Do I have BPU or not?

Hi All!!

So chuffed today after picking up my new car from SupraGaz. It drives lovely, a much smoother ride than my GTS-T.

I am trying to work out how far along the road to BPU this car is at. It has an aftermarket boost gauge that peaks at 0.9 bar and a Blitz boost controller with Japanese instructions, so I am not touching it (but I'd like to know how it works).

It has what looks like a straight through exhaust which sounds lovely, and I can't see any cats under the car (unless I put his bowl under there I suppose ) and Gaz says it's had both cats removed.

Fair enough, but it passed it's MOT yesterday with no problems, is there any chance this could happen on a full de-cat?

Where is cat number one so I can do a visual check?

There's no FCD as far as I can tell - where would it be?

Finally, what would I need to do for full BPU - I am guessing, FCD and get someone to fiddle with the boost controller, and maybe get the RR swapped out, if indeed it has one, again no idea.

Dying to get out of work and drive her again now!!

FCD would be ontop of your ecu and that is under the carpet in the passanger foot well. You should be hitting over 1 bar with decatt mine hits the fuel cut at 1bar as I have yet to fit the FCD.

You should be hitting over 1 bar with decatt mine hits the fuel cut at 1bar as I have yet to fit the FCD.

Would the boost controller be limiting the turbo to 0.9 or something like that though?

Why not ask Gaz how far he had got and what parts he had fitted etc?

Would the boost controller be limiting the turbo to 0.9 or something like that though?

A BC can only up boost, not limit it.

Why not ask Gaz how far he had got and what parts he had fitted etc?

Yep I of course have the full run down from Gaz but he had inherited the car "as is" himself, so there may be some differences, I mean on an 11 year old car it's hard to capture *exactly* what's been done.

Prime example being it's apparently full de-cat but still goes through an MOT so I am not sure if it's true or not...

Worth pointing out that nothing I say on this forum is any dig at Gaz or anything like that - I've got an amazing car from him and can't fault it, but I plan to get my hands a little more dirty with it

A BC can only up boost, not limit it.

OK - nice one. So chances are I have a RR or a Cat restricting my boost?

I would think that it has a restrictor ring that is limiting it to 9.0 bar and the boost controller is for upping the boost, but may be disabled due to fuel cut, and yes my car passed MOT without any cats.

Why not ask Gaz how far he had got and what parts he had fitted etc?

I never touched anything to do with engine (Except keep it clean )

It is how I bought it so dont know whats been done. Dont think it has a FCD but know it is double de-catted, has a Blitz dual SBC and a boost gauge dash mounted. Always kept it at 0.9bar as daily driver

Gaz

OK - nice one. So chances are I have a RR or a Cat restricting my boost?

if it has decats in and youre only hitting 0.9 it must have a restrictor, or maybe the front cat is still in.

the older supes can get through emissions tests with both cats out. The newer ones can too if you go to the right place!

a pic of the underside of the car and im sure someone will be able to tell you if the cats there or not...

I would think that it has a restrictor ring that is limiting it to 9.0 bar and the boost controller is for upping the boost, but may be disabled due to fuel cut, and yes my car passed MOT without any cats.

If I can work out how to work the boost controller, I can try setting it higher perhaps, and see if I get fuel cut?

Good to hear about the MOT though

I never touched anything to do with engine (Except keep it clean )

And a good job you did too. The engine bay looks as good as or even better than my Audi did at 1 year old.

Sent you a PM by the way.

This is a pic of the 2 cats (US ones but similar to the J-spec)

The small 1st cat is closest the engine, the longer 2nd cat goes underneath the front seat area of the car.

If you're only making 0.9bar then you have either got one of the cats still in place or a restrictor ring limiting boost.

What boost controller is it? Post a pic if you're not sure and perhaps we can find you some instructions.

This is a pic of the 2 cats (US ones but similar to the J-spec)

 

The small 1st cat is closest the engine, the longer 2nd cat goes underneath the front seat area of the car.

 

If you're only making 0.9bar then you have either got one of the cats still in place or a restrictor ring limiting boost.

