Getting the most out of your Apexi S-AFC= Stock MAF honeycomb removal - Page 32 - 3000GT/Stealth International Message Center

TurboBob · 09-17-2003, 11:35 PM

Umm, it depends.....

On what, I really don't know (yet).

You usually need to drive for 10-15 mins before the mid and high start to adjust.

B

wizard · 09-18-2003, 09:03 AM

Quote:

Originally posted by TurboBob
Umm, it depends.....

On what, I really don't know (yet).

You usually need to drive for 10-15 mins before the mid and high start to adjust.

B

as long as my 02s are cycling, mine will adjust the fuel trims within a minute (low), the mid and high take about 10mins of driving.

wizard · 09-23-2003, 04:27 PM

time 2 wake up this thread again:

ok, my final conclusion on this setup:

short version: does add some high end power, but low end gets worse b/c of tuning issues.

long version: the turbos DO spool up quicker and hold more boost in 1st gear. I know this b/c my EBC started spiking like crazy (it couldn't compensate for the quick rush of air any more) (HKS EVC IV)... So it does add some more power in the higher RPMs range... but here's the problem: At normal driving speeds, this setup wrecks havock on the ECU trying to keep a stoich condition.
With an ungutted MAS, equal amount of air goes through the middle of the MAS(to the sensors) as through the outside opening. However, with a gutted MAS, if you're at LOW throttle, air does not want to go through those damn honeycombs, and it just squeezes by through the openings w/out the honeycombs. But once you step on the pedal and the turbos start sucking in good amounts of air, then the difference in air movement becomes smaller because air gets FORCED into those honeycombs. Sooooo, lets say you normally drive at 25% throttle and that's what you tuned for... At 25% your A/F ratios are ok, but as soon as you press down on the pedal more, you'll see your O2 trims skyrocket (mine were around 160-165%). and if you drive at lower throttlw... say 18% then the trims drop like a rock (mine were at around 30-40%) this is b/c your MAS is not readind enough air (since air doesn't want to go through honeycombs)... So on average I was seeing my O2 trims going anywhere from 30% to 170%.... (with an ungutted MAS, Those numbers were around 80%-120%) THis means that the ECU has to compensate almost 3x as much for air flowing through the sensors all depending on how much air is being pulled by the turbos. THis is also a problem on my car for open/closed loop, the car hickups like crazy when it's entering/exiting loops.

So in conclusion: It's a nice CHEAPPPP setup if you want quick power at the track, but in my opinion not worth it if you're like me and use your car as a daily driver b/c of the tuning issues.

I ordered my MAF-T setup which should be coming in this week and I'll tell you how that does later.

boostedVR4 · 09-23-2003, 04:36 PM

Quote:

Originally posted by wizard
time 2 wake up this thread again:

ok, my final conclusion on this setup:

short version: does add some high end power, but low end gets worse b/c of tuning issues.

long version: the turbos DO spool up quicker and hold more boost in 1st gear. I know this b/c my EBC started spiking like crazy (it couldn't compensate for the quick rush of air any more) (HKS EVC IV)... So it does add some more power in the higher RPMs range... but here's the problem: At normal driving speeds, this setup wrecks havock on the ECU trying to keep a stoich condition.
With an ungutted MAS, equal amount of air goes through the middle of the MAS(to the sensors) as through the outside opening. However, with a gutted MAS, if you're at LOW throttle, air does not want to go through those damn honeycombs, and it just squeezes by through the openings w/out the honeycombs. But once you step on the pedal and the turbos start sucking in good amounts of air, then the difference in air movement becomes smaller because air gets FORCED into those honeycombs. Sooooo, lets say you normally drive at 25% throttle and that's what you tuned for... At 25% your A/F ratios are ok, but as soon as you press down on the pedal more, you'll see your O2 trims skyrocket (mine were around 160-165%). and if you drive at lower throttlw... say 18% then the trims drop like a rock (mine were at around 30-40%) this is b/c your MAS is not readind enough air (since air doesn't want to go through honeycombs)... So on average I was seeing my O2 trims going anywhere from 30% to 170%.... (with an ungutted MAS, Those numbers were around 80%-120%) THis means that the ECU has to compensate almost 3x as much for air flowing through the sensors all depending on how much air is being pulled by the turbos. THis is also a problem on my car for open/closed loop, the car hickups like crazy when it's entering/exiting loops.

So in conclusion: It's a nice CHEAPPPP setup if you want quick power at the track, but in my opinion not worth it if you're like me and use your car as a daily driver b/c of the tuning issues.

I ordered my MAF-T setup which should be coming in this week and I'll tell you how that does later.

I agree with this 100%. I'm removing my gutted MAF to put my stock MAF back in. I'm ordering the EMS next week.

Gabe92RTTT · 09-23-2003, 05:10 PM

For my purposes I think the mod is ok. I only drive the car on the weekends at night. I am saving for the MAFT though, this just being temporary. Its so unresponsive with the stock MAS.

Innovator · 09-24-2003, 06:58 AM

Did you ever consider removing the center honeycomb?

Honestly guys, this mod has worked perfectly for me, across the board, only at the cost of pulling the bat fuse every 500 miles or so to reset the trims.

