What are, if any, the limitations of the stock MAF sensor? At what point, do you need to upgrade?

I haven't used the stock, throttle body mounted MAF sensors on any of my turbo 3800 builds. I've instead used the 3.5", 3-wire LT1/early LS1/Vortec MAF sensor. I think we came close to maxxing it out on a Fiero that was running 11.3 sec in the 1/4 mile @ 121 mph. I've always installed them as close to the throttle body as possible as well.

-ryan

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OVERKILL IS UNDERRATED

Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com

So with that, I would assume the stock 3800 MAF will max out sooner, or be the same as the ones mentioned. What MAF would you use if you were going for high boost with a 72mm turbo?

I've never had good luck blowing thru the stock 3800 MAF sensors (the ones that install into the throttle body). Could have just been the type of MAF/throttle body I was using though (which have all been F-body 3800 N/A, since that was the intake we were using). Had some problems with this particular MAF setup reading airflow correctly when boost was applied, even back in the day when my engine wasn't making a whole lot of power with the turbo (when I first put it together). I installed a 3.5" MAF from an LT1 and have never had a problem since; and since then I've used it in a couple of other turbo builds and never had any problems with it. There are all kinds of aftermarket MAF sensors available if you need something that has more flow capability than OE GM units, and I think you can even mod the stock ones by soldering a certain value resistor across the internal conductor bars so they'll give you more headroom (if you are in danger of maxing it out).

I've never tried using an L67 throttle body and MAF in a blow-thru turbo application so I can't tell you if it works; (it may) nor can I tell you when it maxes out.

I have a stock '99 throttle body & MAF that has been modified. You can also use an AFC to adjust the resolution.
http://shop.zzperformance.c...Fuel-Controller.aspx

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Turbo 3800 E85 5spd spec5
11.54@132.7

[This message has been edited by Justinbart (edited 12-06-2011).]

Yea, I snagged a Fbody 3800 Throttle body from the junkyard this past saturday and dismantled it with the intention of boring it out, but came to the realization that it will be inadequate for what my intentions are, which is also what made me think of looking into the stock MAF limits and what options are out there.

found this one on summit...any thoughts?

http://www.summitracing.com/parts/AAO-AB-DBX97B/

the original one off of my 99 suburban is working might good - for free (they are cheap to buy too)

quote Originally posted by ricreatr: the original one off of my 99 suburban is working might good - for free (they are cheap to buy too)

Ya know, after seeing some pics of t-bodies that people are using, I have often wondered if the chevy/gmc truck t-bodies would work (I was thinking the 2000-2004+ year range (before drive-by-wire). They look very similar to the larger ones people are using, and a person should be able to snag one off a 6.0L truck engine for pretty cheap. Grab the t-body and maf sensor, relocate maf to the intake tube? Thoughts on this?

[This message has been edited by 1fatcat (edited 12-06-2011).]

I would probably give that a try before buying a $400 aftermarket one.

Just remember that we are pushing air through the TB, not pulling, with a turbo. The 3800 TB is more than large enough. It would take a hell of a motor before you would see pressure differences on either side of the TB at WOT. Your intercooler will be a larger restriction than the TB will ever be.

I like to keep things simple. That AFC controller would be the best thing.


My MAF is modified by having a piece of metal partially blocking the metering orifice. It takes a a little bit of guessing at first to tune it but Scott had it dead nuts after a few adjustments.

^^^All part of keeping costs down in a swap.
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Turbo 3800 E85 5spd spec5
11.54@132.7

[This message has been edited by Justinbart (edited 12-06-2011).]

I will definitely keep that in mind as an option as well. Thank you.

quote Originally posted by Justinbart: Just remember that we are pushing air through the TB (with a turbo), not pulling. The 3800 TB is more than large enough. It would take a hell of a motor before you would see pressure differences on either side of the TB at WOT. Your intercooler will be a larger restriction than the TB will ever be.

Very true. When forcing air thru the throttle body, size (diameter) of the throttle body becomes less of a factor vs. an engine that isn't using boost to force air thru the throttle body. A good example of this is what they guys in the Buick GN community are using for throttle bodies. There are 3500lb+ cars running 10's and faster in the 1/4 mile using throttle bodies that are SMALLER than the smallest stock 3800 Series 2 throttle body.

quote Originally posted by ricreatr: the original one off of my 99 suburban is working might good - for free (they are cheap to buy too)

The LT1 maf is great up to about 400whp.

quote Originally posted by Justinbart: I have a stock '99 throttle body & MAF. http://shop.zzperformance.c...Fuel-Controller.aspx

X2 Keep it simple.

I will soon be joining the Turbo 3800 crowd and they all WILL know my name.
Bow Down to the new speed king... ...LOL

I'm running the camaro throttle body and intake manifolds, hasn't kept me from making enough power.

I am running an LQ4 MAF. They can be found for around $50

has anyone ever eliminated the MAF and converted to speed density?

quote Originally posted by tampalinc: I am running an LQ4 MAF. They can be found for around $50

They dont offer much more than 320whp handling without getting dangerous.

quote Originally posted by tampalinc: I am running an LQ4 MAF. They can be found for around $50

According to ZZP "Non restrictive in applications to over 500WHP and increase HP in application making over 300WHP"

http://shop.zzperformance.c...-MAF-Sensor-kit.aspx

[This message has been edited by nosrac (edited 12-07-2011).]

quote Originally posted by nosrac: According to ZZP "Non restrictive in applications to over 500WHP and increase HP in application making over 300WHP" http://shop.zzperformance.c...-MAF-Sensor-kit.aspx

ICCU, mini AFC or custom PCM programming needed for proper fuel calibration.

quote Originally posted by 1fatcat: Ya know, after seeing some pics of t-bodies that people are using, I have often wondered if the chevy/gmc truck t-bodies would work (I was thinking the 2000-2004+ year range (before drive-by-wire). They look very similar to the larger ones people are using, and a person should be able to snag one off a 6.0L truck engine for pretty cheap. Grab the t-body and maf sensor, relocate maf to the intake tube? Thoughts on this?

actually my 99 burb is still the ooolldd body style (used to have 5.7) and maf. BUT, now that you metion it, i am using that very throttle body. it works great, and with a couple new holes, bolted directly to my camaro intake.
. . . and it was FREE! seems gm did a recall on the original 5.3 throttle body WAY back (for sticking throttle) and i ended up with a couple "laying around".

So, I was looking into the double roller timing chains and saw about the necessary removal of the balance shaft. How many have done this and what was the result?

quote Originally posted by Genopsyde: How many have done this

Probably thousands

quote and what was the result?

it works.

So, no catastrophic failures or premature engine wear due to unbalanced harmonics?

From what I read... the thing was added to the engine to make it feel more 'refined' being that it was a 90* V6 and really had nothing to do with longevity.

Old 3.8s are tanks and never had them...

[This message has been edited by carbon (edited 12-16-2011).]