Compound pics

[n2toh]

I've actually made an excel spreadsheet for calculating compound twin turbo sizing while accounting for intercooling and aftercooling. Most of the parameters are able to be changed.

I sized things out for my own car and bought another turbo but am not quite yet ready to get that on there. It looks like with the stock turbo and a 60 trim T3 I should be efficient all the way down to around 20 or so and up to about 105 psi. Here is the second turbo I will be using



I don't think I will intercool it and just run a single aftercooler due to space and plumbing restrictions. So much boost can be generated that I see no reason to look for every single advantage there is to be had.

Yes I agreee on making the plumbing simple, but I'm concerned (perhaps needlessly) with the final turbo outlet temps.

an example of an extreme measure can be taken to after cool the air charge that was poo pooed on TDIclub is to use utilize waste heat via an absortion cooler.

[andy2]

I had a relatively small ford IC and it actually did an great job of cooling down the air from both turbos,it really suprised me as I thought it would have been to small for two turbos worth of heat.I jammed through the gears from a dead stop and without downshifting I just jammed on the brakes jumped out and grabbed both pipes.I could only touch the pre IC pipe for a second it was that hot,then I grabbed the Post IC pipe and to my suprise it wasn't much hotter than the intake air pipe.

[n2toh]

I just bought a digital camera and I'm not too familar with posting pics etc.. However here is a link containing some pics of my project

        www.msnusers.com/gtdforum/shoebox.msnw

I had to pull my head off due to a headgasket failure at 37 psi,I'm sure that my 12.9 grade capscrews were not tight enough though.I then found the cylinder damage that can be seen in the pics also.

dumb question does the exhaust normaly exit on the passener side on a 1.6L TD?

[andy2]

It usually exits on the driver side.It was a little tricky to fit a 2.5" downpipe on the passenger side between the motor mount and the bottom turbo with that elbow/adaptor though.I was tempted to cut a hole in my hood and run it up through.I'm pretty sure the 2.5" is big enough and I'll do a restriction test to see if it cuts It.

[n2toh]

It usually exits on the driver side.It was a little tricky to fit a 2.5" downpipe on the passenger side between the motor mount and the bottom turbo with that elbow/adaptor though.I was tempted to cut a hole in my hood and run it up through.I'm pretty sure the 2.5" is big enough and I'll do a restriction test to see if it cuts It.

2.5" should be plunty, 3.5" is stock on the 6.6L Duramax 4" for upgrades.

I think the stock 1Z TDI is 2.25".

[n2toh]

vwmike

Do you still have the excell app?

[vwmike]

Yes I do. I'd like to finalize a couple small things on it though before hosting it. I'm sure all of you would be interested to see it.

[malone]

*

[n2toh]

PCP>injector pop pressure=very bad!

Two questions what are the peak cylinder pressures with more than 35PSIG boost and fuel to match, and what is the pop pressure for the IDI injector?

[QuickTD]

PCP>injector pop pressure=very bad!

I don't see this being an issue, other than it would reduce the quality of fuel atomization under heavy load. The fuel must be injected, the pump is positive displacement. No matter what the cylinder pressure the fuel is going in, or the pump will be destroyed.

 If youre worried about backflow of combustion gasses into the fuel system, don't. The cylinder pressure would have to be several times the injector pop pressure to open an injector, the surface area of the pintle that is exposed to cylinder pressure is far less than that exposed to the fuel pressure. Even if the cylinder pressure were high enough to open an injector, the pressure wave would also have to somehow blast through the delivery valve to ever reach the pump internals, impossible under even the most extreme circumstances.

[VWRacer]

...what is the pop pressure for the IDI injector?

IIRC,

130 bar (1900 psi) for n/a engines

150 bar (2200 psi) for turbo engines

[andy2]

Just an update on my project.

We lowered the compression down further from 21.1:1(3 notch HG) to 18.5:1 by installing GM 6.2L pre cups in my 1.9 head.I had done some research on various GM diesel precups finding that there are about 2 different ones for 6.5td and about 3 different ones for both 6.5/6.2 N/A.One of the more rare 6.2 precups had the same outlet shape orientation as our 1.6/1.9 ones :twisted:.We took about a 1/16" from the OD and height on the 6.2 cups as they were thick and tall.We also took about 1/16" from the chambers in the head.Then done some rurther porting to match things up.

I got the turbine housings,exh manifold,pistons,etc creamic coated.I fineally got my total seal rings.I've got the complete k24 reassembled rarther than the k14/k24 hybrid.Done some porting on both compressor housings.I've got a nice bar and plate IC(overall dia 25"x10"x2.5" with 2.5" in/out ports.This engine/IC will go into my new project car 94 golf.

The only major set back now is that I,ve got three out of four con rods bent #2 being the worst It was .025 thou above the deck before and now the rod is twisted and squished down to the point where the piston is below the deck at TDC.Numbers 2 and 3 seem to be the worst,#'s 1,4 are almost fine :?.This I believe is proof as we all well know that the OEM intake manifold gives better flow to #'s 2 and 3 and thats why they broke down first.We will be making some sort of intake to fix the flow issue :twisted:.

I had the 1.9 up to 37 psi boost and the only reason I pulled it apart was to replace a leaking HG.Not beacuse there was any hint whatsoever of a rod(s) being bent,it ran smooth At idle and fired up in the cold on all four :?

Basically now need some sort of better rods.Any ideas?I heard that in the sixties they use to weld supports onto OEM rods before the aftermarket made any :lol:.The 1Z/AHU TDI's use the same dimention rods but I wonder If they are really any different/better at all?

I really sould update more often :oops:

[therabbittree]

very very interesting that you have bent rods..mummn no water ever got ingested or something?....damn i had 35 psi single turbo...before..i want to do my new mech tdi caddy up with a set of twins soon..kkk24 and a hy35 holset.... not looking forward to breaking teh rods or blowing teh headgasket...onanothger note tahstcool you figured out a way to make te gm precups fit..do you have apart # or pics of this before and after?
thnaks, keep up the good work.
Deo

[fspGTD]

Bent rods, that's crazy!  :?  Congrats you're the first I know of to do that in an IDI because of too much boost!  Good call on lowering the CR!  

We lowered the compression down further from 21.1:1(3 notch HG) to 18.5:1 by installing GM 6.2L pre cups in my 1.9 head. ...
We took about a 1/16" from the OD and height on the 6.2 cups as they were thick and tall.We also took about 1/16" from the chambers in the head.Then done some rurther porting to match things up.

Awesome!!  

[BlackTieTD]

ya andy, great work. clever use of the GM parts... can't wait to get a ride in the new beast.