the accelerator slightly, you hear the timing come off, when you mash your foot down you hear the advance jump in... When I had the IPP gauge on my car, the pump pressure would instantly jump as soon as you bashed the accelerator to give it more advance. Makes for a much nicer normal drive if you run quite a bit of timing as it's only there under load.

[zx_volcane]

Interesting.

Pump I've just destroyed had the solenoid, pump I've replaced it with just has a cap. Thought there was a difference in how the ipp was responding to throttle, but put it down to one being knackered.

Well it moves ipp vs spring+roller load.....roller load increases with injection load basically...if you try to imagine the more fuel its putting in,the harder the plunger is to rotate as its pushing on the camplate, meaning more ipp is needed to overcome it.

Makes sense, but still presume spring/shims are set up with this in mind and give correct advance under load?

Think what I'm trying to get at is this, you do a gov mod so you can fuel up at higher revs, then you extend the range of dynamic advance to take advantage of it, now I'm wondering if I need a higher ipp to trigger that advance at higher rpm or wherever stock set up will just continue to work beyond what it was originally set up for.

Bumping the ipp in my eyes is likely to just shift the starting point of where the advance piston begins and ultimately result in less range - or if its not a linear response, then it alters the curve and maybe you get more advance in quicker.

[darrenjlobb]

To put it simply, grinding the piston /shimming the cap wont give you any more timing unless you work other things at the same time....infact, if you open the pump up enough, you wont even be getting the full stock travel of the advance piston let alone more....

[zx_volcane]

I think I see what you're saying, I'll make a couple of adjustments and see what happens...

[JamesPT]

Sorry to Revive old thread, but better to Search and Receive than to have never Searched at all!

I've got a simple question to the Bosch VE Guru's:

After swapping my Lucas to a Bosch VE, the VE has the side solenoid, but its unconnected. Should I wire it up to a WOT switch?

To Activate (12v applied) at WOT or 90%-Wot?
Or to be Activated from 0 to 90% and grounded 90-100%

Is the different worth it? (the actual wiring is easy as everything is already there).
Am I losing power &or efficiency?

[zx_volcane]

solenoid on the side of the pump is just for cold start advance - little to be had by connecting it up to a switch / wot ..etc - when it is connected up properly it'll turn off when temp hits 65c

only adds advance low/mid end iirc and not linerally throughout the rev range

[Dave]

This thread makes me horny. Cant wait to fiddle with a VE when I get back to UK baha

[darrenjlobb]

This thread makes me horny. Cant wait to fiddle with a VE when I get back to UK baha

hehe

[JamesPT]

Ok, so basicly since I live in a Warm Country, its not needed.... Its not really that warm today only 16'c... Had to put on a jacket!!!!!!!!!

[nominous]

Only downside is they're not backlit for night viewing.

On a similar gauge I use for fuel line pressure monitoring, I drilled a 5mm hole in the back near the feed and added an LED. It's bright enough to see the gauge at night as the light leaks around the sides of the face.

[Dave]

This thread makes me horny. Cant wait to fiddle with a VE when I get back to UK baha

hehe

Darren is it really bad that the first thing I noticed in your RR pics was the injection pump test bench in the background haha

[nominous]

43.5 at 1k

Was that number correct ?
IT seems higher than what the VW boys have but granted every pump is different.
Did anyone with a gauge measure the stock IPP ?
Or happen to have esitronic and read it out from that...

[zx_volcane]

43.5 at 1k

Was that number correct ?
IT seems higher than what the VW boys have but granted every pump is different.
Did anyone with a gauge measure the stock IPP ?
Or happen to have esitronic and read it out from that...

Esitronic would be useful I've had a look for it but never come across the right disk with the info in, might be worth phoning up a diesel shop and asking them outright for the number - but iirc its around that

When checking sources need to find out if they are quoting pump speed or engine speed, as there is a x2 difference

[Dave]

Mine was around 45psi idle, but would see 170+ at 5k+ rpm which is less than is required for fueling up there really but I never modified the IPP reg much.

[Ruan]

Increasing the IPP regulator tends to only cause one thing - chronic advance knocking at about 1200rpm until the turbo comes on song.

Then at 5000rpm it's still down on pressure anyway.