Hybrid K04 Turbo Discussion

[Mitchy]

Carl...

In 6th gear, so lots of measurements due to the increased time in gear, but will give you an idea of the whole turbo range. Well as far as i managed lol, 6th gear at these kind of revs is well, you know

3760 = 2490/2540 = 95.7%
3880 = 2480/2540 = 92.5%
4040 = 2490/2540 = 89.4%
4200 = 2480/2540 = 85.9%
4320 = 2470/2540 = 81.6%
4440 = 2450/2540 = 78.8%

(Turbo producing over 1.55bar boost for 700rpm. That is 1.8bar falling to 1.55bar in that time according to boost gauge. Obviously cant get more accurate results as MAP sensor limited)

4520 = 2430/2490 = 77.6%
4640 = 2410/2410 = 78%
4720 = 2420/2420 = 78.4%
4840 = 2410/2410 = 79.2%
4920 = 2410/2410 = 80%
5080 = 2390/2390 = 86.7%
5160 = 2390/2390 = 92.5%

As you can see upto 5160rpm actual is meeting requested all the way, with ease. Wastegate not maxxed. Now the turbo begins struggling to meet requested and wastegate is working harder to try and achieve this....

5200 = 2390/2300 = 94.9%
5280 = 2380/2310 = 94.1%
5320 = 2360/2310 = 92.2%
5400 = 2350/2260 = 93.7%
5440 = 2360/2250 = 98%
5480 = 2360/2260 = 100%
5520 = 2340/2220 = 91%
5600 = 2330/2220 = 95.3%
5720 = 2280/2180 = 100%
5800 = 2250/2210 = 100%
5840 = 2250/2190 = 95.7%
5920 = 2250/2110 = 100%
6020 = 2220/2150 = 98.7%

OAT was 11c and IAT max when i come off the throttle above at 6020 rpm was 40c, even with FMIC

On 4th gear runs, ive never seen it above 28c

And then thats as far as i went as i was going pretty quick at this time and everything was getting hot,hot,hot! Oil temp now around at 150c so had to back off for a while.

Gives you an indication of what the turbo and wastegate are doing to achieve boost. Upto 5160rpm, the turbo is clearly not maxxed and has more left to give. However after this, it starts struggling even with nearly maxxing wastegate to achieve requested values.

 

[Mitchy]

However i done the same thing in 4th gear, all the way upto 6800rpm and wastegate % never went above 88%

 

[Mitchy]

Wilko/Bill if your reading...What effects occur when adjusting the actuator?

The turbo's were standard K04's until they went for the hybrid treatment and had never been adjusted, meaning they are set exactly the same as a bog standard K04.

What happens if you tighten down too much? Turbo damage?

 

[m0rk]

limp mode, the delivered boost will be more than requested by x% and it'll revert to 5psi

 

[Mitchy]

So it will give increased boost pressure? Can you explain why Mark?

My deviation map is set at 250mbar so i would think that it shouldn't go into limp.

May be worth doing, especially on Scotty's car, as he can adjust requested values with SPS

 

[m0rk]

it just shuts the actuator more than it thinks it has thus more boost

so the ECu says '80% w/gate duty' but in fact the w/g is 99% (for instance)

 

[Wilko]

I would surgest that you all get under your cars and measure wastegate rod length. If they're all the same, buy a new n75 and check yours are OK. Tey do age/get full of dirt.

 

[Scotty_b]

Wastegate rod? Do yo unot mean actuator bar or am i getting the wrong end of the stick?

So what do you want me to set to on sps (old version) and what logs do we need?

It will ahve to be after i get my leak sorted as ive been hitting 28 psi the last few days!

 

[Mitchy]

Scotty if you look down from it from above, you can actually get access to the actuator rod. There's no need to do it from below.

You will need 2 10mm spanners to adjust.

Measure the distance accurately before you start, so you know your starting point. Measure from where the left hand nut is to the very end of the rod. (Its probably somewhere in the region of 16-18mm) You need to lengthen this distance to put more pre load on the wastegate.

Slacken off the right hand nut, and slacken it back a couple of threads. Then tighten up the left hand nut to where the right hand nut is located and then tighten both nuts together against each other.

