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Registered
Join Date: May 2008
Location: Austin, TX
Posts: 201
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Injection Timing Question and Ignition timing too
I'm getting pretty deeply into tuning my newly rebuilt engine.
First what is it: 1982 SC block with 100mm Nickies, JE Pistons (10.05:1 compression ratio as cc'd) Heads: '82 SC heads twin plugged Supertec valve springs, Ti retainers, 36 mm ventiport inserts, new valves and guides. Stock rods with ARP rod bolts Hargett ITBs with 46mm butterflies, Ford Motorsport 39lb/hr injectors, Toyota Tundra COPs, SSIs and a Monty 2 in 1 out muffler. Cams- DC 60 with 106 lobe centers. EFI- MoTeC M800 Now my 2 questions: 1. The MoTeC allows me to specify either the time fuel injection begins or ends in degrees BTDC. I bought the MoTeC used and the program that was in it had injection ending 320 degrees BTDC. That seems awfully early to me. I moved to 270 degrees at idle to 200 at 7500 rpm redline. I think I could keep going closer to TDC: maybe 250 at idle to 160 at redline. What do you think? 2. I had used Jamie Novak and brads911sc timing comments on their build threads, but both of them are using distributors. I have more flexibility with electronic ignition. I found these graphs on Steve Wong's website.   My engine feels like it wants a lot more advance than I am currently running. I am running something that looked like the WOT curve from Steve, but with Jamie and Brad where they are I hesitate to go 40 degrees of advance. I'm using MAP as load I don't know what load is on the graphs on Steve's website. Is the only thing to do spend time on the dyno? I tried going to use much as 30 degrees on the road the other day, it is more powerful, but the lambda went from 0.90 to 1.08; so I added fuel, but I worry how much timing is safe with twin plugs and 93 octane fuel and 10.05:1 compression and my DC 60-106 cam? Thanks in advance for any help, Richard
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Original owner 1986 944 1987 951 968 wing from CPR, Deutsche Nine headlights, KW Variant 3s, Lindsey Stage 2 intercooler, Big Reds 2003 Ruf 3600S S-Car-Go equal length headers, otherwise almost stock 72 911T w/ SC 3.3SS engine MoTeC Hargett ITBs |
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07-17-2010, 01:04 PM
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Registered
Join Date: Mar 2006
Posts: 820
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PM me your email address and I will get you some info.
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07-17-2010, 04:26 PM
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Navin Johnson
Join Date: Mar 2002
Location: Wantagh, NY
Posts: 8,787
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How is the ignition and injection configured?
Batch fire/waste spark? Sequential/sequential? It makes a difference.. If batch fired injection end angle doesn't really matter.. Need to know more about fuel and ignition set up. Being able to sit and drive against a dyno for few hours is time well spent
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Don't feed the trolls. Don't quote the trolls  http://www.southshoreperformanceny.com '69 911 GT-5 '75 914 GT-3 and others |
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07-17-2010, 06:02 PM
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Registered
Join Date: May 2008
Location: Austin, TX
Posts: 201
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Injection and Ignition are both fully sequential.
Adjustable FPR from Marren set to 3 bar. Toyota Tundra (denso) COPs two per cylinder What else do you want to know?
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Original owner 1986 944 1987 951 968 wing from CPR, Deutsche Nine headlights, KW Variant 3s, Lindsey Stage 2 intercooler, Big Reds 2003 Ruf 3600S S-Car-Go equal length headers, otherwise almost stock 72 911T w/ SC 3.3SS engine MoTeC Hargett ITBs |
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07-17-2010, 06:16 PM
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