New build big cam tuning

[Ragin Cajun]

I've been doing all kinds of research on tuning and trying to get a basic idea of what I'm doing. I'm just starting to get deep in the tuning and have built a engine that is definitely testing my tuning abilities. So far I've put in all the correct injector data and a little adjusting on the ve tables and attempted on the maf. I'm running into a little problem with the cam though, it has a lot of overlap and is "short circuiting". I've been messing with the injection timing to try and fix this problem because my wideband readings are not trustworthy until I fix this. I have my boundary set at 7.20 and normal and makeup are set at 6.50. This should be delaying it quite a bit but its still not helping it seems. I still do not have a good understanding of how this works and what exactly is the boundary and is normal and makeup added to the boundary??? I figure I need to fix this problem before I go any further into tuning the maf and ve tables. Also, I have 60# injectors and will need to scale for this, can I do the scaling later or will I need to do this in the beginning? Correct me if I'm wrong but I will not be maxing out the injectors till higher rpms and load and I'm no where near that point yet so if I get it running and cruising alright I can do the scaling after that? Any information will help, I'm green to tuning and am trying to learn as much as I can and actually understand what I am learning and why it is doing what its doing.

[93camaro_zzz]

First off, what year/make/model is this on. Second, can you post up your tune for us to check out? From what I understand of the injector boundaries, is that you will first want your correct injector data in the car, which you have already done. And then you turn off the MAF, and dial in the VE up to a specific point like 2400rpm. Then run the car at a specific rpm in steady state, while logging afr, and do this SAME test for several different injector boundaries. Whichever setting is the richest, is the injector boundary that you will want to choose. Because that is the setting where the car is getting the most fuel into the cylinder, and the least amount of fuel that is "short circuiting", or going through your overlap period and into the exhaust.

By the way, I i just picked the 2400rpm as an arbitrary value. I would do this test at the lowest rpm that you consider stable for your car. For example, the cam lopes alot at idle, and is not really considered stable, so you might end up running this test at say 1200rpm, or 1600rpm. Hope this helps.

[Ragin Cajun]

The car is a 99 Camaro with a stock bottom end ls1. That makes sense, I did kinda what you describes but at a lower rpm and like you said, It was not stable. Now do I want to be changing the boundary or should I change the normal and makeup tables?

[Ragin Cajun]

Also the cam is custom grind 242/248 110 lsa

[Ragin Cajun]

Alright, I finally got time to tried what you said. I ran it down the road and kept it steady at 2k rpm at 60 kpa and wrote my readings down, I moved the boundaries around trying them. First I ran it at 7.20 boundary and got .96 lambda, then 6.50 and got .99, then 7.50 and got 1.01, then back to 7.20 but got 1.00 that time ??? I figured it would be see same reading with the same stuff and drove it as close as I could every time. Also, when I first start it the idle reads just a little rich but after I drive it it gets real rich at idle? I haven't looked into that to much yet.

[Ragin Cajun]

Anybody else that has some more or diff info on this would be much appreciated. I've also come up with another question as how Im I going to go abouts tuning the lower end of the ve table when Im not getting good readings with the o2s because of the overlap of the cam?

[POWERZONE]

It just depends on alot of different varibles. Sometimes I just tune in Speed Density with cams with a lot of overlap and ditch the MAF.

I have tuned some wild stuff that I had to just leave in open loop. lol

[Ragin Cajun]

Ok, ran into a little problem in the engine but dodged a bullet and got it fixed. Had a broke intake valve spring, thank god it wasn't an exhaust valve spring, that could have been bad lol. Thanks for the help, I will probably be having to keep this one in open loop but I still haven't been able to tune from 1600 rpm and below it seems. Im going off the wideband and it shows its way rich and a take fuel out and it dies or falls on its face. I have it drivable but just by feeling how it acts and adjusting. Any ideas or ways to tune down there cause with so much overlap of the cam that I cant go by the wideband??? Also, I start it up and let it warm up and drive it a little ways, come back and its ok, I drive it for a while and things seem to start changing, like it gets richer or leaner, this is in open loop??? any ideas? The tuning 1600 and above is adjusting alright it seems, trying to get good accurate data by driving on the street though.

