Advice on where I stand with my car after it lasted less than a week after mapping.

A little advice from K Series Turbo Owners please.







Hi guys, generally just after some advice really.



I'll start at the beginning.

So as some of you may know, I have a BRM. I decided to go the route of VVC turbo, as in my mind with the Emead my rald controlling it, it should all be hunky dory and would be an interesting experiment.

I had a new bottom end, gasket and head inc new belts, tensioner and water pump fitted to the engine whilst it was out on an engine stand.

All this work was done by me, and I made sure I was extremely meticulous about my build.

The engine was fitted and ran okish, a little lumpy but obviously needed a little mapping.



I took the car to Emerald in October, it was fitted with a Malpassi FPR there and was adjusted by John.



The mapping started and I was obviously ****ting my pants. All seemed to go quite well and it made 202bhp with 200 lbft of torque, not bad.

I decided to drive home in the lowest possible map setting as to get used to the extra power.



I drove the car for about five days like this then decided to try the high boost map. What a difference! A proper shove in the seat!!

As i took my mate out in it driving home to my parents to retire it for a short while, I noticed that the analogue boost gauge was showing 14psi plus when booting it. I though it was my fairly cheap boost gauge overreading somewhat as it had only been mapped at 9.7psi the week before.



I asked my mate to have a look and confirm to me it definitively showed this as it was hard to drive and see at the same time, he confirmed this just as I got a sudden loss of power, and white smoke out of the exhaust. I coasted to a stop and noticed coolant dripping from the bottom of the turbo, the AA arrived and immediately suggested HGF.



Got towed home to take the head off, head comes off and crack on liner 4.

At this point, and it has taken a lot of time and money I set about rebuilding the bottom end.



New gaskets, oil, coolant and a new turbo later (I believed the water seals had blown when the cracked liner pressurised the coolant) It was running again.

Whilst I was at home thinking about things I began to wonder if my boost levels were actually that high.



So I plugged the laptop in with my mate in the passenger seat and began testing the maps.



Low boost map – 7.68 peak

High Boost Map – 13.05 peak (I let off the gas at this point as I was worried it was going to crack another liner.)



So with my findings I emailed Emerald,



Hi Leoni,

You may remember me, I had the Rover BRM with a K series turbo conversion.

It was mapped with you some time ago, however after driving it less than a

week, I managed to crack a cylinder liner.

My analogue boost gauge was showing 14psi. It was only supposed to be

mapped to a maximum of 9.7psi. I assumed this was my gauge not being

calibrated properly, there was also supposed to be a feature enabled, that,

if the boost pressure conditions ever met 12psi, then the ECU would cut the

ignition as to prevent damage to the engine.

I have now re-built the engine, replaced the turbo as when the liner

cracked it pressurised the coolant system, which in turn blew the seals on

the turbo.

Obviously this has been a very time consuming and expensive exercise.

Unfortunately, I have been unable to test what boost my car was running

until I had the engine rebuild and everything replaced.

Today, I took the car for a short drive whilst having my laptop connected

and the data logger running. I have discovered that even in the low boost

map, the ECU is seeing much higher boost values than expected. The high

boost map has shown a value of 13.05psi, which is way too high for a

standard K series engine, the value is supposed to be 9.7psi. This

also goes above the safety setting in as described above.

Therefore, I believe that my map is at fault, and I also believe that the

cause of my liner & turbo failure is due to this. Needless to say that

I am quite

concerned about running my newly built engine in this state.

I look forward to finding a way we can resolve this matter.

I have attached two excel documents from my data logging session on a short

drive.

As you will see the low boost map is supposed to be 4.7psi Max and shows a

peak of 7.68psi.

Regards,

Gareth



I then waited a week with no response so rang them and got this reply.



Hi Gareth,

Boost alone is not going to crack a liner. A cracked liner can happen on normally aspirated engines - usually the result of a build problem or ingesting water from a head-gasket failure.

The boost control can operate in different modes. Normally it is used to lift the boost a set amount above the base boost pressure which is mechanically determined by the wastegate. If the turbo/wastegate or associated plumbing has been changed/disturbed then it is quite possible for the boost to now be higher than it was originally.

