legacycentral bbs

If you have any interest at all in tuning, or just have a curiosity about how the how the stock computer works, I'd highly recommend picking this book up. It's a pretty easy read. I picked it up Friday evening, and finished it on Saturday. It gave some of the theory behind tuning and why things are done/configured the way they are.

I had a couple AHA moments while reading it. For example, injector timing. I didn't alter this from the base map on the Link. The ECU was configured to finish the fuel injection at 360 BTDC. The intake valve timing is set at 6 degrees BTDC on the turbos. The book indicates that you want to finish the fuel injection before the intake valve opens to help it atomize. Plus if you inject directly into the cylinder you can wash the oil film off the cylinder bore.

Since the ECU was still injecting a little bit when the intake valve was opening, I had a little bit of fuel being injected directly into the cylinder. The AHA moment was when I read that this causes a pretty big loss in torque. This explains why my torque curve dropped off relatively quick compared to some of the other curves I've seen from turbo legacies.

Anyway, here's a link to Amazon. I highly recommend the book.

Engine Management: Advanced Tuning

Ok im buying it this week.

How does spraying fuel onto a closed intake valve help it atomize? Is it the pressure difference when the valve opens or something?
Would it spray directly onto the cylinder wall if the valve was open? Wouldn't the fuel spray at least bounce off the intake port wall and valve a little bit before entering the cylinder? I just don't understand how that can be. It seems like a direct path would be better but fuel takes a mysterious path.

The other side of the valve is in the combustion chamber, and therefore going to be hot. When the fuel is sprayed onto the hot valve it helps cool the valve and evaporate the fuel.

Plus if it gets injected directly into the cylinder it may not have as much time to mix with the air and provide as homogenous of a mix.

Thanks for that review! That's another book on my "to buy and read" list.

Please let us know what improvements are made to your car when you implement the things you've learned from the book!