40 replies to this topic

[Anarchy]

Go to whoever is closest

[Winstar]

Lets just say we'll disagree, but we both know the number of boost related failures caused by pressure.

What the failure mode?

Pressure doesn't normally cause a turbo to fail, just a reduction in performance due to creep, if it's not design well.

[Thorney]

OK, you want this on an open forum then so be it. In the last month alone we've replaced three VXT turbos, all had been remapped by other firms. In the last 12 months we've replaced (on average) one VXT turbo per month. Some have been on completely standard cars and therefore covered under warranty but if the car has been remapped (regardless by whom) then the warranty does not cover you. The process goes like this, customer rings up complaining normally of oil smoke or an oil leak from the turbo area, books it into us as we're the UK experts and authorised by Vauxhall to deal with warranty work. Car is still under 3 years old so customer expects any problems to be covered by warranty. We inspect the turbo and see if the oil return and feed pipes are causing the leak and make any changes to those to see if that cures it, we road test the car again after its all done and if the turbo continues to smoke/leak then its normally knackered. Then we inspect the ECU to see if its mapped and typically we dyno it to see what boost it was running or on the road with a vacuum boost guage to confirm it. Anything more than 17psi of boost on a car with a full exhaust can cause premature turbo failure - fact. You're correct, the unit itself is rated to 23psi (overboost only) but if you combine the fact that the position of the turbo and the configuration of the exhaust with this (ie it gets bloody hot) the operational range of the turbo is reduced. This is also the reason why there are not as many corresponding failures on Astras, whilst the same unit is used in the Astra G it is situate at the front of the engine in direct airflow and as such is not subject to the same levels of heat soak and build up on the VXT. We run a maximum of 16psi of boost on stage 2 cars and we've never had a turbo failure that wasn't down to a manufacturer defect. We get 240-250bhp from a stage 2 and we don't need to run more boost so why take the risk? We only increase boost to higher levels on stage 4 cars where we use the Astra VXR turbo which has a higher rating and even then we only go to 19psi and we're still getting 270-280bhp, again without one failure. Even on my race car, which runs 330bhp we only run 20psi of boost (albeit on a different turbo). Winstar is right, boost doesn't kill turbos but heat does and increasing boost increases heat. Your post also explains why you need to run larger injectors on higher stage cars, you need the fuel to keep things cool as you're running (IMO) unsafe levels of boost, we don't need to use larger injectors as we get the power we want without the need to throw fuel into the chambers to stop them from overheating. Just in case anyone thinks this is scarmongering, outside my house right now is a VXT that has had £££ spent on it, IC's, clutch, larger injectors etc etc. It was remapped by another company (not Courtenay in their defence) and it melted a piston crown. Fortunately the owner bought it through a dealer and the dealer agreed to replace the engine (I assume the dealer paid because if it tried to claim under the Vauxhall warranty they would not only have it rejected but would run the risk of severe penalties from Vauxhall as it would in effect be fraud). Owner is understandably worried that the engine could have problems again so he doesn't want to risk his nice new engine so brings it to us. First thing we do is get it on the dyno and there's no doubt it produces the power, 270bhp but the tech2 logs show its on the brink of detonating all the time, on the road it starts to pink at higher rpm, thats running 22psi and its basically a hand grenade waiting to happen. Replacing a turbo will cost about £750-800, replacing an engine is in excess of £2500. If you can get 250bhp odd without the need to risk these then personally I think thats a better bet.

[MAP18W]

OK, you want this on an open forum then so be it.

Agreed....

In the last month alone we've replaced three VXT turbos, all had been remapped by other firms. In the last 12 months we've replaced (on average) one VXT turbo per month. Some have been on completely standard cars and therefore covered under warranty but if the car has been remapped (regardless by whom) then the warranty does not cover you.

Maybe you have, however I'm sure there are just as many standard cars getting units throughout the dealer Network. However 90%+ turbos that we have had inspected by turbo specialists such as Turbo Technics have failed not through increased boost pressure but lack of hot shut down procedure which is even more important on mapped cars which can run the turbo hotter.

Anything more than 17psi of boost on a car with a full exhaust can cause premature turbo failure - fact.

Anything more than standard boost will reduce the life expectancy of a turbo, but it's a balance. The problem is magnified particularly on software where the overboost threshold has been raised and no correction has been done to the fuel map thus the engine will run 0.85/0.86 lambda (i.e. excessively lean) through the mid range overboost increasing manifold temperatures which plays havoc with the wastegate seat.

We run a maximum of 16psi of boost on stage 2 cars and we've never had a turbo failure that wasn't down to a manufacturer defect. We get 240-250bhp from a stage 2 and we don't need to run more boost so why take the risk?

