Bpu

[Terminator]

I might be wrong here but wasn't the term BPU first coined by Suprastore.com?

 

I believe so, and I thought they tried to claim copyright and stop other traders using it.

 

It is agood idea to fit and EGT gauge so you can keep an eye on temperatures at high boost when things can go lean and into melt down.

[Jake]

cool mate cheers, at least knowing that i dont need a boost controller will save a couple of hundred

 

since i have a kakimoto cat back all i need then is 1st decat, PLUGS, fuel pump, and FCD, restrictor ring

I use a boost controller anyway because I use a 1 bar restrictor.

 

Are you saying your exhaust has replaced the second cat? Unusual.

[Guest EncoreWRC]

I was told that if you decat the 2nd pipe then you increase boost pressures and can easily blow the j spec ceramic turbo's? thats why I was only thinking on the 1st de cat

[supraman.chris]

I have a Blitz boost controler and a restrictor ring, i've been told it stops 'spiking' that the controler can't cope with. double negative?

[moistfinger]

I have a TRD cat back exhaust and will be removing just the second cat at the moment.Will I need the restrictor ring/plate ? Or do you only need it when removing both cats?

J Spec TT VVTI

[Marco]

Isn't a boostgauge required for BPU as well?

[Jake]

I have a Blitz boost controler and a restrictor ring, i've been told it stops 'spiking' that the controler can't cope with. double negative?

It's the wastegate that can't cope with the increased boost that a decat provides. A restrictor restricts the flow (and therefore boost) to a certain level (What level depends on its apeture) and the boost controller then raises it from there upo to level you want.

 

I'm sure this is all in the FAQ somewhere.

[Homer]

I was told that if you decat the 2nd pipe then you increase boost pressures and can easily blow the j spec ceramic turbo's? thats why I was only thinking on the 1st de cat

 

Correct, thats why with a full decat you need a restrictor ring to hold the boost at 1.2 bar. The 2nd decat will cause too much back pressure to acheive 1.2 bar (i.e bpu) unless you have a boost controller to raise boost past this (Not advised due to increase in EGT). single decat with boost controller is an arse about face way of going bpu on a Jap spec. (Also, restrictor ring £15 vs boost controller £200 or so)

[Guest EncoreWRC]

and what boost can the standard J spec turbos handle safely?

[Jake]

I was told that if you decat the 2nd pipe then you increase boost pressures and can easily blow the j spec ceramic turbo's? thats why I was only thinking on the 1st de cat

Removing either cat will increase boost on a j-spec TT. Increasing boost increases wear and the chance of failure.

 

Removing both cats increases boost a lot. More than the wastegate can cope with. You can then use a restrictor in the exhaust to bring the boost down to a safer lever. (Typically 1.1 to 1.2 bar is ok)

[Guest EncoreWRC]

sorry - I m to slow on replying, just read your msg Homer. So I would jsut need to get a restrctor ring for £15 which would stop boost at 1.2 bar - sorted

[Homer]

and what boost can the standard J spec turbos handle safely?

 

Depends on your luck, 1.2 bar is generally accepted as the 'safe' limit. Some have gone a few thousand miles and lost a turbo, others (like me) have done over 30k and had no problems. Only thing I'd advise is to do it properly and ensure the car is ready for the increase of HP (All fluids replaced, all filters inc fuel, replaced, top condition IC, etc)

[Ewen]

Since theres experts posting at the mo....whats a loose budget for BPU done properly, inc. boost gauge and egt gauge but not inc. cat back exhaust ?

[Homer]

sorry - I m to slow on replying, just read your msg Homer. So I would jsut need to get a restrctor ring for £15 which would stop boost at 1.2 bar - sorted

 

Too many of us replying at once here

 

Correct though, if you do a full decat, you just need the restrictor ring to bring boost down to 1.2 bar (Or whatever else you specifiy). Chris Wilson highly recommended here!

[DannoSupra]

Soz for Hijack, i'l be getting my 1stcat removed this weekend, Seeing we're on the subject

 

What boost should i run. on UK. or Whats the Max Boost. i'll probs run at 0.6Bar - 1.0Bar on one setting and get a Race Setting

[Darren]

I have a TRD cat back exhaust and will be removing just the second cat at the moment.Will I need the restrictor ring/plate ? Or do you only need it when removing both cats?

J Spec TT VVTI

 

If you have a VVTI you can remove both CATs they dont suffer from boost creep. To hit 1.2 bar you will need a boost controller. HTH

[Homer]

Since theres experts posting at the mo....whats a loose budget for BPU done properly, inc. boost gauge and egt gauge but not inc. cat back exhaust ?

 

1) 2x Decat pipes = £280 from Chris Wilson (proper SS jobs)

2) Walbro pump = £80

3) FCD = £80 Thor highly recommended as it raises boost cut to 1.25 bar rather than remove it

4) Electronic Boost gauge = £150 - more for DEFI, if you have the cash

5) 6x plugs = £20 for hgk's, £65 for IK22's

6) Fuel filter = £30

7) ECU reset = Free

 

Prices are off the top of my head though!

[moistfinger]

Thanks Darren

[Homer]

Soz for Hijack, i'l be getting my 1stcat removed this weekend, Seeing we're on the subject

 

What boost should i run. on UK. or Whats the Max Boost. i'll probs run at 0.6Bar - 1.0Bar on one setting and get a Race Setting

 

You mention UK, so VVTI is out of the question

 

1st decat removal should see you to 0.9 bar, doubledecat won't make much difference to that. The UK has a larger wastegate than the Jspec so will require a boost controller (and all the other mods - except the restrictor ring) to raise boost to 1.2 bar+

[DannoSupra]

You mention UK, so VVTI is out of the question

 

1st decat removal should see you to 0.9 bar, doubledecat won't make much difference to that. The UK has a larger wastegate than the Jspec so will require a boost controller (and all the other mods - except the restrictor ring) to raise boost to 1.2 bar+

 

I'm seeing a Bar now, with only 2nd cat removed, and Apex'i AVC-R fitted

[Jake]

If you have a VVTI you can remove both CATs they dont suffer from boost creep. To hit 1.2 bar you will need a boost controller.

Really? I've never heard that before.

It's been that long since my VVTi was on the road I can't remember if I've tried it decatted and without a restrictor

[Homer]

I'm seeing a Bar now, with only 2nd cat removed, and Apex'i AVC-R fitted

 

Okay, you didn't mention the 2nd had gone already. Anyway, removing the 1st one won't make much difference without the controller, but as you have an AVC-R, it'll make no difference. You can set the AVC-R to see whatever you want, cat removal is irrelevant (Though of course its best to get those things out of there!)

[Darren]

You mention UK, so VVTI is out of the question

 

 

If that was aimed at me I was replying to moistfinger who mentioned VVTI in his own post? If not no worries........

[Homer]

If that was aimed at me I was replying to moistfinger who mentioned VVTI in his own post? If not no worries........

 

Oops, ignore my comment then!

[Darren]

Really? I've never heard that before.

It's been that long since my VVTi was on the road I can't remember if I've tried it decatted and without a restrictor

 

Oh yes they are same as UK in this regard...only quicker