NickcZ28

iTrader: (9)

Please in lighten me!!!
Does it make more power ???drivability??

WS6FirebirdTA00

iTrader: (33)

no drivability problems, pro....dont have to mess with the maf. you CAN make a few more poines if you tune it right and get the maf out of there and replace it with a larger pipe. i did it for ease of tuning and i felt my car ran the best like this

WS6FirebirdTA00

iTrader: (33)

also i have been in SD since March without issues thus far. and i see absolutely no changes based on temp or humidity, at least no more than is acceptable with a MAF +/- 1 or 2

777

iTrader: (21)

So why would anyone run their car with a MAF?

WS6FirebirdTA00

iTrader: (33)

personal preferance i guess, and different cars tend to act different to SD, i dont fully understand it unless there was just somethign i did that others didnt, or the other way around. i just like the idea taht there is one table for fueling instead of 2 fighting each other. i got my fuel trims dialed in in 30 deg weather and they didnt change in 60 deg weather and i tuned the cam when it was about 90 or so and the temps have gotten to about 65 and i still see no change in the trims. i am in the process of doing this on a friends car so i will beable to tell even better once i can play around with his tune.

777

iTrader: (21)

Hmm...I would ask Jeremy to do it for me, but I don't want to spend anymore money.

slow

iTrader: (7)

Easier to tune, adjusts to all weather conditions, Set it and forget it. Allows for the use of dry n20. Much easier to get WOT fueling dialed in and consistant for all weather conditions.


Ryan

WS6FirebirdTA00

iTrader: (33)

put it this way, i was at the track as it cooled through the day and my runs were thousands of a second off. so the car stayed really consistent

NickcZ28

iTrader: (9)

cool thanx guys I guess SD is not a bad idea....

MeentSS02

iTrader: (11)

SD is NOT a bad idea at all. There are some people that have a harder time getting their MAF in line than others. Theoretically, the MAF should help anchor the tune. That is if you can get it in line. With HPT 2.0, you should be able to set up a AFR% difference histogram with the MAF (much like you can do with the VE table now) to get it in line.

As long as you monitor your trims often (I'd say at least once a week), SD is perfectly fine. My car ran GREAT in SD open loop, but I didn't get a chance to try SD closed loop.

SSpdDmon

iTrader: (10)

When I went to tune in SD, I turned off a bunch of things like P/E, LTFT's, DFCO, Closed-Loop, MAF Fail Freq, MIL lights, Cat Overtemp Protection, etc. What do you have turned off while driving without the MAF??? Just the fail freq?

WS6FirebirdTA00

iTrader: (33)

i DID have all that turned off but when i tuned i turned nothing off but dfco for the first tune then turned it back on. the maf of course was shut off and the cat stuff because i dont have them. pe, ltft were all on. and its working perfect fo rme

Another_User

The only thing I noticed is that SD does not like a lot of overlap in a cam. It causes low rpm bucking during takeoff.

Silverhawk_02TA

I ran in SD for a long time, and I had no problems with it whatsoever. I finalized my tune in 40 degree weather, and even when it hit over 90 here my STFT's (my LTFT's are disabled) pretty much stayed the same. However, there are some things that the SD calc doesn't take into consideration, like humidity, which can throw off fueling, but that was a non-issue for me out here in the desert.

Also the IAT sensor reading plays a big role in the SD calc, so if it is reading a temp different from that of the air actually coming into the intake, your trims will suffer. For example, if I'm sitting in traffic, due to the lack of oncoming air my intake path (and in turn the IAT sensor) gets hot from the underhood heat from the engine. So, the SD calc thinks hotter, less dense air is coming in the engine and pulls fuel accordingly. Then the O2's read a lean condition since the actual air temp is cooler then what is reported by the IAT sensor, so it kicks the STFT's positive to compensate. Under MAF operation, the IAT sensor plays a much smaller role, so the fueling is much more tolerant of IAT inaccuracies.

I had tried doing a workable MAF tune a few times, but I'm too lazy to do it by hand, and redhardsupra's spreadsheet never got my trims closer then +/- 10 for whatever reason. But using the new MAF calibration spreadsheet that soundengineer did, I've got my MAF calibrated to the point that my STFT's are just as good as they were when I was running SD, and without a whole lot of effort.

People seem to have different levels of success with SD. It worked great for me, but some experience significant fueling changes as weather, temp, and altitude change. Calibrating the MAF also takes a bit more work. All this being said, the MAF reading (which is filtered by the SD calc) is a far more superior and adaptable way to set fueling then SD alone.

WS6FirebirdTA00

iTrader: (33)

ive got the f13, dont know if you consider that a lot of overlap or not but i dont have any low rpm problems really.

i wonder if the IAT sensor was put in the pipe where the maf was if that would help out somewhat with the fueling??

Silverhawk_02TA

I had no surging or bucking once I finished my tune with a Torquer in SD.

I imagine with the IAT sensor moved further back down the intake path and closer to the engine it would be even more susceptible to getting heated up. I imagine simply insulating it fairly well would have the biggest positive effect.

Another_User

I think relocating the IAT to the intake manifold would help a little, and I think that somebody needs to try a restrictor mod on the MAP sensor. I have heard of it being done specifically to try and prevent irregular MAP readings due to overlap.

Silverhawk_02TA

An interesting idea, but I think any modification to the MAP sensor to "restrict" or desensitize it to rapid changes in pressure due to a high overlap cam at low rpm would also cause it to react lazily to all MAP changes, which would be quite detrimental to overall performance I'd imagine, at least as far as SD mode is concerned, since it relies so heavily on correct MAP values.

Of course, the closer you could position the IAT sensor to where the air enters the cylinder, the more accurate a reading of true air temp you will get, and hence better fueling. The problem becomes isolating it from the heat of the engine, which will heat the sensor and throw off the temp reading. This is why the engineers place it fairly far forward on the intake path. Because of this, the PCM also has a table that filters the IAT value according to ECT, to compensate for the air heating up as it travels along the intake path and through the intake and cylinder head to the cylinder. So, if you did reposition the IAT either closer to or further away from the engine, this table would require tweaking.

russell

My trims are about the same whether I'm in SD or not, so the VE and MAF tables are right, but the car runs noticably better with the MAF, it even sounds different. (and I do copy hi octane to low octane in SD !!!) . Maybe the PCM does something else in SD ??

HumpinSS

iTrader: (1)

I have and fm13 on a 110 and no bucking here