CIH Turbo EFI by RallyBob

[RallyBob]

Originally Posted by namba209 I'm curious Bob, did you or the machinist mark the valve stems before cutting them down at the valve seated position at the valve guide or were they marked at the fully open position at the valve guide?

Nope, that's just the way they are made, I didn't change the spec.

[N61WP]

TGSI used the same type Manley valves in my head. If I remember correctly, they were called Pro-Flow, or Race-Flow to signify the under cut.
Jc

[Washout]

Are these valves the correct length? The sizes seem to match the chevy valves but I recall that they were too long by .100 or so.

[RallyBob]

Stock length Chevy valves are indeed longer than Opel valves. I know that TGSI has his cut down to custom length, I assume to stock Opel length.

I have run stock-length Chevy valves for years, the only real down side is the loss of valve lift. This is a side effect of the longer valves: the geometry change reduces the valve lift. In theory it will also cause uneven wear on the valve tips. Sometimes it does, sometimes not. This is dependent on the length of the lifters, and the base circle diameter of the camshaft.

Bob

[RallyBob]

Well, since I had some paint and my paint gun out today painting wheels, I decided to paint the gas tank for the turbo Manta. Almost looks too good to put under the car...

[namba209]

Yes it does, Bob. And welcome back to the world of production on Opels. Hope you are recuperating nicely. It's been way too long since you've been really active on the site.

[RallyBob]

Thanks Ron, I haven't been working on car stuff much lately. The hand is almost totally healed, and I have nearly regrown the fingernail of my once-crushed finger. This is the worst time of the year for me in general, I abhor heat and especially humidity. But it's been very cool here the past few days so I got motivated again.

I just dug up a few photos from a couple months back. It just shows the difference between the stock WRX turbo I originally intended for this project and the new VF22 turbo I'm going to use instead. The turbine housing is quite a bit larger in diameter as you can see. I still took the time to port the turbine housing inlet to promote faster spool-up time. The second photo shows a stock unported VF22 next to the one I ported for the Manta.

[namba209]

Darn those suckers are small. Then I just remembered, I'm used to seeing turbos on a 3350 cu.in. engine or on an Allison or Rolls Royce 1750 cu.in. V-12. Thinking torque convertor size in diameter. Then I see the coffee cup size in your pics. It just blew my mind. Suffice to say I've never really looked too close at a turbo'd engine in a car before. Anyway, as usual, the workmanship is outstanding and a piece of art for sure. From my motorcycle racing days, the only suggestion I would have is to mirror polish the inside of the inlet so carbon particles from the exhuast won't have a place to grab onto and stick. Once that happens, the particles grow like a fungus inside the exhaust ports, making the port smaller and reducing efficiency. JMTCW.

[RallyBob]

Well, good news. I finally got to pick up the head from the machinist today. The irony as usual is that the head has been sitting down there since May, but the guy only started on the head yesterday. Needed one valve guide, a complete valve job, and a surprising amount of milling to make it flat. There was a 'dip' in the casting between chambers #2 and #3, so it would have certainly blown the head gasket under boost. Maybe this week I can get back to work on this project.....

[davegt27]

i know the feeling i just got 2 heads i had flow tested back yesterday

they had been down there since June

Davegt27

[Travis]

Originally Posted by davegt27 i just got 2 heads i had flow tested back yesterday

How were the results?

-Travis

[davegt27]

oh sorry they where Toyota Heads

dave

[Travis]

Originally Posted by davegt27 oh sorry they where Toyota Heads dave

Sorry to hear that... :P

[RallyBob]

I snapped this photo while the head was still being milled....

After the first pass, you can see the untouched area (low spot) between cylinder #2 and #3....I can only assume from heat. It took three passes to remove not only the low spot, but the corrosion at the coolant passage o-ring area. Not enough anti-freeze in the mix!

[GTJIM]

That pics graphically goes to show that sometimes heads DO need to be skimmed. Also that "anti-freeze" should be used year around for its rust inhibiting quailties. That area between #2 & #3 obviously needs all the cooling it can get - it has been a bit hot on that head at some time - very lucky it has not cracked.

Nice Chamber unshrouding and work in the valve pockets too!

[RallyBob]

Things have been slow here at turbo central. Too much time spent working on my ATV, my winter car, and working late hours at work.

So I have only a small update to make. I made some modifications to the WRX intercooler to make it fit the Manta. As you can see, the stock inlets are on the face of one end tank, and the bypass valve is normally mounted to the intercooler outlet tank. I had to cap these openings off and make another inlet pipe which will be welded in place at a different location.

[RallyBob]

I initially made the bypass valve block-off plate from 1/8" 5000 series aluminum, but a quick pressure test showed it flexed enough to create a leak. So I made a replacement block-off plate from 1/4" thick 6061 aluminum which passed the pressure test with ease.

