Holset turbo controlled with N75 and ECU 2.5tdi

morriss · Apr 1, 2009

Going down the Holset Turbo route Hx 25 w for my 2.5tdi ACV engine... which has ecu and N75 boost control...can i control the holsets boost with the the current ecu n75 set up......

hatemi · Apr 1, 2009

Yes you can.

But... Why not use the ten other topics that you have already started on the subject. No need to start yet another.

morriss · Apr 1, 2009

I have started another thread as this is another topic ie not a VNT turbo...and thought the wider TDI community might be interested in offering an opinion....
but again thank you for your input!

morriss · Apr 1, 2009

so the ecu controls the n75 which sorts the boost? can you then add in an electronic boost controller to save have to flash the ecu to change boost settings.......

Rub87 · Apr 1, 2009

yes you can.. use map based smoke limiter.. and also I agree with Hannu that it's not necessary to start a new topic over and over again..

The holset is wastegate I assume?

Maybe it ain't a bad idea to run a 3bar mapsensor..?

apomiett · Apr 1, 2009

morriss · Apr 1, 2009

ok fair point will limit my posts to one thread

mojogoes · Apr 1, 2009

If you use a mechanical boost controller and map bleed you won't need to use a 3bar map sensor..........if this turbo is W/G'd!

Rub87 · Apr 1, 2009

mojostylez

TDIfreak · Apr 2, 2009

agree that with larger wastegate turbo you don't need 3 bar MAP or accurate boost control. Just bleed the ECU line.
Sometimes it may limp mode from underboost with stock program.

VNTs are totally different animals regarding boost control.

mojogoes · Apr 2, 2009

Rub87 said:
mojostylez

Quote........"Sometimes it may limp mode from underboost with stock program"

Very true!!......i know a guy who is using a .64 turbine housing on his PD130
hp motor with this problem........he suposidly has 300hp but last year struggled to do a 13sec because of the said underboost limp mode problem!!.......not too hard to sort but he don't want to listen.

P.S..........what is funny is that he hasn't got standard tuning/tuning

morriss · Apr 2, 2009

so basically i will be able to run the holset on my current boost control set up (ECU N75 ETC) being new to this is it possable to change the amount of boost via vagcom..or will it all be down to remaping....is there any point or is it possable to add in an electronic boost controller? Just waiting for parts to arrive its like waiting for christmas......

Rub87 · Apr 2, 2009

if you want to run a separate boost controller, you must use MAP based smoke limiter, otherwise you can only map fuel for one boost level, if you run higher boost, you need more fuel, and that is not so good possible with maf based smoke limiter..

named tintin · Apr 2, 2009

Convert a VNT controlled ECU into a wastegated one are not a big deal, like the underboost limp mode can be eleminated.

Like Rub says, for a set-up like this is better to use IQ based on Boost.

morriss · Apr 3, 2009

sorry im lost?....can you explain the smoke limiter thing maf vs map? how do thry work?

TDIfreak · Apr 3, 2009

morriss said:
sorry im lost?....can you explain the smoke limiter thing maf vs map? how do thry work?

Only a chip tuner can do these.

Just put on the holset, big injectors and bleed the boost line to ecu. Test and open the bleed so that smoke is gone boost is still in specs of the turbo (not more than 1,5 bar). You can check that EMP is under 2,5 bar.

If there are limp modes too often or you want it to work perfectly, contact a chip tuner that can do MAP based smoke limiter instead of the OEM MAF limiter.
This means that fueling is controlled by the signal from MAP sensor i.e. boost. The more boost the more fuel and no smoke if limiter map is correctly done.
Then you can adjust the maximum power just by adjusting boost (from electronic or mechanic boost controller).

morriss · Apr 3, 2009

Thanks TDIFREAK...I think ive got it? so fit Bigger Turbo fit bigger injectors! etc etc......the current turbo boosts at 9-12psi...is the ecu calibrated to this and will the actuator opening pressures currently run by the ecu be enough for the new turbo/actuator?

appreciate your help

mojogoes · Apr 3, 2009

It will probably give slow response with big turbo and oe tuning..........but then again putting in the lager nozzles should help with this in a big way.

morriss · Apr 3, 2009

ok the injectors i have sourced are from a volvo v70 tdi...which are = to bosio 502s (so i have been told)..im hopeing these will be big enough...had a nice package from Germany today my AHY manifold!!!!!!!

vindaloo · Apr 3, 2009

mojogoes said:
...lager...

How will going bio help him?

mojogoes · Apr 3, 2009

morriss · Apr 5, 2009

Bleeding the boost signal to the ecu how do i do that? is there a special device if so where can i get one!

mojogoes · Apr 5, 2009

Its a bleed valve that you fit onto the ecu/map sensor line about 4/5" from the ecu , it works better if a orifice/restrictor is also used before the valve and then you need to adjust it so when you increase the boost usually with a mechanical boost controller, the ecu only see's around 1bar of boost whan infact it is over this amount.

morriss · Apr 5, 2009

Ok I think im finally getting this....

Bleed valve before ECU on MAP line to fool ECU...and Manual Boost controller to increase Boost!.....

So basically with the larger Volvo injectors i will be fitting i need to increase the boost until little or no smoke?

Does the Holset wastgate actuator have a different opening pressure to my current K14....are the internals of the actautors different?

Sorry if i seem to be going around in circles but this is all new to me and im learning as i go.....

If I was to fit the Volvo injectors.....the fit the holset turbo conect it all up to the current N75 valve etc without bleeding the MAP signal what would happen?

TDIfreak · Apr 5, 2009

Holset propably has stiffer wastegate spring and it opens at 1...1.5 bar.
So you might only need the ECU line bleed to not go limp mode.

Even if the wastegate opens at lower pressure bleeding the ECU line is the only thing needed to get more boost.

If you don't bleed and the wastegate is stiff it will go to limp mode.

mojogoes · Apr 5, 2009

Yes TDIfreak!! good point........it all depends on how much your turbo can boost too i.e 18psi and if you want to live on the edge 20psi but note that the oe turbo won't live as long at 20psi +.........just make sure that the w/g actuator spring is good for 1.2bar and then if you can just set you map bleed to 1bar , i do this with a mountain bike shock pump that has a nice gauge on it (300psi

) i also set my w/g in the same way.

morriss · Apr 5, 2009

OK...so to bleed ECU line i need a bleed valve how do I bleed it....?

Is it a case of opening valve a bit at a time or as mentioned using a shock pump to measure bleed ?

If i need to measure the bleed valve how much pressure am i looking for....

mojogoes · Apr 5, 2009

Here you go.......http://forums.tdiclub.com/showthread.php?t=13733&highlight=a3+map+bleed+fuel+cut+defender

morriss · Apr 5, 2009

Thanks Mojogoes its starting to make sense! L.O.L...do you know of any good performance centres tuners in the south west of england?

mojogoes · Apr 5, 2009

Its a drive but you could try these guys......http://raceshack.co.uk/content/view/12/26/

Holset turbo controlled with N75 and ECU 2.5tdi

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