Removed Honey Combs - Advice Needed

[sp00ln]

Alright, so I'm running a 190lph fuel pump with 660cc's. After running some data-logs im running pretty rich, so I ordered an adjustable fuel pressure regulator. However, it is on some extreme backorder and it will not get here for awhile. In any event, to attempt to lean out my car a bit I removed the two side honey combs (2g) and backed the screw all the way out. The car seems like it pulls harder now and I'll attempt to tune it later tonight. I did a rough tune and it sputters at the higher RPMS (alot of fuel still) so I will lean it out a bit more. Through this I have brought down the timing to a more ideal range. I just dont want to see a high -% on the AFC. Could this lead to some potential problems with my car? Engine? What? Should I put the honey-combs back in and just be pacient and just wait for my AFPR?

Advice needed.

Thanks.

-Ryan

 

[Pizzy]

You're running a T-25 with 660 injectors?

Put the 450s back in till you get a bigger turbo and you'll be better off. The high -% is what you'll end up with as you're telling the ecu that there's less airflow and it will want to add less fuel. With 660's and a T-25, you want less fuel (hence the above 450cc comment). Pulling the honeycombs will help lean you out at WOT but it doesn't sound like the stock MAS is a restriction with your setup so there's really no need and only changing more factors making it a bigger headache to tune. High -%'s shouldn't hurt the car any as long as your EGT's are ok @ WOT. You have an EGT right? Datalogger too I hope? If not, definately don't risk anything and just put the 450s back in till you're really ready to go.

Although you shouldn't need an AFPR with a 190 pump, it's good tool, not just a means of getting to the stock level of fuel pressure. Once you get the AFPR (I'm still working on this method with my own car) adjust the fuel curve so that you are in the ballpark of 0% fuel trims on the logger. Then adjust the SAFC to fine tune each RPM. That's what I've been hearing at least...lemme know if that helps at all.

 

[Blk_99gst]

Removing honeycombs from the maf is just a terrible idea. Did you read somewhere that it was a good idea?

Pulling the honeycombs will help lean you out at WOT but it doesn't sound like the stock MAS is a restriction with your setup so there's really no need and only changing more factors making it a bigger headache to tune.

Amen to that Pizzy...

 

[Pizzy]

Removing honeycombs from the maf is just a terrible idea. Did you read somewhere that it was a good idea?

Most guys do it when they're so modded that the stock MAS is a restriction. They can either pull the side and lower honeycombs and back out the screw, or go with something like a GM MAF w/ translator.

Amen to that Pizzy...

haleluiah botha

 

[sp00ln]

I dont have a stock turbo, I was hoping that someone could just help me out based on my 31 degrees of timing while cruzing the streets and 21* while at idle. I just tried to make a broad adjustment by removing the honeycombs while I cannot get my AFPR.

I just want to hear if it's a good idea or not to do this mod in an attempt to make a broad adjustment to the air/fuel mixture.

The comment about a high -% numbers was because, yes, it does affect your car. Your ECU see's a certain amount of airflow (Hz) entering your car, and if you make it too negative it loads up your timing to compinsate. This is why I'm attempting to by-pass air that the ECU does not see so I can lower the AFC settings a bit. So, is this a good idea, or bad? Comments?

 

[Pizzy]

I'm not sure about the timing issue but I do know that my timing is fairly high at cruise as well. My car has 150K miles on it and still runs strong so it's probably ok.

If you can set the boost to near stock psi, 14-15 or so, I'd just put those 450s and honeycombs back in till the AFPR comes.

You have an EGT right? Datalogger too I hope?

I suppose you do have a logger if you know your timing numbers.

And I don't think the honeycombs out will have a perfectly linear effect on all your low and high settings. Your Hi settings will probably be much more affected by this which would make it even more difficult to tune. It's probably not a bad idea an I don't think you'll blow your car up or anything, but it a bad idea in that it seems like it'll only complicate things further than having 660s and no AFPR to move the fuel curve.

 

[kpt4321]

Why remove the honeycombs, when you can achieve the same effect with much more acuaracy and control with the SAFC?

 

[Pizzy]

Why remove the honeycombs, when you can achieve the same effect with much more acuaracy and control with the SAFC?

The comment about a high -% numbers was because, yes, it does affect your car. Your ECU see's a certain amount of airflow (Hz) entering your car, and if you make it too negative it loads up your timing to compinsate. This is why I'm attempting to by-pass air that the ECU does not see so I can lower the AFC settings a bit.

He's trying to avoid using high negative values on the SAFC to compensate for the rich condition by adding airflow through the honeycomb removal instead of taking fuel away with the SAFC.

 

[sp00ln]

He's trying to avoid using high negative values on the SAFC to compensate for the rich condition by adding airflow through the honeycomb removal instead of taking fuel away with the SAFC.

Thanks

 

[kpt4321]

He's trying to avoid using high negative values on the SAFC to compensate for the rich condition by adding airflow through the honeycomb removal instead of taking fuel away with the SAFC.

What?

If the ECU gives you 5% less fuel, it's seeing 5% less airflow. It doesn't matter one bit if it's seeing 5% less because the MAF is hacked, or 5% less because the SAFC is set to -5%.

