Cap's MAF mod with fuel pressure

[Optimus prime]

Yep, ok, my figures are clearly pulled out of thin air then. Obviously peak power is going to be difficult to chase in N/A. From an engine performance perspective i'll crack on with the cheap mods I/M/E and general servicing. If I can get my hands on a cheap set of 2zz injectors i'll do the MAF mod and then turn my attention to the rest of the car for a few months such as suspension, bracing, poly's etc. I will later then revisit ECU (after hours of research) and then chase more power.

[lamcote]

The thing is, I reckon "just" getting 150+ flywheel hp would make a huge difference and that is realistic.
Then if you follow the weight loss advice as well you're onto a winner.
A Lamborghini engineer was interviewed the other day and he reckoned a customer would notice the effect of a 10kg weight reduction in a Huracan!

[Call the midlife!]

I'm screwed on the weight loss part, apart from the bits I've added to the car itself I probably carry 10-15kg of general shizz around all the time too!


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[Optimus prime]

Ok, I thought I would take the time to lay out what my plans are so you guys get a better idea of what I'm aiming to doing rather than just giving you sporadic information. Thank you all for your very informative posts so far and I really appreciate it coming from people who have actually been there or seriously plan on achieving their own goals.

I'm fairly handy with a spanner and I understand technical info fairly well. I'm lucky I have a mate with a proper garage so I'll be heading over there some weekends.

I've had the MR2 for about 4 weeks, in that time I have;

-   Replaced the radiator as it sprung a leak (obviously it's never been driven so hard  )
   I flushed the system twice and the coolant level is nailed on the max mark, it barely moves at all. And yes, the heaters work! 
-   Flushed engine oil and changed filter
-   Replaced spark plugs (I like to do that with new cars I own)
-   Changed the standard headlight bulbs as they were appallingly dim.

This weekend I plan on installing my BMC CDA intake with the original MAF housing (already cut out from another air box). I've ordered pipe work that will replace the standard airbox route but I will see if I can mount it behind the battery. As I'm using the standard MAF housing I think it's going to be too big to fit in that space.

Next weekend at the garage I plan on removing the pre-cats. I will also remove and wire brush the sub-frame, give it a spray of anti-rust primer followed by a few coats of hammerite.
Only after I've done the pre-cats I will install the MAF mod as there's speculation that the ECU over fuels at higher rev's to try and preserve the integrity of the pre-cats. No cats means no problems so I should be safe.

I then plan on buying Tein springs (and other recommended parts?) – I will follow this up with a 4 wheel alignment (I want to do this part after the sub-frame to ensure I get the best out of the alignment)

I will then move on to braded brake lines and maybe Green stuff pads but that depends on how much meat is left on the existing pads.

Although I fully appreciate losing weight in the easiest way to get it moving faster but I like all of the comforts – saying that the A/C needs a new rad but that can wait until next year now.

That's enough to keep me busy for a few months and I'll research into the ECU side of things.

What do you guys think, does that sound sensible?

[Call the midlife!]

Only comment I'd make there is start soaking your subframe fixings in Plusgas now, like this minute, unless you're confident they're all nice and corrosion free? Same goes for the manifold, three amigos  or you could find yourself taking all weekend to do the precats alone.
Probably don't expect to do the subframe in one weekend either if you hit stubborn nuts...


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[lamcote]

Sounds great to me. A detailed write up and spec for the intake installation would be great if you get chance?

[Optimus prime]

Sounds great to me. A detailed write up and spec for the intake installation would be great if you get chance?

I will certainly try and get this done. I will have to do it in two parts. one replacing the existing box and the other behind the battery at a later date! 

[shnazzle]

That sounds very sensible.

If I were you, stick to your original plan; make small tweaks to improve response. And your plans to make the handling best it can be are spot on.

You may (like me) find that the stock powered mr2 (with a few tweaks) is an absolute joy.
I'm on year 5 I think of stock mr2 power and I still drive it every day with a huge smile.

All of this mad power craving is starting to do my head in a bit.
Don't get me wrong, I love Helen's turbo MR2 (my wife), but it seems like nobody can just love the 2 for what it is anymore.

If I were you; get your intake sorted, maf mod, and maybe look at a bored out throttle body (MaxBore or Streetwerks). Then a good exhaust manifold and all the handling mods.
Enjoy it!
Look forward to the progress

[lamcote]

I'm screwed on the weight loss part, apart from the bits I've added to the car itself I probably carry 10-15kg of general shizz around all the time too!

Sounds like you could do with some carlonic irrigation!!

[Call the midlife!]

I'm screwed on the weight loss part, apart from the bits I've added to the car itself I probably carry 10-15kg of general shizz around all the time too!

Sounds like you could do with some carlonic irrigation!!

