GUIDE REQUEST for turbo map

[Piggy]

I will happily hold my hands up and say when I am in over my head....rather learn stuff than get stuffed.

so....
I am getting to understand some of a turbo map...optimum boost and efficiency...

but can someone in the know put a guide in how to read it properly???

thanks ahead
Piggy

[cwspellowe]

BOOM!

Pretty much everything you need to know. Some figures will be estimates, but take the time to read it. There's links to a calculator for your CFm at given RPM too, but you need to enter volumetric efficiency for the engine which noone can say for definite.

Helps give you an idea of what to look for though

[Eeyore]

what software do people use the write and modify maps anyway? wouldnt mind knowing how to do it myself!

[Dan!]

what software do people use the write and modify maps anyway? wouldnt mind knowing how to do it myself!

O.o dafuq

[cwspellowe]

what software do people use the write and modify maps anyway? wouldnt mind knowing how to do it myself!

Quoted for the epic fail

[Jonny81191]

what software do people use the write and modify maps anyway? wouldnt mind knowing how to do it myself!

You've missed the point here sam

[Eeyore]

exactly i have literally no idea and want to know how its done D:

[cwspellowe]

Me too, but that's another thread for another day

[Piggy]

nice one

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as a second question....vaccuum actuated turbos...where the actuator is inbetween hot/cold sides...can that be controlled with a MBC?!?!

[Eeyore]

ahhh i have been educated. my bad. Now im just baffled as to how anyone makes a turbo map D:

[cully]

? at this thread
/confused

[cwspellowe]

nice one

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as a second question....vaccuum actuated turbos...where the actuator is inbetween hot/cold sides...can that be controlled with a MBC?!?!

Think you've misunderstood something there mate.

All the actuator does is control the wastegate flap, either by a vacuum or boost signal.

A boost actuator pushed the wastegate open as boost pressure rises. A vacuum actuator allows the wastegate to move depending on the vacuum solenoid.

Are you talking about VNT's or wastegated turbos?

EDIT again..

I presume you're looking at VNT's where the vacuum actuator is physically located next to the CHRA and the flapper it controls is in the middle? They work a completely different way to wastegated turbo's and are much more complex than simply running an MBC. For a start, an MBC only works in boost applications, in a vacuum application it wouldn't let anything through as they need the air pressure to push a valve open, a vacuum would hold it shut. Also, VNT's work by controlling vane angle in the hotside of the turbo to generate varying levels of boost dependent on load and rpm's. If you fit one of them without any method of properly controlling the vanes something will die very quickly. They don't use a wastegate to bypass the turbine completely, their equivalent is to open the vanes up to decrease resistance in the turbine and build less boost

Strap one of them onto an XUD and use a boost actuator as with a wastegated turbo and you'll build boost exponentially until something dies.

[Piggy]

as i thought....

just an earlier post on this thread gave me the impression that a VNT was being controlled that way...I am avoiding them due to huge complex control system needed...

saturday night...tired and dazed...thanks for clear up

[cwspellowe]

VNT's can be controlled by vacuum and boost actuators. But you don't just strap one on and expect it to work right.

[Piggy]

no no I know that! lol!

Im loving the CFM calculus....getting me right back to school...feel like I need a blackboard!!!

Thanks for that...

fully controlled VNTs on a XUD would need boost sensor, throttle sensor, vaccum actuator etc?? and a ECU to run all that?!

[cwspellowe]

Not necessarily..

There are mechanical ways to control it too, have a read up of the VW forums and you'll see some interesting setups

[Piggy]

sounds way too much effort...esp when the gt1752 or 2056s does the job without being a migrane

by those calculus a td04L would be a bad unit for the 2.1...way out of efficiency zone and beyond surge limit too

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...I maybe going wrong in one area....engine volumetric efficiency...I assume its a different percentage than petrols???

if so...how much different?!

[cwspellowe]

Being "out of efficiency" isn't a completely bad thing, a T2 for example will be way down below 60% efficient at 30+psi but people still do it, there's no black and white rule. If you can get 70% efficiency or more then you're onto a winner.

