35 replies to this topic

[kr0nic]

Hey Guys, Can anyone tell me what boost a B4 should be running from the factory ? My B4 was stock standard when i bought it a few months ago. Iv just installed a Hybrid Boost Controller + Gauge , according to the gauge im hitting 17 psi in fourth gear with the foot to the floor.... is this correct ? I would of thought stock boost would of been much much lower then this, somthing like 7-8 psi.

[Mosti]

17 sounds abit high, although I've never tried it in 4th. My B4 is stock apart from CAI and in 3rd it runs between 12-15 PSI on primary and 10-13 on secondary. Thats the beauty of the B4, never boosts the same lol!

[robt]

Well my GTB ran 10psi on the primary and 13-14psi on the secondary with the stock ecu. Now with my Mines ecu it hit a rock solid 12psi/16psi. I am sure they are similar boost levels from Gen2 to 3.

[Jimbo]

i dont get how the B4 runs less on sequential .. weird tuning .. my GTB on stock ECU with 2.5" dumps with vf25/27 runs ~15psi on primary then ~20psi on sequential .. that would suck to get less boost on sequential in a b4 ??

[hawks_123]

Thats the beauty of the B4, never boosts the same lol!

Yep, you never know what to expect

[B4TT]

Mine stock is around 9 - 10 PSI tops stock exhaust, intake etc.

[legacy rsk]

dont know how to work out the primary and the secondary boost but stock on my car is 1.01bar, but i run a hks evc-s and it now runs 1.2bar

[thatsgoodsquishy]

Mine hit 14psi on both (primary and secondary) when stock, i now run about 16 via a greddy EBC. You find boost cut at 18, well i did.....

[Dylan]

I think Will's (Brendan's old) B4 runs around 15 PSI on primary and 18 on secondary and that thing loves it! It is tuned, but it seems to handle that quite well.

[Jimbo]

dont know how to work out the primary and the secondary boost but stock on my car is 1.01bar, but i run a hks evc-s and it now runs 1.2bar

Just work out what you get when the primary opens its wastegate before sequential, so say 15psi, then open it up onto sequential and see what you get then, more or less depending on how wacky your setup is. I run a second boost guage off the vaccum line on the top of the "horseshoe" where the secondary BOV is and see it up to 15psi on its own but imagine most of that is bled off. I really use that guage on the secondary to moniter the ECV anyway so its not an issue for me if it isnt accurate. But by reading my manifold guage i get 15psi then it drops to about ~8psi when sequential starts then it winds to ~20psi at full noise.

[hawks_123]

20psi

[Alex]

anything under 20psi is fine. don't sweat it.

[Delete This Account]

Im still yet to check to boost on mine, just a quick one, with the tunes (ecutek) do they 'up' the boost? Or just change all the other settings? im not sure how it work, but i know it works

[robt]

Im still yet to check to boost on mine, just a quick one, with the tunes (ecutek) do they 'up' the boost? Or just change all the other settings? im not sure how it work, but i know it works

Boost is upped, timing is usually dialed in and rev limit raised. Usually if your car has been tuned it can handle heaps more boost safely.

[Delete This Account]

rev limit raised.

Is the normal limit at 7500? cause ive noticed it seems to rev a little over that, maybe to 7800

[robt]

Some tachos read inaccurately but yes the limit will be about 7800rpm. My car has a 7000rpm limit on the stock ecu but it has been raised to 8000rpm with the mines ecu.

[Delete This Account]

I wouldnt mind a 10k limit

[robt]

At 10000 it will out of its power band. It would have fallen off boost and just use revs for power then bang! My bike only starts to pull hard at 10000. Turbos are all about midrange.Oh and yes

[Chadza]

Hey walts- I should post up a scan of the back of my Dyno graph with the boost graph on it from my Ecutek 2 tune. I assume you got yours done at Sean's as well? Here are a few different spots where I can compare boost before and after the ecutek. Peak boost on primary- Before- 12psi (Average before changeover- 12psi) After- 11psi (Average before changeover- 10.5psi) During changeover- Before- 8.5psi minimum After- 9psi minimum On Secondary- Before- 10.5psi max (average 10psi) After- 16psi max (average 15psi)

[Delete This Account]

Cheers for that info mate, yeah mine was done at S&J as well by sean