My zed pops a lot from the exhausts when you accellerate and come off throttle, obviously more so the harder you accellerate / the further up the rev range you go. For example, if you accellerate briskly in third gear up to around 5,000rpm and come off throttle, as the revs come down you generally get 4 or 5 pops from the exhausts. Id say its more prominent now the weather is colder. Personally I was quite happy with it as I was (still am I think) of the opinion that this was fairly normal for a car of this nature and with the spec that it has. But today I took my brother, a NA owner for three years, out for a drive today and he thinks that it shouldnt be doing it as much as it is and that in the long term it may lead to detonation. He thinks that the fueling is wrong. The car has twin blitz filters, de cat, powerflow exhausts, and has a manual under bonnet boost adjuster valve. I was told by previous owner charlie (300horses) that boost was set at 0.8 bar and amoungst the service records a boost upgrade is mentioned but I do not have a aftermarket boost guage installed so cant be sure exactly what boost is being run. All I can say is when you give it full throttlle the factory boost guage takes the whole of the rev range to reach 0.7 bar so id say that its running pretty standard boost.

I'd say your brother is right.

 

sounds too much, and possibly a sign of over fuelling mate

My car is running 14-15psi and pops occasionally but never as much as your car seems do to, my car is also set to run just a little bit rich, maybe yours is putting just a little bit too much unburnt fuel through the exhaust.

 

Also you say it takes the whole of the rev range to reach the max boost setting? That is very wrong, unless your boost gauge is shagged it should reach max boost around 2500-3000rpm.

Popping is a sign of serious over-fuelling...and if your not hitting full boost till the end of your rev range then performance will be suffering quite a bit, you should be hitting full boost on stuck tubs at under 3k rpm.

Just been out for another blast. I am hitting full boost between 3500rpm and 4000rpm according to the guage. If I accellerate in third (full throttle) from 2000rpm im getting about 0.5 bar by between 2500rpm and 3000rpm then 0.6 bar between 3000rpm and 3500rpm and then 0.7 bar between 3500rpm and 4000rpm. If I then keep my foot down till the end of the rev range it maintains 0.7 bar. Without an aftermarket guage I dont no if it goes higher than that. Obviously the fact that 4000rpm to 6500rpm in 3rd gear goes by pretty quickly combined with the fact that im approaching 100mph and running out of road makes it dofficult to say whether it feels like there is an increase in boost after its reached 0.7 bar! The general delivery of the power is smooth. Without driving another zed with the same spec I cant be sure that what is being displayed on the guage is what is actually happening. It does feel a bit laggy when accellarting like I described from 2000rpm in 3rd gear so id say that its likely that the guage is giving an accurate reading of whats actually happening. In which case id say ive got atleast one problem. If its running rich would this contribute to the boost not coming in as it should? Or maybe when the boost upgrade (if there is one) was done maybe it was set up like that? In which case you would think that they would have set up the fueling accordingly? Or are my turbos just coming to the end of there life (I hope not!)?

Just some ideas what are going on in my head: -

 

1. could it be a bad connector or faulty sensor causing delay in full boost?

2. a boost leak?

3. badly set up boost controller valve?

4. an exhaust blow confusing the ecu?

5. is it going into "safety boost mode" because of the overfuelling?

 

I am not an expert but I know from reading posts on here that a lot of you know pretty much everything there is to know about zeds. I can try and have a look at these tommorow I just want your opinions on my thoughts and / or your suggestions.

Only thing I have seen that has caused a delay in boost like this is a weak spring in the wastegate actuator, was opening very early so boost was taking much longer to build up.

 

Strange problem tho so could be many things.

first things to check:

-boostleak

-coils and/or coil connectors

-plugs (make sure plug gap is set to approx. 0.9-0.8mm)

-diagnose o2 sensor(s)

 

a PTU on it's way out could also be causing this...only way to check this is to swap it with a known good one.

 

-Eric