Golf II GTD with 1.9 AAZ engine --- EVO II

[RabbitJockey]

yes i know gasket matching on the exhaust ports is actually the removal of alot of material

[Alleslowbuged]

... some say it was a bit of rubbish, they say it has eaten 100 kg of solder,
... all what we know is, that it running again.

As promised i have make a second solder try last weekend, here is the result:




Today it was crunch time and i have regrind nearly all that solder out again:






After that i have reassemble the head and bold it down on the engine. I was not sure and i am still concerned
if that will work for a couple of hours, but up to know it seems to be sealed. I have restart the engine, refilled
cooling water and let it runnig on idle up to working temperature, without any manifold, so i could take a look
directly to the place where the hole was.

What i do not know is, what will happend due to the big amount of solder in the cooling channel when it comes
to hotter times than idle speed.

Instead of waiting for the cylinderhead cooling, i started to manufacture a new intake manifold, after i measure
the main inlet of the stock inelt manifold with 15 cm², while each port has 12 cm²?














Best Regards
Alleslowbuged 

[theman53]

Beautiful. I am sure others will say otherwise, but anytime you can make scrap run it is beautiful. Like the intake too.

[Toby]

Nice work. Shouldn't the slot be tapered, though? Did you make the turbo adapter, as well?

[Alleslowbuged]

Hi,

thanks for the nice words.

I don't think that the slot should be tapert, but it would be better if the pipe would be tapert in that area.
Pherhaps i will cut the pipe after it tis connected to the lower manifold part, but i am not sure if i shoud do
or not. I think on the other about about leting the pipe open to both sides, so that i have more options for
a later intercooler upgrade.

The turbo adapter was make by a shop special for me, but it is welded as scrap and i dont think it will be work
long time. The first attemp of the adapter was running for 8 km before it cracks on the wastegate pipe. Now they
have just rewelded the crack, but i can still see the rest of the crack from the inside, so i think it will crack again
in very short time. It is very poor if you give your money to an "expert", and than reconize he is not a expert for
his buisness at all.

I will make the next driving km (only running in the camshaft), if the port will stay sealed, without the external wastegate
and hope that the adapter will captable for taking just its own weight. Than we will see what's happen.

Best Regards





 

[RabbitJockey]

technically on a dual plenum manifold you would want the inlet there to be tapered, the further away from the inlet the smaller it gets so that equal velocity is the same the whole way across, much like how the schroll of a turbo housing gets smaller around the wheel.  but i think you can accomplish the same thing like you have said by pipe being tapered down in size the further u get from the inlet as well, much like the ducting in a house gets smaller the further it gets from the furnace in order to maintain air speed.

[Alleslowbuged]

Hi,

33



Best Regards

[BlueMule]

Alles, it looks like you have done a good job on the brazing, see, I knew you could do it! If it is not porous, it will be fine!! I guess you kind of freaked when your screwdriver penetrated the water jacket, but it happens, even to the most seasoned pro. Because of void spaces and differences in casting, you could have the same head, same year, and woot there it went. That’s why there is no guarantee when modifying or moving ports. Sometimes a head can be saved sometimes no. As far as the water jacket, usually your brazing would fill part of the void and not a large part of the passage itself. So on that account, I don’t think you will have a problem with this.
I do have a concern about you head though (cylinder head that is ). Usually while repairing a head in this manner, a large, flat steel plate, maybe 30mm or more is bolted to the head to prevent or minimize warpage. So it would be a good idea to check for flatness before installing. 

As far as your turbo adapter, since you said it is showing signs of cracking again, is sounds like the steel has failed at the molecular level due to heat and the vibration is just breaking the steel apart. If this is the case the adapter may be unrepairable. There are some things to keep in mind when building this type of adapter. First, if it is going to be structural, in other words supporting the turbo with no bracket, it really should be 13mm or more thick at the walls. In fact solid machined billet or cast would be best. Also 321 Stainless with 347 stainless wire or rod for consumable, if it is going to be multi piece welded assembly. Inconel is another option, but is very pricey. I think if you use the 321 and proper consumable, with a well thought out bracket to support the turbos’ weight, this should cure your cracking of the adapter.

Now, on to the intake. I have enclosed a link, and according to two rally guys, the dimensions of the “funnel” are correct. I don’t know because I am used to going very straight, fast and a ¼ mile at a time, but I am getting used to turning. The reason for the funnel shape is to ensure equal velocity and volume across the whole “plane” of the manifold. This design also cuts down on the curves the air has to pass through and thus cuts down on turbulence, supposedly. Anyway, Audi etc use this type of manifold for high output engines. I’ve never seen dyno specs one way or another, but it makes sense to me.

http://www.jasperintegration.com/navi.html 

Hoping you are able to finish your project shortly
BlueMule

 

[Alleslowbuged]

Hi BlueMule,

thanks for your thoughts, the last picture shows my little garage, with golf is missing, whichs means that everything is reinstalled and i have drove the first 33 km today.
Up to knaow there is now leakage and no extra pressure on the cooling system, but the engine has only seen max. 3500 rpm and max 0.6 bar boost pressure.