I'm not really defending this mod, other than to say some of you are being a little over anylitical about the fuel trims and what they are.

What you really need is a Wideband O2, and you'd see what an excellent job this mod does of keeping the AF exactly where you want it (up top) where it really counts all the way to 7300 rpm..

Down low, just pulling the fuse once in a while does the job.

That is all....

Innovator · 09-24-2003, 08:07 AM

Quote:

Originally posted by wizard
time 2 wake up this thread again:

So on average I was seeing my O2 trims going anywhere from 30% to 170%.... (with an ungutted MAS, Those numbers were around 80%-120%) THis means that the ECU has to compensate almost 3x as much for air flowing through the sensors all depending on how much air is being pulled by the turbos. THis is also a problem on my car for open/closed loop, the car hickups like crazy when it's entering/exiting loops.

.

After that post, I removed the infamous"has to be there" center honeycomb, and guess what? It doesn't have to be there.

Just reduce the low throttle fuel at idle by about 10%, and you no longer will have the issue of the air not wanting to go through the center honeycomb, because they wont be there

The car still idles perfectly, air fuel ratios are perfect, although they needed a little tweaking down low, and the car is even more powerful, because there is one less restriction in the MAF.

Yes guys, the stock MAF read and works fine with ALL the combs removed. It just takes a little finese to tune it.

Try it. You've got nothing to lose!!

wizard · 09-24-2003, 08:57 AM

I was thinking about removing the center honeycomb, but then I read that EVERY single person that's done this had problems w/ it.... I guess its not quite true.... From what I understand, the purpose of the honeycombs is to take the turbulant air coming in and straighten it out for the sensors to read more accurately... So while I never did remove the center comb, I'm thinking it might give me even more problems in the long run than with the side combs removed only.....

How do your trims look w/ the center removed/??

O btw, don't forget the screw at the bottom too, some people unscrewed it and got even MORE air going thoguth...... damn if somebody can set this up well, we'll have flowthroughs!

You know what guys, you know how on the ARC2 87mm MAS, it has that little port going to the sensors..... I think if somebody could make a port like that for our MAF's and put it on a gutted one, We wouldn't have any problems with turbulant air, and still have plenty of room for the air to move, and probably not even have to tune idle to +15%......

umm...... I call royalties!

Gabe92RTTT · 09-24-2003, 09:42 AM

I would remove the center honeycomb and go out and take some logs of o2s and stuff, but the car is kind of appart now awaiting the fabrication of my DSM intercoolers. Once its running I will give it a shot.

The only thing that I have found odd with my trims is the low plunges to 81 at idle, yet my o2s cycle ok. Once driving starts up, it picks back up to ~100. Mid is stuck at 110 and high is at 100. Drives fine, seems fine. Kinda ghetto to have to reset the ECU every now and then, but for my poor ass student budget, its ok for my weekend warrior.

Innovator · 09-24-2003, 02:09 PM

I wouldn't worry about the actual valuse of the trims. If the car is at 14.7:1 at idle and cruise, all is well. If i's way off wack you will get a cel directing you which way to go with the fuel compansation. I can't measure trims on my 95, and the FJO is all I have, and it's been all I need to date.

AF seems smooth and spikeless with all the combs removed.

It doesn't really matter if the MAF measures the air accurately(because the combs are removed?), but what matters is consistancy. The AFC takes care of the accuracy aspect of it.

09-23-2003, 05:10 PM	#315 (permalink)
Gabe92RTTT U2SLOW Join Date: Aug 2002 Location: Albuquerque Drives: '92 Dodge Stealth TT Trader Rating: (37)	For my purposes I think the mod is ok. I only drive the car on the weekends at night. I am saving for the MAFT though, this just being temporary. Its so unresponsive with the stock MAS. __________________

09-24-2003, 06:58 AM	#316 (permalink)
Innovator Blowing hot air Join Date: Aug 2001 Location: Albany NY Trader Rating: (6)	Did you ever consider removing the center honeycomb? Honestly guys, this mod has worked perfectly for me, across the board, only at the cost of pulling the bat fuse every 500 miles or so to reset the trims. I'm not really defending this mod, other than to say some of you are being a little over anylitical about the fuel trims and what they are. What you really need is a Wideband O2, and you'd see what an excellent job this mod does of keeping the AF exactly where you want it (up top) where it really counts all the way to 7300 rpm.. Down low, just pulling the fuse once in a while does the job. That is all.... __________________ Broadway Auto Clinic..Home of Big Dicks Performance *Rick@broadwayautoclinic.com* 518-434-4077 http://www.BroadwayAutoClinic.com http://www.BigBoysFastToys.com 19T turbos from Blouch TurboDR Stage Three Heads Pauter connecting rodsWiseco Forged PistonsNew OE forged crank Nissan connecting rod bearings32X15X3.5 FMIC and 2.5" hardpipesTANABE SUPER MEDALION RACING HYPER exhaustcustom downpipeACPT 1 piece drive shaft RPS Stage Three Clutch Emange Blue and EO1 piggyback Koyo 2" aluminum radiatorDenso 660 injectors Greddy 60MM gauges in every flavorFJO widebandDawes Twin AF gageswater cooled oil cooler H&R lowering springs and ne OE struts5Ziggen 18X8.5 FN1OC Gunmetal wheelsGoodyear F1 tires**etc,etc

