Now, marine engine HP stories are as common as the fish stories. I appreciate there's a certain level of rounding up...

I just had a guy say that he runs marine engines with 11.5 SCR with 8 lbs of boost on 89oct.

Checked out the Weiand boost chart, that stops at 11:1...where 8 lbs boost gives 17:1 Dynamic.

How big would the cams have to be for this to even be possible? I know the boost factor and starting with higher SCR for modern engines is a thing, but physics still catches up. Far more for a marine engine.

was there alcohol involved in this conversation, lmao! True story here, recentlky a transmission customer called my shop, said he needed a price on upgrading his th400 we previously built for around 800 hp to hold 1500 hp. we talked a few minutes, I asked him what his new power was to get to that power level, he said he was boosting his 11-1 572 (sand truck) with a F2R procharger and was gonna use a blow thru setup, go to about 15, 16 psi of boost, engine was in truck and had been running a couple years NA already. I started asking him who was dynoing and tuning it, he said he was skipping the dyno and just gonna tune it himself in the truck. As we talked I asked him HOW he was gonna tune it and if he had a wideband, etc, what fuel. I swear he told me C16 for fuel. So after I gave him some tuning advice it was 100% apparent he had NO CLUE what he was doing, I asked him if his friends were smokers, he asked why. I said because youll have LOTS of little 4.5" diameter aluminum ashtrays to hand out for gifts. so a few days later he called and asked what my dyno schedule was as he was concerned MAYBE he couldnt tune it himself. so he pulled engine out, brought all the stuff to my shop to be dynoed a week later. As he unloaded stuff he had 2 5 gallon plastic lawnmower fuel jugs, I asked him if he bought a drum of c16 or found someplace that had it at pump which Ive only seen it come in cute little expensive 5 gallon cans. He says no, its 93. I asked him WTF I was supposed to do with THAT??? So he says, engine runs fine on 93, it should run fine boosted on 93, right?? It took me 15 minutes to convince him he was NOT gonna run ANY boost on his 11-1 572 on 93 because it was pretty much maxed out on 93 plus a multitude of other issues he was un aware of like fact it was a gen 6 short deck and I wont push one past 850 for endurance like in a boat and 950/1000 for short burst boosted in a toy, cam was tiny and engine had high cyl pressure already, inappropriate valve train, springs, etc. On sim engines reports 640hp na with his miniature cam, not 800. So i told him take it all with you or take carb back and lawnmower gas you brought, bring carb back when its converted to e85, etc plus we needed to upgrade valve springs, push rods, exhaust valves etc, there ARE guys out there that think you can boost the shot out of something on low octane by "pulling a little timing" LMAO, Smitty

Hehehehehe.

That story is a bunch of BS

surely your not implying 80 pounds of boost is excessive? for the engine geeks i do have something cool its 4360cubic inches 28 cylinders and variable speed supercharger with water alcohol injection and a pressure carburetor/injector that i have yet to figure out how it works pratt and whitney built this thing in the early 50s and its a work of art roughly 6x6 bore and stroke 6 something compression it could make 6000hp cranked up

was that the supercharger and turboed ones?

The boosted and water/alcohol injected aircraft engines of WW2 were amazing.

They also had to post guards on the rail cars filled with denatured alcohol.

Back in my youth I had a friend who worked in a local dyno shop (behind the counter, not a tech) but the owner and the other technician had hundreds of stories about people who always had some WILD estimate of what power their engine made, only to find out it was no where close to that, lol! They had a 'wall of fame' in the lobby that displayed the results of their customers' dyno pulls. Good times.

here's my wild estimate of how much power ill be making. I wont lie and say that i could make 3000 HP according to the massaged numbers from my desk top dyno, but realistically I have a stroked 498 with iron heads, I think 8.5:1 compression turbo specific roller cam and twin Rayjay turbos initially set to 5 psi. I'm estimating 600 hp.

years ago Hot Rod (I think) did a chassis dyno challenge at the Goodguys shows. you had to tell them exactly what your combo was, then you guessed what your car would put down to the wheels and Hot Rod guessed what it would do. other than a couple of guys it was hilarious watching the owners brag that they were making 550HP at the wheels and then putting up 360 or so. most were 200 hp or more off every time.