311s SR20DET Swap Part 2

Major accomplishments have been made since the Feb. 2 installment. These have included 90% completion of the exhaust system, 75% completion of the intercooler plumbing, realignment of the throttle body, install of a torque strut rear axle and fabrication of the TS mount, completion of the alternator clearance patch, a first pass at the alternator mounting, and delivery of the custom radiator and intercooler. I have also assembled a temporary electric lift mechanism for moving the body, which makes the up and down movements a lot easier. Between writing the above and now, the brake, clutch and fuel plumbing have been completed.

The Exhaust-

As was shown previously, the size of the passage through the X-member was increased for a larger exhaust. I used 2.5” round equivalent oval tubing from SpinTech www.spintechmufflers.com for the exhaust with a larger oval tube for the frame patches. I fabricated a custom flange for the turbo downpipe (actually a few because of a silly mistake!) and pieced together oval components from SpinTech. I tried two methods, at the top I cut and patched pieces together to build the geometry and at the bottom I deformed and hammered the pipe into the desired shape. I think the cut and patch method gave better results faster after the same amount of grinding cleanup. I used the provided slip joints in the oval tubing for connections at the bottom of the downpipe and into the muffler. It would be better to be completely welded or have a solid flange connection, but there just wasn’t enough room. I’ll let you know if it leaks! The last 10% for the exhaust will be to add the tail pipe section after the muffler. That one can wait for some time…I forgot to take pictures of the exhaust system before putting the body back on, here are some shots of the downpipe. The second image shows the turbo with the repositioned wastegate actuator under the steering column.

http://www.311s.org/tech/engine/swaps/sr20det2/TRPics2/101 Ex Downpipe.jpg

46KB,
Exhaust downpipe.

http://www.311s.org/tech/engine/swaps/sr20det2/TRPics2/102 Ex Turbo and Downpipe.jpg

32KB,
Exhaust Turbo and downpipe.

Intercooler and Plumbing--


– Here are two pictures of the test fits of the intercooler; does it look like Rusty is smiling at the new addition? Fluid Control Products, Inc. www.fluidcontrol.net fabricated this unit. I was really pleased with their operation. I sent them a drawing, they quoted it quickly and then delivered a quality assembly in short order at a fraction of the cost of some of the other places I had quote.

http://www.311s.org/tech/engine/swaps/sr20det2/TRPics2/103 IP Front Smile.jpg

46KB,
Front Smile.

http://www.311s.org/tech/engine/swaps/sr20det2/TRPics2/104 IP Back View.jpg

32KB,
Back view.

Here is a view of the plumbing coming together. This is the short connection from the intercooler to the throttle body. The funny looking thing is a Blow Off Valve from Blitz. A BOV discharges the surge in pressure when the throttle closes rapidly (typ. during shifts). A friend and fellow Roadster enthusiast has done all of the aluminum welding for me. Without his help, these aluminum welds would be as ugly as my steel welds. Actually, I probably would have had to plumb the whole thing in steel. All of the silicon hoses are from www.turbohoses.com. They were very helpful with some of the custom sizes/shapes I needed for the radiator. Note that the throttle body has been repositioned on the intake manifold. This gives a direct path from the intercooler to the intake plenum. The stock configuration has the throttle body tilted up at a steep angle, which I wanted to avoid. See the red plumbing as an example. This required a small relief in the body rail, but I think it was really worth the effort (visible in the alternator picture). The last 20% of 25% for the intercooler plumbing is to machine an inlet and outlet to the turbo. I wanted to go the extra yard and machine fresh ones instead of modifying the existing ones. Then the last task will be mounting the intake filter and MAF.

http://www.311s.org/tech/engine/swaps/sr20det2/TRPics2/105 IP.jpg

46KB,
105 IP.

http://www.311s.org/tech/engine/swaps/sr20det2/TRPics2/106 IP Red Sample.jpg

32KB,
106 Red Sample.