If you disconnect the boost control valve the engine should only run at the boost pressure set by the waste gate. This should be approximately 4-5psi. If the boost is higher than 5psi then check that the pipes between the inlet manifold-boost control valve-waste gate actuator are correctly connected.

The ECUs over-boost cut function has a time limit setting as well, i.e. it will only cut the engine if boost is above a set threshold for a certain time.

I assume that John did the mapping in this case. I don't know the situation with the boost limit, i.e. what it was set to or if it was enabled or not.

Best regards

Karl

Emerald office



My response,



Hi Karl,

On a K series 1.8 engine where the liners were made thinner I would beg to differ. A safe maximum is around 12psi for the liners, Boost can have a direct impact on cylinder liners, hence why when people tune their K series turbos, myself included on my current forged build have gone for ductile liners.

The engine that I brought to you had had it's head gasket renewed a month earlier, and once the car was running, I did a compression test which tested perfect, to determine why it was running soo rough. It wasn't until I spoke to John on the phone that we discovered that it was overfueling causing the rough running.

I do agree that since I have changed the turbo, that the wastegate could be set slightly differently, so tomorrow I will swap the old unit from the old turbo which is still in the car. Disconnecting the boost controller has produced a figure of 5psi.

John did do the mapping, however I cannot find anywhere on the ECU where the thresholds for over boost are set.

I look forward to hearing your thoughts, also if you could look at my individual map and confirm that the over boost feature is/not enabled I would appreciate it.

Regards, Gareth.



Again their reply,



Hi Gareth,

Ok, I understand the concern. My point was that very high boost, detonation or water ingestion is the usual liner killer rather than a momentary over-boost.

The open-loop boost control works by bleeding a proportion of the boost away from the actuator in order to elevate the set control point – the resulting boost can also be affected by other factors, e.g. turbo condition, exhaust back pressure, etc. Boost level is normally discussed before it is set – we like to err on the side of caution, usually 10psi max and ~190-200bhp for the Rover K turbo.



As both your low and high boost curves are higher than originally set then it does suggest the control pressure is offset by something – a change of turbo/actuator could be the cause.

I would leave the boost control valve unplugged for the moment. The boost table will need to be done again really to reset the boost back to where it needs to be on the low/high boost maps.

I have just looked at the copy of the map stored on the rolling road PC and also looked up your power curves. All these do show the boost to be as you said they should be, i.e. 9.7psi max is shown on the high boost power run.

The maps show that you should have x3 boost levels. Map3 has boost control completely off (boost purely determined by the wastegate). Map2 is set for 7psi and Map1 is the high boost version. The over-boost limit is enabled on map1 (high boost). The boost limit is set for 13psi and >3.0 seconds, i.e. the engine power is cut if the boost exceeds 13psi for more than 3 seconds.

From what you describe and looking at the map setting it looks like any over boost conditions did not exceed the 3 second timeout to trigger the protection.

John will be here tomorrow so it is probably simplest if you talk it over with him directly.

Best regards,

Karl

---------------------------------------------------------------------------------------------

So at this point I spoke to John yesterday, we checked everything and we confirmed that the wastegate only was producing the right amount on my boost gauge 5-6psi. therefore the actuator was in roughly the right place.

We also adjusted the safety feature for over boost, where it was previously set at if boost is over 13psi for more than three seconds. (In my mind the ecu would let it boost to any figure for more than 3 seconds before doing anything i.e 20psi) We changed it to anything over 11.46 for 0.3 seconds.)

We then decided to take some boost away on the controller, taking 10% off from 2k rpm onwards, I did another test and it came back overboosting still, took another 5% off still hit 12.32psi. so with 15% off in boost control I still managed to hit 12.32psi then I almost went through the windscreen as the engine cut out for a split second, it certainly never did that before!



So as you can see, they're not willing to take any responsibilty, and I'm massively out of pocket, what do you guys think?



Here are the logs:

http://ift.tt/1GPcBte



http://ift.tt/1GPcBtj



www.dropbox.com .. %20boost%2012-03-2015.xls?dl=0



www.dropbox.com .. %20boost%2012-03-2015.xls?dl=0

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