Hope you get it sorted and its an easy fix.

:sad::sad::sad:

Right another update i guess is needed...

It is still loosing coolant from the expansion cap when making use of 'some' of the extra torque, so i am pretty sure that the gasket has been compromised, so a strip down will be needed in the near future.

We have got a few ideas from some threads on .org as to what is the root cause, as it shouldnot be the fuelling directly causing the problem (butit might be we dont know)

So back to the update...

The thinking is that the exhaust housing for the GT15 family is far too small for what we are asking from it, and as such, the EMP (exhuast manifold pressure) is rocketting.... with the pressure high in the exhuast manifold it is doing enough to blow\compromise the gasket with the high boost from the inlet side.

So we are going to try and either tap the EM or use the EGR blanked plate and fit a pressure sensor, and just see what is what.

If the EMP is the root cause then there are a couple of options...

Either fit a custom external wastegate, with some pipework and a bit of a flex to join up with the decat - as this would basically show that the internal wastege on the GT1549 we have is not big enough to cope with dumping all the excess exhuast gases so we would be able to bypass the turbo completely and dump the excess pressure that way.

The turbo can still be controlled with the boost readings from the MAP as normal... although i am still thinking of getting a 3bar sensor fitted rather than the 2bar currently in use...

Or i will be going down a larger VNT turbo with electronic boost control, with a adaptor plate for the Exhaust manifold and a custom downpipe.

the later option is last resort, as i dont really want to detune the car (as it stands we think SDI's and remap is the most the turbo housing can take - so peak 250lbs ft and max 150bhp (or around 200lbsft at 4000 rpm), but i also dont really want to have the cost and the hassle of buying a new turbo and trying to sell the hybrid.

If we get the results as expected then i dont think that any-one will want to pay a decent price for a 'pointless' turbo either so it is a bit of a damage limitation excercise now! :(

So all is not lost, but it seems like it is still a way away from completion....

Any-one know where i can get my hands on a pressure sensor that can cope with up to 1000C, as all the ones i have found stop working after 250c :laugh:

Right we have worked out a way to measure the EMP.. just going to use a new blanking plate with a boost guage plumbed into that.... a bit of brake line or something similar to disipate any latent heat then on to normal boost hosing to run it to the cabin... or just something a bit closer if Matt is able to get some testing done on a RR...

Still looking at the various options for once we get the EMP readings - I think i would have to rethink my pipework if i go with the bypass system, as i am almost 100% there is not enough space to join it up with the decat, so the downpipe itself will need to be modified....

external wategate system looks like it would be in the region of £250 for the bits to control and operate that, plus the labour to get it fitted... then the extra cost of getting the pipework plumbed in properly rather than just using a 'screamer pipe' for testing purposes

My concerns with this route is that it is going to be quite hard to control the external wastegate, - As you should see pressure spikes under normal conditions - eg tootling along then stamp the loud pedal when in a rev range that allows max turbo boost) and stopping it opening too early and dumping the boost from the tubo's internal wastegate

If i effect the lag of the system i may as well jsut get a bigger turbo maybe something from the GT20 family...

Still doing plenty of research to try and work out my options.... I will avoid detuning the car if it is the last thing i do :D

Good to see you are keeping at it, all too easy to throw in the towel.

Right quick update..

I have come to the conclusion there is almost nothing out there that will give me the daily drivability i am after without needing a lot of extra work to get it to fit...

As VNT is not an option (yet) i have decided on the pressure release system.

However after speaking to Grant (GBE) he has given me a few pointers to try and get this to work correctly...

Firstly he expects to see EMP spiking well above the boost pressure, so as i am running 25-26PSI on the intake side i can expect to see spikes of around 35-45PSI...

Due to this, there will never be any form of boost controller that i will find that will work - as they are all designed to keep boost steady at high rpm not dump pressure at high rpm...

So what we are going to go for a decent external wastegate with a restrictor plate bolted on the exhaust manifold (at the EGR point) - the dimentions of this are going to be a bit trial and error though - so a high temp valve may well be the best bet...

then the same thing on the other side of the wastegate - if the spring on the wastegate is high enough to resist the main spike and the pipework doesn't allow much flow through it. we should be able to dump the excess backpressure.

So the good news is that costs are looking at the £60 for a decent 38mm wastegate and then some pipeing\adaptor plates to be made up...

Other possibly good news is that rally_matt might be able to get his hands on soemthing decent to record the EMP's directly...

