Reducing lag

ryan_s3

Full Member
Mar 27, 2004
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not knocking your turbo kit mate! Just interested.So what is the difference between yours and the largest turbo?
 
Dec 31, 2005
1,856
0
London
Mine keeps coming back with missfire codes on cylinder 4, coilpack changed and spark plug checked, but its also coming back with 17964 - Charge Pressure Control: Negative Deviation

Its not going into limp mode but im thinking a boost leak somewhere could be causing the missfires, it does run a bit lumpy on idle and crawling in 1st (in traffic) it judders a lot.

Cant see anything obvious, last time i had a boost leak it turned out to be the intercooler (on my old cupra) which was fine as it was only a laguna jobbie but this pro alloy one would be a lot more expensive to replace so im praying its not that!!

what code would be thrown for the SAI as i know i still need a resistor for that, but i wouldnt have thought it would bring up a missfire?
 

ibizacupra

Jack-RIP my little Friend
Jul 25, 2001
31,333
19
glos.uk
apexi controlling yours, me7 thinks its controlling.. so deviation could be a setting conflict between them
yours cant go into limp mode (actuator pressure limp mode) as your apexi is controlling.

does yours have wideband gauge in there? if so whats it reading when its lumpy etc?
 
Dec 31, 2005
1,856
0
London
dont know off the top of my head, will try and look

im in the area at the moment bill so if i get time i'll give you a bell and pop round
 
Dec 31, 2005
1,856
0
London
i cant sit around.... get bored to tears.
even when sat @ home like now, i'm on the net surfing all things car/engine/turbo/dyno related. sad git syndrome i know

lol not at all, i think its quite good if you get paid to do something you enjoy and research is all part of it.

I could pop down tonight but i was thinking best when i can leave it with you for a couple hours to set up apexi and do some logs etc
 

ibizacupra

Jack-RIP my little Friend
Jul 25, 2001
31,333
19
glos.uk
i am back there mon/tue/weds so drop by and bell me to confirm.. i'm in and out tomorrow, bringing in tonys project car into the w'shop (1.8t ford pop, rear wheel drive) so will be in and out during the morning
 

ibizacupra

Jack-RIP my little Friend
Jul 25, 2001
31,333
19
glos.uk
hows that project going bill?

not much at all for some time. tony got a mk2 escort and built that into a trials car, which he took home from the workshop yesterday so project pops back on again, in bigger more tooled up facilities now. tony was kind enough to lend me his garage for my ibiza's build for 9 months, its the least i can do. between us, building and fabrication of pretty much anything is possible. chassis to build up for the pop is next. i will sort the engine/electrics (dta) and chassis build in the main will be tony working his magic

my old fp greens being used on the ibiza cupra motor sat in it. (some rods and pistons to go in yet to make sure it does'nt explode), but g'box will be interesting to see how it copes with so much more power going thru it than it was designed for. Ford type 9 g'box
 

ryan_s3

Full Member
Mar 27, 2004
1,270
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I've known the bosch sensor used on many dyno's reading around .5 to1 afr richer than a lab spec NTK.
Be careful.
 

ibizacupra

Jack-RIP my little Friend
Jul 25, 2001
31,333
19
glos.uk
I've known the bosch sensor used on many dyno's reading around .5 to1 afr richer than a lab spec NTK.
Be careful.

trouble with ones used on dyno's is they cant get to temperature properly to be accurate, as their internal heaters cant hold them as accurately as they would sit in the exhaust, whcih accounts for some in-car wideband vs external up the exhuast pipe wideband different readings. i stick with the bosch wideband on my zeitronix as its in the hot end of things and does correlate with a "hot" tailpipe one when on the dyno.

having to remove an LS1 sensor tho to calibrate is intolerable to me for an in car fitted gauge. one main reason i dont consider them for my own use.
 
Dec 31, 2005
1,856
0
London
Just to update the thread..

Took it round to bill and coilpack changed, nope, swapped for a new spark plug and within 5 mins it was black, all injector seals checked and swapped around but nope.
cylinders 1,2 + 3 all have a noticeable tone when unplugged but 4 makes no difference??

It doesnt missfire like an obvious coilpack gone, but brings a fault code up every so often on cylinder 4 and idles lumpy, as well as the negative deviation code, but it boosts as it should, seeing 14.9 - 15.2 on the wideband guage on idle and 12's under load.

I was stuck in traffic on the m25 (for 3 hours!) and it was really annoying as I had to ride the clutch the whole time as it would judder in 1st, (you know where you're crawling in traffic and you manage to let the clutch all the way out but dont need to accelerate) bill raised the idle rpm by 100 which has smoothed out the rough idle a bit but its still there.

So.... its going to total-vag for a compression test, if that comes back ok then it might point to a wiring fault.
 
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