Yup, I am the idiot checking this and watching the fuel in the bowls (glass sights) while on dyno during full swing.

Wanna laugh ? I'd always cover my nuts with my hand(s). Like that would protect me. Hah !

Haven't looked to dyno issue post yet but if the dyno was correct at making little to no power from 5,500 to 6,000 I don't see how it would make a difference with the flame arrestors and hatch crack but I've witnessed in boat scinerio first hand recently.

[ATTACH=CONFIG]559649[/ATTACH]Do it already! Hah!!

I saw mike tkach do that, on a 1300HP build. I had to walk away, I couldn't watch. lol

I don't even know if this titanium cup would help, but its better than your hand! ha

Also did you ever try different carbs on dyno? even any other 4150?

but it saved it from burn down and i,m married so i don,t need my nuts anyway,lol.

you sure did. But next time, lets bring a go pro camera !

That was real world data right there though!

Doh !

I have gotten reverse spelled Hooker and also Kawasaki burns on my hand and arms. Fuk me those hurt !

No, you really couldn't read them, but I knew what they said unti they turned into big blisters that peeled right off.

Truth be told, if it doesn't have an ATI harmonic dampener, I get really apprehensive.

3", that's all that fits under my hatch, I did however gut them....

No, the time was not there or the parts... My Dyno session was simply to see if engines match and very little tuning...

I do believe I saw somewhere,one of the car mags did a test w/ a little 350,,dom actually worked,made power and they did have to jet down a chit ton.but it did work.

thinking plan, fix trans, I have forward still but no reverse, do not wanna run that way.... my buddy can fix in a couple days of dropping off...

go test boat, vacuum gage, also remove arrestor, hoping I can get this figured out before winter....that's the goal I think...

https://www.youtube.com/watch?v=iJNaaMJsCHM

I'd also set a baseline by running with the hatch off so if you do find a set of dominators to try you are comparing apples to apples.

I agree there! My engines have stock dampeners and that is the next thing to go. They will be replaced with ATI's.

I did that last winter. Well, not with ATI, but replaced the stockers, with Powerbond SS race balancers. One of the things that concerned me, was being that I had a external balance setup, was the weight match of the balancers. I called a few shops, including the one that balanced my rotators few years back, and they said they don't balance a damper. Some acted like I was talking crazy.

I finally found a local shop, that I never even knew existed. They do in house crank work, heck, just about everything in house. Anyways, I called the old timer, explained what I was doing, he said sure, no problem. Bring the old ones in, and the new ones, and we can certainly check them against each other. He spun them, checked them, and they were a C hair away from the old balancers. No actual work was needed. Got some fancy computer printouts of the balancing tests. Cost me 150 bucks to find that out, but, I felt better about installing them.

I didn't feel very confident spinning the stock old GM balancers to 6000+. I heard good things about the powerbond units from a few marine engine builders, and Icdedppl's 540's have had them on there for a while now, with blowers and good results. They make them in a supercharged version, with double keyways as well.

http://www.competitionproducts.com/P.../#.V-PWaTXLpwM

that's a good price to ^^^^

I thought so too. I basically wanted to ditch the 30 year old stock iron/rubber units, with a steel unit. ATI's are great balancers, but knowing that sooner or later, I'm going to outgrow these ext balanced 468's, I didn't feel like dropping 700 bucks on a pair of balancers.

At peak vacuum is -1.2 not 1.7 [ATTACH=CONFIG]559658[/ATTACH]

SB, your article you posted on the other thread, got my wheels turning this morning. In that article, the purpose was a cylinder head shootout. What I couldn't help buy notice, was the overall build.

They had a ZZ502 GM crate shortblock. WIth most of those heads, the compression ration was in the 9:1 static range. Up top, sat a holley HP 1000cfm, 4150 carb. Camshaft, was a 245/250, 650 lift, 112 LSA solid roller. Not a very agressive lobe cam.

Aside from the fact, this 9:1 502, made more power than Tim's 9.5:1 540 with afr 325's and CNC chambers, I was looking more at the powerband.

Tims engines made PEAK TQ, at 4400RPM. Peak HP, at 5800RPM. From 5400RPM, to 5800RPM, tim gained, 11hp. 618 to 629.

This 502, made peak torque around 5200RPM, and peak HP, around 6200RPM. From 5400, to 5800 rpm, this engine gained 35HP.

Tim's cam is a 241/246 duration, in a 540 CI. That engine, while a solid, was 245/250 duration, in a 502CI

Anyhow, that engine in the article, seemed to make peak HP, 1000RPM over its peak torque rpm. Tims engine, making peak torque at 4400RPM, also seemed to start dying off 1000RPM over its peak torque, around 5400RPM. Do we still think smaller cams is the magic bullet in tims engine?