Torque Strut Rear Axle--

In order to limit wheel hop, I added a torque strut rear axle from a 2L car. Other benefits included brakes with a chance of working and the 3.7:1 gearing. One unbelievable thing, when I inspected the axle I found a lot of play in one wheel. Normal enough to find some play, just the typical dead axle bearing, right? It seems that the PO cold chiseled (or probably “screw-drivered”) the backing plate so that it could be removed over the bearing. It looks like he was trying to change the slave cylinder. This was apparent by all of the retaining shims being bent and jammed into the slave. The only thing holding the axle in was the plastic/steel seal holder. The moral, check everything when you get a new car or part that someone may have worked on previously.

Alternator Clearance Patch and Mounting --

Completion of this patch marks the end of the major frame modifications. This clearance provides just enough room for the belt to stretch and be tensioned. I also made a few more minor cuts around the turbo, some not requiring a patch. I removed the lip from the frame in the region of the exhaust and turbo for more clearance. Then I welded, ground and re-welded for a smooth transition. These can be seen in the previous exhaust downpipe images. My first pass at mounting the alternator is a basic “L” bracket with tube nuts attached. This will hold forever, but looks somewhat goofy. It was really easy to trim and position and trim and reposition while I was trying find the correct location for the alternator. I think I will try to machine something nice now that I know where I want it. The tensioning mechanism is shortened store bought parts from www.McMasterCarr.com.

http://www.311s.org/tech/engine/swaps/sr20det2/TRPics2/110 Alternator Patch.jpg

46KB,
Alternator patch.

http://www.311s.org/tech/engine/swaps/sr20det2/TRPics2/115 Throttle Body Mod.jpg

32KB,
Throttle body modifications.

Radiator and Plumbing --

Here is a picture of the radiator from Ron Davis Racing www.rondavisradiators.com. It took many revisions with their sales guys to get the most cooling into the small footprint while keeping the cost reasonable. It is a very nicely crafted piece and should provide plenty of cooling. Hopefully the fan will not be needed to keep temperatures under control. I was a bit disappointed to find that I might not have enough space to build a functional shroud for the fan but those are the kinds of limitations I have found this kind of project faces almost daily. Now that the final resting places of all of the parts are being locked down, it turns out that I probably will have enough room-a project for a rainy day. A major effort will go into the coolant plumbing, as this is one of the last items to be solved.

http://www.311s.org/tech/engine/swaps/sr20det2/TRPics2/120 Radiator.jpg

46KB,
Radiator.

Simple Electric Hoist --

I mentioned in my last write up that I spend an inordinate amount of time raising and lowering the body of the car. I realized that I was wasting a lot of my work time doing this task. This was because I was using an engine hoist for this job. So I splurged and purchased a pair of 880-pound hoists from the cheap man’s paradise www.harborfreight.com. These units were $75 each instead of the regular $150 (and still are as of this writing). They move very fast and therefore make delicate positioning difficult, but it is possible to lower the body onto the frame with some care. I ensure that one end of the body is supported by the wood stilts when I am moving the other end, as the body could tip side to side due to the way I am holding it. This is due to my garage door limiting where I could mount the front hoist. I put a 2x4 under the body rails in the front, the back hoist attaches to the outer seat belt holes.

Brake and Clutch Masters and Plumbing --

Over the last few days, I plumbed the brakes, clutch and fuel lines. This was a big task made more difficult by cheap tools and stainless steel line. The stainless line beat up the cheap double flaring tool I tried to use. The bending tool just completed the job-it will still bend 3/16” brake line, but not the 5/16” fuel line…Buy the right thing first, don’t bother with the $30 kits out there, go right to Snap-On and get the $100 flare tool, even if you are only going to do a few.

http://www.311s.org/tech/engine/swaps/sr20det2/TRPics2/125 Brake and Clutch Plumbing.jpg

46KB,
Brake and clutch plumbing .

http://www.311s.org/tech/engine/swaps/sr20det2/TRPics2/126 Brake and Clutch Plumbing2.jpg

32KB,
Lines.

That is where I am as of the end of April, here’s to finishing in time to go to Shasta! TR


Copyright (c) 2001-2008 www.311s.org
All Rights Reserved.
Reproduction of material presented here is strictly prohibited without written permission.