If and when the trial and error is all worked out, i will then plumb it into the downpipe so it passes MOT's :)

reading around some of the TDiclub posts (big VAG tuner forum) i might even see a nice jump in bhp if the balance is got right :D

Best of luck Pete, keep fingers crossed for you.

:yes::yes::yes::yes:

Sounds fairly positive then pete all a learning curve for everyone involved :)

All sounds rather interesting, makes a change from the normal reading.

In effect we are just running a 'low blow' turbo setup on a car that has high boost pressure.

The challenge we are going to have is to get the restriction small enough that it doesn't dump too much exhuast away from the turbo - but not so small that it is still going to over pressure the EM.

Would be possible to do the same thing with a larger external wastegate - as the problem we have is that the internal one is not big enough to divert enough gas away from the turbine housing....
That however would require a fair amount of pipe re-working so this is the easisest compromise...

just have to get the bits together and then see how it all pans out... (it could still fail but if it stops HGF then in one respect it will be a success...)

Right car is booked in for another 'Holiday' with Matt next friday.

Going to hook up a boost guage to the Exhaust manifold (where the EGR is blanked) to get some figures as to what it reached achieved when it spits the coolant out.

Also going to try to get something into the coolant system to read the pressure in there to make sure we are getting HGF and not just a general cooling system problem.

Going to check the thermostat just to be sure it is working properly, and also the waterpump.

Pending what is found (but we both expect it to be HGF), the head will come off again and stripped down and rebuilt, then the bypass system will be fashioned.

If we can limit the EMP to be the same as boost then we should be laughing... so around 26PSI

no idea how long this will take, so i am going to be in the little 25 again for a while i think...

still toying with uprating the MAP sensor to a 3bar one so i can get proper boost from the scangauge, but i suspect i will need to get the ECU tweaked a little so just going to get a cheap boost guage to make sure everything is right and maybe get round to that later on.

Be interesting to see what is happening, hope its sorted and not too many ££££'s.

:thumbsup::thumbsup::thumbsup:

Some good news - Car might not have HGF at all - been doing soem double checking and my bottom rad hose doesn't get hot.

Suggests either faulty thermostat or waterpump not up to the job - bits broken or not ale to flow enough when under full throttle.

Going to get that investigated first before we do any 'difficult' stuff.

Also getting my mid section replaced with a nice shiney 2.5" stainless wingy section, to complete my whole exhaust.

Also needs to have the rear right caliper checking as i think it is not sliding quite as it should and is binding a bit.

might be a nice quick and easy fix.... or it might still be a PITA :laugh:

Let's hope it is the former, about time you had the rub of the green.

Whoop whoop got some good news this morning - Matt was doing a few road tests with my scanaguage and noticed that it was running a bit hot, and then all of a sudden the temp would drop back down. EG from 96+C down to 88C -the usual up to temperature reading...

and took the termostat out, put in a pan and thermostat is not function as it should. New OE rover one due to be fitted tomorrow when it is collected along with a new waterpump (just on the safe side replacement)

Keeping fingers crossed and tring not to jinx things but the car might for once not have worse case scenario situation :)

Going to then get a reading for the exhaust manifold pressure if the car holds coolant once more at full throttle high rpms and if it is within sensible levels EG +- a few PSI of boost then all is well and i can drive it how it ought to be driven again :)

Sounds hopeful pete :)

Keeping everything crossed for you, sounds good though.

:smile2::smile2::smile2::smile2:

we will also see if it dont fix it whether a kv6 cap holds the coolant in, as it is rated higher than all the other caps....

not so good news i am afraid - looks 99.99999% sure i have got repeat HGF.

got the car for a few weeks as Matt needed his back for a while... going to have to seriously consider my options now :(

Bummer, hope you can sort it out, and its not too costly for you.

:(:(:(

Well I have given the car to Matt for open heart surgery.

I most def have repeat HGF as there are now sooty deposits in the coolant and it is drinking water at a very alarming rate :(

So we are going to look at the wire & groove option again depending on what turns up when matt opens it up... it will be the best option to avoid it happening i am sure, but last time the guy advised Matt it could be a bit marginal for the head...

I am considering then to get the block done instead, but obviously that will be an engine out job...

When it is all bolted back together matt will get a reading of the Exhaust manifold pressure, and we can see if it is too high and work on getting it lowered if it needs it.

