i was researching a tuner for a friend with a gas truck. why is it that with a gasser you can only gain about 20-30 rwhp whereas a diesel you can get a 200 rwhp tune. is it because our trucks are turbocharged? how do diesels have so much unleashed power stored inside? just trying to get some insight. any info is appreciated. thanks

With diesels, more fuel and air= more power. Diesels also have direct injection, which not many gassers have. Direct injection makes more power with better gas mileage. The turbocharger also helps make massive power. single turbos that make 1000+ hp. If you notice, there are gas trucks with Diesels also only use the fuel they need, instead of wasting fuel.

This is just what I have seen, and is not very detailed.
-Brad

The amount of power Gasoline engine can make, ultimately is limited by octane.

Diesel has no such restrictions, it's all about how much fuel and air you can get into it.

The amount of power Gasoline engine can make, ultimately is limited by octane.

Diesel has no such restrictions, it's all about how much fuel and air you can get into it.

x2 Stole the words from my keyboard :cool:

The amount of power Gasoline engine can make, ultimately is limited by octane.

Diesel has no such restrictions, it's all about how much fuel and air you can get into it.

that makes a lot of sense. thanks for the reply.

A gasser also has a very narrow range of Air to fuel ratio that it has to maintain to run. Diesels do not. So you can add a ton more fuel to it. Diesels do have an optimal range, but that don't blow if you go outside that range.

Gassers are also limited b/c the fuel and air gets compressed together and you have to keep them from pre-igniting the fuel. Diesels only compress the air then the fuel gets injected in when its needed.

diesel does have the possibility of more power... but the turbo is the important part.

My old Audi with the 2.7 V6 gained over 100 ft/lbs with just a chip (it was a bi turbo).

For instance does anyone make a chip for the GM 6.2 diesel? Without a turbo I doubt it would do much other than 20-30 HP.

My old Audi with the 2.7 V6 gained over 100 ft/lbs with just a chip (it was a bi turbo)..

I love those engines. :)

diesel does have the possibility of more power... but the turbo is the important part.

My old Audi with the 2.7 V6 gained over 100 ft/lbs with just a chip (it was a bi turbo).

For instance does anyone make a chip for the GM 6.2 diesel? Without a turbo I doubt it would do much other than 20-30 HP.

Well these engines are all mechanical, so no chips for them. The 6.5 diesel's which are computer controlled... you can get a tune for them that says it gains 80hp. No real data to back any of it though.

I wouldn't say the turbo is the more important part... because you are still limited by octane. Sure you could push more fuel to a turbocharged gas engine, and stuff in more boost, but unless you want to run around on high octane fuel, run water/methanol injection, or start changing other parts, your shit out of luck. This of course depends on the engine :)

Well these engines are all mechanical, so no chips for them.

Oh... thought some of the 6.2s were computer controlled. I learned something today! :D

diesel does have the possibility of more power... but the turbo is the important part.

My old Audi with the 2.7 V6 gained over 100 ft/lbs with just a chip (it was a bi turbo).

For instance does anyone make a chip for the GM 6.2 diesel? Without a turbo I doubt it would do much other than 20-30 HP.
No, you can turn the injection pump screw for more power like on the old first generation Cummins engines.

Well these engines are all mechanical, so no chips for them. The 6.5 diesel's which are computer controlled... you can get a tune for them that says it gains 80hp. No real data to back any of it though.

I wouldn't say the turbo is the more important part... because you are still limited by octane. Sure you could push more fuel to a turbocharged gas engine, and stuff in more boost, but unless you want to run around on high octane fuel, run water/methanol injection, or start changing other parts, your shit out of luck. This of course depends on the engine :)


Ide believe 80 hp increason in a 6.5L, But your still also dealing with the limitations of a IDI motor. You could changed the injectors/turbo and twist the fuel screw all the way in on the DB2 mechanical pump and probably make enough power to shit the crank out the bottom. which doesnt take much with a 6.5 anyhow. But to make power with IDI motors you sacrifice reliability. How many 1000hp 12v cummins trucks are streetable?

ALSO, i believe i read it on here that someone had tuned an 8.1L just over the 400hp mark with basically no major modifications and they felt they could go more with better gas.

Any stock part on a 6.2/6.5 doesn't make NEAR enough fuel. And I don't believe IDI is the disadvantage. Notice in my other post i said depends on the engien too :)