dre2013

iTrader: (7)

just bought a car, 355 lt1,p+p heads, cc503,ewp,1.6,LTs,ORY,58mm tb,edelbrock airgap IM, etc...pretty much all the boltons. it has a 4k rpm miss that i'm trying to track down, and some ppeople say it could be the granatelli maf that is on it. I see they are selling for a decent price on ebay, should i sell it and throw on a stocker? does it really add any horsepower? Thanks,
James

96capricemgr

iTrader: (1)

It can temporarily add HP by falsly reporting airflow to the computer leaning out the AFR because stock the WOT AFR is rich. Can also be learned out by the computer because at part throttle it monitors AFR and compensates and if it sees lean it will add fuel at WOT too even though it can not monitor AFR then.

Same power and more can be had through programming. Careful thorough tuning can make a Granateli wrk OK but it is money wasted because your setup is well within the capabilities of the easier to tune for stocker.

kinglt-1

iTrader: (26)

If the maf was tuned on the car then putting a stock unit on would be a downgrade. I was considering putting the stock one back in after hearing all the negatives about them. Most people that have poor results with the granatelli are just throwing them in on the stock tune and in some cases are losing power over this.
The 4k miss you are experiencing is prolly the plugs or wires and even maybe the opti!

jasonisdn

iTrader: (1)

i'll vote opti, if the miss also happens at WOT @ 4000rpm

LM97Z

iTrader: (4)

I doubt its the MAF, like said, its most likely ignition related, now i run the Granitteli unit, its been on the car for 4 yrs., it works fine, no issues with it, i agree, if you don't tune for the Granitteli, it will not work right, i'm also running a hypertech, there considered junk too, mine works just fine, in your case though, i'll bet its a week plug/wire.

dre2013

iTrader: (7)

the car definetly needs to be retuned..everything on the car is new, motor has 6k,opti 1k, wires 500miles, and the plugs have about 200 miles on them, but are fouled..im not driving it until it gets tuned, probably about a week or 2..

BLK,97,T/A,M-6

does the car miss at 4k when you are sitting still? Or is it only when you are moving? I have heard people experiencing a missfire caused by the plug wires arcing off of the LT's (due to wind). Try looking into that before you touch the opti....no sense in creating another problem.

TheDon619

iTrader: (4)

sounds like a tune id check the plugs and wires anyway, but get a tune on it. fouled could be opti or being to lean or to rich.

dre2013

iTrader: (7)

mainly only when the car is driving, at WOT..ive tried to do it with the car in neutral or with the clutch in, and it doesnt do it..opti is pretty much new btw, has about 2k miles on it, and is an msd unit

jasonisdn

iTrader: (1)

yeah i had 2 new msd optis. 1 bad out of the box. the other went bad in 4 pulls on the dyno. i swore those pieces of msd crap off. of course i had 1 bad new opti factory oem piece and another new oem drop the rotor screws out. i hate optis.