I have been reading the posts in here with a lot of interest. I cut and paste what I think is important into a Word Doc for reference, but I am totally lost. I am getting LS1 edit next week and don't have a clue where to begin. Looking for some pointers. Here are mods and I will be starting with a stock program >>>

352cid
10:1 CR (estimated)
42lb SVO injectors (FP set at 43psi)
SLP 85mm MAF
Stock Valve size, heads P&P
LS6 intake
Stock TB
Cam is 114lsa 221/227 .561/.570

What are some good basic things to tackle first?

And then what do I need to fine tune?

Any head start will be greatly appreciated! From what I have read, there are many knowledgable people out there! <img src="gr_grin.gif" border="0">

Thanks!

 

Man! Not all at once! I can't take it all in! <img src="gr_tounge.gif" border="0">

 

[quote]Originally posted by Reckless:
<strong>Man! Not all at once! I can't take it all in! <img src="gr_tounge.gif" border="0"> </strong><hr></blockquote>

You've got to understand, it's just not that cut-and-dry. You can't just expect everyone to say "just do this and this and you're set."

Every car will be different. Before you start any editing, I'd make sure you're starting from scratch. If you've got Hypertech (or anyone else's programming), take it out. Remember, you can always save it and reload it if you need to.

In your case, you'll want to start with the injectors. The factory injectors (in pounds per hour) are 28.6 for 98s, 26.4 for 99-00 and 28.8 for 2001 and up and, like yours, they're also rated at 43.5 I believe (someone correct me if I'm wrong please). You'll need to adjust for the larger injector, but you'll also need to account for the lower fuel pressure. If you have a 98, divide 42 (your new injector size) by 28.6 and you get 1.47. In your "Injector Flow Rate" table, simply multiply the numbers there by 1.47 and that should get you pretty close for stock fuel pressure. It's just a guess, but I'd assume you can use the formula sqrt((new PSI/oldPSI)) * old flow rate = new flow rate. I guess this would work the same for grams/second or lb/hr. this gives you .866 (sqrt(43.5/58)). Multiply the values in your table by this number and now you should be pretty close to where you need to be. (Again, feel free to correct me!)

There's also a place where you can account for you're extra cubes but I doubt the change is significant enough to matter. I guess it wouldn't hurt to change it though. Just remember, it's per cylider so you'll need to divide your 352 by 8.

Now that your injectors are taken care of, the car should at least be driveable. Next, I'd do things like fan settings, disabling DTC checks and set the speedometer.

I'm still learing about adjusting idle (as far as fuel and spark). The idle speed is straight forward.

That leaves performance tuning. There's not going to be a magic set of numbers to put in there. It's going to be trial and error. Start with getting the correct mixture first because that can affect spark (knock). If you don't have access to a wide band O2 sensor, you'll have to rely on your stock ones. They can be fairly accurate thought. Once you feel comfortable with your fuel, (most people shoot for .890s with the stock sensors at WOT), you can adjust your spark. Without a chassis dyno, it'll just be hit and miss. There's no guarantee that more advance will yeild more power but that's typical. Just watch out for pinging. Again, most people end up with right around 30 degrees advance with a combo like yours.

Okay, that's enough typing for now...

[ March 10, 2002: Message edited by: sross ]</p>

 

May I make a suggestion to anyone changing the parameters to their PCM?
What you are doing is essentially a research and development project. Knowing what your have changed and the results it has produced is important to achieving what you want.

Keep a logbook.
Enter date and time. Make note of the parameters of what the before settings and conditions are. Also this is a good time to make AutoTap files of what you want to change.

After you have made changes and road tested you car write down the above things plus your impressions of what happened in enough detail that if you go back in 6 month to try to figure out what you did it will be clear what happened.

Taking the AutoTap files and making graphs of the before and after can be a big help.

For variables that can interact with each other change only one thing at a time.
Try not to over adjust something, sneak up on the desired setting.

 

BluVette....that is one of the best suggestions I have ever had. I'm glad you chimed in. So simple, but so important in the long run. Nothing is worse than trying to remember what you did and what the effect was.

Thanks! <img src="graemlins/gr_cheers.gif" border="0" alt="[cheers]" />
Todd

 

[quote]Originally posted by sross:
<strong>

In your case, you'll want to start with the injectors. The factory injectors (in pounds per hour) are 28.6 for 98s, 26.4 for 99-00 and 28.8 for 2001 and up and, like yours, they're also rated at 43.5 I believe (someone correct me if I'm wrong please).
[ March 10, 2002: Message edited by: sross ]</strong><hr></blockquote>

I think they're rated @58PSI anyone have a definitive answer or a tech data sheet?

 

Stefan,

That's exactly the kind of info I was looking for. Just wanted to know what to address first to get the car running good, then I can tweak from there. I appreciate it.

Ed Wright tells me he will simply unlock my program, so I won't have to do quite as much as I thought originally. Should be able to tweak Ed's work for optimal performance.

Todd

 

[quote]I think they're rated @58PSI anyone have a definitive answer or a tech data sheet? <hr></blockquote>

I have flowed stock injectors and the flow rates quoted above are correct. These rates are at the LS1 4 bar fuel pressure (58psi.)

-Jeremy

 

So stock injectors are rated at 58psi? And SVO injectors are rated at 43psi?

That's what I always thought.
Todd

 

Thanks for the info guys...that is much more meaningful than...Hey, I changed these #s and man is it sweet. You are very helpful.