Here you can see that I first layed out the patterns on the aluminum with permanent marker.

Followed by drilling the mounting holes on a drill press, which is much easier to do before the pieces are cut out from the large plate.

Next I cut them out with a band-saw, which does a nice job rather quickly.

Finally I dressed the edges on a wide-belt sander. Final finishing will be done later on, once I decide what I want to do....paint, polish, powder-coat, satin finish????

[RallyBob]

The intercooler is now complete.

I used a hole-saw to make the oval hole in the intercooler tank for the new tube. I drilled two overlapping holes while holding the tank upside down to avoid letting metal chips into the intercooler core. It took a bit of grinding with a die grinder to size the hole exactly, and for this I used a shop vac at the opening to minimize chip ingestion again. Then a quick pass with the heli-arc and all is well.

[kwilford]

Nice job, Bob. Only one thing. Are you concerned about the loss in intercooling capacity by having all the air flow in one end of the plenum, versus through the two central locations in the stock setup? I read recently about an intercooler project (Was it here? Am I having an Alzheimer's moment?) where even the stock inlet piping resulted in "bypass". In other words, all the air flowed down one side of the intercooler, and it didn't provide as much cooling as it should have (by design). The remedy was to integrate an internal baffle system that diverted air evenly throughout the core, MUCH improving the cooler operation, and significantly reducing the charge temperature (so more HP).
JM2CW

[RallyBob]

Hopefully it won't be an issue. The inlet is almost exactly centrally located, so the outlet side probably won't affect the airflow through the core, only out the 'exit' port. When the car is dynoed I can check localized temps with an infrared pyrometer....I was planning on doing exactly that anyway. I'll check incoming air temps to the turbo, out of the turbo compressor, just before the intercooler, across the face of the core, just after the intercooler, etc. Just for posterity and record-keeping sake.

Bob

[namba209]

Bob, I'm guessing the inlet to the intercooler is at the top and the outlet from the bottom plenum. That being the case, and pneudraulics being what it is, the whole cooler will be pressurized and that pressure will be equalized across the board inside, except where the low pressure of the outlet is. So theoritically two things could occur, the flow will be through the entire cooler and the rapid expansion of air going into the plenum should drop the temp significantly. So it says in the fine print. BTW, another piece of art, I wish I was as talented.

[kwilford]

Originally Posted by namba209 Bob, I'm guessing the inlet to the intercooler is at the top and the outlet from the bottom plenum. ... rapid expansion of air going into the plenum should drop the temp significantly.

As I understood Bob's post, the inlet to the cooler is at the bottom, and the outlet (to the engine) is at the top.
And is there much of a pressure drop across the cooler? I would have thought not, as that would substantially reduce the available boost to the engine. And even if there were some, I doubt that it creates much adiabatic expansion effect (i.e. cooling).
The article I read on the intercooler operation stated that the air will (unless otherwise influenced by baffles) all flow down the near side of the cooler, which results in less effective cooler surface area, and hence less cooling, and hotter outlet air.

[namba209]

Keith, as long as there is flow, there will be a pressure differential between the inlet and outlet. I just reread Bob's post and the inlet is centrally located, so the outlet will be the lower one. What will be significant is the flow in CFM and where the pressure regulator is located. If it is just a waste gate that limits exhaust flow to the turbine then the flow will be determined by the intake valves, if there is a pop-off relief valve in the plenum, after the cooler and in the manifold, then the incoming air will be at a constant rate of flow from the turbo when the throttle is at a constant RPM or under deceleration, and under acceleration the relief valve will be closed and turbo lag should be diminished. Lotsa things to consider, but Bob indicated he'll run a temp check across the cooler to see what happens as far as temp is concerned. I'd really like to be there for that dyno run. Lots of theory here, but the proof or falacy is gonna be in the running.

[RallyBob]

I took the time tonight to measure the capacity of one combustion chamber in order to calculate the true compression ratio of the turbo engine. Even with oversized valves and substantial milling to true the head surface, the final chamber volume was barely smaller than a stock 1.9 chamber, at exactly 52 cc's. Much of this is attributed to the generous chamber unshrouding I performed in order to improve airflow.

Taking into account the head gasket ID and thickness, the piston's compression height, the ring land volume, the valve notches, and the swept cylinder capacity, I came up with a calculated compression of 8.75:1. This is just a bit high for a turbo engine, but it will aid in off-boost performance. Still, with restricted ignition advance, there should be no trouble running 14-16 psi of boost on pump gas. We'll see.

[davegt27]

http://cgi.ebay.com/ebaymotors/ws/eB...933826785&rd=1

injectors on Ebay

Gordon it the only guy i know that up there on your level of tech

his current project is a twin charged 7MGZTE

anyway he might come down on price if it doesn't sell

Dave