Upgrading Fuel System, Fuel Injectors, and Spark plugs!

[rhearne27]

Recently, I have been continuing my modifications to improve my horsepower on my 4.0 V6 2015 T4R. So far, I haven’t done anything too crazy. A simple CAI, exhaust system, (soon to be headers), and I just bought a torque amp turbo kit but have yet to install for this reason. I also had a tuner add a small tune but he couldn’t do much more because of the weird ECU Toyota has. I am concerned that the more horse power I add, my fuel injectors and fuel system won’t be able to keep up.

I’ve considered adding nitrous oxide but said no simply for this reason. Too much money and too much risk. (Note: I know not many people do performance mods to 4runners but I want to try to be the first to fully mod up a 5th gen one).

The torque amp that I mentioned earlier, I really want to add but I don’t want to risk harming my engine and spending more money. Really, I’m just looking for information about the Toyota fuel system compared to aftermarket parts and why I would need to upgrade them. Do I even need new fuel injectors or a fuel system for a basic small 5psi turbo? Or would I be totally fine running stock.

Eventually, I’d also like to add a supercharger too but that’s way in the future. If you guys have any advice or information on fuel systems, I would love some feedback. Fuel systems aren’t much my thing and I don’t know much about them other than the super basic functions they give. I also need some new spark plugs if anyone has any recommendations. Thank you guys! I can also keep you updated with my progress and my hp. My last Dyno Run was 304hp with 317ft lb of torque.

 

[firebirdguy]

Recently, I have been continuing my modifications to improve my horsepower on my 4.0 V6 2015 T4R. So far, I haven’t done anything too crazy. A simple CAI, exhaust system, (soon to be headers), and I just bought a torque amp turbo kit but have yet to install for this reason. I also had a tuner add a small tune but he couldn’t do much more because of the weird ECU Toyota has. I am concerned that the more horse power I add, my fuel injectors and fuel system won’t be able to keep up.

I’ve considered adding nitrous oxide but said no simply for this reason. Too much money and too much risk. (Note: I know not many people do performance mods to 4runners but I want to try to be the first to fully mod up a 5th gen one).

The torque amp that I mentioned earlier, I really want to add but I don’t want to risk harming my engine and spending more money. Really, I’m just looking for information about the Toyota fuel system compared to aftermarket parts and why I would need to upgrade them. Do I even need new fuel injectors or a fuel system for a basic small 5psi turbo? Or would I be totally fine running stock.

Eventually, I’d also like to add a supercharger too but that’s way in the future. If you guys have any advice or information on fuel systems, I would love some feedback. Fuel systems aren’t much my thing and I don’t know much about them other than the super basic functions they give. I also need some new spark plugs if anyone has any recommendations. Thank you guys! I can also keep you updated with my progress and my hp. My last Dyno Run was 304hp with 317ft lb of torque.

i cant really comment on supercharger/turbos needing more fuel supply or injectors, but can say that a friend had a tacoma V6 with a bunch of bolt on mods like headers, underdrive pulleys, exhaust etc & a mild tune but still had completely stock fuel system & never had any issues with fuel supply.

curious if you did a dyno run before any mods to establish a baseline? 5th gen 4runners are rated at 270hp at the crank... 304hp at the wheels would be a huge power increase with the few minor mods you mentioned. accounting for a 15% driveline loss that would be like 75-80 hp from the very basic mods. im sure they increased the power some, but 75-80hp seems a little over rated. rear wheel dynos are notorious for being inaccurate, they are best to use for a baseline, then to show power increase as changes are made.

regardless of that, beefed up V6's are cool. best of luck with the upgrades!

 

[rhearne27]

i cant really comment on supercharger/turbos needing more fuel supply or injectors, but can say that a friend had a tacoma V6 with a bunch of bolt on mods like headers, underdrive pulleys, exhaust etc & a mild tune but still had completely stock fuel system & never had any issues with fuel supply.

curious if you did a dyno run before any mods to establish a baseline? 5th gen 4runners are rated at 270hp at the crank... 304hp at the wheels would be a huge power increase with the few minor mods you mentioned. accounting for a 15% driveline loss that would be like 75-80 hp from the very basic mods. im sure they increased the power some, but 75-80hp seems a little over rated. rear wheel dynos are notorious for being inaccurate, they are best to use for a baseline, then to show power increase as changes are made.

regardless of that, beefed up V6's are cool. best of luck with the upgrades!

