Hybrid K04 Turbo Discussion

[YerMother]

Basically to force the exhaust gases through the turbine housing and pass the turbine blades requires energy. This energy is supplied by the piston forcing the gases out of the cylinder on its exhuast stroke reducing the power at the crank.

So the power at he crank is the positive power from the power stroke - the power required to force the gases through t the turbo

The smaller the pumping loss the more hp you have at the crank, so a larger turbine/housing reduces the back pressure at the turbine side reducing the pumping losses because the gases flow more easily through it!

 

[Saul]

larger turbo opens the bottle neck in the flow in laymans terms

 

[DPJ]

Thank you. ('power at the crack' had me for a minute...)

 

[ibizacupra]

Bill, why do you think CC has set Mitchys boost levels so low at the red line considering its an uprated hybrid. It has no problem hitting its requested.

did'nt he say when more was requested it was'nt being met?

 

[ibizacupra]

Bill. Where do I start?
At the same manifold boost pressure and the same rpm, you will have the same volume of air going into the engine.
Where the turbo comes in is that at a turbo opperating at higher efficiency on the compresser map will heat the volume of air less, so it will have higher mass (slightly). At 6500rpm and 21psi of boost, the difference between a compresser running at 70% efficiency and 78% efficiency is a difference between 131C and 142C compresser outlet temp. This equals about a 2.7% difference in mass flow (note mas not volume)

Now this doesn't take into account the density recovery of the intercooler. A 70% thermally efficient intercooler with a 20C ambient condition will drop these outlet temps to 57C and 53C, so post intercooler the density differences will be 1.3%. This doesn't take into account the heat sink of the mass of the intercooler either, so differences would be even less untill the IC is heat soaked.

So at a fixed manifold pressure the difference in mass flow between a super efficient (not necessarily bigger) turbo and a crap one is about 1-1.5% mass flow rate into the engine, so bugger all.

The real benefit of the larger turbo is reduced pumping losses on the turbine side and therefore more power at the crack from the same airflow rate through the engine.

Look at any logs of airflow at 21psi from guys running 3071's or 2871's, or 28rs, or IHI, all of which will hold 21psi at 7000 on a small port head and they all flow 240-250g/s. They will all make similar peak power (within 10%) as well. (at the same maintained manifold boost pressure.)


The 3071 could hold 30psi, and thats where the power gain from that turbo will come from.

I dont think we're disagreeing with each other john. :0


clipped from my earlier post
{same boost more mass airflow - bigger units sustain their boost in the rev range hence more bhp which is function on rpm and torque)}

holding 32psi to 8200rpm on my own... (more if I would let it)
big arsed turbine, largish compressor

I do recall a post being made that these figures would not be possible on smallport due to port size restrictions, but there do seem to be folk over on vortex claiming numbers above that.
I am interested to see how the GT35'd octy performs on its smallport head and stock sized t'body. I know in total airflow terms, from same boost levels, more airflow=30bhp/20lbft more for me when I changed to 007mani with the 75mm t'body.

total airflow is whats contributing to power output, boost is the motive power to achieve the airflow. removing restrictions, which are after all all relative to the airflow being flown (big turbo, little turbo), are what help give the power levels.

 

[Mitchy]

Yes on jabbas map, requested was not being met by quite a considerable difference.

2450 requested at 6500, 2100 produced.

 

[Wilko]

Thank you. ('power at the crack' had me for a minute...)

Look I'm an engineer, not a bloody linguist.

Looks like people are starting to understand though.

 

[DPJ]

Look I'm an engineer, not a bloody linguist.

Looks like people are starting to understand though.

Cunning linguist? John, I genuinely misread you - I should have thought harder, sorry

 

[Wilko]

Bill
At 32 psi at 8200rpm at high 90's VE you're at 50-53lb/min of airflow, which I though was where your compresser maxed out.

Now I reckon (from my own measurements) that the smallport on standard cams, manifold etc is running high 90's% VE upto just ove 6000rpm. By 7500rpm, the VE is down below 85%.

