Throttle bodies and barn doors!!!!
03-06-2002, 11:36 PM
#1
Three Wheelin'
Thread Starter
Throttle bodies and barn doors!!!!
Hi,
I have seen opened up throttle bodies for sale by HR, They say they are enlarged for maore air flow. Here is a hypothetical here, If one was to drill holes in the existing barn door in the throttle body, would one get the same effect??
Same thing with the AFM???
Christian
I have seen opened up throttle bodies for sale by HR, They say they are enlarged for maore air flow. Here is a hypothetical here, If one was to drill holes in the existing barn door in the throttle body, would one get the same effect??
Same thing with the AFM???
Christian
Im sure he did. 
03-09-2002, 03:02 PM
#7
Racer
Join Date: Jan 2002
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How about a free liscence plate frame and two full sheets of stickers!! <img src="graemlins/jumper.gif" border="0" alt="[jumper]" /> <img src="graemlins/jumper.gif" border="0" alt="[jumper]" /> <img src="graemlins/jumper.gif" border="0" alt="[jumper]" /> <img src="graemlins/jumper.gif" border="0" alt="[jumper]" /> <img src="graemlins/jumper.gif" border="0" alt="[jumper]" /> <img src="graemlins/jumper.gif" border="0" alt="[jumper]" /> <img src="graemlins/jumper.gif" border="0" alt="[jumper]" />
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03-09-2002, 04:49 PM
#8
Addict
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I think there's a bit of part throttle response to be gained from drilling holes in the AFM. You don't want to mess with the throttle plate though, as you would have air "leaks" at closed throttle...
I'm using a friends computer right now, when I get to something a bit more suitable, I'll post a write up on this tread about drilling the AFM door.
Ahmet
I'm using a friends computer right now, when I get to something a bit more suitable, I'll post a write up on this tread about drilling the AFM door.
Ahmet
03-09-2002, 07:40 PM
#10
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No, I'll just post it here 
.
OK, the idea is to increase throttle response (not really power), and air flow specially at part throttle-low end/midrange. Basically, drill holes in the flap (reducing the flap's mass, and restriction). But to counteract the reduced restriction, the spring tension needs to be backed off (so that the flap opens at nearly the same angle even though there's not as much air pushing on the surface of the flap), which also reduces 'lag', improving throttle response.
Basically, remove, drill, re-attach, and calibrate. For the last step, I used an exaust analyzer, and a tachometer. Ofcourse if you can tell by the sound of an engine if it's running lean/rich or near stoich, than that's a very valuable input too...
I could back off exactly 19 teeth from the spring tensioner on my car. Throttle response seems improved, but not a very significant change. I'll be honest, full throttle acceleration doesn't feel much different. It sounds a tad bit more metallic at higher revs if you're paying attention, but that's about it. However for a grand total of $0, I don't think it's a bad 'project'. Prooceed at your own risk.
Tuning the air/fuel ratio again took me about 2 hours to get just right. I did my air/fuel measurements at idle, 2k rpm, 2300rpm, 2500rpm, 2700rpm, 3krpm, and 3200rpm. After re-indexing the flap/potentiometer (the device that's affixed to the top of the flap, that generates the actual electrical input->ressistance), everything seems to work fine.
The only thing to watch for is taking the bolts off that hold the AFM against the airbox (one of them is in a tight spot, I had to 'customize' a cheap no-name bit "driver", second to last picture shows this tool), and to not get any aluminum shavings into the AFM.
PS: I did a write up of this, and the DME mod a couple of months ago for my computer app. project, more info is at my website, but be forewarned, I was literally talking out of my rear as my comp. teacher didn't know anything about cars...
And incase you're curious, my car has laid down a 7.2 to 60 with: Cam from previous owner, complete jacobs ignition system, splitfire plugs re-gapped on jacobs' recommendation, straight pipe in place of cat, borla cat-back and the mentioned AFM mod as well as a K&N drop in filter. It's also got a centerforce racing clutch, and had 255/45/17 tires. It's a no options 84 model. Since then, I've sold the borla cat back, the 17 inch wheels and the cam, the jacobs multiple spark discharge unit(still have the coil/wires/plugs), the car sits about an inch higher with factory sport pieces, instead of aftermarket. It now does consistent ~7.5 sec runs to 60 with mild abuse, on stock size 4 season tires. I'm guessing it's pushing around 167hp at the crank.
Ahmet
.OK, the idea is to increase throttle response (not really power), and air flow specially at part throttle-low end/midrange. Basically, drill holes in the flap (reducing the flap's mass, and restriction). But to counteract the reduced restriction, the spring tension needs to be backed off (so that the flap opens at nearly the same angle even though there's not as much air pushing on the surface of the flap), which also reduces 'lag', improving throttle response.
Basically, remove, drill, re-attach, and calibrate. For the last step, I used an exaust analyzer, and a tachometer. Ofcourse if you can tell by the sound of an engine if it's running lean/rich or near stoich, than that's a very valuable input too...
I could back off exactly 19 teeth from the spring tensioner on my car. Throttle response seems improved, but not a very significant change. I'll be honest, full throttle acceleration doesn't feel much different. It sounds a tad bit more metallic at higher revs if you're paying attention, but that's about it. However for a grand total of $0, I don't think it's a bad 'project'. Prooceed at your own risk.
Tuning the air/fuel ratio again took me about 2 hours to get just right. I did my air/fuel measurements at idle, 2k rpm, 2300rpm, 2500rpm, 2700rpm, 3krpm, and 3200rpm. After re-indexing the flap/potentiometer (the device that's affixed to the top of the flap, that generates the actual electrical input->ressistance), everything seems to work fine.
The only thing to watch for is taking the bolts off that hold the AFM against the airbox (one of them is in a tight spot, I had to 'customize' a cheap no-name bit "driver", second to last picture shows this tool), and to not get any aluminum shavings into the AFM.
PS: I did a write up of this, and the DME mod a couple of months ago for my computer app. project, more info is at my website, but be forewarned, I was literally talking out of my rear as my comp. teacher didn't know anything about cars...
And incase you're curious, my car has laid down a 7.2 to 60 with: Cam from previous owner, complete jacobs ignition system, splitfire plugs re-gapped on jacobs' recommendation, straight pipe in place of cat, borla cat-back and the mentioned AFM mod as well as a K&N drop in filter. It's also got a centerforce racing clutch, and had 255/45/17 tires. It's a no options 84 model. Since then, I've sold the borla cat back, the 17 inch wheels and the cam, the jacobs multiple spark discharge unit(still have the coil/wires/plugs), the car sits about an inch higher with factory sport pieces, instead of aftermarket. It now does consistent ~7.5 sec runs to 60 with mild abuse, on stock size 4 season tires. I'm guessing it's pushing around 167hp at the crank.
Ahmet