Preparing for a Dyno run
 

I plan on getting my car dynod for the first time soon. I have some questions and requests.

First I would like to know what to do about the rev limit. I havent rev the engine past 7500rpm I would like to safely see how far it will go? The motor has 6k miles, the interals/housings are s6 the plates s5. It has a large street port. Right now the stock turbo is certainly holding the engine back.

Also can somebody give me their timing map? I just want to compare the base map that I have. Ive downloaded a few different ones and they come up wildly different. I don't know why.

Lastly, what do people do with the rev limiter? Ive heard that its better to set it high out of reach and retard the timing alot so that it limits the power. What are your recommendations?

I have a Sprint RE.

???

is your rotating assembly balanced?

set rev limit at 7500 or so to start... Depending on your streetport, you'll probably see peak hp somewhere around 7k to 8k, that is IF the turbo can keep up with whatever boost you are running. On my stock s5 turbo, I couldn't get it to hold more than 8lbs by redline. Peak HP wasn't anywhere close to 7k-8k.

After you dyno, set your rev limit just as your peak hp starts dropping, or at whatever rpm you are comfortable running, whichever is LOWER. Running 500 less RPM can mean the difference in a reliable engine or a engine that quickly wears out.

Most people run a HARD ignition cut. It usually will sound like someone is firing off a few rounds as the car backfires. This is ok for short periods. However, on my SprintRE, I couldn't get it to do this. Even a hard IGN cut sounded like a soft rev limiter. It almost sounded like FCs with a fast hunting idle but louder... hard to describe.

Good Luck, and if possible, bring someone who experienced dynoing rx7s with you.