I've come up with my own theory of why a diesel can give you so much more so lets see if I'm right. Feel free to chime in and tell me that I'm stupid at anytime.
Let the record show that he has given us permission. I simply want it one record.
You can chip any vehicle, gasser or diesel, but you don't get as much from the gasser. Why is that?
For a lot of reasons. Here are the big ones...
1.) Adding power in a diesel (up to a point, obviously, I'll explain that later) is just a function of dumping in more fuel. There is no air metering, in a diesel, so they take in as much air with every single intake stroke, whether at wide open throttle or at idle (assuming naturally aspirated, we'll get into turbocharging in a minute). So, until you get to the point to where there is not enough air in the cylinder to burn all of the fuel, you continue to add more and more power. From the factory, diesel engines come "defueled" from what their actual potantial is for emissions reasons, and also because the manufacturere doesn't want to warranty a tranny stuck behind a 400 horsepower 7 liter V-8. Simply put, they sell lots of them at 220 horse (or 300, or whatever) so why put more effort and money into stouting them up to handle 450?
On the flip side, adding power in a gasser takes a bit more than adding fuel. You have to add fuel, but at the same time, the correct, metered amount of air to combust the fuel, and also have a hot enough spark at the right time in order to burn it all efficiently. So, in a gasser, you can addmore fuel by upping fuel flow, but then you need to replace the throttle body to allow more air in to mix with the fuel. You then have to upgrade the ignition to provide enough spark to ignite all that.
To get 80 horse out of a diesel, you just up the amount of fuel you inject. To get 80 horse out of a gasser, you just up the amount of fuel you inject, up the amount of air to mix with the fuel, up the spark to ignite it all, and also probably have to open up intake passages and put a bigger cam in it to let it breathe enough air to offset the fuel being injected.
So a chip can't do it all by itself in a gasser like it can in a diesel. Mostly, a chip in a gasser just screws around with timing curves to give you better throttle response, etc. it cannot add more fuel unless you do physical mods to the engine, or else it will enrich the mix and make your stuff run like crap.
Add turbocharging to the mix, and you get WAY more air to feed WAY more fuel, and the more fuel you put in, the more air you get, so it really helps out in both cases, but again, in a gasser, you have to open up passages via cams, porting, etc to really make it take effect. Also, you still have to upgrade your spark.
What I do know is that the factory tunes the computer for the lowest emissions possible. It would make sense that the gasser is already a cleaner burning engine and the performace lost is minimal.
Performance lost in both cases is minimal. Both burn pretty clean nowadays.
As far as the diesel, the performance has to be lowered more so to get the cleanest burn.
Not necessarily true. Emissions only hold part of the reason why most light duty pickup diesels are so de-rated. The other part of the equation is trannies, rear-ends, etc. Ford doesn't want to warranty an E40D behind a 350 horsepower engine. They don't want to warranty a torqueshift behind a 400 horsepower engine. And they sell trucks like hotcakes at the factory rating, so why woprry? Recently, they have been playing horsepower wars, and it has cost them all a buttload of money buying trannies, chasis, rear-ends, etc that can hold up to the abuse.... Chevy went with Allison, Ford made their own, and Dodge used a Daimler, but the end story is that all of them spent some money getting it done.
That being said, when you chip the engine, you don't care about the emissions
Or the warranty, or the longevity (at least as much as Ford does...)
and are going for economy or performance or whatever. Therefore, the diesel has a larger margin from clean emissions to highest performance than the gasser. So after all of that, do I have the right idea or does that sound pretty stupid. I just want know if I'm thinking about this the right way, I'm trying to get it all figured out.
Again, emissions has not a lot to do with it. Or, to be more clear, is not 100% of the driver for it. It may be part of it, but not all of it.
Again, a big part of it is the turbo on diesels. It is kind of a self-serving prophecy. The more fuel, the more air, the more air, the more fuel, the more fuel, the more air.... etc. You get the point. It builds on itself like no NA gasser or deisel could possibly do.
An NA diesel only has about 20 or 30 HP in it before you can't make anymore, so a big part of it is the turbo.
