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The mkiv Supra Owners Club

Quick BPU question....


Jim_1979

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Will have :

Double Decat + 3" exhaust

 

 

Am I right in thinking I still need FCD, colder plugs (really essential?), and fuel pump? (Walbro right?, again is this required with a JSpec TT?).... oh.. and a 1.2bar restrictor ring.

 

 

Sorry as I know this has been asked a million times, but I have done a search and couldn't find the information!!! :)

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Am I right in thinking I still need FCD,

 

Yes.

 

colder plugs (really essential?),

 

Change for some NGK's £4 or something - if you get misfire.

Alex did a good write up on plugs http://www.mkivsupra.net/vbb/showthread.php?t=41927&highlight=spark+faq

 

and fuel pump? (Walbro right?, again is this required with a JSpec TT?)

 

Yes. I don't think it's absolutely essential - but certainly a good idea, if your stock pump is tired.

 

.... oh.. and a 1.2bar restrictor ring.

 

Yes.

 

A boost gauge is a good idea - so you can keep can eye on your boost level.

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:) Yes Jim you will defo need a FCD because you wont be able to boost above 1 bar without it colder plugs are needed as is a restrictor ring too, but the Fuel pump is only if your Standard one has seen better days ive been told, do you have a Boost Gauge ? its needed to check the boost levels, Good luck :cool:

 

Cheers

Ian

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Will have :

Double Decat + 3" exhaust

 

 

Am I right in thinking I still need FCD, colder plugs (really essential?), and fuel pump? (Walbro right?, again is this required with a JSpec TT?).... oh.. and a 1.2bar restrictor ring.

 

 

Sorry as I know this has been asked a million times, but I have done a search and couldn't find the information!!! :)

 

If you plan to up the boost over 1bar then you will need a FCD. The stock ECU will cut fuel over 1bar, the FCD fools the ECU and prevents it from cutting the fuel.

 

Again, if you are planning on going over 1bar, then you'll need cooler grade of plugs fitting, to prevent misfire at higher boost levels.

 

Replacing the pump is a safety measure to ensure sufficient fueling. If you have the original j-spec pump fitted it will be quite a few years old now and may not be up to the job.

 

Yes you will also require a restrictor ring to limit the boost.

 

Also check the condition of your intercooler, if it is the original side mounted IC and is in poor condition (ie, blocked/crumbing/missing fins), then I would advise replacing this before upping the boost.

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If you plan to up the boost over 1bar then you will need a FCD. The stock ECU will cut fuel over 1bar, the FCD fools the ECU and prevents it from cutting the fuel.

 

Yeah, knew one would be needed. Need a cheap, good one!!

 

Yes you will also require a restrictor ring to limit the boost.

 

Where can I get one from and how much?

 

Also check the condition of your intercooler, if it is the original side mounted IC and is in poor condition (ie, blocked/crumbing/missing fins), then I would advise replacing this before upping the boost.

 

Yeah, I've seen some recent peoples stock IC once removedand they looked in poor condition. I had a quick look at mine yesterday and it looked in ok condition. Will give it another look over.

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Mechanical Boost guage about £70

 

FCD About £80 - for some reason you can get the Thor FCD from Miami GT cheaper than you can from Thor! :search: Well at least it was when I got one.

 

Restrictor Ring £20 from CW.

 

Walbro Fuel Pump about £70 - £80 off ebay.

 

Plugs about £5.

 

All of this is essential really - boost guage is a definite because the ring might not restrict you to bang on 1.2bar. All cars vary. Mine with the ring in only made 0.9bar. I had to get an electronic boost controller to up it some more - they're about £150.

 

All of the above prices are from memory so not exact. Going BPU always costs more than you originally think.

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and another question.... I'm semi-mechanically minded.... so how easy is it to change the stock cats over to the decats? The exhaust should be easily enough as long as the bolts move.

 

What about the decats tho? Where do they run, easy to get access to etc etc?

 

The CATs are just a bit of the exhaust too so if the bolts come undone you are away!

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am I right in thinking you could just use a boost controller and not a restrictor ring?? Could possibly get one on the cheap. :D

 

No you'll need the restrictor ring to limit the boost, a boost controller can only raise boost, it cannot lower it.

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Is a fuel pump needed? People say, only if your standard one has seen better days.
It shouldn't be needed IF your existing one is working like new. However, testing one is difficult/not worth the hassle.

 

But how would you know that?
You'd know if it's not up to the increased demand that BPUs put on the pump when the mixture goes lean and the engine dets itself to death.

 

Tbh, I don't want to spend £80 on something if it's not needed.
It's insurance really. If your stock pump is up to it you've saved £80 - if it ain't you'll quickly need a new engine.
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If you plan to up the boost over 1bar then you will need a FCD. The stock ECU will cut fuel over 1bar, the FCD fools the ECU and prevents it from cutting the fuel.

 

Again, if you are planning on going over 1bar, then you'll need cooler grade of plugs fitting, to prevent misfire at higher boost levels.

 

Replacing the pump is a safety measure to ensure sufficient fueling. If you have the original j-spec pump fitted it will be quite a few years old now and may not be up to the job.

 

Yes you will also require a restrictor ring to limit the boost.

 

Also check the condition of your intercooler, if it is the original side mounted IC and is in poor condition (ie, blocked/crumbing/missing fins), then I would advise replacing this before upping the boost.

 

How easy/hard is it to fit a restrictor ring ? I have a boost guage, but no restrictor ring.

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I'm decatted but with the stock exhaust (profoundly deaf wife). I'm currently at 0.8 bar- would I be right thinking if i bought a blitz SBC I could have the lowest setting at 0.8bar as it is currently, and then set the other three options for 1.0bar, 1.15bar & 1.25bar???

 

Obviously i'd change my intercooler first.

 

Thoughts?

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