Unsure of the 240-250 bhp figure you state above as your website quotes "Approx +30 bhp (+40bhp midrange)" for the Stage 2 so 200 + 30 = 230 which is what your owners graphs typically show from your dyno and we have seen similar figures running 14 psi overboost rather than the quoted 16psi.

The "risk" as you say is not present when the fuel map is correct and EGT's are monitored during development.

Winstar is right, boost doesn't kill turbos but heat does and increasing boost increases heat. Your post also explains why you need to run larger injectors on higher stage cars, you need the fuel to keep things cool as you're running (IMO) unsafe levels of boost, we don't need to use larger injectors as we get the power we want without the need to throw fuel into the chambers to stop them from overheating.

No we didn't mention injectors in this post, but since you brought it up, all the TMS Stage 4 cars we've seen have run the standard injectors flat out through most of the rev range, thus running very lean, which raises turbo temperatures and means the car is running unnecessary retard which has a secondary effect of running the turbo hotter due to the burn occuring later (the later the burn the hotter the manifold). This is not scaremongering as this is something we have seen as have a number of stage 4 owners who have monitored their cars with the aid of a PDA etc. You will find our manifold temperature on 20+ psi on VXR injectors is significantly cooler than a Stage 4 on ZLET injectors due to the fact that there is no retard needed as the air fuel ratio can be run at manufacturer's level if required to maintain stable cylinder temps. We can get the power without the injectors but there is nothing left in reserve to fuel dump high temperatures (part of the motronic's inbuilt defence strategy when temps get high, not a Courtenay/Klasen quirk)

Just in case anyone thinks this is scarmongering, outside my house right now is a VXT that has had £££ spent on it, IC's, clutch, larger injectors etc etc. It was remapped by another company (not Courtenay in their defence) and it melted a piston crown.

Yes because we have never ever had an engine failure due to the extreme precautions we take, in ensuring our air fuel and manifold temps are within a safe operating range. A lot of our safety is bourne from the fact that in the UK our cars do not run to the extreme heat levels that Stephan sees and therefore he has to cater for, on the cars he maps that are held at V-max (a very hard test for any car) on German Autobahns for many kms. At this point you need additional fuel available to fuel dump to the same level as the manufacturer would allow to keep cylinder temps down at prolonged high load/rpm use.

Owner is understandably worried that the engine could have problems again so he doesn't want to risk his nice new engine so brings it to us. First thing we do is get it on the dyno and there's no doubt it produces the power, 270bhp but the tech2 logs show its on the brink of detonating all the time, on the road it starts to pink at higher rpm, thats running 22psi and its basically a hand grenade waiting to happen.

Sorry but this completely and utterly wrong (we want to keep this forum factually acurate for users). You cannot see knock retard (i.e. the effect of detonation) with Tech2 for Motronic 1.5.5 as Tech 2 doesn't support this for Z20LET engine. We know in Data List 2 on Tech 2 it lists knock retard on each cylinder but the values always stay at 0. We've seen cars detting and still the value remains at zero and this has never changed to the point of the latest Tech2 update and TIS. To monitor knock retard on this ecu you have to use separate data logging software such as K-2000

This function is enable for the later canbus equipped Astra H LEL/LER/LEH turbo engines running Motronic 7.6.x

There's two sides to every story, sometimes more , but this how we see it. Hope this helps presents a balanced view.

[Thorney]

TMS cars cetainly do not run lean, if that was the case then there would be engine blows everywhere and there have been none (and we've done more VXT's than the rest the tuners combined) Nice to see you reflect the fact that increasing boost does shorten turbo life, I'd hope that owners are given that information before you remap to 18psi. I'm happy with running them to 16psi and no further, especially as we get near identical power (the website charts are being updated).

[Joe-Turbo]

this makes great reading guys what happened to that tms/courtenay RR shoutout thing that was mentioned

[jambar]

I started this topic yesterday and have only just looked at it and wow what a response! was wondering if TMS and CMS guarantee any of there work?

[Thorney]

3 years unlimited miles.

[ikarl]

3 years unlimited miles.

speaks for itself surely

[jambar]

3 years unlimited miles.

so if I had the stage 2 done in the next few weeks what exacly would your guarantee cover

[Code Monkey]

3 years unlimited miles.

Out of interest what does this cover?

Statement like this could suggest that I take in my 3 year old car 70,000 miles on the clock just outside Vxl warrenty get remapped and now have 3 years unlimited mileage warrenty on the work covered by yourselves?

Now if the turbo fails, at what point is it proven that it is due to the wear and tear and age of the turbo and not due to the re mapping completed?

Not throwing stones, just a statement like that cast out into a public forum makes for one hell of a big birch rod to ensure you remain as your avatar states.....

