Well it just gives out a calculated number based on torque and rpm
So….more header talk….this had me scratching my head
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Rat Bastid
Dunamis Metron
Dyno’s only measure torque and RPM. Horsepower is calculated from those numbers. It’s accurate.
The other thing dyno’s do not do, at least in the full definition of the sense of the term is measure the rate of acceleration, or the change of the rate of acceleration. That’s far more important than the fact a dyno doesn’t measure horsepower.
What you are asking ANY engine in ANY form of Motorsports is to accelerate from one point to another. That’s it. The faster the engine accelerates the car, the better the ET slips or lap times.
There is at least one dyno that will measure acceleration rates and that is the Revolution Dyno. It’s not cheap. I almost had my hands on one. The second one ever built. But a fat, lying shyster screwed me out of it. That dyno will measure the rate of acceleration and the rate of change of acceleration.
You can overcome this liability of the water brake dyno by changing from the magazine standard 300 RPM/second to 600 RPM/second or even faster. That way the dyno is not holding the engine back as much as it will at slower acceleration rates. But, the byproduct of that is you WILL get a lower HP number.
I think that slow rate of test is why some things look good on a water brake dyno but don’t produce on the track and why things don’t show power on the dyno but go faster on the track. In fact, I know that’s true and I have some graphs and data to back that up.
You have to know the limits of your testing equipment. Just like the flowbench, more flow isn’t always better. You have to KNOW what you see, hear and measure and how the interrelate. Otherwise you will port for a number and kill power.
Maybe you should ask Chris Hardy how he does it. His stuff must be rpming to be winning.
Scody21
Just send it
**** the dynos now will run a full track with load / shift sim..
Rat Bastid
Dunamis Metron
Is he the only one winning? Nope. I’m saying you can’t move torque down, or even build torque below useable RPM and not give up horsepower where it counts. That’s simple science.
What you are asking me to believe (because this guy didn’t say it, you are) is that he is making more torque below peak torque and gaining horsepower in the upper rpm range. If so, he must be a god because he’d be the only one making the claim.
9secRR
Well-Known Member
Well another thread gone to ****. It started out good and now it’s a pissing match.
His quote is about his street stock engines lol, nowhere is he saying in that video, don't go bigger on the port ever.
He's is talking about short track roundy round engines which of course need a small port to keep in the torque curve.
Which don't need a big cam either
Continue with the good part.
Rat Bastid
Dunamis Metron
Right, because hysteric in his usual way won’t commit to anything but innuendo and deflection. I made my points clear and stand by them. It gets real old real fast with this guy.
Here are his words again:
Maybe you can ring him and convince him he's doing it all wrong. Everyone here knows bigger heads make more power everywhere according to the self proclaimed experts.
He's obviously thinking about more Torque.
Here is the guy who mentored him:
Jerry has set 19 new NHRA National ET and MPH records, won 14 NHRA Winston Drag Racing Series Division races, been a three-time 1/8 mile National Open Competition Champion and received 20 NHRA Low Qualifier awards. His racing peers have voted him Mechanic of the Year four times as well as Driver of the Year, and the NHRA track managers and events staff awarded his car the Best Engineered Car. Jerry has been also a four-time NHRA Winston Drag Racing Series Division Champion in Competition Eliminator, TRW Sportsmen All Stars Race Division #3 Competition Representative and NHRA Winston Drag Racing Competition Runner-Up. A crowning achievement was when Jerry was the Competition Eliminator Winner in the Federal Mogul Championship Allstar race.
I'm sure Chris Hardy knows a thing or 2 for him to say what he did.
To quote the late great Shrinker when asked about why the AFR changed when they went to a bigger header Bruce replied. "The reason for that is not that the carby has changed AFR, that it not possible unless your exhaust pipes managed to grab a spanner while you weren't looking and changed the jets"
Have a think about that for a while.
Rat Bastid
Dunamis Metron
Do you ever put anything in your own words?
I don’t need to think about that quote at all. It makes zero sense.
