Jason, was that thing in the .43 range on top too? How high does he spin that?

http://www.compfuelsystems.com/
Hes old school, wealth of knowledge, you need to come over some time and meet him.
On another thread, mild thunder made statement that he wouldnt pay a premium price for a all out one of a kind custom carb , even if there was a guaranteed 20 hp (and theres no guarantee). Myself, as a BLOWER motor guy would completely agree. If i have a boosted motor, its making 1050hp on 92, i put some 93 in, bump timing one degree and make 1080, or i throw my full kill pulleys on, turn fuel press to efi up 3 lbs. You will NOTICE (and i do it myself), when blower motor guys talk about hp, for most part its"my motor makes 900 hp, makes, 1050 hp, makes 1100 hp". When NA guys talk about hp its, my motor makes 637.8 or 691 or what ever!
As a NA guy, HOWEVER, people fight, scratch and kill to find tiny ,incremental gains. This motor is sitting on dyno right now, when i walked away from it the other day it was making 691 corrected hp. Aside from the tb spacer im going to try today, unless i change cam, compression, something major its about maxed out. If a guy said he could rework my tb and drop it back on here and get me 705 or 710, id be all for it!!

Its both really, we all hear "you dont tune for bsfcs". No, you DONT, BUT, I will say THIS, having unlimited dyno time WITH a bsfc/flow meter sitting here I have started to see a few things more CLEARLY. Ok, sure, we dont tune for bsfcs, its strictly a measurement of fuel used and shows how efficient motor really is. Not completely true, mostly true but not completely.
Started out with this dyno project tuning for max hp, until im done and motors going in boat, i dont really care about "fuel safe" afrs, i strictly am tunig for max hp. Think like a drag tune. So I mentioned this previously, motor was tuned in, afrs at wot might be 13.6 or 14, its just a 10 second dyno pull, wont hurt anything. Soooo, we have bsfcs in lower to mid .5s, ooh, wow, motors somewhat efficient . Now lets say we bolt Tims 1050 QF carb on, AS JETTED, afrs are mid 12's (10%richer), wot bsfc climbs to .67 from .57, using 10% more fuel. Damn, motors a piece of inefficient crap right, carbs JUNK, bsfcs just went in trash can. NO, we just drove them up by adding jet to have target afrs that wont melt pistons and drop valve heads. So, NOW to be fair in hp comparison, we start adding jet to norms carb to get SAME target afrs. Now, bsfc with HIS carb goes up to .62, pos needs to go in trash too, its a pig right, NO, we just tuned afrs safe. NOW, lets say i bolt efi on, making pulls, bsfc is .70, motors chuggy, afrs look like crap, YES, i know at that point they need to come down, when i start seeing something in the .6 range on top i know im getting close to before.
Now, lets go BACK to the two carbs, lets say bsfc with carb A is .67 and AFR is at 12.5, with carb B bsfc is .62 at same exact AFRS's, NOW we are seeing a difference in efficiency, something about carb b atomizes the fuel more effectively OR it makes measurably more hp with same amount of fuel for other reasons which says we are making x #of hp per lb of fuel, now we are looking at bsfc's at true efficency

For what it's worth (may not really add anything to what's being learned here) here's a sheet from my 512.
I have a Dale Cubic custom 4150 that wet flows around 870cfm.

When we were on the dyno I called Dale and one of his first questions was "what are the bsfc numbers"? We took several looks at the spark plugs and adjusted the timing and crankcase vacuum, but that was it.

We decided to leave the carb tune be and fine tune it once in the boat with the dual channel O2 sensors hooked up.
http://i205.photobucket.com/albums/b...ps0mgow9uv.jpg

Perfect example, your at .51 bsfc at 13.5 at 6300, lets say you decide your target afr in boat should be 12.5 at wot so you add 8% more fuel, your new afr should be about 12.5 and your bsfc would change theoretically 8% to .55, if you went to 12.15 at wot, would be .56/.57 BUT lets ALSO say going to 12.15 from 13.5 kills 5%hp, approx 38, BUT your still using the same 292 lbs per hr PLUS the extra 10% you added, (another 29). Now we take that new minus 38 hp into acct on the bsfc and we now jump from that .57 to just under .600 (remember we lost 5%hp from adding that extra fuel).

So going to start more testing in a little while, disappointing news from norm on rons throttle body and adapter, its 102 mm, not 105. He flowed throttle body at around 900 cfm, not 1500 or 2000 we were led to believe it was. After some grinding and wide open adjustments he got it to flow 1070. Once he bolted it on 4500 90 degree adapter flow dropped under 900 cfm. After doing some clean up on adapter he got flow just over 900. Still going to test it, any guesses as what it will do to hp and tq?

and mefiburn should change the base tune they give out so this doesn't happen to others out there.

also comes down to how accurately your measuring fuel flow.just another measurement that can be fcked w/ to say I have the most efficient porting,,even better than a nascar team.