Regarding the intake manifold, i have carried some cfd simulation and came to the conclusion, that my first idea will not work properly. I had scheduled to use a Ø50 mm pipe as primary pipe, but this will be way to small. At my power goals the velocity in the pipe would so high, that the stream will not make a 90° turn in the funnel, so the 4. cylinder would be hardly handicapped. By the way i have also done a short simulation with the stock intake wich shows up that the two intakes in the middle would take 70% of the flow, if there would be a equal pressure level on each port.

By increasing the pipe diameter to Ø60mm it looks way better, but i am not satisfied and will do some more research on that issue.

Best Regards
Alleslowbuged

[Alleslowbuged]

Hi,

i have reached 189 km with no problems today and have tried to make some power in the last 30 km.
To be honest, i can not say much aboud how it feels, because the vibration and noise level is so high,
due to stiff engine bearing, that i could not really sort my subjective feelings.

The turbo comes later than expected after my calculation with the machbot, boost starts up at a bit
over 2000 rpm, but ~ 30psi are not below 3500 rpm. To spool up it really takes time, so that spectacular
torque feeling is bit missing, but therefore it feels a bit more like an na engine. I was only two time upwards
4000 rpm, but i think that i can say that it feels much more freely to rev in that region as before.

From what i have seen today, i think i have an S2A-69 with A/R = 1,1 intead a S2A-61 with A/R = 1, in regard
to the matchbot calculations, i schould be able to help spooling a bit with more fuel. All values above a with
nearly no smoke at all.

Next step wil be to change the engine bearing.

Best Regards
Alleslowbuged

 

[Alcaid]

Late spooling might be because of a badly matched, is there smaller A/R exhaust housings you could use on that turbo?

[Alleslowbuged]

Hi,

yes could be, i have bought the turbo as "black box" on ebay, so it is not special selected.
Due to the technical data sheet, there should be A/R ratios between 0.5 and 1.0, regarding
my own measurements, my turbine housing is 1.05, but this is not listed.

As i wrote, i have made some new calculation based on a A/R ratio of 1.0 with the matchbot
calculator, whichs shows that even this turbo should be captable to spool early with more fuel.
We will see, i really like the compressor map, so pherpaps i should really try to get a smaler
exhaust casing.

Best Regards



 

[Alleslowbuged]

Hi,

as i have wrote before, i have done some cfd simulations, all with 30 psi boost and flow for @ 200 hp:

stock,


as scheduled, not much better


a bit better with Ø65 mm pipe instead Ø50 mm pipe


here with extra bend, so that the flow come from the upside:


best version seems to be, with flow comes from the front (horizontal)


I will do a bit more rework on something like that.

Best Regards
Alleslowbuged

[BlueMule]

Pssst, Alles, don't tell anyone, but your calculations/simulations should be done one runner at a time. Remember you only have one intake valve open at a time, so the flow does not move through all of the runners at the same time. In fact with a turbo, the intake can act as a kind of reservoir of air. One intake valve opens, allows air to flow in one cylinder, then closes, pressure then builds up in the intake until the next cylinders intake cycle. That is why the stock intake works as well as it does, even though it physically looks like it should not. Now if all of the intake valves were open at the same time, then there is no doubt that the center 2 cylinders would flow the greater percentage of air, but since it is one valve/cylinder at a time, the flow is more even than you might think. Turbulence is pretty bad, but think of this, if the 2 center cylinders took 80% of the air, how would the two outer cylinders fire. Again, the duel plenum is for, 1. reduction of turbulence and 2nd better distribution. At least that what the Rally guys have told me.

BlauMaulesel

[Alleslowbuged]

Hi BlauMaulesel,

you are right, i was a bit lazy bit writing, because i wrote it two time, here in english and in a german Forum in german. As you have correctly identified the cfd's are based on a fixed mass flow at the inlet and a constant (equal for all ports) static pressure at the outlet. I was aware of that flaw, but mainly wand to see the "natural" flow quality of the intake variants and have had no idea how to make a consistence simulation, without time transient calculation. I assume that a intake, which shows up equal flow with less turbulence in this kind of simulation, it will also give a good flow at engine conditions. 

My main reason to swap the stock intake is to equalize the flow (pressure losses) for each cylinder, for sure i also like less turbulence. The stock intake ports, both in the head and also in the lower part of the manifold, seems to be high flow captable, but i do not like the small 90° bend in combination with the even smaller opening on the top. I think it is fully ok, for power up to ~150 Ps but with higher boost and higher flows, i have concerns that the flow will become to unequal between the the middle and the outher cylinder, which will cause badly temperature profiles in the engine and extra load for the crankshaft.

Do you know how "experts" build up cfd simulations for intake manifolds? Do the ask for max. mass flow on each port separate?

Best Regards
Alleslowbuged