Turbo's and boost pressure.

[Czar]

Good morning gentlemen,

Firstly, let's see if we can keep this thread on topic, as the title suggests, we will be discussing only the THP turbo and boost pressures.

The very reason I have started this thread, is my PM inbox not only here but on the Peugeot and BMW MINI forums sees the same relative questions, time and time again.

I suffer boost cut, why ?

How much boost pressure can I run ?

What's the safe boost limit ?

Can I swap turbo's ?

Etc etc etc, you get the idea.

I'm currently out of my office and don't have some relative information to hand, please be patient, I will amend or edit at a later date.


Now I've opened this interesting can of worms, let the discussion begin.

[BeefMasta]

Welcome back. Looking forward to your update

[Gazski66]

+1 ^^^

[Jimbob]

Will more turbo boost make the DRL's stay on at night?

JB

[Czar]

Welcome back. Looking forward to your update

+1 ^^^

Thank you,

Hmmm not quite sure just where to begin, understanding the turbo, the reason a specific turbo was chosen through calculations, to in this case perfectly match the THP engine, requires a very good understanding of equational mathematics, that said, as that has all been calculated for you by the relevant manufacturers, which is why your particular THP engine is matched to it's calculated specific turbo.

Now, before we get ahead of ourselves, we need to ask ourselves, when you think about "tuning" your chosen THP variant engine, just how much do you actually understand about your THP variant engine, the calculated matched turbo and it's compressor efficiency map, and most importantly, how much does your chosen "tuner" understand about your THP variant engine and it's calculated matched turbo ?

It's all very well your "tuner" increasing the boost target figures, in order to satisfy your need for those all important HP/torque calculated figures, for bragging rights on the forum, at meetings and down the pub, your chosen "tuner" will NOT stand the cost of any engine damage sustained, from their re-mapping ("tuning")

You have to be aware, anytime you alter the factory settings, you are asking for trouble, and when it goes wrong, and it will, you'll be looking to blame anyone but yourselves !!

That'll do for now.

[Chris_Blue]

Jamieeeeee ......LOL

ED- Anyway for my tuppence as a Layman, whats wrong with running a Turbo at maximum efficieny, and the THP base engine is rated at well over 200BHP as it is on the Racing and other vehicles

[Superfly Guy]

Its all gone a bit silent.

[Czar]

Jamieeeeee ......LOL

ED- Anyway for my tuppence as a Layman, whats wrong with running a Turbo at maximum efficieny, and the THP base engine is rated at well over 200BHP as it is on the Racing and other vehicles

Nothing wrong with running maximum efficiency, just how long running maximum efficiency will the turbo last ?

This is the very point, the turbo has a relatively small window of pressure ratio/volumetric efficiency, approximately 78% as you guys increase the boost pressure, the efficiency and more importantly the reliability begin to decline, you can only squeeze X amount of pressurised air volume into a given diameter tube or engine cylinder.

Once you exceed the calculated volume limit of a dimensional tube or engine cylinder, you get a chocke situation, you've reached the dimensional tube or engine cylinder fill volume, this choke situation now creates a very high pressure within the same given dimensions of the tube and engine cylinder, the pressurised air is now beginning to stall the air flow being created by the increased boost pressure from the turbo, which is now pumping outside of its pressure ratio matched volume flow efficiency, which in turn puts huge shock pressure loadings on the exhaust turbine wheel, shaft and compressor wheel.

This ever increasing very high pressure (sonic) shock loadings from working at maximum and over efficiency pressure ratio's, not only reduces the life of your turbo, it also reduces the life of your engines internals too!!

Its all gone a bit silent.

I can't be on the forum all the time, sadly work gets right in the way.

[Superfly Guy]

I can't be on the forum all the time, sadly work gets right in the way.

Well 10/10 for the grand entrance anyway.

[Gazski66]

Nothing wrong with running maximum efficiency, just how long running maximum efficiency will the turbo last ?

This is the very point, the turbo has a relatively small window of pressure ratio/volumetric efficiency, approximately 78% as you guys increase the boost pressure, the efficiency and more importantly the reliability begin to decline, you can only squeeze X amount of pressurised air volume into a given diameter tube or engine cylinder.

Once you exceed the calculated volume limit of a dimensional tube or engine cylinder, you get a chocke situation, you've reached the dimensional tube or engine cylinder fill volume, this choke situation now creates a very high pressure within the same given dimensions of the tube and engine cylinder, the pressurised air is now beginning to stall the air flow being created by the increased boost pressure from the turbo, which is now pumping outside of its pressure ratio matched volume flow efficiency, which in turn puts huge shock pressure loadings on the exhaust turbine wheel, shaft and compressor wheel.

This ever increasing very high pressure (sonic) shock loadings from working at maximum and over efficiency pressure ratio's, not only reduces the life of your turbo, it also reduces the life of your engines internals too!!




I can't be on the forum all the time, sadly work gets right in the way.

So would i be right on saying that getting a better after market turbo will not really be any better as the engine cylinder can only handle so much air volume?
Sorry if its a daft question but do not understand turbo's to well

[Superfly Guy]

With any form of engineering there are two constants.

1 You can never get something for nothing.
2 There will always be a bottleneck.

[Gazski66]

With any form of engineering there are two constants.

1 You can never get something for nothing.
2 There will always be a bottleneck.

I get it in the neck from the mrs for nothing

[Ragnarok]

Czar, mind sharing me that pressure map for Racing turbo we discussed a while ago?

Anyhow, looking at limitations. MAP sensor can only handle boosts up to ~1.55 bars. Exceeding that will very likely require a manual boost controller... seems no-one has figured out how to pass that in ECU.
Everything else regarding engine lifespan, etc. It's always a tradeoff, you want something, you have to give something. Simple. My turbo runs at 1.3-1.6 bars and I am aware it might reduce the lifespan.

[Jimbob]

I get it in the neck from the mrs for nothing

Great answer!

JB

[Chris_Blue]

If remapping the ECU, best to not go for max psi then. Bout 85% could achieve better results, and be more helpful to the lifespan of the OEM turbo
Just fit an uprated Turbo i guess