Adjustable fpr - vacuum hose

[SpecB]

While blanking my BOV I noticed that the vac pipe from the inlet manifold to my adjustable fpr (fuel lab) had perished and fallen off, I hadn't noticed any real issues with running, any ideas what issues it may have caused?

Just so I understand it what does the vacuum pipe connection do to the fuel pressure?

[Scott.T]

Sorry to say it would of been running lean when on-boost 'IF' when it was mapped the hose was in place.

With the Vac attached, as boost rises so does the fuel pressure i.e if at Idle and approx -0.5bar vacum the fuel Pressure is 3bar, then at 1bar boost fuel pressure will be approx 4.5bar. With the hose off it would still be sat at the idle level regardless of boost.

[C. J.]

Originally Posted by BlueBugEye

Just so I understand it what does the vacuum pipe connection do to the fuel pressure?

Adds fuel pressure at same rate as boost so boost 1 bar it adds 1 bar of fuel pressure . As for your engine it could have ended in tears

[SpecB]

Think I may have had a lucky escape! But may have explained the knock that Syvecs picked up at Goodwood, no idea when the hose gave out, the cars been sat a while so may have gone while it wasn't used but can't believe it wasn't gone for the last meet. Will have to take it out tomorrow to see.

Car was mapped only a couple of days after the hose was fitted so pretty sure it was ok for the mapping, I've not noticed any loss in power and having a open vent on the manifold really should have affected something in an obvious way I guess?

[Scott.T]

I wouldn't expect a hose to perish that quickly, unless already old or poor quality.
You should ideally get the fuelling checked once you refit the hose as it may now be overfuelling if the hose was off during mapping.
Looks like you may be adding the Bug to the RR day for a health check and comparison the AFR against your previous plots.

[SpecB]

Took the at out tonight for a couple of runs - will pull the logs later today but was running live data to the laptop, on full boost WoT runs lambda dropped to 0.780 at the lowest, was at 0.996 idle I'm not sure if low is rich or lean and how far from 1 it should go?

[Scott.T]

sounds like its in the right ballpark running just under 14.7afr at idle and 11.46afr at wot. i normally map to 11.2/11.3afr but a built engine can run a touch leaner. if there's no indication of det then its probably fine.

did u say u saw det on the goodwood trackday ?

[jura11]

Hi there here is the Lambda to AFR conversion table




Knock can be engine noise,gearbox or something touching the manifold etc.Without the det cans you never know for sure what can be or cannot be.

Just check the logs and have look for ignition retard and how much ignition retard pull Syvecs when you are get knock,second thing when you are get knock,have look when this happen if is under load or gear shifting etc

Jura

[SpecB]

Had a cel thrown on (set as knock indication in Syvecs) on the straight after I hit the limiter (damn JDM box) so had the ignition pulled by Syvecs.

Only ever had any hint of knock on track and usually when I over rev the engine!

[C. J.]

Speak to Simon

[Scott.T]

Originally Posted by BlueBugEye

Had a cel thrown on (set as knock indication in Syvecs) on the straight after I hit the limiter (damn JDM box) so had the ignition pulled by Syvecs.

Only ever had any hint of knock on track and usually when I over rev the engine!

If your pipe was off on track, that would explain it.
When it goes on the rollers just ask Charlie if he can have a good listen for det and double check the RR AFR plot for fuelling against your road logs.

[Scott.T]

DOH!!! Ignore the above, just noticed you have pulled out 'AGAIN'

[SpecB]

C.j. I've spoken to Simon well did a long time ago after I got the 'knock' warning at Brands it appears my engine triggers the Knock on Syvecs if I hit the limiter, there's no hint of det on the rollers or road.

[Jolly Green Monster]

Originally Posted by BlueBugEye

Had a cel thrown on (set as knock indication in Syvecs) on the straight after I hit the limiter (damn JDM box) so had the ignition pulled by Syvecs.

Only ever had any hint of knock on track and usually when I over rev the engine!

obviously there is a lot of noise when hitting the limiter and the ecu is picking that up as knock..

if you email me a copy of your current map - in case it has been altered since the copy I have here, I can try and soften up the limiter to try and stop it being detected as knock..
Also logs would be worth a check over if you want to email them over too

You should see the lock of knock on my car after a flat shift lol.

Simon

[Jolly Green Monster]

heres one I prepared earlier

[Jolly Green Monster]

battery issues

[SpecB]

Cheers Simon I'll try to give the car a bit of a decent run and pull the logs from that, currently the logs are all only around town type driving as I've not had a chance to open up on the last few outings!

I'm planning to try and come up soon to get the map looked at properly plus add a sensor pack and possibly Toucan with some limits set, also as I'm barely using the car once a week at most I'd like a bit of a cranking delay to build oil pressure before starting without removing the crank sensor each time!

[Jolly Green Monster]

Might be able to quote you happy on toucan and sensors when ready.

How about a cal position where it wont start, crank it on that until oil pressure and then change cal

[SpecB]

That sounds good to me!

I'll be in touch for a quote, probably looking at next year though due to the imminent arrival of the toys fund Sapper!

[Jolly Green Monster]

Lol

Compared to the car they are cheap