427 big cam whipple idle timing

[69camaro5speedefi]

seems weird i have the target idle at 850 rpms and its pulling timing down to keep it at say a stock idle of 600 ,if it drops lower then 600 it adds timing if its much over 600 it takes it out
I have played with coeff. tables doesnt seem to do any thing
any big cam guys have any luck raising idle and getting timing in at idle or are we stuck raising min timing table to make it happen?
This thing will drop to -22 degs if i let it idle to long

[doc350]

Look into Idle Torque. That is what I have used before to get cammed cars to keep timing. I haven't done any really big cams though.

[69camaro5speedefi]

Look into Idle Torque. That is what I have used before to get cammed cars to keep timing. I haven't done any really big cams though.

sounds good but nothing i have found changes timing yet at idle except min timing tables

[Redline MS]

Did you fix the dyna air model? (Speed Density)? Also what is the MAF hertz when this is happening?

[69camaro5speedefi]

Did you fix the dyna air model? (Speed Density)? Also what is the MAF hertz when this is happening?

I am not sure the process to fix the dyna air model,I did a search here and did not find any thing on gen 5 stuff,maf hertz is 28xx
I have the dynamic high set to 500, have my fuel trims reading low numbers
I played with idle adapts ,Immediate and have it keeping timing in better ,sure do miss the idle timing table and idle air flow table days,
they still had a idle err tables
Idles much better with every tq pid I could log reading lower now lol
what a mess the engine ears left us lol
e92/t87 over load Back to engine dyno with simple efi on my day job

[Joshtuning]

Post the tune you have right now so we can help you more

[69camaro5speed]

Ok,let me test drive it tonight,I only drove it once while logging ,besides the install shop driving it to me witch didn't get logged, need to get my lm2 to read correct so when I get to hard loads or on my dyno it correct,so have some work to do,I just wanted it to idle at its target with put pulling timing it's close now but seems weird how I got there ,seems to be all pid base control

[Ben Charles]

Log tq management spark at idle... You have to mess with the tq coifficients to get this correct... If you want more idle tq need to increase the tq coefficients and play with the GMVE there directly related from what I can tell..

[69camaro5speedefi]

Here is a example tune and log where it was at idle pulling timing ,I later made the min. timing table a little higher at idle to crutch it for now

[409Jake]

Im dealing with similar issues on a similar combo, and found that lowering the Airmass A-D tables in the idle area is helping bring the idle up to commanded. I swagged out 80% first, then been fine tuning from there.

I dialed in the SD and Maf first and trims are in line... Still needs some work, but getting closer it seems...

[69camaro5speedefi]

ok I will try couple of these things ,has any one converted a lt1 to lt4 map,looks like lt4 has 2 maps,manifold and one for baro,
not sure if i could just add the z06 map and change setting ?

[Ben Charles]

Don't do the LT4, you will have to add a wire to the ECU bc the IAT is built in.... INstall the LS9 (direct bolt in) and change the settings in the tune.

[69camaro5speedefi]

Don't do the LT4, you will have to add a wire to the ECU bc the IAT is built in.... INstall the LS9 (direct bolt in) and change the settings in the tune.

hell yeah that's what i am talking about

[Redline MS]

If you don't solve the base air models first all the knobs your twisting will keep compounding the issues. There is no doubt a 7.0 liter engine with a big cam has completely messed up the VE of the engine. Since the dyna air model is based off pressure (P/R) vs rpm you need to populate the VE (well coefficients) with real values of air mass. Playing with torque tables or even base running airflow tables are like trying to fly a jet with the trim tabs and not the wings.

News flash...just because you lower the high speed air enable to 500 doesn't stop the SD model from still working. Unfortunately HPT does not supply all the tables needed that define the boundaries to 100% bias MAF or SD....you need to fix both...

[69camaro5speed]

Maybe I should junk the mas air lIke I do all my 3rd Gens,they get dirty or real damp and turn into a false reading paperweight anyways I seen more transmissions and motors junk from failed massair meters

[Redline MS]

Maybe I should junk the mas air lIke I do all my 3rd Gens,they get dirty or real damp and turn into a false reading paperweight anyways I seen more transmissions and motors junk from failed massair meters

There is nothing wrong with the MAF unless its maxed or in a place where it can't report credible airflow signals. I'd leave both models working if you can as that's how it is designed...

[Higgs Boson]

MAF works great w/Gen 5, IMO.

[mowton]

There is nothing wrong with the MAF unless its maxed or in a place where it can't report credible airflow signals. I'd leave both models working if you can as that's how it is designed...

^^^^^^^ I agree, not operating in Blended mode would be like turning off Torque Management in a 6L80 tune....

Ed M

[69camaro5speedefi]

There is nothing wrong with the MAF unless its maxed or in a place where it can't report credible airflow signals. I'd leave both models working if you can as that's how it is designed...

Looks like theres all kinds of problems with {I'd leave both models working if you can as that's how it is designed...}http://www.hptuners.com/forum/showth...n-Coefficients

Yes, what James is saying both SD and MAF are tuned according and operate properly independently. But when both are being utilized and its running the normal blended dynamic airflow mode, it goes stupid sometimes. The most common issues I've experienced is what James was pointing out about on boosted cars. Below the dynamic threshold before hi speed mode gets forced, the stock prediction coefficients are problematic. Most commonly I have seen it basically cut the air flow in half in boost at low rpm, which causes the car to go way lean and won't run. The quick solution is to lower the hi speed force rpm low enough to avoid the problem.

I made some posts about this stuff back in like 09-10, but no one wanted to acknowledge the problem or discuss it back then. I was doing lost of maggies in those days when the 5th gens first cam out. With boost at low rpm and trying to keep the SD functional with a high rpm disable in the 2-3k range it just wouldn't work. I tried playing with the numbers with little success. Tried numbers from a ls9 tune which obviously didn't exhibit the problem. Nothing worked for me short of setting the disable rpm to like 1K. I assumed it was a os bug or like always due to tables we couldn't see or get too. I later came up with a set a coefficients that I use, but still occasionally have issues and have to drop the disable rpm lower than I'd like.

Would love to see this cracked and us know what the real math behind it is. Many times Id like for the SD to play a heavier weighting in the blending or would like to filter the maf signal more heavily due to a dirty signal.
Last edited by Bluecat; 09-23-2015 at 10:08 AM.

[69camaro5speedefi]

So looking for ideas, set a fault on the mass air so I can tune ve.

Then set dynamic airflow rpms to like 10 to hopefully fault ve off ?

Turn mas air flow back on tune it?

Add them together, then 0 out prediction coefficients (so that problem doesn't nag me)

look for errs again and see how that does ?

While fighting with tq tables to keep transmission a live LOL

Ok left some blanks for holes a may left lol