Trumpet height
- Thread starter Fatal Attraction
- Start date
Ron, if you are still intent on useing IDFs, I found some mods that worked on the air horns (trumpets) that improved stand off, Frank
Peter Delaney
GT40s Supporter
Bill, I am going to stick my neck out on the chopping block here !
My (probably naive) understanding is that as a general rule & all other things being equal (there's a dumb phrase I remember from Economics!), short trumpets = higher hp, less low-down torque & long trumpets = lower hp, more low-down torque.
The big plenum & long intakes on 90's Vette engines are probably responsible for more whiplash injuries off the lights than rear-enders !
However, with bucket loads of both hp & torque on most tweaked 8-stack setups, the differences would be hard to pick on the road. A 5hp diff could easily be wiped out by turning on the A/C & rad fan !
For road drivers like me, it probably comes down to aesthetics, what came with the kit, and what will fit !
Kind Regards,
Peter D.
My (probably naive) understanding is that as a general rule & all other things being equal (there's a dumb phrase I remember from Economics!), short trumpets = higher hp, less low-down torque & long trumpets = lower hp, more low-down torque.
The big plenum & long intakes on 90's Vette engines are probably responsible for more whiplash injuries off the lights than rear-enders !
However, with bucket loads of both hp & torque on most tweaked 8-stack setups, the differences would be hard to pick on the road. A 5hp diff could easily be wiped out by turning on the A/C & rad fan !
For road drivers like me, it probably comes down to aesthetics, what came with the kit, and what will fit !
Kind Regards,
Peter D.
Must be a lawn mower engine with only 147 ft-lbs of torque at 8000 RPM.
JimmyMac
Lifetime Supporter
Gents,
The graph is interesting, but the minor deviation shown above 6000rpm does not phase me personally as I will not be pushing my own block above 6k for long, even though I have a solid four bolt mains.
Why mess around with the low impact changes to air horn volumetric flow when we should really pay more attention to getting maximum efficiency from a good head set up and eliminating power loss through front end belt driven systems ?.
The original Weber horns did well enough at Le Mans so I'm afraid for me it's "get back to basics", unless you think that an inch or two on air horn length really counts.
Are we possibly talking about another one of those High Street status symbols ?. If so, please count me in !.
The graph is interesting, but the minor deviation shown above 6000rpm does not phase me personally as I will not be pushing my own block above 6k for long, even though I have a solid four bolt mains.
Why mess around with the low impact changes to air horn volumetric flow when we should really pay more attention to getting maximum efficiency from a good head set up and eliminating power loss through front end belt driven systems ?.
The original Weber horns did well enough at Le Mans so I'm afraid for me it's "get back to basics", unless you think that an inch or two on air horn length really counts.
Are we possibly talking about another one of those High Street status symbols ?. If so, please count me in !.
Howard Jones
Supporter
Adam, I'm sure you noted the "SAE Corrected" note. Might this have something to do with it? The other thing is how flat the HP curve is above 6K. Could this data have come from computer modeling software? Hummmm.... at any rate the shorter air horns look better IMHO. And thats what they are good for on a street driven car anyway... looks.
Howard Jones
Supporter
ah... that should have been flat above 7000RPMS. This goes to show you how narrow my focus is on all things GT40. I never considered it wasn't a SBF. At about 1.5hp per inch it looks something like 2.2 liter. Thats quite a lot of power for that small a NA motor. Maybe a dohv V6 or it could be a old ford cosworth alantic motor, I think they made about this much power, or some other 4 banger race motor.
Stack height would be dependant on what the motor was being tuned for, track, rev range, needed torque curve, power curve, engine size and layout, number of valves, cam layout etc, etc,. Real short would be 2 inchs and real long would on the order of 10 inchs. Pictures of drag race normally aperated V8s look like about 8 inchs, I have a really good picture of a f alantic car with webers on a 4 banger ford with stacks that look like about 3 inches and the orginal GT40 SBFs look like about 2 inches. Go figure.
Stack height would be dependant on what the motor was being tuned for, track, rev range, needed torque curve, power curve, engine size and layout, number of valves, cam layout etc, etc,. Real short would be 2 inchs and real long would on the order of 10 inchs. Pictures of drag race normally aperated V8s look like about 8 inchs, I have a really good picture of a f alantic car with webers on a 4 banger ford with stacks that look like about 3 inches and the orginal GT40 SBFs look like about 2 inches. Go figure.
Not that I want to pump my own material, but has everyone seen this earlier thread?
http://www.gt40s.com/ubbthreads/showflat.php?Cat=&Board=UBB6&Number=27165&page=0&view=collapsed&sb=7&o=&fpart=1
We've been there, done that. /ubbthreads/images/graemlins/cool.gif
http://www.gt40s.com/ubbthreads/showflat.php?Cat=&Board=UBB6&Number=27165&page=0&view=collapsed&sb=7&o=&fpart=1
We've been there, done that. /ubbthreads/images/graemlins/cool.gif
