mig1980

Good day everyone. I had an A&A Vortech V2 supercharger and supporting mods installed about a year and half ago and the tune is just not right. I am looking at taking it in to Synergy Motorsports in Livermore, CA to retune it.

My vette is a 98 and given the limitation with the MAF, I was thinking of going Speed Density. Any thoughts on this?

Also, what parts would I need to purchase (would like to purchase everything ahead of time) to make the change?


Thank you

jmxp69

When I convert, I'm doing a MAF delete, so I'm getting a standalone IAT, Casper Breakout Harness, and an A&A MAF delete pipe. You'll also need a 2bar MAP sensor (or 3bar depending on your boost level).

tblu92

You can run the STOCK MAF based tune---It all depends on how much HP you are making
A MAF tune is more street friendly and always better to use it you can. A MAF tune makes continuous adjustments to P/T AFR so no matter the weather-altitude or air density it will always be correct --If the P/T fuel is correct and you should never have any extra enrichment of fuel during WOT---A SD tune is a set tune for both P/T and WOT therefore as conditions change the tune does NOT change-- On a dedicated race car you would have to make AFR changes at every track or every day to get the most HP the car can make----On a DD not worth the trouble
The way to know if you need a SD tune is by logging your MAF HZ table---The stock HZ table ends like at 12500 HZ --So if at WOT you log something close to or Higher than 12500 you have gone beyond the usable MAF table--When going above the table the MAF locks on the last entry at 12500 and no more fuel is being added to compensate for more air and the car can go lean
There are other options instead of SD---An OLSD tune is a popular choice for a street application---The MAF is still used but not for P/T applications and fuel corrections

mig1980

That's interesting stuff tblu92. I have never heard of OLSD. My issue currently is that I was told the 97-98 computers as well as MAFs are very limiting. I have had a couple times where I had codes thrown for being too rich on both banks. I have also had issues with pinging. I am not heavy on the foot 98% of the time on my vette and it is mostly a garage queen. The funny thing is when I had the codes thrown I wasn't even getting on the car. I was driving normal.

I know a lot of people swear by an SD tune and I am just trying to figure out the most stable long-term solution for me.

tblu92

You have a set of whole other issues not related to your MAF---
Yes the early MAF's were limited as they topped out at like 11000 HZ and the newer ones at 12500--However RICH codes are always P/T related !!!!!
Typically rich codes are caused by LT headers---It is an inherent nature of the beast -The 02 bungs on LT's are like 3' further aft and that causes erroneous 02 sensor voltages---A rich or lean code is triggered when your P/T fuel is about 20% off----
You have to remember that any POSITIVE fuel trim will be added to your WOT fuel as well as a safety -not a big deal at PT but at WOT if your fuel is20% lean the ECM will add 20% to your WOT fuel as well
As an example if you engine is tuned for a safe 12.4 WOT fuel if you add the 20% now you have a pig rich 9.92 WOT AFR !!!
A negative fuel trim however always locks on a "0" fuel trim at WOT so the ECM will never subtract fuel at WOT as a safety
Your pinging issue is a completely different problem not related to the rich codes---Early C5's had many knock sensor failures which will cause pinging---
The only way to see if you knock sensors are bad is to have a tuner data log your timing ---It could be your last tuner simply added way to much timing----
It gets rather complicated but to diagnose the pinging you have to compare your "Commanded timing" or asked for timing VS your "Actual timing " what the data logger shows you are ending up with---Most early C5's only need about 20-24* ACTUAL timing \\
As far as te RICH codes are concerned--All that is needed is to log your LTFT fuel trims and make an adjustment in your MAF table to get your trims in line--Best is slightly negative or "0" during ALL P/T operation
You need to sort out the stock Ol/CL MAF tune 1st before ever considering a SD tune--- which in my opinion is NOT required for your application

mig1980

Good points. Before I go down the route of SD, I will be taking it to a reputable tuner in my area with hopes to correct some of these issues. BTW, my car does not have headers. All stock from manifolds back with exception of Z06 exhaust (all because of SMOG issues in CA).

All of these issues started occurring after the tune was done. Didn't have any issues prior to that. While tuning, the tuner did mention to me a few things and one was that I was running 12* of timing. Not sure if that is too little or too much. Tuning is not my forte.

AFR was right around 11.4 across the line.

jmxp69

How much boost are you seeing?

tblu92: This question sort of piggy backs on the issue I asked in my own thread. Aside from the HZ limits on the stock MAFs, there's also an airflow max the ECM can register. In my case: 512g/s. A one bar MAP also pegs at--well--one bar. I see 104kPa max in my log. With 10psi on my setup, I peg both metering devices. Since I'm ECM limited, options are a scaled tune or 2bar SD.

If the OP is exceeding the capabilities of his ECM/MAF/MAP Sensor (which is why I'm curious about his boost level) wouldn't an SD tune provide more accurate air flow metering capabilities unless he got into a scaled config?

mig1980

I was told max boost of 10 lbs. Have seen that much on the spirited drives I have done but haven't pushed it that hard.

tblu92

Yes I have tuned boosted Corvettes with a stock MAF setup but they had about 8-9 lbs of boost Typically when you hit 10 on a 97-00 you run out of MAF table and require another type tune--I've always opted for an OLSD tune---for a DD--
10* of timing seems a little lowbut if your tuner logged KR then he has more info than I do--Also if you increased the compression ratio with LS6 heads or smaller comdstion chambers the timing would again have to be lower-Typically a boosted LS1 with stock heads you should be able to run 12-12* timing at WOT with an AFR in he low 11's

directnosfogger

this is interesting to me tblu. I did some thinking about your recommendation to OLSD. What are your considerations or pro/cons to when you would leverage an open loop tune with VE only vs closed loop with 02's? Would you consider it just as safe to run open loop as closed loop?

FRiCK916

Since bill is no longer tuning for force fed, ide recommend you go to synergy. Purchase the A&A MAF delete pipe, IAT sensor and bung with the right harness... solder the harness into the maf harness I think it's the purple and brown wire.. SD tune away.

And I think I suggested bill to you the first go around, not mark