XYZ Donating Members 1,171 Member For: 15y 4m 17d Posted 21/12/11 11:04 PM Share Posted 21/12/11 11:04 PM Can someone explain to me the need for these over boost valves if your car is tuned correctly? I understand putting these in as a precaution and as a safe insurance, however I have also heard people using these for boost control instead of wastegates? Sounds like a bandaid fix for bigger problems? Link to comment Share on other sites More sharing options...
IH8TOADS Silver Donating Members 3,618 Member For: 19y 6m 26d Gender: Male Location: OZ Posted 21/12/11 11:17 PM Share Posted 21/12/11 11:17 PM Most cars are tuned in open loop boost control at close to 1:1 ratio. So in 4the gear and close to the 1:1 ratio the tuned will set boost perfectly. In reality though you will see less boost in lower gears and higher boost in high gears. The overboost valve can be an advantage in higher gears and also for ZF's with spiking gear changes. It has to be set correctly though. You can build in some nifty protection to the factory ecu. 1 Link to comment Share on other sites More sharing options...
RIP_HSV HOON Member 1,636 Member For: 14y 10m 19d Gender: Male Location: W.A Posted 21/12/11 11:26 PM Share Posted 21/12/11 11:26 PM Can someone explain to me the need for these over boost valves if your car is tuned correctly? I understand putting these in as a precaution and as a safe insurance, however I have also heard people using these for boost control instead of wastegates? Sounds like a bandaid fix for bigger problems? that's why a mate had to have two fitted, due to the way a workshop fitted the external gate it was boost spiking and couldn't afford to mod the turbo at the time so simon fitted a second valve to try to get more boost out of it lol Link to comment Share on other sites More sharing options...
djqc Member 291 Member For: 13y 3m 25d Posted 22/12/11 12:01 AM Author Share Posted 22/12/11 12:01 AM They are very easy to set-up yourself on the street if you know how to datalog. I've come across fitted ones that are set to high though....infact the one in question was taken to another tuner who advised the guy that it was being used to control boost as opposed to the wastegate duty cycle table.....which I proved to be bu11sh1t. XF is that 370kw on a stock sized turbo and pump fuel? If so its hardly conservative to pull those numbers on 14psi.Good to hear the car is sorted, would be pretty perky with 21psi! I'm keen to take you for a spin and see what your datalogging says about it all Link to comment Share on other sites More sharing options...
XF Falcon <put funny sh*t here> Member 3,365 Member For: 18y 2m 25d Gender: Male Location: Perth, NOR Posted 22/12/11 03:53 PM Share Posted 22/12/11 03:53 PM XF is that 370kw on a stock sized turbo and pump fuel? If so its hardly conservative to pull those numbers on 14psi.Stock turbo with ETM external wastegate and 98 fuel (4" dump, 5" cat and 4" exhaust, Siemen Dekas, Walbro fuel pump, full Plazmaman 1000HP kit).It doesn't come on boost as hard as other cars I've seen, and only makes about 700Nm as a result - most similar powered cars I've seen push closer to 1000Nm which I've always assumed is because the power is coming on harder and faster? Link to comment Share on other sites More sharing options...
IH8TOADS Silver Donating Members 3,618 Member For: 19y 6m 26d Gender: Male Location: OZ Posted 22/12/11 10:56 PM Share Posted 22/12/11 10:56 PM You 'generally' need a heap of timing, and run the engine very close to the boarderline knock threshold to make that power on that boost....I question the very conservative part. Just putting it out there lol. Still the nicest XR I've seen around. Link to comment Share on other sites More sharing options...
Roof Member 213 Member For: 16y 4m 30d Gender: Male Location: Perth | Busselton Posted 22/12/11 11:06 PM Share Posted 22/12/11 11:06 PM 21psi is a fair whack for stock internals!!Did you have the stock BOV still hooked up? Link to comment Share on other sites More sharing options...
djqc Member 291 Member For: 13y 3m 25d Posted 22/12/11 11:32 PM Author Share Posted 22/12/11 11:32 PM Na. I don't think the bov is hooked up. The reason I say this is because there was a boost leak where they blocked the bov so I'm assuming that it isn't hooked up. And that would explain the insane flutter that I'm getting Link to comment Share on other sites More sharing options...
234Fpv Donating Members 522 Member For: 13y 6m 26d Gender: Male Location: Yeppoon qld Posted 24/12/11 08:18 PM Share Posted 24/12/11 08:18 PM I can imagine the flutter on 21psi. I pulled my bov off to see what it was like at 19psi and it was mental. Being a manual it was a bit much so I hooked it back up.Sent from my HTC Desire using Tapatalk Link to comment Share on other sites More sharing options...
djqc Member 291 Member For: 13y 3m 25d Posted 25/12/11 06:16 AM Author Share Posted 25/12/11 06:16 AM Just got a fault code saying random misfire and the car ran rough for a few minutes. Then when I looked in the sct box, it had a few other misfires in cylinder 1. Anything to be worried about? Link to comment Share on other sites More sharing options...
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