Golf II GTD with 1.9 AFN engine --- EVO III

Hi,

thanks for the link. I think i have stored it somwere on my harddisk and read it some couple of years ago, but could not remember before today.

Some nice infos in the paper, especially with measured "hard facts", which i like most. Pherhaps i am a bit self-pleased, but overall i would say that my thougth are in line with the stats from the paper.

I like the comparison chart (Fig. 7 on Page 123) of changed boost pressures with equal fuel injetion at 4000 rpm. Do you agree that the boost pressure is probably in barg and the backpressure in bars? If not, that would mean that the backpresure is nearly 1,0 bar higher than the boost pessure with ~ stock boost with an VNT20 turbo, which i can not imagine.

If we agree that the chart show barg vs. bara, than all three cases shows a postive pressure head (higher boost than emp) and increasing the boost level from 1,6 to 1,8 bar, without adding fuel brings sligtly higher efficiency, less smoke and pullition and reduces the egt from 614°C to 558°C by more than 50°C.

This would be good, as i hope to possibly reach my 230hp goal with around 1,8 bar (26-27 psi) @ ~4500rpm - 4800rpm, with ~ around 82-83% volumetric efficieny due to big valve head and cam. If so, i would like to increase boost by additionally 0,1-0,2 bar to make sure there is more air than necessarry and increase swirl further in hope of incresing the quailty of the combustion as well.

Best Regards
Alleslowbuged

@ ~4500rpm - 4800rpm, with ~ around 82-83% volumetric efficieny

Click to expand...

Probably a little optimistic, even with a ported big valve head and cam. Other data look ok to me. I fully expect both boost and exhaust backpressure to be in bar_g, d.h., exhaust pressure > intake pressure; this is normal at full-load, rated power conditions.

"Charging efficiency" is a confusing term; I think what it means here is a density ratio with respect to uncharged volumetric efficiency. It is definitely not a measure of thermal efficiency (Eff. Wirkungsgrad) or combustion efficiency. The main focus of choosing the higher boost pressure is exhaust opacity and exhaust gas temperature.

Hi,

you will be right regarding the volumetric efficiency. I have not built any DI engine before, so have no feeling for egt temperatures and power vs. boost levels. But i have an egt gauge installed, so i hope to be able to do some aftermath, when the egine is running.

Regarding the barg / bara discussion, i still can not imagine that the emp should be 0,7 - 0,8 bar higher than the boost pressure for 190hp with an VNT20, even if i do not any details of the turbos.

As result of my very rough matchbot calculation there should be always a possitiv pressure head between 5-8 psi with the GTB2060VKLR. By assuming a turbine effciency of 70%, i have to drop the compressor efficieny below 68% or the egt below 1200°F to get a negative head. To come up with ~-10 psi i have to drop compressor efficieny to ~60% and the egt to around 1050 °F. I know that WG-turbos will end up with negative pressure rations at rated load, but would assume that VTG turbos should be always near equal intake- and exhaust pressures, as long as turbine and compressor are not a complete miss match.

Here is the link to the matchbot calculation (to play with):
http://www.turbos.borgwarner.com/go/9C7GMT

Best Regards and looking forward for your reply

P.S.
here is a dyno plot of my E34 525 TDS

-blue (WG @ 1,1 bar) and red (VTG @1,3 bar) are with the same fuel map

- i have done another VTG run with 1,1 bar (as with stock WG turbo) and the shape of the power curve was parallel to the red one, but 10kW lower. This means approximate 35kW more power with same boost and fuel @ 5000rpm, only due to different emp WG vs. VTG

Hi,

here are some pics of the intake:







looks good


not so good


comparison with Pd150 intake










I would love to increase the volume of the plenum and make it a dual plenum, but i can not weld alu und all my attemps to built a "custom" intake did not went well - pherhaps somtime in the future

Best Regards
Alleslowbuged

you need a lot of welder to do thicker aluminum, anything less than 200 amps AC will cause nothing but frustration
I learned this the "throw things across the shop in anger" way.

Hi,

so not much news here. The head and intake are in finnland, the pump and the 0.280 gibonta nozzle are here and wait for installation. I have wait a few day for feedback from the turbo supplier, but get his feedback now. I will send him my manifold an my last used Schwitzer S2A turbo as template, so that he can adjust postion and degree of rotation of the turbo.

Best Regards
Alleslowbuged

Which pump/combination did you finally decide to use?

If it's thick you need to preheat a lot then 200A could work.
Better if you have a 300+ Amps capable tig to do the job.

​Hi,

the head is ready, i get pictures from the porting guy today:












I am counting days (weeks) now...

Best Regards
Alleslowbuged

Hi,

i forget the intake manifold:



Best Regards
Alleslowbuged

oem valves

Hi,

i think it is a typo and that the right digram show 37 / 33mm valves. I ask if the diagrams only shows the effect of porting, as stated, or porting and bigger valves, but wait for answer.

Best Regards
Alleslowbugued

nice you go for 33 ex and 37 intake it can be done with oem seats, marko pirkonnen makes good work, also have a 10mm cam from marko

can you make pictures of the seat angles and the bends of the port

Wow, that head is beautiful! Nice work.