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| Ported Head for Big Red https://www.slantsix.org/forum/viewtopic.php?t=5967 |
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| Author: | Al T [ Tue Jun 10, 2003 2:53 pm ] |
| Post subject: | Ported Head for Big Red |
I took my first shot at porting a head in early May. Here are some pics. Click on the link below each pic if you want the full size version.  http://www.projectplato.com/headportingoverall.jpg  http://www.projectplato.com/headportingpile.jpg The immediate measurable difference is that the blower builds about 1 1/2 less psi now. A 10% underdrive pulley should arrive this week. It typically makes an extra 3 to 4 psi on SuperCoupes. Should put my max boost into the 7-9 psi range. |
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| Author: | 87Slant_sickness [ Tue Jun 10, 2003 3:27 pm ] |
| Post subject: | |
looking great!!! how'd it feel performance wise after??? Justin |
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| Author: | RMDV [ Tue Jun 10, 2003 3:46 pm ] |
| Post subject: | Re-Head Work |
Hey Man, Looks good. Thanx for posting |
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| Author: | Adam [ Tue Jun 10, 2003 4:45 pm ] |
| Post subject: | |
Aaaah motivation, Just what I need. Thanks for posting that, did it increase performance a lot? |
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| Author: | Dart270 [ Wed Jun 11, 2003 7:10 am ] |
| Post subject: | |
Cool stuff, Al. Sounds like your porting increased flow quite a bit. I'm sure that more boost will = more fun! Cheers, Lou |
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| Author: | Al T [ Wed Jun 11, 2003 8:57 am ] |
| Post subject: | Porting/performance for positive discplacement blown engine |
At this point, I don't believe I've got a significant performance increase but it sets me up for the future. Here's my thinking. To some extent, I'm overcoming air flow restrictions through the head using pressure from the blower and since the blower is positive displacement, it moves the same amount of air each revolution regardless of back pressure (boost). I haven't yet increased the speed of the blower so therefore I moving the same amount of air per cycle ( and therefore the same fuel is being added & same power results) but its just taking a little less effort to do so (1 1/2 psi less back pressure). Volume of air inserted is approximately constant with rpm but pressure varies. Its a different story with a naturally asperated engines or centrifugal forced induction devices. With a naturally asperated engines, the pressure pushing air into the manifold is constant (atmospheric). Any less restriction translates almost directly into more air/oxygen in the cylinder. Pressure is constant but volume varies. With turbo's or centrigugal blowers, both build up pressure based on the rpm they're spinning at. Volume of air moved increases with less restriction. So how does less restriction set me up for the future? It allows me to decrease the amount of power consumed in order to move more air. That is, when I mount the under driven pulley, it will allow me to get more air into the cylinders more efficiently, thereby saving more power for the wheels. Trivial Note: The blowers on top fuel dragsters consume more power than a stock 426 hemi produces! |
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| Author: | Dart270 [ Wed Jun 11, 2003 10:01 am ] |
| Post subject: | |
Good points, Al. I had understood that you were moving the same air at less boost pressure (easier flow), but I had not connected that it meant you are requiring less power to drive the supercharger. Cool. Lou |
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