<div dir="ltr"><div>Hi Mark,</div><div> For a racing setup, you spend most of your time in the upper RPM range that would be "all in" advance on a mechanical distributor. I'd recommend starting with an advance curve that mimics that, then fine tuning for small gains on the dyno if you have the chance. </div><div><br></div><div>My typical starting point for a curve is a very simple line that starts advancing at 2000 rpm, then maxes out advancing around 4000 rpm. </div><div><br></div><div>No added advance below 2000 rpm makes it easier to verify your idle advance with a timing light accurately.</div><div><br></div><div>I prefer to install the programmable distributors at 16 or so degrees static, NOT at TDC. This helps with starting, and also improves rotor phasing at max advance.</div><div><br></div><div>On the 123's, the rev limiter setting isn't always 100% accurate, sometimes you need to program the rev limit a few hundred RPM higher than intended. </div><div><br></div><div>I've attached a picture showing an example of a basic starting point for the advance curve.</div><div><br></div><div><br></div><div><br></div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><div>Jason Sukey</div><div><span></span><span></span>JS Performance Motoring, LLC<br></div><div>440.984.7720</div><div><a href="mailto:jason@jsperformancemotoring.com" target="_blank">jason@jsperformancemotoring.com</a><br></div><div><a href="http://www.jspmparts.com" target="_blank">www.jspmparts.com</a></div><div><a href="https://www.facebook.com/JSPerformanceMotoring/" target="_blank">https://www.facebook.com/JSPerformanceMotoring/</a><br></div></div></div></div></div></div></div></div></div></div><br></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Thu, Oct 23, 2025 at 3:18 PM Mark Cook via Fot <<a href="mailto:fot@autox.team.net">fot@autox.team.net</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div style="color:rgb(0,0,0);font-family:arial,sans-serif;font-size:12pt"><p style="margin:0.1rem 0px;line-height:1">All,</p>
<p style="margin:0.1rem 0px;line-height:1"> </p>
<p style="margin:0.1rem 0px;line-height:1">I am installing a 123ignition distributor (laptop programmable) into my "project" TR6 race car. Wondering if anyone has this installed on their TR6 (or 250) race car with triple weber 45 DCOEs. I thought about downloading the tuning curves from the 123 disti in my running #95 TR6 race car as a starting point:.</p>
<p style="margin:0.1rem 0px;line-height:1">I realize the camshaft would make a difference in the settings, so my specs below. Both have 1.55 roller rockers. Thoughts?</p>
<p style="margin:0.1rem 0px;line-height:1"> </p>
<p style="margin:0.1rem 0px;line-height:1">The "project" car engine has a Racetorations race camshaft, triple Weber 45 DCOE and a CR of about 12.5:1. The camshaft specs are:</p>
<p style="margin:0.1rem 0px;line-height:1"> </p>
<p style="margin:0.1rem 0px;line-height:1;padding-left:40px">Peak Diff: Exh / Intake / LCA - 108.0 / 107.0 / 106.0</p>
<p style="margin:0.1rem 0px;line-height:1;padding-left:40px">Duration: Intake / Exhaust - 336</p>
<p style="margin:0.1rem 0px;line-height:1;padding-left:40px">Cam Lift: Intake / Exhaust - 370</p>
<p style="margin:0.1rem 0px;line-height:1;padding-left:40px">Checking Clearance: Intake / Exhaust - 0.010"</p>
<p style="margin:0.1rem 0px;line-height:1;padding-left:40px">Valve timing (at checking clearance) - Exhaust: Opens 96 BBDC / Closes 60 ATDC, Intake: Opens 62 BTDC / Closes 94 ABDC</p>
<p style="margin:0.1rem 0px;line-height:1;padding-left:40px"> </p>
<p style="margin:0.1rem 0px;line-height:1">The camshaft specs in my running TR6 are:</p>
<p style="margin:0.1rem 0px;line-height:1"> </p>
<p style="margin:0.1rem 0px;line-height:1;padding-left:40px">Peak Diff: Exh / Intake / LCA - 105.0 /103.0 / NA</p>
<p style="margin:0.1rem 0px;line-height:1;padding-left:40px">Duration: Intake / Exhaust - 320</p>
<p style="margin:0.1rem 0px;line-height:1;padding-left:40px">Cam Lift: Intake / Exhaust - 340</p>
<p style="margin:0.1rem 0px;line-height:1;padding-left:40px">Checking Clearance: Intake / Exhaust - 0.010" (I think, but not certain)</p>
<p style="margin:0.1rem 0px;line-height:1;padding-left:40px">Valve timing (at checking clearance) - Exhaust: Opens 87 BBDC / Closes 53 ATDC, Intake: Opens 57 BTDC / Closes 83 ABDC</p>
<p style="margin:0.1rem 0px;line-height:1;padding-left:40px"> </p>
<p style="margin:0.1rem 0px;line-height:1"> </p>
<p style="margin:0.1rem 0px;line-height:1">Thanks,</p>
<p style="margin:0.1rem 0px;line-height:1"> </p>
<p style="margin:0.1rem 0px;line-height:1">Mark Cook</p>
<p style="margin:0.1rem 0px;line-height:1;padding-left:80px"> </p>
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