Hello again
I just like to start here as saying for those of you that have not read my previous post “Everything you need to know about turbocharging your 4g64” I would suggest reading it just to get a feeling on my back ground on this subject, If you’ve read it that’s great. This is going to be of more technical nature so you can try to build it yourself. The topics we will be discussing are: 4g64 design flaws, Compression ratios, Engine cooling, Air/fuel ratios, proper Turbo sizing and fuel needs
4g64 design flaws: This is a great topic to start off on, most of us have the belief that these engines are great, they last forever, as long as you change the timing belts, here in lays the problem, if it were a perfect world it would be a chain, but we can’t go back now (without a lot of time and money) so we just have to deal with it. Which means removing both rotating balance shafts from the engine so this is done by simply cutting the little timing belt for the one this is easy. This lets the engine oil move throughout the block do not remove the shaft this will starve the engine of oil by dumping back to the pan or even better, push the oil into the timing belt cover, leaving the engine altogether. You can remove that shaft as long as you press out the bearings and press in new “cam bearings without oil holes” just to block off the oil dumping back to pan and putting a frost plug to cover the hole in the block A little barbaric for the most part it’s just easier to keep the shaft in there as long as your bearings are tight. Next is the other shaft which is run off the back of the oil pump a little harder to remove so this is my solution, remove the oil pump remove the shaft from the block you will see that the oil is feed from the support front bearing of the oil pump through the shaft to the second bearing. So what I did is cut the end off the piece that goes into the oil pump with just enough meat left to put it in a vice (not the bearing smooth surface use the ruff surface) and run a tap in the hole and run a bolt in it with the best lock tight available, remember that the oil pump bearing is supporting the piece all by itself so don’t leave it to long(3-4inchs), or any bit of the counterweight grind that off. I know what you are thinking, doesn’t this make the truck vibrate at idle yes at 500-750rpm there is a bad vibration but to fix this is to raise the idle to 900-1000 rpm smooth as silk yes there is some compromise that has to be made, but the next time you see the little timing belt take out the large one and wipe out the valves in the head or the bearings on the countershafts get a little worn out and take the bottom end of the engine out you will remember this write up. There are a lot of people out there that believe that the turbo 2.0l 4g63 has oil squirters so there turbo project has to too there is a lot of engines out there that don’t, unless you doing large horsepower per cylinder 75hp+ you don’t have to worry about it, yes it cools the bottom of the pistons but at what cost dropping the oil press in the main bearings, head and turbo we have large forces at work in the bottom end especially from the 100mm stroke of the crank you want all the oil press you can get! Plus the rods are the same as the 2.0l turbo they have a oil feed line running up the middle running oil to the piston and pin. The noisy lifters are another problem they don’t do much damage just a pain showing off your pride and joy to someone and your engine sounds like carp at best. The only suggestion I have is to buy new ones I replaced all eight for $6 each respectively the other is to remove them, put them in your wife’s Jewellery cleaner with a bit of diesel and automatic transmission fluid 50/50 mix and give that a try it worked for us all but one lifter.
Compression Ratios: In the stock 4g64 sohc 8 valves are great for a turbo charging application 8.5:1 perfect!
Engine cooling: Very important there are a few problems with this too first the water pump and that heavy mechanical fan which takes out the bearing in the water pump simple fix remove the mechanical fan and swap it for electric fan make it run all the time. I never had a time where the drifting50 came near to overheating even when drifting (slow speed high angle +34 Celsius day) the water temp only came up to 180 degrees we only have a stock brand new radiator. A aftermarket one would be better but we never needed it. We do have wetter water additive and a cold 160 thermostat installed. What often gets forgotten when building anything turbocharged is, a oil cooler we added a simple sandwich type oil cooler adaptor that fits in-between the oil filter and it’s mount and runs lines to and from a stock turbo talon oil cooler. When you go to buy one, make sure it has an internal temperature regulator so you don’t super cool the oil.