The TD04 though is used on XUD's because it's bombproof, can withstand high PSI and it matches a gov modded XUD's rev range quite well. On a 2.1 I can't see the revs being raised that much as it's a much lazier engine, so the powerband would be quite narrow i'd imagine. People on here with TD04's make good boost way up to 5k+rpm, something I don't think the 2.1 would like. So say it builds boost by 2.5krpm, and your gov cuts in at 4krpm, you only get 1500rpm of usable boost. On a 1.9 you'd get more like 3k of boost.

[Piggy]

exactly why my very nice td04L is for sale as is my T2 to fund a GT series turbo...

I want it starting on boost sooner, say 2k, and happy to go to 4500...especially after a rebuild and port polish etc etc

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PS and fitting a hdi box for the longer gears!!! extend that torque map!!

[cwspellowe]

GT should fit in nicely then sir. Even look at a GT2052, bit more common than the 56 and slightly smaller compressor wheel as it won't be needed to flow as high at the top end.

Port and polish I wouldn't bother with so much, port match to the gaskets by all means but no need to go overboard.

[Jonny81191]

Being "out of efficiency" isn't a completely bad thing, a T2 for example will be way down below 60% efficient at 30+psi but people still do it, there's no black and white rule. If you can get 70% efficiency or more then you're onto a winner.

The TD04 though is used on XUD's because it's bombproof, can withstand high PSI and it matches a gov modded XUD's rev range quite well. On a 2.1 I can't see the revs being raised that much as it's a much lazier engine, so the powerband would be quite narrow i'd imagine. People on here with TD04's make good boost way up to 5k+rpm, something I don't think the 2.1 would like. So say it builds boost by 2.5krpm, and your gov cuts in at 4krpm, you only get 1500rpm of usable boost. On a 1.9 you'd get more like 3k of boost.

Exactly why I'm not using a TD04 on my HDi

[cwspellowe]

Just raise the rev limit and stop being a bumder, you already have HDI rods

You using that TD5 blower then matey?

[Piggy]

can I ask again as an idiot....is volumetric efficiency different for diesels??

as all my calculus are showing even GT series to be way outa efficiency for what I need.

PS yeah, been looking a GT2052 or 1752. but the maps say 2052 so far

PPS I will probably only port n polish exhaust side as theres 2 inlet valves but the single exhaust valve is still small...
I gasket match as routine anyhow too.

[cwspellowe]

can I ask again as an idiot....is volumetric efficiency different for diesels??

as all my calculus are showing even GT series to be way outa efficiency for what I need.

PS yeah, been looking a GT2052 or 1752. but the maps say 2052 so far

PPS I will probably only port n polish exhaust side as theres 2 inlet valves but the single exhaust valve is still small...
I gasket match as routine anyhow too.

I'd take a punt at a VE of 80-85% for a clattery old XUD, higher for an HDI. Is the 2.1 a 12v motor though? Go for 85% and see how that works out.

Unless you know the EXACT VE of the engine though you'll never get a 100% accurate comparison. At that point you just go and fit it and see what happens, having decided what looks best given your tolerances.

[Piggy]

fair enough...I was going by 90...and getting odd results...85 makes more sense.

yeah 12valve

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thanks again for all the help...
you are looking for a 2056??...I will try and spot one for you...

the fun part now is working out all the vehicles that the gt2052 runs on...as not many list a turbo by its ID number!!!

[Piggy]

with VE at 85% and a GT2052 @ 20psi...

looking at good efficiency... 68%-72% between 2k-4k rpm

25psi seems to push it way off the map...no wonder you killed your GT...twice!!!

[David]

with VE at 85% and a GT2052 @ 20psi...

looking at good efficiency... 68%-72% between 2k-4k rpm

25psi seems to push it way off the map...no wonder you killed your GT...twice!!!

Haha

[cwspellowe]

with VE at 85% and a GT2052 @ 20psi...

looking at good efficiency... 68%-72% between 2k-4k rpm

25psi seems to push it way off the map...no wonder you killed your GT...twice!!!

Haha

To set the record straight I only killed my GT once, I just owned two GT's that were each killed once

[David]

Having any luck finding another one?

[cwspellowe]

Some luck, it's all money though. I could buy one today if I had £200 spare but i'm trying to find a cheaper one.