ajbutowicz

I know lots of people are doing cam swaps, myself being one of the popular LT1 cam swappers. Next step, tune the car in.

I was hoping by starting this thread we could get some of the more experienced tuners to pitch in on common changes needed to the chip when swapping in a mild cam, what they had to do, what is commonly in need of change, anything to help the people with little/no tuning knowledge (like me) *get it* a little quicker. I know reading all the posts in the DIY prom board helps, its been done, but now lets focus on just our ECM and that lethargic 305 and getting it tuned in.

Anything useful, post it here, maybe it can become a sticky.

Anyone with much more know how than me want to start it off?

Fast355

iTrader: (2)

Use WINALDL, look at the Wide Average BLM table. Then adjust your VE tables by using the BLM. Say that your BLM at 1,200 rpm and 80 MAP, is 135, divide it by 128(represents 14.7:1), then multiply the by the current VE in the VE table lets say 55%. That is 135/128x55%=58.00%. Enter that in the VE table. Do the same for the whole table. I ignore the information for any cell that has under about 10 data bits. No just the opposite, lets say your idle is rich. That would be around 114 BLM at 800 RPM and 45 MAP. For the example lets say the VE table has 28% in it. That would go as follows 114/128x28=24.93%

My timing tables start out looking like they came straight out of a 60s carbed car. I then tweak them a little from there. My formula is about 12-14* initial advance with no vacuum. I then have the timing ramp up very quickly to 30* by 2,400 rpm in the SA table. Then on top of that I add 10* of vacuum advance in by 10 in/hg. I start the vacuum advance at about 5 in/hg of vacuum. I will send you a sample .bin for a 7747 if you want. Use it at your own RISK.

MikeDirntRulez

Once you start tuning with the LT1 cam, do you have to leave it at about 8* advanced or whatever the timing needs to be at to need it to run?

Because I have emissions testing and I just want to leave it at about 4 or 6* max and have it still be able to run decent at 0* when it's time for emissions.

BMmonteSS

once your "in the chip" you can set it to whatever you want at the dissy and just add the extra timing in the chip. Thats the power of tuning your own car. So much easier to just burn another chip with more or less timing for a given situation. You'll quickly learn that there is enough adjustment in the ecm to pretty much tune for any situation. I only have two chips, an 87 octane and a 93 octane tune. The funny thing is that even with gas at 2.50 a gallon I still can't bring myself to run the 87 chip, I just have a fear that I'll need that extra 5-10 HP for somthing.

As for tuning, what fast suggested is the best place to start. Once you get your VE's in the ball park you can start playing with your timing, and then move on to AE (better known as pump shot).

a mack6

iTrader: (1)

What does MAP, BLM, and VE stand for????

BMmonteSS

I could just tell ya to do a search, but here's a quicky definition for each.

VE - Volumetric efficency, what you modify to change fueling

MAP - Manifold Air Pressure, measured in KPA (metric) 100 kpa is full throttle, and 20 and lower is really high vacume. Most cars idle between 30 and 50.

BLM - Block Learn Multiplyer, this is the correction term your ecm uses to correct fueling. 128 is perfect above this and your lean, below and your rich. You aim to get your BLM's +- 10 for a ruff tune and +-5 for a decent tune and +-2 for a spot on tune. Those are ruff guidlines.

BMmonteSS

Here's some more info to help you along.

Your ecm calculates how much fuel to inject based on a VE table that is listed by MAP and RPM on two axis. So say you have a reading of 50 map @ 2000 rpm, your ecm goes to this table and looks to see what VE is in this cell. Say it's 30% it then calculates how much fuel to inject. Now say your datalogging and you see on your winaldl screen that your 50 map and 2000 rpm cell has a BLM of 138. So your new calculated VE entry is 32.3% based on the above listed formula. Next time you log, your BLM value should be 128 in this cell. This is how you correct VE table for different modifications such as cams and exhaust.

This process is broken down into one small baby step, there are many factors to take into acount while doing this.

ThraxXx

I just want to pipe in and say that i Have been reading the DIY prom tuning boards and have been super lost and after reading this post I now see the light. This post is damn good for beginners. Now I have the confidence (and urge) to burn my own chips. Thanks guys...awesome thread

91RockS

Good info here. I am also getting ready to do the LT1 cam swap. I have a good understanding of what the tuning process will require, but posts like these really help to explain in more detail. I've been trying to find a post that puts everything together, meaning what order to tune the various tables and the best method to tune them.

BMmonteSS

Just gotta ask, your probably more likely to get better answers to beginner questions here. So post them up.

ThraxXx

so to make changes to the VE table you use Win ALDL? At any point in time will you need to user Tunercat?

Ronny

iTrader: (1)

Thrax: winALDL makes no changes. it is a datalogging program. gives you a host of data such as BLM's, OL or CL, IAC counts, RPM, coolant temp, error codes, etc. i recently opted for Tuner Pro RT4.0 that gives me a few extra advantages datalogging. check their website.

