Boost controller on bpu supe?

Hi guys

have read up a bit and still wondering...

what's the deal on a boost controller - do you need one to get to 1.2 BAR? if i dont have one will i only get to 1 BAR once i'm bpu?

i am going bpu soon on my jspec but havent heard any mention of a boost controller.... can some1 enlighen me purrrlease?

Ater decatting, the problem with the JSpec TT is actually restricting the boost to sensible levels. With a JSpec, you don't need a boost controller. A restrictor ring will do, although you can get more reliable boost control with the EBC.

My BPU Supra just had a restrictor ring, which held it at 1.2 bar most of the time. On very cold days, it did slightly overboost.

More info in the 'BPU thread', here... http://www.mkivsupra.net/vbb/showthread.php?t=94705

great thanx - so mine will boost to 1.2 BAR as soon as the decats are fitted with restrictor ring?

Assuming the ring is the correct size and you have a fuel-cut defender, yes. (Without the FCD, the ECU will cut your boost at about 1 bar. It feels like someone slamming on the brakes!) And make sure your fuel pump is up to the job. If it isn't you'll run lean and shorten the lifespan of your engine.

hi james

ill take you out in mine tomorrow,

im bpu so can show the difference with boost controller on and off,i think the difference is worth the cost.

ill give you a call about 9ish tomorrow.

ok?

baldy

On the J-spec Supra, removing both cats will increase the boost up to around 1.6bar or above without any boost controller fitted. Basically when the back pressure caused by the cats is removed, the small internal wastegate on the j-spec turbos is overwhelmed and is not able to flow enough exhaust gas to control the spool of the turbos so they overboost.

This is why a restrictor ring is used to create a restriction in the exhaust to lower the max boost to a safe level. Depending on the size of the hole in the restrictor ring, you could restrict them to 1.2bar and not bother with a boost controller. Or as I use to do on my old sequential set up, restrict boost to say 1bar and then use a boost controller to raise the boost as desired.

The turbos will boost higher in the colder winter weather compared to the hotter summer temps. Having some control of the boost allows you to adjust for this.

Also some of the more expensive boost controllers have features such as gain % and the ability to map the boost settings according to speed, throttle position etc. The gain feature helps spool up the turbos a fair bit quicker, meaning better response and reduced lag.

Normally you would set up your boost controller so you get peak boost when the engine is under the most load in a higher gear, but this will mean you get lower peak boost in lower gears (when the engine is under less load). eg. if you set up you boost controller to boost to a max of 1.2bar in 5th or 6th, you might only make 1bar in 1st and 2nd as the engine is under less load. Being able to map the boost settings against vehicle speed, allows you to set up the boost controller settings so you get maximum boost through every gear.

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wow!

thanx for all the comments guys - advise is greatly appriciated

i am getting a walbro 341 fuel pump fitted and a FCD, plus a restrictor ring so i gather that will stick me at 1.2 BAR......(which would suit me fine....cant imagine how much a 0.4 BAR increase from my current 0.8 BAR will feel but hopefully i'll feel it ok!!)

Baldy - sounds good fella, look forward to it - i'll be around from 10am