Vw T4 Acv ........2.5tdi

Hi all

sorry to start a new thread...

anyway the story so far

ACV 2.5tdi
2.5" exhaust
2.5" turbo down pipe unretrictive elbow
hybrid turbo much larger comp wheel housing turbine wheel housing
volvo V70 tdi injectors and nozzles
egr power pipe large front mount ic
minor tweak to map

the v70 injectors gave me 148.9bhp with exhaust and FMIC
I then had the comp wheel ground out and a slightly bigger comp wheel
a remap (not sure how good) and got 163 bhp with smoke....


then i fitted a 2.5" turbo downpipe which gave 1bhp

and now turbo has been upgrade with a much bigger comp housing wheel turbine wheel etc.....

and now getting 170bhp..... with smoke..

now since the new turbo fitted smoke seems worse....

170bhp acheived at 16.6psi of boost....

with actuator rod shortend 26psi of boost avheived but bhp less 165bhp??????

I guess i need a new remap to take advantage of new hardware but can anyone think of any other resrictions.....

Also does anyone know of a good TDI remapper in the Uk?????

morriss said:

with actuator rod shortend 26psi of boost avheived but bhp less 165bhp??????

Click to expand...

Check your EMP and you understand why...

ah I see

I guess its all down to the MAP now

We need to know the specs of the turbo.
Going from 16 to 26 psi is a big step. Try something in between. And stiffening the actuator is not the right way. Bleeding is better and remapping the best.

Do you have the part number for V70 injectors. Last models used weird nozzles.

slow-moe said:

Do you have the part number for V70 injectors. Last models used weird nozzles.

Click to expand...

Last models are with totally different engine (-01->, no VAG relationship, 2.4L, 20v, CR, got 251hp,600Nm out of such on my wife's Volvo S60), but all Volvo 2.5TDI nozzles are suitable as it is VAG engine.

Yes, I know. But if you look at the injector from V70 with part number 074130203A (needle lift) the nozzles have bosch number DSLA93P838. All other AEL/D5252T based Audi/Volvo engines have DSLA150P502.
Is this the old engine with wastegated K14 or newer one with GT2052V?

Both seem to be for VAG engine according to a quick (1 minute) Google search. But why to use them as you can go straight to Bosio R520 (5-hole) which is the way to go with 11mm pump? Are they cheeper or something?

Is the ACV exhaust manifold a limiting factor in tuning what BHP is it good for??

Also Shadow Mika the guy that does your mapping does he have a website of a contact address.... I fear a trip to see him might be my only option as there isnt anyone i can find in the uk that can live remap my T4....

Feel i have enough hardware now to get my T4 to 200bhp just need the mapping sorted.....

TDIfreak said:

We need to know the specs of the turbo.
Going from 16 to 26 psi is a big step. Try something in between. And stiffening the actuator is not the right way. Bleeding is better and remapping the best.

Click to expand...

when you talk about bleeding are you refering to bleedin the MAP line of the Actuator???

Bleeding the MAP line.
I think you should measure the turbo before reserving tickets to the ferry...

Your emp (exhaust manifold pressure) sounds like its too high.Ideally you want it to be a little lower than boost but thats hard to acheive on low boost ie below 20 psi, maybe 2 to 4 psi higher than boost would be achievable.Then you will need to look at a different map sensor the std acv seems to be a bit hit an miss above 1.2 bar.

tdi rs said:

Your emp (exhaust manifold pressure) sounds like its too high.Ideally you want it to be a little lower than boost but thats hard to acheive on low boost ie below 20 psi, maybe 2 to 4 psi higher than boost would be achievable.Then you will need to look at a different map sensor the std acv seems to be a bit hit an miss above 1.2 bar.

Click to expand...

hi im using a turbo down pipe supplied by you many thanks its a quality bit of kit

MAP sensor is on the list of things to sort....was hoping to get away with bleeding the MAP to stop limp mode im not sure my current map is up to much the injection duration etc my well be off the mark.....

what are the comomn causes of high EMPs and what can i do to correct them........???

morriss said:

Is the ACV exhaust manifold a limiting factor in tuning what BHP is it good for??

Also Shadow Mika the guy that does your mapping does he have a website of a contact address.... I fear a trip to see him might be my only option as there isnt anyone i can find in the uk that can live remap my T4....

Feel i have enough hardware now to get my T4 to 200bhp just need the mapping sorted.....

Click to expand...

