Having some trouble with the cossie at the mo and need some advice if anyone can help,

Right the prob is when the bastard reaches around 15psi/ 1bar it hits a brick wall, you can hear wot sounds like wastegate chatter, can i also add it dosent always do it just about 90% of the time, sometimes it will pull right up to 26 psi and will fly like a rocket then you change gear and it will hit the brick wall again sending you nearly into the screen lol,

List of parts ive changed are 3 bar map, act sensor, actuator, and its just had a chip from MSD , spark plugs.

Helppp please as its really starting to bug me now

Many thanks,

Steve.

 

if you don't put your foot down so hard the problem will go away

Sorry Steve, no idea

Mines going ok though

Steve.

 

throttle position dont seem to matter as soon as it hits 1 bar it does it,

just wait for your diff to go again

Steve.

 

Bitch

Steve.

 

sorry m8 couldnt resist it,

hows Simons new motor going,

Steve.

 

What is the engine's rpm when this happens?

 

havent really studied that m8 but i would say around 4k rpm

Steve.

 

Have you tried the plug gaps ?

Steve.

 

yep gapped them as per instructions from MSD.

steve.

 

you say it makes a noise like waste gate chatter! sounds to me like for some reason you are getting compressor surge, i.e the turbo is producing more air than the engine can consume, although i dont understand why it would do this intermitantly.

 

how about fuel filter ... very overlooked point on a cosworth

 

so how do you combat surge then m8.

Steve.

 

not changed that yet Eagle but its on my hit list.

Steve

 

well a few questions first, when did it start doing it? did you change something or do a conversion, also what turbo have you got?

 

i had the same sort of feling .. would boost up and then felt like it hit a revlimiter and would go no further.. also sounded like it was struggling for boost..
removed filter and the airline was only just blowing through it.. how fuel was getting through was the real worry
now i change it every year only a few quid but not nice if you run low on fueling at top speed

 

the engine came from my moonstone saph then into the magenta one, all was fine with the engine which ran a T34 with .48 rear housing untill i put a t34 with a .63 rear housing on.

Steve

 

id look here first as well.you never know it could be the easy cheap thing.but usually its not.

 

actuator?

 

as above m8 just had brand new one from MSD so that should be ok,

It deffo does it at 4k as ive just been out in it, any gear any speed,

Steve

 

oops didnt see that. my bad.

also, was it doing this before or after your chip? It could just be the ECU cutting the power because it thinks theres something wrong.

 

did it with the other chip in the ecu, also have changed ecu also.

Steve.

 

to me given the info I have at hand it sounds like you changed from a .48 to a .63 housing and then the problem appeared, the problem as you describe it sounds like your getting surge, I would go with for some reason that is the case but I dont know why it would surge at such low boost, I may be talking bollocks but is there any restriction in your inlet system? are you getting full throttle etc, it seems that something must be stopping your engine consuming all the air that the turbo is trying to give it at 4000rpm, most odd. Obviously try the fuel filter etc just incase, also have you tried asking someone like Stu who supplied your chip if he has any ideas why it might be doing this? he obviously has a wealth of knowlage on the subject of tuning cossies and may have come across this one before.

 

dont know of any restriction m8 if anything i think the head has a slight bit of porting to it, the secs monitor is saying 100% throttle when i nail it, going to ring Stu in the morning just to see if he can shed some light on it, just cant see why it sometimes dont do it.......crazy.

Steve.

 

48 housings are know to surge but would have thought it was before 4k..

does it matter what gear you are in? does it surge in higher or lower gears?

 

does it in all gears Euan, no matter wot speed as soon as you get to 4k it dont go any further

Steve

 

are all your air intake pipes solid ie "dont squash compress"

my old rs2 used to die at 3000 revs ..as you say car just died

problem was old air intake pipe was soft and fooked ..

may be worth a try

 

most are newish samco allthough the one that goes from the turbo to intercooler does feel soft, its still the same age as the rest mind.

Steve.

 

you might want to check out the grounding on the ECU..
to make sure connect the grounding directly to the ECU..
pin 1 and the other one i forgot which one it is... maybe someone else here can tell you.. i thought 19 or something.. check first please

Seen this before and that was the problem..

good luck !

 

i had a similar prob with my 200sx turned out it was the afr meter (dunno if it could be the same for yourself but worth a try!!