If I were to design and build a turbocharger system for my truck (using intercooler, mild boost, around 6-9 psi.) would I be able to run the HP on the stock pistons? Also, I know I would need to upgrade fuel system to match boost levels; I'd do that with an adjustable FPR, but what else would I need to do in order to support this? Also, do you have a program that I could use, or would I need to get a hold of a dyno and get some a/f numbers?

-Flea

 

Hi Flea,

This is not something that will be able to be covered here properly, but here are a few basics..................

Your HP limit on the stock pistons is about 450 HP, I wouldn't run any more than that on the stock pistons.

An adjustable FPR is *not* the way to go, as the PCM will dial that right back out. An AFPR is simply a band-aid that throws more rail pressure at the injectors *all* the time, and so the PCM will dial that right back out over time, and it won't take too terribly long, either. It will shorten the pulse width up due to the gross over-rich condition in closed loop, and will also write to the open loop fuel tables over time & drive cycles. Instead, you'd need to use an FMU (or FRU, all means the same thing), which will increase the rail pressure but only when boost is up, as it's a boost-referenced type of device that works fairly well. (And of course, we're referring to using an FMU as a method to make the stock 19# injectors flow the fuel needed, as opposed to using the correct sized injectors & running at stock rail pressure.)

The *only* way we will provide tuning for a supercharger or turbocharger is with full dyno data to include A/F ratio testing. I'd *never* just send out a program for a custom turbocharger setup without knowing the A/F's & a lot of additional data, that would be fools play to try to do it without proper data.

The bottom line is that the basics of tuning a forced induction motor still apply with a turbocharger just like they do with a supercharger. In this application, a late-model F-150 with a stock motor, the turbocharger would not be the way to go, unless you seriously plan on really building the motor up so you can run significant boost levels so you can make some power down low and BIG power up high, or unless you were to use a very small sized turbo for quicker buildup of boost. Otherwise, your throttle response is going to be poor, as a turbocharger depends on exhaust *volume* to make it's boost, which only happens at heavy throttle & when the rpms are up. This is why you hear the term "turbo lag," and in these heavy trucks, generally speaking, we don't use turbos or centrifugal superchargers because boost is dependent upon exhaust volume and rpms respectively, and thus yields a poor result for a heavy street vehicle.

Just food for thought...........

 

Just kicking around a few ideas. I've considered possibly building the engine's bottom end this summer to handle a significant amount of boost.

I guess I should have better clarified myself when I meant that I would use an adjustable FPR. I meant that I would get a hold of one that is boost variable, and let you do the tuning on new injectors, etc. after I got some a/f #'s.

Guess there is a bit more work than I anticipated. I still may go through with it, depending on how much I bring in this summer.

Thanks for the info as usual Mike!

-Flea

Edit: I'd probably go with a smaller turbo. I'm not looking for ground shaking power, just something with a bit more oomph, and I though about maybe doing something different than a supercharger. Perhaps a T3/T4 hybrid or something like that.

 

Hi Flea,

OK, so you meant an FMU all along, rather than an AFPR (adjustable fuel pressure regulator). That can do the job as long as power is kept below about 450 hp.

It *is* an enticing idea, of course. I'd like to have a twin turbo kit based on a pair of smaller turbo's for very little lag & good power on the big end, and of course, on a built motor.

Twin turbo's can do a fantastic job, I don't know if you've been reading about Jake Lamotta's exploits with his twin-turbo setups for the Mustangs, but he's pretty much got it down to a science. Most of the Mustangs you see with twin turbos in magazines came thru his shop and/or are running his gear. I've spent some time down there with Jake, & it's enough to make you drool.

Let me know if you decide to persue this, it would be a great project!