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Lowering the maf voltage at a constant airflow results in a decreased load calculation. So it advances the timing and leans the fuel. Both good sounding as the 1zz ecu runs too rich at wfo. The possible bad thing it also does is change the vvti target.

Cap on a side note. I found a smt ecu that allows a higher rev limit. The one thing the 2zz smt car couldn't overcome. :)
 

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thanks LR, so to sumarize in my own words:

so modifying the intake (either making it larger, or moving the maf up) causes more air to enter the engine than is being measure by the maf?

this in turn makes the ecu think there is less load on the motor, and this increases ignition advance?

and finally the larger injectors or increased fuel pressure is required to add fuel back in, b/c more air is entering the system than is being measured

I like where this is going
 

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keep up the good work cap,

this may have a real good application in STR. I don't understand why when you were able to change wot afr from 11.5-13 it did not have any affect on performance?

If this is the case, I don't understand what installing the 2zz injectors acomplished, or similarly what the fuel pressure modification would acomplish if changing the afr from 11.5-13 did not have much influence on performance

i guess the key must be changing timing? what is happening in the load tables?

I am a bit lost, could someone please explain

thanks
Lost regarding?

As a general statement, timing advance has a much higher percentage impact on overall torque produced than running a leaner burn. You typically want to run as lean as your motor will allow you, within the safety zone of the octane you are running, then advance timing until you reach peak torque, then back it down a tad for some safety margin.

It is a myth that leaning out your motor produces much more power, if thats what you were questioning.

When adding forced induction, you need to retard the timing and richen up the mixture to compensate for the increased pressures and temperatures in the combustion chamber. This is a key that most people dont get and think they just "make the AFRs correct" after they strap on a SC or Turbo. Timing is the key to torque production. All the rest is pretty much just letting you advance timing.

Hope that helps.
 

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cap,

when you added your 0.25" maf spacer and were achieving the fuel trim of -6, did you have the stock vanes in place?
 

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Discussion Starter #85 (Edited)
I'd Prefer to Mod the Injectors.. they are Easier to get to..

But with the Fuel Pressure Mod, I can Increase the Ignition Timing, by Running a Larger MAF Housing ( or spacing the MAF up ), and then fix the Lean caused by that Larger MAF Housing..

Apex17..

I did not get siginifant improvement in Performance, because the Difference in 'Burn' is not that great between 11 or 13 if the Ignition is too late..

By Increasing the MAF Housing.. we are reducing the Velocity of the Intake Gasses.. and the ECU does it's Load Calculations on Velocity by way of the MAF Sig.. then ECU thinks the Engine is not working as hard, and will give it more Ignition Advance. ( We are fooling the ECU ).. but the Draw back to this is the ECU will also reduce the Injector Pulses... So less Fuel..

Now this is where it get 'Complicated'.. The ECU will sense the Lean Mixture in Closed Loop, and Fix that by Adding Fuel.. ( + on the Fuel Trims ).. BUT when the Fuel Trims get past about 10, the 'Rate' of fuel Enrichment will not carry over into the Open Loop Wide Open Throttle Territory.. and the Fuel Mixture will get Lean at WOT..

So to fix that, either ADD injector Size so the Fuel Trim is Less than 10.. Or Add Fuel Pressure.. Same thing..

If the Fuel Trim stays ABOUT + or - 5, then the WOT will be ABOUT right.. There is a Compromise.. the ECU will naturally add too much fuel at WOT, so you really want the Fuel Trim to be -5 to 0..

It's all a Balance.. And with the Cute Trick of adding the Spacer Below the MAF.. I can Taylor the MAF sig to give me any ignition advance I want.. then by adjusting the Fuel pressure, I can fix the WOT fuel Mixture..

Cap
 

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Discussion Starter #86
cap,

when you added your 0.25" maf spacer and were achieving the fuel trim of -6, did you have the stock vanes in place?
No.. I took them out..

Need me to make you one?.. Can of Spray paint will make the Yellow Injectors Green!..

Cap
 

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Discussion Starter #87

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I did the last 2zz smt swap with a 65mm dbw 2zz t/b. The car that is (still) kicking my ass is a 1zz smt turbo running a pfc.