Oh and the car needs the ac looking at (maybe re-gas) and an MOT while it is there.

It was funny, my GF was following me today (as i am going to be out the country with work for a few weeks, matt has not given me his little R25) and even with only using 50% throttle and short changing at 3K rpm, her 206 could not keep up and i got an earful when i arrived at Matt's workshop.

Even a poorly, tuned L-series is a quicker than a 1.4 206 :D

Pete, 3k is nearly flat out for a derv, no wonder you got an earful!!:whistle::whistle:

Hope its a cheap fix, all the best.:):):)

not in mine it isnt Peter! mine pulls all the way to 4400 ;) (well it did for a short while until it blew itself up :laugh:)

dont think it is going to be a cheap fix, taking the head off requires all the belts etc off as well, and if i get the block wire and grooved then that is engine out completely....

Ah well it is keeping me out of trouble...

Edit oh, a nice satanic post count i have now :laugh:

Hope its not an Omen!!!!! :whistle::whistle::whistle:

:):):):)

Right quick update...

Head came off on tuesday and Matt gave me a call on wendnesday - repeat head lift but this time coolant at 1 & 4 went. around the fasteners for the ARP studs it has stayed nice and tight but lifted in the middle :(

not really sure where that leaves us, as it is looking like it is a design issue rather than soemthing we can fix....

but am still hoping some analysis of the exhaust manifold pressure gives us a final avenue to look into... but might just have to tone it down *sniff*

hmm has it really been a month.... where did it go i wonder... ah yes i remember, out the country...

Anyhoo spoke to Matt and the car has been rebuilt and he is putting on a few running in miles.

needed to have a new set of dowels as there was too much play with old ones, and a new set of lifters. the old ones had signs of impact damage; Matt can only surmise that due to the higher temps and pressures, the metal of the cams expanded and caused contact.

The good news is that the car is running better than it has been for a while and is just waiting on a 2 new tyres before it goes for an MOT (sat or monday).

Matt was just off to the shops to buy a boost gauge as well to fashion up the exhuast manifold pressure reader, and then we can see quite what the EMP is hitting on high boost high RPM situations....

Get the Aircon hopefully sorted as well...

However i was slightly concerned when Matt started talking about custom exhuast manifolds and 16v heads again; I think he shocked himself about being so interested in an 'an old tractor engine'. However it is not a route i plan to go down anytime soon!

More likely would be a VNT turbo if anything :laugh:

Hope its sorted, the other mods sound like serious money!!!

:yes::yes::yes::yes:

Glad to hear its back up and running, dont really understand all the technical stuff involved on the darkside! Although it sounds expensive:unsure:

Got my fingers crossed it all goes without any problems :)

EMP! I'm staying well away from you then!

lol Dont want to start glowing green or go up in a puff of smoke!! Quite fitting for a Derv I guess

heheh different EMP; this one is exhaust manifold pressure....

tho that would be a good way to make sure you win a drag race, just knock out the elctrics of the competitor....

I am making a guess here Jay, but i think that the rebuild with all the new bits and gubbins will prob have been more than your new engine was :(

Bloody hell good job your not a student too! :laugh:
Reckon you could top this list pretty easy!! http://www.themgzs.co.uk/vb/showthread.php?t=13093

hehe yes i think that you are right there..... i have avoided doing all the sums for a while, it scared me last time i did it about 2 years ago lol (that was before the 1st HGF :laugh:)

suppose it is one advantage of only payring rent atm, and having a job where i am sent lots of places so i have very little living expenses.... tho the home front is about to change soon...

Initial testing suggests that we do have high exhuast manifold pressure, but the gauge/reader needs a minor tweak as we need more cooling pipework before the switch to plastic for the boost gauge.

so looks like a method to bleed off some pressure is the way to go.... hopefully more info/results next week.

How did the Seat Derv's in the BTCC get over EMP, they used to go like stink and they are one of the reasons I got my derv.

Must admit I thought it was the BMW derv engine not the L series ( just shows how much I knew) Saying that I'm pleased with the way it goes.

Look forward to the next lot of results, hope its not too costly this time.

:wave::wave::wave:

probably by running a turbo with VNT.

it is basically a huge turbo (as denoted by the GT20 or GT22 starting numbers), but by changing the vane angle you get it to behave like a small one. so you get high resistance at low rpm with the vanes closed, and low restance at high rpm with the vanes open.