Hahahahaha! Nah, regardless of any plans for the future, mods wise, I'll not be doing any weight reducing. Other than the straight line speed, which would take drastic weight loss to improve anyway, the car is plenty quick enough for my current talent through the bends.


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[m1tch]

I'm screwed on the weight loss part, apart from the bits I've added to the car itself I probably carry 10-15kg of general shizz around all the time too!


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You can easily take off 10kg from the car as seen below for some of the weight I have removed when the car is in 'road trim', more if you remove the radio etc

ECU shield - 0.459kg - really quite pointless and rather heavy
Smaller exhaust manifold heat shield - 0.588kg - not needed if running a decat manifold
Larger exhaust manifold heat shield - 1.202kg - not needed if running a decat manifold
Front floor mats - 1.927kg - heavier than I expected!
Frunk lid - 1.218kg - easy to remove
Frunk plastic cover - 1.4kg - Few poppers to remove this item but means you can also check fluids easier
Engine vanity cover - 0.357kg - No real need for this
Sides of rear bin trims - 0.344kg - these are meant to pop out as standard to allow wider loads in bins (as per OEM instructions)
Rear bin door - passenger - 1.220kg
Rear bin door - driver - 1.205kg

Basic weight reduction - 9.8kg of basic unbolting/lift out items without loss of comfort/looks

If you have a breakdown recovery service also add:

Toolkit - 3.039kg
Spare wheel - 11.2kg
Frunk well - 3.418kg
Frunk under bracket (long) (2) - 0.278kg

Full road trim weight reduction - 27.7kg of weight removed before starting to unbolt trim or remove sound systems etc

[m1tch]

That sounds very sensible.

If I were you, stick to your original plan; make small tweaks to improve response. And your plans to make the handling best it can be are spot on.

You may (like me) find that the stock powered mr2 (with a few tweaks) is an absolute joy.
I'm on year 5 I think of stock mr2 power and I still drive it every day with a huge smile.

All of this mad power craving is starting to do my head in a bit.
Don't get me wrong, I love Helen's turbo MR2 (my wife), but it seems like nobody can just love the 2 for what it is anymore.

If I were you; get your intake sorted, maf mod, and maybe look at a bored out throttle body (MaxBore or Streetwerks). Then a good exhaust manifold and all the handling mods.
Enjoy it!
Look forward to the progress

I probably would have gone down this route if the engine didn't burn oil, if the stock engine made good power and was reliable in terms of the internals didn't need touching I would have kept the power as is - usually more fun to drive a low power car and use all the power than a higher power car on part throttle. I think my engine build is probably the most extreme of the 'whilst I am in there' fixes! Saying that I will be running my engine NA for the first year or so whilst I select all the turbo parts so it would mean I have a fairly close to stock NA engine but can rev to 8k.

[Call the midlife!]

I'm screwed on the weight loss part, apart from the bits I've added to the car itself I probably carry 10-15kg of general shizz around all the time too!


Sent from my iPhone using Tapatalk

You can easily take off 10kg from the car as seen below for some of the weight I have removed when the car is in 'road trim', more if you remove the radio etc

ECU shield - 0.459kg - really quite pointless and rather heavy
Smaller exhaust manifold heat shield - 0.588kg - not needed if running a decat manifold
Larger exhaust manifold heat shield - 1.202kg - not needed if running a decat manifold
Front floor mats - 1.927kg - heavier than I expected!
Frunk lid - 1.218kg - easy to remove
Frunk plastic cover - 1.4kg - Few poppers to remove this item but means you can also check fluids easier
Engine vanity cover - 0.357kg - No real need for this
Sides of rear bin trims - 0.344kg - these are meant to pop out as standard to allow wider loads in bins (as per OEM instructions)
Rear bin door - passenger - 1.220kg
Rear bin door - driver - 1.205kg

Basic weight reduction - 9.8kg of basic unbolting/lift out items without loss of comfort/looks

If you have a breakdown recovery service also add:

Toolkit - 3.039kg
Spare wheel - 11.2kg
Frunk well - 3.418kg
Frunk under bracket (long) (2) - 0.278kg

Full road trim weight reduction - 27.7kg of weight removed before starting to unbolt trim or remove sound systems etc

I know where you're coming from and understand your thought process but mine is a road car that gets driven spiritedly where feasible.
And some of the single track, back roads we've been down lately would be a nightmare to get recovered from for something as simple as lack of a spare tyre.
It's each to their own David, I admire your enthusiasm in pursuing your goals but a semi stripped out car with exposed framework etc just doesn't do it for me.


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[Optimus prime]

My plans have changed!