[watman02]

I belive u have to turn off stft's Other wise it will learn the rich condition and adjust turn them off in 1600rpm and below see if that helps. I had to do that on a mustang with a big cam once even though I was comanding open loop to get it to stop adjusting and fighting me.

[Ragin Cajun]

Alright, I believe I have stft off but ill check and make sure when I can, Ill post my tune up when I can also.

[nikon1999]

Keep an eye on your IAT readings. In an SD tune they can sway your AF pretty significantly I found

[JamesLinder]

I would recommend tuning the MAF and VEs first, and make 100% certain you have the correct injector loaded in all tables.
You should be able to get the motor running really good without messing with injector timing, which is rarely necessary
anyway. If you buy a book by Don LaSota, The Ultimate GM EFI Tuning Guide for HP Tuners for $80, then you would learn how
to tune correctly much quicker. Another great book is Master EFI Tuner - GM EFI - Second Edition for $45 by Dan Maslic.

And remember, 90% of the information you get off these message boards are from people that do not know more about tuning
than a beginner, and of these about 80% will give you advice that is incorrect or is not being applied properly. Most people
modifying their injectors do not input the right data, so the remainder of their tuning is trying to get the motor to operate
smoothly on bad data. If you have good injector data, and you properly tune MAF and VE, then nearly all your problems
will be solved.

Injector tuning will only help with cold weather starting and smooth out a well running motor; it will not solve major problems
if you do not have your MAF and VE dialed in because you will not be close enough to a proper tune to evaluate the impact
you are having.

[Ragin Cajun]

Thanks for the help, I really appreciate it. My IAT readings do get a little high sometimes so I will def look at that more closely. And yes, 90% of the info you get sometimes is bs so I take everything I hear with a grain of salt, so far everyone has been a pretty straight shooter with me though. My injector data I know is 100% accurate other than the timing ive messed with, and most the time you shouldn't have to mess with the timing but most the time the cam is a little more mild also, idk, still want to sort out the timing before I go any further

[JamesLinder]

if you list your modifications and post your tune file, I will take a look at it for you. It is best if you provide your
current tune as well as GM's stock tune for your motor as it came from the factory. I've been doing this for 12
years so I might be able to help you out.

[Ragin Cajun]

if you list your modifications and post your tune file, I will take a look at it for you. It is best if you provide your
current tune as well as GM's stock tune for your motor as it came from the factory. I've been doing this for 12
years so I might be able to help you out.

Alright, Its a stock block, crank, rods, pistons (pistons are relieved) LS1, its about 11.5/1, has PRC 227 heads, custom grind comp cam (242/248 110 lsa .628/.631) is solid by the way, edelbrock super victor intake, ported low pro elbow, 102mm tb, 60# SD inj, underdrive pulley, no a/c, built 4l60e, 3200 circle d converter,... goes on and on lol. If you need to know more just ask. When I figure how to get a tune uploaded on here I will put it up and a quick drive down the road with that tune.

[Ragin Cajun]

Tune for camaro X.hptlast drive 8-28.hpl Idk if I did it right but here it is

[JamesLinder]

Did it run without any values for injector flowrate? The file you attached has no values in the injector flow rate table??????????

[Ragin Cajun]

Did it run without any values for injector flowrate? The file you attached has no values in the injector flow rate table??????????

No, I took that out when I put it on here, flow rate, offset and short pulse adder. All that info is right though

[Ragin Cajun]

I assume I posted right on here since your able to see it, I wasn't sure if I did it right or not

[02statesman]

No, I took that out when I put it on here, flow rate, offset and short pulse adder. All that info is right though

Why would you do that?

If someone is trying to help you and wants to see your tune file... they want to see the whole tune file.