99 SC300 daily beater 11 second street tire build.
Hello Folks, some of you may be interested in a mild fairly quick daily driver. The goal was not a high hp street brawler. But rather a something that could be driven daily with all the creature comforts that the car came with stock. The purpose was to not take any of the drivability and ease of driving that Toyota had developed, just to add a bit of performance to the package. The car was a test bed for the purpose to address and to dial in any issues along with finding the weak links for future builds (is300, Sc300 and GS300) that I plan to offer. I prefer to use my own cars for testing so I can offer better products for my customers/friends.
The car is a bone stock 1999 Silver Sc300 with 217K on the clock. Car is overall in rough condition but a good beater that can be parked virtually anywhere without worry about scratches or dents.
First Plan was to install the turbo kit, fuel system and get the car running and driving. I decided to mate the 3" midpipe to the stock lexus Cat back exhaust to keep things quiet and also find the limits of the stock cat back exhaust system in stock form.
Once the car was up and running, I threw it on the dyno and started dialing in the Ethanol tune. At about 8 psi the stock trans would no longer shift on time and the car would hit and bounce off the rev limiter. Although the trans did hold the power while in gear fine, just couldn't hit the trans with power on a shift.
I have a few Aristo A340e transmissions laying around as take offs from JDM import gte engines I have acquired over the years. I decided to do some testing on the Aristo trans before Purchasing a built ATF unit as I had 3 sitting on the shop floor. I did find the valve body to be different as well as the plug had 2 extra pins in the A340le that came out of the Sc300. I decided to swap valve bodies to keep everything working correctly. Before swapping valve bodies, I modified the orfice for the 1-2 and 2-3 shift. I also installed billet spacers in the 1-2 and 2-3 accumulators. I kept the 3-4 accumulator stock as I wanted a smooth 4th gear shift.
Once the transmission was installed and working like a champ, I had to deal with the open differential. I then removed the stock Differential and installed a stock Torsen TT Auto OEM unit in the case. Kept the stock rear gears to not effect the speedo.
After the trans and 3,200 stall was installed, it was time to strap it back on the dyno. Tuning was going great but I decided to keep going. The car was making equal torque to HP at every boost level. Power band was solid all the way to 7,000 rpm redline. At around 17psi I snapped a 2jzge VVTi rod in half and windowed the block. I cant say I was too sad to see the failure. It seams the stock VVTI rods snap around 480-500wtq.
After pushing the car into the stall, I removed the engine and decided to do a mild build with GTE internals. Since the stock vvti block had a large hole in it, I used a TT block that I had purchased from a friend. Stock TT rods were re-conned with ARP rod bolts along with the TT block was line honed with ARP main studs. We decided to try and keep the compression up so I had the machine shop remove .010 off the block deck surface. Also removed .035 off the VVti cylinder head to decrease quench area and close up the combustion chamber. While the valves were out, I decided to do a quick street port and throw a set of Double Ferrea valve springs in the mix as they were extras that I had sitting around. A OEM TT head gasket was used with ARP head studs to button the engine together. Final compression ratio is around 9.8-10.0:1 with the TT dished Pistons.
After a short engine break in, it was back on the dyno to continue tuning. Numbers were still consistent as they were before the at all boost levels up to 16psi. Power did however hold better up top than it did before.
Initial Dyno numbers are.
I had some spark blowout issues above 17psi as I threw the plugs in at a .032gap and didn't feel like removing them and it was getting late. Higher boost Dyno numbers TBA.
Overall impression is this is one fun car. Ive owned 800-1000+whp cars before and I can honestly say, this car is so much fun in comparison. Spool is almost instant and low end response is amazing with the compression coupled with the VVti. The car is whisper quiet as the wastegate is recirculated. The car is no louder than it was bone stock ( at idle and WOT). Just a faint turbo noise can be heard and that's about it.
I did remove the stock Cat back as I have a 3" v band to 2 bolt adapter. With just the midpipe alone the car only picked up 10whp peak at the same boost level (16psi). Im getting old and 10whp is not enough for me to ditch the super quiet stock exhaust system. I think I will keep it for a bit longer. Anyhow I will post some pics from the build and keep the thread updated as things progress. Need to gap the plugs down and run a bit more boost. I will also be running the car at the local Drag strip to get some Et and trap numbers. Goal is to see if I can get it to run an 11.6ET with the stock exhaust and stock air box intact. I am currently still working on getting all the monitors to set as well.
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Ran into a few small issues but it has been resolved. First issue was due to the stock exhaust internally developing a restriction. It appears that one of the resonators or mufflers had a significant restriction. New 3" stainless exhaust system was fabbed up. I used a 3" Vibrant resonator and twin 3" Megan OE-r Mufflers. Nice quiet idle and deep tone under load. Second issue was the stock Wasted spark system. I ran into ignition issues just under 500whp. With my goal of 500whp (mostly because of the stock A340 transmission) I wired a set of GM Lq9 coils up and configured the AEM for sequential Ignition. Spark issue was solved and the result was 619whp@23psi. I will be running the car on the 225 all season Hankook street tires at the track next week to see if I can at least run a 12 and in hopes run a high 11 second pass. Drag radials will be added in the future I am sure.
Car made the 220 mile round trip too and from the track and drag raced flawlessly. Had a great time and was able to reach my goal of an 11 second pass on 225/50/17 a Kumho all season street tires. Boost by speed was dialed in at the track as I hadn't had time to dial it in on the street. Car ran a best of 11.47@128.
Thanks for the positive comments. I will be taking the car back to the track on the 18th. Unfortunately from the last time out, the car ran quicker than the safety equipment allowed. I will be lowering the boost to 20psi and trying to focus on the 60 foot times on the street tires as well as 1/8th times. If I can get the times into the 1.8's, I will crank the boost up and see if I can't get into the 10's on street tires.