Mp3 ecu swap questions

Has anyone with an MP3 ecu or a reflashed ecu tried to run the car on regular unleaded fuel?

Mine was run for years with 87 with no issue. There is a noticeable difference in power although minimal. About 4 mpg difference too. Can't compare the difference with regular p5 ecu though.
 
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I haven't installed yet to be able to tell. My car is in storage till March April just turning wrenches on it for my winter project. I'm going to run 91 octane because it's roughly 1.18$ a litre
 
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There is no reason to have any issues with passing emmissions doing the ecu swap & removing VTCS.
 
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As if they would know about it anyway? Mp3 ecu won't read from it so the butterfly's should be removed
 
I'm certain when I posted "remove VTCS from intake" that that = butterfly's being removed. Cleaned up previous post so you can just focus on the last sentence that was there before...............maybe there's an argument for that statement?
 
Just ordered my MP3 ECU reflash from Spicy. Will install hopefully by the end of the week.
 
Just ordered my MP3 ECU reflash from Spicy. Will install hopefully by the end of the week.

Congrats, man. you'll love it. No joke on that kick panel cover though, its sharp as hell...so take your time haha. I read at least 5 posts of different guys cutting themselves, figured knowing about it...i'd be fine...nope...
 
The panel is like a razorblade.
I cut myself to the bone and didnt even feel it.

Wear GLOVES.

I ended up putting 1/4 Split Loam around the edge with RTV Silicon to hold it on.
 
The panel is like a razorblade.
I cut myself to the bone and didnt even feel it.

Wear GLOVES.

I ended up putting 1/4 Split Loam around the edge with RTV Silicon to hold it on.

haha yeah, i have a nice scar on my palm now...and just like you, i didn't even know about it until my hand felt wet and i wiped it on my jeans...

at least now i can tell people i disabled a swordsman with my bare hand...
 
Now because the tune disables VTCS, will that lower the life of the cats since they are not being warmed up the same on start up? Are their any issues that come along with not using VTCS?
 
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You could ask all the MP3 Owners..

You would be basically making your car into a Stock MP3. I don't understand why you are thinking about modifying the car if you are worried about something as simple as changing a catalytic converter in a couple of years.
 
Now because the tune disables VTCS, will that lower the life of the cats since they are not being warmed up the same on start up? Are their any issues that come along with not using VTCS?

Not really, no...although i didn't buy an MP3 or anything, but i don't think thats exactly what VTCS does anyway...

VTCS is basically an elaborate 'choke'...it uses butterflies to restrict air flow and cause turbulence right at the intake section of the head...which does two things, both giving the same result...

The restricted air flow automatically richens the mixture WITHOUT adding more fuel, the holy grail of cold start emissions...you get a nice rich mixture that burns very slowly and evenly heats up the combustion chambers...but unlike the standard protocol for this (dumping in fuel), the computer can use the same fuel mapping as if the engine was fully heated already...

the other effect is the turbulence the system creates...It spins and throws the air around, which allows it to mix more thoroughly with the gasoline being injected...it also helps reduce gasoline condensation on the ice cold cylinder walls...both of these bring the 3rd gen protege into U-LEV compliance...and thats about it...

The difference with the Mp3 ecu is that it doesn't have a protocol for cold starts that utilizes VTCS...it richens the mixture the old fashioned way (dumps in more fuel)...if anything, this will actually heat up the pre-cat faster than the VTCS system will...as more air is getting into the chambers, and more gasoline is being injected...so the overall intake charge is larger, and will heat everything up faster...although, its marginal...and not really noticeable to the driver...

so realistically...there will be no difference to pre-cat life...and actually, how quickly the cat is warmed up will have no real effect on its life cycle...cat temp only effects its ability to 'eat' unburned hydrocarbons...not really how long it lasts...

The only real issue between these ecu's and VTCS is when you remove or disable the system and still use a standard ecu...of which is looking for the VTCS, and providing fuel requirements as if the system works...if you do that, you most definitely WILL have some cold start trouble when the temps are very low...the mixture will be overly lean, and there will be noticeable hesitation at below freezing temps...after it finally warms up, everything will be normal...but its hard to say that setup is ideal for people that live in colder climates...
 
^^thanks man, and you're quite welcome...

One other thing, don't confuse VTCS with VICS...Very different systems, but both are in the intake manifold...VICS is still used with an MP3 ecu, and its a system to change intake volume at different operating ranges...low rpm the system is closed, reducing the intake to long and narrow single runners...at higher rpm the system is opened, which basically doubles the runner size...

you'll often see in build threads where someone removes VICS...but be careful about that...That is a mod that should only be considered for turbocharged engines...where a turbo is forcing air in anyway, so you realistically never need a small and restricted runner setup...if you yank it from a NA 2.0L engine...you'll immediately lose low end torque and response, as you just made VICS 'always on'...which doesn't net any top end results anyway...the system did that before...

