LT1 intake manifold / injectors misting
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From: Austin Texas
LT1 intake manifold / injectors misting
I looked at a spare manifold I have, from the underside, and judged that the fuel entry holes were quite a bit shrouded inside the runner. Given the manifold was designed for multec technology and given I'm running bosch III which John at FIC has shown "mist" much better, I thought I should at least unshroud the inside of the runner where the fuel enters, with the thought being it might allow more fuel dispersal by preventing coalescence of the droplets by having that aluminum shrouding gone. So I spent some time with the grinder and there's quite a noticeable difference between an unworked runner and those I worked. It looks better, but, any thoughts on whether that unshrouding work will have any effect on supporting increased fuel atomization ?
Melting Slicks
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From: Olive Branch (Memphis suburb) MS
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From: Austin Texas
Too bad, I didn't snap a photo of the "before" scenario, but trust me, it was like the injectors were the eggs in a birdies nest, buried waaayyyy down in there. Now at least, I'm friggin convinced a substantial amount of the spray from the bosch's won't be hitting a sidewall. Seemingly there ought be an effect but who knows. Here's a shot below. Anyone with an unmolested manifold need only pop an injector in there and make a comparative view and ask the same question I did.
Gasket matching is mostly worthless except to those not in the know of where most of the air flows into the port, so I didn't do any "gasket matching"
http://www.patentsearcher.com/manif.jpg
Racer
Joined: Jul 2005
Posts: 387
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From: Indian Trail, NC
Thanks. That color don't get seen much it seems. Rare stuff.
Too bad, I didn't snap a photo of the "before" scenario, but trust me, it was like the injectors were the eggs in a birdies nest, buried waaayyyy down in there. Now at least, I'm friggin convinced a substantial amount of the spray from the bosch's won't be hitting a sidewall. Seemingly there ought be an effect but who knows. Here's a shot below. Anyone with an unmolested manifold need only pop an injector in there and make a comparative view and ask the same question I did.
Gasket matching is mostly worthless except to those not in the know of where most of the air flows into the port, so I didn't do any "gasket matching"
http://www.patentsearcher.com/manif.jpg
Too bad, I didn't snap a photo of the "before" scenario, but trust me, it was like the injectors were the eggs in a birdies nest, buried waaayyyy down in there. Now at least, I'm friggin convinced a substantial amount of the spray from the bosch's won't be hitting a sidewall. Seemingly there ought be an effect but who knows. Here's a shot below. Anyone with an unmolested manifold need only pop an injector in there and make a comparative view and ask the same question I did.
Gasket matching is mostly worthless except to those not in the know of where most of the air flows into the port, so I didn't do any "gasket matching"
http://www.patentsearcher.com/manif.jpg
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Joined: Jan 2009
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From: Austin Texas
Thanks. I'm going to have my machinist mill the region where the injector interfaces the manifold to be flat at that point. Not much difference, maybe 0.200 from what I've done.
Look at the port velocity map section of the link below and understand where most of the area of the port through which most of the air is flowing. I made my unshrouding in view of this - most of the air flows through those ports in the fast zones, and airspeed is critical to power and torque. When I did my heads, I kept that in mind and from it realized why chevy engineered the port the way they did, and didn't go ape on the grinder like lots of folks might be inclined to do, lke "port matching", which basically f*cks it up. Less shrouding at the manifold where the injector pisses undoubtedly leads to better misting, but I'm not a guru and I hope someone will tell me there's no value in this so I don't waste time swapping out the manifold.......... before I swap the heads that is.....
http://www.gofastnews.com/board/tech...ort-areas.html
In any event, the shrouding around where the injector met the runner was un-necessary. If it were necessary, it would have been cast more carefully so as to be uniform, which it wasn't by any means. Another manufacturing variance, which should be read as an "opportunity".
Look at the port velocity map section of the link below and understand where most of the area of the port through which most of the air is flowing. I made my unshrouding in view of this - most of the air flows through those ports in the fast zones, and airspeed is critical to power and torque. When I did my heads, I kept that in mind and from it realized why chevy engineered the port the way they did, and didn't go ape on the grinder like lots of folks might be inclined to do, lke "port matching", which basically f*cks it up. Less shrouding at the manifold where the injector pisses undoubtedly leads to better misting, but I'm not a guru and I hope someone will tell me there's no value in this so I don't waste time swapping out the manifold.......... before I swap the heads that is.....
http://www.gofastnews.com/board/tech...ort-areas.html
In any event, the shrouding around where the injector met the runner was un-necessary. If it were necessary, it would have been cast more carefully so as to be uniform, which it wasn't by any means. Another manufacturing variance, which should be read as an "opportunity".
Last edited by ChrisWhewell; May 17, 2009 at 09:35 PM.
