I know I'm jumping in on this really late in the game but I figured with the turbo tuning I've done on my various cars I would throw my card in the game to see if I can help at all.

First remember what the truck is built for, low end torque and power. For a turbo setup you actually would want a smaller turbo to decrease lag time to full boost. I can promise you that the two turbos you are getting from coors are more than enough to do the trick. With a larger turbo you will have to get to 3000rpm before full boost is available.

Secondly, no matter what you try to accomplish by changing injectors, regulators or even fuel pump. Non of it will make a difference if the ecu isn't properly tuned. You put bigger injectors, raise the fuel pressure the trucks computer is just going to fight the upgrades until it is told to utilize what is installed.

I know you have said that you are choosing a turbo over a supercharger for heat soak issues. Have you ever thought about a centrifugal supercharger. It would give you instant boost more consistent with the low end torque and power range our trucks are built for. It would be belt driven and could rest where the a/c compressor you removed would normal sit or could be placed where the ace pump would sit. Plus a centrifugal could still have an intercooler attached if you wish.

Just some thoughts but remember why you have the truck to be awesome off road. Now if I'm mistaken and you want to make your truck a drag king be my guest.

 

You could 'crush' the fuel pressure regulator to increase pressure desired. Common practice on turbo applications. Had one on my Audi. Not highly recommend, but definitely works without adverse side effects.

 

The heat soak is a big part, but also the power curve and that delicious turbo sound. I did consider a centrifugal supercharger, but $$$ whoo! And again, dat turbo sound. Plus, it's never been done on a 4.0/4.6 Bosch which is also a big point for me, where as the supercharger has on a P38.

You're definitely right, I want it awesome off road, but I've worked very hard also keeping it awesome and fun on road. She is my daily driver after all. I want something that I can wind out all the way to 5000 RPM without plateuing which, according to my research, those KO3s would pretty early. My truck has become very comfortable visiting the higher RPMs and this is partially to make her a little more fun there, while gaining a little down low.

Correct me if I'm wrong, but why would the ECU try to tune it back with increased fuel pressure only while on boost if the O2s showed that it's not running rich or lean? Wouldn't the MAF read the amount of air, pulse the injectors correctly, and then the fuel regulator just counter act the 5lbs of pressure against the fuel trying to exit the injector?

Thanks for your help, you're not late until the build is complete (or atleast actually started)

 

Never thought about that, might be a good plan. You know what they say, "If it's stupid but it works, it's not stupid."

I haven't responded to your message yet (on vacation, lots to type on my sh*tty phone), but I will.

Thanks, man!

 

First let me ask have you ever heard a centrifugal supercharger? Because it is nothing more than a turbo driven by a belt instead of exhaust pressure they sound almost identical.

As for the ko3 I personally in a twin turbo confine believe you would have more than enough to hold 5lbs of boost all the way up to redline on our engine. If that is really what your worried about have you thought about a kkk24? Volvo uses it on the s60r and v70r in stock form and actually borrowed the turbo from Porsche. I ran this turbo consistently at 22lbs on my S60r until the internal waste gate failed and blew the turbo seals.

As for the ecu thing, I had issues when I got my volvo and just thought I could manual adjust the waste gate or use a boost controller and get the boost pressure I wanted. I would set the waste gate to open at 16lbs, within a day it would be back to 8lbs. I fear the same thing would be true of the rover. You try and up the fuel pressure next thing you know the computer tells the injector to open for less time. Even putting a bigger injector in the rover won't get your more fuel, the truck sees it is running rich and adjust for it. A lot of these trick we knew tuning muscle cars doesn't translate to computer controlled cars. Unless you change the tuning map the truck will always be trying to get itself back to factory speck. Changing a cam is different because you are physically changing the duration and timing of the valves opening, but even without a tune you will never get the true performance out of the cam itself.

