Irocss85

iTrader: (1)

building an LS1 but am not sure if it would be worth any HP to get an SD tune at my level. it'll be tuned on a local mustang dyno, which reads low comparativly to other dyno's in the area, so Im not concerned about the final #, just that it runs good and makes best use of what I have, and the best track times possible.
the eng. is an 02 with 6K miles, my own ported heads that flow decent, but not up to pro level. still alot better then stock. anyways, 235/242 LSK lobes 112+2 cam, t56, stage 3 clutch, ported tbody, lid/k&n, hooker longtubes, offroadY, catback, 3:73, SVO 30lb inj (38lb @LS1 press.s?), LS6 intake, stock valves/platinum springs, 11.2CR, 8.3DCR, (milled heads and .040 cometics), 160ts, think thats it.

anyways at this build level, think it would make sense to do an SD tune powerwise and driveablity-wise? from what Ive read, it is easier to tune that way, and gains some HP over a MAF tune.

and, if I leave the maf on, should I port the maf? I have a ported maf on my 95, hell I could even just swap the maf ends on the dyno. Ive heard some people think ported maf's will never be accurate.

Cliff

iTrader: (19)

Chris, I don't think you will need a SD tune as your MAF most likely will not max out with your set up and cam. I would leave the ported MAF off as they can cause lean conditions and they are hard to tune. Oh, by the way I found the company who makes the burrs we were talking about. Good luck.

Irocss85

iTrader: (1)

thanks cliff, send me a link to that company. I havent started finishing the other set of heads yet cause Im too busy still with this current setup to worry bout those. I got them mostly roughed out already. did you see my update to my head flow post? picked up around 5-10cfm through out the range, except the high end. the next set I'll widen the port a bit and see what happens. oh and do me a favor, if you get a chance, send me some pics of the tools you use to measure the inside of the ports with please. havent figured out how to do that yet.

what will max out a stock maf? higher HP? higher rpms? higher flowing heads pulling more air (and making more HP)?

MeentSS02

iTrader: (11)

It would really only matter if you were having a hard time tuning it (part or wide open throttle) with the MAF on there. FWIW, I run full time SD, and I'm just a bolt-on car. I do it for simplicity's sake...the VE table is primarily what controls my car's fueling, so it is pretty much the only thing I adjust anymore.

As for your initial post, the SVO 30 lb/hr injectors are actually 34.6 lb/hr at the stock 58 psi fuel pressure (not 38). SVO 42 lb/hr injectors would be 48.5 lb/hr under the same conditions (providing both were rated at the standard 3-bar [43.5 psi] pressure).

Irocss85

iTrader: (1)

ok cool. thanks for the heads up on the injs. I guess we'll just have to wait and see how things go on the dyno during the tuneing process. in the meantime, I'll find some pipe to make a maf! out of just to have on hand. by hard time tuning, do you mean makeing it idle smoothly, getting any bogging corrected, and so on? lean conditions at part throttle?

thanks

MeentSS02

iTrader: (11)

Yep...anything like that. A big cam like that might have enough reversion to give the MAF a fit (since it only measures airflow...it doesn't care which way it is flowing) at idle/part throttle.

SS4Matt

iTrader: (4)

Chris. i would suggest just leaving the MAF alone. don't pull the screen out of it either, as that's what straitens out the air so the MAF can read correctly. i don't think an SD tune would be beneficial for your dad's car being just a Head/Cam car.

hell you've drove my car and my cam is a little nastier then the one goin in your dads car and it runs/idles/drives just fine! it gets a little bit of "trailer hitch" if your at like 1500 rpm and coasting then go to give it just a bit more gas, but that's about it.

and the dyno is accurate not low i put down 421hp on it when i had my stock injectors maxing out!

Irocss85

iTrader: (1)

hey matt, whats up? I dont know what size your cam is, but I know its on a diff. LSA/ICL then mine, and far as I know mine will idle alot lopier then yours. lots of overlap (agian not sure how it compares to yours) equals (I think) harder to tune and maybe because of the maf and "reversion" is what I was thinking about. Im sure sean will figure it out, just was trying to be proactive and learn for myself along the way ya know?

you get anything done to your car lately? like replace those maxed out inj.s and go for another spin?

moeZ28

iTrader: (7)

Descreening the MAF was one of the first things I ever did when I bought my car 4 years ago. My tuner tuned my car in speed density mode then he turned the MAF back on, after recalibrating it with a program he wrote to match up the tables, and we redrove the car. He said it didnt matter if we left the MAF on, it read perfectly fine. My MAF was one of the most accurate he had tuned, and he has alot of experience tuning LT1 and LS1 cars. The screen is unnecessary.

98SS2836

iTrader: (6)

I would ditch the MAF I tuned my car with both MAF and a SD tune. It drives a lot better with the SD tune Throttle response is better easier to tune ect..

SS4Matt

iTrader: (4)

gotcha, can't go wrong either way really, ...but yeah i got a set of 60# injectors like a week later. thing moves out even better now...it's in the garage now though waiting for the parts pile to increase before it goes under the knife!

yobabiesdaddy2001

iTrader: (20)

I agree here, my car drives better without the maf.

ringram

The Aussies dump the MAF for tune only setups. It stays out from there on!
Ask yourself why Hemi 5.7 v8s all run speed density too.

There is obviously no reason not to. The MAF is a bandaid to cover up a bad tune.

1fastTransAm

iTrader: (6)

IF its a daily driver a MAF is way more forgiving than SD I run SD for a DD but can be a pain at times. Also if you do more changes later a MAF will readjust easier for the AF verse a SD car which you have to go in and readjust the VE table. SD runs off of throttle poss. There is no Horse Power gain for either one. I picked SD cause it looked cleaner. I wont be doing anychanges anyways cause my car is maxed out aside from a bottle. SD is good for a track only car or really high HP cars cause no matter the air you get the same AF once its tunned right.

Irocss85

iTrader: (1)

well, its no daily driver. in fact the car only has 6K miles on it. and thats cause I put 1100 miles on it early last spring for him. I wont be making any changes for a long time. doin the suspension/rear axle when more money becomes available. Im hoping the car will hit mid 11's this summer.

ringram

Actually alpha-n fueling goes of TPS, SD goes off RPM, MAP and VE. TPS does not enter the calculation at any stage.

You are right, there is no horse power gain "unless" the maf is a restriction or you are flowing more air than it can see. No maf = no restriction there.