I would like to start off by saying thank you to Rbob. He has been here since I bought his EBL P4 helping me along the way. Great guy. I am here now hoping I could get some feedback and critique from multiple people on my tune. I have made huge progress on the tune just this week. A week ago the car was barely driving and wouldn't even do a burnout. Now I can roast the tires all the way through first and it is driving great. I feel like there is still a lot more power left in it and it is not near its full potential. So let me know if you see anything I should change. I will post my bin and my most recent datalog, along with a build list.


stock block 350
tpis mini ram
195cc econo ported pro-filer aluminum heads
xr276hr cam
340 stealth fuel pump
new oem distributor
1.6 rocker arms
58 mm throttle body
shorty headers
3 inch exhaust with highflow cats and 40 series flowmaster muffler
48 lb injectors
msd 6al
stock suspension and 700r4
stock coil
stock map
If there is anything else I forgot or you need to know just let me know. All help is appreciated. I am itching to go mustang hunting and beat my buddies 77 nova and another buddies 350z. Again, thanks guys.

 

alright guys I just did a test hit and I have a better datalog. I am mainly messing with the ve tables and the sa tables and have had good results. it runs well when I am just cruising around. when I punch it I blow the tires off all the way through first and it pulls through second in to third decently. between 1800-4500 it pulls decently but after that until 6000 it really starts to PULL. I want it to PULL a lot sooner but I am not sure exactly how. I will continue my trial and error with timing and fuel but any help is appreciated. if you look at the log my hit is towards the end, my test road was oddly busy and I had to cruise for a bit to let traffic die down. thank you. ps here is the updated bin too! thanks.

 

Fuel pump can't keep up with the demand. Note how the VE% keeps rising all the way past 6K RPM. It should follow the torque curve of the engine, which peaks at about 3800 RPM:

http://www.compcams.com/v002/Pages/396/XR276HR-10.aspx

The other item which I believe we have already discussed is the spark advance. If the initial (base) needs to be at 20* BTDC, the timing mark and damper TDC mark don't line up. Which is also likely why you are commanding 38 - 39* BTDC at WOT.

Also, un-check this flag:

Option Word 7 Input Polarity - Bit 2 - 4thIn

The WUD is showing in OD when it obviously isn't.

RBob.

 

alright I am going to drop it down to 6 and see what happens. I am at tdc, the tabs line up. The reason I had it at 20 was because of the intake pop and overall bad running car. now that all the mechanical parts are performing correctly, it wouldn't hurt to try it. it was a trial and error experiment with my premature tune. I just installed an aeromotive 340 stealth fuel pump so it SHOULD be able to be strong enough. could it be ve values or the high timing that I need to change for the greater demand? thank you.

 

Doesn't matter that the (timing) tabs line up. What matters is that they line up at 0* BTDC at the same time the #1 piston is truly at TDC.

RBob.

 

they are set at 0 and the motor was set to TDC when the heads were off. I cant remember if we set it right but when I got my new distributor I am not sure if we set it the same as the computer. regardless, they are both at 6 now and its running better. i will have a datalog tomorrow.

 

OK, running better at 6* BTDC is a move in the right direction. The base setting is important as it defines the minimum and maximum at-crank spark advance. The distributor has physical limits to the range of spark timing being able to be programmed into it.

Command too much advance into the distributor and the rotor/ to cap phasing causes the previous cylinder to fire. Engine just shuts off. These two parameters define this physical limitation:

SA - Maximum SA with Positive Value
SA - Minimum SA with Negative Value

For the GM small cap distributor the max is 41.8*, the minimum is -3.8*

With the distributor base timing at 6*BTDC, the minimum at-crank SA is:

6* - 3.8* = 2.2* BTDC

With the maximum SA at:

6* + 41.8* = 47.8* BTDC

This provides a decent range of spark advance for the engine set up.

However, with the base at 20* BTDC, things get skewed. The minimum at-crank SA is:

20* - 3.8* = 16.2* BTDC

With the maximum SA at:

20* + 41.8* = 61.8* BTDC

So, with one area of the main SA table at 55.2* of timing, with the 20* base setting you will get that 55.2* BTDC at the crank.

With the base setting at 6* BTDC, that 55.2* will be clipped to 47.8* BTDC. Which is typically more then enough for light cruise.

RBob.

 

the car loves timing. cant get it to spark knock so I am continuing to add a degree or 2 here and there. it is pulling strong up until about 4600 and then it levels off until about 5400 and then it pulls even stronger. my money is on the timing but I would feel more comfortable with a second opinion. once this rain clears up ill have another datalog to post. I apologize for not posting in a few days. Thank you for the help.