[Mk2] [Turbo] Full boost at 5000rpm?

[CooperTurbo]

Hi all,

Having recently bought my first MR2 tubby, I inevitably have a few questions about boost!

The car is a rev 3 and running a Power FC as well as all the usual bolt on mods: Blitz exhaust, filter, smic etc...

It has been mapped by Ryan at 2Bar and has a graph to show 287bhp.

However,

According to the Apexi boost gauge, it only boosts to 0.5bar up to 5000rpm, at which point it seems to rise to just over 1bar.

The previous owner told me it was mapped to 1.2bar in cold weather and 1.1 in warmer conditions and I have no reason to believe otherwise.

Can anyone shed any light on why it takes so long to build boost?

[RyanRs]

sounds like either a boost leak, boost control solenoid failure or EBC has lost its settings... It could also be in Limp mode but you would get a check engine light with that on the dash and iirc a rough idle.

Check all the vacuum hoses are on , tight and not split. Go round the engine bay with the engine idling and squirt some carb/break cleaner about, if theres a split in a hose it will suck it in and dip the revs.

[Ryan S]

possibly a low boost setting? try playing about with the controller, my low boost setting is much the same as what you're describing

[CooperTurbo]

Ryan seemed to think it was a faulty actuator which could have been fouling the decat pipe potentially?

I don't think there is a low boost setting, but to be honest, this commander thing scares me!

So spraying carb cleaner should make the idle change?

How easy is it to check/change the solenoid and will it have a special one on it, as it's controlled by the Apexi ECU?

Any pictures would be a great help!

[jimGTS]

do you have a boost controller??

if so, what is it?

very few people run around on a apexi pfc boost controller, it is known as being quite crap, so people generally run there own separate boost controllers.
ryan would suggest this to.

if you have a separate one, it is NOT connected to the ECU in any way.

you need to know what you have so people can give any advice.


you should be giving US pictures, lol, not the other way around.

[CooperTurbo]

eBay item number: 221406138683

Seller assumes all responsibility for this listing.
The above link is my actual car (not allowed to post as a link due to being a NOOB!)

There is a blue Greddy boost controller , but I was told that this is not necessarily working, but still not to mess with it as it may conflict with what the ECU is telling it to do. He also states this in the above ad.

I'm pretty sure the boost is controlled by the PFC, as I'm sure the lad showed me that it boosts to 1.2 in cold weather and that it boosted less the warmer the air temp. His knowledge on the subject was limited, but he did say it's all controlled by the ecu.

Give me an n/a any day! First proper turbo car and whilst I'm loving the power, I HATE not knowing how my car works or how it has been built!

I'll try and take a a video/pics later!

[jimGTS]

you need to know what is controlling the boost.

by the sounds of things, nothing is for it to run 0.5bar and creep to 1bar.
either sounds like the boost controller is switched off (whatever is hooked up to turbo/actuator), or not working.

if the pfc solenoid (boost controller) is hooked into the ecu, then your looking at a remap to get back the boost it should or shouldnt be running.
personally id ditch it and rely on the profec.

if the other boost controller, the profec is hooked up, is it showing boost readings?? perhaps its just a glorified boost gauge at the moment (and its own solenoid isnt hooked up to anything).

[CooperTurbo]

Right,

I'm 99% sure the PFC is controlling boost, as I managed to enter the boost settings which shows how the boost pressure increases as the water temperate rises, with maximum being 1.2bar.

The profec spec I does nothing I suspect, but just lights up and 'looks' functional.

The boost reading on the commander showed a maximum of 1.1 bar tonight, but this did not happen til' around 5000rpm and it certainly made no more than 0.75 bar at any point before 5000rpm.

Is this likely to be a poor map or something not working quite right??

[jimGTS]

That doesn't confirm anything.

The commander will read boost whether you have a Pfc boost controller or another boost controller as that reading is taken from the oem map sensor.

You need to see what is connected between the turbo and actuator and where this leads to.


Whatever you have, boost control is not set up.

[CooperTurbo]

How many bloody posts do I need before I can post pics?! Such a pain!

[Ryan S]

How many bloody posts do I need before I can post pics?! Such a pain!

another 6

[CooperTurbo]

Best get spamming then!

...5 and counting