Shinobi'sZ

My car is currently tuned with the old style 97-2000 Corvette MAF. It is the small one with the screen and the IAT sensor located close to the TB. My car came with the standard LS6 MAF which is an 85MM MAF. The place that tuned it last told me they use the Small MAF because it does not surge with Turbos and easier to tune than the bigger MAF without the screen..are they full of ****? I would like to put the regular MAF back on just thought I would get your opinions and thoughts.
Thanks
Kevin

MIGHTYMOUSE

iTrader: (59)

use the biggest one you can find that you KNOW the hz graph of... that turns out to be a bone stock maf, or an lt1 stock maf if you can come up with one.

if you know how to manipulate the stock computer to report more than 512 g/s then it doesnt really matter what maf you use.

Black LS1 T/A

It is easier to idle with the screen. I was able to tune with a large MAF better than a small one, in my experience, because the electronics were extended to allow me to use the full 511.99 in the tables. That gave me an RPM window extended from 4800 RPMs to a little over 5800 RPMs.

I like that I was able to keep it from maxing out almost to 6-grand.

I don't think it's the size that makes their tuning easier (if they are talking driveablility tune), it's the screen. It won't stumble so much coming to a stop at a light, and it will idle easier. I got the same affect by moving my MAF to before-blower position AND it truly IS easier to tune because the inherent PCV leak of the TB routed to the inlet hat does not affect the air metered by the MAF (resulting in higher LTFT's).

[ducks head]

Anyway... I think I'll have a whole different bunch of tuning issues with the boost referenced regulator and different fuel system setup.

kp

iTrader: (34)

I'm working with a C5 with the TTi twin kit on it now and I am using a descreened small MAF, mostly because thats what the car hasd on it. The f-bodies have the MAF a couple inches in front of the TB so w/o the screen (and sometimes with it) it causes all kinds of odd idle/part throttle issues with a supercharger/turbo that cant bypass enough, but thats a non-isssue with the C5 from what I have seen. The size of the MAF really wont matter much on the pressure side but if whoever is tuning on your car prefers the old MAF and you are happy with the numbers dont fix what isnt broke..

I have the MAF recalibrated and PCM rescaled to the max and it reads pretty nice up to 6200rpm, thats with 11psi or so..

S_J_H

I moved my 85MM maf to the pressure side. With a Mondo bypassing to air way before the maf, idle and part throttle are perfect. No surging or anything funky.
But at WOT the readings are very erratic and all over the place compared to the smooth graph I would get when it was draw through. Although fueling seems to be fine as the PCM must have some sort of smoothing or filtering for it's output.

Shinobi'sZ

Good responses.
I too (as you probably noticed) have the TTi kit..base boost is 13lbs (a small drop off occurs when the internal wastegates open, this causes a momentary drop to 11.5lbs then restabalizes to 12lbs at max rpms). My car drives like a stock Z06 with a Comp Xer 224 cam in it. I am very happy with the idle and drivability...I was mainly curious if I had anything to gain by switching to a bigger MAF without the screen. I am pretty sure the stock Z06 MAF (85mm) is the same as the truck MAF. If it doesn't make any difference I am just going to leave the small MAF in the setup and change the fuel injectors to some Mototron 60lbers.

PurEvl

iTrader: (2)

I used stock MAF but had to run two bypass valves, cause with one it was surging and driving like ***

CamaroSS1618

iTrader: (4)

I have a SLP 85mm MAF, and I do notice my car does surge and struggles to idle sometimes. I thought it was because of the Dyno tuning, any suggestions on what I should do? Remove the screen? Relocated it? If I relocated it will I need to redo the tuning?

kp

iTrader: (34)

I have seen a little gain by removing the screen but in your case I dont think it would matter much, the truck MAF is the same as the Z06 I think but calibrated a little different and has a screen. I have seen a tiny boost increase removing the screen but that will really mess with the tuning so if the car is right I would just leave it.

I'll get some dyno numbers soon on this car, it blew out the factory airbridge so that ended things until the new one comes. It is the TTi manifolds/gates/intercooler with home built piping and intakes with a 9.5:1 forged shortblock but I forget the cam 228/224 581 115 if I remember. Its SR71 from corvetteforums car..

Shinobi'sZ

Kool....which Turbos did you get with the TTi kit? I had the final release version I think after Phil from Detroit Speed Works sent back some final data to George. I got the specs.

Black LS1 T/A

I actually ran consistently about a 10th faster (8th mile) with the screened stock MAF over the Descreened MAF, but that could be any number of things not necesarily related to the screen. For all I know, I may have retuned it and it ran better. It just wasn't worth the idle characteristics for me to dik with it.

kp

iTrader: (34)

Dont remember but I do remember he didnt buy them until your car was finished, I think its a t3/t4 hybrid..

PurEvl

iTrader: (2)

Take the SLP out and punt it like a football and pick up a stock one and put it in as is.

Shinobi'sZ

Let me know what your results are. I had my CR at 9.67:1 and was getting some detonation so I lowered the CR.

kp

iTrader: (34)

I think he is at ~9:1, we'll get it on the dyno one day next week - my trans just crapped out tonight so I'll have enough time to get his dialed in..

QuickSilver2002

I thought the entire reason people use the older /smaller metal MAFs was becase they are calibrated to put out 512g/s at the max frequency the PCM can read. The newer MAFs output the same frequency at something around 428 g/s (450 descreened z06 style).

KP, what did you mean when you said you had the maf recalibrated? Are you talking about a MAFT.

kp

iTrader: (34)

No, just the the resistor thing... I'm pretty sure the newer MAFs will read as high as the old MAFs, honestly havent messed with a newer MAF that has been maxed out so I cant say..

Shinobi'sZ

I have heard the older MAFs read more gpm at the max frequency too, but I don't have anything available to reference. It is probably over on the tuning site though, I will do a search. One thing is for sure with FI regardless of which MAF is being used..they both get maxed out. I will say my car is as smooth as a stock car..except for the little lope from the cam and little more valve train noise.

whitt1

I'm planning to rescale my PCM and my programable ProM MAF to allow for the additional flow to accomadate my 408 Radix supercharged combo.Does anyone have experience with this type of calibration?If so I would really appreciate any input on the subject.

QuickSilver2002

Resistor thing? I have not heard of this, can you elaborate. I guess this would have to be somewhere within the internal electronics of the MAF, since a resistor would not be very useful for directly conditioning the external square wave signal.