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-   -   low compression 548 dyno testing has begun!! (https://www.offshoreonly.com/forums/general-q/344612-low-compression-548-dyno-testing-has-begun.html)

articfriends 03-30-2017 10:40 AM


Originally Posted by Gimme Fuel (Post 4542102)
I could come do some wiring this weekend probably. Let me know what your work schedule is.

Saturday, wife is working at church from 2 till 7, its my first day off so i will definately be at shop dynoing, especially since i see good air coming lol! Call me, we can make pulls and swap parts then maybe sort out this new install, ill even buy lunch! Going to be bolting your parts on too, bring any air ducting you might have for that tb as we have to get air to it from away from headers, maybe a old cai kit you might have or something?

Gimme Fuel 03-30-2017 10:54 AM


Originally Posted by articfriends (Post 4542104)
Saturday, wife is working at church from 2 till 7, its my first day off so i will definately be at shop dynoing, especially since i see good air coming lol! Call me, we can make pulls and swap parts then maybe sort out this new install, ill even buy lunch! Going to be bolting your parts on too, bring any air ducting you might have for that tb as we have to get air to it from away from headers, maybe a old cai kit you might have or something?

I'll see what I can dig up. I could at least grab some modeling clay and form a bell inlet around the TB opening. I also have some new 4" rigid exhaust hose that should slip right over the TB. I'll come up with something.

Saturday looks like a great day for me to come out then! Giggidy!

articfriends 03-30-2017 10:55 AM

One last thing before getting to work, so after tweaking fuel, timing making 690 ish corrected hp thru mufflers, last pull, time for fxxxxxxg glory pull w open headers, let see 700!! Nope, made same peak hp/tq within 2 or so ay peaks BUT picked up that 20 ft lbs of tq from 3000 to 4600 its been missing, doesnt do alot of good though, its not going to be in a boat w dry, unmuffled open headers

SB 03-30-2017 11:12 AM

Below is how Superflow does it (add's friction hp loss)
Issue is that they, like others, either assume 15% of engine hp is lost too friction, or they have a friction hp loss # based off of stroke.

Yeh - great right ? Said sarcastically

Superflow uses the following formula using FHp in CBHp

CBHp = (OHp + FHp) x CF – FHp
CBHp= corrected power
OHp=observed power
FHp=frictional power
CF=correction factor

cyrus77 03-30-2017 11:15 AM

Since you are running a MEFI3, I would love to see a stock Mercruiser MPI manifold on this too see the difference. Cool work.
,

SB 03-30-2017 11:23 AM


Originally Posted by cyrus77 (Post 4542116)
Since you are running a MEFI3, I would love to see a stock Mercruiser MPI manifold on this too see the difference. Cool work.
,

LOL.

http://www.snoringmouthpieceguide.co...ce-266x300.jpg

articfriends 03-30-2017 01:25 PM


Originally Posted by cyrus77 (Post 4542116)
Since you are running a MEFI3, I would love to see a stock Mercruiser MPI manifold on this too see the difference. Cool work.
,

Waste of time, I did previously have a modified mpi intake on this exact motor on this dyno, it made 630 hp with biggest bored out tb that exist, tons of port work on intake and slightly modified plenum, it made like 622 with 65 mm tb and 614 w stock. With 10 degrees less duration cam than this one on Crocketts dyno 10 years ago made about 647 w 20/w50 oil, made 655 or 657 with 5w40 synthetic but not same dyno. Same intake made 560+ hp on a .004 over 8.8 compression 502 with slightly modded 088 iron heads and 500 efi cam after extensive tuning, no accessorys, dry dyno headers at J607

articfriends 03-30-2017 01:41 PM


Originally Posted by SB (Post 4542115)
Below is how Superflow does it (add's friction hp loss)
Issue is that they, like others, either assume 15% of engine hp is lost too friction, or they have a friction hp loss # based off of stroke.

Yeh - great right ? Said sarcastically

Superflow uses the following formula using FHp in CBHp


CBHp = (OHp + FHp) x CF – FHp
CBHp= corrected power
OHp=observed power
FHp=frictional power
CF=correction factor

so a 700 hp motor at 1.05 cf has a friction factor of 5.25 hp added to cf vs observed? sounds about right compared to depac
I think the depac friction factor is slightly more generous or motor doesnt have quite 15% friction as at 2.8% CF am gaining 28 hp from CF at 663 observed when it would be 18.56 actually.
What this means to all the normal guys reading this who are scratching there heads: the higher your CF is on dyno, the less accurate your numbers are PERIOD. At one point Roccard came on here showing a 454 or 502 making 710 + hp w edelbrock 9-1 290 cc heads on 91 octane for sale, problem is he showed bsfc and lbs hr fuel used, motor used like 290 lbs per hr fuel at hp peak at .5 bsfc, he did NOT show CF used. So doing some real easy math, 290 x 2 (being bsfc was .5) is 580, thats how much hp worth of fuel he used at .5 bsfc, the numbers dont lie, so motor made 580 observed hp and was corrected 22.4 %, you would have to be dynoing in a monsoon at 5000 feet elevation to have a 22.4% CF, totally lies and BS, he quickly got ran off this board. You will ALSO notice that some very good looking dyno sheets from well known builders have been posted on OSO thru the years and you will OFTEN see BSFC and lbs per hr whited or blackened out, why, whats to hide??

bck 03-30-2017 01:42 PM

Smitty, I still have a few more to send, but did you get the emails and attachments I sent after our call a few weeks ago?

articfriends 03-30-2017 02:34 PM


Originally Posted by bck (Post 4542144)
Smitty, I still have a few more to send, but did you get the emails and attachments I sent after our call a few weeks ago?

I did, i don't have enough ink and paper in my printer to print them all out yet I'm going to forward them to my wife and have her print them at work then when I get a spare few hours I will digest off your data sorry for not getting back with you sooner


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