I put a 6 puck act xtss monster in it today. She's holding the turbo's power now but lurches badly at take off. It has gotten better driving it but I don't think it will learn it's way out of it. I will finish the tuning tomorrow and give it a chance to learn over a few drive cycles. I will also do a fresh couple clutch learn if it doesn't improve. I think the partial engage point it seeks is too close to the clamp point. I will be pulling it back out tomorrow and putting a full face disk in with the monster pressure plate if it doesn't make itself happy.

The rev limit test was today when I was finally able to add some timing to the turbo car. I set it at the stock 6850 due to the last smt raised rev limit fail. Went to 7100 today without issue. Straight pull all the way to redline with no clutch hiccup. I see me selling a couple spyders and buying and 05 phantom grey/blood red interior smt soon. Built/supercharged/2zz/smt sounds gooood. :)
 

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so per the street touring rules, can't do injectors but can do fuel pressure regulator

I was hoping to somehow be able to install a fuel pressure regulator like this:

http://www.summitracing.com/parts/RPU-5030/ or

http://www.monkeywrenchracing.com/product_info.php?cPath=28_174&products_id=273

and be able to vary the pressure as a way of varying fueling

however looked at the location of the fuel pressure regulator and was disapointed that it was located inside the fuel tank, basically part of the fuel pump, so I don't think the above regulators will be able to work

if I do pursue this as an avenue, will an LM-2 reading from a wideband and pulling OBD-II data about timing be sufficient to "tune" my engine?
 

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Discussion Starter #91
Well, I just tried my hand at Bumping up the Stock Pressure Regulator, using Curts Method.. Mine ( Spare ) is now 60 psi.. that would be the Same as running 400 CC Injectors on Stock Fuel Pressure..

So if you get that First Regulator mounted in line.. and Use the Fuel Pressure Regulator I just Screwed up to 60 PSI.. You'd be able to get the 52 to 54 PSI Adjustable necessary..

How are you going to Hook that regulator to the Fuel Rail?..

Cap
 

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i don't know how I would get the fuel pressure regulator in line, just thinking out loud

why is 52-54 psi the magic number?

is fuel pressure increase proportional to increase injector pulsewidth?
 

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Discussion Starter #93
Injectors are rated at 'Some' fuel pressure.. The Green 1ZZ's are 280's.. I'm running yellow 310's.. or 1.107 bigger.. so if I was running 44 PSI before and went to 310 CC Injectors to 'Fix' my Fueling.. I could do the Same thing by raising the Fuel Pressure By 1.107.. or 49 PSI.. if I went to the Brown 330 Injectors.. Id be about the same as 52 PSI.. this will be my next step when I raise the MAF 1/2 Inch..

Cap
 

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Discussion Starter #95
I like the Fuel Pressure Requlator you found.. I'll get one and see how to mount it..


This PDF is if only tuning by Fuel Pressure.. I'm not.. that is the Final Step..

I'm tuning by Adding Ignition Advance by Lifting the MAF.. then Fixing the Lean, by adding fuel Pressure..

So you would need to Ignore the Driveability Issue Reference.. and Only Focus on the WOT stuff..

So.... When are you going to add your Wide Band?.. you cant do much without it..

Cap
 

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Sounds interesting. I have a wideband and will help you apex.
 

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well I had no idea about any of this until I read this post yesterday (had to read it 3 times, b/c I know very little about engine management)

realistically this project will have to be put on hold for me until the fall, I'm busy with the scca solo season this summer (2 weekends a month autox'ing, still trying to dial in my suspension)

once the main season ends, this fall I'll need to:

- swap out precats (yes I run with precats :eek:) to a gutted header so I can get real afr readings
- install crimped fpr so I can get fuel pressure above stock (since this is getting into the gas tank, I might as well install my harddog rollbar thats been sitting in the closet)
- if possible install variable fuel pressure regulator
- learn how to log data afr, and timing, knock

LR this fall if you are interested in playing with a basically 100% stock engine spyder (except catback) - you are more than welcome to mine

Cap, if you'd like to postpone sending the little spacer - that's fine.

Just to keep you guys up to date, the SCCA has a proposal to allow common piggybacks(like emanage) next year. We won't know the outcome until Jan 2012, but even if piggybacks are allowed and this solution can get 80% of the benfit for 20% of the cost for header/catback mr2, that would be an awesome solution, and I know what I would choose.
 

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Bumping this up because it is one of the best threads on 1zz performance and discusses a rarely talked about topic of the 1zz ECU.

