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Working to add AC back to the car. A GM R4 compressor can just barely fit on the passenger side. Its tight!
0.5" clearance to the scavenge pump Had to make a custom thermostat housing to clear the new tensioner Its a tight fit... Needed to re-locate the catch can up beside the rad overflow Custom Lexus-GM AC line with an ugly Aluminum weld. I need to cut off that steel nut, its floating around on the tube
Went to the dyno again, I've lost track of how many times its been. This dyno operator is local, and has amazing rates. He's very knowledgeable and helped my diagnose a few issues. There is a 6+ psi restriction between the turbo and the intake, and I suspect this is also the cause of the poor turbo spool I am still seeing. Top candidate at the moment is the intercooler. I've got a fancy one with perforated interior fins for better heat disipation, but I suspect this is causing a restriction. I've got a $120 ebay intercooler on the way that has a 24x12x4 core - with hopefully minimal interior fins for less restriction. I have water-meth, and dont need as much cooling from the intercooler - less restriction is the primary goal.
Next Dyno Day! Peak power is 600whp, however it takes too long to spool. Raising the boost may raise the peak power to my current 700whp target, but the spool time means we wont hit that untill around 6000rpm... Dyno operator was super helpful, and suggested putting pressure sensors on the compressor housing, and the intake manifold. This showed a 6 psi drop between the two!!
Built a home-made boost leak tester, and found numerous issues, mostly with the Doorman LS1 intake manifold. Go figure, there is a reason everyone avoids doorman... Home made boost leak tester Doorman did not include a gasket on this pressure port. There was a massive air leak! At first I thoguht the injector was leaking at the o-ring, but the leak is between the top and bottom halves of the manifold. What garbage...
Using a Grannas Racing kit to install a ford 8.8 IRS diff, Eaton LSD and 3.08 gears into the lexus. This load is off to the diff builder.
3.08 should get me up to my 200mph target, and the 4L80 has a very short first gear. Another fun bonus is being able to do 63mph in first gear, which should lead to incredible 0-60 times
Summit racing reached out and offered a full refund on the Dorman Manifold, despite it being on the car for 11 months. I'm pretty amazed by that customer service. The refund on the Dorman manifold financed an LSXR 102mm intake and throttle body. Supposedly these are worth about 40-50 peak HP?.. We'll see
Fitted a vintage air AC condenser behind the bumper support Tight squeeze for the AC Dryer. Just fits under the headlight Some complex hose routings More hose routings.... Taking a charge. It held vacuum overnight with no leaks. The charge is holding too. It was 95F/35C in the garage. With the AC on, it was 68F/20C at the vents. AC install is a success!
The transmission in this car runs VERY hot. I believe this is due to the billet valve body which keeps the line pressure fixed at a very high level meaning the trans doesnt need an ECU. Even with 2 coolers in series, adding the AC Condenser in front of the trans cooler lead to transmission temps rising above 240F when cruising around.
Decided to replace my 0.75" thick cooler with a 400 CFM fan strapped onto the back with a properly designed unit. This one is 1.5" thick, slightly wider, and includes 2x fans worth 630CFM total. With the new cooler in series with the front mounted unit, trans temps are around 200 cruising.
My fan was haphazardly screwed to the back of the cooler with no shroud or ducting. The new Derale 13740 cooler has a nicely designed shroud included. The bent up pipe is the stock Power Steering cooler. Does a good enough job for a straight line drag car. View looking down at where the drivers headlight gets installed Deleted the fog light for some nice direct airflow through the coolers Finished install, with stock PS cooler re-installed
With the Trans Temps nicely under control, the next issue was the Engine temps creeping up when cruising with the AC on. I did some investigating with paper towels to show which direction the air was moving, and found there was recirculation at the bottom of the radiator, where the fan shroud did not reach.
This is the recirculation I was seeing. Blocking this flow with duct tape helped the temps quite a bit - but it makes no sense to me to block off 10% of the radiator.... Designed an aluminum shroud extension which would put the rubber gasket right at the bottom of the radiator The shroud extension is both siliconed and riveted to the plastic shroud. There is an aluminum strip on the inside to help prevent the rivets from pulling through the plastic Shroud gasket installed. Quite proud of this, joining dis-similar materials is always an interesting challenge : )
Removing the old 3.92 open Lexus diff new Drive Shaft Shop axles from Grannas Racing. About 25% thicker than stock, should handle the trans brake no problem Had a local shop build up the ford 8.8 with a 3.08 gear and LSD. The junk yard gave me a super crummy diff out of a Mercury Mountineer with 240,xxx miles. It was in such bad shape it had SPUN BEARINGS! The side bearing races had been spinning inside the housing. Thats a new one for me. The re-build was a success, the diff builder is confident it will be fine Diff installed Grannas racing directs that a catch can is required. Bought a cheap Ebay one and welded on a mounting tab.
One of the largest problems with this car is spool time. The S475 T6 Turbo turbo takes all of first gear and part of second to spool. At the drag strip, sitting on the trans-brake RPMs stick at 2300 and the turbo will not spool.
Doing some research, I've found that switching to an S475 T4 with a 1.0 A/R should bring the spool RPM down to ~3000 on this engine. Speaking with the guys at AGP turbo, they recommended the Z472 Billet Wheel turbo. The compressor side is slightly smaller than the S475, but flows almost the same due to the billet wheel. The billet wheel also improves spool. Win-win-win. The T4 hot side will choke the exhaust slightly, but I am pretty sure the car will be faster over-all if I can actually spool the turbo at the starting line.
Left S475 T6 Right AGP Z472 Left S475 T6 Right AGP Z472 The new exhaust side is much smaller, it had better spool faster.... Prepping for install Changing exhaust flange from T6 to T4
Data log from 2x 1/4 mile passes. O2 sensor failed on the 2nd data log, actual AFR was around 10 under boost.
The Z472 actually spools up when sitting on the trans brake, and the trans brake RPM rises to >3000. Leaving the line with the turbo spooled is an incredible feeling!! Mega-squirt boost control is acting up and oscillating, this is the next challenge to tackle.
The car is a blast to drive with the new turbo. Stepping on the gas spools the turbo at almost any RPM. Full throttle in first gear breaks the tires free every time on the streets - due to the high gearing 70mph in first is possible, lol.
Kyle I love this build and have thoroughly enjoyed watching it. Your a true modern day hot rodder and what you've accomplished out of your garage is just awesome. Love the diff upgrade and turbo change. Can't wait to see more out of this bad boy!
05-22-21, 06:04 PM