I personally don't like where I was heading with the BMC. I am sure I could get it looking right and the intake temps reasonable but I wasn't going to end up with what I wanted. So I've gone back to the stock air box for now and looking to sell the BMC to fund other parts of this project. I will later buy a cone filter and install behind the battery.

I'm working in the garage this weekend and will do the following:
   De-cat the pre-cats.
   Remove and spray the subframe.
   Do the MAF mod as I picked up a set of yellow injectors from Rutland MR2.

Wish me luck, i'll tell you how it went.

Oh, before I forget, what have people used as a riser for the MAF. I'm thinking a 5.5mm spacer with some 1mm to 'fine tune' the setup.

[lamcote]

It's a long time since I looked at this mod but I think the official spacer had a notch in it to clear an obstruction. A simple spacer might need some work to fit and seal properly, but not sure.

6.35mm was what Cap recommended as ideal.

https://www.google.co.uk/search?q=maf+mod+riser+picture&client=tablet-android-pega&tbm=isch&tbs=rimg:CX1TRyzP1hDGIqAB_1ruNp-qv0d2C51vdPGiLqg7CS-1SXyp3xCITBil9CgBYt47tOYFp5VmPLktLa_1YEdyX9Qe0CGL4fvSTpReGNK3GxjGzCJuRwl46xlsyHUPA2SXHZ7atEsphMgOwvIaOQugq1fguPTl-n4-Js7yZGI-LnJxVrSqF_1gpRYho2TXAiCvPupZK9Vs7fA-FKo0ZVCq4gb5AfpkM1xQNXbSwdmdioSCf67jafqr9HdEY9N8xTcDLlXKhIJgudb3Txoi6oRj03zFNwMuVcqEgkOwkvtUl8qdxEyex_1TkhOJiioSCcQiEwYpfQoAEU8noSCgDopfKhIJWLeO7TmBaeUR4FQWQQPezl8qEglZjy5LS2v2BBGZ5W0rJjXTfioSCXcl_1UHtAhi-EZC8b19zfkRmKhIJH70k6UXhjSsRsX6L7RigUZQqEglxsYxswibkcBHEucbT4CuV8yoSCZeOsZbMh1DwESwp3V0SbEHyKhIJNklx2e2rRLIReKuknEgt1J4qEgmYTIDsLyGjkBHvqJQ2ysRtIyoSCboKtX4Lj05fEY9N8xTcDLlXKhIJp-PibO8mRiMR8FC3zmwMmagqEgni5ycVa0qhfxE82iSkmAUBpSoSCYKUWIaNk1wIEWPih2LGaHYLKhIJgrz7qWSvVbMRb0K942malPsqEgm3wPhSqNGVQhEmOvoyuzy8ICoSCauIG-QH6ZDNEWj9fEh5ekpMKhIJcUDV20sHZnYRJ8P96XKBTA8%3D&tbo=u&ved=2ahUKEwi9waKi3e_cAhXHAcAKHUj9BMoQuIIBegQIARAy#imgdii=jCDrNF0Y-mvBZM:&imgrc=WLeO7TmBaeWHPM:

[Beachbum957]

It's a long time since I looked at this mod but I think the official spacer had a notch in it to clear an obstruction. A simple spacer might need some work to fit and seal properly, but not sure.

6.35mm was what Cap recommended as ideal.

The "good" spacer does have a small notch, but many have made spacers from plastic pipe, etc and made them work.  The MAF mod is very popular in the US, but it only works properly with the stock airbox, and it mainly just improves the midrange.  I have been running it for years, and it does what it is intended to do, which is to "fatten" the midrange in the 3,000 - 4,500 rpm range and pull a bit smoother in that range, particularly at part throttle.  It also gives slightly better fuel economy.  But as for top HP, a couple have done dyno tests before and after, and the difference at full throttle isn't much.  The most reported was a couple HP.  Still, it is a cheap modification that does work

[Optimus prime]

I don't think I'm going to get much luck in finding official spacers, I'm going to have to go at it alone. I have been thinking that 30mm plastic piping will do the job, I need to have a play. I have the injectors so that's the 'hard part' out of the way

I will go with the official spacing requirements (1/4") on the stock box and later play with an induction kit located behind the battery.

[lamcote]

It would be great if you would provide details about how you get on?

[Optimus prime]

I will keep you guys updated as this mod, although well documented has dried up and finding a UK solution for the spacer is difficult to come by.

[shnazzle]

I will keep you guys updated as this mod, although well documented has dried up and finding a UK solution for the spacer is difficult to come by.

I'm not sure if I've asked before but maybe Steve (widermuller) can mill us some.
If we can get an existing one to him. @Dev?

