I had a quick question to ask people as I'm a little confused... Stock the TT runs quite rich which is just fine with me as I'm looking to increase my boost past stock soon. I run datascan to log and chart my car quite a bit and rather than taking it to a dyno to check the mixture after/during turning up the boost I was wondering how accurate relying on your built in sensors is? Below is a chart I made of me at 100% throttle with RPM vs O2 levels. Now 100 is very rich and 1 is very lean on the O2 sensor, normal driving conditions has this going rich/lean/rich/lean etc.. every second or 2, except when I floor it as you can see it just hits rich and stays there until I back off and then goes back to usual lean/rich etc.. What's peoples thoughts on this? If I turned up the boost to a level where it was say keeping at least 60 or so under full load, would that be safe?
You will be ok... Basically the zed runs rich, and under WOT you would rather be rich then lean or kaboom! Dont rely on o2's as they need replacing from time to time. Just get some 1.1mm boost jets(welding tips) and install them as the tech article, its really an easy job and it will be safe for the zed. Max:thumbsup:
hmmn... Anyone else here running just intake, exhaust and boost jets? What sort of gain would 1.1mm jets give you and is this a frowned upon practice? Say if they gave you 12PSI, would this be enough to run the car lean?
I think 12.5psi is a safe limit for the zed... using the standard ECU, i had my car dynoed with intake, exhaust, UDP and jets and the A/F ratio was perfect. Max:thumbsup: Edit: 1.1mm will give ~12.5psi
That sounds saa-weet! :thumbsup: What sort of rwkw would 12.5psi equate to? (In an ideal world of everything running smoothly)
likewise here my intended mods like runs as follows (roughly in my intended order Brazilian & new wing (ok so it won't make it faster... Bigger sidemounts Boost controller - eventually EBC Chipped ECU (Hitec or the like i guess) Coilovers Much later down the track... Dumps, Manifolds, bodykit but for now i'm looking for a bit more power for little dosh I've got a K&N Pod & a Cat back exhaust Can i safely throw a manual boost controller in and run 12.5 psi with standard coolers & ecu? - how much extra power should this net me? I've also got a busted cat i need to replace... how much gain would i get by replacing both cats with hi-flows? Also, i've had knock sensor issues so it's currently bypassed, considering sticking a new one on the back of the block... how reliable should this be?
If your cooling and fuel systems are working well, and your timeing is set correctly 15deg ( i know some up the timeing) you will have no problems @12.5psi. 1.2 mm jets will give you 14psi, which many people here run seemingly without a problem. 12psi is safer imo. You'll have to get a before and after dyno run to see all this new power, maby 30-40 kw's @12psi, roughly speaking!
stock o2 sensors are narrow band sensors, which means that they only report if the mix is rich OR lean. so over 50 only means that the mix is richer than stoichiometric. likewise, under 50 only means that the mix is leaner than stoichiometric. so turning up the boost till it hits 60 won't mean anything, as 60 simply means rich, but gives no indication of degree of richness. what you require is a wide band o2 sensor, which will report the actual air:fuel ratio of the exhaust gas. then you can wind up the boost, and your wideband will tell you your air:fuel, and you can keep turning up till its like 12:1 or something.
remembering that unless you have a dyno you're doing this with one hand on the wheel and half an eye on the road at speeds rapidly approaching 200kmph under full boost
You may realise a few extra ponies @ 17deg, you may also get detonation, especially if your AFR is not what it should be,14.7.1. More on wide band 02's.http://cherrypicker.tripod.com/id12.html
