How high can we safely rev a stock 1993 LS400 motor? With the stock ECU or a programmable??
Now that my 1UZ Celica is up and running, I am thinking about "improvements". My main use for the car is autocross racing. The events are run on very tight courses made up of traffic cones in a large parking lot of airport surface. Only one car runs at a time and the quickest through the course wins. An average course has a top speed close to 70 mph for streetable cars and about 30 turns in 50 seconds. If a car is set up right, you usually will launch in first gear and shift to second fairly quick, but then the rest of the run is just second gear. Here is my little problem. My car has a 3.727 rear end (stock Lexus is a 3.62) and I run 22.8 inch tall tires (alot shorter than the 26 inch high tires the Lexus LS 400 ran). Add up these two factors, and I think I will be running out of second gear. If I manage to either get the Lexus ECU re-programmed, or set up a stand alone box, then how high can I rev a completely stock LS 400 V8 in such a light car. I am getting mixed reports. Some say the early 1UZ's rev limit at about 6300 RPM. Another post claims it is more like 6800 rpm. I know I will be losing power if I just rev it high, but I just want to be able to avoid shifting into third. From some caculations, it look like the rev limiter will hit at about 68 miles per hour. I really want to stretch that over 6700 rpm. So, my motor is all stock original, what do you think I need to change for safe revving to 7000? I may set up a programmable ECU for just when I am racing. It will also have to hold the trans in second, if I don't make the stock ECU keep running it.
Gary M.
Now that my 1UZ Celica is up and running, I am thinking about "improvements". My main use for the car is autocross racing. The events are run on very tight courses made up of traffic cones in a large parking lot of airport surface. Only one car runs at a time and the quickest through the course wins. An average course has a top speed close to 70 mph for streetable cars and about 30 turns in 50 seconds. If a car is set up right, you usually will launch in first gear and shift to second fairly quick, but then the rest of the run is just second gear. Here is my little problem. My car has a 3.727 rear end (stock Lexus is a 3.62) and I run 22.8 inch tall tires (alot shorter than the 26 inch high tires the Lexus LS 400 ran). Add up these two factors, and I think I will be running out of second gear. If I manage to either get the Lexus ECU re-programmed, or set up a stand alone box, then how high can I rev a completely stock LS 400 V8 in such a light car. I am getting mixed reports. Some say the early 1UZ's rev limit at about 6300 RPM. Another post claims it is more like 6800 rpm. I know I will be losing power if I just rev it high, but I just want to be able to avoid shifting into third. From some caculations, it look like the rev limiter will hit at about 68 miles per hour. I really want to stretch that over 6700 rpm. So, my motor is all stock original, what do you think I need to change for safe revving to 7000? I may set up a programmable ECU for just when I am racing. It will also have to hold the trans in second, if I don't make the stock ECU keep running it.
Gary M.
