IH8TOADS Silver Donating Members 3,618 Member For: 19y 6m 16d Gender: Male Location: OZ Posted 05/12/11 02:41 AM Share Posted 05/12/11 02:41 AM Air pressure from the compressor wheel flows through the wastegate solenoid (controlled by the PCM) and then to the nipple of the wastegate actuator which acts in a diaphram and pushes the actuator rod out to open the wastegate flapper. The PCM controls te solenoid cycle time, so 100% means no air applied to the actuator rod and 0% means full boost pressure applied to the rod and the gate will open wide.The actuator spring tension needs to be sufficient enough to ensure the gate stays closed at 100% duty cycle.....if not boost will be bled off. If the actuator spring tension is too high then boost pressure will not be sufficient enough to open the gate and hence boost pressure above desired will be experienced. The PCM can be used to control boost in both closed loop and open loop....but that's another tutorial. The fact that the boost graph isn't flat probably means insufficient actuator tension for the desired boost pressure. If you log duty cycle and see that it's high, this will prove the point! Link to comment Share on other sites More sharing options...
wa g6et Member 657 Member For: 13y 7m 21d Gender: Male Location: Perth NOR Posted 05/12/11 03:07 AM Share Posted 05/12/11 03:07 AM So what is the consequences say between using a 8lb actuator compared to a 12lb. It probably depends on power and boost you are after and I assume.Tuners have different opinions on this. Mine says for my requirements, FG std turbo and 300rwkw, the 8lb was what he uses and controls the boost better with the PCM, not really sure what this means though, was kind of hoping for a better explaination of this. Is it then diificult to control boost under 12psi if using a 12lb actuator. I have a low boost tune in my SCT tuner for use with 95ron would this still be possible with the 12lb actuator.Does this mean for 400rwkw with the bigger turbo 8lb wouldn't be enough, and 12 or higher would be needed.Sorry Luke if this is bit off your thread but thought some technical infromation for us novices might help understand what goes on. Link to comment Share on other sites More sharing options...
IH8TOADS Silver Donating Members 3,618 Member For: 19y 6m 16d Gender: Male Location: OZ Posted 05/12/11 04:03 AM Share Posted 05/12/11 04:03 AM (edited) If you have an 8psi actuator then 8psi is generally the lowest boost you can run. Depending Inge set up 8psi actuators are perfect for 11 to say 15 psi applications. 15psi to 17psi I would use a 12psi actuator and above 17psi I would go a 14psi actuator. Quality of the port job, exhaust backpressure and whether you an bleed air to the top of the gate in an external application all affect the ideal actuator / gate spring tension.Edit yeah, 8lb is too weak when you're trying to push decent boost with a turbine housing that has decent backpressure.....such as the one in question. Edited 05/12/11 04:08 AM by IH8TOADS Link to comment Share on other sites More sharing options...
wa g6et Member 657 Member For: 13y 7m 21d Gender: Male Location: Perth NOR Posted 05/12/11 06:05 AM Share Posted 05/12/11 06:05 AM Thanks heaps, makes better sense now. The turbo size/ back pressure starts to come into play with the actuator size when you up the anti.I really appreciate you helping shead a bit of light on this issue. Not always easy with mine being my first turbo. Starting to get a better handle on these cars now.Pretty sure Luke there is an answer to your issue amoungst all this. Lots of people who really want to help you get what you want from your car. Link to comment Share on other sites More sharing options...
ALF05T Member 453 Member For: 18y 9d Gender: Male Location: Sydney Posted 05/12/11 07:15 AM Share Posted 05/12/11 07:15 AM WA G6ET those wheels look awesome do they come in 19x8.5 19x10's?My axis hiros are too big for the rear at 10.5" lookin for some new wheels Link to comment Share on other sites More sharing options...
wa g6et Member 657 Member For: 13y 7m 21d Gender: Male Location: Perth NOR Posted 05/12/11 09:07 AM Share Posted 05/12/11 09:07 AM WA G6ET those wheels look awesome do they come in 19x8.5 19x10's?My axis hiros are too big for the rear at 10.5" lookin for some new wheelsJust in 19x8 as per original FPV GT 5th Anniversary or GT-E/F6E Link to comment Share on other sites More sharing options...
Vevapower Waiting for the 1st N/A 12! Donating Members 2,533 Member For: 16y 11m 13d Gender: Male Location: Sydney Posted 05/12/11 09:33 AM Share Posted 05/12/11 09:33 AM Was your 425 tune on E85 or pump?Either way great power, how much extra did you make on E85?How much is E85?425 tune was on 98 but ran up on a DD Dyno!E85 is where I get it Caltex is anywhere from 1.10 - 1.20 per litre!Made about 50 rwkws on E85 Link to comment Share on other sites More sharing options...
ALF05T Member 453 Member For: 18y 9d Gender: Male Location: Sydney Posted 05/12/11 08:54 PM Share Posted 05/12/11 08:54 PM Wholey Farrrrk. 475rwkw on E85 that is some good power Link to comment Share on other sites More sharing options...
CHLAXN Donating Members 932 Member For: 16y 8m 2d Gender: Male Location: north QLD Posted 06/12/11 11:07 AM Share Posted 06/12/11 11:07 AM Hey vevapower what size rims you got ate they 19's? Also what tyres you running with all your power? Also a Bummer about the input shaft mate. Link to comment Share on other sites More sharing options...
Boosted1 Member 346 Member For: 16y 2m Posted 07/12/11 12:46 AM Share Posted 07/12/11 12:46 AM (edited) here is my dyno sheet. showing its coming on full boost round 3500rpmnot bad power for 16-17psiwe are working on it coming on earlier. Edited 07/12/11 12:49 AM by Boosted1 Link to comment Share on other sites More sharing options...
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