Found the source of boost problem.......

[neilA4]

I wouldn't mind if it overboosted to say 1.2 bar then held 0.9 bar, the boost seems to come down to 0.9-1.0bar in higher revs so may not be remapped. How does the ecu open? I have opened the ecu of my old calibra turbo to fit a chip before not sure if it's the same (motronic 2.7?)?

maybee a new maf and n75 would help?

or disconnect the n75 and put some sort of bleed valve in, or inline with the n75?

or get it mapped with bigger injectors

cheerrs

 

[aragorn]

The ECU just unscrews, 4 torx heads.

You can run a MBC in parallel with the N75 to stop it overboosting if you want, not ideal but it might help until its mapped properly?

 

[neilA4]

I'll try a new n75, the maf should be ok as it's reading high numbers? or could it be a bit slow? Would the mbc go in the actuator hose or turbo housing hose?

Will open the ecu tomorrow and post pics, hopefully has standard chips, not one with 'superchips' label lol

Thanks

 

[Broken Byzan]

That MAF figure suggests a remap as does the amount of boost you are seeing. Any idea what boost you had before the old turbo expired?

 

[neilA4]

Bought the car with a duff turbo i'm afraid! No history with it either! Car was cheapish so wasn't worried! Thought it felt slow though...

ECU open, i'm no expert but this chip does not look standard lol, anyone know its origins etc? cheers

 

[aragorn]

Almost certainly not standard imo.

Stock IC would be soldered to the board and certainly wouldnt have that little board with the regulator on it

 

[neilA4]

The label looks fairly old been in there a while methinks. Oh well, free remap! just got to get the overboost under controll lol

I may try a new n75, pcv and 710n.


cheers

 

[Broken Byzan]

if all else fails you will need a VR6 maf body and some injectors.

Giac does the encryption board IIRC

 

[neilA4]

if all else fails you will need a VR6 maf body and some injectors.

Giac does the encryption board IIRC

I was thinking about it tbh, wish i never sold my spare set of c20let yellows!

so 3bar fpr, c20let yellows, vr6 maf body, is there anywhere to get a 3" inlet pipe?

i'll try n75 etc first methinks

 

[aragorn]

Problem is if you try to run a 3" MAF on the existing map, your turning the wick up by a further 40%.

IMO you'd need to go back to the standard map if you wanted to just fit the new MAF and injectors...

 

[neilA4]

think i'll try and get this chip running right with new parts or mbc then, if it's the mbc way i'll set the boost to 1.2 bar max and be happy with 230ish bhp. It's a big difference from having no boost at all lol. Sean from scroll said 15 psi on the sp51r would make a reliable turbo, it's not designed to be a 'hero'.

If I fit the mbc in the actuator to n75 line, will the ecu still have controll over the boost?, but not be able to take the boost over the mbc setting?

When finished i'll put it on a dyno and see what afr and power it's making

Cheers

 

[aragorn]

The MBC needs to be in parallel with the N75 to set a maximum.

Like this: http://s4wiki.com/wiki/Manual_boost_controller