Audi A4R4 450HP CBEA (CR) Build

TDIMeister said:

Let's consider the option of notching the block for larger valves for a moment anyway. Since the valves are completely vertical, the notch will have to be as deep as the maximum lift. How much depth do we have from the deck surface to the top ring at TDC? If it will be less that what we envision for valve lift, I will shut up. If is not, let's do it.

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I am open to this concept..lets weigh it out.

dvst8r said:

Are you going to be O-ringing the head?

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I was going to try OEM gasket and ARP2000 studs. I think this head is stiffer than the PD head, which is stiffer than the VE head. So with some luck, we will b eok. If not, we will no the limit. I will monitor coolant pressure during tunning process. If it starts to pressurize at 350HP, for a number, then we will try somthing else. However, we are being carefull to limit PCP, and quit honestly, will probably have lower PCP than some other much lower HP builds in this club.

TDIsyncro said:

Top of piston to top ring is .475". If we assume .5mm (.020") protrusion above top of deck, that leaves .455" from deck to first ring. However, the OEM valves on this head have o protrusion, so I guess what we actually have depends a but on where the new ones will be sitting. Certainly .455" seems in the right ball park for lift. It will be a balancing act between valve dia and lift.

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SWEEEEET!!! I can do some calculations/evaluations to balance valve lift and diameter based on proper flow bench data that become available and I'll also figure them into my simulations going forward.

yeah, I keep a piston on the desk beside my mouse. How sad is that! lol

what about the impact of increased squish volume due the block notching?

Good point Rub.....

A necessary compromise.

TDIsyncro said:

yeah, I keep a piston on the desk beside my mouse. How cool is that! lol

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Fixed it for you

Farfromovin said:

Fixed it for you

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^^^^ +1

I think the Stellite is supposed to be ground, because of the hardness.

Thats, a good idea on keeping the flapper for the fill valves and controlling them for the street use! good bottom end torque for the street..


Excellent ideas! great build up..I have learned quite a bit already and trying to keep up..

Mach1 said:

I think the Stellite is supposed to be ground, because of the hardness.

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not if you have a serdi and real good cutters.
when i cut stellite vavles(gm) i have to dress my stone every 3 vavles min.good tough material but in this day and age,not needed.

I posted the HP/TQ sim on page one. I will duplicate here too.

This is one of the more recent sims I have from Dave. You can see that torque rises very quickly, even compared to a small single turbo. This is a result of optimization on turbo selection, and vanes position control and a few other tricks. You will also note we are clipping the torque at around 650n-m (480ft-lb). We are holding this torque flat from 2500 to 3500 rpm. If the cyclinder head breathes better than predicted, we may be able to hold this torque flat higher up in RPM. There are several good reasons to not allow torque to climb above this level. One is torque is directly related to BMEP & PCP. We are sitting about as high as one would want to reasonably go. For an R4 2.0litre engine, you simlpy can not get more torque without getting into a dangerous zone. Thats not to say it cant be tried, but why? Even with my Audi configuration, 480ft-lbs is a lot of torque to put down.
The other thing to note, is that this sim is based on lamba range of 1.2-1.3, and the BHP is shown to peak at around 405HP. This is a very clean smoke free HP! 450HP is reachable by adjusting the lamba down a little bit, and still in mainly smoke free power generation. This makes some of the big 6+ litre trucks putting down 400 smoke filled HP look pretty sad, that includes my own Cummins 5.9, which will get a custom VNT turbo when this project is done.

It requires a big turbo set-up to move enough air mass to produce 400+hp in TDI engine. That is why I have questioned a few posts in the past where the turbos are significantly smaller. It just doesn't work that way. The LP turbo has to be big to move ambient air mass into the system and boost to first pressure ratio. The HP turbo takes this dense compressed air, and compresses it even further. Perhaps Dave can comment on roughly how much % of work each turbo does. Its a bit counter intuitive, because the small turbo does a substantial amount of the work. One must remember this happens because the air mass is much denser at the second stage of compressing, so it fits the HP compressor and is further compressed.


This is a pic of the GTA3776V next to a PD OEM turbo. This turbo is a good 50lbs. Supporting it will be interesting.