Also, I recently purchased a Weapon R intake as it seems to be the most recommended intake on spyderchat. I measured the distance for the tube entrance and exit of the tube where the MAF is placed. The tube is 2.25" vertically and horizontally on both ends with the MAF placed in the center. From the top of where the MAF mounts to the bottom of the inner part of the tube is 2.5". There are no vanes of any kind except inside the air filter itself maybe, I'll let the pics do the talking:

*Preface: I think there are two versions of the Weapon R intake for the spyder with the only change being the filter. You can tell the difference between my filter and Andres' Weapon R. I think I bought the crappier one =(

Andres' Weapon R:
http://spyderchat.com/forums/showthread.php?40481-My-STR-set-up...&p=713695&viewfull=1#post713695

Hmm, dang Weapon R only shows 1 intake listed for the mr2 spyder =(
http://www.weapon-r.com/index.php?act=view_product&id=435

On the sheet that came with my intake it lists two part #s, Hyper Intake: 905-122, and Dragon Intake 805-122

I think I have the Hyper Intake and Andres has the Dragon Intake...

However, I believe the tube is the same so the rest applies. If someone would like to measure their Weapon R intake tube to confirm, I'd be much obliged.

Pictures:
Looking inside the filter...Are these vanes? not sure...guess it doesn't matter since I have the wrong filter.


Full intake assembled with how I believe it goes on the car if your looking into the engine bay


Entrance:


Exit:


Pipe where MAF is placed alone:


The bottom most part of the MAF is half an inch from the bottom of the tube. I found this difficult to measure but I feel pretty confidant about it. I should of measured the length of the entire MAF assembly then subtract that from 2.5” which is the distance from the top of the MAF mounting into the tube. Also, not sure how the curve of the tube affects the MAF.

MAF placed inside Weapon R this is looking into the inlet


MAF placed inside tube looking at outlet


Stock airbox opened up:

Notice the wall on the left side, I found that interesting and was wondering what purpose it serves.

The Weapon R tube is smaller than stock (2.25 ID vs 2.56 ID of stock) but since it doesn't have any vanes I'm guessing it acts like a bigger tube effectively and becomes very similar to stock. This is probably why people don't report problems with the weapon R as opposed to a 2.5" ID no vane intake.

I don’t particularly like the Weapon R intake because it is a smaller ID tube than stock (2.25" ID vs 2.56" ID stock) and it doesn’t have a real velocity stack (It looks like the better filter version does). I'm guessing it acts like a bigger tube effectively and becomes very similar to stock. This is probably why people don't report problems with the weapon R as opposed to a 2.5" ID no vane intake.

My idea was to cut out the stock maf tube and use a 3” coupler to add my 3”->6”” velocity stack than my 6” K&N Filter I have laying around. Very similar to what this guy did:

http://www.lotustalk.com/forums/f154/another-diy-intake-about-66-a-27694/

Except with a velocity stack and a heat shield to separate the intake from the engine bay heat. I have a OBD-II scanner/logger coming soon so I will log my stock intake fuel trims/IATs than try my DIY intake and maybe this Weapon R and report back.

Any thoughts on my plan?
 

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Discussion Starter #99
I do hope you realize that it not about the 'Intake'.. ( AGM/Wepon R/ Etc ) it's about the Dimentions of the Intake, and how that relates to the MAF Sig.. As seen Here ...



The Filter is only Bling..

All's you are doing is Increasing the Intake to get more Ignition advance, ( NOT more Air ) and Making the Fuel Mixture Leaner is a Side Effect.. so SOMEWHERE you have to fix the Mixture..

How are you going to Fix the Lean Mixture that you will be creating?..

Cap
 

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My thinking was by using the stock maf tube I wouldn't be lean but I guess your saying the air filter doesn't matter. I was hoping to relocate to the side vent to help reduce heat soak and cool down IATs once moving since this is for autocross.

I also thought the stock ecu ran pretty rich so even if it leaned out a little via ignition advance that would be ok but I guess not.

I have a Emanage Ult and a harness to plug it in but don't have a bung for a wideband. Need to fab up a downpipe with a bung because the TPD downpipe doesn't fit apparently :(. But once thats installed the intake doesn't matter since I can adjust timing/fuel at my own will and throw a 2.5" no vanes intake on it if I want to relocate to the side vent.
 
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