Once again you have no point in a thread. I’m out.
I don't need to when I can provide evidence of what I think by deferring to a higher authority on a subject. I'll let you think you know more than him about how carbs work.
Maybe start with Larew's work in "Carburetors and Carburetion" 1967.
Rat Bastid
Dunamis Metron
Yep. Like you always do, you have a quote with no context. Simple as that.
If you don’t…oh never mind.
B3422w5
Well-Known Member
NHRA North Central Division news: NHRA Lucas Oil Drag Racing Series Notes from Mid-Michigan Motorplex
pretty sure that particular record he set was with a 250 6 banger in a 71 Chevelle.
Think it ultimately went faster
pretty sure that particular record he set was with a 250 6 banger in a 71 Chevelle.
Think it ultimately went faster
Sr4440
Well-Known Member
The guy you are quoting clearly has never heard of intake reversion. As you make the exhaust more efficient, the intake reversion gets reduced/eliminated. When that happens, the incoming air does not go "backwards" through the booster because of reversion, you will now have a leaner mixture. You can "see" this happening on an engine dyno, the lbs of fuel use goes down, A/F trends leaner and the volumetric efficiency goes up.
As far as the HP "changing" with the rate of acceleration changing on a dyno pull, well it doesn't, only what is measured changes. There is a way to get actuate numbers. I wrote on this same subject on my website, if you want to read it go to http://www.cen-texenginedyno.com/ and read "Joe's BS" at the bottom of the page.
Joe
9secRR
Well-Known Member
I run a Rons toilet and I was way rich after the bigger header swap. So my question is, why is that?
Bruce knew and wrote plenty about reversion so I have to disagree with that. In fact I recall discussions with him about black up the intake and even into the carbs.
I agree that when statements are taken out of their original context, they may in part no longer be true.
When a carb is delivering a flat AFR in the power band, increases or reductions the velocity through the booster still produces the same AFR.
Of course the first part is critical for the rest to follow.
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Its a good question. I dont know that we can answer that over the internet, but I do think its worth trying to understand.
The first thing I might want to look at is the fuel logs if you have them. In other words is the AFR flat in the rpm range of interest? Make sense?
lead69
hopeless car junkie
Post number 9 touches on this, we just experienced the exact same thing in my car going from 1 5/8 to 1 7/8, had to take a bunch of jet out.
Because you lost exhaust velocity, it built a low pressure wave at or near the collector which did not get evacuated completely, it just sat there until and was partially sucked back into your intake charge.
Not enough fresh air paired with all that fuel caused rich mixture.
I believe darin Morgan and hooker headers told me that in my reading
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Rat Bastid
Dunamis Metron
I have no idea why you went rich. I can explain it with a carb but not with MFI. I’ll have to think on it but that really makes no sense.
MOPAROFFICIAL
Oogliboogli
Yep. The scavenge effect.
As was said by mattax about statements of truth becoming untrue when taken out of context , people hear "no exhaust/pipes, "straight header" "bigger be better". "High rpm need no back pressure" look at those imporks,hear the sound of torque loss..lol
Same for gasket matching exhaust ports and turning them into a trumpet at the exit where it all expands too much too soon and loses velocity aka loses scavenge/pulse.
Like a train or big rig blowing by you on the side of the road...it pulls you in its direction with its passing....nascar 'draft'. Etc.
Many versions of that vacuum.
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Rat Bastid
Dunamis Metron
There is a big difference between a water brake dyno and an inertia dyno. That’s what I was saying. One measures how fast the engine accelerates and the rate of change and the other doesn’t.
Rat Bastid
Dunamis Metron
Ac
Actually, if it goes lean with a header change you can bet the header isn’t functioning correctly.
When you change from one header to another and you have to take jet out (because it’s rich) you know the header is doing it’s job. There is a reason for that and it’s important, not only for header function but any time you do work on the induction or exhaust. Any time you have to take jet away (for the most part) you will make more power and be quicker and faster on the track.
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