This is a pic of the ported shroud/inlet..kinda big, yes?

Somehow I thought that the GT37V would have a dual-entry turbine. Wonder why I thought that...

You could get away with using somewhat smaller turbos if they're arranged in parallel, but then it won't be a "compound" (gawd, I hate that term) that everyone seems to be doing. Actually, beyond what I've already posted, I can't comment on the share of work done by each turbo -- proprietary. But as I've said before, there's enough information already given out for someone to figure it out... so here it is again for brevity.

what rpm approx is most of the work transferred to the LP turbo?

Isn't there enough exhaust energy for the HP to keep it "compound"
till the end of the rpm range?
I guess the dots are 1500 to 5500 rpm with 500 rpm steps.
So from 4000 rpm it will switch completly to LP?
That means it run 2.5/2.6 bar boost @ max hp @ 5500 rpm.
With 90 % ve and 17:1 lamda i need a some more boost for that hp what i calculate.
So i do something wrong i guess..
Max boost will be about 2.8/2.9 bar in midrange?

What will be the PCP max? 250 bar?

Love this project!

Johan

TDIMeister said:

Somehow I thought that the GT37V would have a dual-entry turbine. Wonder why I thought that...

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That's gt3782v. Gt3776v is single.

Interested in a trade (at least on the turbine side), Shadow? A twin-entry turbine is not optimal for a 5-cylinder anyway.

TDIMeister said:

Interested in a trade (at least on the turbine side), Shadow? A twin-entry turbine is not optimal for a 5-cylinder anyway.

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No benefit there as it's just a twin entry look alike. Twin entry to the housing, but actually single to the wheel...

I have never seen a true twin entry VNT or even heard of one. I bet keeping pulses separate has much less impact than variable A/r and this seems obvious when VNT is used with gasoline engine.

Are you planning on using any of the emissions system from the 2.0l common rail system? Eg the platinum cat? From what I have read your not using a stand alone fuel management system so how do you plan on fooling the emission sensors?

turbo johan said:

Isn't there enough exhaust energy for the HP to keep it "compound"
till the end of the rpm range?

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Yes, there is, but EMP would rise because the system is choked flowing through the HP turbine bottleneck.

That means it run 2.5/2.6 bar boost @ max hp @ 5500 rpm.
With 90 % ve and 17:1 lamda i need a some more boost for that hp what i calculate.
So i do something wrong i guess..
Max boost will be about 2.8/2.9 bar in midrange?

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My calculations fully support my target HP. Pics to follow in a future post that will back up all the numbers used below, which reflected the assumption of an 8V head with VE/PD injection technology and 400 HP. With a 16V CR and a little extra boost, I should be able to reach 450 HP easily:
VE: 91%
Boost: 3.5 bar absolute
Fuel LHV: 42.5 MJ/kg
BSFC @ rated power: 222 g/kWh -- incidently, this is the same as that achieved by the 1997 VW Motorsport R-TDI at rated power and corresponds to a brake thermal efficiency (BTE) of 38.1%
Lambda: 1.2 (AFR=17.5)
Gas constant of Air "R": 287 J/kgK
Inlet air temperature: 313 K

BMEP = BTE * VE * LHV * BOOST / ( AFR * R * T )
= 32.8 bar

BRAKE POWER = 0.5 * BMEP * RPM * DISPLACEMENT / 60
= 300.4 kW = 403 HP

What will be the PCP max? 250 bar?

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Yes, and achieved when a CR of 15:1 is used with the above numbers. This is the maximum figure at all operating points. At max power, PCP is "only" 230 bar. With a CR of 16:1, PCP comes under 250 bar at max power but peaks at 265 bar from 4500 - 5000 RPM.

So with 3bar absolute I would be able to push 340hp in a 8v 2.0l tdi with a good head.. not too far out of reach with a 2260vk, EMP will be somewhere around 3 bar at that condition (this is based on my own experince with 800° EGT and -0.1 bar due airfilter restriction).. might even be less if EGT is a little higher, also vane postion at that rpm is around 70% of max open so that will be quite ok for turbine efficiency but probaly on the right hand side of the chokeline on the comp map..