Think of it this way. You go out and buy an Subaru STI, buy a cold air intake from AEM that says up to 40 horsepower gained. You slap it on the car after getting a dyne and then dyne again after the intake is installed and you only see 5 horsepower of difference. Now if you had someone go in and tune the ecu to getting cooler but also more air into the intake you may actually get 40 horsepower, it won't be top end but somewhere in the horsepower graph you may see it. I changed everything I need to make 22lbs of boost consistently on my s60r, downpipe with no cats, 3" exhaust out the back, intake, boost controller, oversized intercooler, injectors,throttle body spacer and everything else you could think of. The parts I bought all came together as a kit but I sourced them individually as I could. The kit was supposed to be good for 400 wheel horsepower. Now imagine my surprise when I showed up to have it dyno'd and a 300hp car stock only made 278 on the dyno. I was pissed but after I had it tuned I was able to get 382 to the wheels. They had to change timing, fuel map, injector pulse, even transmission points to get it to do what it needed to do. But in the end I got what I paid for. All I'm saying is don't throw money at something and just expect great results. Everything has to be setup to work together or they will gain power but not the power you expected to see.

 

I have to admit, I haven't. However, I was under the (perhaps incorrect) impression that the turbo sound came through the exhaust.

I have not. I just looked them up and they appear to be about the same price as a T28. Are there any drawbacks to the T28 in this application as opposed to the K24?

Righto, but it *shouldn't* ever run rich. The fuel pressure regulator I chose has a vacuum connector that will read boost pressure and increase fuel pressure at a 1:1 ratio, so the fuel ratio should stay stochiometrically correct full time. Unless, that is, there's a factory pressure gauge somewhere to back it down, which I don't believe there is. I'll have to check the RAVE and see. I'm not being argumentative, I'm just bouncing the ideas off of you. I really appreciate the help and the insight.

 

There is just a lot to consider. You have to have fuel pressure, amount of fuel and air, timing all working together. I didn't take it as you being argumentative at all. I know you have done your research and can tell from previous post you have thought this through very well. I just want to make sure you aren't forgetting anything.

I know you and me use similar intakes we built on our trucks, have you ever used anything to measure the maf percentage being used. I think mine when wide open is using 140% on the map expected airflow, so I know the system is working to put more fuel in to compensate. My questions is where does the factory maf cut off? I haven't looked this up myself but I know from just recently hooking an ultra gauge up and looking at things I was surprised by how much more air the truck was getting than expected.

I am looking to try and find a better maf sensor, plus figure out the fuel map of the truck soon enough myself as I have always wondered why a high compression engine like ours is only puting out 217 on the best engine land rover could send to the dyno. I know cam would be a big improvement. I honestly would love to have a spare engine with nothing but time on my hands to dig into all the number to build a bullet proof rover engine that was actually tuned to get power out of it. I can only assume that rover purposely detuned these things because of all the reliability issues.

 

There is, quite a lot. That's why I appreciate all the help I can get.

Yes indeed, quite similar. I think we just flip flopped out solid pieces and silicon pieces.

40% extra is a lot. Is your truck stock otherwise? If it is, I could only imagine where mine would be reading considering the exhaust, Port and polish and cam. I'll have to see if i can check it through torque soon.

It is mind boggling, the horsepower is pitiful. Even after all the breathing mods I've done and it's still only at 220-230 at the wheels with 12:1 compression on a 4.6 V8. Insane.

I'll do some more digging in the RAVE and maybe give Bosch a shout to see what I can find about the MAF limitations. Hopefully it would be adequate up to 5 lbs since that's the cut off on the injectors also. We'll see.

 

140% of what map?

maf systems (other than lucas 13/14cux) generally dont have a steady state fuel map since the maf reports actual air mass and doesnt require a ve table to estimate it. it does let you get away with many more untuned changes than a speed density system would. not ideal, but usable

 

The 140% was just maf volume. I was really surprised to see that. I got the ultra gauge so I could keep an eye on the new cooling system I put in place plus I wanted to be able to see a little more data the truck was collecting. I was just surprised when I floored the truck to see it read 140% instead of 100%. So I know now the truck is getting more air then expected. So I now am wondering if they intake is just that much more effective, I know those stock pipes are restrictive as hell and the air box design is **** but I din't think our simple mod would see the engine getting an 40% air volume. I think I opened pandora's box getting this gauge cause now I'm wanting to go into tuner mode.