Hey guys ive been trying to tune my new 350 with zz4 cam and Holley TBI. When I load my modified bin to Tunerpro using the 8063.ecu file my VE table looks messed up. Ive been running extremely rich blms around 105. Ive been trying to edit the table to get my blms around 128 using the 105/128(table value) formula and ive done this maybe 5 tuning sessions so far and it really isn't helping infact the blms seem to drop further down?? When I loaded my stock bin into tunerpro the main ve table looks fine but when I loaded my modified bin in its all messed up. Do you think I should just use my stock ve table then edit it from there??

Main VE table
rpm map (kPa)
20 30 40 50 60 70 80 90
3200 53.91 49.22 84.38 92.19 97.66 99.61 99.61 99.61
2800 96.88 51.95 48.05 81.25 91.80 97.66 98.44 99.61
2400 94.14 70.70 50.00 46.88 77.34 86.72 92.97 96.09
2000 92.19 78.52 94.14 48.83 44.92 73.05 82.81 91.02
1600 84.38 72.66 90.23 91.41 45.31 39.06 71.09 80.08
1200 69.92 79.30 67.19 70.70 87.11 42.19 36.33 65.23
800 52.34 60.94 42.97 55.86 82.03 84.38 39.06 33.20
400 15.23 36.33 44.92 60.94 67.97 71.09 78.13 32.03

Stock Motor was 88 LO3

 

I always like to start with stock bins. As for the calculation of BLM / 128 * VE = newVE, that is correct. Have you changed the Base Pulse Constant to match the new TBI and engine displacement? That may be part of the reason the BLMs are so low.

One thing I don't like about the table shown (above) is that some values are already close to 100%. The Main VE table has an Adder table that goes with it. The two table values are added together for the final VE% value. Any final value greater then 100% is truncated to 100%.

This may be part of the reason you aren't seeing any changes in the BLM.

RBob.

 

How would I figure out what my Base Pulse Width should be. I did some searching but couldn't find anything. Right now I have it set at 135.

 

The BPC is typically calculated with the engine displacement and injector flow rate. Here is the equation:

BPC = 1461.5 * (VOL/RATE)

VOL = Vol of 1 Cylinder in liters
RATE = Injector flow in gms/sec

As an example:

For a 350 & 61.2 #/hr injectors (basically a stock L05)

VOL = 0.7125 l/cyl = 5.7 / 8
RATE = 7.71 gms/sec = (61.2 / 3600) * 453.6

BPC = 135 = 1461.5 * (0.7125 / 7.71)

However, depending upon how high the engine rev's and how much HP is is really going to make, the injectors may need to flow more fuel. In this case the BPC will be lower.

RBob.

 

Thanks RBob! The formula works great!

 

Cool thanks, so using the formula with the Holley Tbi injectors rated at 65pph I get a value of 127. I'll try that to see what happens. Anyways I changed my Main Ve Table around to the values that were in a L05 bin. I did a run around the block staying under mostly 2500. At idle my BlMs still averaged in the 105 area. During cruising and light throttle my blms stayed around the same 105, but I even saw it dip to as low as 96. I also had code 43 pop on and stay on till I shut the car down. I just changed my esc to a 350 model so Im not sure what might be happening there. Also do you think maybe the Holley injectors maybe to much for my motor??? Or maybe my 02 might have gone bad?? Also in my modified bin from tbichips.com(just using this to get started) he set it so my Ve adder tables were at 0 from 800-2800rpm.

 

what the fuel pressure? i recall holley runs a higher FP than GM. 65 lb'ers certainly are not too large.

 

I backed it all the way down. I believe its at 11 or so.

 

Alright I changed my BPW to 125 but it is still very rich at idle blms around 108 on stock L05 Ve Table. Do you think maybe I should advance my base timing some more? Right now its set at 8 with about 25 degrees total advance. Also I still get code 43 and it stays on till I shut the car off.

edit:I just found this post when doing some searching that figures in the fuel pressure into the BPW. He has the same specs as me and his BPW is 83. Maybe I need to drop mine way down.

 

JP is running 28 psi where you are running 11 psi, big difference. At idle with the ZZ4 cam you are in a different area of the VE table then a stock L05 would be. You need to tune the VE tables, simple as that. The stock tables will not work.

As for the code 43 my bet is that the engine can't force knock. Which in turn is a failure. There are patches for the '8746 & '7747 to eliminate the forced knock test. None that I know of for the '8063.

Your timing should be OK, concentrate first on getting the VE tables squared away.

RBob.

 

what are the specs on the ZZ4 cam. is it that large to force BLMs to bottom out? are you certain they are 65 lb injectors?

look at the 800 rpms 20-30-40 map VE table. seems those values are quite large. i assume you are datalogging tunerpro RT? or same with winALDL?

 

I think Holley rates them as 85pph injectors but thats flowed at like 20 psi or so. I read somewhere on the tbi board that at like 10 psi there rated at 65pph. Im gonna go work on my VE Tables and see where that gets me.

Heres the zz4 cam specs.
0.474" Intake/ 0.510"Exhuast hydraulic roller
208 / 221 degrees @ 0.050 lift 112LSA

Im datalogging with Winaldl and editing with TurnerPro 4.0.

 

when i contacted Holley they stated their 670 cfm had 65 lbs rated at 20(?). i asked if they will sell me unit with substitute 80lb'ers and they said not. i would have needed to buy the 670 unit with 65 lb and swap at added cost. maybe now they have a diff program or prior owner had swapped in larger inj's. i would check part # to be certain what you have.