I use TunerCat (aka TC) to change my parameters in my .bin. i can adjust my VE tables, idle speed, AE(pumpshot) PE, etc.etc.etc
Check their website.

Then i burn a new chip with my programmer(PP2).

and then repeat process a multitude of times.

Ronny

iTrader: (1)

PS the above is old school. i am resistant to change. A-B-C.

BMmonteSS

Some of this info is TBI specific, keep in mind that tunerpro can datalog and edit your bin

Quick Guide:

Scanners: Winaldl Most Popular
Tunerpro 4.0 Nice, but no neat charts

Bin Editors: Tuner Cat Most user friendly
Tunerpro 4.0 Most comprehensive, and free

Burners: Pocket Programer Old school baby
Moate's Flash and Burn CHEAP....does not do 2732's

You need to do these things in this order, datalog, edit bin, then burn new chip. You can do it all real time no stoping with one of the nifty emulators out there now and tunerpro 4.0 realtime.

sscamaro327

Not New, Just A Noob. But Once We Get All The Logging, Burning ,Bins And Def Files .
Where Is The (Real) Correct Place To Start ?
Id Like To Get My Engine To Crank Like It Used To. (1 Rotation) Instead Of 5.
I Also Think She Wants To Be More Efficient (ve) tables.
Runs Fine On A Somewhat Fudged Stock Program , But Tends To Like The 110-150mph Ranges (yes,i said 150), Better Than Bottom End.
Please Suggest Something. Poor Girl Just Sits Outside. Wanting To Purr.
ALSO IM TOLD FUEL INJECTION AND LOPE ARE BAD COMBINATION ?
IS THIS TRUE ? http://www.youtube.com/watch?v=nNLtVDuNWTU <---
sure sounds good to me. Lope And Fuel Injection. Any Help I'd Appreciate.

Brandon2350

Its not impossible and it can be tuned. but my experience is the bigger the change (weather its a cam, heads, whatever, the more time consuming it is...from a beginners standpoint anyways. My cam idles at 60 map with a ton of overlap and I've tuned it using stock TBI induction. it just takes time and commitment thats all.

sscamaro327

I Have Tried Several "Tunes" I Do Have The Car Where It Will Run, And It Runs Okay Around Town , I Can Tell The Volume Efficiency Needs Help, Possibly The SA And A Few Other Things. I Have Plenty Of Time And I Am Definately Commited To Getting It Tuned. I Have Spent Months Reading Thru The Posts /Stickies Etc. But Being New At Editing Program , And Doing It Correctly Is My Problem. I Read About The VE Tables , And They Say To Change Values And Retune , I Use The Data Logger And You Cannot Change The Tables In The Datalogger (Where Are The Changes Being Applied) ???Prior To Burning To A New Chip.
We Took A 305 Engine , Bored It 30 Over, Bigger Valves Ported And Polished Intake /Exhaust We Added A Big Cam (Forget The Specs) Used Stock Intake
I Bought 350 Truck Injectors, Has 3" Exhaust Fron To Rear, Stock Manifolds
Cold Air /Ram Intake Not "Big" Mods , But Sure As Heck Hits 150Mph Easy.
Probably Been Over That , A Few Times , But I Tend To Pay More Attention To The Road At Those Speeds.
I Have Logged Data , Read , Edited ,Burned Chips Logged Data Edited. Etc.
But I Feel Like Im Going In Circles Without Knowing The Correct Place To Start.
you could say start with the ve tables, but every engine is different, along with the mods, but if were taught that every engine wants something different, then there are bound to be correct parameters to start with.
Thanks Brandon For The Reply.
Lol I Feel Like A Reject Here, But THe Only Dumb Questions..................

BMmonteSS

Have you read through the "free tune" sticky at the top of the forum? I go over how to begin your tune step by step with lots of pictures. If you still have questions try asking something a bit more specific. It's kinda hard to go over all that needs changed and how without knowing exactly what you are having a hard time understanding.

I believe the key item that you are missing is how the BLM routine works and how to take that data to how much and where to change your VE tables. The "free tune" thread goes over that.

Ronny

iTrader: (1)

I think we all started with setting the BPC accurrately in our .bin. From there get some CL correction data with a datalog. Start logging in neutral with car up to temps. Then consider a ride with no abrupt changes in throttle. Just a leasurely cruise. You will see a trend on resulting BLM's. I found that if the trend was high BLM's (lean) I overcompensated to rich in VE tables and worked the tune back to enlean. Getting the VE table reasonably close is step one. Then work on AE second. I was fortunate to discover that PE fell into line as commanded if VE was close. Above was before I owned a WB.

