engine specs!, big four!!!!!! |
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engine specs!, big four!!!!!! |
kid914 |
Oct 20 2011, 02:56 PM
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#1
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ALWAYS lead...NEVER follow!!!! Group: Members Posts: 2,534 Joined: 9-March 11 From: Canada Member No.: 12,811 Region Association: Canada |
I hope someone can help me.
I would like to rubuild my type IV INTO A BIG FOUR. I am wondering if anyone who's done it has ...or know;s someone who has a complete engine specs sheet to share.. (IMG:style_emoticons/default/drunk.gif) Any help is greatly appreciated. kid914 |
TheCabinetmaker |
Oct 28 2011, 06:20 AM
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#2
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I drive my car everyday Group: Members Posts: 8,304 Joined: 8-May 03 From: Tulsa, Ok. Member No.: 666 |
Quote Valy "But I'm happy to see that he likes my grind. It took me a lot of R&D to figure what I should use".
I'm confused. Are you saying you developed the web cam #73 amd Jake got it from you? |
Valy |
Oct 28 2011, 01:09 PM
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#3
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Senior Member Group: Members Posts: 1,677 Joined: 6-April 10 From: Sunnyvale, CA Member No.: 11,573 Region Association: Northern California |
Quote Valy "But I'm happy to see that he likes my grind. It took me a lot of R&D to figure what I should use". I'm confused. Are you saying you developed the web cam #73 amd Jake got it from you? No, I'm saying that it took me a lot of R&D, including static and dynamic analysis to figure out the correct cam that I need. It so happened that webcam #73 was almost what I wanted but my math showed that 3% more duration on the exhaust will be very slightly better. That 3% is about 6deg but since webcam grinds the camshafts with 5deg granularity, this is what I ordered. By the way, I had to model the L-Jet flexible rubber boot between the AFM and throttle to accurately get those results. I also said that I'm happy to see that Jake reached the same conclusion with his cam, as this only confirms my calculations. |
r_towle |
Oct 28 2011, 01:15 PM
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#4
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Custom Member Group: Members Posts: 24,591 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
Quote Valy "But I'm happy to see that he likes my grind. It took me a lot of R&D to figure what I should use". I'm confused. Are you saying you developed the web cam #73 amd Jake got it from you? No, I'm saying that it took me a lot of R&D, including static and dynamic analysis to figure out the correct cam that I need. It so happened that webcam #73 was almost what I wanted but my math showed that 3% more duration on the exhaust will be very slightly better. That 3% is about 6deg but since webcam grinds the camshafts with 5deg granularity, this is what I ordered. By the way, I had to model the L-Jet flexible rubber boot between the AFM and throttle to accurately get those results. I also said that I'm happy to see that Jake reached the same conclusion with his cam, as this only confirms my calculations. Interesting. Did you have your heads flowed? Are you making certain assumptions as the baseline for the camshaft choice? Rich |
Valy |
Oct 28 2011, 01:58 PM
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#5
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Senior Member Group: Members Posts: 1,677 Joined: 6-April 10 From: Sunnyvale, CA Member No.: 11,573 Region Association: Northern California |
Quote Valy "But I'm happy to see that he likes my grind. It took me a lot of R&D to figure what I should use". I'm confused. Are you saying you developed the web cam #73 amd Jake got it from you? No, I'm saying that it took me a lot of R&D, including static and dynamic analysis to figure out the correct cam that I need. It so happened that webcam #73 was almost what I wanted but my math showed that 3% more duration on the exhaust will be very slightly better. That 3% is about 6deg but since webcam grinds the camshafts with 5deg granularity, this is what I ordered. By the way, I had to model the L-Jet flexible rubber boot between the AFM and throttle to accurately get those results. I also said that I'm happy to see that Jake reached the same conclusion with his cam, as this only confirms my calculations. Interesting. Did you have your heads flowed? Are you making certain assumptions as the baseline for the camshaft choice? Rich I modeled the ports. Turns out that in the fine tuning, the flow itself is not sufficient as it doesn't correctly account for the back-pressure. The 90deg immediately after the valve creates turbulence. I considered bigger valves, higher lift and longer duration. The lift may cause piston clearance issue. Bigger valves contains a $$$ factor (unless you're there anyway), weakens the head and doesn't scale well as the gases from one side of the valve travel even more than the ones on the other side. Longer duration was cheap for me as I needed a cam anyway and the longer time the gases exit help to average the head temperature over time but it increases the overlap and you get crappy idle since the FI is fulled into thinking there is no airflow (but I know how to handle that (IMG:style_emoticons/default/smile.gif) ). Too much overlap and the low RPM band will be hurt from the same reason + the AFM dumper jitters (also solvable but more work for me). For reference only, with the D-Jet you can fix the idle but the low-mid RPM range will not be nice and don't know how to solve. |
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