[Optimus prime]

finding the profile of the original is a task... As for the height i'm seeing conflicting opinions/suggestions. 1/4 inch or 5.5mm, that's why i'm thinking about using a 5.5mm spacer and then using washers to fine tune it

[Optimus prime]

Ive found someone who will be able to machine a plastic spacer. Question is, how high should I make it? I will get a couple done so i'm happy to try a range of heights.

[lamcote]

I'm sure I saw 6.35mm quoted mainly, however there seems to be some tunability based on the following quote from Cap about the installation:

"1) Install the Yellow Injectors
2) Install the Spacer
3) Check for Drivability..  and Look at Fuel Trims..

The 'Bench Mark' I used was a Long Term Fuel Trim of about -7..  it will range from about -5 to about -10..  If you are More Negative than -10 then you will need to raise the MAF..  if you are More Positive than -5 you will need to Lower the MAF..

All the MAF Mod does, is fool the ECU into thinking the engine is LESS loaded than it is..  so it will give MORE ignition advance..  The Side effect of this is the ECU will also give LESS Fuel..  So the two choices are Raise the Fuel Pressure or install bigger injectors..  I chose the Injectors as it simpler to do..  but either will work.. 


The Yellow Injectors were my first stopping point..  I set the MAF height to give a MID 12's AFR at WOT..  my STOCK set up was running in the 11's!..  My Next step was to go to the 'Brown' Injectors and Trim MAF Height to give 12's AFR at WOT and check drivability..  That never happened..
My 1ZZ is now Sporting a Crower Stage 1 Cam..  so any work I do will not be reflective of a Stock Machine.. The MAF Mod and the Stock ECU are playing nicely with the Stage One Cams..  The car scoots nicely now..  So I've stopped tweeking on it.. Also I've moved over to a 90's 300 ZX NA as my Daily Driver..  so the Spyder is not getting the miles it was..

With my STOCK engine I was getting Heat Soak Problems on +100F days on LONG drives pulling hills..  that is why I recommend bumping up the RON number..  California has 87RON!..  and I had to go to 91 to stop the Heat soak issues.. (91 is all we can get in the Peoples Republik of Kalifornia ) So I just run the 91 all the time as an insurance policy..  Winter I'll run 87 if it's not expected to get hot..

Learn what Engine Pre-Ignition/Knock sounds like..  If you hear it you have tuned it improperly.. 

I like to start out with Lo Octane fuel..  as I will hear the knock and it will let me know where on the Engine Load it happening..  then I can always Bump Up in Fuel to cover it..  "

[Optimus prime]

cheers lamcote for this, I have read it before and found it very interesting.

What I make from my research is as follows:

Caps, -7 LTFT benchmark means the yellow 310cc injectors are over fuelling by default but the ECU is correcting this to reach stoichiometry. This is based on a 6.35mm spacer and removed vanes:

Raising the MAF reads more airflow and adds more fuel; thus retards ignition timing (using the suggested spacer profile) – (If you are More Negative than -10 then you will need to raise the MAF) – in this scenario the ECU in closed loop is reading too much fuel in the mixture, hence the LTFT of -10 or less

Lowering the MAF reads less airflow and adds less fuel; thus advances ignition timing (using the suggested spacer profile) - (if you are More Positive than -5 you will need to Lower the MAF) - in this scenario the ECU in closed loop is reading too less fuel in the mixture, hence the LTFT of -5 or more.

Only in open loop is the ECU referencing to its MAP's based on the input received from the MAF. And applies advanced timing and reducing fuelling by default. The lack of fuelling is adjusted by the huger capacity yellow injectors. But again in closed loop, the ECU has corrected for the richer condition as seen by the LTFT.

If I have the above working correct, then the potential danger zone of detonation is having the MAF too low as the timing is advanced and the AFR is running lean?
On another note, how do you read AFR? I can only access fuel trims.

[lamcote]

You are the wrong way round with the raising and lowering.

Raising the MAF reads LESS airflow (and advances the timing) and lowering the MAF back down towards its normal position reads relatively more airflow until it gets back to normal. When you refer to lowering the MAF you are never actually lowering the MAF in real terms ie below its standard position, you're just not raising it as much. This means that, as long as you have fitted the yellow injectors there shouldn't be a detonation danger zone (unless you raise it way beyond the recommended 6.35mm when it might go all wrong) because you should only be running rich.

You need a wideband O2 sensor to read AFRs but you shouldn't need to do this if you are staying within Cap's suggested parameters. You just need the LTFTs. If the LTFT is less than  +/- 10% (and STFT is close to 0) you know the ECU is happy with the resulting AFRs so you should be too. But you will need to run it long enough for the STFT to fall back to close to zero before you are happy of course.

Although we're not sure how it all works, we believe the closed loop LTFT is used by the ECU to modify the open loop maps so it all seems to work nicely in both closed and open loop.