I started to use custom made ex mani for some 8 years ago (turbo didn't fit between the engine and the firewall + it helps maintenance), so I really have no idea how restrictive the original one is. Usually it is the turbine, not ex mani, to blame.

Maybe a forum member called rake can help you out with your mapping. He has been fiddling with T4 for some years already in the UK and we have discussed about more serious T4 tuning already. Of course my man Mika can help you out, but that's a long trip over here...

Mika has a website, but only in Finnish... http://www.turbotec.com

Here's something nice for T5 owners (96kW version) from his site:


originally 101kW/137 hp - 335 Nm

with DPF delete 143kW/194 hp - 461 Nm

If you want it can be pushed over 200hp with a bit beefier program.

Thanks Shadow Rake and I are already acquainted.....


You managed 186bhp with stock injectors and uprated stock Turbo do you recall how?

The turbine side of the hybrid turbo was made bigger i only want to acheive 200bhp but i fear the restriction is the EMP if so Im at a loss as to how to reduce the EMP.......... how much affect does the remap have on EMPs...


I have some Bosio Race 520s to try also do you think a significant gain will be had????

morriss said:

Thanks Shadow Rake and I are already acquainted.....

You managed 186bhp with stock injectors and uprated stock Turbo do you recall how?

Click to expand...

If you mean how that turbo was uprated, I have no idea anymore. At that time I didn't knew anything about hybrid turbos or diesel upgrade. I just sent my turbo to a decent turbo shop and got it done.

And don't get fixated to 186hp as that is just one dyno reading. I can't back it up with anything + I don't have that plot anymore. It was done in the same dyno I have been using ever since, but maybe it reads high compared to the dyno you are using. Dyno is just a tool for setupping and real performance figures are what really count.

Thanks shadow....

well im pretty much where you were 8 years ago know very little but learning as i go.......

I will pop in the Race520s and see what happens im at 170 currently so might add a few extra horse

TDIfreak said:

We need to know the specs of the turbo.
Going from 16 to 26 psi is a big step. Try something in between. And stiffening the actuator is not the right way. Bleeding is better and remapping the best.

Click to expand...

Turbo spec

Uprated thrust
Turbine Wheel Ind 51.5mm Ex 41mm
Compressor Ind 42mm Ex 61mm

The turbine housing is the standard item machined out.
The compressor cover is a larger cover machined to suit

Ok the wheels support 200hp and more but the standard item turbine housing will cause high EMP and propably melting the pistons if you now put R520 and push it to top speed.

TDIfreak said:

Ok the wheels support 200hp and more but the standard item turbine housing will cause high EMP and propably melting the pistons if you now put R520 and push it to top speed.

Click to expand...

The turbine housing has been machined out to allow for bigger turbine wheel etc.......

is it best not to use R520 and stick with Volvo spec nozzles and remap??

And with this set up will i reach 200bhp

Of course it's machined to the bigger turbine wheel.
But the throat of the housing is too small to flow enough for 200 hp.

I'd say stick with the Volvo injectors.
Try to get the max boost so that EMP is not more than 1 bar over boost at peak hp.
And then tune fueling to achieve most hp without too much smoke.

so it needs to be bigger to flow 200bhp will machining it out as much as possiable make a difference??


Ok and another silly question the EGR port on the exhaust manifold this is blanked off and i have an adapter there to measure EMPs......... Is it possable to reduce EMPs by fitting some type of valve there....... is there such a thing???

If you let some of the exhaust gas out of the EGR port to reduce EMP the turbine will get less exhaust thus reducing the speed of compressor and reducing boost pressure. Not good.

With too small turbine housing you create bottleneck after the engine into which it's easy to create boost against and get the feeling that everything is okay but actually you're not flowing much air.

With larger turbine housing exhaust starts to flow and the engine can create some real power.

Machining the standard housing to 200hp is not practically possible.

I've dynoed my D5252T, 196 HP @ ~3 300 RPM / 457 NM @ ~2 600 RPM in the engine, not the wheels with KCR plug-and-play box, modified ECU box, 1,6 maximum bar boost pressure, big FMIC and 3" exhaust.
I don't dare to see what EMP I had at that moment because the ammount of fuel it got was no short supply but it's obvious that the original KKK14 turbo is too small, especially at higher speeds and RPM.

(You can take a look at this Swedish site for pic and more info:
http://www.garaget.org/?car=88943 )

Really nice Simon!