TT4Ever S/C Build Thread

The "boost port" on the s/c is an intake port. It is a reference for both vacuum and boost. As seen by the boost gauge.

Factory fuel pressure is ~43.5psi, and it is static.

The problem ehich people face, when they have an '09+, is the severe lack of tuning options that are plug n play. As well as user tunable.

The reflash, is inconsistent by record. The open loop preset map of the reflash might be terrific at one elevation and far to lean at another. Might even just vary from truck to truck at the same elevation.

If that owner wants more boost, doesn't want to purchase a wire in aftermarket EMS, and wants the ability to make sure they have enough fuel for the proper AFR in boost, throughout the whole RPM range, and load range, then they are stuck. They cannot just install larger injectors, as that would make the vehicle run like crap.

The simplest answer - increase the fuel pressure.

A 1:1 rising FPR will do that job perfectly.

What if you wanted to run 10 psi on the TRD? Going to need more fuel.

What if your reflash was running lean? And there are quite a few dynos out there that show how lean it can be. 12 - 13 AFRs at WOT.

Needs more fuel.

http://www.xr-underground.com/forum/showthread.php?t=50532

 

The TRD injectors are to small to make the 400 crank HP (there only 425cc i believe it was around 450cc needed), if i wanted new bigger injectors id have to get a whole new tune which is very difficult on an 09+ without hard wiring an EMS right now. So this is the whole point of my FPR to bring enough fuel pressure in without having to burn up my injectors. Torspd gave me a website to visit for exact calculations for exactly how much fuel pressure i need with the 425cc TRD injectors for the 400HP i originally wanted.

The thing is with me though is that i know the truck isnt making 400 (i say this by comparing dyno F/I results from Torspd's thread with my mods & others) so i had to adjust the FPR a bit for i dont run stupid rich AFR's either

The TRD reflash by itself without any extra boost from smaller pulleys will have a safe I.D.C thats at 6 psi roughly

 

I understand the mechanics behind the fpr mod. Im just questioning why do it? I see everyone doing it and ending up with 10:1 afr which really makes no sense. Im hitting 8lbs at sea level with the fpr at the intake port and still getting 11.5:1 at the leanest. I just don't see what advantage people are claiming with the fpr in regards to practicality. You'll make more power at 11-12afrthe and you will at 10 and richer.

Which is the reason why I asked about just leaving the hose at the intake port and using the adjustable fpr to compensate for leaner conditions associated with raising the boost.

And sorry for the boost port/intake port references just trying to keep the concepts simple and seperate.

 

And I understand that 09+ having limited tuning options ... but that's why I was asking about your idc calculations. They should be consistent whether you are stock or making up to 400hp. What will cause changes is either adjustments to fuel map or raising rpms which we aren't doing while sticking with the reflash.

 

So if he's pulling in more air due to smaller pullies, the IDC won't go up due to the need for more fuel to meet the proper afr?

A 100hp jump (roughly stock forced induction number to 400) won't be changing the IDC?

More air in requires more fuel right?

I'm a newb here so I'm not well versed and may have totally missed something, so dont take my question here as a jab.... I honestly just dont see how the IDC is unaffected and would like to be educated.

 

see im also just going off how i always understood things too so i may be wrong.

but yes, there shouldnt be any change to idc unless youre making changes either to the fueling map via a standalone, or raising the rpms. whether youre on stock boost or running 8-9 with pulleys, the ecu doesnt sense a change. this is why you can start to run leaner just by throwing on bolt on parts. stock, i was at around 10:1 afr (the infamous rich trd reflash) but as im running more air through the engine while keeping the fueling consistently the same, im slowly getting leaner.

 

You this hypothetical scenario. Your truck started at 12:1 AFR, before the addition of a smaller pulley or additional after market parts. How would you get more fuel from the when you are restricted to the current size injectors?

By adding fuel pressure.

The reflash has a preset map for closed loop and open loop. When you are in Open loop, and leaner than it should be, the ECU isn't going to make AFR changes to be more rich. It's in Open loop. Doesn't see what's going on.

Your IDC is a relative to the base fuel pressure. Increase the fuel pressure, increases fuel flow, decreases the IDC. Within a range that the injector is capable of.

The primary thing anyone should do first, is have an AFR gauge. Then they can determine their current AFR's and tell if they might need to do the FPR mod. If they go to a 2.7 pulley, they just might need to. If they are just to lean, they just might need to. It all depends on how the individual's truck is running.

