Standard boost on evo8

[neilbm10]

Does anybody know How much boost does a standard evo8 fq300 run?

Also at what level does over boost cut kick in?

Just intrigued really as hit boost cut when De'cated recently

 

[fq-craigus]

1.2bar peak drops to 1.1 ish boost cut for mine was about 1.3/1.4bar the colder weather will be causing this not the fact you have decat now, the air is denser so basically more of it and its nice and cold.

did you post this over on the mlr too? think i posted on there saying sbout a controller and remap

 

[neilbm10]

Cool cheers, no wasn't me on mlr,
It only happened once on Saturday just after I fitted the decat plus was absolutly freezing out so iam putting it down to both.

 

[Dirtmatt]

as craig said.. A fq330/340 will run more boost.. fuel cut is closer to 1.5bar as it peaks 1.3-1.4

cant see it just been cold air creating fuel cut! would have to boost over the peak limit for a few seconds for fuel cut to happen. A spike in pressure shouldnt cause it.

You altered anything else or just the decat?

 

[neilbm10]

Nah the car is completely bog standard.
I put it down too:
no cat, no back pressure easier spool and slightly more boost
Freezing cold air, more dense more air etc.

It's warmer out today so I bet if I drive it now it would be ok.

 

[Dirtmatt]

All that and boosting lower down the rev range in possibly a higher gear?

 

[neilbm10]

I'm sorry mate, I'm not too sure what you mean?

I was booting it in either second or third when it occurred.
After it happened I just drove home at a casual pace, no hard acceleration or anything.

 

[Dirtmatt]

I'm sorry mate, I'm not too sure what you mean?

I was booting it in either second or third when it occurred.
After it happened I just drove home at a casual pace, no hard acceleration or anything.

I meant that if you put your fllor flat to the floor from about 3k revs in a higher gear there is more chance of over boosting.

that wouldnt be fuel cut! not if you were driving at a casual pace. No boost gauge in the car?

what exaclty happened?

 

[neilbm10]

All that happened is:
I De'cated it.
Went for hot lap
Weather was freezing
Booted it in second gear
Hit boost cut.

So to remidy till I get it mapped I've refitted cat.
Today ive proved it was decat by:
Refit cat
Went on hot lap
Booted in second, third, fourth, fith several times and no boost cut.
It's still cold out maybe even colder.

So to summarise, it was boost cut and was present due to both the decat and cold weather.
If perhaps I had fitted it in the summer may never have noticed due to warmer ait's

 

[Dirtmatt]

Amazed that a decat would cause too much boost!

Least its sorted mate

 

[fq-craigus]

Glad it's sorted. Still confused, I know you have done a little test and seems conclusive but a decat doesn't control or effect the air going into the car, only frees up it breathing out. Would a decat cause boost spike? Anyone?

 

[Dirtmatt]

Glad it's sorted. Still confused, I know you have done a little test and seems conclusive but a decat doesn't control or effect the air going into the car, only frees up it breathing out. Would a decat cause boost spike? Anyone?

Well less back pressure will promote quicker spooling so possibly the boost controller could act quick enough to rein it in but still can't see it having enough of an effect to get fuel cut..

 

[andymrfq320]

a simple decat can cause this yes, some do some don't, look of the draw i think and sometimes depends if other mods need to be considered.
Fitting an IBC and setting it to run standard boost solves it, others wise a re-map.
Cheers Andy