TRD/ Magnuson 4.0 Supercharger Tips, Tricks, and Mods

@Musubi3 don't forget to do the fuel pressure Regulator Mod to boost reference your fuel injectors! Congrats on becoming FIed!

 

I went back to page one… what’s the benefit of this? Without it, I don’t see fueling issues and my fuel trims look good.

 

It allows fuel pressure to rise at the same rate as boost, so instead of the injectors fighting cylinder pressure to spray in fuel at it's normal fixed rate (in our case 43.5 psi) as the boost increases, it now has a reference to boost and the pressure climbs at the same variable rate that the boost does.

Ie: let's say you are making 10 lbs of boost. Instead of staying at a fixed 43.5 psi throughout the RPM band as you are stomping on the pedal you are increasing fuel pressure as the boost climbs and ultimately making 53.5 psi.

You'd be surprised how much better the seat of the pants feels after you do the mod and are properly tuned for it.

 

send it!

 

Rising fuel pressure was a thing of the past with FMUs. Way better ways to tune these days while maintain constant fuel pressure!

 

I'd like to hear what @JustDSM has to say about the HPtunes he does and the FPR mod. I think he recommends and does the tune assuming the FPR mod is done? I'm sure if you have monster injectors you can achieve the right amount of fuel with constant pressure, but to me it seems intuitive to have the fuel pressure always be a certain PSI ABOVE the manifold pressure, i.e. the pressure differential across the injector is constant. Perhaps it doesn't matter with stock pully and boost pressures,, since the TRD tune is rich all the time and doesn't seem to run out of fuel without FPR mod. But as fuel demands go up, so too does the duty cycle of the injectors. At some point you won't be able to spray the fuel required without larger injectors, or added fuel pressure. I don't know where that line is, but curious what "the tuning guru" has to say.

 

I just went through several sessions with Justin. We never discussed performing this mod. I was under the impression it was no longer recommended so I never brought it up.

 

interesting, Now I'm even more curious to hear what he has to say. I would assume it isn't a "do it if you want to" kind of thing, where he either relies on it or not. but perhaps the fuel trims can account for it. I dunno, hope he clarifies

 

Ok, I'll weigh in here.

In the 'early' days before tuning these ECU's was a reality, the "FPR Mod" or "Boost Referencing the FPR" was a way for folks to get some extra fuel at part throttle when under boost to help enrich the truck and provide a little extra headroom in the fuel system to keep IDC's down when running small pulleys. People may have done it for other reasons, but as I came into the scene, that's the nuts & bolts of what people were functionally trying to achieve with this modification.

Now that we can configure these ECU's directly, this modification isn't essential (in my opinion) for all applications. We can configure when/how the ECU goes into open loop, while also configuring how much and where (RPM/Air Load) the engine enriches. There are situations where it makes sense to do it and others where it would make little to no difference.

There is specific mapping in the ECU that is used to effectively simulate the effect of the FPR Mod electronically with a fuel modifier table that scales the calculated IPW down when in vacuum. At atmospheric pressure or greater, the airflow model in conjunction with your fuel model will (if properly scaled and configured) will ultimately produce the correct IPW so the observed mixture ratio matches what the ECU is commanding. This is due to the fueling calculation routine in the ECU being configured for a static fuel pressure.

When you go to a boost referenced FPR setup on these vehicles without specifically tuning for it, a few things happen. Most notably, your closed loop (when you're in a vacuum) fuel trims will get wonky. In some instances, it potentially even triggers a CEL if your other mods (mostly related to the intake/MAF housing) are due to the fuel trim error. You'll find the engine will generally run positive fuel trim values from the FPR mod alone, as the fuel pressure is reduced when in vacuum, and the ECU is expecting and compensating for a static fuel pressure in these conditions. There may be a slight degradation in driveability/idle quality, but I would wager most would not notice. Fueling will be 'normal' when intake manifold pressures are near atmospheric pressure. As you transition to boost, the additional fuel pressure will generally produce a richer than target mixture (assuming everything is 100% calibrated). This isn't necessarily a bad thing, depending on the mixture that's being targeted.

Circling this back to what I do when I tune these ECU's.. Unless you mention that you've done the mod or want to do the mod, I leave the factory compensation tables intact, and everything will run honkey-dorey just as Toyota intended. If it's specifically asked for, I will edit the compensation tables to account for the change and everything will fuel properly during vaccum and boost (though you might run slightly richer than our targeted ratio (which is ok). In instances where we've got a pretty heavily modified engine that's moving more air than your typical pulley'd truck, I may request you do the FPR mod to extend the headroom of your current injectors or similar. But to wrap it up, it's absolutely not necessary (in my opinion) if you're not on the extreme end of the mod spectrum with stroker kits, cams, ported heads, stupid small pulleys, etc..

Hope that helps some.

 

excellent. thanks @JustDSM, makes much more sense now. Could be either way depending on how the tune was requested.

 

I have a recent one ( about 1 year old) and when I went to do the butterfly adjustment thing it was already set, so I wonder if I got lucky or it was standard practice now?

 

You probably just got lucky to be honest. Unless Magnuson started tightening up their QA/QC.

 

No adjustment needed on mine (late 2021 purchase).

 

When I finished installing the SC, I installed the supplied K&N oiled filter into the stock airbox. I'd like to move away from the oiled filters and wanted to find out what recommendations you guys have for me.
I'm looking for something that can work well with the SC while still help filter things out in my occasional dusty off-roading. I noticed some using the donaldson powercore for additional filtering, but with the downside of some performance loss. FWIW, I don't mind swapping air filters prior to my outings in dusty areas.

Is it worth checking out AFE's CAI's, or stick with stock airbox options (i.e. AFE Pro Dry OE repl.)?

 

AFE CAI is the way. They have 2 options. The older version is preferred last I heard. That is what I have.
There are also mods and upgrades if you are really trying to up the flow.

Page 1 of this thread covers this topic.

 

If you want a stock filter and not upgrade to a full intake system, AFE power has a stock replacement dry filter option.

https://afepower.com/afe-power-31-10114-magnum-flow-pro-dry-s-air-filter

 

Got the pulleys off today to swap in some NST lightweight ones. Everything but the supercharger crank pulley.



I also have those titanium studs in my garage from Eddie a few years back. So far, the Stock studs have lasted about 20,000 miles and there are still nice and tight.

Part of me says to swap them both out because I’m in there anyways, but the other part of me says don’t fix what ain’t broke…



Stock studs have unknown mileage on them, but are tight and look good…
What does the supercharged board say?

I am running with the gates RPM belt, as I know that has been a topic of speculation lately

 

I’ve also noticed, pretty sure there are supposed to be 3 of these bolts holding the tensioner, right ??!!

 

I also try to subscribe to the "if it ain't broke...don't fix it" philosophy.

But somehow I'll convince myself that it's a modification that is somehow better than the non-broken stock item and therefore, the above adage doesn't apply. I'm fairly certain that's a symptom of being bitten by the modbug.

Eg: the stock pulleys weren't broken but the NSTs are lighter. The stock studs weren't broken but these Ti studs are hypothetically stronger.

With that said... my studs are still not installed. Haven't had a reason to tear apart that area.....and I probably just jinxed myself right there.

Lastly, the Ti studs were the hard work of @Athlaos. I was only involved in the US shipping logistics. Gotta give credit where credit is due.

And holy crap... I want to check the bolts on my tensioner now. Good luck @Sterling_vH111 and let us know your impression on the NSTs.