1989CivicSi

Alright, so it's 35 A.M (couldn't sleep). and now that I'm positive that I fully (and man, I feel so stupid that it was so simple) understand tuning for AFR I started reading up on tuning ignition (about 3 hours ago ).

My setup will be as follows: Tune OBD0 with TurboEdit, Turbo = IHI RHB5 @ 8psi internally gated <--it's a first time setup

Well, I've got the basics down (a safe number to retard timing in a linear fashion being 0.75 or 0.8 if I'm feeling super conservative) and I was wondering if I should bother with doing a stepped ignition retard? Reason I ask is because I've read that although a linear retard won't make as much power as a stepped retard, it'll be a lot safer as ignition is tuned a lot more conservatively throughout the powerband.

However, a stepped retard allows for more adjustability and I've already written down the "safe" base values for retarding the ignition (found it while searching an hour or so ago).

With that said, from what I've heard the IHI RHb5 spools up rather quickly. So quickly that I was wondering if I should even bother with a "step"-type ignition retard? I mean, as this won't be a super high horsepower street tune anyways, would the 1k RPM range or so (until full boost) with a stepped retard make a very noticeable difference (I can see how it would make a large difference on setups with greater turbo "lag")? Or should I just stick with linear and stay on the safe side?

Final question: Would you HMT gurus recommend a .75 or .8 ignition retard for my setup (with the IHI RHB5)?

Thanks a lot for your time, and putting up with my noobness!

Chris Harris

Stepped will generally help spool...at full boost, your ignition advance should be at the same values regardless of which method you used to make your starting values.