diypnp tune help
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Junior Member
Joined: Apr 2010
Posts: 35
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From: Rexburg ID
Car: 1988 iroc z
Engine: 350 TPI
Transmission: 700r4
diypnp tune help
hey i just installed the diypnp from diyautotune on my car. i got it to idle. starts up great and revs good but with my limited tunning experience i was just wondering if someone on here with a little more experience could give me a crash course on how to tune the car. any help would be apreciated. definetly already starts easier and revs much better than the stock computer though. plus help with boost tuning would be a great help too as i am going to throw a turbo on it soon too.
Junior Member
Joined: Aug 2010
Posts: 12
Likes: 0
Re: diypnp tune help
Well, the good news is that getting the engine up and running is often the hardest part. Once you're past that stage, the main things to focus on are the VE table (main fuel table), acceleration enrichment, and spark timing. In that order.
The VE table is pretty straightforward - you set a number as a function of MAP sensor reading and RPM. Bigger numbers are more fuel. You'll want to set the VE table at idle to whatever pulls the most vacuum (lowest MAP sensor reading). Tune it for 14.7:1 or a little leaner when cruising (generally, under 50 kPa, and RPM above idle). At full throttle and naturally aspirated (100 kPa), you'll probably want around 12.5:1 to 13:1. Once you add boost, aim for around 11.5:1 to 12:1. A wideband will help you nail down the boost and full throttle numbers.
Acceleration enrichment is something you'll want to add just enough fuel that it doesn't bog when you floor it. This page explains how this setup works.
http://www.msextra.com/doc/ms2extra/...ual.html#accel
Spark timing is the hardest - it's tough to get this nailed down without a dyno. Our Nova timing table might be a good starting point. As a general rule, the "advance until it pings and then back off" approach tends to give too much timing on a small block Chevy and may hurt power. Although you will want to back off if it pings, what you want to do is advance the timing until it stops making power, which is often a bit before it starts pinging.
There's more articles on tuning for the DIYPNP here:
http://www.diyautotune.com/tech_arti...yno_tuning.htm
http://www.diyautotune.com/tech_arti...squirt_ems.htm
The VE table is pretty straightforward - you set a number as a function of MAP sensor reading and RPM. Bigger numbers are more fuel. You'll want to set the VE table at idle to whatever pulls the most vacuum (lowest MAP sensor reading). Tune it for 14.7:1 or a little leaner when cruising (generally, under 50 kPa, and RPM above idle). At full throttle and naturally aspirated (100 kPa), you'll probably want around 12.5:1 to 13:1. Once you add boost, aim for around 11.5:1 to 12:1. A wideband will help you nail down the boost and full throttle numbers.
Acceleration enrichment is something you'll want to add just enough fuel that it doesn't bog when you floor it. This page explains how this setup works.
http://www.msextra.com/doc/ms2extra/...ual.html#accel
Spark timing is the hardest - it's tough to get this nailed down without a dyno. Our Nova timing table might be a good starting point. As a general rule, the "advance until it pings and then back off" approach tends to give too much timing on a small block Chevy and may hurt power. Although you will want to back off if it pings, what you want to do is advance the timing until it stops making power, which is often a bit before it starts pinging.
There's more articles on tuning for the DIYPNP here:
http://www.diyautotune.com/tech_arti...yno_tuning.htm
http://www.diyautotune.com/tech_arti...squirt_ems.htm