Your measurement should have got larger and you will have put more tension on actuator.

 

[Feel]

Surely they'd be better getting the requested boost turned up rather than fiddling with the actuator?

I though most maps ran 95% duty cycle, so at 80% they've got some left to go?

Scotty - log 115 and 118, then whack it up to HB9, check timing, then log 115 and 118 again. I would imagine that with your FMIC you won't need to worry about IAT, but twe'll see tht in the logs.

 

[Mitchy]

This is a picture of actuator rod.... (not from our turbo's but its exactly the same)

You need to push the left hand nut further to the right, to give more pre load to the wastegate. Slacken off right hand nut, and wind down left.

The measurements are from the edge of the left hand nut to the very end of the rod. (Like i said should be in region of 17mm at moment)

 

[Mitchy]

Surely they'd be better getting the requested boost turned up rather than fiddling with the actuator?

I though most maps ran 95% duty cycle, so at 80% they've got some left to go?
I would imagine that with your FMIC you won't need to worry about IAT, but twe'll see tht in the logs.

Requested boost will turn up with SPS, actual will/should go up with a tweak of the rod.

My IAT were only high because my logs were done in 6th gear, and things were getting very hot. I have the forge FMIC aswell

 

[Feel]

Actual will go up to try and meet requested (after tweaking with SPS) until duty cycle at high revs hits 95%-odd.

I wasn't talking about your IAT, I meant that Scotty needn't worry too much about IAT for a few logs.

On those logs you've posted above, I take it the percentage is calculated? Better to log 118 and measure actual duty cycle, surely?

 

[Scotty_b]

My Actuator will be set different to all of yours as im running an uprated forge version.

Ok im booking the car into VAG Tech in the next week or so so soon as shes out i will start logging

 

[YerMother]

Why you go with the forge actuator Scotty When i spoke to forge ages ago they said it's pointless, the only reason they sell them is to replace the standard if they fail, because if they do you have to buy a whole new unit!

Guys i wouldn't be playing with the wastegate actuator too much, part throttle drivability will be awful as it will be boosting too much!

You noticed any difference mitchy?

 

[YerMother]

Scotty those logs look promising! Still plenty left there! Doesn't look like you have a boost leak with it only reading 63% wastegate actuator duty!

 

[wild willy]

Good logs Mitchy. Surprising to see that different gears result in differing duty cycles.
Scotty, its interesting that you have an uprated actuator, how did vagtech determine the settings of the actuator. When you've found the boost leak it may well be that your ready to run on uprated boost settings.

 

[Mitchy]

Why you go with the forge actuator Scotty When i spoke to forge ages ago they said it's pointless, the only reason they sell them is to replace the standard if they fail, because if they do you have to buy a whole new unit!

Guys i wouldn't be playing with the wastegate actuator too much, part throttle drivability will be awful as it will be boosting too much!

You noticed any difference mitchy?

No real noticable difference with a 1mm adjustment, might give it 1 more tweak to 2mm, and if there's still no noticeable difference ill put it back to the way it was standard.


I have had part throttle surging, but i think thats down to my N75 being on its way out. However saying that, its only happened once. It seems to be fine now

Im sure i read that the effects of tightening the actuator will slow down the spooling time as a negative and increase the boost pressure up top as a positive. However in my case that is exactly what i need as the spool is very quick low down and i dont mind making it spool any slower.

I know what to expect if i tighten down the actuator too much, boost creep. Thats easy to spot so ill know ive gone too far, boost gauge will let me know about that.

Sie it was Jacob who has suggested actuator, he says it works wonders on the 2.7 K04 S4 turbo's

 

[Scotty_b]

The Forge actuator uses stronger springs so holds more PSI before it lets go. Im not sure how VAG Tech set it up, but i will ask them next time i speak to them.

http://www.forgemotorsport.co.uk/content.asp?inc=product&cat=1305MISC&product=FMACVAG04
Cnat find mine but as stated in the post it says youcan specify the uprated springs

 

[ibizacupra]

boost creep is when wastegate cannot flow enough so control of boost is not possible..
I had this on my previous less ported wastegate on my current setup.
5krpm open wastegate and it still spooled 2.2bar and beyond!