How much boost is safe on the OEM Turbo?

[GoMax]

I got to thinking this morning, and wondered at what boost levels the OEM Turbo runs out of efficiency.
When pushing it past that level (whatever it may be) - how does that effect reliability of the turbo etc.

I've been considering which way to go - bigger turbo, or stay with stock.
Any thoughts and comments appreciated.

- Max

 

[Hijinx]

~21psi max tapering to ~19psi redline is the short answer.

 

[GoMax]

~21psi max tapering to ~19psi redline is the short answer.

Interesting. Most COBB ProTune are running 20-21 psi, and most Tune+ tune is running 23-24 psi.
Is there any documents, papers, etc that can help me understand the risks, signs of issues etc so I can be more aware?

I'd like to be better informed when making performance decisions...

-- Max

 

[Sekred]

I got to thinking this morning, and wondered at what boost levels the OEM Turbo runs out of efficiency.
When pushing it past that level (whatever it may be) - how does that effect reliability of the turbo etc.

I've been considering which way to go - bigger turbo, or stay with stock.
Any thoughts and comments appreciated.

- Max

Typical turbo failure from continuing over speeding is compressor wheel burst. The compressor wheel splits down the centre and then tries to exit the housing.
Failure of the friction weld between the turbine wheel and shaft can also occur but this is pretty rare from my experience.

 

[Hijinx]

Interesting. Most COBB ProTune are running 20-21 psi, and most Tune+ tune is running 23-24 psi.
Is there any documents, papers, etc that can help me understand the risks, signs of issues etc so I can be more aware?

I'd like to be better informed when making performance decisions...

-- Max

I'd rather direct you to one of the tuners for more in depth information. They're all pretty good guys and don't mind answering questions when they've got the time.

 

[GoMax]

I'd rather direct you to one of the tuners for more in depth information. They're all pretty good guys and don't mind answering questions when they've got the time.

Hijinks,

I'm working with Adam, and have been very pleased with the tune and all my interactions. I was just wondering what my risks were if I'm choosing to drive the turbo outside its performance envelope.
Perhaps that means an early replacement at 30,000 Miles, or perhaps never?

Does anyone know where we can get the flow data from the Borg Warner KP39 (our OEM turbo I believe)?
I'd like to see how far outside the envelope at 23 psi tune is compared to 21 psi.

Wish I knew more about Turbo Charger design!
-- Max

 

[RAAMaudio]

Some turbo failures can take out the engine and all coolers, pretty costly issue if that happens.

If you want more but stay within a tight budget Cyborg is the way to go and have a far more usable power band instead of diesel power band.

 

[hydrix]

Hmm interesting. I have a stock turbo, basically everything stock and running an e30 tune from tune+. I consistently see 26psi on a daily basis. I wonder how long this can go on until I see serious consequences.

 

[RAAMaudio]

I do not think anyone as blown a stock turbo yet so no way to really know and it would take a few of them to start getting useful data on it.

One thing to consider is doing all the bolt on parts and running a tune on the stock turbo cost a bit of money and a good chance no warranty if it blows and worse if it takes out other parts. Leaving you stranded someplace, in a hotel, towing fees, etc......it can get pretty costly.

A Cyborg turbo will fix the donkey kick, falls on its face stock power curve, and likely not induce turbo failure by over driving the stock unit.

The car will be much nicer to drive all the time and faster, nice benefits and not that much money.

 

[Sekred]

We really need a compressor map for the KP-39, then you do some calculations and work out whats going on. If your operating to the right of the Choke line then its bad news.
http://www.turbobygarrett.com/turbobygarrett/choke_line

 

[jtsimaras]

Probably safe to say Motor will pop before turbo?

 

[15pbfist]

Ran 28-29psi on stock with 93 & meth

 

[Sourskittle]

I made 354ft. Lbs on torque on a stock turbo at 29.4psi peak. That was at like 2850rpm though... Basically all the cyborg turbo system, minus the actual turbo. And... The car was not tuned for it since I was only running the stock turbo a few days at a time.

I have an interesting question... Besides wikipedia, where did we get the info that this is a "KP39"? I'm having a hard time remembering.

Ok... Change your oil, and this turbo isn't going to give you any issues until you make one. Don't run it without an air filter, don't use crappy, or even worse, dirty oil. Don't drop a bolt down it.

The compressor maps will tell you a lot. But at the end of the day, its about what it does on OUR ENGINE, in OUR CLIMATE. And if tune+ or who ever is getting it to its best combined power with 20psi or 25psi, then that's where its good at on the fuel your using with the timing your running with the intercooler you have. So trying to sort of go backwards and read a map on "how to get there" is kind of silly, when.... Your already at your destination. If you wanted to upgrade fo a bigger comp wheel, THEN a map is more relevant.

Also, I mentioned this in a different thread. On top of being durable, these stock turbos are not expensive ( unless you buy a brand new one from Ford ). I mean.... How many have been sold on the forum for $350? If you told me, you could give me an extra 50lbs of torque for $100 per year, I'd take that deal. But this turbo seems to have two things going for it... Like a 58hp honda crx HF motor we had with 8psi and 125shot, this turbo seems too crappy to hurt its self. Its parts are so small ( turbine and compressor wheels ), that its hard to spin it out of control. It also has a very good little bearing package.

