Limp mode temperature?

drummerdimitri

Registered User
I reached a maximum of 120 C when driving as quickly as possible up a mountain during the summer weather and after having installed my tuning box I reached around 125 C and the car went into limp mode.

I can tell the box is doing its job but how can I prevent the limp mode? I'm guessing an upgraded inter cooler will do the job otherwise what is the maximum permitted temperature for normal operation?

I thought the car would go back to normal when the temp dropped to around 100 C but turns out I had to turn the car off and back on for it to work normally again.
 

veeeight

I am a very pretty girl
VCDS Map User
It's not really important, your temperature readout is the oil temp - different to the temperature in the combustion chanmbers.

If your car is going into limp mode then the combustion chambers are already at dangerous levels. It doesn't really matter what your oil temp is saying.

Back off the boost. The ECU is already trying to protect the engine.
 

drummerdimitri

Registered User
It's not really important, your temperature readout is the oil temp - different to the temperature in the combustion chanmbers.

If your car is going into limp mode then the combustion chambers are already at dangerous levels. It doesn't really matter what your oil temp is saying.

Back off the boost.

Would it be bad to keep going into limp mode once a week say?

I would need an ungraded inter cooler otherwise correct? Otherwise drive hard for shorter periods of time.
 

veeeight

I am a very pretty girl
VCDS Map User
What octane fuel are you using?

Personally, I would back off the boost setting in the box. Or buy a more powerful car :)

By going into limp mode regularly, You are introducing more thermal fatigue into the engine and components.
 

S32B

Registered User
Sorry don't normally post like this but:

If I go to the gym and push myself that hard I end up collapsing on the floor, would that be a bad thing to do again and again?

Not being funny, but I hope it's a good analogy ;)
 

drummerdimitri

Registered User
What octane fuel are you using?

Personally, I would back off the boost setting in the box. Or buy a more powerful car :)

By going into limp mode regularly, You are introducing more thermal fatigue into the engine and components.

I am using 98 RON fuel which is the highest octane available here.

I will try reducing the boost to see if it makes the thermal issue go away. A more powerful car is not the answer since there is nothing out there that will satisfy my wants. Nothing I could ever afford anyway.
 

veeeight

I am a very pretty girl
VCDS Map User
If I go to the gym and push myself that hard I end up collapsing on the floor, would that be a bad thing to do again and again?


What doesn't kill you, makes you stronger ;)
 

Rob2k68

Well-Known Member
VCDS Map User
Kelly Clarkson fan lol ???
 

steeve

Registered User
The engine cooling system will have been designed to manage a car with 300 bhp increasing the output increases the heat generated (more power equals more heat) and in extreme conditions which wouldn't affect a standard car may push a modified car over the top.
If you push it to temperatures past what Audi continue safe then there's a good chance it may affect reliability.
 

jetron

Registered User
"I'm guessing an upgraded inter cooler will do the job"
Surely upgrading (the performance of) the inter-cooler would only make things worse by making it run even leaner and only aggravate the perceived problem, hastening the impact on reliability?
 

S3Alex

Rarely neutral
Gold Supporter
Upgrading the intercooler will not aid engine cooling.
It cools incoming air from the turbo.

I'm amazed you managed to get the engine up to those sort of temps but expect that running high boost on a small turbo is giving you very high chamber temps and EGTs

I am running a stock cooling system on a 550bhp car which never got beyond 100c on a track day and the point of saying that is that the cooling system is adequate if you don't do silly things with the engine.
A small turbo pushed hard without proper setup and ancillaries results in a hot engine.

You need to back off the boost.
 
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steeve

Registered User
Mountain, thin air, perhaps not getting enough airflow through the radiator, high revs, high load, relatively slow speeds?

Not like a track day perhaps where speeds are high.
 

S3Alex

Rarely neutral
Gold Supporter
Mountain, thin air, perhaps not getting enough airflow through the radiator, high revs, high load, relatively slow speeds?

Not like a track day perhaps where speeds are high.

Not quite my point Steve.

I'm trying to remind dmitri that flogging a small turbo on high boost with all the attendant heat issues from high chamber and EG temps is the cause.

No doubt thin air doesn't help but basically it's being worked way too hard.

He needs to reduce boost and consider things like WMI and so on if he's going to try this again.

It's possible to run more power with less boost and lower EGTs if the turbo is adequately sized etc.
 
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