Boost gauge installation MR2 + MR2/3sgte boost questions

[Chickenman]

Ok, where's the best place to take a feed for a mechanical boost gauge?

Can I take it from the hose that's currently feeding the indash gauge?(therefore disabling it)

Some pics coming soon.

[Al]

Yeah take a feed from the boost pressure sensor hose, just tee it in there. You can remove the boost pressure sensor hose from the manifold and plug in your vacuum hose there but you will lose your boost cut at ~12.5psi and the stock gauge wont work. I wouldnt advise pulling the pressure sensor hose unless you have reliable boost control.

There should be a spare grommet on the drivers side firewall that you can run your vacuum hose through to the cabin, then just run it up the right hand sill

[Chickenman]

Thanks so much Al, I notice there's a filter in that line... do I tee it pre or post?

[Al]

Im pretty sure mine was on the manifold side this is going back a while...

I dont have a boost pressure sensor hose anymore....its open to the air

[Chickenman]

Cheers bro... no biggy to ty either way, will try manifold side first.



Cheers.

[Chickenman]

So anyway...

I'm sure there's something wrong.

Boost pressure as follows..

Idle = -20 (vac)
1st,2nd,3rd gear all pretty much = 6lbs boost at around 4000-5000rpm
4th&5th will reach and hold 8lbs till about 5000rpm before it tapers off.

I checked my lines etc.. and the factory gauge is still reading the same as it used to (right up to the plus in 4th and 5th).

Maybe my gauge is shit? or maybe my turbo is poked?
Or could it be stuck in low boost mode?

0-100 is about 7.5 seconds.. (changing just after 5200rpm)

[Dell'Orto]

Is your VSV still plugged in?

[Chickenman]

Dunno....

Where be that?

[Dell'Orto]

ah ok, you know where the actuator is? there are two hoses coming off it, the right hand side one (think? have to check) should be hooked up to the VSV, its like a form of boost control.
Just check both the lines on the actuator, make sure they're connected at both ends.

[Chickenman]

Yeah, that looks fine.

I changed the stink brass pipe that came with the gauge for a nice piece of hose... works better now, I think there's still a bit of a problem with the connections.

I'm guessing full boost reading at about 9-10 is right? (after the pressure drop across the i/c...) or should it be 10-11.

It's still only hitting 6-7ish in the first couple gears...?

Anybody got figures for comparison?

[mr2_t]

Heres a link to my dyno chart - stock SW20 turbo, with a gutted cat. 10 PSI is where it tops out generally.

http://rjm.no-ip.info/stuff/dyno.jpg

[RBRCHKN]

chinken man ya dirty poon tank

my sw has a bit of a problem that sounds similar. sometimes it wont go above 6 psi but then all of a sudden it will go back to normal and top out at about 9 psi

[_will_]

sometimes it wont go above 6 psi but then all of a sudden it will go back to normal and top out at about 9 psi

I have the same infuriating problem with my GT4. And it just seems to happen at random times

[fivebob]

chinken man ya dirty poon tank

my sw has a bit of a problem that sounds similar. sometimes it wont go above 6 psi but then all of a sudden it will go back to normal and top out at about 9 psi

Either the engine or air temp is too low, or more likely the ECU senses knock, and retards the timing and activates the T-VSV to cut boost.

[Chickenman]

I actually got the good ol' limp mode the other day... Gas up here is pretty shit, I do find Gull a little better though.


Still not boosting over 9 on my gauge.. even in the cold tonight.

Not too worried though.. still having heaps of low speed fun


So,

Cambelt and shizz

dyno run.

New turbo... or get this one reconditioned? What you guys think?

It's not that I really want more boost, I just want a more sustained boost. (Right through to 6-7000rpm) where as it's dropping off to 6lbs at higher revs.. totally useless in first really.

[Chickenman]

Heres a link to my dyno chart - stock SW20 turbo, with a gutted cat. 10 PSI is where it tops out generally.

http://rjm.no-ip.info/stuff/dyno.jpg

Much of a mission to gut the cat?


*Google... help me*

[fivebob]

I actually got the good ol' limp mode the other day... Gas up here is pretty sh*t, I do find Gull a little better though.

Please define what you mean by limp mode, did the Check engine light come on?

New turbo... or get this one reconditioned? What you guys think?

It's not that I really want more boost, I just want a more sustained boost. (Right through to 6-7000rpm) where as it's dropping off to 6lbs at higher revs.. totally useless in first really.

You won't make much boost in first and second, there's not enough exhaust flow to push the turbine, but you should be able to make more than 6psi even with a CT26, have you checked for boost leaks?

New turbo, just by a CT20B, cheapest option, $750 for a used ceramic one or $1500 for a new steel one.

Much of a mission to gut the cat?

Not really, but sometimes they can be a bit stubborn about coming out so it can take a few hours.

[Chickenman]

No check engine light...

I was ascending a hill in second and it must have begun knocking significantly enough for the ECU to both retard the timing and kill the boost. Car was fine after sitting for a few minutes.


Although your answers are very succinct and helpful fivebob, I get the feeling you hate me... please don't hate me.

I'm just a lonely penguin

[Twolitre]

When gutting the cat I advise you to wear a decent face mask as I've been told the dust can be toxic to your health, and containing precious metals such as paladium etc I can probably believe it although some people swear by saturating the honeycomb in oil to keep the dust down however I've have best results seperating the cat housing and knocking it out in one piece through the top with a tire iron and a decent hammer through the other side.
Does the turbo actually need replacing? If not I'd start with the basics first and get the car fully up to scratch with new filters/fluids/leads etc and go from there, 140+rwkw should keep you entertained for at least a while!

[Chickenman]

By the sounds of it it doesn't need replacing, doing the basics over the next week.