 

What boost controller is it? Post a pic if you're not sure and perhaps we can find you some instructions.

 

[qimg]http://mkiv.com/techarticles/downpipe_pics/stock_cats/mvc-006s.jpg[/qimg]

Cool thanks!

I looked under the car earlier and it definately looks like one long drainpipe from the back to the engine, no cats visible. I thought one might be in the engine bay, obviously not *grin*

It's a Blitz Dual-SBC, with an LCD in the car showing the current boost. Two buttons/knobs on it...

See instructions for the boost controller attached. An easy way to check if you have a FCD fitted would be to up the boost over 1bar, if you don't have a FCD then the ECU will cut the fuel.

Dual SBC Spec S&R.pdf

You may find that you dont need a boost controller on a JDM Supra when you have a double-decat (DD) and RR, most will boost to 1.2 bar without any need for a boost controller.

I have a boost controller on my JDM TT, but its never used as the DD and RR was enough for me to see 1.2 bar.

That is such a lovely car. Pristine Gunmetal 6sp, yes please

Enjoy matey.

You may find that you dont need a boost controller on a JDM Supra when you have a double-decat (DD) and RR, most will boost to 1.2 bar without any need for a boost controller.

 

I have a boost controller on my JDM TT, but its never used as the DD and RR was enough for me to see 1.2 bar.

Well if you are giving your BC away just let me know...

Hi All!

Have been away for the weekend, had a lovely trip down to Devon and *definately* proved the car ( 2 adults in the front + camping gear in the back!)

Am defaintely double decat - my knowledgable friends down there could tell from the incredible noise from the engine/exhaust.

I will have a look at the instructions for the boost controller, Nic thanks very much.

For some reason on the way down to Devon while giving it some beans in 4th gear on the motorway I got fuel cut. Scared the willies out of me because it sounded like something in the engine going clunk!

Reproduced it again and I got to 1.01 bar according to the readout before it happened again - perhaps the extra load in the car caused everything to work a bit harder.

Got some great stares by the seaside

Unless you know exactly what you're lookinh for its almost impossible to see if the first cat is still in place looking under the car. Are you able to take a pic of the exhuast looking down at it from the top of the engine bay?

Sounds like you have no FCD, so add that to the list Don't forget about the fuel pump too (Also make sure the fuel filter has been changed in the last year or two).

Unless you know exactly what you're lookinh for its almost impossible to see if the first cat is still in place looking under the car. Are you able to take a pic of the exhuast looking down at it from the top of the engine bay?

 

Sounds like you have no FCD, so add that to the list Don't forget about the fuel pump too (Also make sure the fuel filter has been changed in the last year or two).

I can certainly take some pictures. Also going to get her up onto a 4-post lifter this week sometime to have a good ogle.

Certainly seems like fuel cut. It was a "thunk", and loss of power, and I got a warning light on the dash for about 10 - 20 seconds afterwards. Does that sound about right?

Agreed with Homer. Check that the fuel pump has been changed or is in fab condition (flow wise) before running it to 1.2 bar.

Also - do you know what plugs it's got in? They may not be too happy at 1.2 bar.

Certainly seems like fuel cut. It was a "thunk", and loss of power, and I got a warning light on the dash for about 10 - 20 seconds afterwards. Does that sound about right?

Yep, thats fuel cut alright. It's quite a shock the first time it happens eh?

Agreed with Homer. Check that the fuel pump has been changed or is in fab condition (flow wise) before running it to 1.2 bar.

 

Also - do you know what plugs it's got in? They may not be too happy at 1.2 bar.

I will take a look, thanks. AFAIK it's got "normal" plugs as it was serviced here in Feb and the plugs would have been changed then.

Will be safe and buy some colder ones anyway. Is the current recommendation still IK22s?

Yep, thats fuel cut alright. It's quite a shock the first time it happens eh?

Hell yeah. It was exactly the same feeling I got when I sheared off the injection pump tensioner in my old A6 after dropping a couple of gears too many on the M5 while overtaking a few years ago!