What boost are you running?

[scam75]

I cured a slight hesitation on full boost last night with fresh plugs, cap and arm. Been a good while since I've did a wee road test on WOT. Noticed I am making about 18psi in 3rd, 19psi in 4th and 20psi in 5th on WOT. AFR's all good.

I am running Promax L2 chips and all the stuff you see in my sig. I have spoken to Promax before and they say the maps on the chips are good up to 21/22psi as long as the fuelling is ok. I am running a freshly rebuilt K26/8. I did a quick bar to psi check and 20psi is nearly 1.4 bar. Is anybody else running this sort of boost. My car has been running like this for 13k miles since my engine refresh and has never missed a beat.

Cheers

Stuart

 

[blade7]

Spiking to 20 psi for seconds on a 26/8 you may get away with it for years. Try that for extended periods and you will be creating a lot of heat that will most likely have consequences.

 

[scam75]

Kinda thought that buddy. My car isn't particularly hard driven at all. I just like to know what's on tap for when the moment grabs me!

Stuart

 

[blade7]

It's hard to hold full throttle in top gear for very long on the Queens highway these days. With the standard turbo/exhaust there comes a point where more boost just adds heat rather than power, I'd knock the boost back to 18lbs or modulate the boost with the throttle if it strays higher in top gear.

 

[944 man]

/MBC
EBC

 

[scam75]

MBC Simon.

As mentioned WOT in 5th doesn't happen much on the road and if it does it's not for long, it's only making 18/19 in 3rd/4th so think I'm quite happy at that.

Stuart

 

[zcacogp]

I have a reliable 14.7psi, but it drops when I go up some big hills.

No misfires at all; always runs smoothly, even on extended periods of WOT.


Oli.

 

[scam75]

ORIGINAL: zcacogp

I have a reliable 14.7 stoic AFR at idle, but it drops when I press the loud pedal.

No misfires at all; always runs slowly, even on extended periods of WOT.


Oli.

Fixed it for you. Can't have you being banned for getting your AFR's and your boosts all mixed up! []

Stuart

 

[zcacogp]

ORIGINAL: scam75

ORIGINAL: zcacogp

I have a reliable 14.7 stoic AFR at idle, but it drops when I press the loud pedal.

No misfires at all; always runs slowly, even on extended periods of WOT.

Fixed it for you. Can't have you being banned for getting your AFR's and your boosts all mixed up! []

You, sir, are a git of the very first order! []

(There - the mods can ban me for calling you a 'git', even if they can't ban me for getting my AFR's and boosts mixed up!)


Oli.

 

[zcacogp]

BTW, I love a good Boost myself.

Particularly the chewy toffee around the edge.


Oli.

 

[scam75]

ORIGINAL: zcacogp

BTW, I love a good Boost myself.

Particularly the chewy toffee around the edge.


Oli.

Just keep it out of your intercooler and you'll be fine!

Stuart

 

[zcacogp]

ORIGINAL: scam75
Just keep it out of your intercooler and you'll be fine!

Stuart

On the contrary, I always keep chocolate in the fridge as it makes it crunchier and harder and tastes better. []

Admittedly, I don't have a fridge in the car though.


Oli.

 

[944 man]

I meant: time to ditch the Dawes or whatever type of MBC you have and fit an electronic boost controller.

 

[scam75]

ORIGINAL: 944 man

I meant: time to ditch the Dawes or whatever type of MBC you have and fit an electronic boost controller.

Oh right yes makes sense now!! Never really thought about an EBC. I do get a little drop off due to the MBC as I approach the red line, but for the amount of times I require to hold full boost to the red line (zero that would be!) I never felt the expenditure or bother to fit it was needed.

I imagine what I get is typical of an MBC shod car.

Stuart

 

[Suffolk944]

My boost is more around the 1.35 bar figure albeit with a non-standard turbo charger plus other bits as below and an EBC which is a great bit of kit. []

 

[Eldavo]

Boost profile with a MBC set to 18psi, spiked at 19:

Boost profile with an Apexi AVC-R EBC, set to 18psi (scale on the left is different):

A nice improvement in the AFR for Oli too []

 

[Frenchy]

What EBC comes recomended then ?

 

[Eldavo]

The Apexi is the dog's dang lies but I probably won't use half the features, plenty of adjustability though so I can tweak it with familiarity. The Greddy Profec series is pretty good, sey a high and low boost and then let it get on with it.

 

[ChasR]

I shall be keeping an eye on this. For similar reasons (spiking) I plan to buy an EBC in the future .

 

[Eldavo]

The Greddy units do a good job at working towards a target boost and holding it there as long as possible. The Apexi lets you vary boost by gear and alter the boost curve based upon rpm signal too - hence my boost curve in the dyno plots is smoother as I have it more progressive now and turned down in 1st and 2nd gear as well.

The other advantage to a EBC is that you can choose between high boost, low boost or just the wastegate spring pressure in seconds. I use High boost for dry roads/track, low boost for damp/wet conditions and wastegate for motorway/friends driving