On that basis, said Octy will need to run over 40psi to get similar flows to you at 32psi.

Look at a gt35 comp map . Pressure ratios above 3.3 don't even appear on the map and 40psi would be a pressure ratio of>3.75. At the flow rates you're seeing, the map doesn't go above a pressure ratio of more than 2.9.

To even run 30psi before 4700rpm would put the comp the wrong side of the surge line and chances are it wouldn't spool until then.

Totaly unsuitable turbo for that engine. Big port with cams would be different, but at 30psi on a big port at 8000rpm it'd be right on the edge of the map.

That's why it's not going to work! Though a little etch a sketch on the dyno plot will sort it out.

 

[Scotty_b]

I have now set my revo to HB8 and T7 now so i will get some logs as soon as i get a dry day and time to swap my tyres over.

So have we been mislead in what this turbo can do?
We have duff versions?
We nee dto geta decent map on it?
Inital redaings on sies car are over kill?

Mitchy how much is this JBS 05 turbo tho?

 

[Mitchy]

I have now set my revo to HB8 and T7 now so i will get some logs as soon as i get a dry day and time to swap my tyres over.

So have we been mislead in what this turbo can do?
We have duff versions?
We nee dto geta decent map on it?
Inital redaings on sies car are over kill?

Mitchy how much is this JBS 05 turbo tho?

Yes almost definitely. It is flowing better than standard K04 so not a complete waste, its just not flowing as well as we hoped for. Well mines isn't.
Sie has a 023 version, we have 020 versions. Jacob was adamant they were 100% the same.
Ive had Jabba/CC map the turbo, its not the mapping
I think so, i would like to see them results being achieved at JBS for ''proper fly figures''

If you supply JBS with a K04 turbo, its £650+vat to do the work (£765) Should only take about 3days to do. K04 turbo can be sought off ebay for £250 so it takes us upto about £900ish, near enough the same as Jacob's hybrid. For a new outright version though, i do believe the cost is about £1300.

He said its a 300bhp turbo and possibly slightly more. On JBS's dyno i do believe they are good figures
Nothing is mentioned on their website about the JBS05, it was just word of mouth that i heard about it.

Although im not so sure if its worth swapping turbos again, maybe just better sticking with the units we have got and try to get the best from them. I doubt we are far from that 300 figure in any case with these hybrid units we have.

Standard K04 max =275-280bhp
This hybrid, im sure 290-295bhp

 

[ibizacupra]

Bill
At 32 psi at 8200rpm at high 90's VE you're at 50-53lb/min of airflow, which I though was where your compresser maxed out.

Now I reckon (from my own measurements) that the smallport on standard cams, manifold etc is running high 90's% VE upto just ove 6000rpm. By 7500rpm, the VE is down below 85%.

On that basis, said Octy will need to run over 40psi to get similar flows to you at 32psi.

Look at a gt35 comp map . Pressure ratios above 3.3 don't even appear on the map and 40psi would be a pressure ratio of>3.75. At the flow rates you're seeing, the map doesn't go above a pressure ratio of more than 2.9.

To even run 30psi before 4700rpm would put the comp the wrong side of the surge line and chances are it wouldn't spool until then.

Totaly unsuitable turbo for that engine. Big port with cams would be different, but at 30psi on a big port at 8000rpm it'd be right on the edge of the map.

That's why it's not going to work! Though a little etch a sketch on the dyno plot will sort it out.

I know I have my thoughts on airflow and heads, port sizes, throttle sizes etc, and we did'nt agree but did laff about it. Time will tell what happens with it.

Largeport and revving to 9K and 550bhp+ potential tho I think.

lol @ etch a sketch gibe..

 

[wild willy]

Carl, when it was mapped by jabba the requested was quite a bit higher than the actual and the turbo couldn't make it.

They were requesting 1.4bar at 6500rpm, turbo was no where near it.

