You have to consider that the pressure at X speed is in PSI (pounds per square inch). In the case of your VRod, you must multiply that by the square inches of surface area it is pushing against. That then is the total force pushing against you.
Chris Karamesines (1 Viewer)
- Thread starter JFat
- Start date
You don't lose horsepower from a hoodscoop. You gain frontal area that you must overcome. The question is, can you gain more power with the increase in airflow to the engine from a hoodscoop (injector) than the power it takes to overcome the aero drag from adding the hoodscoop (injector) in the first place?
Well I believe that’s kind of like the way it takes something like 1000 HP to run the blower on a fuel motor, in the end you’re netting way more than if you didn’t have it. And IMO, while the FC injector wasn’t ideal, I don’t think that’s what kept the Greek from making a good run. I’m sure Head was hoping to establish a baseline for Chris.
ironpony
Nitro Member
- Joined
- Apr 1, 2016
- Messages
- 1,832
- Age
- 63
I had a conversation with WJ one time about the hood scoop situation, I asked this exact question and his answer was it was detrimental BUT they had to have it because the carbs were so high they were actually in the scoop itself.
Cliff
Nitro Member
- Joined
- Feb 15, 2017
- Messages
- 5,614
- Age
- 78
- Location
- Phoenix, AZ
So why do some cars with carbs have a "backwards" scoop? IE: the air inlet is at the base of the windshield. Have seen a lot of cars like that & they seem to run good. I don't know if that would work with a MMPS, for example, but just interesting to me the different designs and that they all seem to work.
- Joined
- Apr 3, 2009
- Messages
- 2,601
- Age
- 70
- Location
- Wilburn, Arkansas
I’ve always heard it’s because there is a high pressure area at the base of the windshield.
Cliff
Nitro Member
- Joined
- Feb 15, 2017
- Messages
- 5,614
- Age
- 78
- Location
- Phoenix, AZ
Thanks Ted. Makes sense to me.
none
Nitro Member
- Joined
- Jul 11, 2006
- Messages
- 2,688
- Age
- 61
- Location
- Tucson, AZ.
When I was living in the Pro Stock world we figured the scoop was about negative 50 aero HP. In top speed terms that's about 1-1.5 MPH. But we also showed a positive pressure in the scoop stating at about 140 mph (500' or so on the track) and it paid for itself so to speak. Jim Yates showed up with a different style scoop, and it was a much smaller opening which increased the air velocity while also minimizing the drag.
And the base of the windshield is a high pressure area, that why cowl induction hoods work, That's where NASCAR cars get the air from as well.
Back to the Greek, they weren't trying to run 325 MPH, so while the short injector wasn't ideal, it also wasn't the reason that they never made a clean run.
Alan
And the base of the windshield is a high pressure area, that why cowl induction hoods work, That's where NASCAR cars get the air from as well.
Back to the Greek, they weren't trying to run 325 MPH, so while the short injector wasn't ideal, it also wasn't the reason that they never made a clean run.
Alan
Cliff
Nitro Member
- Joined
- Feb 15, 2017
- Messages
- 5,614
- Age
- 78
- Location
- Phoenix, AZ
Pro Stock also had different shapes for the opening, depending on conditions. If I remember right, round opening was good conditions and it went from there. Also, they would put those little L shaped brackets inside the scoop, that would cause the air to tumble as it went thru the scoop and go into the carbs faster. There was a lot of research done on that as well as the scoops. How effective are the current P/S "scoops" / openings?
I take away two things from this. Interesting discussion but hd never got passed 200 feet so its hard to reach a good conclusion. Two, a near 90 yo man can and is still driving a 300 mph top fuel car with an acceptable degree of competence. The Greek is still one bad ass dude!
Bob K.
Nitro Member
- Joined
- Oct 22, 2006
- Messages
- 304
- Age
- 81
- Location
- LAS VEGAS, NV
Yes sir I realize that, but as they are running over 100 in around one second having the scoop that low the air flow is severely disrupted being behind the roll cage. That was just my observation. I have been hoping Chris would get some help for a long time. I have been on a crew of a top fuel car a few years ago. I remember one year at Sonoma back in the '90s when the Greek was low on Friday night at 4.67. I would sure like to see Chris run a 3.80 at around 320 mph before he hangs it up. For a man his age to pilot a Top Fuel car is amazing. I'm only 75, started racing in 1961 and I know I couldn't do it now. Only because I have a broken floating rib and couldn't take the G forces. I did start licensing on a Factory Super Stock 5 years ago with 8.80 runs, those things run the 1/8th even harder than my nitro dragster did in the early sixties. My last race car was an old Thunderbolt Ford that I just enjoyed running low 10s. I have made a lot of friends in drag racing, a lot of them gone now but I still keep up with the technology of all the classes.
