more troubles now hesitating and backfiring- added aem graph
Turbo Mini Forums

hi all as a few of you know ive had many problems with my engines etc well i had the car rolling road tested and set up fueling was spot on last week. now i have done 400 miles since it seems to be intermittent from day to day i personally think its the dizzy module.

so it hesitates and backfires through the carb/air filter at 4500rpm when on full boost 1bar, i have refilled the dash pot with 20 50 the carb its self is new, lean of pipe is good etc it seems to start juddering first also mainly does it in 4th ive had it do it in 3rd once but im sure the fueling is good as i havent changed a thing since the rr. so its load based, im running bmw cooper s plugs and there all fine.

does any body agree ? as its intermittent it make me think its electrical and when it does it it doesnt want to rev to much more than 5 atall in 3rd


i am also running the teepiece trick and a stronger spring in the dashpot
thanks charlie

Edited by charlieb150 on 4th Apr, 2013.

Do you have an AFR gauge?

In the 13's at last!.. Just

no :/ i need to get one dont i then that will tell me whats going on

try closing up the plug gaps to .5mm

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

even though there the cooper s ones with the 4 electrodes

Spark will only jump to one electrode. Id bin those and put seem decent normal plugs in, and close the gap as per Roberts suggestion. With a standard dizzy etc you may need a smaller gap when on boost.

Why BMW Cooper S plugs? What heat range are they?

well at the time i couldnt get any other plugs than the std 6s anywhere so i thought id grab some from bmw next door to my work as there under the same kinda abuse as these engines there( r6 ) on the plug

what plug numbers would you recomend

NGK BPR7ES will be fine at 1 bar.

WWW.TURBO-MINI.COM

if all the ignition side checks out ? any misfires under boost will be cause by a lean mixture under boost,

you need AEM lambda to see where you are pronto! before any damage is done to the engine, once you sort that and the problems still maybe there you need to look at mechanical parts ? valve etc guides nipping ?

hope this helps .....keep us posted

Thanks guys ill Chuck some bpr7es plugs in with a. 5 gap and will order one on Thursday ,ive seen one with boost aswell in the centre is it worth it for 202 quid aem one

That's up to you Charlie , IMO I would just purchace the single gauge if you have a good boost gauge already ? But if you have loads of assets. Go for it.

BKR6EQUP is BMW mini cooper S

BKR7EQUP is BMW mini cooper JCW's

BKR7EIX Iridium tip & BKR8EIX Iridium tip these's are colder plugs and used when more boost is added

all of the above R53 plugs

Edited by Chalkie on 27th Mar, 2013.

Stupid question then,
Does everyone use bini sparkplugs when upping boost?
Got some good NGK mini ones?

Reading up on RTS Clutches

Benross do you have the 160 one its just i have nowhere to put it where as if i get theone with boost i can loose th boost gauge car was perfect thismorning on the way to work so will get agauge and see what it says

Edited by charlieb150 on 27th Mar, 2013.

I don't know anybody that uses bini plugs specifically.

generally just choose a colder plug. So an NGK BPR6 is hotter than a BPR8. The BPR8ES has a shrouded electrode and was used in the old RS turbo. You need to get the plugs right for the application. and there are lots of opinions out there about what is best. You cant really gain power from plugs, only lose it.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

get an aem on there asap, i have only ever experience pop back through the carbs with a lean mix, not saying it is lean just dot go driving on boost untill its sorted

and im on NGK BPR6ES here been fine well over 1 bar boost and dare i say it nearly 2 bar and there sill in one peice

Yes i moved to the darkside

Instagram @jdm_brett

Thank brett ill order one tomorow and i m going to wind the boost right down to 10-8psi for wheels day and drive it carfully thanks

just orderd this http://www.ebay.co.uk/itm/300733137728?_trksid=p5197.c0.m619

Looks like a useful bit of kit if a bit expensive.

Yeah but I thought for the sake of 40quid i can data log boost afr and rpm rather thanjust afr

hi all i brought the aem fail safe gauge and it doesent seem to go past 12.5-1 on full boost is that far out

You should be looking for around 12 to 12.5-1 on boost.

WWW.TURBO-MINI.COM

thanks phil it is alot richer lower down just when it comes on boost at first 10.5-1 and 15-1 at idle up to 3000rpm