Been reading up on how the drag guys tune. Doesn't sound particularly applicable to a boat.

The real obsessive NA looking for every HP tune lean and start their Dyno pulls above peak torque to avoid the chance of detonation. They start on C16 then once the tune is close switch to C45 which is only 100 octane!

Their tunes are banking on never being at WOT at or below peak torque!

I actually never started w a tune that came directly from mefiburn, i have tuned stuff on the water that had dtarting tunes from other people that i have kept final copys of afterwards, i have unlocked stock 502, 500efi tunes, i have unlocked ram jet 502 tunes, copys of tunes of my stuff that got dynoed at crocketts etc.
Made some more incremental progress on dyno today too, once i digest and review the data i will post results, i will say the 1"spacer under TB had small positive gains everwhere.

So another full day of dyno testing yesterday. Warmed up motor, base lined at 684 corrected hp for day. Theres not much temp/baro compensating turned on in efi program right now so not unusual to see power change 1% day to day.
So we made global changes to fuel pressure, simply wanted to see IF power output changed w more or less, if it DID our tune was still not perfect. This applys to ANY basic efi too, if giving it more or less fuel changes it measurably then yourbnot there yet!
So, we go from 42.5 to 47.5, motor losses another 10-15 ft lbs tq from 2800 to 4000, picks up 5 ft lbs at 4200, 11 at 4400, 17 at 4600 , similar gains of 3 to 10 hp all the way to peak. NOW, some of it only got us to barely beatour good numbets from last dyno session, keep in mind again most the temp/baro compensating stuff in this tune isnt set up yet. So, we reduce fuel pressure down to 37.5, pull, motor cleans up from 2800 to 4000, definately is down from there up so i cut pull short. So i make some quick changes to tune taking fuel out down low and adding 3-4% in the midrange, 1% on top, ive previuosly added dubtracted that 1% and hp bounces between 684 to 691 corrected depending on day so your really just chasing a ghost at thst point.

So after making changes make pulls to verify, DEFINATELY picked up so.e of that missing low tq vs best carbed pull, definately fattened up tq peak range, saw 686 hp peak.
So now we add another 1" spacer, stuff gets real interesting, we already have a phenolic 1"4 hole inder tb, now we have THAT and 1" open.
Make pulls, motor picks up EVERYWHERE, 5ftlbs 3400, 7 at 3800, 2 at 4400, 7 at 4800, 5 at 5400, hp peak really widens up, +7 at 5800, 10 at 6000, make 690 to 692 from 6300 to 6600. Afrs: they barely change. Tq dip at 4000, does NOT change.
So, WITH some fuel tweaking, then adding a second spacer we have now matched or beat the best carbed muffled vs muffled pulls. Im surprised w the extra spacer motor lost nothing anywhere, it only gained!

So now we make a glory pull, no mufflers, just open headers. I did this last time too, it fattened up tq but hp went knowhere. Not this time, w open headers we hit 695 hp at 6500, 705 at 6700. The tq from 4000 to 4600 went up 25 to 30 ft lbs, the spacer seemed to really help with open headers but pretty irrelevant since running w the mufflers is much closer to what boat exhaust would be like

So now, we move on to rons tb. 102 mm chinese copy of a fast, mounted on a elbow. We thought it was 105, its not, when norm tested it it flowed sub 900 cfm, after grinding and tweaking still did not break 1100, no where near the 1600 or "2000"we thought it flowed although keep this in mind too, its a single mono blade, very few flow benches including norms can flow a 1000 or 1500 cfm at normal pressure, you would need a 10 or 15 hp air pump on the bench. So when you do something this big it has to be done at a reduced air pressure then calculated back so you can start losing accuracy.

good luck,,we'll be waiting on the results.
btw,,good job

So ching chong tb on, added the 1"spacer right off the bat, make pulls. AFTER changing fuel to get afrs right it
Pretty much whacked 0 to 20 ft lbs of tq and 14 to 26 hp off from 5400 up, at 6500 hp was down 48 before tuning and 23 after tuning. At 6000 was down 20 even after tuning. No where did we pick up tq from its smaller size.
Torque dip, with its crappy compression and huge cam, this motor has a 35 to 40 ft lb tq dip around 4000 rpms, with carb, w 4500 tb, w and wo spacers and even with the much smaller monoblade.

I bet your neighbors luv the open header pulls............lol.........I would....:D

So ching chong tb on, added the 1"spacer right off the bat, make pulls. AFTER changing fuel to get afrs right it
Pretty much whacked 0 to 20 ft lbs of tq and 14 to 26 hp off from 5400 up, at 6500 hp was down 48 before tuning and 23 after tuning. At 6000 was down 20 even after tuning. No where did we pick up tq from its smaller size. Tq at peak was down from lows 630s to 610 ish, a solid 20. I sorta thought somewhere the motor would pickup some tq. Another strange thing is we monitored map pressure/vacuum st wot, i never saw map drop below 98.8 at wot which tells you its not really a restriction BUT if that was so why the hp drop then? Previously when dynoing 502 mag i saw all kinds of map readings down between 92.5 and mid 90s when trying restrictive tb's, fallflame arrestors etc.
Torque dip, with its crappy compression and huge cam, this motor has a 35 to 40 ft lb tq dip around 4000 rpms, with carb, w 4500 tb, w and wo spacers and even with the much smaller monoblade.