Lastly though, back to VTCS...if you did purchase an MP3 ecu...there is literally no reason to keep VTCS in your intake manifold, unless you ever plan on returning to the stock ecu...emissions checks and visually inspectors will never know its not intact...and the VTCS system when off...rides straight across the end of the manifold...even with the butterflies 'flat', its still blocking intake charge to some degree...
 
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Not really, no...although i didn't buy an MP3 or anything, but i don't think thats exactly what VTCS does anyway...

VTCS is basically an elaborate 'choke'...it uses butterflies to restrict air flow and cause turbulence right at the intake section of the head...which does two things, both giving the same result...

The restricted air flow automatically richens the mixture WITHOUT adding more fuel, the holy grail of cold start emissions...you get a nice rich mixture that burns very slowly and evenly heats up the combustion chambers...but unlike the standard protocol for this (dumping in fuel), the computer can use the same fuel mapping as if the engine was fully heated already...

the other effect is the turbulence the system creates...It spins and throws the air around, which allows it to mix more thoroughly with the gasoline being injected...it also helps reduce gasoline condensation on the ice cold cylinder walls...both of these bring the 3rd gen protege into U-LEV compliance...and thats about it...

The difference with the Mp3 ecu is that it doesn't have a protocol for cold starts that utilizes VTCS...it richens the mixture the old fashioned way (dumps in more fuel)...if anything, this will actually heat up the pre-cat faster than the VTCS system will...as more air is getting into the chambers, and more gasoline is being injected...so the overall intake charge is larger, and will heat everything up faster...although, its marginal...and not really noticeable to the driver...

so realistically...there will be no difference to pre-cat life...and actually, how quickly the cat is warmed up will have no real effect on its life cycle...cat temp only effects its ability to 'eat' unburned hydrocarbons...not really how long it lasts...

The only real issue between these ecu's and VTCS is when you remove or disable the system and still use a standard ecu...of which is looking for the VTCS, and providing fuel requirements as if the system works...if you do that, you most definitely WILL have some cold start trouble when the temps are very low...the mixture will be overly lean, and there will be noticeable hesitation at below freezing temps...after it finally warms up, everything will be normal...but its hard to say that setup is ideal for people that live in colder climates...

Learned quite a lot from that, thanks for the write up! Am I correct to assume the car would use more gas since it is using more fuel to create the rich mixture with the MP3 ECU? Is it's effect enough to be noticed in day to day mpg?
 
Negligible. You will not notice the difference unless you idle your car for hours.

You are more likely to kill the MPG, by continually accelerating harder to see if the ECU is making a performance difference.
 
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Learned quite a lot from that, thanks for the write up! Am I correct to assume the car would use more gas since it is using more fuel to create the rich mixture with the MP3 ECU? Is it's effect enough to be noticed in day to day mpg?

If I baby mine I get 32 mpg, normally I get 28-30 though granted the 17s and 100 lbs of subs and box don't help any along with a poorly maintained motor. It's only gona be more rich on cold starts, the mp3 ecu actually leans it out a little bit iirc,
 
Luken, as they said...not really...idle uses such a small amount of fuel it really makes no difference to what you you'll notice...

the only thing that made the government love VTCS and give the car a U-LEV status is that each car uses a few ounces less fuel at cold start idle over a few months...multiplied by thousands of cars...

Its simply a marginally amount 'cleaner' during a cold start for a few minutes...multiplied by thousands of cars over several years...that definitely adds up, and why its an emissions based design...but a single user removing it; you'll never know...and the mp3 ecu, having far superior open loop maps...will give you an extra few mpg over the stock ecu...so overall, you'll actually use less gas...

like Tweety, I easily get 32 to 33mpg driving to work with an MP3 ecu...mostly 60mph or so on highway'ish roads...I'd regularly get 30 or 31 (only ever got 32 for a tank with extreme attention) with the older ecu, and i do notice it takes less throttle input for climbing hills or passing in 5th with the new computer...thats probably where the better mileage is coming from.
 
You can pass in 5th? Even on interstate I have to down shift to 4th although mine is 100% stock other than Sri which doesn't really count
 
yeah man. I can get to work about 30 miles away, up and over a couple of decent grades...and never leave 5th...and its all 55mph limited roads, so i'm even lower in the band than on a highway...Now passing in a hurry up hill at 55mph at 2700rpm or whatever it is, that doesn't really work in 5th...

I guess its the mods...to be honest i only drove a completely stock p5 for a month or two before i started doing stuff...not that it ever got crazy, but enough usable power to leave it in 5th for all but the steepest hills...
 
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