Honestly guys, if we didn't have the cyborg option, I'd be spraying water into our compressor nut. Its expendable, lol. Its easy to change. And besides the tow home like Rick pointed out, its not the worst thing at all that could happen. I'd be worrying about breaking the trans output shaft or something in that $2500 + core trans of ours.

 

[BoostBumps]

We really need a compressor map for the KP-39, then you do some calculations and work out whats going on. If your operating to the right of the Choke line then its bad news.
http://www.turbobygarrett.com/turbobygarrett/choke_line

This ^

Can't seem to find KP-39 a compressor map posted anywhere? This would provide some great information as to where the efficiency limits (choke point) are to ensure the stock turbo is operating within a safe reliable range when raising boost levels well beyond stock levels....

 

[Joker328]

I'm kind of surprised it's taken this long for this question to be asked on here (though maybe it has, I didn't really look). Regardless, I think it's an important one that a lot of people seem to be ignoring. Seems like people are getting a bit wide-eyed at the amount of torque they are putting down without really stopping to ask how that is happening, what the risks are, and why some people are tuning for that level of boost and others aren't. The reality is that when you go that far outside of the OEM specifications, you are all, as we say in aviation, "test pilots." Nobody really knows how this will affect failure rates of the turbo or other parts (pistons, rods, transmission). The car just hasn't been around long enough to get any real sense of what the impact is. Sourskittle makes a good point that replacing the turbo alone may not be that costly if you can snag a used one, but it's still something to factor in. The failure of other parts could be much more costly though and would almost certainly not be covered under warranty, even if they were defective to begin with.

I'm not saying people shouldn't get tunes to get the most they can out of the stock turbo, but just realize that engineers at Ford, Cobb, Mountune, etc. have established their boost limits based on lots of engineering expertise and experience about what is safe for long term reliability of the car (not just the turbo), and the further you get outside of those limits, the more risk you take on. The increased risk of failure may not be a linear relationship either (e.g., slight increase initially before sudden large increase in failure rate at a certain level), but until we get more people blowing apart their compressors in a year or two, we won't really know where that limit is. Just make sure you don't mind being the guinea pig.

 

[supercrackerbox]

I'd like to say there should be a considerable margin of safety between the levels of stock and "too far", and that is true in my experience. But the cars I'm used to playing with are literally 30 years behind technologically, so I truly don't know. So I'm interested to see what we learn here.

 

[Sourskittle]

Its we did find a compressor map for a KP39, it has a 999.99% chance of being the one for the decade old VW TDi engines that actually do use a KP39. Let's just say... The diesel KP39 doesn't share anything at all with our turbo, which begs the question.... Where did the the idea of this turbo being a "KP39" come from...? My theory is that a KP39 is smaller than a K03, and our turbo is smaller than a normal K03, hense... We must have a KP39. The mini Poopers also have a "KP39".

I'm not saying we don't have a KP39, I'm just saying, a few different cars seem to have a "KP39", but honestly, they are all fairly different "KP39's". I guess you could say there are many "K03's" as well...

I'll give you guys a useful hint... Look up a compressor map for a TD04-9B turbo from a twin turbo stealth. There compressor wheel is identical in size vs ours. Ours would be more of a 9T than a 9B or a 9G, but its all pretty close. What you find is... Bone factory stock, ford is running the wheel on the ragged edge, lol. 21psi falling to 14.5psi from the factory is a wet dream for a stealth or 3000GT owner that has a 1.5L designed in 1990. They likely have a bigger compressor cover too.

Like it or not, at the end of the day, its what can the car use/do. If tuners are running 25psi with Xxx fuel and XXX timing to get 2xx whp, then... It is what it is. If you were doing this to a GT35 turbo and asking THAT TURBO to run 10psi more than it can on any given more, THEN you might have issues. The rotating mass of a GT35 is one zillion times more relevant to speed than our tinnie-tiny little wheels.

I'll tell you this... No 3000GT on the planet will make 400-440whp with two 9B size turbos, so what does that tell us? One compressor map on two different engines can do very different things. Running the wheel/compressor past its efficiency can still be done, you just have to cover it up with a good intercooler and/or meth injection to keep it on boil with timing advance. Ford does this with direct injection. The stock turbo is DONE at 5200-5400rpm. They keep the engine making power buy flooding it with cam and ignition timing, which is only acceptable because it has an awesome ECU and direct injection. As long as the intercooler covers up for the comp wheel running past its eff at 5400rpm, then the boost can hang in a little longer and the ecu can still feed it timing. But that's why we gain so much from a nice intercooler upgrade. If we had a GT2867 from the factory, our stock cooler would actually do pretty well. We could make the same power on 15psi with no heat.

Going back to the stealth/3000gt. No vtak. No DFI. 1980's tech ecu, crappy crappy intetcoolers and they are pretty much reaching for 170whp per turbo with mods.

Put a TD04HL-20T on a 3000GT and watch the driveline parts fly !!! Lol. Spoiler, they make about 550Awhp.... What could a fist do with one ? (See where I'm going with this? )

 

[Siestarider]

I searched long and hard for a map for our stock turbo in 2014, never found one. But I am still curious. SS is probably correct as regards practical matters, his expertise and experience go way beyond mine. But I am still curious.

 

[blurred]

Doesn't anyone read their documentation ? Haha

 

[OxfordST]

I'm seeing 24-25psi daily on my tune.