Could you give me clear direction on bow to locate the spill control valve and turn up the fuel? My intercooler is functioning and I've increased boost now I wa t more fuel. Thanks!
All right, here are a few points on tuning the 2LTE. I'll just put it here instead of starting a new thread.
Before turning up fuel on a 2LTE, I think there are a few prerequisites. You should have the cooling system in top notch condition, larger exhaust, a good intercooler, and a pyrometer.
You will need a manual boost controller (
Voodoo V MBC Black w/ Ceramic Ball Manual Turbo Boost Controller Made in USA | eBay ) installed on your turbo, and if you want to go over 14psi (which I do recommend), you will need a Pneumatic speed control valve (
ASC-8 1/4" BSPT Pneumatic Air Flow Speed Control Throttle Valve CLEARANCE!! | eBay). The point of this valve is to bleed the air from the Boost Sensor in a very controlled manner (lower the boost curve).
The reason an intercooler is the key to more power, is when the turbo boost pressure is increased beyond a certain point, it creates a huge amount of extra heat. This means higher EGTs and less dense air going into the motor (fewer oxygen atoms). Once an intercooler is installed, it solves this problem. Now you have dense air, and lots of it (lots of oxygen).
The boost can be turned up a lot. I run 18psi max after the intercooler. This extra pressure has not worn my turbo in any discernible way over the past four years or so.
Having a lot of boost, with cool air, means there is a lot of head room for safely adding more fuel and making more power. I've maxed out my pump and it seems a good match for the boost I'm running (EGT wise).
Turning up the boost is simple, you just need any
ebay manual boost controller. It goes on the boost line to the waste gate and increases the pressure at which the waste gate opens. Note it also takes a given amount of exhaust energy to drive the turbine to generate boost. You may think you've reached the boost limit of your turbo, but from what I've found, adding more fuel will solve this problem.
Now adding fuel part is a little more tricky. First thing is dealing with the computer over boost fuel cut. This is not a sharp cut off. I've found it is a bit more of a progressive thing. Before the over boost light comes on, the computer is already limiting the fuel when the boost gets high. Seems to start happening around 13-14psi or so.
The way to deal with this is the bleed valve that pradocruzer came up with. (
Reducing 2lte egt's) It works really well, in that it shifts the whole boost curve down proportionally. So the idea is to trick the computer into thinking it is seeing a normal boost curve, where really you are running almost double the factory boost. The bleed valve just t's into the boost line to the boost sensor. It allows a certain amount of air leakage to reduce the pressure. It needs to be mounted after the little filter thing (which limits air flow a bit also). Tuning this valve is tricky. A 1/4 turn makes a difference. You want to be as high as possible before the computer starts limiting fuel. Only way to really tell is by seat of pants difference. Note, there is a product from a company called 'TurboSmart' called a pneumatic Fuel Cut Defender (FCD). DO NOT use this, because it leaves your boost curve as it is, and then abruptly clamps the boost at the maximum that you've set. This is impossible to tune to, as the computer will not add more fuel as the actual boost continues to rise past the clamp point.
Once that is sorted out, you can progress to turning up the fuel at the injection pump. It is done on top of the spill control valve (solenoid sticking up from the pump head). (see picture below - for a 1KZTE pump, but it's the same for the 2LTE) There is a little cap there that has to be removed. Underneath is a lock nut and hex adjust screw. Mark and take a picture of the factory setting. Then release the lock nut, and turn the screw in a 1/4 turn at a time. DO NOT turn it in more than 3/4 turn, or the engine will go into run-away! (I experienced this at one full turn, and it is scary!). Run-away doesn't happen at idle, it only happens when the engine speed is increased by throttle, and then it revs really high and does not come down. So once you've adjusted the screw, rev your engine while not driving to make sure this doesn't happen. If it does happen, you need to turn the screw back out while the engine is revving like crazy. It sucks, trust me. I've learned that as you get close to the run-away situation, what you will notice is that when you rev the motor the motor will take longer to slow down when the throttle is realeased. This is a sign you are getting close to run-away. So turn the fuel down a bit, and rev the motor again checking that it returns to idle quickly as normal.
Anyhow, 3/4 turn adds at least 30-50% more power. It's crazy. The extra fuel will likely increase the boost pressure, as more work will be done at the turbo with more exhaust gasses. So you'll have to go back and re-adjust the manual boost controller and air bleed valve accordingly.
It took me a couple weeks of fiddling to get the perfect tune. Even with maximum fuel, I still run EGT's that are about 200F LESS than they were when the truck was stock!! All because of the extra boost and cold air.
If you've had a pyro on for a while, you will know that you hit the highest EGT's when under sustained heavy load in hot ambient temps. So when you adjust your fueling, make sure you are tuning for safe EGT's under the worst circumstances. Around town and with normal highway driving my EFT's are pretty low, but under worst case conditions (towing up big hills in summer for example), they EGT's can end up much higher. My probe is post turbo, and worst case is 1000F. Normally I can never get it that high, and it maxes out closer to 800F. If your probe is pre turbo, shoot for 1200F worst case. With my tune, I never see black smoke at full boost. I can get black smoke before the turbo spools if I floor it, but I can control that with the right foot. I don't really floor it until the turbo has spooled up.
Really makes the motor fun. When I add the methanol too and the weather is cold, the truck rips pretty good!
These trucks make about 35-45 rear wheel hp when stock. Mine is making about 100 rear wheel hp right now (with meth/water on). Really transforms the truck. Doesn't seem like much, but it is about the same that my friends mildly tuned 1HDT is putting down to the wheels!! Not bad at all.
