1. Is it OK to cover the precombustion chamber like that
with the ceramic coating?
2. Did you ceramic coat the exhaust ports as well?
3 & 4.Are the valves oem or did you use over size intake and exhaust valves? Are the valves "back cut / under cut" to help improve flow?
5. Can you tell us about the AAZ-camshaft with 'R-koneistus' reground
profile. Do you have the lift and duration specifications?
How will this cam affect lower rpm daily driving torque levels?
6. Have you ever had any of your heads flow tested after the porting is
complete? If so, what do the numbers look like?
7. Do you know what the compression ratio on this engine will be when
everything is all done? Because it is a daily driver I am guessing that you will have had to keep it higher than a race engine setup.
8. For the turbo selection process, do you know what this engine will move
for airflow? I have seen numbers for a stock 1.6td and for stock 1.9td, but never flow numbers for a performance 1.6/1.9 engine. It has always been some what of a guessing game. I am sure the ported intake tract and the better intake manifold will increase the number, as well as the work you have done around the combustion chambers.
That's a lot of questions for now :lol:
I look forward to reading your answers.
Jim
Yes, that IS a lot of questions! :lol:
No problem though, I love to reply all the questions you guys might have!
1.
Yes. The combustion chamber can't have un-coated hot spots, besides
the ceramic coating adds a slight layer of matter onto the chamber head, so with one spot not coated, it could cause a sealing problem.
2.
Aki is going to do that, but it's still to do. He's a pretty busy guy now that we all want out diesel monsters ready for the summer
3. and 4.
Valves are OEM AAZ size, but they are 3-way cut/polished. It's a VW 8V specific angle job which apparently has a big effect on total air flow.
And the AAZ inlet valves are slightly bigger than 1.6 ones to begin with.
5.
It's 260 degrees duration and the valve lift is 9,45 mm.
The inlet valve opens at 202 degrees after TDC.
Does anyone have the stock spec?
The cam should enable much more flow on the higher rpm range, but the side effect of less low-down torque is actually a wanted one in my case.
The Jetta doesn't weigh much so low-down torque isn't all that important, but this does improve engine durability. So that's what we wanted, really.
Will see how the cam acts in practice in a few weeks' time!
6.
Not to my knowledge. But Aki is contemplating on getting a flow bench, and then we would really see what makes what in head tuning.
7.
C.R. will be slightly less than typically with a 1.6/1.9 combination.
If someone knows, please tell me what the C.R. would normally be on an AAZ-headed 1.6 - I have forgotten the numbers.
My head has had some material ground off when the chamber was reshaped, the valves sit deeper, and also my .5 mm oversize pistons will have a small effect.
We didn't measure the actual C.R. because we knew that similar engines have worked OK, and have not had serious cold-starting problems.
8.
I'll ask Aki what estimates he's been using for CFM when doing the inlet and head work. As for the turbo selection, we didn't look as much at port sizes and ARs, we used experience in determining which turbo we wanted. An S1BG with 39/46 wheels has performed well on a 1.6, and had exactly the right boost behaviour. The little Schwitzer is very tough (rated at 30+ PSI continuous) and moves a great deal of air considering its size, and has a smooth boost curve to help eliminate unnecessery engine stress.
Now the turbo is getting a 42 mm inducer wheel to better match the high-flowing inlet and cylinder head. It should have about 220-230 hp capacity on my engine once it's done. When I do the Evo2 build with stronger rods, I may move onto a bigger turbo, or put a bigger turbine on the Schwitzer.
