rob20rx7

Just dropped off the car at Lashway Motorsports to get the car tuned for the new supercharger. Tuner asked me what I'd rather go with SD tune or MAF? We ended up going with an SD tune but are there any disadvantages?

schpenxel

Why not use both the MAP and MAF, like the factory?

Bottom line it's just two different ways of calculating airflow. One actually measures it, one estimates it from manifold pressure & RPM.

GeneSch

Post up mods and numbers please.

rob20rx7

LS7 with stock internals, LSX CNC ported heads done by WCCH. Crower solid shaft rockers with Manley double springs. Eps cam 228 / 244. 639/639 115 LSA +4 advance. T1 supercharger with 4" blower pulley 8.5 inch ATI damper. Kenny Bell BAP, Alky control meth. Car was making 568 RWHP with 516 torque while NA

0Shane@CountyCorvette

Looks like a nice setup, but no need to delete the MAF. It would be best to tune for both the MAF and VVE (SD).

-Shane

0ProChargerTech

Doing both is always a good idea.

There are a LOT of discussions, about this via the net. A little searching brings up lot of info.

Unreal

Swap a carb on it. So much better than either of those.

Whatever your tuner is good with. Both are good, both have advantages. At your power level no reason to mess with SD though.

red9r

At what power level should you start looking at SD?

0ProChargerTech

When you have large injectors and or can't properly scale the MAF signal.
Or you have a large cam, and want to clean up throttle transitions.

Not really a "HP" thing, more of an application thing.


However, that being said personally I have tuned over 1,300HP on a MAF.
I know other guys have gone as high as 1,800+HP. Just depends on whos doing the tuning.
Pretty rare to see that high of HP on MAF tunes these days.
Since most people want the advantages and options stand alones bring. (and advanced traction control)

Unreal

More than that blower can ever support.

Like PCT said, people have done maf tunes upwards of 1300+rwhp. My car is ~1200rwhp and runs maf tune.

rob20rx7

I'm looking to be around 700 rwhp, I want to run a BOV on the charge pipe about 12 inches before the TB, tuner stated with a maf tune that would affect the tune installing a BOV there. So he decided that SD tune would be the way to go.

Unreal

Yep, if you are going to do silly things like that, then SD is the way to go. BOVs should be before the FMIC.

rob20rx7

Im keeping the A&A BOV in its location (pre Intercooler) but want to add the Tial 50mm bov for looks on the charge pipe

SteveDoten@ARH

You are in good hands with the crew at Lashway.

Interesting topic you have brought up, look forward to seeing the responses from the Veteran tuners here.

0ProChargerTech

The problem is most "Veteran" tuners, are not going to spend the time to argue on the internet about the right/wrong ways of doing things.

It reminds me of the video going around Facebook called "The tuning triangle"

https://www.facebook.com/video.php?v=379707192214593

I can remember a time that "tuners" thought you had to turn off fuel trims on cars with long tube headers, or cams. Then came the Speed Density only or it will never run right, then was the MAF only for proper load. Literally pages and pages and pagessssssssss of worthless reading. It seems to come in waves.

Still to this day, I come across LS cars with the following
- No Fuel Trims (not even short term)
- Totally hacked PE tables
- Timing table skewed due to incorrect MAF changes
- KNOCK SENSORS TURNED OFF!
- And the very best one, drilling a hole in the TB to raise idle

I know I said my .02 on the matter.

0ProChargerTech

And with this as well.

schpenxel

HAHA, that video was great

I heard that once upon a time it was common to only change injector flow rates and then rape the PE table until you got whatever you wanted out of the tailpipe.

I'll also don't understand people who post tunes and say it's only x amount of timing.. then there's not a cell in the whole timing table that matches that number, lol

0ProChargerTech

I know I got a kick out of it.

Still common practice by many even these days sadly.

Well, take an example I saw recently and it really did match. Because they are removed every modifier the car had to adjust timing, from the base map. (Cliff notes below)

Guy had a tuner "tune" his LS swapped hot rod. Guy spend good money on the ECU, and custom harness to make it perfect, all new sensors (including o2) only to have the "tuner"....

Turn off all spark adders (modifiers)
Turn off all trim functions (short and long term)
Turn off the MAF (SD only)
Turn off the knock sensors (completely off)
Didn't even use the set screw to raise the idle. (Drilled a hole in the blade)

So there you have it. A guy paid really good money to have a nice OEM ecu, and harness installed. After the "tuner" removed all those functions, he has basically turned it all into an over priced Carburetor. (except now the owner could fix it with a jet change) Oh and ruined a nice new aftermarket throttle body.

After turning everything back online and setting everything up proper, all issues were fixed. Car no longer smells at idle, stopped hunting, stopped pinging under low speed high load, etc. And drives as it should, and hauls the mail.

Finding tuners that will take the time to do it "right" are what make cars run good, and last a long long time. The Ford boys have it easy with these new Coyote cars, they are soooooo easy to tune, hence why there are so many mail order companies. The ECU's are just wicked. (and having onboard widebands, and active knock sensors is icing on the cake)

schpenxel

Wow, that is crazy. Although some of the "tunes" I've seen on the HPT forum make me really scratch my head. I've been doing this less than a year and still, it's like some people have NO desire to learn how to do it correctly, no matter how long they've been doing it or will be doing it.

I saw one the other day where the guy had the PE table maxed out up top.. injector duty cycle up around 120%, and he couldn't figure out why it was going lean.

I've wondered for quite some time why OEM's haven't already switched to widebands. Is it cost, longevity, reaction time...? All of the above perhaps? I had a 2004 BMW once that did have widebands, so it was obviously possible even 10 years ago.

Unreal

I've seen a vendor (and site sponser) charger a guy $500 for a custom tune, and all that was changed was skip shift off, speed limiters off, and high octane map +2 on every cell. Just highlighted the whole map and added 2 degrees. Nothing else changed.