Dave you might have to have acces to 2260vk compressormap?

I have posted a 60mm, 50 trim, 0.51 A/R map before. Search with keyword "C226". It won't support the mass flow rate needed for 340 HP.

I have that map yes.. on the map it won't, in reality if you say 2bar is enough at 5500rpm it will be very close.. alotough I don't know if 90% VE is possible with emp 1 bar over boost..

TDIMeister said:

Yes, there is, but EMP would rise because the system is choked flowing through the HP turbine bottleneck.
My calculations fully support my target HP. Pics to follow in a future post that will back up all the numbers used below, which reflected the assumption of an 8V head with VE/PD injection technology and 400 HP. With a 16V CR and a little extra boost, I should be able to reach 450 HP easily:
VE: 91%
Boost: 3.5 bar absolute
Fuel LHV: 42.5 MJ/kg
BSFC @ rated power: 222 g/kWh -- incidently, this is the same as that achieved by the 1997 VW Motorsport R-TDI at rated power and corresponds to a brake thermal efficiency (BTE) of 38.1%
Lambda: 1.2 (AFR=17.5)
Gas constant of Air "R": 287 J/kgK
Inlet air temperature: 313 K

BMEP = BTE * VE * LHV * BOOST / ( AFR * R * T )
= 32.8 bar

BRAKE POWER = 0.5 * BMEP * RPM * DISPLACEMENT / 60
= 300.4 kW = 403 HP

Yes, and achieved when a CR of 15:1 is used with the above numbers. This is the maximum figure at all operating points. At max power, PCP is "only" 230 bar. With a CR of 16:1, PCP comes under 250 bar at max power but peaks at 265 bar from 4500 - 5000 RPM.

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You are right, i calculated a bit to fast..
Really nice PCP for such power output.
Almost going to petrol CR

http://www.not2fast.com/turbo/gloss...21&SFC=0.375&AFR=17.5&maxInjectorDutyCycle=85

How big WG do you need to bypass all the gasses around the HP turbo?
50 mm big enough?

Really interesting stuff this!

Johan

TDIMeister said:

Yes, and achieved when a CR of 15:1 is used with the above numbers. This is the maximum figure at all operating points. At max power, PCP is "only" 230 bar. With a CR of 16:1, PCP comes under 250 bar at max power but peaks at 265 bar from 4500 - 5000 RPM.

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What kind of pistons you re gonna use? i heard, that aluminium pistons dont take much more than 200bar. are there any forged steel pistons available? I read about mahle is developing them to go up to 250 bar PCP.
regards

195bar PCP comes from OEM already, so i dont think they would break at 200bar.
If you set SOI 4 or 5 degrees earlier, combined with higher IQ from bigger nozzles, I think you are way out of 200bar, and there are several engines driving around like this. (Mine included)

Regards, Alex

turbo johan said:

How big WG do you need to bypass all the gasses around the HP turbo?
50 mm big enough?

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I'm going to use Synapse 50mm with my build, but Meister has very different approach for controlling those turbos at high rev range looking from his graphs. I bet he needs something different.

I needed only ~1,25bar to make 310bhp @4000rpm (and later with bigger MAF housing @4900rpm) on my 2,46L 5cyl. Pump gas, no NOS. Some smoke, but not that bad (that's relative, I know ). AFR=16-16,5? That really surprised me.

I'm using a 38 mm WG on my compound project.
But i thinking maybe it would be a bit small if the rest should go through the 40 mm exducer VNTturbine...
But i'll settle with a bit less hp

Stock pistons can handle a bit more than 200 bar PCP.
I think there are a lot of people driving around with high tq and spiking turbo which will give probleby on stock cr 250+ bar PCP....

Johan

glitdi said:

Are you planning on using any of the emissions system from the 2.0l common rail system? Eg the platinum cat? From what I have read your not using a stand alone fuel management system so how do you plan on fooling the emission sensors?

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There will be no emmissions, however, Lamba is at 1.2 under full power, so this is by no meams a dirty build. It is probably cleaner than a lot of power builds at 1/3 this HP level. We are not using the EDC17 ECU that came with the 2009 CR engine, so the emmisions requirements are simply not there.