Diesel tuning, one of the best ways to increase performance, fuel mileage, and horsepower. But what is the most unreliable and reliable diesel tune you can put on your truck? Well, that is what we are going to be asking this diesel tuning CEO today in this article. What really makes a tune unreliable or reliable? We will cover these six questions. How does diesel tuning work? What makes a tune good or bad? What is the most common mistake DIYers make when tuning their vehicle? Is it getting harder to tune vehicles with the modern emissions laws and regulations? What is the most unreliable diesel tune overall? That you should not do when you’re tuned.
Today we are inside of GearHead, GearHead Tuning. We are actually doing an interview with Matt here. He is the CEO and owner of GearHead Tuning here. If you guys need diesel tuning, they can take care of you here, or tuning in general, they can take care of you here at GearHead. That being said though, we’re going to jump right into it.
So, Matt, I want to start off with a pretty general question. How does tuning in general work for the average person? Like if they want to come in and get it tuned, how does it work? I mean, generally speaking, you have a device, there’s several different brands, you’re modifying the same software. So whatever the tuner’s preferred brand is, is what gets used. You’re taking the factory calibration, making modifications to certain tables and other parameters, writing it back to the truck, which alters the way the vehicle runs.
How do y’all guys tune it to make sure that the vehicle stays reliable as well, like down the road? You know, it really varies on things like… the rest of the truck. I mean, you can make lots of power, but will the transmission handle it? Yeah. Well, in the calibration on most modern vehicles, you actually tune the transmission at the same time. So that allows it to actually take the extra power and actually have the right amount of clamping force, right hydraulic pressures, things of that nature. It makes it actually handle the power. So you do have a reliable package. And on diesel trucks, especially, you have to watch EGTs. So if you have a pyrometer, it’s preferred to be before the turbocharger. You typically don’t want to see high temperatures above 1200 to 1250 degrees long term. Situations they can run high or whatever. Basically that is just, that’s thermal stress on the engine. So if you go too long, too hot, it can actually cause stress cracks on the pistons or other failures.
And what makes a tune good or bad? Well, it all depends on the tuner actually. The person riding the calibration, you really have to take into consideration, like I said, the transmission tuning that goes with it, to make sure you’re not making more power. The transmission can handle everything being considered. You wanna make sure that it’s a complete tune from front to back. Obviously bad manners. You don’t want to start bad when it’s cold. Diesel trucks have enough problems as it is when it’s cold. You don’t want to actually add to that. So, I know guys like kind of work around that? Like if it’s 15 degrees outside, like it was this morning, how do y’all write tunes to make it start better in the cold? We don’t try to reinvent the wheel. Gotcha. The factory did a really good job developing a calibration. And I mean, they take the things up to Alaska, make sure they start and that kind of thing. So if you stay with the confines of a factory methodology of the program, you’re not going to have any problems, but there’s some tuners that maybe just don’t have so much experience or they try to, what I call reinvent the wheel. And what will happen is they will, you know, zero out tables or do other things that affect the drivability of the you know when it’s warming up and things of that nature and just, I don’t do that personally. So, and it also plays into emissions and things like that.
I kind of got my tuning from out of state or out of country, but what do you see like the most problems with DIYers when they bring their truck in here? Like, what do you see is the most problems, or the most common problem, I guess you could say, with somebody trying to tune their own vehicle? Well, I would say tuning more than just mismatched parts. I mean, you can’t have a 200 horse injector with the stock turbo, for example. You don’t want to do that. Every time you gain something, you lose something somewhere else typically. Your turbo’s too big, oh, I wanna tow 15 to 18,000 pounds on my truck, well, you’re not gonna put a non-VGT turbo on it, for example, that’s, you know, on a six liter, it’s not gonna work, right? Plus, obviously non-VGT has problems in other areas as well, but you just want a well-matched combo, and sometimes people go too big on the injector, too big on the turbo, you need to set your goals before doing any modifications. Say, hey, you know what? I would like to have a reliable 450 horsepower, or 500 horsepower, 550 horsepower truck. What am I giving up to get there? And so a lot of people don’t think about the ramifications of the modifications because they don’t worry about what they’re going to lose. And they, oh, well now I can’t tow. Well, you know, this truck tows my boat every summer or it’s going to tow my camper to the campgrounds. Now I’ve made a truck that can’t tow. So what good is that? So just considering your modifications before you take the plunge, that’s where people make big mistakes.
What do you recommend for modification wise? Like should I put a turbo on before I put injectors in or should I do injectors after turbo? What do you kind of like timeline? Why should I? Do on modifications? Honestly, I would look at downstream first, like transmission mods, torque converter, stuff like that, because even on, say for example, on a stock 6.0. Yeah. Transmissions can hold quite a bit of power. You start having converter issues when you start putting bigger injectors and whatnot, but always think about the rest of the drivetrain first and then start looking at mods. So honestly, if it’s a VGT turbo, not too big, you can run them with stock injectors. So you can run like a stage two turbo, has no problem with stock injectors. We’ve actually done some emissions tests where it works great. It actually has better emissions up top in some cases. But just make sure there’s amount of fuel, especially on a diesel, the amount of fuel you’re putting in, you have enough turbo. Otherwise you’re giving up something. So the larger nozzle you go, obviously more smoke potential, the bigger the nozzle go. But also a bigger nozzle hurts turbo spool because you have reduced your injector duration. So the injector duration is how long it takes to get X amount of fuel in. So you need say a teaspoon of fuel this particular RPM range or engine load, it can only give you a tablespoon reliably. But what that does is it shortens the injector pulse with so much that you lose turbo drives. So it can actually make it laggier, all else equal, by having an injector nozzle that’s too big.
Is that kind of what y’all perfect in the tuning as well, whenever somebody does that? You can’t tune around a mechanical combination, it’s just not right. So it’s just better to have a properly matched combination to begin with and then everything just works. So they gotta get it right off the rip before y’all touch it or like. Well, no, we, I mean, we try, I mean, we don’t sell parts that, that do things like that. So, you know, we try to, for example, let’s just say that you put a 200% nozzle on a stock turbo truck. Yeah. It’s gonna be smoky, it’s gonna be hot, it’s gonna run like crap. And actually we, in the tuning for bigger nozzles, we actually pull fuel out to try to clean up as much as possible. But you know, there’s a little saying you can’t polish a turd. Yeah, exactly, yeah. That’s kind of what you have in that situation. So you just don’t want to have a really bad combination to have to tune around it.
What is kind of the most unreliable tune that you can run on your diesel truck or even kind of vice versa unreliable and reliable? Honestly, reliability is the complete thought process that went into the tuning and the combination of parts. A bad tune is one that you know makes lots of smoke, gets really hot, doesn’t shift well, doesn’t hold the power well, the transmission just there’s lots of ways to screw it up. When it’s right it’s right, when it’s wrong it could you know it’s like a cut with a thousand knives you know just little cuts with a thousand knives still make for a bad experience.
I have a for myself a 6.0 Power Choke. I’m running the SCT X4 that y’all guys sell here. What tune do you guys
