Any ideas on horsepower rating for the 3.3L if it wasn’t turbo?

[5tinger]

Funny how we think 260HP NA V6 is slow.

Yet that's fair but more power than your average 4-pot econobox.

 

[LordKOTL]

Funny how we think 260HP NA V6 is slow.

Yet that's fair but more power than your average 4-pot econobox.

Yeah. Tech moves forward and raises the bar. Remember back in the early 70s when you had stock 350's pushing 150hp? And yes, I know they had to detune them for fuel and emissions reasons.

I will say this within the topic of this thread: my old 2008 G6 GXP got 252hp/255lb-ft, and fuel economy-wise it was virtually identical to what my 3.3 Stinger gets: 18-19mpg commute, 29-30 highway, about 400 mile highway range.

Given that the engine was not GDI and older tech, I think a non-turboed 3.3 would be in that range of power or a bit better power, fuel economy, or both.

 

[SRV]

This would be true if the turbos perfectly compressed the air with no increased heat. But in reality, 88% higher pressure does not mean 88% more air molecules. I used 60-65% which gives you around 225-230hp.

You could run the engine without boost and measure IATs, then again with boost, to better estimate how much air you're actually adding, but at that point you might as well just dyno it without boost.

Fellas, the calculations are solid, it's a 200 hp NA engine.

The engine has an intercooler which removes heat from the compressed charge. A best-case scenario for an intercooler's efficiency is cooling the the charge to 10-15 degrees above ambient.

You are simply guessing with your 60-65%. In principle of course you are right regarding the effects of heat, but that is what an intercooler is for, to remove the heat and make the charge denser.

Therefore, the physics behind the calculations stand:

NAhp x Boost = BoostedHp

200hp x ( 1 + 13psi/14.7psi) = BoostedHp

200hp x 1.88 = 376hp

BTW, excellent response regarding the differences between an engine built strictly for NA versus one that will be boosted - as you pointed out, they are NOT the same engines despite being the same displacement.

AND, this is why I would choose an NA V6 300hp versus a 4-cylinder boosted to 300hp. At cruise and not under boost, that 4-cylinder is less efficient under those circumstances due to amongst other things, a lower mechanical compression ratio, thus lowering the engine's efficiency and lower fuel mileage as a result.

 

[rtv900]

Fellas, the calculations are solid, it's a 200 hp NA engine.

The lexus ES350 is a 3.5 liter NA making 302 HP at a normal production car redline.

They sure worked magic with that additional 200 cc's of displacement.

 

[Thomby]

The lexus ES350 is a 3.5 liter NA making 302 HP at a normal production car redline.

But again, being designed as an NA engine, it's optimized for NA, including an 11.8:1 compression ratio.

Even scaling it by 10/11.8 or 84.7% to match our 10:1 compression ratio (again, I don't think CR works that linearly, but I don't know a better way to adjust) you get 255 hp. Scale by another 3.3/3.5 or 94% for displacement and you're at 240 hp.

So I think it's reasonable to bound our estimate between 200 hp (pessimistic as it assumes a thermodynamically perfect turbo + intercooler) and 250 hp (optimistic since pulling our turbos would leave you without the optimized intake runners etc of a NA-designed engine). And getting more specific than that is going to take a dyno.

 

[rtv900]

But again, being designed as an NA engine, it's optimized for NA, including an 11.8:1 compression ratio.

Even scaling it by 10/11.8 or 84.7% to match our 10:1 compression ratio (again, I don't think CR works that linearly, but I don't know a better way to adjust) you get 255 hp. Scale by another 3.3/3.5 or 94% for displacement and you're at 240 hp.

So I think it's reasonable to bound our estimate between 200 hp (pessimistic as it assumes a thermodynamically perfect turbo + intercooler) and 250 hp (optimistic since pulling our turbos would leave you without the optimized intake runners etc of a NA-designed engine). And getting more specific than that is going to take a dyno.

well yeah but I assumed the question is "what would our engine make designed to be NA"
obviously a motor set up for forced induction is going to be horrible without it.
a 3.3 modern engine with a typical 6500 rpm redline is going to be 260-280 easy, hence the ES350
200 is completely ridiculous.
I believe it would only be 200 AS IS simply pulling the turbos and nothing else, but kind of irrelevant considering it's not designed for that in any way.

 

[Thomby]

The original post was asking about the engine's output while showing zero boost, and how much it makes before the turbos spool.

Given that JB4's valet map 8 runs half of stock boost, I wonder if that could be reduced to zero boost (or if the custom map 6 would take negative values to cancel out stock boost instead of adding to it). And if so, how much of a restriction an inactive turbo would be just sitting in the intake/exhaust stream freewheeling...could be a fun dyno experiment.

 

[rtv900]

The original post was asking about the engine's output while showing zero boost, and how much it makes before the turbos spool.

Given that JB4's valet map 8 runs half of stock boost, I wonder if that could be reduced to zero boost (or if the custom map 6 would take negative values to cancel out stock boost instead of adding to it). And if so, how much of a restriction an inactive turbo would be just sitting in the intake/exhaust stream freewheeling...could be a fun dyno experiment.

ok
well yeah that's different. Hell, just two turbos and all that intake piping, intercoolers, etc is a massive drag in itself. Not to mention super low compression set up for forced induction.