I don't know what you are trying to say when you say "adding airflow through the honeycomb removal instead of taking fuel away with the SAFC." The reason that both of those things will lean the car out at WOT is because they allow the ECU to see less total airflow than what the motor is really taking in. From the ECU's point of view, they are the same thing.

Tune with the SAFC, not with the MAF.

 

[Pizzy]

I don't know what you are trying to say when you say "adding airflow through the honeycomb removal instead of taking fuel away with the SAFC."

What I mean is that by taking the honeycombs out you allow more air coming through the intake. Sorry if my words aren't technical enough but yes more air is coming into the engine with the honeycombs out.

If you lean out the car without adding airflow, then you're taking away fuel are you not?

Also, I'm just explaining what HE said.

 

[sp00ln]

Well, this is what Im *attempting* to do. Like you said, if the ECU see's 5% less airflow it will give me 5% less fuel, well, visa versa, if it see's 5% more airflow, it will give me 5% more fuel - this is what im trying to avoid. Im removing teh honeycombs so I can sneak in more air without the ECU compinsating for it in an attempt to make a broad adjustment to my air/fuel mixture because I am running super rich. After this adjustment, I tuned with the AFC to get a more precise flow. I'm in the -20s now on the AFC instead of the mid -30s. Im doing this because if I'm in the -30s the ecu "sees" more less airflow and loads up on the timing.

 

[Talonman]

what turbo? how about a set of 550s with your honeycombs reinstalled?

 

[kpt4321]

What I mean is that by taking the honeycombs out you allow more air coming through the intake. Sorry if my words aren't technical enough but yes more air is coming into the engine with the honeycombs out.

More air is coming into the engine with the honeycombs out? Is that so?

If boost is constant (which it is) and you drive in the same ambient conditions (constant charge temp) on the same engine, airflow remains the same. Simply removing the honeycombs doesn't let more air in, where is that air going to go? If you're all of a sudden flowing more air, the temp has to go down or the boost has to go up. That doesn't happen.

The only thing that removing the honeycombs will do is decrease the PR across the compressor wheel, which will eventually lead to slightly lower charge temps at full boost. However, the mass airflow difference that is a resultant of this is essentially too small to notice.

In addition, let's think about idle, before and after the honeycombs. Do you think that the airflow changes before and after you pull the honeycombs? Nope, if the airflow changed than the power produced at idle would change, and the idle speed would essentially go up. The airflow remains the same, but the airflow signal (Hz) seen at the ECU is decreased due to the fact that the MAF is no longer factory calibrated.

If you lean out the car without adding airflow, then you're taking away fuel are you not?

Where did I say that you weren't?

In either case, you are removing fuel due to a decrease in the correlation between true airflow and recognized airflow at the ECU. It's the same thing.

Also, I'm just explaining what HE said.

Don't you think he can do that for himself? Insisting that he was saying something which is wrong makes you just as wrong as he is; probably worse.

 

[kpt4321]

Well, this is what Im *attempting* to do. Like you said, if the ECU see's 5% less airflow it will give me 5% less fuel, well, visa versa, if it see's 5% more airflow, it will give me 5% more fuel - this is what im trying to avoid. Im removing teh honeycombs so I can sneak in more air without the ECU compinsating for it in an attempt to make a broad adjustment to my air/fuel mixture because I am running super rich.

Going negative on the SAFC does the EXACT SAME THING. It lets you add fuel airflow without the ECU compensating for it.

After this adjustment, I tuned with the AFC to get a more precise flow. I'm in the -20s now on the AFC instead of the mid -30s. Im doing this because if I'm in the -30s the ecu "sees" more less airflow and loads up on the timing.

If the ECU is currently seeing more airflow and giving you more timing advance than it was before you removed the honeycombs, then you are running richer then you were.

 

[Pizzy]

Insisting that he was saying something which is wrong makes you just as wrong as he is; probably worse.

No, it means I'm trying to explain what HE was saying, TO YOU. I didn't say a thing about if it was wrong or right. I said "this is what he said," and it was, so how am I wrong??

Stop being an ass.

 

[Blk_99gst]

After this adjustment, I tuned with the AFC to get a more precise flow. I'm in the -20s now on the AFC instead of the mid -30s. Im doing this because if I'm in the -30s the ecu "sees" more less airflow and loads up on the timing.

It's still not right; to take out honeycombs so that you are in the -20 with the safc instead of the -30's. Let me give you an example.

The maf measures airflow in hertz; we can agree on that. So let's say you have 1000hz of airflow coming in on an unhacked/stock maf. With no safc, then the ecu will see a 1000hz signal. Let's say you hack the maf/take 1/2 the honeycombs out. So now the ecu is seeing a 500hz signal and will deliver the amount of fuel associated with that, but in reality 1000hz of air is coming in. Back to the beginning, leave the maf stock, put a safc in there, lean it out so that the signal to the ecu is 500hz. The ecu will deliver fuel for 500hz, but in reality 1000hz of air is coming in.