That means it spools as fast as our little GT 15 family units, but are big enough to flow enough exhaust gas and drive the compressor like a fixed vane GT 22 unit. it results in the ability for well over 200bhp - assuming that the fuel is there.

All modern diesel engines now use VNT units, they are the way forward, but they are more fragile than 'old style' fixed ones. which means this like fuelling and boost is much more important to get right early etc.

Controlling it on the L-series is not easy however, but there are a few people trying to do it as we speak. either has to be done via a seperate control module, or tie it into the EGR vavle controller - but for that you have to remove the EGR, so that would fail MOT on a Mk2 as that can't be disabled yet :(

We are getting there, and this last little bit will be cheaper than the rebuild was for sure :)

been a few days so figured i would pop an update up...

the pressure reading system is proving to be a bit of a PITA to fabricate, as it keeps melting the oil feed pipe Matt is using to connect the brake line he has attached to a plate in the exhaust manifold.

so even tho there is no gas movement as it is sealed it is still transfering a hell of a lot of heat along it.

I had hoped to pick the car up this week, but my schedule will not allow this now, so prob will be next week sometime (on my way back down from hull most probably)....

will probably now also just use a ball and spring based boost controller to dump any excess pressure rather than worry too much about external wastegates, as it looks like heat is going to be too much of a factor, and i am still concerned about dumping too much gas with summit like an external wastegate...

Cant you just turn the boost down, ( I dont know anything about boost etc, only that our whiz kid fitter, who used to have a big American muscle car and took it to Santa Pod, boosted mine up a bit)

If your turbo is pushing out 25 psi is it possible to cut it back a bit. Cant remember what he pushed mine up to, think it was 2 psi above whatever. Anymore and he said it caused the engine to knock.

Best of luck and hope its sorted.

:smile1::smile1::smile1::smile1:

Theoretically i could turn the boost down, but that defeats the object of having the hybrid turbo - that has been designed to cope with 28PSI on the intake side of things. (I am running it at around 25/26 PSI atm

the problem is that the internal wastegate is too small to bypass enough of the gas from the hot side, but controlling EMP via boost pressure (intake) is not actually a sensible way to sort the problem - it works by reducing the effective combustion of the fuel by removing air, but this method theoretically would be more effective, as it is dumping the excess pressure post combustion.

Eg if i reduce boost i have to reduce fueling as otherwise the fuel wont be fully combusted, i will get higher smoke, and see the EGT's rise again. At the moment they are nice 'low' 750C while under sustained full throttle - well within turbo temp tollerances and the manifold itself. (i had seem 850 with it still climbing before i backed off the throttle in the past - and that is way too hot!)

I am still quite surprised by the knock comment - diesels dont knock usually as there is no way for the fuel to ignite before the compression is at the max - and an excess of air just results in more complete combustion with a diesel. (out the factory they all run lean as it is hence no smoke and better emissons)

There is no point turning your turbo above 19PSI as the turbo itself becomes inefficient and can't take the strain of the 150K+ rpms that that sort of boost is asking of it. Seen a few pics on .org where the housing starts to crack after a while, and the bearing give up the ghost as they are too hot and dont have enough lubrication...

Car is 99% there now, just this last little niggle.....

Suspect he was just keeping it safe.

Glad your almost there with your one.

Santa Pod next??????

:clap::clap::clap::clap:

Right I have picked the car up and done a 100 miles in it to get me back home and get some readings for the EMP...

the news is both good and bad:
the bad news is that we have got high EMP, on full throttle in 3/4/5th it is above 2.5 bar - i guess 2.75 to 3.0 as it went off the end of the guage.

the Good news is that now we know this we are able to work out a solution, and if you dont use full throttle and gradually build the boost by rolling the accelerator the EMP keeps lower (but still higher than it should be)

so while we\I do some research and bandy some thoughts around on how to correct it, i wont be thrashing the car - so no Pod just yet Peter ;)

Maybe this needs a seperate thread, but any EMP possible solutions please send me a postcard with the thoughts and method to solve it.

Ideally we want something like an idle control vavle that opens up gradually as the pressure against it increases but closes off nice and slowly as pressure drops.

Other requirements
It has to cope with exhaust temps of around 800C
It has to cope with sooty exhaust gases
It can't dump too much gas from bypassing the turbo and stalling it

Ay thoughts let me know... i am a bit stumped, i have a few ideas but nothing that in my mind will be easy to implement without a large amount of time\effort\experimentation