Got Boost? Part 3

It's been a long time since I updated the site. I haven't stopped working on the car, but I've been sidetracked...sorta. Because of the unique clearance requirements of having the D16A1 in the 1st gen CRX's engine bay and because I am an avid DIY'er, I've decided to make my own turbo manifold. Since I am running a half-width Del Sol radiator, I have a lot of clearance in front of the engine. However, the position of the hood latch makes placement of the #4 runner a little tricky. I've been playing with a couple of manifold designs in an effort to find the combination that makes me the most happy. :)

For the time being, the CRX has been returned to "stock" so that I can see the smog referee. I had to undo a lot of the work that I had already done (cams, exhaust, gauges, etc). Once the inspection is complete, I'll reinstall those items and resume. I don't need the car apart to work on manifolds since I have a spare engine (thanks, Paul) on my bench for test-fits.

Here is the bad boy turbo. This is Precision's SC50 and it's an all around great turbo for the strip/street. Specs are as follows:
.48 a/r T3 turbine housing
76 trim (Stage 3) T3 turbine wheel
Oil cooled CHRA
.60 a/r T04E compressor housing
50 trim T04E compressor wheel

This turbo is rated to support 450 hp at the crank. I won't be pushing it near that hard. I opted for the smaller .48 a/r turbine housing (vs .63 a/r) since I'm running relatively low compression (8.5:1) and my redline will be about 7200 RPM. The laggier .63 a/r housing will make more power and might have been a better choice if I had a higher redline and/or higher compression. I got this turbo from Arturbo on honda-tech. I highly recommend him!

Here's the OBD1 ECU (thanks, Paul!) almost ready for the OBD1 conversion. The conversion will take place before the turbo install so that I can get the Hondata setup with the big injectors.

Here is my very sexy Miller Dialarc HF TIG/stick welding machine. This thing is extremely heavy (it was 600+ lbs crated) and has some steep power requirements (it can draw 90+ amps @ 220v), but I love it. It welds sooo nice and produces a very nice and stable arc.

This is the first prototype manifold that I made. It's made of 1.5" sched 40 mild steel and is basically a knock-off of the Max Rev design. People have made big power (500+ hp) on log style manifolds and their simple design makes them easy to make and install. However, I will most likely go with something tubular.

Here is the manifold/turbo combination bolted onto my test-fit engine. It came out pretty good considering the fact that it was a first attempt. All welds were done with 3/32" tungsten, 1/16 ER70S-2 mild steel filler, and about 15 cfh of argon.

The second prototype looks a little different and is more of a tubular design. This design allows for long and smooth runners #1/#4, but the runners #2/#3 are very short. Wastegate placement is also a little tricky on this setup.

I welded the turbine flange on from the inside and outside for added strength.A You can see that this setup does a good job of splitting up the exhaust pulses from runners #1/#2 and #3/#4.

The most efficient manifolds on the market pretty much have one thing in common: a merge collector. The merge collector takes the 4 pipes from the exhaust ports and smoothly merges them together into a low turbulence area that is efficient for turbo spool/power. The drawback is that the collectors are tricky and incredibly time consuming to make. The first one took me over 10 hours! Here is the start of a merge collector.

This is the finished product. You can see how the 4 pipes merge into one and leave a sharp "point" in the middle of the collector. The runners going back to each port are then welded to the collector. This type of collector is what I plan on making for my manifold.

That's about it for now! Between the OBD1 conversion and manifold fabrication, there is a lot of work coming up. I just need to get in and get the the car smogged so that I can resume tinkering. Pictures of the manifold will be posted soon. Stay tuned...

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