The above situations are the same! The only difference is when you remove honey combs, then idle and normal crusing around town will both suffer. I would much rather have my safc set to the -30's and leave my maf in take, then to hack it so that my safc are only in the -20's.

So when you say at -30% that the ecu is seeing less air flow and is loading up on timing, that's wrong. It's the same scenario if you have the maf which could take away 10% of air, then only have the safc taking away -20%.

 

[Pizzy]

It's still not right; to take out honeycombs so that you are in the -20 with the safc instead of the -30's. Let me give you an example.

The maf measures airflow in hertz; we can agree on that. So let's say you have 1000hz of airflow coming in on an unhacked/stock maf. With no safc, then the ecu will see a 1000hz signal. Let's say you hack the maf/take 1/2 the honeycombs out. So now the ecu is seeing a 500hz signal and will deliver the amount of fuel associated with that, but in reality 1000hz of air is coming in. Back to the beginning, leave the maf stock, put a safc in there, lean it out so that the signal to the ecu is 500hz. The ecu will deliver fuel for 500hz, but in reality 1000hz of air is coming in.

The above situations are the same! The only difference is when you remove honey combs, then idle and normal crusing around town will both suffer. I would much rather have my safc set to the -30's and leave my maf in take, then to hack it so that my safc are only in the -20's.

So when you say at -30% that the ecu is seeing less air flow and is loading up on timing, that's wrong. It's the same scenario if you have the maf which could take away 10% of air, then only have the safc taking away -20%.

One thing that's a little confusing...
With the side and lower honeycombs out, wouldnt the ECU still see the same 1000hz of airflow since the passage that the sensor sits in is unaffected? I thought that by removing the honeycombs the ECU sees the same amount and the actual airflow increases because it is "sneaking" around the sensor, causing a lean condition.

Thanks for not biting my head off.

 

[Talonman]

since you have to add fuel for the air "sneaking around the sensor" you will be bumping the safc up, reporting MORE airflow to get more gas, and letting the ecu use fuel and timing maps closer to the actual wot condition that is really happening thus getting timing advance in the high teens low 20s where it should be, not in the high 20s (bad for head gasket).

 

[Ghost1984]

Even tho im not turbo, I took out the honeycomb and my car ran like complete ass, its not a very good idea so i wouldnt recommend doing it if your thinking about it

 

[sp00ln]

^^ I have an AFC so I can control how it idles! ^^

One thing that's a little confusing...
With the side and lower honeycombs out, wouldnt the ECU still see the same 1000hz of airflow since the passage that the sensor sits in is unaffected? I thought that by removing the honeycombs the ECU sees the same amount and the actual airflow increases because it is "sneaking" around the sensor, causing a lean condition.

Exactly. You're on the money.

since you have to add fuel for the air "sneaking around the sensor" you will be bumping the safc up, reporting MORE airflow to get more gas, and letting the ecu use fuel and timing maps closer to the actual wot condition that is really happening thus getting timing advance in the high teens low 20s where it should be, not in the high 20s (bad for head gasket).

That's is exactly what I'm trying to do. What I'm asking is if there's anything that I DONT know of that will get me into trouble?

 

[Pizzy]

since you have to add fuel for the air "sneaking around the sensor" you will be bumping the safc up, reporting MORE airflow to get more gas, and letting the ecu use fuel and timing maps closer to the actual wot condition that is really happening thus getting timing advance in the high teens low 20s where it should be, not in the high 20s (bad for head gasket).

I think that's what I said. Maybe we're agreeing, I'm not sure. :laugh:

 

[Talonman]

That's is exactly what I'm trying to do. What I'm asking is if there's anything that I DONT know of that will get me into trouble?

I guess if you log it , watch your 02s, and timing you should be able to do that if you can get your idle/part throttle to settle in. I would rather just run 550 injectors with all honeycombs in unless you have a bigger turbo and need the fuel. If you need the 660s you will need to get an eprom ecu, get a chip from dsmchips.com burned with your specific setup (2G MAS, honeycombs in or out, 660s) that will have adjusted fuel maps for your setup to run normal timing.

 

[sp00ln]

I guess if you log it , watch your 02s, and timing you should be able to do that if you can get your idle/part throttle to settle in. I would rather just run 550 injectors with all honeycombs in unless you have a bigger turbo and need the fuel. If you need the 660s you will need to get an eprom ecu, get a chip from dsmchips.com burned with your specific setup (2G MAS, honeycombs in or out, 660s) that will have adjusted fuel maps for your setup to run normal timing.

I dont have eprom I'm with ya on that one.

I basicly watch my o2's (tune for 94-96 wot) relative to the timing. My part-throttle runs perfect and every now-and-then I have some hickups with my idle. Other than that, the car's perfect.

 

[kpt4321]

since you have to add fuel for the air "sneaking around the sensor" you will be bumping the safc up, reporting MORE airflow to get more gas, and letting the ecu use fuel and timing maps closer to the actual wot condition that is really happening thus getting timing advance in the high teens low 20s where it should be, not in the high 20s (bad for head gasket).

Arrgh.

The reason you need to bump the correction up on the SAFC is because the MAF is showing you a LOWER airflow signal! The end result is the exact same airflow signal at the ECU!