What are you doing to route cool air into your intake?
Discussion
In a very crude experiment, we sealed the top vent to the the carb in attempt to see if we could develope an air ram effect and a supply of pressurised cool air......
...we couldn't! A monometer rigged up through the airflow showed no +ve pressure increase and infact showed a vacuum at points of acceleration!!
Waynes 'over cab' intake or the Vet's mamoooth scoop might get better results, but IMHO the std air intake is in a turbulant air space on the back of the canopy where you can expect negative pressure.
...we couldn't! A monometer rigged up through the airflow showed no +ve pressure increase and infact showed a vacuum at points of acceleration!!
Waynes 'over cab' intake or the Vet's mamoooth scoop might get better results, but IMHO the std air intake is in a turbulant air space on the back of the canopy where you can expect negative pressure.
I agree the roof scoop does not appear to work.
I don't watch it religiously but have see temperature of 64C/148F measured centre top on the rear bulkhead.
I'm waiting for scoops for the side grills which someone said they were developing in GF. If the grill alone does not bring the temp down higher up in the engine bay I will work on some sort of ducting to force the scooped air up into the top.
Steve
I don't watch it religiously but have see temperature of 64C/148F measured centre top on the rear bulkhead.
I'm waiting for scoops for the side grills which someone said they were developing in GF. If the grill alone does not bring the temp down higher up in the engine bay I will work on some sort of ducting to force the scooped air up into the top.
Steve
crafty said:
Pete - check the wind tunnel videos....
Oh yeah, not a lot of smoke getting into the air intake. Possibly a third of the volume that is put directly into it's path. And what speed does that look like? Our doors start to lift at 80+ and I don't fancy that bod is standing in a 120+ mph headwind even if it is directed to the centre of the car.Lets look at some of our heros...........back in a min.
Nice models... Looks like the race car air scoops open up on the front and higher on the roof than the standard GTR. Would have thought that the factory would factor this in the design, no?
That is one VERY nice black GTR in the last photo...... Any other info and what specs?? Am also thinking that black looks great (like my RS)
That is one VERY nice black GTR in the last photo...... Any other info and what specs?? Am also thinking that black looks great (like my RS)
LuckyP said:
Del 203 said:
..Just popped in to see what you lot are up to 
..
Just the usual rubbish... ..
& what ever you say YOU will never stop tinkering 
& Funny enough the other week this happened
Think i'm going to make a deeper one though
Anyway best i let you carry on Pete
Edited by Del 203 on Monday 25th August 16:25
very sexy Javier!
Don't doubt that workd fine. But what the wind tunnel shows and my pathetic experiments have proven (to me anyway), is that the std over cab air intake is not directly in a path +vely pressurised air, so any of our attempts to get air in using that air intake profile alone will fail. If someone designed an extention that could be added to the OE apperture (and didn't obstruct the latch) to bring it forward and up. Then we might see BHP gains with cool, pressurised air. No?
Don't doubt that workd fine. But what the wind tunnel shows and my pathetic experiments have proven (to me anyway), is that the std over cab air intake is not directly in a path +vely pressurised air, so any of our attempts to get air in using that air intake profile alone will fail. If someone designed an extention that could be added to the OE apperture (and didn't obstruct the latch) to bring it forward and up. Then we might see BHP gains with cool, pressurised air. No?
Guys Pete in particular. I think your experiment failed because you have no where but the engine for the air to go. What I would suggest is a box plumbed to the intake scoop that goes over your carb but then exhausts to the low pressure point at the tail of the car. The engine will take the air it needs from the flow going by. Just a thought, Lee
ROWDYRENAULT said:
Guys Pete in particular. I think your experiment failed because you have no where but the engine for the air to go. What I would suggest is a box plumbed to the intake scoop that goes over your carb but then exhausts to the low pressure point at the tail of the car. The engine will take the air it needs from the flow going by. Just a thought, Lee
Lee, I think that what P was trying to deduce with that little experiment ^ pictured back there was if the air intake was effective at directing air in through the scoop and to the carb and as the standard scoop is below the roof line and not even in the path of the airflow ie. negative pressure zone, it's effectiveness was neigh on to zero.Javier, nice looking C/F air box and you say that it seems to work well but I would be surprised if from what we can see in the picture there were enough inlet holes and also if they were large enough to allow adequate CFM @ high RPM for your motor. If indeed it is adequate, and I am sure that you have done the math, it must be very close.
On my canam I built vents in the rear deck, that feed a small air box. We did some testing on another builders car and found the air flow in this area to be pretty good. I wasn't looking for a ram air effect, just a place to get cold air from. Ghetto wind tunnel video http://www.markkoch.net/images/canam/windTunnel/wi...
Very interesting stuff. For me I have found slightly different results. I boxed my air filter/intake in a couple of years ago, all of the intake air comes from the top scoop and it has vastly improved things.
I only did this after a simple temperature experiment. I used an 8 channel thermocouple datalogger to probe all around the engine bay and found that cool air was making it way in through the top scoop. This could be significantly increased by removing the very restrictive grill that is factory supplied and I still run with nothing there to day.
What I now find is that the air intake temperature at speed is approx 2DegC above ambient, why? well probably because some of the air from the radiator is making its way into the intake, mixed with ambient air. Hot starting is also greatly improved, without any other exit/entry for the air the engine sees cool air even after a good heat soaking, this always used to give me starting problems in my carb days.
I only did this after a simple temperature experiment. I used an 8 channel thermocouple datalogger to probe all around the engine bay and found that cool air was making it way in through the top scoop. This could be significantly increased by removing the very restrictive grill that is factory supplied and I still run with nothing there to day.
What I now find is that the air intake temperature at speed is approx 2DegC above ambient, why? well probably because some of the air from the radiator is making its way into the intake, mixed with ambient air. Hot starting is also greatly improved, without any other exit/entry for the air the engine sees cool air even after a good heat soaking, this always used to give me starting problems in my carb days.
Even though the scoop does not ram air into it in the wind tunnel, the engine is still drawing air through it.
And this air is cooler than the air in the engine compartment.
Paul, 125f was measured at rest or at what speed?
Was this from the intake manifold sensor?
125f is not bad IAT, since the engine itself is as 200 F.
A taller scoop will give more of a ram air effect.
The real culprit is the air that has passed through the radiator.
And this air is cooler than the air in the engine compartment.
Paul, 125f was measured at rest or at what speed?
Was this from the intake manifold sensor?
125f is not bad IAT, since the engine itself is as 200 F.
A taller scoop will give more of a ram air effect.
The real culprit is the air that has passed through the radiator.
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