i have been haveing problems sustaining boost with my phase 3.5+
one day its 22psi and the next day it decreases to 17psi, when you turn the nut on the actuator boost does not increase unless you turn the nut around 25 times
i phoned gavin to see if he had experanced this problem before, he suggested that there was a "ring washer" that had cracked in the exhaust manifold, i took the manifold off after checking all of my boost pipes and i cant find any washers inside
there are no cracks on any of the components and everything seems fine.
i dont understand why the actuator increases boost upto a certain level normally (15-17psi only one or two turns of the actuator nut) but anything over that and the nut will not affect boost unless you turn it 25 times or more
You probably already know this but :-
Boost does change from day to day due to temperature and if the cars been running for a while the engine bay will be hot which again will alter boost.
Also, the way to achieve the biggest boost reading is to floor the accelerator from very low revs (1,500/2,000) in 5th or 6th - this will result in a bigger over boost than usual and hold slightly more boost to the redline. In 1st and 2nd and possibly 3rd maximum boost may not be possible to reach. One day it may have been cold and you've dropped the accelerator in 5th from low revs and racked up a high boost figure, the day after it may have been warmer, the engine bay may also have been warmer and you could have been taking readings in low end gears.
Just a thought.
Also, aren't C20LET's 9:1 compression ratio? wouldn't 20Psi be the maximum safe boost (with a front mount intercooler)?
The last of the range Punto GT's were 9:1 and the maximum safe boost was 1.2Bar/17.5Psi or with a front mount intercooler you could run 1.35Bar/20Psi - anything higher would result in major high temperatures in the head etc and would probably melt somthing after a few good hard runs. Doesn't the same rule apply to the C20LET or does that fact that its 2.0l and not 1.4 change a few things?
Originally posted by T.F.S. 105 Posts
Posted - 22/06/2003 : 09:12:13
i phoned gavin to see if he had experanced this problem before, he suggested that there was a "ring washer" that had cracked in the exhaust manifold, i took the manifold off after checking all of my boost pipes and i cant find any washers inside there are no cracks on any of the components and everything seems fine.
Gav might mean the wastegate which the penny valve sits on - it may have cracks which don't have to be that big to bleen away the 5psi you are missing. The fact that it varies one day to the next might be because the exhaust manifold will get hotter after a few runs making the cracks (if there are any) expand.
its not that boost changes from one day to the next, it was ok and then boost decreased one day and has stayed like it since
the penny valve is uncracked and seems to seat well
the nut on the actuator turns, the rod stays static and is held with mulgrips
i have a new uprated actuator from gav and i recently changed the studding/actuator arm, this meant i had to "set up" the wastegate, boost increased normally (turn one or two times, take for car for a run, repeat if nessasary) until 17psi but after that no increase in boost was avalible until you have it wound right up (25 turns later)
my boost switch on the 3.5+ is not working either, i have checked the wires and they are fine, could this be a chip problem?
I have the 3.5 phase kit on my LET. Are you getting the amal valve to TICK! Stage 1 on switch should tick constant. Stage 2,3,4,5 should tick constant, then stop when at full throttle. I had this problem with mine, so i wasnt getting full throttle causing less power it also took a long time to boost up with no overboost sometimes. Check this is ok by putting ignition on and putting foot to the floor. Ticking of the amal valve should stop straight away. If this doesnt adjust the throttle cable at the throttle housing end, then adjust at the pedal side there is a 10mm bolt you can adjust to get idle back.
This sorted my 3.5 kit and the car is more powerful and responsive. I also had a -4 uprated actuator and found it hard to control boost with it. So i have changed it to a new standard actuator with the tension spring. Stage 1 boost is about 6psi and i am sure the spec of the phase 3 / 3.5 kits say stage 1 is about 170 bhp.
Thinking of going for NOS myself after seeing your callyT up the strip.
tfs let me know what happens i have exactly the same problem i can get 1.3 bar of boost approx 17psi and after that i cant increase it turbo is new i have no temp problems as my charge temps stay below 37 degrees c cant see any leaks.
whats the chances of it being a chip related problem as i have checked everything.
when you say the boost is 22 one day and 17 the next does this happen without touching/adjusting the actuator.
my amal valve clicks as it should but i do get 0.9 bar in position 1
i think it may be a software problem so i am going to try someone elses 3.5 ecu thats if there is someone around the westmidlands who has one.
my standard chips also felt qwuicker without a doubt.
My boost switch works!!!!
Stage 1 should tick if not it the amal valve might be sticking. Give it a tap a few times and then see. If not replace it about £40 new.
Stage 2,3,4,5 the ticking should stop as soon as the throttle is fully open, if it does not then all it needs is set up correctly. Try the accelerator cable first as Tabs had this problem as well. Then set the actuator up for the beginning moving step by step.