Cant Turn Up The Boost !

[boundsw]

Right, got my G-reedy boost gauge in, and working pukka !!

Only running 0.5 bar according to the gauge (about 7psi i guess)

so fitted my bleed valve between the turbo and the actuator.

Kept turning it up and up, bit by bit.

But at about 0.65 bar (between 0.6 and 0.7 anyways) I could not go anymore.

Now fuel cut on my car i think is 12 - 13 psi (MK2 Mr2 Turbo - Rev 1) so it aint that.

But even if i remove the screw from the bleed valve alltogether, it still wont go above 0.6 bar. (as if the feed to the actuator was total cut) and that would cause stupid boost levels !!!! (wouldnt it ?)

also, when driving it hits about 0.6 - 0.7 and then tails back off to 0.5 after about 4500 - 5000 revs.

Any ideas ?!?!?! - Actuator ?!?!!

[KiwiMR2]

vsv??

Cheers

KiwiMR2

[jaxx]

youll find you have peak and hold boost

basically it peaks at 0.6 bar then tails off to 0.5 before the next change, most turbos do it :)

[pizza boy]

Isnt limp home mode around 6psi..could be a sensor error causing the boost to stay at 6psi.? Also I know this sounds well obvious but are you using optimax/super unleaded? using 95oct can also limit boost exactly the same way you mentioned thru the rev range.

[boundsw]

Right Guys. Thanks for ya advice so far.

Yes I always use Optimax(98). (or BP ultima with octaine boost(99))

I have totaly disconected the VSV and blocked the feed to it with a 6mm bolt.

Also the feed from the actuator to the VSV has been blocked. (so it is no longer in use (so car should stay at one boost level - NOT use the two stage boost feature)

The bleed valve is between the actuator and the turbo, and the adjuster is REMOVED (not just fully adjusted) - the feed to the actuator may as well be cut !!- there will be no feed. Shouldt this cause stupidly high boost levels. But it wont go above 0.7 bar ??? - THATS WHAT I CANT UNDERSTAND ???

what is limp home mode ???

Cheers

[DeusMR2]

yes youre right you should get stupidly high boost if you removed the adjuster, but since youre only getting 0.7bar it must mean that your bleed valve is faulty (no surprise!)

you'd be better off getting a grainger (ball and spring) valve (~£24) and using that instead of the bleed valve. It does the same thing but its far more reliable and it doesnt leak air all the time like a bleed valve

Limp home/safe mode happens when the ECU detects too much knocking (low grade fuel/overheated air) or if the ambient temperature gets lower than about 5oC. In this mode The VSV is opened and the max pressure the wastegate will see is 6-7bar.

[boundsw]

Ok sounds good, cheers !!

I have heard of these Grainer valves and their advantages over a bleed valve, but i managed to 'aquire' this bleed valve so thought i may as well bang it on !

This all sounding promising though, as no one seams to think its my actuator, as i thought it might be.

so ill get me hands on a G-Valve and give that a go.

Ill keep you posted as to the results !

cheers guys !

[strange_days_uk]

Hello, I have this EXACT same problem. I installed a ball and spring controller, and even after turning it to maximum (over 50psi) the boost didn't go up from 9psi at all. Rev 2. I have a fensport FCD and delimiter installed. I figure I must have a leak somewhere, I hear a small noise at low revs when accelerating, that dissapears after 3,500 rpm. Does anyone know the solution. I have a reliable splitfire boost guage, I am really cheesed off at not being able to turn up my boost !!! :censor:

[DeusMR2]

sorry if its obvious but check that the valve is connected the right way round as this is a common error!

[strange_days_uk]

A had a Mitsubishi Starion turbo before with the same boost controller, so I have had experience of fitting them :)

Also, if it was the wrong way round, I would effectively blank off the tube to the actuator, and slam my beautoful engine with full boost :o

Someone please help!

[midmotorsteve]

A had a Mitsubishi Starion turbo before with the same boost controller, so I have had experience of fitting them  :)

Also, if it was the wrong way round, I would effectively blank off the tube to the actuator, and slam my beautoful engine with full boost  :o

Someone please help!

←

doesn't work like that, the little hole in the side starts to act like a bleed valve that just by coincidence gives you about 7 - 8 psi after the initial spike of 17 - 18psi.

[boundsw]

Right, have managed to turn up the boost.

But still think my actuator is not working peoperly.

have turned up the boost by removing the block from the actuator which originaly went to the vsv - so it constantly leaks, and the feed from the turbo to the actuator still has the valve in place (but it is fully wound in (should run standard boost).

I got it up to 1.1 bar last night (by winding the adjuster out) but have wound it back down to 0.9 bar (right the way in)

think im gonna get a fully adjustable actuator, and scrap the bleed valve!

I didnt hit fuel cut at 1.1 - which i thought was weird as my mr2 is only a rev1 (i thought) and they are suposed to cut at about 12-13 psi.

anyways - am gonna look into that.

Getting a knock link next i recon, so i can see whats going on.

but whats a "safe" amount of boost to run on a standard setup? Gear box, clutch etc dunno.gif

[BLOODUK]

1.1bar is pretty much your limit without risking things, i know a few people who have it at max 1.1bar with standard setups ie not including exhaust change

[strange_days_uk]

A had a Mitsubishi Starion turbo before with the same boost controller, so I have had experience of fitting them  :)

Also, if it was the wrong way round, I would effectively blank off the tube to the actuator, and slam my beautoful engine with full boost  :o

Someone please help!

←

doesn't work like that, the little hole in the side starts to act like a bleed valve that just by coincidence gives you about 7 - 8 psi after the initial spike of 17 - 18psi.

←

Steve, my valve does not have a bleed hole, so if it was the wrong way round I am sure that I would get full boost. Anyhow, either way I was VERY CAREFUL to get it the right way around. I have now ordered a turbo XS bypass (recirculating) valve to replace my stock one, because I am positive that is where the leak is. Having spent around £300 with Fensport to get the full silicone hose kit, as well as give the old girl a service, and getting no extra boost but better response I must admit, I am positive that the bypass valve is leaking. If this further 120 notes through eBay (www.boostparts.com in USA (gotta love the exchange rate!!)) doesn't work I will quietly retire into a corner of my garage and put a bullet through my head. It is the only honourable way.

Farewell cruel world ... <_<