Tuning for Mild Cam, Headers, etc....

**Davis_1377** · 03-22-2013

Been looking everywhere to come up with a good Spark advance table or any other things to help. Running a TBI 350 with Headers, dual flowmasters with Comp Cam 12-366-4 Lift: .520"/.515" Duration: 268°/280° Lobe Separation Angle: 113° Has ecm 1227747 $42

If anyone can please help me with any of this id appreciate it. Im kinda new to this but have messed with it quite a bit so theres some smaller stuff i may not know. My map reading at idle runs about 60 kPa at about 550 RPM. Ive tried started working on its idle first to keep a good steady idle and lope but when it does start to lope right it looses its rythm.

**EagleMark** · 03-22-2013

That's not a mild cam. It's just beyond max for an EFI system. This one?
http://www.jegs.com/i/Comp-Cams/249/12-366-4/10002/-1

Operating range from 2000 PRM, not 0 RPM... hope your manual trans or have a high stall converter... then it goes to 6000 RPM so you need enough fuel there before you start tuning idle.

You'll never idle Closed Loop at 60 MAP and 550 RPM. Start at 850, may be able to get it lower later. Idle spark around 22 degrees, stock is 16.

TBI is a wet intake so the longer you idle the wetter the intake gets, worse with low vacuum/high MAP. So need to rev it up awhile after you make adjustments to dry it out, then see what data says for more adjustments.

But idle is the least of worries right now. What is estimated HP of engine? What size injectors? What fuel pressure?

This is not an easy engine to learn to tune on, here's some things we were collecting for starter tunes on built engines.
http://www.gearhead-efi.com/Fuel-Inj...odified-engine.

**Davis_1377** · 03-22-2013

Yea thats the right one. I didnt know much at the time about EFI when i started this project. I got a 700r trans right now, no stall but does good, it dont try to die in gear and it takes off easy. Im guessing the hp would be around 230-250. Fuel pressure I have not checked but my blm and int stay around 128 if its right. The injectors ive not looked at yet either i just know they are stock. Ill try what you said in the mean time.

**EagleMark** · 03-22-2013

Originally Posted by Davis_1377

Im guessing the hp would be around 230-250. Fuel pressure I have not checked but my blm and int stay around 128 if its right. The injectors ive not looked at yet either i just know they are stock.

That's a lot of cam for stock intake, TBI and heads! Let's hope it's more then 250 HP, but getting to the 6000 RPM range is going to be an issue.

Your INT and BLM of 128! Not possible at 60 MAP and 550 RPM... Must be in Open Loop! System has to go Closed Loop to see fueling changes in INT and BLM.

Don't do any WOT high RPM runs until you get some things figured out. Stock injectors and fuel pressure is no where near enough to fuel that engine, your going to be lean at WOT high RPM.

Do you have any data logs? Post them up so we can see what is actually going on.

**jim_in_dorris** · 03-22-2013

What BCC is this running?

**Davis_1377** · 03-22-2013

Here is a log file and its a ACSF bin i ran. There is a big hill at the beginning when i data logged. I also have a stage 1 and stage 2 bin that seems to do alittle better then stock. I meant my blm stays close to 128 when driving in closed loop. I dont have a heated o2 but im gonna get one later. I also have a throttle body off a 454 somewhere if it would help i could put on it, I dont know how these do on a 350.

**PJG1173** · 03-25-2013

Originally Posted by Davis_1377

Been looking everywhere to come up with a good Spark advance table or any other things to help. Running a TBI 350 with Headers, dual flowmasters with Comp Cam 12-366-4 Lift: .520"/.515" Duration: 268°/280° Lobe Separation Angle: 113° Has ecm 1227747 $42

If anyone can please help me with any of this id appreciate it. Im kinda new to this but have messed with it quite a bit so theres some smaller stuff i may not know. My map reading at idle runs about 60 kPa at about 550 RPM. Ive tried started working on its idle first to keep a good steady idle and lope but when it does start to lope right it looses its rythm.

this cam has similar characteristics to mine just less valve overlap. if your heads and intake can supply the flow this cam is going to demand at 4500 rpm and above you are going to need more fuel and a bigger TB. also 550 is too low of an idle for that cam 750+ is where mine is set to idle at with 24* timing.

**Davis_1377** · 03-31-2013

this cam has similar characteristics to mine just less valve overlap. if your heads and intake can supply the flow this cam is going to demand at 4500 rpm and above you are going to need more fuel and a bigger TB. also 550 is too low of an idle for that cam 750+ is where mine is set to idle at with 24* timing.Thats nice, That would be intersting to hear it.

That's nice, it be interesting to hear it.

**EagleMark** · 03-31-2013

You have to judge IAC counts at the end of a drive, then idle. Under 20 counts, 10 is better. But then have to look at TPS voltage, perfect is .54... .65 is OK.

Somehow your missing idle timing? It's not 22-24. Tell you what, post your bin, I'll do a couple changes for you. You have to learn how to use Compare function and Data tracing. Data tracing is already set up in the $42-1227747 files. Then when you get bin back, open it, load your stock or last bin and use compare to see what I did.

**Fast355** · 03-31-2013

Originally Posted by EagleMark

You have to judge IAC counts at the end of a drive, then idle. Under 20 counts, 10 is better. But then have to look at TPS voltage, perfect is .54... .65 is OK.

Somehow your missing idle timing? It's not 22-24. Tell you what, post your bin, I'll do a couple changes for you. You have to learn how to use Compare function and Data tracing. Data tracing is already set up in the $42-1227747 files. Then when you get bin back, open it, load your stock or last bin and use compare to see what I did.

Probably under estimating how far the idle map is pushing the idle sa area at idle would be my guess.

The TPS can be slotted and the idle voltage returned back stockish.

**Davis_1377** · 03-31-2013

Somehow I couldnt find idle timing. Compare I can use, data tracing I can figure out. The JET is the bin I was using, this is one I didnt mess up. The ACSF is the stock one, which ever one you prefer. Thanks that will help me alot.