Speed Density Tune Vs MAF Tune
Thread Starter
Staging Lane
Joined: Mar 2007
Posts: 65
Likes: 0
Speed Density Tune Vs MAF Tune 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.
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
Here are the values for use with the Power MAF. It might work as a starting point.
http://www.powrmax.com/PowrMAF100%20Tables.html
Thread Starter
Staging Lane
Joined: Mar 2007
Posts: 65
Likes: 0
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?
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.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
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.
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.
TECH Regular
Joined: May 2008
Posts: 460
Likes: 0
From: St.Louis Missouri
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.
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.
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.
I think you need someone else to look at your tune.
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.
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.
Thread Starter
Staging Lane
Joined: Mar 2007
Posts: 65
Likes: 0
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.