 

Yes, as more fuel goes in, more fuel will be needed to maintain the proper AFR, which in turn raises the IDC. If the injectors cannot keep up, or are not commanded to send extra fueling, then you get lean AFR's with the addition of more air.

 

Deleted my comment because it didn't make sense after thinking on it (Edit: Trying to explain the theory of why and I was saying things backwards) lol, but yeah your right on your just forcing more air & keeping the fuel consistent going leaner because of it. You'll be fine where you are since you started at 10.0, I don't even know where I started with my stock pulley but I was 10.8 with the 2.8 then I'm pretty sure low 10's with the 2.7 & FPR

 

With that said I should actually get rid of the boost port hose for a run and leave my pressure consistent at 43.5 to see what AFR's I'd be running then

 

by definition, injector duty cycle is the amount of time it stays open. 100% is maxed out and cant go more than that. although the amount of fuel being expelled is reliant on the fuel pressure, idc is not. idc is controlled solely by ECU influence. with that said, idc is constant on the trd reflash whether you are completely stock or pushing 400hp with stock injectors and increased fuel pressure. thats why im confused as to how youre getting your idc percentages, because it should still be within a safe(stock) limit. not until you start opening up the injectors duty cycle via standalone ECU or even MAF cal, will you start getting close to unsafe idc's.

now, there is a limit to how much fuel you can push through the 425cc injectors when it comes to increasing fuel pressure. this was the problem with the 1st generation tacoma trd superchargers, because they relied on the NA fuel injectors.

 

And with that said, at an "X" psi fuel pressure, an injector is capable of handling "y" amount of HP. Increase airflow, you increase the fuel flow to match. Which in turn equates to a percent increase of the IDC, to its max IDC. I might have made it unclear the way I was describing increasing the IDC before.

Those 425 ccm injectors @ 43.5 psi, are only good for 350 BHP, @ 80% IDC.

So somewhere between 300-315 whp, depending on the drivetrain loss.

I do not know how much power his is making exactly. But with just a few bolt ons, his injectors are near maxed out. If he wanted to run at 90% IDC that would afford a little more whp.

Adding in the FPR mod will increase his fuel pressure to ~49.5 psi, with 6 psi boost. Which means that the effective size would be a 453 ccm injector. Raising the capable BHP to ~ 375 now, while at the same 80% duty cycle. Both of those at a .55 base fuel consumption.

 

Thanks for doing that ^^^ I was gonna bust out the equations but you beat me to it haha

 

sorry i still dont see how youre calculating IDC, but youre agreeing that he is still at the same idc as the trd reflash right, whether adding pressure to fuel injectors or not? at any rate, i originally wondered why he didnt just keep the hose to the intake and raise fuel pressure via the adjustable fuel pressure regulator...rather than how he has it now with it raising fuel pressure at a rate of 1:1 with the rise of boost and then going backwards to lower the overall pressure to 38.5 psi.

id say there should be an advantage doing it the first way.

 

No. I am not saying that he is still at the same IDC when raising the fuel pressure. I am saying that when the fuel pressure is increased, it increases the hp capacity of the injectors. Where it was once at ~315 whp capable @ 80% duty cycle, it would then be ~340 whp capable @ 80% duty cycle and ~50 psi fuel pressure.

http://www.rceng.com/technical.aspx

 

the reason I had to lower it was because I started with a rich AFR at somewhere below 10.0 at 4500RPM's+ when it sat at 43.5 psi so that's why I'm curious if I just left my fuel at 43.5psi with the 2.7 without the added boost pressure

With the boost rising with pressure in roughly around 47psi with full boost to where I am now with the 38.5

 

so now youre at 38.5 base and once boost hits, itll go up to 47.

why not set your adjustable fuel pressure regulator to 47 base and put your hose back to the intake? have you tried to see what kind of AFR youre getting with everything routed like it supposed to be?(fpr at 43.5 and hose on intake) then slowly working your fpr up until you get an AFR youre looking for.

just suggesting, becuase id rather go from a base of 47 and when full boost hits, the pressure is still there..rather than jumping up from 38.5 and potentially being inconsistant.

 

no i never did it first when i installed the FPR because i was under the impression of my IDC getting to high, but thinking things through i wont have to worry about it to much now

I'll start off with the base pressure back at 43.5 and go from there, i dont even think i've got a spot to put the hose to my intake. i'll have to take a look. Clearly its been a while lol

 

let me know how it goes. i really do regret not going with the 2.7 from the start