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Discussion Starter · #1 ·
ok well i just got my 08 evo x gsr a little over a month ago, the car has always ben spiking 24-25psi and settling at around 17psi...and the car is completly stock except for a green drop in filter and a clutch. but one night the hose that conects to the bov came off under full boost and the service engine soon light came on. i pulled over fixed the hose and took the negative cable off the batter to clear the code. after that incident the car was only spiking 22psi and settling at 15 wich from what i read is normal. but a few days ago i did a brake fluid flush at work and now its hitting 24-25psi again and holding 17 :wtfsign:is that safe for a stock car?? the only thing i can think of is the boost controll soliniods are right by the master cylinder. any input would help i realy dont whant to damage a car i just got...
 

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my 100% OE GSR will hit 23psi and taper to 16-17psi.
 

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Discussion Starter · #3 ·
Thank you it just droped down to those numbers today idk why it was hitting 25 but its realy hard to find good psi information about this car ive seen anywere from 13.5-17 being normal and was unsure whats true
 

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My question is, how has the temperature varied? Are you sure these differences in boost pressure are not related to temperature or some other external variance? Also, when you fixed the hose that popped off, are you sure it was still not leaking boost? Have you retightened the couplers on anything boost related recently?
 

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Thank you it just droped down to those numbers today idk why it was hitting 25 but its realy hard to find good psi information about this car ive seen anywere from 13.5-17 being normal and was unsure whats true
Incorrect, 21-23 psi peak is pretty normal for a stock tune, 23 being on the high side and 21 being typical. At 7k rpms it's typical for the boost to taper to around 15-16 psi on stock tune also.
 

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Discussion Starter · #6 ·
No no changes to any couplers and it dosnt matter what tempatures it would do it on hot or cold days. I unplugged the boost controll solinoids and cleaned them out i found they were moist inside the connector i assume from brake fluid and i made a few pulls and it still spiked high but after maybee another hour it just stoped and dropped to a normal level. But that still dosnt explain why the car was spiking 24-25 when i first got it. And why it would stop and boost normal after the bov hose came off. Unless the jolt from suddently loosing boost shook something loose?
 

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Discussion Starter · #7 · (Edited)
This morning on my way to work 4th gear spike 22-23 and held about17
But third gear spiked 24-25 and held about 17 the ahorter gears seem to be getting higher spikes sometimes. And yes i have gotten 25psi spikes in first gear. And all of the boost pills are in place
 

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Do you have any way to log your boost via a tactrix cable or AP? Maybe your boost gauge is off.
 

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Discussion Starter · #10 ·
Im pretty sure its the stock tune for 2 weeks it was running 22psi spikes with 15psi at redline the car did have an ets intake when i got it tho. And no i have no way of data logging or monitoring anything. The boost gauge is accurate i belive since the vac is reading around 20ish at idle and 18-19 vac when a/c compressor cycles on.
Is ther a way to make sure its the stock tune?
 

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This morning on my way to work 4th gear spike 22-23 and held about17
But third gear spiked 24-25 and held about 17 the ahorter gears seem to be getting higher spikes sometimes. And yes i have gotten 25psi spikes in first gear. And all of the boost pills are in place
The next question is, when you are getting these spikes, at what RPM are you going WOT? At like a very low RPM? Are all your tests the *same* in terms of when you go WOT. I have a theory, but I need you to go WOT in 3rd gear at like 2k RPMS and tell me what PSI you hit, then go WOT at like 3000 and tell me what PSI you hit and then 3500 RPMS and then 4k rpms.
 

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Discussion Starter · #12 ·
The lower rpms like 2-3 it will useally have a mellow spike but in the3.5-4 range the spikes are higher but i have had instances were it still got high spikes from a 3k wot. And i have checked the exhaust bolts have not ben tamperd with cuz i was thinking maybee the cat had ben gutted but its intact
 

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The lower rpms like 2-3 it will useally have a mellow spike but in the3.5-4 range the spikes are higher but i have had instances were it still got high spikes from a 3k wot. And i have checked the exhaust bolts have not ben tamperd with cuz i was thinking maybee the cat had ben gutted but its intact
Ok so this is a combination of 2 things I think. First that when you got WOT at higher RPMS where the turbo spools almost instantly, it's common to get an overboost spike because your car spools so fast that the wastegate cannot react fast enough. I fought with this quite a bit on my car and ended up fixing it by using minor upward boost correction, a lower WGDC than my target, and gear based boost control. Between the 3 I was able to eliminate this brief overboost spike. The stock tune though, doesn't have those changes, so you getting an overboost spike like that briefly at the top of spool would be relatively normal, especially at higher RPMs.

Secondly, when you are going WOT from say 2500 RPMS, your car is probably adding WGDCs (effectively increasing target boost) because it is probably below target and thinks by adding WGDCs it'll get to its target. This will cause it to, at spool, over shoot its boost target and then downward WGDC correct will kick in and brings your boost back in line. If upward boost correct is turned on (it is on the stock tune, but custom tunes usually have it turned off) you will often see this small overboost spike.

So bottom line is, I think it's normal. 25 seems a bit high, but a combination of colder weather + wot at high RPMs and I would assume 25 is reachable on the stock tune.
 

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Discussion Starter · #16 ·
well again this happend but the other day it started spiking 27-28 psi and it is hot outside. then today it was spiking 25 like normal but holding 18-19 psi to redline... is this safe? i have a highflow filter uicp and a greddy tic catback. and a autometer gauge
 

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you have a high flow filter, upper intercooler pipe and catback exhaust on a stock tune? it might be time soon to get a protune or etune and in the process diagnose whats goin on with your boost. 28 sounds quite high for a stock map.
 

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25psi sounds too high. My phone app freaks out and gives me a warning when I tag 23.1...it happens every now an then, but never 2x a week or anything.
 

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I have a GS 3port sitting in my tool box, and have a FMIC and LICP sitting around waiting for tune day. Just need to buy a tp/hfc first.
 
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