Jabba's map with the boost controller fools the deviation into not going into limp mode. Without the boost controller, if the deviation is too high the engine will go into limp mode.

With jabbas map, it was always 1 step ahead of you because of this. You could fiddle with the car, make more boost pressure and not need to adjust the requested values. On CC software you cant do this because of deviation limits set.

I need a cable that can connect to CC software so i can fiddle with a few things. My serial port cable is not working with the software, works fine with vagcom though

Ah, That explains a lot. Well fair play if you have given the turbo a decent load and it failed to meet it, I can't argue with that.

 

[wild willy]

If you supply JBS with a K04 turbo, its £650+vat to do the work (£765) Should only take about 3days to do. K04 turbo can be sought off ebay for £250 so it takes us upto about £900ish, near enough the same as Jacob's hybrid. For a new outright version though, i do believe the cost is about £1300.

He said its a 300bhp turbo and possibly slightly more. On JBS's dyno i do believe they are good figures
Nothing is mentioned on their website about the JBS05, it was just word of mouth that i heard about it.

Although im not so sure if its worth swapping turbos again, maybe just better sticking with the units we have got and try to get the best from them. I doubt we are far from that 300 figure in any case with these hybrid units we have.

Standard K04 max =275-280bhp
This hybrid, im sure 290-295bhp

I'm not sure its worth changing for those figures either. Pity we didn't know before hand.
Mitchy it would make more sense to go ihi..... turbo £450 (import), Mani £550 plus all the extras but serious power.

Jacob owes us an explaination.........

 

[J@mes]

its not looking good is it guys!


sorry but i must say... im glad i didnt take the plunge now! (no offence guys! )



but look on the bright side... it looks as if your hybrids are good for another 10 - 20 bhp more over stock k04... i mean scott deffo has a boost leak, can hear it very loud, AND its still not mapped, and he still got the same power as me on sunday! (well 1 more bhp/8lbs less!)

 

[DPJ]

Yes almost definitely. It is flowing better than standard K04 so not a complete waste, its just not flowing as well as we hoped for. Well mines isn't.
Sie has a 023 version, we have 020 versions. Jacob was adamant they were 100% the same.
Ive had Jabba/CC map the turbo, its not the mapping
I think so, i would like to see them results being achieved at JBS for ''proper fly figures''

If you supply JBS with a K04 turbo, its £650+vat to do the work (£765) Should only take about 3days to do. K04 turbo can be sought off ebay for £250 so it takes us upto about £900ish, near enough the same as Jacob's hybrid. For a new outright version though, i do believe the cost is about £1300.

He said its a 300bhp turbo and possibly slightly more. On JBS's dyno i do believe they are good figures
Nothing is mentioned on their website about the JBS05, it was just word of mouth that i heard about it.

Although im not so sure if its worth swapping turbos again, maybe just better sticking with the units we have got and try to get the best from them. I doubt we are far from that 300 figure in any case with these hybrid units we have.

Standard K04 max =275-280bhp
This hybrid, im sure 290-295bhp

I know it's not what you were looking for, but it's not bad bang for bucks at your stage of tune...............

 

[Scotty_b]

Thats cheaper than i was expecting, especially as i still have my old turbo!
But if i was only to get the same figures id rather spend the money on a remap/new mani etc.

I think we all needto get to the sam rolling road, get some figures, get all our issues sorted then bang off an email to jaccob as hes been very helpfull so far

 

[Feel]

I know I can't really talk about this, having not done it (the hybrid that is).

BUT Scotty apparently has a boost leak and Mitchy is "only" running stage 2 CC, effectively the same as Sie's but without a boost controller, yet you say it's the turbo that's at fault? Either that or there's some "funny business" to do with Awesome's rollers? Plenty of other people, with more experience than me where there that day, and they all seemed happy

I know you say that the turbo's not meeting requested and therefore it doesn't matter what requested is set at, but I would beg to differ. Well, I would wonder about it enough to try it.

