Stock ECU capability, low boost?

[MrT]

Hello all
Toying with the idea of very low boost on a stock ECU but not finding much info about its capability. Seems since everyone wants to remap, a chip or stand alone is fitted by default. Does anybody have experience/info on the stock ECU and ideally fuelling tables etc and what added induction the ECU might handle. I don't want power, just driveability and improved volumetric efficiency, plus a bit of fun.
Any constructive input/experience towards being able to do it appreciated. Anything else, this is not a chat thread, please keep opinions out and only add experience/data to the discussion.
Thank you

[m1tch]

I think most people want to remap or change out ECUs as its the safer option, saying that the PFC uses the MAF for airflow so it would be using airflow for the fueling tables - more air into the engine via a turbo would mean it would use a different part of the fueling map.

Just having a quick look some MX5 threads it seems they sometimes get away with the stock ECU on low boost by using a vacuum/boost referenced FPR - you could also run the stock injectors at a slightly higher base pressure for additional flow to keep everything a bit richer. I am not sure how the stock ECU would adjust the fueling as it would try and adjust the fuel trims to run slightly leaner than you would want - perhaps unplugging the stock O2 sensors would stop this and you would then run a wideband O2 gauge.

I don't think the stock MAF will be maxxed out but its more about the stock fueling tables - without being able to see where in the tables the ECU is taking fueling and timing from it would be difficult to see how close to max the tables are.

[Essex2Visuvesi]

The power enterprise turbo setup runs on the stock ECU with some minor mods to the fuel pressure regulation and knock sensor.  I think a lot of people who used the PE kit went for some kind of piggy back ecu long term.
When I get home I'll PM you the info I have gathered.

[m1tch]

The power enterprise turbo setup runs on the stock ECU with some minor mods to the fuel pressure regulation and knock sensor.  I think a lot of people who used the PE kit went for some kind of piggy back ecu long term.
When I get home I'll PM you the info I have gathered.

Just seem a thread here with dyno figures on the PE kit - around 200bhp which is respectable if its a case of low boost and an FPR.

 m http://www.mr2oc.com/66-spyder-turbos-e ... o-kit.html m

[Essex2Visuvesi]

It's a good setup giving boost from low rpms but it does seem to play a little "Russian roulette" with the fuel and ignition settings.

[lamcote]

Does anyone know what O2 mod on Spyderchat is that's referred to in the link above?

[MrT]

Hello gents
This is great info, thank you. I don't even aspire to get to that level of power, only fill the lower rpm range. Of course the engine will make more power overall but just looking to keep it simple. I thought of running 2zz yellow injectors and a return fuel line with higher pressure pump and a pressure regulator to tune the flow that way. The o2 should trim to correct thereafter. Again, only low power increase but improved driveability. I want to use water injection also, just a separate experiment, which will have the benefit of mitigating lean/hot combustion to some extent. Will require monitoring however.

E2V, I'd really appreciate the info you offered to end over, thank you. I will post any info relevant as I discover and verify it. I think I'll prove the concept on my worn engine to verify it is running decently before fitting to a good engine.

[m1tch]

Does anyone know what O2 mod on Spyderchat is that's referred to in the link above?

I think it refers to adding in some sort of screw in plug anti foul adaptors for oil burning engines, bored out to allow the fitting of an O2 sensor into a higher flowing exhaust system - the movement of the O2 sensor slightly out of the exhaust stream will apparently stop CEL codes.

OP - have you thought about a small supercharger change rather than a turbo - would give you low end and easier to fit than a turbo with plumbing as you aren't going big power.

[lamcote]

Thanks

[MrT]

Hi m1tch

I didn't specify what forced induction I intend to run. I plan to use an Eaton M60 (Merc 180 Kompressor) or VAG 1.4TSi supercharger. The VAG unit looks rather small but is ideally shaped to fit to the 1zz. But I'm almost certain it is not big enough as in the VAG application the turbo does all the work at high rpm... But my TSi has incredible driveability so it must be making decent enough boost at low rpm and technically would maintain that level of boost through the revs which is more than I want in this application. And these are cheap enough to try and easiest to install also.

[MrT]

Correction, the VAG supercharger is bypassed at higher revs, so pretty certainly too small to run on it's own. Looks like the Merc C180 K is the unit, also relatively easy to install but a bit more fancy Fab to fit it... I might try the VAG charger for kicks anyway.

[m1tch]

If you aren't after lots of power and are just wanting a bit more low end/mid range I would actually suggest a remap instead as it optimises the VVTi etc which will be better for everyday driving. Just an idea as it might be cheaper than going with forced induction - what mods do you have on the car at the moment?

