DynoTime for the 461 ..
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Joined: Jan 2000
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From: Corsicana, Tx
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Re: DynoTime for the 461 .. (Doug Brandon)
See Doug? I told you it was a good one!!
I had told Doug that the cam peaked at around 5850 rpm in my 427, and I figured around 5500 in a 460. Pretty close huh?
What I liked about that cam, was that it has great street manners, sounds good, and is ALWAYS ready to pull any time! On the chassis dyno, the difference in HP between 5850 and 7000 rpm was only 6 RWHP. That makes for an unbelievably broad powerband that is great on the street. It never had to "get up on the cam" so to speak. If you wanted to shortshift it...fine....if you wanted to run it out the back door to 7000 rpm....fine...it didn't matter.
I've played with many many cams over the years and I've found a few that don't look that killer on paper, but in reality just flat work! This is one of them. Sure a bigger cam will make more power, but there are tradeoffs in driveability and durability. This one is prety good all the way around.
Could a hyd. make similar power? Sure it could....but will it want to rev over 6000-6500 in a bigblock? Doubtful for very long. They have heavy valvetrains as compared to a small block. To get max performance out of a car, you need to be able to rev it past peak HP by a few hundred rpm. And if the power curve doesn't drop too fast, it will feel like it just pulls forever. That gets you down the road well.
Hyd's are for pickup trucks IMHO! There's just no reason for them on a serious motor. The only thing they can do well is keep things quiet. But by the time you use anti-pump up lifters, zero lash them etc to get them to rev, they are noisy AND make less power. Why give up the performance edge of being able to use a more aggressive cam AND have better manners?
Rectangular ports will for sure make the 'ole dyno needle go farther, but depending on gearing and use, the ovals can often get a motor of this size down the road much quicker. Might need some traction help! I've used rectangulars to kill bottom end and move powerband upwards on street cars, but you have to have parts that can use them and gearing to let it fly.
The heads on this motor must flow pretty darn well. Congratulations on building a killer little street toy. You're going to have fun!!
JIM
I had told Doug that the cam peaked at around 5850 rpm in my 427, and I figured around 5500 in a 460. Pretty close huh?
What I liked about that cam, was that it has great street manners, sounds good, and is ALWAYS ready to pull any time! On the chassis dyno, the difference in HP between 5850 and 7000 rpm was only 6 RWHP. That makes for an unbelievably broad powerband that is great on the street. It never had to "get up on the cam" so to speak. If you wanted to shortshift it...fine....if you wanted to run it out the back door to 7000 rpm....fine...it didn't matter.
I've played with many many cams over the years and I've found a few that don't look that killer on paper, but in reality just flat work! This is one of them. Sure a bigger cam will make more power, but there are tradeoffs in driveability and durability. This one is prety good all the way around.
Could a hyd. make similar power? Sure it could....but will it want to rev over 6000-6500 in a bigblock? Doubtful for very long. They have heavy valvetrains as compared to a small block. To get max performance out of a car, you need to be able to rev it past peak HP by a few hundred rpm. And if the power curve doesn't drop too fast, it will feel like it just pulls forever. That gets you down the road well.
Hyd's are for pickup trucks IMHO! There's just no reason for them on a serious motor. The only thing they can do well is keep things quiet. But by the time you use anti-pump up lifters, zero lash them etc to get them to rev, they are noisy AND make less power. Why give up the performance edge of being able to use a more aggressive cam AND have better manners?
Rectangular ports will for sure make the 'ole dyno needle go farther, but depending on gearing and use, the ovals can often get a motor of this size down the road much quicker. Might need some traction help! I've used rectangulars to kill bottom end and move powerband upwards on street cars, but you have to have parts that can use them and gearing to let it fly.
The heads on this motor must flow pretty darn well. Congratulations on building a killer little street toy. You're going to have fun!!
JIM
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Re: DynoTime for the 461 .. (427Hotrod)
That makes some good power now if you could chassis dyno it we will know the actual losses thru drivetrain, exhaust and accessories :D
Race Director
Joined: Jan 2000
Posts: 13,021
Likes: 2,264
From: Corsicana, Tx
2020 C2 of the Year - Modified Winner
2020 Corvette of the Year (performance mods)
C2 of Year Winner (performance mods) 2019
2017 C2 of Year Finalist
Re: DynoTime for the 461 .. (MotorHead)
I don't want to hi-jack thread....
But just for info...
The first version of my 540 made 732 hp on Superflow engine dyno. Open headers but it was using the belt driven water pump.
After installing in the car, with exact same setup it made 565 RWHP through 3" pipes to the rear bumper with Flowmaster 2 chamber mufflers, alt and fixed steel 7 blade flex fan just as I drove in off the street. This was on a Dynojet brand dyno.
I uncapped it and it made 615 RWHP! It really liked being able to breathe!
The fixed blade fan was removed and run with nothing at all. The best I could get was approx. less than 5 RWHP loss because of it. I had considered installing an electric one because of all the hype about fan loss, but since I never have overheating issues I decided I could afford to leave it alone.
The new version makes 825 HP, but I haven't put it on chassis dyno yet, but I would assume percentages to be similar.
There are many variables with chassis dyno comparisons. It's really hard to compare one setup to another. Things like heavy driveshafts/halfshafts/trans internals/flywheel/tires/wheels IRS in general. rear differentials, lubes etc etc all can really move things around.
Also, when you look at supercharged dyno numbers, you'll often find that actual track performance is way off what lesser HP cars do. I use MPH as a good baseline at track to get an idea what HP is. Lots of blown cars 400+ HP cars should run 120+ mph trap speeds but seem stuck in the 115 range. You also have to really look at HP curve, as there are many 10 sec cars out there with less than 400 RWHP, but unbelievably broad TQ curves.
JIM
But just for info...
The first version of my 540 made 732 hp on Superflow engine dyno. Open headers but it was using the belt driven water pump.
After installing in the car, with exact same setup it made 565 RWHP through 3" pipes to the rear bumper with Flowmaster 2 chamber mufflers, alt and fixed steel 7 blade flex fan just as I drove in off the street. This was on a Dynojet brand dyno.
I uncapped it and it made 615 RWHP! It really liked being able to breathe!
The fixed blade fan was removed and run with nothing at all. The best I could get was approx. less than 5 RWHP loss because of it. I had considered installing an electric one because of all the hype about fan loss, but since I never have overheating issues I decided I could afford to leave it alone.
The new version makes 825 HP, but I haven't put it on chassis dyno yet, but I would assume percentages to be similar.
There are many variables with chassis dyno comparisons. It's really hard to compare one setup to another. Things like heavy driveshafts/halfshafts/trans internals/flywheel/tires/wheels IRS in general. rear differentials, lubes etc etc all can really move things around.
Also, when you look at supercharged dyno numbers, you'll often find that actual track performance is way off what lesser HP cars do. I use MPH as a good baseline at track to get an idea what HP is. Lots of blown cars 400+ HP cars should run 120+ mph trap speeds but seem stuck in the 115 range. You also have to really look at HP curve, as there are many 10 sec cars out there with less than 400 RWHP, but unbelievably broad TQ curves.
JIM
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Joined: Feb 2001
Posts: 217
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From: Suwanee GA
Re: DynoTime for the 461 .. (427Hotrod)
427, I never doubted you! So, is it safe to say a 496 with similar components would peak at only 5200 rpm? I guess rect ports would fix that.
Btw, l like the time stamp on your first post.
Btw, l like the time stamp on your first post.
