jimib

Just making sure everyone still agrees that removing the honeycomb is a bad idea. The topic was touched on alot more often 2 years ago on here and most people said no no no. And I think that obviously became general consensus and has not been talked about much since. I know that it definately isnt hurting in there, and I would much rather leave it in there myself. Long story short Ive been helping a friend of mine tune for a couple months now only to find out today that he hasnt had his honeycomb in for a very long time. The car was originally a mail in dynoflash. When we first hooked the wideband up it was pegged 10.0 (aem) I have allways heard that Dynoflash is still pretty rich so chalked it up to that. I first tuned with safc2 and leaned it out as much as 14% to get a pretty steady 11.3-11.5. Since ditching the safc2 and going straight ecuflash its been a alot more difficult to get a steady afr. He also has some driveability issues (part throttle low load especially), and not the best idle. Also afrs in the 10-11 range during cruising... Not exactly stoich... In the mean time he has been fighting IC piping leaks, faulty Bovs (both leaking and sticking) So I thought alot of the driveability issues would be solved with that. Now he has a Forge bov, Buschur deluxe FMIC, upper and lower piping etc. Everything is nice and tight. But holding steady part throttle at low loads its real jerky. The bigger problem with attributing the honeycomb to the driveability, that is that it did not used to do that with the stock bov and stock upper. The car has ran 12.46 @109 on race gas 25psi before upper ic piping and bov on the safc2 tune. Since ecuflash tuning and upper ic/forge bov it has gone 12.52 on pump gas and 22psi.

Just for reference:
03 GSR, 10.5 hotside ported, stock x mani ported, Buschur delux FMIC with upper and lower pipes, Forge BOV, no airbox ebay filter, ebay o2 housing, walbro255, 3" tbe

So im not sure if Im looking for someone to tell me that if we get a honeycomb in there that it will fix all driveability issues and be much easier to tune.. Or if im looking for someone to tell me ah it doesnt matter really.

Fire away...

l2r99gst

iTrader: (2)

Removing the honeycombs dramatically alters the maf calibration curve. It will affect low airflow a lot more, percentage-wise, than higher airflow situations.

One the MAF tables are understood a little better (I'm messing around with them a little at the moment), you should be able to recalibrate the MAF for a 'hacked MAF', as it is called with the honeycombs removed. This was a popular mod on DSMs to improve the max airflow that the MAF was capable of.

But, the Evo MAF can read pretty high, even with the honeycombs still in there, so I would HIGHLY suggest to put them back in. It will solve all of your problems and you won't have to take out fuel as a band-aid fix. If you really want the removed, wait until the MAF tables are completely understood, then you can calibrate for it.

If you leave them out, you have no way to fix your closed-loop fueling, since the MAF tables are the only way to do that when hacking the MAF.

Eric

AlwaysinBoost

iTrader: (17)

i've had my MAF screen out for a couple of months now, its not by choice though. I sucked it in while running a larger turbo.

anyway just like Eric said above your low speed driving will be affected the most. sometimes when coming down from highway speeds the a/f will surge to 16.x:1 but it settles down after a few seconds.

I don't notice any difference @ WOT, infact the last 3 or 4 times I was at the track I didn't have the screen in and noticed no decrease in performance.

BTW, if anyone has a stock MAF for sale with the screen in good condition shoot me a PM, lol.

MalibuJack

iTrader: (5)

Yeah, the hacked MAF does all sorts of weird things that affect drivability. Technical explanation aside, it fouls up the metering at low airflow and makes it real difficult to tune for drivability.

I would strongly suggest putting it back in, as it really doesn't affect the max airflow in a stock Evo MAF. You will hit an issue with the meter itself (the karmann signal begins to read erratically and of course, the meter becomes a restriction above that point anyway so removing it will do very little to help you.

C6C6CH3vo

iTrader: (9)

Removing it will cause the MAF to malfunction and actually cause a drop in flow, thats right - streamlined air flows much faster than turbulent

I use extra honecombs -



The OEM honeycomb does it's stuff with the MAF but also provides an opportunity for some velocity stacking with an added SS honeycomb at the turbo inlet.

