[0Camus0]

I know might be a stupid question, but for the sake of curiosity, what would be the peak power and torque of the S58 at sea level with no forced induction?

It's not straightforward to know, the engine is tuned for the forced induction so the stock map would produce lower numbers than it should, but say you remap the ECU to extract the max power.

Since the engine has lower compression than NA engines, I would think the power might be around 250 whp or so.

Just my guess, but maybe someone here may have a more educated guess.

[mike@x-ph.com]

Since it's meant to run with turbos, checking power without it does not make sense, to be honest.

If your boost is 0, you can increase ignition timing by 10+ degrees, that's going to get you over 100 whp more power

if you are running same ignition time but zero boost, i expect ~200 HP

[0Camus0]

Originally Posted by mike@x-ph.com

Since it's meant to run with turbos, checking power without it does not make sense, to be honest.

If your boost is 0, you can increase ignition timing by 10+ degrees, that's going to get you over 100 whp more power

if you are running same ignition time but zero boost, i expect ~200 HP

Yeah, as I said, the engine is tuned to have forced induction anyway, just curious about the engine power output under 0 boost.

Thanks for replying.

[FC4]

212.6 WHP.

[Info@mad-us.com]

Originally Posted by FC4

212.6 WHP.

I concur. Pistons are made for boost so it probably makes around 200ish hp NA.

[DO444]

I know nothing about any of this.
Can anyone point me to a good resource where I can learn about engines, turbos, boost, etc.

Not trying to become a walking manual, but just to understand the basics and be able to follow a conversation.

I have a basic understanding of vehicles, but the last time I was taught anything was when almost all cars had carburetors (I know you can have both, but it doesn’t seem very common).

Any good resources out there?

[Forzanerazzurri]

Gotta be half at most. It's pushing almost 200hp/l. NA engines outside of Ferrari make 100hp/l at most and that is when they are optimized for their purpose.

[mike@x-ph.com]

Originally Posted by DO444

I know nothing about any of this.
Can anyone point me to a good resource where I can learn about engines, turbos, boost, etc.

Not trying to become a walking manual, but just to understand the basics and be able to follow a conversation.

I have a basic understanding of vehicles, but the last time I was taught anything was when almost all cars had carburetors (I know you can have both, but it doesn’t seem very common).

Any good resources out there?

This forum is the best source; it's filled with information.

[DO444]

Originally Posted by mike@x-ph.com

This forum is the best source; it's filled with information.

Yea that is true, didn’t want to ask basic questions and look like a total noob.
But, ok ha ha… I might as well now!

[Info@mad-us.com]

Originally Posted by DO444

Yea that is true, didn’t want to ask basic questions and look like a total noob.
But, ok ha ha… I might as well now!

Maybe do some reading on compression ratios. since boosted cars run low compression you will understand why the engine doesn't make good power without turbos.


See a good video below

[reNT]

One thing that had always confused me is why the compression needs to be lowered on an FI motor? If the compression is higher, then wouldn't less boost be needed to achieve the same power output? Like for example the S58 has a lower compression than the B58 so the turbos need to produce more PSI to achieve the same power as the B58, which needs less PSI.

So why not just keep the compression higher and have less boost? I know I am missing some key factor here, maybe someone can enlighten me.

[bri1042]

Originally Posted by reNT

One thing that had always confused me is why the compression needs to be lowered on an FI motor? If the compression is higher, then wouldn't less boost be needed to achieve the same power output? Like for example the S58 has a lower compression than the B58 so the turbos need to produce more PSI to achieve the same power as the B58, which needs less PSI.

So why not just keep the compression higher and have less boost? I know I am missing some key factor here, maybe someone can enlighten me.

The video that was posted above is pretty informative and well-done.

[reNT]

Originally Posted by bri1042

The video that was posted above is pretty informative and well-done.

Indeed. So the answer to my question is that because a pound of boost increases the engine's power by more than an equivalent increase in the compression ratio would.

[Info@mad-us.com]

Originally Posted by reNT

One thing that had always confused me is why the compression needs to be lowered on an FI motor? If the compression is higher, then wouldn't less boost be needed to achieve the same power output? Like for example the S58 has a lower compression than the B58 so the turbos need to produce more PSI to achieve the same power as the B58, which needs less PSI.

So why not just keep the compression higher and have less boost? I know I am missing some key factor here, maybe someone can enlighten me.

Reduce knock and you can jam more air into the cylinder since it will have more cyl volume with all else being the same. Remember one is pressurized while the other isn't.

[vetteflier]

Another thing which is counter-intuitive is running leaner improves performance. You would think rich = more gas, = more power. Not so. Of course, there is a line that you can't go over without potentially burning holes in valves. But canned tunes for GM 8s always leaned things up, as the factory ran pig rich just to protect the engine. Of course, altitude (atmospheric pressure) comes into it, as well as compression and fuel octane.

[geko29]

It's gotta be quite low, I'd think somewhere in the mid-upper 100 whp range.

Not an S58, but I have driven my tuned M57 diesel 335d without the small turbo before, due to a vacuum leak. My specific leak prevented the bypass valve leading to the big turbo from closing, thus the small turbo could never spool.

It was hilarious. From a stop it was probably the slowest car I've ever driven--we're talking 10+ seconds to get to ~15mph with the pedal on the floor. Right around then, the big turbo spooled, it melted the rear tires and took off.