Over cooling a SC or turbo engine

where there's an up, there's always a down - if you monitored turbine speed you would certainly see an increase, which depending on how close to the limit you are may or may not cause problems. This may also move you onto a less efficient part of the map, depending on whereabouts you are operating. This in turn means that you need better intercooler as the compressor outlet temp has increased.

It's not such a concern over here, but if you ever take a car to any altitude, any increase in turine speed will cause a serious torque derate. they're generally set right on the limit from the factory in terms of turbine speed at altitude. Any speed increase could cause serious derate and most importantly overspeed. like i said though, not really a problem in the UK

cheers,
tt

 

so pikes peak is out this year then eh!

 

tt

 

How do you work out that improved IC cooling and better flowing core (my large one) could ever mean higher turbine speed? Denser air charge and less load for torque request on motor surely? turn it up and sure more speed and more boost to the limit of the hardware.

The example on mine is no difference in power delivery or spool or lag between the CC, smaller FMIC and larger FMIC.. Significant improvement in airflow across the core, so pressure drop of the system and core is extremely important, but as you said its system design not just big or small core.

The difference is more airflow thru the engine now, beyond its previous mapped for settings so its too lean now and needing a remap. larger core flows and provide much better cooling.

I think you're making it sound a lot more complicated than it needs be
Edited by: badger-bill

 

Bill just don't mess with the tramp on this, trust me

 

how does the wastegate work? - it's a pressure differential device that works from manifold pressure. at a certain MAP the pressure differential across the wastegate diaphragm will overcome the spring force and open the wastegate so that the desired boost level is maintained (ignoring all the PWM signal modulation of the wastegate signal to change boost curves, this is what basically happens).

a larger IC core = larger pressure drop than a smaller core of the same design - agreed?

this greater pressure drop will mean that your compressor will have to work harder before the wastegate opens. You will have higher compressor out pressure and likely temperature as a result.

Your final comment disappoints me Bill (especially as somebody who seems to have an appreciation of what's going on in an engine) - just because you're not measuring something does not mean it's not happening.

All I've tried to do is give the full explanation from all angles - some people like to know what's going on and don't until somebody tells them. In future I'll keep my overcomplicated 'ideas' to myself

tt

 

Mr Tramp

the forums asks as a whole that you retract the last line and continue to baffle us with the full sp


and answer me PM even if it is all toss
Edited by: prof

 

There it is again, that voice in my head...........

 

i'm still trying to work out how you get the correct and optimum setup for an application.


the tramp must have had a skin full of special brew as i can never talk that creative like that after a night out.

 

You basically said there that The Tramp doesnt know his physics........

 

i am chilled out, but i have to deal with component engineers like you all day long - they change something on the system to make it 'better' (hey bigger is always better isn't it ) and can't figure out why it isn't working. whoever said a little knowledge is a dangerous thing certainly knew what he was talking about.

you talk about designing a system but fail to recognise a wastegate as part of the system. last time i looked the wastegate was sensed from the intake side. oh i forgot that the intake side of an engine had no effect on the exhaust and vice versa.

notice in terms of IC core size i mentioned 'of the same design' purposely. yes the core may choke if it was undersized, but last time i looked the cross sectional area of most cores was larger than the adjoining inlet/outlet ducts so surely it would choke there first?

and i know that alternative core designs/end tank designs can have a large effect, but that's not the question here (overcomplicating? touche). if you stick on a larger core with better designed end-tanks of course it will have a beneficial effect.

so you're basically saying that a core with a larger wetted interior surface area will have a lower pressure drop than a similar design with a smaller core... fair enough, your grasp of the subject leaves me in no doubt that it's not worth arguing with you.

we'll have to agree to disagree ~ i'll keep doing what i do as a job , you keep playing with your car and oversized ICs

tt

 

Good post guy's...

Heres one for you....

I have may Rallye IC running back words from a flow point of view on a swept volume of 2966cc and running a T04e turbo and the consistent inlet temps sitting on the rollers with a good amount of heat soak was between 29 to 34 deg. This is lower than a standrd VR's inlet temp. This in my book tells me that the standard VW item is fit for purpose. It may not look sexy but it does the job...

 

Well mr TT.. what can I say...
Oversized IC? I think not... track use, logged temps during development and factual sizable reduction of in induction temps, whilst increased flow across the core, more even distribution of air within the core to heat exchange and all with less pressure drop to boot.
Yea.. I obviously know nothing Oversize you say? Clearly you know nothing about my particular engine, but feel free to criticise..



YOU dissapoint me.. patronising berk

 

small core vs large core in the pictures posted.. I have facts of the performance differences... no matter what physics calcs he would like to run..

 

'component engineers like me'.... ??

You sir are a generalistic & ignorent
Wide old broom your sweeping with there!
Edited by: badger-bill

 

there there now. Obviously some words sounding more patronising in written format than they would when said face to face

Bill did you check TTs CV recently............
Edited by: prof

 

go Bill, go Bill, go Bill, go Bill, go Bill,


the real question was how do you work out a good size intercooler


for an application? but as you all know, you all ways lose some


reliability when tuning an engine but i would rather change a turbo


than over cook the internals. all TT's on about is over working the


turbo then so be it. then you can move on to the next upgrade

 

From what I can see (I know nothing really), air squashes, if you have a massive ic, there`s more air in it, therefore more to squash, so some of the turbine output is wasted sqashing rather than pushing. A big ic flowing the same volume of air as a little one will have a lower air pressure, so to get the pressure back up the turbo will have to work harder (maybe too hard?).

Could be talking tosh, but I would have thought a bigger i/c with more air in it would hamper the throttle responce, unless the turbo can work harder to shift more air?

 

there is not a lot more air to squash having a bigger i/c but the i/c cools the air makingthe airdenser so the mass of air isgreater e.g: more air to burn in the cylinders
Edited by: danmoody