Anyone ever use this HP calculator
Thread Starter
Drifting
Joined: Jun 2010
Posts: 1,312
Likes: 156
From: Richmond Texas
Anyone ever use this HP calculator
https://www.gofastmath.com/Horsepowe...wer_Calculator
I'm wondering how close it will get. I entered all my data. I guessed at the peak intake flow in CFM at 28" of water: I got no clue.
This is my result.
That engine should make approximately:
453 HP @ 4755 RPM
Thinking that is a bit optimistic.
I'm wondering how close it will get. I entered all my data. I guessed at the peak intake flow in CFM at 28" of water: I got no clue.
This is my result.
That engine should make approximately:
453 HP @ 4755 RPM
Thinking that is a bit optimistic.
Old Pro Solo Guy
Joined: Dec 2017
Posts: 8,121
Likes: 4,479
From: Marlton NJ
Well it is relying on head flow data, so that must be accurate....
But on mine, it came within 10 HP of what mine dyno'd at on an engine stand (Gross HP). (It was actually 10 low).
Loose 10-20% or so for RWHP.
But on mine, it came within 10 HP of what mine dyno'd at on an engine stand (Gross HP). (It was actually 10 low).
Loose 10-20% or so for RWHP.
Safety Car
Joined: Oct 2000
Posts: 4,080
Likes: 565
From: Allen TX
Interesting... for the build I have, it shows 513hp at 5300rpm. I have not had mine on engine dyno or a chassis dyno, but I can say that the rpm is right at where mine begins to fall off. I need to get the car on a chassis dyno, but circumstances have made it difficult this spring. I don't think my engine makes 430+rwhp, though (15-20% loss). I'm guessing more like 360-380. We'll see.
Thanks for posting this.
Thanks for posting this.
Last edited by WA 2 FST; Apr 26, 2020 at 10:38 AM.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,172
From: Hermosa
It could be pretty close. I’m estimating my HP based on chassis dyno @ 440 hp. That calculator says 433 @ 5973 rpm. So I’d say it’s within at least 3% to 5%, and a couple guys here got a lot closer than that.
too many variables to really get an exact number with any calculator. Dyno is the only way to get a number, and that too can be off depending on how “happy” of a dyno it is.
too many variables to really get an exact number with any calculator. Dyno is the only way to get a number, and that too can be off depending on how “happy” of a dyno it is.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
5 Best & 5 Worst Corvette Daily Drivers
Joe Kucinski
The Headlights of Every Corvette Generation Explained
Joe Kucinski
5 Best & 5 Most Overrated Corvette Track Packages of All Time!
Joe Kucinski
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
566 HP @ 7098 RPM
6hp more than Mamo & the machinist figured.
I agree VE has plenty to do with it among other things interesting anyways
6hp more than Mamo & the machinist figured.
I agree VE has plenty to do with it among other things interesting anyways
Last edited by cv67; Apr 26, 2020 at 10:08 PM.
Safety Car
Joined: May 2004
Posts: 4,366
Likes: 1,589
From: los altos hills california
Built my motor according to an article in Chevy High Performance (November 1999) for a "Thumper 383". A so-called "hot street engine used as a daily driver". 411 lb-ft / 431 HP @ 5500 RPM. Put about 10 years on the motor. SCAT rotating components, Pro Aluminum Lightning heads, Crower cam. Never dyno'd it, but it pulled really well all those years auto crossing. It is now sitting under my work bench and probably would run just as well as when I pulled it. This calculator was on the money as far as predictions go, as I plugged in all the exact #'s from my build. 430 HP @ 5391 RPM. Feels about right as I also know what more HP and torque feels like in my car. The only bit of info not asked for was the carb, which was a 650 CFM Holley double pumper. I could tell it was running out of flow at 6000, but I have over carbureted in the past and this got me by. Would be nice to get a torque estimate!
Thanks ZAKsPop, that kills Sunday morning, now what?
Thanks ZAKsPop, that kills Sunday morning, now what?
Safety Car
Joined: May 2004
Posts: 4,366
Likes: 1,589
From: los altos hills california
I will mention that the calculator asks for the type of intake manifold being used. I would assume there's a tweak for that. You could run a parametric study by selecting types and see if it agrees with your estimates. Or not!
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I'd be a little disappointed if this is all I made. That engine should make approximately:
586 HP @ 6630 RPM Because the choice of flat or roller doesn't talk about racing solid roller with .685 lift intake or carb cfm. The RPM is about right
Last edited by gkull; Apr 26, 2020 at 09:21 PM.
Thread Starter
Drifting
Joined: Jun 2010
Posts: 1,312
Likes: 156
From: Richmond Texas
Well, after doing all the math my engine has only an @8.5:1 compression ratio "336781 heads with flat top pistons. 30 over 454". I wasn't expecting over 400 hp. The engine felt good before it flattened a few lobes. It is rebuilt and ready to go back in. This time with a roller cam.