I am looking at going to Stage 2 on my Turbo, but curious on the new exhausts, so will wait for info on those first but for now will get some popcorn and read on.

[Jon]

Nice to see you reflect the fact that increasing boost does shorten turbo life, I'd hope that owners are given that information before you remap to 18psi. I'm happy with running them to 16psi and no further, especially as we get near identical power (the website charts are being updated).

Remapping ANY car to any increase boost level over standard be it Vauxhall, Audi, BMW, whatever, will when used hard for extended time reduce life expectancy, its a fact understood by most and easy to comprehend given the facts, however this can be offset by using better quality oil, increasing your oil change cycle and paying more attention to warm up and hot stop procedures.

However to put his into perspective, with the overboost value of 18psi we are running this turbo at only 50% of is maxmum turbo speed and you are running at 38% of its maximum speed however the over boost is momenterilly and not the stable - held boost. But so everyone is in the picture we are both running a held boost that is much much closer to the maximim turbo speed at 5500 rpm in order to achieve the 240/250power rating we are both quoting. Therfor the overboost is not going to manifest its-self as the main contributary factor that you are suggesting.

[Winstar]

3 years unlimited miles.

Out of interest what does this cover?

Now if the turbo fails, at what point is it proven that it is due to the wear and tear and age of the turbo and not due to the re mapping completed?

Agreed one major fault of the std turbo is cracking the intergrated manifold, the cracking is always due to thermal stress and cycling does this then make you liable for replacing the turbo if a manifold cracks as an increase in power will increse the temperature of the exhaust gas? or is this warrenty only valid as part of the manufactures warrenty?

[andyr]

A bit scary that the two best known tuners for our cars cannot agree on some fundamental issues. I went the Courtney route and am overjoyed with the results and service given, I chose them simply because they have been tuning Vauxhalls for a longer period and despite this I haven't found anyone with a bad word to say about them. I'm sure both tuners have component failures from time to time - it would be interesting to know (but impossible to find out) the % of failures from each tuner?

[LY_Scott]

Interesting and welcome debate.

[Thorney]

The warranty covers the work we do and any resulting failure. With things like mainfolds (which can crack even on standard cars) then the warranty will cover the part with a negotiated price on replacement. For example, if we remapped a 10k turbo and the turbo failed we would replace the turbo completely and no charge to the customer. If we remapped a 50k car and the turbo subsequently failed we'd replace the turbo and split the bill. I think the two companies do agree (and Jons post on held boost being more of an issue than overboost is completely correct) but we just have different levels of margin I guess. We also do different things on mapping to them that don't involve boost to such a great extent.

[LY_Scott]

what happened to that tms/courtenay RR shoutout thing that was mentioned

This would be a great event to have at the National this year, before food and cage fighting lol

Edited by LY055SCO, 18 July 2007 - 04:10 PM.

[jambar]

The warranty covers the work we do and any resulting failure. With things like mainfolds (which can crack even on standard cars) then the warranty will cover the part with a negotiated price on replacement. For example, if we remapped a 10k turbo and the turbo failed we would replace the turbo completely and no charge to the customer. If we remapped a 50k car and the turbo subsequently failed we'd replace the turbo and split the bill.

I think the two companies do agree (and Jons post on held boost being more of an issue than overboost is completely correct) but we just have different levels of margin I guess. We also do different things on mapping to them that don't involve boost to such a great extent.

I notice that CS2 is about £150 less than what TMS charge, how come?

[siztenboots]

The warranty covers the work we do and any resulting failure. With things like mainfolds (which can crack even on standard cars) then the warranty will cover the part with a negotiated price on replacement. For example, if we remapped a 10k turbo and the turbo failed we would replace the turbo completely and no charge to the customer. If we remapped a 50k car and the turbo subsequently failed we'd replace the turbo and split the bill.

I think the two companies do agree (and Jons post on held boost being more of an issue than overboost is completely correct) but we just have different levels of margin I guess. We also do different things on mapping to them that don't involve boost to such a great extent.

I notice that CS2 is about £150 less than what TMS charge, how come?

TMS included dancing girls

[Joe-Turbo]

The warranty covers the work we do and any resulting failure. With things like mainfolds (which can crack even on standard cars) then the warranty will cover the part with a negotiated price on replacement. For example, if we remapped a 10k turbo and the turbo failed we would replace the turbo completely and no charge to the customer. If we remapped a 50k car and the turbo subsequently failed we'd replace the turbo and split the bill.

I think the two companies do agree (and Jons post on held boost being more of an issue than overboost is completely correct) but we just have different levels of margin I guess. We also do different things on mapping to them that don't involve boost to such a great extent.

I notice that CS2 is about £150 less than what TMS charge, how come?

TMS included dancing girls

dam, they must of been off sick when i had mine done