Siemens Deka 60lb Injectors Group Buy Mkii - Injector Bonanza (26 set's AND CLIMBING......)

[groper]

[quote name='Headsex' post='539710' date='Jun 2 2007, 09:54 AM']Done it last night..
Oh and its not a cbf tune scribr.. I spent some time on it lastime. Changing the injectors is a easy reprogram with more boost added. After a while you can guess roughtly what duty cycle to add to get you to certain boost. He needs valve springs and actuator. But more importantly the wastegate done as it overboosts, the boost stays around 12psi top end on a night like last night regardless of duty cycle. During the day its controllable..[/quote]

whats the deal with the wastegate? i understand that supposedly it doesnt flow enough gas to keep the turbine speed down at high power levels, but C & V say they dont need to do it, all they do is fit an 8psi spring... im referring to the orange car that they put the process west plenum on... i dont understand why they dont need to do it, can you explain it for me?

[ENVY-T]

Go in a car with it done, and then one without, it is so much smoother when it's flowing right.

[Headsex]

[quote name='groper' post='539769' date='Jun 2 2007, 02:19 PM']whats the deal with the wastegate? i understand that supposedly it doesnt flow enough gas to keep the turbine speed down at high power levels, but C & V say they dont need to do it, all they do is fit an 8psi spring... im referring to the orange car that they put the process west plenum on... i dont understand why they dont need to do it, can you explain it for me?[/quote]

To make power you need air and fuel and ignition.. The more air and fuel into the cylinder, the bigger bang, the more power, and of course the more exhaust gas. So more power is more exhaust gas.

Problem is, the wastegate port is not big enough. During the day envy's car holds boost fine with approx 12psi topend. Remeber he has no valve springs.. At night, the airs colder and more dense, so that resulting with more fuel (computer compensates based on air temp) results in bigger bang. With a intercooler and a good flowing exhaust the engine produces more exhaust gasses which the standard wastegate cannot bypass hense pushing the boost up.. On standard injectors, this is like 12psi top end... afr's are in the 13's.. Bad. Injectors made his car safe.

But if you had a restrictive exhaust on the car, it would pose backpresure on the gases after the turbo and encourage more gases to bypass out the wastegate keeping boost down.

Envy has the standard 3psi actuator on his car.. So according to c&v's comments, does he goto a 1.5psi actuator?? No.

On my car, I have a 12psi actuator. When I put my nizpro stg2 kit on, at night immediatly it overboosted to like 18psi.. That's even with the actuator connected directly to turbo bypassing the boost control. Mind you I had alread modified my wastegate port.. Lession 1, I didn't modify it enough. So I took the turbo off again, opened it up and also setup the flow to encourage more exhaust gas flow to the port. Put it back on, and presto, no more overboost. A 8psi actuator would not have helped my problem. A quick fix was to put a restrictive cat into place.

So before you think gutting the cat is cool, thing again, it will give you overboost issues, and your tuner nightmares.. Lol

[Fat-Tony]

Also when the actuator vac line is connected directly to the wastegate actuator, thus bypassing the PCM's control over the wastegate opening and closing you will only ever see 12psi with a 12psi spring actuator and 8psi with an 8psi spring actuator. Now if the car is still overboosting with the line connected directly to the wastegate it leads you to one of 2 possible causes to the problem. The wastegate port is not big enough to support the gases flowing that the engine can output due to the freer flowing intake and/or less back pressure posed by the exhaust, or the wastegate has been wound up to tight when fitting. This increases spring tension due to the shorter spring length. When the wastegate port is sufficient enough to flow the gases outputted by the engine and the car is still overboosting, then you will find that the actuator has been wound up to tight, which will cause it to hold shut longer and the turbo will build a higher boost pressure than the spring is rated to, leaving you scratching your head as to why a car might be running 5psi more pressure than the actuator is rated at. Edited 02/06/07 04:10 PM by Fat-Tony

[ENVY-T]

[quote name='Fat-Tony' post='540010' date='Jun 3 2007, 01:57 AM']Also when the actuator vac line is connected directly to the wastegate actuator, thus bypassing the PCM's control over the wastegate opening and closing you will only ever see 12psi with a 12psi spring actuator and 8psi with an 8psi spring actuator. Now if the car is still overboosting with the line connected directly to the wastegate it leads you to one of 2 possible causes to the problem. The wastegate port is not big enough to support the gases flowing that the engine can output due to the freer flowing intake and/or less back pressure posed by the exhaust, or the wastegate has been wound up to tight when fitting. This increases spring tension due to the shorter spring length. When the wastegate port is sufficient enough to flow the gases outputted by the engine and the car is still overboosting, then you will find that the actuator has been wound up to tight, which will cause it to hold shut longer and the turbo will build a higher boost pressure than the spring is rated to, leaving you scratching your head as to why a car might be running 5psi more pressure than the actuator is rated at.[/quote]


What would you know!!!

[Fat-Tony]

I don't know how to break up a post into paragraphs

[groper]

yep i understand all that, but what i dont understand is why C&V`s car is not over boosting beyond 16psi without the wastegate done... and its running 370rwkw (measured thru an auto) with boost spike up to 16psi then tapers back down to 13psi at 6000ish rpm with just 8psi spring... which i think is pretty much fine... why doesnt it go all the way up and over 20psi which youd think it would with that much power???

the dyno graph is posted in process west section if you havnt seen it...

[Fat-Tony]

Groper we couldn't make an accurate determination without actually knowing the desired boost settings and wastegate duty cycle. Though as I am awaiting production and delivery of my kit, I will find out how it all comes together soon enough. Edited 03/06/07 02:01 AM by Fat-Tony

[Headsex]

[quote name='groper' post='540071' date='Jun 3 2007, 11:33 AM']yep i understand all that, but what i dont understand is why C&V`s car is not over boosting beyond 16psi without the wastegate done... and its running 370rwkw (measured thru an auto) with boost spike up to 16psi then tapers back down to 13psi at 6000ish rpm with just 8psi spring... which i think is pretty much fine... why doesnt it go all the way up and over 20psi which youd think it would with that much power???

the dyno graph is posted in process west section if you havnt seen it...[/quote]

Chances are this car still has a cat in the exhaust, so the overboost would not have been so great.. it IS possible to tune a car even though boost in uncontrolled via overboostung (thats what envy-t's is doing at the moment), but really depending how good everything before and after the engine is flowing determines how much it overboosts..

[ENVY-T]

Danny, you better get the dremel out on that spare front cover! I want zee ported wastegate and will get an actuator!

Thanks for all the trouble too, car goes like stink now. And my fuel economy has not been better. Who woulda thought seimans would give me such good economy.