[MrT]

Hi m1tch
Mods in my signature. Where can I get a remap of the stock ecu? I cannot find anyone offering this online and everybody seems to say it is a piggyback or stand alone ecu that is required.
My car already has pretty good pickup in the mid range and runs well, I just want a more linear delivery and to move some of the top end further down the revs. Plus light forced induction will help the volumetric efficiency of the engine and improve general efficiency at lower engine speeds.
And, I like superchargers and want to do it because I can to some degree.

[lamcote]

For efficient low boost at low to medium revs, isn't the M60 going to be too big? The M45 might be a better option?

[MrT]

M60 is a bit big but can be run a bit slower, there has to be a careful balance though. That is why I prefer the smaller VAG charger. I need to find out more info about that charger.

Back to the thread subject though, it seems worth a try with low pressure forced induction so I'll have a go. I must look into the Power Enterprise turbo setup, and any other threads referred to above.

m1tch, can you link me to a few of those threads you mentioned please?

Thanks

[lamcote]

Looks like the VAG is an Eaton M24 (interestingly with a gearing system). That probably is a bit too small though?

[1979scotte]

Not that helpful but there are plenty of people running 4psi through an Eaton supercharger on 1mz V6 on stock ECU without any other mods.

[onion86]

Where can I get a remap of the stock ecu? I cannot find anyone offering this online and everybody seems to say it is a piggyback or stand alone ecu that is required.

The general need for at least a piggyback in all situations is because the stock ECU can't be remapped, i.e. even just for exhaust and manifold changes you need something like a Unichip to get any kind of extra power out of it.

[spit]

Does anyone know what O2 mod on Spyderchat is that's referred to in the link above?

I think it refers to adding in some sort of screw in plug anti foul adaptors for oil burning engines, bored out to allow the fitting of an O2 sensor into a higher flowing exhaust system - the movement of the O2 sensor slightly out of the exhaust stream will apparently stop CEL codes.

Its more likely to refer to a conversion to a single O2 sensor. On the PE kit the O2s are both located post-turbo. The stock ECU treats their reads as bank specific when they're actually responding to the combined mix of both banks.

This is all well and good if the sensors perform identically and are subject to matching exhaust streams, but the slightest discrepancy where they switch from 0v to 1v can lead to fuelling epilepsy - the ECU will lean one bank right out and throw fuel into the other one. It then reads no change in the O2 readings so it carries on doing it. The result, at best, is a little stumbling off-boost. At worst its mechanically disastrous.

This is something we've experienced directly with three C2 kits and a couple of PEs.

[m1tch]

Where can I get a remap of the stock ecu? I cannot find anyone offering this online and everybody seems to say it is a piggyback or stand alone ecu that is required.

The general need for at least a piggyback in all situations is because the stock ECU can't be remapped, i.e. even just for exhaust and manifold changes you need something like a Unichip to get any kind of extra power out of it.

Has anyone tried to remove the stock chip in the OEM ECU at all? I swapped my stock chip out in my RX7 for a re programmable one which could then be remapped.

[shnazzle]

There's a company online that claims to be able to do this. Forgot what the name was as it seemed like a crock of s***.
If you did manage, you'd be the first one I think.
Something about the security that couldn't be passed.

[monsi]

What a coincidence I was looking at the TSI supercharger the other day! It looks like it would fit behind the engine without modifying the firewall, however it only has a very small capacity and will be spinning beyond its limits at about 4500rpm when only producing 6psi. I was going to use it in the same way as VW, a twincharger disconnecting, and bypassing it around the 3000-4000 rpm mark when the turbo is up and running.

In regards to the engine management, yes you can get away without a piggy back or standalone but you won't get the best from the engine.  I haven't heard anyone who has managed to remap the standard ECU, that includes TTE who used a piggyback on the factory turbo option.

The problem with using the standard ECU is that the ignition will be too advanced and you will be relying on either running way too rich or the standard ECU pulling the timing because it's knocking, neither are good for long term engine life.

[MrT]

Hello folks

Excellent info about the Eaton M24 and I found a forum thread of a transcript about the charger, I'll post that appropriately later.

But back to the ecu. I'll look but can,anybody else advise about a tuning firm or replacing the chip etc please? This sounds promising.

Thanks

[secla]

chipping the stock ecu was a common thing to do when i used to be into the old obd1 hondas.
never heard of it being done on the mr2 though

[alancsalt]

Even without further mods, just to get the gains you could from yr existing mods, install either a PFC or a piggyback system, and get a dyno tune. PPE headers alone are good for 6 whp with a tune.

Stock ECU non-tunable so owners can't change tune from emissions levels to best power.