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The mkiv Supra Owners Club

lots of boost


lambertpig

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just picked up the car after a full decat ,boost gauge and turbo timer the car is uk so i didnt get a restricter ring. result. 1.25-1.30 bar on way home at 4k revs couldnt work out if was getting fuel cut or not(too much wheel spin going on) was it traction cutting in?. so much for the uk waste gate was expecting 0.9-1 bar.have thor fcd to go on soon with boost controller and fmic. what shall i do? is it the almost freezing weather giving me so much boost? how much will it drop as it warms up? if it settles at 1.2 bar should i leave alone? or fit the controller

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Are you sure that there is no boost controller fitted?

If so, are you sure that there are no leaks in the pipes around the wastegate?

On the UKSpec you don't anything like 1.3bar just with a decat. You don't even get 1 bar in fact.

 

Is the boost gauge reliable? lol...

1.3bar and fuel cut didn't kick in?

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well yes.

What do you think a boost controller does, it regulates the airflow to the back of the actuator.

 

If the hoses to or from the actuator are leaking then it never pressurises and you can get into serious trouble pretty fast (if you have a heavy foot)

 

Also check that the wastegate VSV (at the front) is working. You never know.

 

But fuel cut shouldn't let you go that far.

If you DID go to 1.3 bar then there might be things that the previous owner didn't tell you.

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somethings definately wrong there my friend, i got my uk manual fully decated + wilson side mount and just hit 1 bar and if maintained for a couple of seconds would then hit f/c and you know about it when you do, so as john says check everything twice.

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just been out and checked all hoses they all look fine apart from that i dont know what im really looking at .cant see any tack on manual boost controllers.only fitted boost gauge today so dont know what it was boosting before decat-cat .was and still is running fine but now i worried about driving hard for fear of something going pop

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I think it's best to have someone more experienced have a look. Maybe your wastegate VSV is stuck open, who knows.

Someone who can also tell if you've already got an FCD.

Unfortunately you're too far from where I am (M25J4)

 

At least now with the boost gauge you know where you stand, and can be careful.

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As I suspected, you have leaks, deliberate or otherwise.

 

These above are VSVs and yes, they usually have pipes going to them (duh!)

The behaviour of the turbos will depend on how the missing ends of these pipes are connected.

If they are hanging out loose then the actuators never get pressurised (not good)

 

I don't like the look of this, looks like Botch City.

 

I suggest that you avoid boosting altogether until you have the setup verified by someone who knows what they're doing (i.e. a supra expert, not a general mechanic)

The first pic indicates that you may have no prespool for turbo #2 either (can't tell for sure from this pic though)

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Yep.

 

When I bought mine I checked that no boost controller had ever been fitted, and all hoses looked original and undisturbed.

Also that there had been no hanky-panky around the ECU either.

At least then you have an idea of the 'baseline' you are starting with.

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thanks john, were getting somewhere.ill nip it back to henstead motorsport they not supra experts but they do know a lot about turbos. anything more i can tell them.? are there any pics of uk engine bays on here i cant seem to find any?. wish you were round corner seems like you know the uk setup inside out. Richard

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JSpec setup is the same in this respect.

 

Be careful, I wouldn't let a non-supra specialist meddle with the sequential setup.

Surely there is a knowledgeable member around your neck of the woods!

You're near Norwich aren't you?

Maybe you can take it to IanC or Alex to have a look.

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I'm no expert far from it.... but i've recently fitted an electronic boost controller to mine (Jap not UK). I believe going by your photos, I removed the same hoses 'missing' from your set up but i needed to cap off the outlets. (This is due to the boost controller being connected directly to the turbo pressure outlet and the top of the wastegate actuator.)

 

Maybe the owner before you had an electronic boost controller fitted but ripped it out before selling it and didn't replace all the hoses?

 

to see where the missing hoses go, reverse this procedure.

 

http://web.archive.org/web/20050327033044/http://www.mkiv.com/techarticles/blitz_dsbc/index.html

 

hope it helps

 

if i'm wrong sorry for wasting your time...

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Indeed it looks like that's what they've done, among others.

 

In such cases you want the whole thing looked over by someone who knows what they're looking for, just to verify the rest.

They have also 'modified' at least the EGBV and the ECU, who knows what else is muddled...

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update on the boost. good news! a massive thanks to john and others who have put me in the right direction. a slow trip to henstead motor sport, the lads saw straight away things not right .in the work shop was a bog standard jap spec so a full check of all pipes and the addition of some blue pipes in the missing places and the result.quite amazing! it seems like the 1st turbo was not boosting at all ,low to mid range power/touque feels like its doubled. not sure how higher end power is but second turbo doesnt kick in so madly.boost showed about .9 bar and on the one stretch of fast road reached.925 at about 120. our conclusion is that as my car is a damaged repaired the 1st owner was bpu and he ripped out boost controller and other bobs taking the pipes with him.The salvaged car was then fully repaired in body shop without them realizing as car still ran(well but not as we know it) anywhy the car has only done 1500 miles scince and only 30 miles in crap weather without the cats so i dont think any harm done. so to conclude the car is not as virgin as i thought as far as mods go but now all is just fine. thanks again

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excellent.

 

With the first turbo making now boost, the second won't feel as much as a kick, because the 'step' will be less pronounced.

The car is faster however, even if it doesn't feel as such.

 

Did they check if it's got a fuel cut defender?

 

As for the 'virgin' bit, well, Madonna claimed to be like one and noone believed her, eh....

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no sign of fcd in footwell. however the lads confirmed that i do have rltc fitted i knew the button was on dash but as light doent work thought it may have been disconnected.again maybee it works and i dont realize, lets face it i didnt even know the first turbo wasnt making boost.they are going to investigate properly at next sevice.the day just gets better and better!.a big thanks to dave and rob at henstead motorsport who spent a good hour at a moments notice supplied the blue hose all for £25. what member has the silver veilside 620bhp single on 19 inch wheels in the workshop?.you should see the lambo diablo in for an engine rebuild with the lump out the back it looks like a pimped up pick up god that engine bay is big and the lump looked like a lancaster bomber engine sitting on the floor.mind you dave rekoned the car drove like a bag of shit and would have a jap motor anyday.i had to agree that it did have a kit car look about it close up. must cut down on the length of these posts sorry to bore

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