Luckily we are zoned light commercial/ag and they are 1/2 mile away. I try to only make 1 open header pull a day though as it carrys along ways! Last time i dynoed with mufflers on Norm who lives 4 and 1/2 miles away called me up and said i could hear you off in the distance!

What do you run for dyno muffler? Thanks

I think there is a picture on post #133

A pair of 5" inlet cheap gibson boat mufflers, they knock noise down pretty good and they dont seem to hurt hp too bad although the torque picked up pretty good with them off

Thanks for posting the picture like to see what other people use.

I used to have ggbs on my baja, the bolt and clamp weren't tight enough so one blew off in 100 feet of water at 85 mph so i needed mufflers, ggb wasn't answering there phone so i couldnt get another one so i bought these for 400$. Baja ran 99.5 with and without them, when i sold it i took blower motor out and sold the stainless marine 3s. Had these laying around , norm had some gigantic semi mufflers and flex tube we had to drag out and stick on everytime we dynoed. One day i pulled without his and picked up 20hp on my 502 i was dynoing. I stuck these on the 5" pipes coming off the headers and motor only lost 2 or 3 hp and noise was tolerable so i been running them ever since on the dyno.

Rons tb, i would only consider running one of these if you were using a centrifugal and it made plumbing easier, cost too much hp otherwise.

I thought he had the same one we tried and did not work, but one we tried was a std 4150 style, 3 blade from accel, in testing on LS stuff what you saw with this about right, the victor style intake and 4150TB kicked this ass everytime...

He did, he bought this to try as hes considering using these on his 502

So youre saying the ching chang chit are liars about what their T/B flows?

Ya don't say? LMAO

I didnt buy it, Gimmefuel on here did to test, its a poor copy of the fast which doesn't claim to flow any insane amount to start with!

It was cheap enough to buy for a dyno test. Was considering it for my rebuilds since I was considering procharger them at a later point. Don't know until you try! This one never had flow claims made with it. Hard to find flow data on any brand. Wilson's 105 mm claimed around 1500 cfm. I figured this at a 102 mm should at least break 1000 cfm easily. Apparently not so much! Might work good on a much lesser engine, just not in this 6700 rpm 548 haha! When I do my rebuilds next winter, we will dyno them at Articfriends place. Probably​ slap it on for squits and giggles since I own it already. We also have the 2200 dominator throttle body as well. I am planning 509's staying at or below 6000 rpm with much less cam than this motor we tested.

In research, whether data is good or bad, it is still data and tells a story!

I want to see a dyno video!

I'll get it posted! Give me a bit.

https://youtu.be/HIQyuQC0Ca8

This is first pull with the 102mm monoblade throttle body.

Open header glory pull with 1" open spacer, 1" blended spacer, and 2200 cfm dominator throttle body.

https://youtu.be/Oaefqzb8ml8

Outside cold idle with mufflers.

https://youtu.be/vmE8Zr1wrOU

Ive videoed before and the computer screen looks like it blinking when recording, you dont see it w your eyes but dhows on camera!

The refresh (screen) rate and camera video frame rate are similar or a multiple of each other (aliased). You are actually seeing a picture of the screen refresh. Just like a strobe light works when setting timing.

Thats sorta what i was thinking too, i have all new data aquisition thats going on w flat screen, windows, usb, mouse, color graphs and overlays etc. Done dynoing till its in place, got a new hp computer, monitor, ordered a regulated power supply to run 02s etc, still waiting on a few things to show up

Bobl has a "muffler box" for his dyno.. Exhaust noise is almost non existent.

Kindof spooky tho' hearing every noise an engine makes.. :fear:


http://i130.photobucket.com/albums/p...pspx11ljxs.jpg

Thats really cool, wonder if it has chambers or baffles in it, looks like a GREAT way to test wet exhaust too, i have to assume it has some kind of sump in bottom to colkect water then pump it back to supply tank? Mark rinda told me to bury a septic tank w sump pump and dump water into it but i poured ALOT of new concrete before getting dyno and not going to tear it out. So far i spent 8000 putting a new well in (needed one anyways) , 2000+ on 8 02 sensor system, then bought regulated power supply to batterys, mercruiser cannon plug harness, 3000 on data aquisition, regulated power supply to run it, computer, flat screen, sensors etc. Next purchase will be ducted air supply to push heat down and away from exhaust then if it starts making money will build a addition and cell on side of building, wet exhaust recovery tank and if brake ever goes bad buy bigger brake (everything elses just about is new)