shovelhead73

I put together an LS2 with AFR 205 heads, a 230/232 .580/.590 114 degree cam, fast 90 with the stock DBW throttle body. I bought an LS3/LS7 blade MAF an installed it into a 4" intake I had fabbed up. Jeremy @ fasterproms did a bench tune and got it close. The motor idles fine and pulls great above 3000 rpm. The problem I'm having is from idle up to 3000, it runs rough, backfires and feels like it wants to cut out until the revs pick up. Is it worth spending the bucks to get it dyno tuned with the blade MAF. Go back to the 85mm stock MAF, least desirable option, must re-do the intake or ditch the MAF and go with a speed tune. I plan to drive it reguarly, is there any disadvantge to gas milage or drivablility with a speed tune, or is the MAF the way to go.

VortechC5

iTrader: (6)

When you switch to the blade style MAF you have to change the MAF table so that it will work right. Was this done?

Here are the values for use with the Power MAF. It might work as a starting point.

http://www.powrmax.com/PowrMAF100%20Tables.html

tektrans

iTrader: (23)

If you're gonna drive it regularly the maf tune is the better way to go imo. This way the maf can adjust to temp/air changes and will idle and drive better.

shovelhead73

Yes, Jeremy @ fasterproms said he loaded a new table. Thanks for the link, I'll ask the tuner to send me a copy of the table he loaded. I've read mixed reviews on this site about using a 100mm MAF with the older computers, the LS2 came with the ECM from a 2006 GTO. Do you think it's worth going forward with the 100mm MAF?

VortechC5

iTrader: (6)

I am running a 100mm MAF on my 02 C5 and it runs fine. I started with a table that is real close to the one in the link.

69LT1Bird

iTrader: (1)

Me too, mine is working great.

SweetS10V8

iTrader: (4)

Most of the time below 4000RPM your engine runs on a hybrid of MAF and VE. Then MAF only after 4000RPM. Your VE might be way off and causing some issues along with your MAF tune not being as correct as possible.

Jontall

I never have problems with my speed density tune. I was hesitant to do it at first, but now I realize that I should have done it sooner.

redtail2426

iTrader: (10)

a speed density tune takes a little more time and patience to do,mine is speed density and i do all my own tuning on my car.since i can tune it pretty much anytime i drive the car my SD tune is spot on,with throttle response and idle that cant get any better.

ramairroughneck

iTrader: (35)

I dont think a 85mm maf is a restriction on your combo. The effort your putting fourth cant be worth the miniscule gain. Youve got a great combo with the 205's and street cam. Dont see it needing any more than the 85mm maf. Tune for the smaller maf and enjoy.

carlrx7

try it in a 3.5 in tube? it will increase the flow across the sensor

LSWNDR

I'm on speed density as well an it runs different everywhere... I don't think runs bad but it really seems to run like **** alot more than good so i am actually thinking about running a ABCO MAF. I'm running a big camshaft an going single plane eventually with a 4150 though so i'm thinking about sucking it up an dealing with it.

CamaroSS22

iTrader: (1)

I ran speed density in my camaro from florida to texas and back with no problems. I got close to 27 mpg with an ls7 and big cam, it changed very little. The o2s should pick up for any changes due to weather, as long as the tables are close they should make up for the changes.

Tyler valo

iTrader: (3)

I have the exact same issue you do on my 418, "idle up to 3000, it runs rough, backfires and feels like it wants to cut out until the revs pick up" except I get in the powerband around 2500. I'm on a MAF tune, my tuner said going with a different gear (I'm on the stock 3.42) will help alot since my cam, 251/258 .625" 114lsa, has a high powerband.

69LT1Bird

iTrader: (1)

I think you need someone else to look at your tune.

Silver408z

iTrader: (1)

I have been told big cams like/need big gears but I dont think that is what is causing your problem. I would have the tune checked before gears done.

hymey

I would go the speed density with a full cos from efilive. Its heaps better.

Tyler valo

iTrader: (3)

I plan to make a trip up to VA Speed this summer to have him re-tune it.

shovelhead73

Found my problem. It wasn't the tune. I had the O2 sensor leads reversed, stupid mistake but I didn't label the connectors correctly when I modified the harness. The motor runs sweet, drivability is even, motor spins freely, and pulls hard all the way to 7 grand. What a blast to drive. Thanks for everyone's help and responses.

edcmat-l1

iTrader: (10)

I didn't tune it previoulsy did I?