You are probably right. My roommate has been going to an auto body shop that has a dyno in it (kinda shady area) and I did 2 pulls about a week ago with all these mods. The first pull was 262 with 239ft lb of torque and the second one was the one I had mentioned before at 304hp. I had just assumed it was my cars temperature rising and cooling but you may have helped me notice that he’s just a shady guy haha.

Your friend with the Tacoma sounds a lot like me. Many bolt on mods with lots of stock intervals as I have slowly but surely began replacing everything. I need to go back to the dyno with a normal stock T4R and get a base line then like you said. I probably need to just find a different tuner instead . Thanks for your input!

 

[firebirdguy]

You are probably right. My roommate has been going to an auto body shop that has a dyno in it (kinda shady area) and I did 2 pulls about a week ago with all these mods. The first pull was 262 with 239ft lb of torque and the second one was the one I had mentioned before at 304hp. I had just assumed it was my cars temperature rising and cooling but you may have helped me notice that he’s just a shady guy haha.

Your friend with the Tacoma sounds a lot like me. Many bolt on mods with lots of stock intervals as I have slowly but surely began replacing everything. I need to go back to the dyno with a normal stock T4R and get a base line then like you said. I probably need to just find a different tuner instead . Thanks for your input!

not saying the guy was shady, just that the majority of rear wheel dynos are not that accurate. you could go to one, then get a completely different number at another. they are not as calibrated or maintained as a real engine dyno. nothing wrong with using them to tune & measure improvements from mods, but need a baseline to go off.

 

[Dillusion]

This gotta be a joke.

TorqAmp if anyone is wondering.
TORQAMP – Boost any engine like a boss!

 

[gamefreakgc]

If the Torque amp electric turbo actually works (which I'm not sold on) you'll want to have a way to modify and tune the ECU. As your tuner found out, Toyota doesn't let you do much to newer ECU's and virtually nothing for 3rd gens, it's never been cracked. If you add a significant amount of airflow in the engine you'll reach the upper end of your fuel system and risk leaning out in the higher boost situations. That's if this actually puts out any significant boost though. Your tuner should be able to add a boost gauge while tuning to see if it's actually doing anything.

You are right though, just adding a turbo of any kind with no fuel mods will end in a damaged engine. No way Toyota would cover it under warranty either.

 

[Ed_C]

$2500 for that electric turbo. Audi does utilize 48 volt electric supercharging but it's in conjunction with traditional (exhaust driven) turbos VIDEO: Learn how the Audi SQ7 TDI's electric turbocharger works

On a Chevy Cobalt 123 hp and torque baseline, 110/113 with the electric turbo plumbed in but not activated, 145/150 turbo operating @ 5psi
YouTube

 

[gamefreakgc]

$2500 for that electric turbo. Audi does utilize 48 volt electric supercharging but it's in conjunction with traditional (exhaust driven) turbos VIDEO: Learn how the Audi SQ7 TDI's electric turbocharger works

On a Chevy Cobalt 123 hp and torque baseline, 110/113 with the electric turbo plumbed in but not activated, 145/150 turbo operating @ 5psi
YouTube

Thanks for sharing that! So it does work. They make a good point though, the turbo itself becomes a restriction due to the airflow needs for larger engines. So for a 4-cylinder, this looks like a legitimate way to increase power with very little work. For the OP's 4.0L V6, it may only be a wash since your forcing a large intake through a little hole and will cause a massive power loss from that aspect alone.

I realize I didn't help at all with the spark plug question. When converting an N/A engine to a boosted one, it's good to drop to a 1 step colder spark plug. I can't say what came stock with the 5th Gen's but I'll take a stab that it is either NGK or DENSO. I've used DENSO Iridium IK-22's and IK-24's in my current engine and I can attest they run great under boost for the 5VZ-FE engine and come highly recommended, however I have no idea if it will fit in your engine or is even the right size. Here's a chart to figure out what plug to order:

NGK (see the heat range chart and move to one step colder):

DENSO Iridium chart (same as above, order one step colder):