my car wont boost over 21psi

**T5frankie** · Saturday 14th December 2013, 17:06

put the mbc on today, it is very un-nerving getting full boost at 2000rpms, papping myself in case i bend a rod lol, anyway my mbc doesn't seem to be doing anything, with it fully open it hits 21psi only in 4th and closed the same lol, strange thing is it felt faster with the bcs on, lambda light is off again after changing the fpr and ecu, so maybe ill try the bcs again

**graemewelch** · Saturday 14th December 2013, 17:19

thought you had forged rods

**cherry1809** · Saturday 14th December 2013, 17:23

He has, but it'd still be unnerving after what you're used to

**mitchyboy01** · Saturday 14th December 2013, 18:12

Exhaust back pressure may be blowing the wastegate open. Is it a stock actuator?

**stribo** · Saturday 14th December 2013, 18:19

You need a bigger turbo.

**merc85** · Saturday 14th December 2013, 18:19

Same maps inc the one i have still have a boost limit, mine is 22psi, and has been on the last 2 ecu's ive had

**AndysR** · Saturday 14th December 2013, 18:42

Two words.. Custom map...

**mitchyboy01** · Saturday 14th December 2013, 18:51

Originally Posted by merc85

Same maps inc the one i have still have a boost limit, mine is 22psi, and has been on the last 2 ecu's ive had

The ECU has no control over boost when you use a MBC.

**merc85** · Saturday 14th December 2013, 18:56

Originally Posted by mitchyboy01

The ECU has no control over boost when you use a MBC.

i beg to differ on that, both my old hlm ecu's cut the ignition at a sustained 22psi weird

**hybriduno** · Saturday 14th December 2013, 18:59

might be getting engine knock and retarding the timing. thus not boosting? have you seen what your afr's are under boost?

**t5 pete** · Saturday 14th December 2013, 19:03

Originally Posted by hybriduno

might be getting engine knock and retarding the timing. thus not boosting? have you seen what your afr's are under boost?

Checking the afrs would be very wise frank youve spent all this money and are missing a key thing to monitor the afrs

**graemewelch** · Saturday 14th December 2013, 19:04

take it to aet and get them to map it for you.

**smithy** · Saturday 14th December 2013, 19:27

You still have a boost limit even using an mbc because it works off the maf and knock sence too.

**Saaamon** · Saturday 14th December 2013, 23:01

Originally Posted by merc85

i beg to differ on that, both my old hlm ecu's cut the ignition at a sustained 22psi weird

My standard T5 with mbc won't boost anymore than about 12-13psi regardless of how much i try and dial it in so makes sense to me.

**mitchyboy01** · Saturday 14th December 2013, 23:18

Originally Posted by Saaamon

My standard T5 with mbc won't boost anymore than about 12-13psi regardless of how much i try and dial it in so makes sense to me.

My one would boost into oblivion with it's MBC. Strange.

**t5 pete** · Saturday 14th December 2013, 23:30

Originally Posted by mitchyboy01

My one would boost into oblivion with it's MBC. Strange.

Mine would also boost to what ever I would like with the ebc hence the bent rods

**Saaamon** · Sunday 15th December 2013, 00:19

Originally Posted by t5 pete

Mine would also boost to what ever I would like with the ebc hence the bent rods

Perhaps I'm doing it wrong then.. Probably best that it won't go that high as i didn't have an accurate gauge to set it up so instead used the force..... And the one on the dash.