At 22 psi, I flow the same air with it as I do at 26 psi without it.

I will have some comparative datalogs this Feb done back to back

JohnBradley

iTrader: (30)

C6- Very interesting proposition. I am looking forward to your logs/data when you get a chance. I am curious where you obtained the the honeycomb, is it just an old MAF or something else?

C6C6CH3vo

iTrader: (9)

It's made from stainless (316 I think),

It was given by diesel power machinist/beer bottling company so long as I provide some airflow logs. I should have WB evoscan datalog capability by Feb (need a laptop and LCI Bosch) to run these tests.

I have a feeling this simple configuration made the 16G VIII more efficient (less taper) and increades it's flow volume and velocity (MBC spring holds 4psi less)

jimib

Thanks for the info. I guess another maf is the way to go. I thought I did see on another thread that you could get another honeycomb.. not sure how you would fasten it in there..

C6C6CH3vo

iTrader: (9)

You can probably find a MAF for $80 in the WTB pages, but prices and avilability are changing because less people are going standalone or GM and using ecuflash instead. A year ago I found one for $70 because mine was dented

You basically have to destroy the MAF ($600 new) to get the aluminum honeycomb out.

nothere

iTrader: (23)

C6C6CH3vo,

very interesting, you are not using the stock intake tube either. I know everyone has jumped on the conclusion that the stock tube did some post meter miracle.
But I digress,

So your thinking is, the air coming out of the second honeycomb is smooth and thus more directed? No swirls and eddies to fiddle in the blades? It does look counter-intuitive, putting in another restriction.

Maybe it could be argued the smooth walled intake pipe needs the other honeycomb while the corrugated stock unit self tabulates the air. -- I know, slightly different concept.

Regardless hope to see your results.

MRadjahoe

iTrader: (32)

If u want to run high boost on a big turbo I heard using glue on the edges will help not let it get sucked it.

X350ZOwner

iTrader: (5)

I accidently dropped a screwdriver into my stock airbox while putting in my HKS hiflow drop in filter. There is some dents and a small hole in my honeycomb. I noticed that my car chugs in low low rpms in 1st gear. Do I need a new MAF? Also I was thinking about buying the HKS super Suction intake. Does it come with a new honeycomb? Or am I still stuck with using my damaged one?

JohnBradley

iTrader: (30)

Sounds like I should look for a 1G or 2G MAF then. Those are just sitting taking up space for the most part anymore.

jimib

Well he lucked into getting a good maf with an almost new filter given to him. He had a cheap ebay filter with an adapter. This new maf had the filter that buschur sells to attach right to the maf. Of course the car was immediately a comepletly different car to drive. Much much smoother. Prior to this the car would have very incosistent afrs going thru the gears. Anywhere from 10.5 to 11.5. I just could not get them stable. With switching the maf only im not quite sure how stable they are because the afrs were around 12.8 or so... So that obviuosly made a huge difference. So I loaded the dynoflash map up and the afrs were 10.0 sometimes 10.1 (aem gauge so who knows how rich it was, or stable since it stops at 10) So then I made some changes to the fuel map that where about middle of the road from the dynoflash map and my most current map. Back up to 12:1 +. Split the difference and got it right at 11.6 So I think this is going to make things so much easier I beleive. This is the only car I really have got into the fuel maps for. So im hoping the results of the changes I make are going to be alot more predictable now. I put it back to the dynoflash map until I actually get a chance to really log and make changes. But even with 10:1 it has alot more power down low.

Im just wondering how big of a factor the nice filter made with the afrs going from 11.5 to 12.5. Im sure it was a combo of the honeycomb and the superior filter... We know the honeycomb took the driveability problem away but was it the majority of the whole point + increase AFRs?

One thing that I noticed is still there that may be normal is the difference in afrs if you go thru the gears 1 2 3 4 Vs cruising in 3rd and going wot. It tends to have totally different AFRs that way. Any input? I thought the maf might of changed that but it did not.