Brandon2350

The datalogger is just that. All that its doing is giving you information of what your current setup is doing. Indicators. For example: if your datalogger is showing a map value of 50 at idle, that indication alone tells you that your VE is probably off where as a typical map value for stock programming is around 30 Map...Meaning that in this situation your setup would most likely be really rich and the VE at that map value and that RPM range would have to be lowered to give it less fuel. You would open up your editor, open up your Main Fuel Tables, and lower that value where your vehicle idles. I hope this helps a little. It know it can be frustrating at first trying to figure it out all. My advice is take your time, read the stickies and go about it slowly. Dont try and make the perfect chip immediately. theres no such thing. My suggestion is to start playing around with fuel at idle. Change values one at a time. Keep a written log and evaluate your change by datalogging. I hope this Helps.

sscamaro327

Thanks Ronnie, Hey Heres A Dumb Question I DOont Remember Seeing An Answer To ......
To Really Know My Engine, I Need To Know The Cubic Inches, And Volume Of The Cylinders
Lets Say We Take A Stock 305 Engine Bore It 30 Over , How Would You Find The Correct (New Engine ) Size , And Volume. For Guestimating The VE.

And, Do You Need To Know Your Valve Sizes And Flow Rates On The Heads , To Calculate The Efficiency. Somewhere Along The Programming Trip?

BMmonteSS

I don't have the formula handy, but there are plenty of displacement calculators on the net to help you. It really doesn't matter because boring the engine really doesn't change the displacement enough to really matter. A .030 over 305 is like a 310.

There is no quick way to calculate what your VE is going to be. Most people are led to believe that with a list of parts there is some magic formula that will give you a new VE curve when in reality there are so many factors that come into play it's best to just monitor whats coming out the tail pipe and adjust whats going in to reach a desired result. This is taken care of by the BLM routine in your ECM. It's basically how the ECM looks at the O2 sensor and comes up with a factor to adjust the fueling. We look at the BLM's to see where the VE table no longer matches up with what the engine really needs and tune for 128's or no correction. Once we know the VE table is tuned for 14.7 (what the stock O2 see's) then we can accurately adjust the WOT paramters to reach AFR's other than 14.7. Thats the theory anyway.

Ronny

iTrader: (1)

Hi Monte... When I added EBL I found I could not get a VE under 100 where my VE was i will assume most efficient. that was I think 2800-3200 50-70 MAP. I ended up having to deviate(fudge) greatly with my BPC to pull the tables under 100. That worked for me. Is the code that we work with designed(GM) for typical production cars that are, how do i say it, compromised as far as efficiency?

IOW my car has little restriction intake.exhaust so as to be very efficient?

I ruled out all vac/ext leaks affecting VELearn. This spring I verified header collector/ext pipe a good connect as that is where the 02 sensors sit. My WB checks with NB reasonably close so BLMs are real. Only discrepancy is idle A/F on WB shows 15.5/16.0 steady and that may be cam. Ext smell none and is clean. No surge either at 850 rpms.

BMmonteSS

Grumpy would kick my ****, but I start my tuning by having no more than 85% in my VE tables and then adjusting my BPC untill my BLM's are in the ball park. Then I know when I start tuning the VE tables that I'll have enough room to tune. Of course by fudging the BPC the pump shot and AE settings will also be equally skewed so they'll need tuned. 9 times out of 10 they need tuned anyway so there really isn't any time lost. With a wideband it really doesn't matter what numbers you have plugged in as long as the engine is getting what it wants.

ownor

iTrader: (5)

hey guys, great thread here. sorry for disturbing the peace of a dead thread, but i just can't figure out what the last two posts from ronny and monte are all about
what has the VE/BLM got to do with BPC? afaik, BPC being a constant should be calculated and set, and then be forgot about, no? i'd be grateful if someone could clarify this scenario and involved changes. tia

Ronny

iTrader: (1)

Quote: I ruled out all vac/ext leaks affecting VELearn. This spring I verified header collector/ext pipe a good connect as that is where the 02 sensors sit. My WB checks with NB reasonably close so BLMs are real. Only discrepancy is idle A/F on WB shows 15.5/16.0 steady and that may be cam. Ext smell none and is clean. No surge either at 850 rpms.

you are correc!. It is set in and forget it. When you have a VAFPR you set the WOT 100 MAP to the base pulse constant then the MAP 90-80-70 also has to set to an increased amount. That is a calculation.

So if the VE tables are in excess of 100 you need to determine why. In my case I ran the EBL day one and I saw those VE tables increase over 99 on first datalogs(VELearn). I will suggest that was due to a header flange leak that I since addresssed. With my BPC set accurately I see VE maximums now around 91-92 and I suspect that may be on high side.

I will suggest if BPC is accurrate and VE is over 99 there is a error or problem somewhere

ownor

iTrader: (5)

okay, thanks for your reply. also, i found the following post to be helpful in clarifying what you were saying: https://www.thirdgen.org/forums/post...14-post22.html