New Heads and CAM--Retarding at WOT??

[rcwilbur]

I have a 99 C5 corvette with manual transmission. I installed a black wing and headers and re-tuned the car. This past week I then installed heads and a cam (224R). I have not run the car for more than 75 miles or so, and ran it with the same tune. The A/F ratios look pretty good. They are maybe a little rich at WOT and in power enrichment mode (above 4000 RPM) 12.4 or so. These are about the same numbers I saw without the heads and cam.

Question is: I am seeing some retard at wide open throttle. On the attached log it appears at Fram 4213, again at 5479, 6122 and 6285. Just wondering if this is normal or there is something I should do in the tuning to correct.

Attached is the log file and the configuration file.

Thanks very much.

[mecanicman]

Take ftc out of your chart and put knock retard in. You will see whats pulling your timing. To much timing from the looks of it, pretty much whenever you see 28 plus degrees at wot. Pull your timing back.

[rcwilbur]

Take ftc out of your chart and put knock retard in. You will see whats pulling your timing. To much timing from the looks of it, pretty much whenever you see 28 plus degrees at wot. Pull your timing back.

Thanks very much for your help. I think I do have knock reard in the chart--second section labelled "retard (deg)." I have never messed with timing at all on the prior tune--it is just the stock timing. Is it normal to have to decrease the timing from stock with these types of mods?

[mecanicman]

the config you posted it didnt show up, so removed ftc and put it in. Becomes very obvious. Alot of these vehicles come with knock in the stock tune. A tune always involves setting the timing. Better heads will promote a faster burn, a faster burn requires less timing.

[rcwilbur]

Take ftc out of your chart and put knock retard in. You will see whats pulling your timing. To much timing from the looks of it, pretty much whenever you see 28 plus degrees at wot. Pull your timing back.

Here is the Standard Tune that came on the car when I bought it. Pretty sure this is what came from GM--the guy I bought it from had not done anything to the car.

I looked at the timing table (same one as is on the car) and it shows timing dropping to 25 at 4800 RPM and .72 g/cyl and higher Air Mass. Then for 5200 RPM and above it goes up to 28. There is also kind of a weird timing drop in the timing at 2400 RPM and .12 g/cyl. I wonder why there would be that kind of drop?

[witchertorque]

when you put bigger heads and cam you increase your airflow so the ecm sees the increase in airflow as an increase in load thats why it pulls timing so you have to tune it

[rcwilbur]

Take ftc out of your chart and put knock retard in. You will see whats pulling your timing. To much timing from the looks of it, pretty much whenever you see 28 plus degrees at wot. Pull your timing back.

Here is the Standard Tune that came on the car when I bought it. Pretty sure this is what came from GM--the guy I bought it from had not done anything to the car.

I looked at the timing table (same one as is on the car) and it shows timing dropping to 25 at 4800 RPM and .72 g/cyl and higher Air Mass. Then for 5200 RPM and above it goes up to 28. There is also kind of a weird timing drop in the timing at 2400 RPM and .12 g/cyl. I wonder why there would be that kind of drop?

[rcwilbur]

the config you posted it didnt show up, so removed ftc and put it in. Becomes very obvious. Alot of these vehicles come with knock in the stock tune. A tune always involves setting the timing. Better heads will promote a faster burn, a faster burn requires less timing.

Thanks very much for your help. Makes sense. Everything I've read suggests more timing--I just assumed that the stock tune would be way conservative in terms of staying away from knock and if I didn't try to advance the timing, I would be okay.

I will go in and pull timing and see if that gets rid of the knock retard.

[ingsteve]

you also have positive +LTFT at wot (incorrect fueling). Please check your maf tuning middle to high Hz and retune

[Somer1]

Same boat but to the EXTREME can somebody look at this and tell me whats wrong. PLEASE!!!

[edcmat-l1]

Same boat but to the EXTREME can somebody look at this and tell me whats wrong. PLEASE!!!

Looks like timing is jumping around. The big dip looks like torgue management. Hard to know exactly what the roughness is caused from without seeing the tune, or logging different PIDs. Could be in an area of the table where the timing is uneven.

[Somer1]

The motor is in front of a TH400 with no VSS, I sent the ECM out for tuning for the Heads and cam but it has less power now then stock. I'm new to HP tuners and am not savy with it at all. I'm just looking for a reason that might cause the timing to go crazy. The MAP, MAF, O2 sensors are all new. also this is a drive by wire engine. I also sprade around the intake to check for leaks, didn't find any.

[edcmat-l1]

I don't doubt it. That tune needs some help.

What's the combo?

Whoever tuned it for you dropped all the timing out of it over 6 grand. PE settings all need changed. VE looks bone stock.

Not sure exactly why the timing is that jumpy, but the big dip corresponds with the shift. I'd zero out the TM timing tables, and the burst knock. Then make sure the primary timing tables are setup where you would normally travel horizontally, that the timing is the same. Hope that makes sense.

[Somer1]

it's an 04 Escalade LQ9 with Texas Speed 2.5 LS6 Cylinders heads and a 224/228R 112
lsa 585/588 cam. They wrote the tune. Ok bare with me I'm pretty savy with motors and such and actually did a lot of dyno tuning with motorcycles but DynoJet software for motorcycles is way easy to grasp then this. So I'm gonna need some help with the jargen. PE,VE,ect. Thank you for your help this has been 3 weeks in the trouble shooting department and I have missed a few events and the major one being this weekend I'm running tight on time. (Off-road races).

[rcwilbur]

Sommer--I am new to HPTuners too. It takes some time to be able to navigate all of the different screens and settings in the software and to understand what you are doing and why. I spent a lot of time reading background material, which will give you answers to questions like what is VE and PE. There is a lot of material here under the help tab and in the two Stickys posted on this forum page that will help.

Not trying to avoid your question, its just that there is a learning curve to begin to use this product and all of the above information will help. It did for me.