Sweet. So I'll make more hp than some 540s with my 502s. Digging that article.

Mike I had one fly apart on my 73 z downstate. Was very thankful no one was injured as it was one of those late Saturday afternoons with the boys stacked up on the street corner to see who could get the most hang time. I got cut short and damper ended up going through lower front fender and stuck into an oak tree. You may have noticed I have ATI now on any build. After that I've always been leary at more power when dynoing. Going down this fall to help him get caught up. You should come help.

Okay, this needs to be noted again, as I mentioned on that thread, look at the power differences....not the power #'s by themselves tocompare against a motor dyno'd somewhere else.

Back then, Westec's dyno read real high. This is not a jab or a fight in this thread. It did,and it is fact.


Edit in: Not sure of dyno room atmospheric conditions on FF's run, but it is only around 3% correction factor. Very rare to see any factor this low on the million dynosheets I've seen on the net.

When comparing cams the rule of thumb i have always followed is a solid roller will be 10 degrees bigger on paper compared to a hyd roller ie that solid at 245/250 would compare to a hyd at 235/240 to be sewhat equal

It depends on the lobe profile. Not all solids are the same. A .020 lash setup, can be different than a tight lash. 10 degrees seems a bit high @ .050 .

Was just going to type this in,and I agree. Top of my head is closer to 8 degrees (splitting hairs, I know) if you average most out.

However, still near impossible to do a direct comparison, but even accounting for this a normal solid roller (after lash) that is as similar to that hyd roller as you can try to get, will usually still be 20+hp better and carry the rpm better of course.

back in my drag boat days one of the guys had a stock gm dampener explode right at the finish line,the broken parts blew through the bottom of the boat and it sunk in short order.i will say that the engine was at 7500 rpm when it happened but will also say no stock bb dampener should see 6000 rpm,espically an old one with cracks in the material the devider is made of.also want to say that ati is not the only sfi dampener on the market and their are a lot of good ones for less money.

What exactly determines correction factor?

Everything, but seems mostly penis size. LOL.

When running simulations or performance trends dyno simulator a 4.0 stroke motor shows a internal friction loss of 270ish hp at 6500 where a 540 shows 320 ish due to higher piston speed, w identicsl heads, cam, etc the 540 has a tq advantage in mid range and the 502 shows a slight hp advstage above 6000, ie if the piston speed w 4.25 stroke ABOVE 6000 has a 35 hp advantage but 50 more hp of parasitic loss measured hp would be 15 less than the 502, ill take the extra power at 5000/5500 any day from the 540 though!

atmospheric conditions,

I have a camshaft design program. It seems to work very well against, what some cams/builds have seen on the dyno as far as powerband goes.

Anyone willing to guess, what change in .050 duration, there would be on a hyd roller, between a 502ci, and a 540ci, looking to make maximum power at 6000 engine speed, if all other things were equal?

Temperature, Humidity, Accessories and What number the builder needs to make, to meet customer expectations and agreement........lol.

Near 10* ? Maybe 12* ?

Baro, air temp, station press, humidity,altitude etc. To see 3% you need to have almost perfect air, ie low humidity and around 60 degrees intake air IF using j607, i cant see ypur dyno sheets on my ph but which cf was used, sae1349 yields numbers 3.9% lower than j607 . Crockett, mer, Eddie young, gellner etc all use j607, i use j607 on my dyno, a merc engine is dynoed at 1349 so if it makes 500 hp at merc and you put it on my dyno it should make 520 corrected. If your motor dynoed at 630 hp w 1349 if you put it on any dyno using j607 it would magically make 3.9% more, ie about 655hp, if it dynoed at j607 and you redynoed it somewhere using 1349 it would LOSE 25 hp and show 605hp, IF you were comparing it or ANY motor dynoed at j607 to merc hp numbers take 3.9% off to make comparison e+ual, only useful for comparing dyno to dyno though. 99% of shops use old j607 cf because their nbers would look low in comparison to other shops if they used 1349, fwiw, Smitty

^^^^Yes^^^

Here's the difference

SAE J607 standard of a 60°F day with 0% humidity and a barometric pressure of 29.92 in-Hg

SAE J1349 standard of 77°F day with 0% humidity and a barometric pressure of 29.234 in-Hg

I entered the parameters, for 5500RPM max. I don't want to hear the backlash from the 6000RPM durations, and how someone built a 632ci with a 224/234 cam and it rev'd to 7200.

454=229/234
502=233/240
540=243/252
572=252/263
598=253/266

7 to 10?