Turbo or supercharge and NA gas engine

Turtle n Peeps wrote:

transamz9 wrote:
Correct me if I'm wrong but I believe the main benefit for forcing air into an engine for towing is the fact that it will give it a significant boost in torque at a lower RPM range. All you guys are thinking about is HP. You could tune the engine to produce the same amount of peak HP but could get a significant amount more peak Torque or at least lower the peak torque in the RPM range to make the towing experience more relaxing. The Fuel mileage wouldn't really change that much. The energy used to move the load won't change much you'll just be able to do it at a lower RPM more often. If anything the fuel mileage may increase a tad.

Any time you add air to an engine (supercharging) you will have to add fuel. It doesn't matter at what RPM. Remember, gasoline engines, unlike diesels need to run in stoichiometry ratios. If you run twice the air (around 14 psi) you will need twice the fuel because you just made your engine twice as big.

Anytime you supercharge an engine you will use more fuel. It takes energy to turn the rotors or impellers and like I said above you need more fuel to go with the air you just added.

I have often hear people say that turbo chargers are free power. LOL, I wish! I've even seen this written in well know books written by people that should know better.

Another problem with supercharging is you have to over fuel to keep things cool and detonation away. This is one of the reasons the Ecoboost gets really bad mileage when towing when it's hot out. Ford over fuels to cool the whole system off...............or they try too. Sometimes it doesn't work and the engine de-rates to save itself.

As far as the big block goes. Sure you can do a CD on a big block but then you have 4 big old heavy pistons you are dragging up and down the bores causing a bunch of friction. And then you have the smog problem with the big bore. That's why Ford went to a V10. Small bore but big CI. It was a good idea and it worked.

Good post.

Also good point on why Ford went from the 460 cube V8. My understanding was exactly as you have stated here .." And then you have the smog problem with the big bore. That's why Ford went to a V10. Small bore but big CI. It was a good idea and it worked. "

I drove a Ford 460 (7.5 liter) V8 for many thousands of miles in an E 350 cab and DRW chassis...with a commercial box. Previously I had driven an E 300 SRW, C & C with a smaller box and the 302 V8. The big 460 with a heavier truck was an absolute pleasure to drive. Never seemed to work hard like the relatively little 302 cube (5 liter) and always had power to spare.

Too bad about the emmissions...same thing killed the Lawn Boy lawn mower 2 stroke...another good engine, but ;):B at the other end of the size scale from the 460.