hogie roll

Theoretically 6psi on a 710hp NA engine would get you 1000hp. Not counting the power it takes to spin the blower. How much power do they take?

I'm guessing it would have to be something like an 800hp 540 if it were naturally aspirated, which is quite tuned up!

mike tkach

iTrader: (3)

my engines run at 33 to 34 total,on the dyno at 32 the egt,s were going a little higher than i liked.at 33 they were high 12s and low 1300s.i do run them a little on the rich side at wot,10.2 to 10.3, in the boat.i run 8.6 to 1 comp ratio.i am pretty sure merc uses inconel exhaust valves in all their supercharged engines and some of the na engines.i agree that with less compression you can get away with a little less timing but i see no reason to do that.t mone claimed just south of 1000 hp with 6 lbs boost with non innercooled 540 with 8.71.he is not doing that with 7.5 to 1 compression ratio and a pair of 750 carbs.when i make hp claims i have dyno sheet&facts to back up my claims.one of my boats had 540s that i built,they were innercooled with 8.71 and 850 carbs and 950 hp was the wall with a safe tuneup.i am not picking on him but i would like to see facts to back up his hp claim.i have done a lot of dyno testing on this type of engine through the years and i have learned what works&what does not.also like to add that droping the total timing 2 deg can loose 50 hp,so i question why anyone would spend good money building these engines and then not take advantage of what the engine can safely produce.

Bawana

Thanks Mike.... couple other questions for ya.... have you ever run like 32 or 34* with an afr at around 11.7 or higher? What egt's were you getting at 32* and any numbers at 30* when you dyno'd your motor? 50 hp by 2* drop, .... that is a kick in the nads... but ya if the motor wants more, then I guess. Do you run 91 or 93? Detonation just scares me & I have enough JE ashtrays sitting around, but this summer I m thinking of upping my timing, not for the power but for those over 15 minute WOT runs. I also have enough junk vales on the shelf.... At least with the burnt pastons you can use them for ashtrays... is there any use for the junk vales? lol

MILD THUNDER

iTrader: (3)

Keep in mind, you can get away with a bit less total timing with a projected tip plug, as you are running.

Engine speed, cylinder pressure, cam design, chamber design, piston design, stroke, spark plug style, air/fuel ratio, all play a big role in making up the tune. As engine speed increases, so can the demand for more advance. An engine spinning 5000RPM max, might want 30* of total timing, but a similar setup spinning 6000RPM might want 34*.

The 800sc only ran 28* total. But it was also a longer stroke engine, running 8lbs of boost, with a max engine speed of 5000ish. The 525SC, ran 35* total timing, but was a shorter stroke running less boost.

I've been running 32 and 34* on my 9:1, 4'' stroke engines with 6psi at 5700RPM, with afr around 11ish at wot. I would not attempt that with an RV cam and propped for 5000RPM with my engines.

Black Baja

iTrader: (2)

It takes about 10.5:1 a good set of conventional heads with extra work done to them to make 800 at 6300 with a 540. A 540 with an 8:71 pump gas 6300 rpm 1000hp.... Nope don't see it. Not at that rpm range.

T-Mone

Morning, this will be my last post about this as i am not in any competition w anyone. Ok spoke w him an here we go:
it was 6.5lb w 34* which made 960. I was told it would make close to 1000 w some more boost prob have to splash the fuel i guess.. then he took boost out of it made it 5.5lbs at 34* made 909. that is where he did all final testing w that boost. then took alittle timing out an thats what he wants me to keep. Oh and compression is over 9 .Now all you engine guys out there i dont know what to say i guess i made all these #s up. Now i only wish it was warm enough to go prop test.
Have a great holiday everyone.

Ron

Bawana

Thanks Mild Thunder, I didn't realize that your static compression was at 9:1, what gas do you run? Have you been on vacation? Haven't seen you on here for a bit.

mike tkach

iTrader: (3)

he has been on a work vacation,lol.his new job including drive time makes for a 11 hour day.he burns 93 oct fuel and i believe boost is about 6 lbs.his 468s make right at 800 hp.timing is 33 or 34 total.he has 3 years on these engines and they run like they did when fresh,they don,t even burn any oil.

MILD THUNDER

iTrader: (3)

Mike is right. I am a hair under 9:1 static. 6lbs of boost. 420 B&M blowers . no chillers. Twin 850 carbs. Alum dart heads . no water thermostats but have oil thermostats.

HaxbySpeed

So MT's motors make 1.71 HP per cube at 6#'s. no chiller, and a B&M blower. Zul's 540 makes 1.78 per cube at 6.5#'s with a better blower, solid roller, good heads, etc.

Where is all the controversy coming from? Because of .07hp per cube? Seems reasonable to me.