entropy_engineering

Hey all, I've been wanting to build my version of a turbo kit for a while and have finally gotten under way. I wasn't going to post until finished but maybe this will keep me motivated.

I'm very fond of the 16 valve motors for their simplicity and feel they're under appreciated because the lousy intake manifolds. This project fixes what I consider the weaknesses by updating the ignition, electronics, intake, exhaust, pcv...going crankcase vacuum, and mostly lack of BOOST.

One of the big criteria for me is low cost and also ease of service. I want all the major pieces to be simple to remove so the car is easier to enjoy. I'm not after massive power numbers until I can build the drivetrain and the spare engine. That being said, the flow numbers on these heads (particularly the euro s heads) are quite impressive. When I see dyno results of turbo 5.0l fox body and turbo 5.3 chevy's etc. I know the potential is there.

entropy_engineering

Need a clean block to work on.

entropy_engineering

And a wild idea...don't mind the wastegate sitting there. It gets lonely.

entropy_engineering

I would like to thank Porsche for leaving those three plugs in the top of the block. Apparently they knew I would need the rear one for a drain.

entropy_engineering

entropy_engineering

entropy_engineering

The drain will sit on an oring. The bracket weighs almost nothing. With the side rails being diagonal it's surprisingly stiff.

entropy_engineering

The headers are 304 stainless weld els. I considered 321 but think it's overkill on a street car.

entropy_engineering

I'll update the header section more shortly. I'm taking a quick moment while it seems appropriate to share a few opinions. Many of you can already see how the header routing will go (at least somewhat). I got pretty lucky here because the round exhaust ports line up essentially perfect with the inner diameter of the weld els. Also, the surface area of the round pipe is about identical to one side of the inlet to a t4 turbocharger. Their is no point at all in having a collector pipe larger in diameter than the size of the primaries. Only one pulse at a time will be traveling up the pipe to the turbo. Going to a bigger size will dampen out the beneficial shock waves that help spool a turbo down low. Imagine a slinky stretched out between two people and one of them pulls back a single rung and lets it go. The wave that shoots across is like the shock wave in exhaust every time a valve opens. Log manifolds or "long distance" turbos lose this benefit as the energy gets dissipated before reaching the turbine wheel. I'm trying to prevent that from happening.


I've had to move on to the intake design before I can finish the top part of the headers, so I'll come back to this later.

entropy_engineering

As a bit of a disclaimer, the intake part here is about to get weird. I wanted large plenum volume and two separate log plenums for simplicity. I considered dual plenum intakes like Audi makes, but felt it's overkill for my needs, especially as big as the plenums are. Before anyone asks about the loss of low end torque because the short runners here's my experience with turbo cars. A boosted car gets to at or near zero vacuum with much less throttle opening than an n.a. car. In my experience you can start to just feel the effects of a turbo before boost even registers, likely because it's already starting to help airflow. Once it reaches .5 psi of positive pressure the power overcomes any loss of inertial ramming from the runners. My turbo should come up pretty fast so...I may have lost some power at 1200 rpm. By 2000 I'm sure it will already be well past stock. Sequential injection and a good timing curve should help that.

I got lucky here as well. The diameter of the euro s intake ports just happens to line up perfectly with a readily available size of aluminum pipe. I wanted some sort of radiused entry for better airflow, but the units like rossmachineracing.com sells I felt were too expensive for what you get. I hunted for better options until I was blue in the face and starting thinking an actual velocity stack would be better. I could get the large plenum I want, but let the runner protrude inside to get some length back. Again, before any runner length arguments start, I don't believe much in guesstimating length when the speed of sound changes with temperature, pressure, etc. it's just not practical. I believe in good airflow and pressures for turbo personally. I finally found a set of die cast aluminum velocity stacks meant for weber carburetors. The dimensions are perfect and they were dirt cheap (like me!).

Here lies the problem. When my friend and I opened the box I casually said out loud, "Man it's a shame to put these inside the intake to never see them again. I almost wish my intakes had glass tops to show them off". And then we stare at each other. And then we stare more. Then I start thinking to myself "Oh God don't let me get obsessed with this now". Too late...

whatudrivin

Will be watching this closely. Not worried about heat from the headers?

entropy_engineering

I'm very worried about the heat from the headers...and the downpipe...and the turbo...and the dump pipe from the wastegate. I'm familiar with this kind of work so I have a few tricks up my sleeve to help. Stay tuned...

entropy_engineering

Apparently when you buy aluminum plate it's not always flat...



I welded some 1/4 by 1/2 rails on to some aluminum plate



To mock up a really bad idea

9x8

I'm very interested in the project being a 16v fan myself.
I also thought about using 16v euS top end over the S4 bottom end for a resulting compression ratio of about 8-8.5 to 1. Then you can go crazy with boost. I think we already have a confirmation that a stock bottom end is good for 800+ whp.

entropy_engineering

I should probably mention, I joke around a lot but do my homework. I've learned more about glass than I ever wanted to recently. Many of you are probably thinking this can't work...which is largely accurate. Tempered glass is great, but once it's tempered it can't be machined or it explodes into a ton of little pieces. Plate glass is too weak. I realized I need a borosilicate family glass, but it's wavy. The problem is pyrex (a brand of borosilicate) sheet was always a bit wavy and is no longer available in sheet form anyway. Leave it to the Germans. Schott makes a product called borofloat. It's strong, has awesome heat shock tolerance, and is machinable by water jet. They also make a big range of thicknesses and have several U.S. distributors. Talk about luck, I even found one with no minimum. The strength modulus is posted on their site, so I put the numbers in to a three point beam equation, added a safety margin, and hear I am still praying it all works. I do have aluminum block off plates for tuning the motor in case I have a back fire. Glass shards in the motor are a real bummer.