I'd be doing my best to get it to work. If you get a JBS05, get it stage 3'd by CC and run it on JBS's rollers, it wouldn't surprise me if it miraculously makes more power than Jacobs on Stage 2. I would find out the specs of this JBS05, I would imagine it's very similar to the K04-23 that Turbo Dynamics do...

Ah well, whatever. It's your car(s)

P.S. S3mon's S3 was the other car that had one on, it didn't fare too well at an Audi-sport.net RR day, but I seem to remember he had some issues...

P.P.S. re: your earlier comments about Awesome's LCR's figures on their rollers - from memory it did rather well at JBS with a turbo back and before Stage 2 code

 

[ibizacupra]

it did'nt make requested boost on Jabba, it wont make requested boost on CC either (although its asking for less and close to its physical max) and its not the turbo?

log the wg duty cycle...
elminate that and blank off the actuator hose and drive it carefully up the rev range to max throttle and see what it actually manages with no control whatso ever... (carefully) - either that or theres some creepage from wastegate being blown open slightly or something.

please explain?

 

[Mitchy]

Feel, even with CC 2, i still feel it will be as good as the CC3 setup.They are still trying to achieve the best from it. (They did have car for 3 days)

I did have it jabba mapped also, so i firmly believe it is nothing to do with the mapping.

Reference awesome's rolling road, we all know they have problems with calculation of flywheel figures. I also think they are ''generous'' with wheel figures. Take your car to say 5 independant rolling roads and measure wheel/flywheel powers, i guarantee an LCR will lose 35+bhp through the transmission on all 5.
Now apply these figures to that of awesome's wheel figures and you are going beyond the maximum flow rate of the turbo (You linked us to Borg warner site where max rate is 280bhp)

Lets take average loss at 40bhp, Awesomes own LCR around 258whp. That K04 turbo is producing 298bhp Why when turbo is only rated for 280bhp? Where is it finding this extra grunt from?

Then the others, there are a couple of more ''APR stage 2 tuned'' cars on the 250whp mark, apply the same 40bhp loss and there's 290bhp, still above the threshold. Then you have the riff raff CC/Jabba/Revo stage 2 guys lower down at around the 240-245whp mark. (280-285bhp with applied 40bhp loss)

From my own evidence, wheel horsepowers measured from JBS and Jabba are about 10whp down from those measured at Awesome

I was also amazed when i was last at awesome on their rollers to find the brake being applied on coastdown?? I thought to get an ''accurate'' fly figure the wheels were to just spin until they had stopped naturally without a braking force?

People are going to be happy with generous whp readings, hence why people are happy paying their money on awesomes rollers. They know fine well they're only getting 1/2 a result with their measurement of fly figures but because they're wheel readings are good, then they're happy. My own car losing a mighty 7bhp for instance

I was surprised when Sie got the 273whp result. If it were me, i would have went straight to JBS, paid my £40 and got an indication of the fly output. Maybe Sie just aint bothered, thats upto him It wasn't Sie that sold us this turbo, he only posted his results and then we all jumped in feet first, thinking we would get the same.

I think we should have done more research but like i said before, its only a grand down the swanny (I needed a re-remap anyway to take all additional mods into account, so was not fussed about that)
To make myself feel a little better, i now have a brand new slightly better flowing turbo and my old K04 had cracks around the wastegate port, so that was on a slippery slope anyway

IHI would be the next option but its another £2000 at least even if sourcing the parts cheaply. Im not going to bother, its still plenty quick enough for our roads, it still scares me now and again so i think the hunt for bigger power is over for me. Nitrous boosts me up a bit further to safe max limit of rods anyway. If i went IHI, i'd then have a redundant £1500 nitrous system so it doesn't make sense for me to do so.

I suppose its the only way you learn, and i certainly wont be buying £950 hybrid turbo's in the future James, you jammy git You were very nearly there and pulled out right at the last minute. In hindsight i wish i had done so

At least i can laugh about it though i suppose