SPANKY LS1

iTrader: (24)

What are the advantages in tuning via speed density? Is it easier or harder to tune without a MAF?

Mainly just curious, I keep seeing people going to SD tunes, and was curious why they were doing so, what the advantages are? Is it simply because HP Tuners has made it possible, and people are just experimenting or are there performance/tuning advantages to it?

Thanks, Shawn

Black02SS

iTrader: (36)

SD tuning was around before HP Tuners. The reason most chose SD is because the MAF is out of calibration once you start modifying the car. You tune the car in SD, re-calibrate the MAF, and then re-enable it.

NoGo

iTrader: (2)

It's great.

Talk to someone who's car is SD from the factory and they are looking for an MAF kit.
Talk to someone who's car is MAF from the factory and they are looking for a SD tune.

You can make slightly more power with an SD tune if you change the induction system (ie get rid of the MAF). Additionally, with larger cams SD tuning will give better driveability. Aside from that though, it is just gives tuners something to 'tune'. Kinda like Lterms......

HumpinSS

iTrader: (1)

Better control over fueling. One less sensor mucking around with stuff and if the maf is outtta wack and you scale the maf you are hiding any problems that may exist in the ve table namely transient fueling. So you unplug it dial the ve table in the re-cal the maf and go about your business

HumpinSS

iTrader: (1)

Wow havent seen you around in a while. Did you come to the EFA shootout this weekend?

NoGo

iTrader: (2)

Unfortunately, no. I haven't been able to make it down to the shop for a while either. I recently changed jobs and took a think tank position (engineering group) behind a desk........ less travel, but much much less time off.

I literally had to blow the dust off of my tuning laptop, so I have some catching up to do. I'll be on the boards more often now to help with the 'old school tuning methods' questions, and learn a bit about how much SD tuning has taken off. It is amazing how far it has come. I remember when it was just several shops around the US and the Auzzies performing the 'top secret' SD tuning. The LS1 tuning community has really advanced in the past year or so.

jimmyblue

iTrader: (11)

You need to get the speed density tune right to
have proper low RPM and transient-throttle fueling.
MAF or no MAF. Some people want to go SD-only,
they have their reasons. The MAF is not a bad
instrument and if you calibrate it right it has better
fidelity against environmentals and mods, with no
further fiddling, than the speed density alone. The
restriction aspect falls away when you go to a
descreened 85mm (but, see calibration). Not that
most of us are MAF-limited anyway.

SD+MAF = belt+suspenders; some folks are just
looking for the proper leopard loincloth, is all.

MrDude_1

iTrader: (4)

*points to avatar*

i just try to get everything working like it should...

M_T_0

SD tune works and will give you a car that is easer to tune while doing its job under most conditions with no problems. the MAF + SD tune is the belt and supenders approach and wile more trouble to tune correctly will give you that stock drive it 100k miles and not look at it setup that I am looking for. If you are going to tune it all the time then I would look at the SD setup and you may save some tunning time.


More Than Zero

Gary Z

This misconception seems to be spreading. In general, it is the VE table that needs calibration after the engine is modified. When the VE table is correct you will probably discover that the MAF is not accurate but modifying the engine does not change the MAF calibration.

Y2K SS

iTrader: (1)

Thanks for asking the question. I was just about to do it myself. HORIST in all his wisdom has tried a hell of a lot to enlighten me but being the dumbass that I am I just cant grasp it at times. Or more like I just get frustrated because Im still tuning it lol.

This is what I get from the answers that I saw. Basically in newb terms.... tuning it in SD and then calibrating the MAF is like a "you scratch my back I scratch yours" kinda thing. They both support each other. The SD is a primary tune and the MAF will help out in times of .. lets say shitty weather. YES... NO... HELL I dont know. Tell me if thats it in a nutshell.

MrDude_1

iTrader: (4)

the VE table tells the computer what the engine should be doing. it CAN calculate fuel from that. just like most GM EFI systems since the late 70s.

the MAF just measures air going thru it.. but if you know the air going into the motor, you can calculate fuel from that.


the computer (when in stock mode) uses a combination of both... if you tune and tweek both to be accurate, you'll get best driveability and fuel economy... if you leave it in SD.... eh, you still probly wont notice much of a diff.

NYSS Guy

iTrader: (1)

okay, now to confuse things further. I just tried to order HP, and I saw there are 2 options for SD. Either 1 bar, or 2 bar. What's the difference? Is it worth it to go to the 2 bar?

MrDude_1

iTrader: (4)

2 bar is for forced induction cars (turbo, supercharger, ect)



atmospheric pressure at sea level is 14.7PSI or 1 bar.

stock, you have a 1 bar MAP (manifold absolute pressure) sensor it measures from absolute vacuum to 14.7 PSI absolute ( aka normal air pressure at sea level)

a 2 bar map can go 14.7 PSI above that... aka 14.7 PSI of boost at sea level...


make sense?

NYSS Guy

iTrader: (1)

I do understand that, but is it necessary for me to order this upgrade? Can you do all the tuning I need to do at 8 psi, without the SD? Maybe my problem is that I don't fully understand the benefits of it. Is it something I can add at a later date?

slow

iTrader: (7)

2 bar SD is useful if you can't get maf that will read the airflow your moving.

If your maf is not maxing out, I don't see the benefit of going to 2 bar, but my opinion of the maf is good

Ryan