rjkZ28

hey everyone i just installed an ms4 cam and getting the car tuned on april 7th, and im still not sure what tune to do exactly. the place im getting it tuned at does both. im just trying to figure out if i get a speed density tune when its like 50 degrees out will i have to get it tuned again when its hotter out? also what are the disadvantages are to the speed density tune over maf? ( i have searched alreadY)

rjkZ28

also too its an extra $150 more to get it speed density tune, is that really worth it?

cast iron

MAF cars generally react well to changes, like I/E/H/C since the increase in air flow is being picked up and fuel adjusted accordingly.

SD cars tend to have crisper throttle response, but will need to be retuned with changes in exhaust, intake, heads, etc...

For a daily driver, Go MAF; weekend warrior, SD.

Frost

iTrader: (45)

That cam will likely drive a little better in SD

transAm-98

iTrader: (1)

Leave it up to the tuner. When I had my cam only setup it was initially a Maff tune, but we kept having problems with the o2's so we converted to SD and and haven't had any problems since. However some cars tune perfectly well with the MAff. Just see what your tuner is more comfortable with.

rjkZ28

the tuner told me they do both, and they can tune to whichever way i like. im just more concerned that if i get a sd tune when its cool outside im gonna have to get it re tuned again when its warm out. im willing to pay more money for the sd tune if it means its gonna run better.

chrisok1

I actually had this conversation with my tuner today. MAF tune all the way unless it is a pure race car. Your drivability will be much better with a standard tune because the car adjusts to changing weather much better. A speed density tune is fine in a race car because all you need is idle, burnout, and WFO.

Frost

iTrader: (45)

That's not true, maybe for open loop speed density, but that's for race cars or hobby-tuners (guys that ride around with their laptops like always) or people who don't mind taking the car back by the tuner her and there to check on or touch up things. Closed loop speed density allows for trimming which keeps things inline, though if the tune is thorough, it won't really be an issue [climate changes]. On large cams, SD just drives a little better, maybe it's the absence of reversion through the MAF, but it's not imaginary.

chrisok1

Good to know, I was just going off what my tuner said. He actually had one come in today that he had to correct-whoever did the SD tune did not have a clue what they were doing. He changed it to a MAF tune. Seems like SD tunes are a lot more work and take more expertise to get right? Are they really only better for huge cams or forced induction?

rjkZ28

i would like to hear what other people with ms4 cams did?

transAm-98

iTrader: (1)

Some cars just respond better to one tune vs the other. I had a cam in my 346 that my tuner had tunned with a maf in a handfull of other cars but my car just kept having issues. It's been in a SD open loop tune for the last 2 years with no issues all year long in all types of weather with no adjustments, this was also while it was still my daily driver. We actually just changed it to a closed loop SD tune today to try something else out.

1999 SS

iTrader: (3)

how large of a swing in weather conditions would affect the drivability in SD cars? if the tune is set when the weather is 85 and dry how much differently will it run when its 96 and humid or driving on warm summer nights when its 60 or 70 degrees out?

im considering going SD in the future, ive hada lot of mods done to my car and redone over the years and ive never been totally happy with the tuning even after having the tuner go over it again and again.

Tuner@Straightline

I just tuned a MS4 Z06 last week. I tuned the VE table up to 4400rpm, then re enabled the MAF and calibrated that from idle to 6700rpm at WOT. If you were to look at the scans, the dynamic air flow calculation, and the MAF air calculation only vary +-2% through out the whole range. This gives you the best of both worlds. This is done with a loaded dyno in order to get high loads at low rpms.

I've found that doing a tune this way allows for you to keep the MAF, and still retain great drivability. Now there are instances in which SD tuning is going to be better, such as any boosted application, or if you get turbulant airflow across the MAF giving you a speratic MAF signal. As long as you don't have those two things, you can stay with the MAF.

Frost

iTrader: (45)

That's how I roll too

1320 killer

iTrader: (6)

If you go SD it will make the car more streetable but unless your making 700 rwhp I would just go with a maf tune. my car made 613 rwhp on a maf tune.

GuitsBoy

iTrader: (4)

If the tuner is charging more money for an SD tune, In my opinion, it means that his MAF tune is incomplete. An extensive tune requires running in speed density to proplerly tune the VE table. This is very important for proper fueling during transients and unsteady throttle before the MAF has a change to level out.

Personally Id get the SD tune, but tell him to enable the MAF after the VE table is tuned. I always felt that MAF gave me far more accurate fueling than SD. I can put my A/F right on the money wherever I want it.

JoeyGC5

iTrader: (24)

You can tne it either way. I ran my MS4 Stage 2.5 LS6 headed motor in SDOL and SDCL without any issues either way. Running in Closed Loop with MAF was a ain in the *** though. My 416 runs like a champ in SDOL as well

7420NW7TH

iTrader: (8)

I've got a pretty big cam and gave up on getting the MAF tune right. I made my own SD tune (its really not that hard) and I'll NEVER go back to a MAF. Street manners are 50x better. Although I will say that I also run a permanently installed LC-1 so I can see whats going on with the AFR at all times. Without a wideband, I probably wouldn't run an SD tune.