My truck, a work in progress
Thursday, April 29, 2004
  Part 14: More changes (4-29-2004)

After driving the truck sparingly for a few weeks, I noticed that there were still a few details that needed attention before I could take it back to the tuner for a final re-tune. (It needs a re-tune due to the lower compression ratio and new camshaft, which will hopefully allow me to run more advance and more fuel, respectively).

One thing that became apparent fairly soon was that I needed to move the EGT probe to the correct location, which is in the exhaust runner, a few inches from the exhaust port. Up 'til now it had been in the downpipe, a few inches after the turbo, and this was giving me readings that were hundreds of degrees cooler than the actual temps.

Another thing that I noticed was that LCE's 2.5" downpipe was cracked along one of the welds. I thought about just fixing this, but why fix when you can improve (one of the the mottos for this project). Besides, the three bolt flange never sealed properly, and I already had a section of 3" flex pipe that I wanted to incorporate into the exhaust, so I decided to redo the downpipe in 3", mandrel-bent stainless. This would give me a 3" run from turbo to tail pipe, and also allow me to move my O2 and EGT sensors. I could also replace the crappy three bolt flange with multiple V-band clamps. (If you're not familiar with gasketless V-band clamps, take a trip to the Burns Stainless web site and check them out.

So calls were made, parts were ordered, and I began mocking up a new downpipe. The clearance between the turbo and the firewall is tight, but with the right pieces you can squeeze a 3" downpipe behind a top-mount turbo.

Here's the downpipe before I added the wastegate vent tube:





Since I was redoing things, I also elected to add some inches to the wastegate vent tube. I don't know that the LCE location was all that bad, but the new pipe allows me to move the wastegate vent tube exit another 12" or more downstream, hopefully moving a source of turbulence further away from the turbine outlet.

Here's the finished downpipe, shown with the turbo:



Damn, that turned out nice! :-)


Finally, here's a shot comparing both old and new downpipes:





I tried taking a few shots of the downpipe in the truck, but they didn't really turn out. But it is a clean fit, and I think I finally have the exhaust system I wanted a few years ago, when I redid the old 2.5" system in 3".

Here's a shot of the modified LC manifold:





The two main modifications are the EGT sensor bung, visible on the #4 runner, and the wastegate pipe gusset. I highly recommend the gusset, as the stock unsupported pipe has a history of cracking or breaking off entirely (just ask me or the several other people I know who had that happen).

With all of these mods now done, I hope to have the truck running again in a day or two. My expectation is that the increased downpipe diameter will give me quicker spoolup and better power. Regardless, these are the last mods I have planned for this engine. Really!!! Once it's runnign again, I'll schedule a tuning date and do some dyno pulls. And then, hopefully, I can move on to playing with the interior ;-)

Stay tuned... 


The ongoing saga of my 1986 Toyota 4x4 truck and its much-modified 22RTE turbo engine.

Return to my table of contents

ARCHIVES
12/01/1999 - 01/01/2000 / 01/01/2000 - 02/01/2000 / 10/01/2000 - 11/01/2000 / 11/01/2000 - 12/01/2000 / 12/01/2000 - 01/01/2001 / 01/01/2001 - 02/01/2001 / 03/01/2001 - 04/01/2001 / 08/01/2001 - 09/01/2001 / 10/01/2001 - 11/01/2001 / 12/01/2001 - 01/01/2002 / 01/01/2002 - 02/01/2002 / 02/01/2002 - 03/01/2002 / 12/01/2003 - 01/01/2004 / 02/01/2004 - 03/01/2004 / 04/01/2004 - 05/01/2004 / 05/01/2004 - 06/01/2004 / 04/01/2007 - 05/01/2007 / 07/01/2007 - 08/01/2007 /


Powered by Blogger