Air/fuel Ratio: One thing that you can’t cheap out on or have a misunderstanding of it. Let’s first talk about the air/fuel ratio on the natural aspirated engine. The regular one wire O2 sensor is of very simple design, it reads a very narrow band around stoichiometric commonly known as 14.7:1 or on a lambda reading of 1.0. The engine computer controls the fuel, by adjusting the amount of fuel being introduced into the variable amount of air chasing itself in a feedback loop. When the vehicle is decelerating the mixture runs lean a 18.0:1-22.0:1, when accelerating the opposite is true a rich mixture of 10.0:1-12.0:1 under normal steady load (flat highway driving) it will tend to run a bit lean 15.2:1-16.5:1. Natural aspirated engines have very different operating characteristic then turbocharged engines. First we only have so much atmospheric air pressure bearing down on us, for the most part it remains a constant but on a turbo you can change the pressure at which the intake manifold operates at, without changing the throttle position you can set the throttle at 50% at idle and go to red line and have a change of intake manifold pressure from a deep vacuum to double-triple the atmospheric pressure. That change must be followed closely by a proper air/fuel ratio. As soon as the boost is enough to overcome the negative in the intake manifold the air fuel ratio should go from (lean) 14.7:1 to (rich) 10.0:1-12.0:1. This aid’s in the cooling of the combustion chamber and having a lower exhaust gas temperature keeping the pistons from getting too hot, and melting them down. This is why you should always use a wideband O2 sensor and (EGT) Exhaust gas temperature probe, both of which must be placed in the gas stream just after the turbine and before any catalytic convertors. (EGT) gauges are often in 0-2000F remember that pure aluminum melts at 660C-1220F so how hot can you run your (EGT’s), with your stock cast pistons? We have been running the truck with temperatures at 1000F just fine no preignition/detonation/knock.
Proper Turbo sizing: This drives me up the wall, people that put the biggest school bus turbo that they can find and say wow look at me look how big mine is, then you go for a ride and the turbo doesn’t even spool up before they hit redline or it hits in the last 1000 rpm big deal. It’s really sad, alot of money spent. I am more for low end torque and running out of steam at the end, compared to just getting full boost and having to change gears and loosing it all. A good way to figure out a good size is to use a turbo that came on the closest displacement on a factory car example would be a 1996 2.5l Volvo with a TD04HL-16T would be a great donor turbo for our 2.4l, it might be to big even. What I use is a 1989 Dodge caravan TE04-13C. What’s great about using these Mitsubishi Turbos is they have internal waste gates this saves you money when building a turbo setup you don’t have to buy a standalone waste gate and more complicated/expense exhaust piping. These used turbos are cheaper because they don’t have the “Cool” factor of big chrome made in china housings. Spend your money elsewhere. I found the aforementioned TD04HL-16T for $60 used, and it’s going to be used on a future ford ranger 2.3l build up. For what some people pay for just a turbo $600-$1000, I can build the whole setup or a good portion of it, you can use a cheap turbo as long as you tune it right. I have seen alot of people get $big$ turbo set up’s and they no real fuel support or tune. I’ve gone for a ride once and the stock computer was trying make up for real lean operation with 20 psi of boost knocking and bucking pulling timing to protect itself, it was awful, but the guy that took me for a ride though it was great.
Fuel needs are often over looked in cheap set up’s. You must buy a 255lph walbro in tank fuel pump, this will help with fuel starvation issues. You need a fuel pump that maintains fuel pressure all the way to redline. You will need a fuel pressure regulator with a fuel pressure gauge for reference, with at least a 1:1 boost to fuel pressure rise to help maintain a fuel pressure to intake manifold pressure ratio. There is also fuel injectors which come in two different resistances high impedance and low impedance. This is very important our trucks come stock with 275cc high impedance injectors about 18ohms of resistance if you try and put the lower impedance 10ohms 450cc injectors from a 2.0l turbo talon 4g63 it will burn out the stock truck computer, it uses transistors that can’t take the extra current flow and the computer will start on fire(after about a minute) there is a way to use the turbo talon injectors the stock talon turbo comes with a resistor pack(sliver) on the fire wall you can wire that in, or you can wire stand alone 10ohm resistor good for 50watts in line with each injector wiring this will give you 20 ohms of resistance and will drive properly without burning up the computer. Last thing you need is a standalone computer which can be very expense, so I suggest a piggy back very easy to tune I use a Super AFC the old model works great and they are cheap.
Good luck on whatever you try and any questions please ask 