09-17-2003, 11:35 PM	#311 (permalink)
TurboBob Resident mad scientist Join Date: Jan 2003 Location: Near Detroit Drives: 86 GN 91 RT/TT Trader Rating: (17)	Umm, it depends..... On what, I really don't know (yet). You usually need to drive for 10-15 mins before the mid and high start to adjust. B

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09-23-2003, 04:27 PM	#313 (permalink)
wizard I drive, therefore I am. Join Date: Jun 2003 Location: Van Nuys, CA Drives: 92 Stealth TT Trader Rating: (1)	time 2 wake up this thread again: ok, my final conclusion on this setup: short version: does add some high end power, but low end gets worse b/c of tuning issues. long version: the turbos DO spool up quicker and hold more boost in 1st gear. I know this b/c my EBC started spiking like crazy (it couldn't compensate for the quick rush of air any more) (HKS EVC IV)... So it does add some more power in the higher RPMs range... but here's the problem: At normal driving speeds, this setup wrecks havock on the ECU trying to keep a stoich condition. With an ungutted MAS, equal amount of air goes through the middle of the MAS(to the sensors) as through the outside opening. However, with a gutted MAS, if you're at LOW throttle, air does not want to go through those damn honeycombs, and it just squeezes by through the openings w/out the honeycombs. But once you step on the pedal and the turbos start sucking in good amounts of air, then the difference in air movement becomes smaller because air gets FORCED into those honeycombs. Sooooo, lets say you normally drive at 25% throttle and that's what you tuned for... At 25% your A/F ratios are ok, but as soon as you press down on the pedal more, you'll see your O2 trims skyrocket (mine were around 160-165%). and if you drive at lower throttlw... say 18% then the trims drop like a rock (mine were at around 30-40%) this is b/c your MAS is not readind enough air (since air doesn't want to go through honeycombs)... So on average I was seeing my O2 trims going anywhere from 30% to 170%.... (with an ungutted MAS, Those numbers were around 80%-120%) THis means that the ECU has to compensate almost 3x as much for air flowing through the sensors all depending on how much air is being pulled by the turbos. THis is also a problem on my car for open/closed loop, the car hickups like crazy when it's entering/exiting loops. So in conclusion: It's a nice CHEAPPPP setup if you want quick power at the track, but in my opinion not worth it if you're like me and use your car as a daily driver b/c of the tuning issues. I ordered my MAF-T setup which should be coming in this week and I'll tell you how that does later.

09-24-2003, 08:57 AM	#318 (permalink)
wizard I drive, therefore I am. Join Date: Jun 2003 Location: Van Nuys, CA Drives: 92 Stealth TT Trader Rating: (1)	I was thinking about removing the center honeycomb, but then I read that EVERY single person that's done this had problems w/ it.... I guess its not quite true.... From what I understand, the purpose of the honeycombs is to take the turbulant air coming in and straighten it out for the sensors to read more accurately... So while I never did remove the center comb, I'm thinking it might give me even more problems in the long run than with the side combs removed only..... How do your trims look w/ the center removed/?? O btw, don't forget the screw at the bottom too, some people unscrewed it and got even MORE air going thoguth...... damn if somebody can set this up well, we'll have flowthroughs! You know what guys, you know how on the ARC2 87mm MAS, it has that little port going to the sensors..... I think if somebody could make a port like that for our MAF's and put it on a gutted one, We wouldn't have any problems with turbulant air, and still have plenty of room for the air to move, and probably not even have to tune idle to +15%...... umm...... I call royalties!

09-24-2003, 09:42 AM	#319 (permalink)
Gabe92RTTT U2SLOW Join Date: Aug 2002 Location: Albuquerque Drives: '92 Dodge Stealth TT Trader Rating: (37)	I would remove the center honeycomb and go out and take some logs of o2s and stuff, but the car is kind of appart now awaiting the fabrication of my DSM intercoolers. Once its running I will give it a shot. The only thing that I have found odd with my trims is the low plunges to 81 at idle, yet my o2s cycle ok. Once driving starts up, it picks back up to ~100. Mid is stuck at 110 and high is at 100. Drives fine, seems fine. Kinda ghetto to have to reset the ECU every now and then, but for my poor ass student budget, its ok for my weekend warrior.

09-24-2003, 02:09 PM	#320 (permalink)
Innovator Blowing hot air Join Date: Aug 2001 Location: Albany NY Trader Rating: (6)	I wouldn't worry about the actual valuse of the trims. If the car is at 14.7:1 at idle and cruise, all is well. If i's way off wack you will get a cel directing you which way to go with the fuel compansation. I can't measure trims on my 95, and the FJO is all I have, and it's been all I need to date. AF seems smooth and spikeless with all the combs removed. It doesn't really matter if the MAF measures the air accurately(because the combs are removed?), but what matters is consistancy. The AFC takes care of the accuracy aspect of it.