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Davezj
04-06-2013, 11:17 PM
I have a question for you guys,
we all know if you up the boost you have to ensure you can supply enough fuel to keep the AFR's to the correct and safe value.
but if you can ensure you can do this and you have no knock, what boost pressure can you run.

if in a theoretical scenario you can supply as much fuel as you want can you just disconnect the boost control and let the boost go as high as the turbos can create.
if you can do this without knock is there any down side to doing this.
is it bad to run a turbo at max pressure. i know the inlet temps will go up running at max pressure. but is that it

what do you guys think is it safe to do it.
i know it can be done, because i have tried it, but is it safe to do, as long as AFR knock is OK.

adaxo
04-06-2013, 11:51 PM
I think, the one of the main boost control job is to keep stable/similar boost level at desired rev range.

wintertidenz
05-06-2013, 12:42 AM
You would probably end up with the turbos spinning a bearing or coming apart. Ours are designed to go up to 230,000 RPM if I remember correctly - any more than that and I'd say you would end up with a loud BANG and shreds of turbo through your engine.

Davezj
05-06-2013, 05:11 PM
Has anyone logged inlet temp with respect to boost levels.
When I say inlet temp I mean throttle body inlet temp, e.g. Boost pressure temp, not outside inlet temp from evoscan.

At what boost pressure do the turbo go out of there efficient operating range.

exevoowner
05-06-2013, 08:47 PM
I was lookind at doing some kind of temp prob on the inlet side of the intercooler as i have a little controler that can run 2 probs on it just to see what the intake temp was but havnt got round to fitting it yet lol

Humpty's Revenge
05-06-2013, 09:03 PM
Has anyone logged inlet temp with respect to boost levels.
When I say inlet temp I mean throttle body inlet temp, e.g. Boost pressure temp, not outside inlet temp from evoscan.

At what boost pressure do the turbo go out of there efficient operating range.

If this is correct it might help but obviously different engine

I've got an air charge gauge which is got it's probe right in front of the throttle body

It read in the Winter 9 degrees now it's warmer it's reading 25 degrees both times when driving

My boost is set at 0.80

This probably isn't what you are wanting to know Dave ?

swinks
05-06-2013, 09:31 PM
At what boost pressure do the turbo go out of there efficient operating range.
Get yourself TD03 flow chart and you will see that it's approx. 1.2 bar ;)

swinks
05-06-2013, 09:40 PM
if in a theoretical scenario you can supply as much fuel as you want can you just disconnect the boost control and let the boost go as high as the turbos can create.
if you can do this without knock is there any down side to doing this.
is it bad to run a turbo at max pressure. i know the inlet temps will go up running at max pressure. but is that it

what do you guys think is it safe to do it.
i know it can be done, because i have tried it, but is it safe to do, as long as AFR knock is OK.
Few times I've read statement above and couldn't believe you are serious... ;)
Dave, gonna give you few hints to think again:
- you have following chain of happening: boost selenoid > wastegate actuator > wastegate release flap in hot side turbo. Guess why?
- turbo may produce massive postive pressure, but it doesn't mean increse in air flow
- engine hasn't got unlimited capacity
- with no bypass control of spinning turbo how you gonna balance boost with throttle body butterfly flap opening/closing
- level of pressure in cylinders vs. ignition/burn fuel mixture vs. stength of engine components
And many more.

Just any basic article about wastegates, boost selenoids, turbochargers etc. will answer your question... :)
In other words: NO. It's not safe.

Davezj
05-06-2013, 09:42 PM
I thinking maybe swinks might have some temp data as he has done a lot work with charge temp reduction with his water meth injection kit.

Davezj
05-06-2013, 09:53 PM
Beat me to it.
I will consider all your comment tomasz.

Davezj
05-06-2013, 11:37 PM
i am not being funny here my responses are serious questions/comments. it is just how i thought i understood the way things work./Hmmm
i have only put my reponces in red to make them stand out not to imply an tone or harshness i am only after information.:d

Few times I've read statement above and couldn't believe you are serious... ;)
Dave, gonna give you few hints to think again:
- you have following chain of happening: boost selenoid > wastegate actuator > wastegate release flap in hot side turbo. Guess why?
i believe it is to reduce the boost from running at max 100% of the time, as not many fuel systems can keep up with full boost of a turbo and maintain correct AFR's , to make the boost lower so adverse effects can be kept in check if you don't have things in place to combat them.

- turbo may produce massive postive pressure, but it doesn't mean increse in air flow
i can see what you are saying but why is this the case? is it just down to charge temp, or is something else involved.

- engine hasn't got unlimited capacity
I presume you are talking about the cylinder size, if that is the case then surely the higher the boost pressure the more air is going into the cylinders, but you would have to consider higher charge temps when running at the extreme of turbo efficiency. so hypothetically, actual values are wrong obviously but it is just to make a point, would a boost pressure of say fixed quantity of air @1.0bar @ 20deg C be equivalent to the same quantity of air @60 deg C @1.5bar the increase in pressure is due to the change in temp not because there is more air in the fixed space, if that makes sense.
however if the charge temps are the same at 1.5bar then surely that would mean 50% more air is getting into the cylider than at the same charge temp @1.0bar/Hmmm/Hmmm/Hmmm/Hmmm

- with no bypass control of spinning turbo how you gonna balance boost with throttle body butterfly flap opening/closing
i don't get what you are saying, when the throttle body closes the full boost is dumped out the BOV. the only thing the that will happen if the wastegate remains closed is the boost will build as hard and as fast as the turbo can make it, no wastegate creep or any other limitation introduced by the boost control system. When you go to WOT the turbos will be creating the max amount of boost they possibly can, any boost control applied to the max boost level will only reduce this max you can't add more boost with a boost controller you can only take it away/limit it.

- level of pressure in cylinders vs. ignition/burn fuel mixture vs. stength of engine components
this is something i am not sure of at all, as i have no previous info on how strong the 6A13TT engine is, but it does concern me slightly.

And many more.
i do appreciate you input on this tomasz, as i know you you have looked into charge cooling in quite a bit of detail.

Just any basic article about wastegates, boost selenoids, turbochargers etc. will answer your question... :)
In other words: NO. It's not safe.

i will go amd try and find some boost wastegate reading on the net.
so don't flame me too hard :d
i will go and do lots of /Hmmm/Hmmm/Hmmm/Hmmm/Hmmm and possibly /duh

Davezj
05-06-2013, 11:39 PM
Get yourself TD03 flow chart and you will see that it's approx. 1.2 bar ;)

i have been searching for one on here, i know there is one on here some where but i can't find it.

i have been useing compressor efficiency map chart td03 flow chart all combinations of these and i have not found it yet.