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Loosing Boost?

bluboy
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bluboy Enthusiast

bluboy

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Hi everyone, my r32 has an rb25det conversion done by previous owner. I have owened it for about two weeks now. I have done the usual services, oil change, auto trans flush and new spark plugs. Now the thing I am noticing is when under hard acceleration it wont boost past 6.5lb or seven if I'm luckily, its okay reving through the low to Med range but as soon as the revs get high it feels like its spitting or missing, when I take my foot off the the gas a little it kicks back in, slightly. I have checked all vacume lines I could see, which are all silicon hoses with no ties? The coil packs are stock as far as I can see but I would like to find out if it could be more basic before I fork out the cash for new coil packs. Any help would be great or directions to similar threads.

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StealthX Veteran

StealthX

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Might help to tell us how much boost you SHOULD be running mate lol. 6-7psi is normal for 25s if my memory serves me correct...

Have a look for an exhaust leak, and/or boost leak.

Boost leak can indeed cause your missing/spitting, and an exhaust leak can cause a lack of boost/laggy feel

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bluboy Enthusiast

bluboy

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Lol sorry I'm running a gizzmo EBC. Set to 9.7lb, I noticed that the silicone pipe that connects the intercooler pipe to the factory inTake pipe on top of the motor has a tiny gap on either side of the tube, I'm not sure if this is due to them being over tightened or the clamps are not closing strait. How much gap would it take to loose that much boost? As far as the exhaust goes it factory dump pipe to 3" cat back. My mechanic put it up on the hoist and did not notice any exhaust problems, it looks pretty new actually.

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StealthX Veteran

StealthX

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Yeah even the tiniest of leaks can cause a mass fire in RB engines, because they are MAF sensored...

Do you have a pic of said silicone coupler?

How old are your spark plugs?

They could be fouled and not firing properly, the boost is blowing out the poor spark if so, this would prevent your engine from making more boost.

Go through the length of your exhaust and check for studs that are loose, specifically the head-manifold and manifold-turbo ones.

Other than that, have a look at your spark plugs, replace that silicone coupler if it looks like its leaking, and double check all the vacuum hoses and electronics are working for the EBC. Maybe even try to disconnect the wastegate actuator and take it for a spin. Watch your boost gauge very closely and see if you can boost above 7psi. Not the safest method, but it will rule out if your EBC is the problem...

Good luck bro!

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FLN75S Mentor

FLN75S

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Oh and do just diconnect the actuator from the solenoid or do I need to block it up?

I would leave the actuator alone you can just turn your boost controller off and that should run wastegate pressure, would be a lot safer.

Still sounds like it could be coils, what gap is your plugs? 0.8mm is the standard most people run with standard coils.

Other than thats if its pulling smooth but boost is tapering off would just likely be able to fix that by playing with the settings on the boost controller.

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bluboy Enthusiast

bluboy

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Ok, I have bypassed the EBC and noiticed it still holding boost but still maxing out at 5 sometimes 6lb. It doesn't "seem" to be plaining out or spitting now but there was a fine line between it spitting and not spitting.

what could be going wrong with the ebc? Could it have dual high and low settings

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bluboy Enthusiast

bluboy

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Okay, I have installed all new clamps on piping and ties on vac lines. Now its hitting boost a lot better but its still spitting, it only seems to do it when putting my foot right down, but not when i accelerate just a little, so I'm assuming that's why its still not hitting its full boost.

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bluboy Enthusiast

bluboy

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Dang namit! I think this could be my problem. The plugs I was recommended by the ngk book were BCPR6ES, standard copper. but the plugs I pulled out are BKR5EIX, iridium. Now which ones should I be using? BKR5 or BCPR6? Also what is the difference between the two? Besides being copper and iridium.

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bluboy Enthusiast

bluboy

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Dang namit! I think this could be my problem. The plugs I was recommended by the ngk book were BCPR6ES, standard copper. but the plugs I pulled out are BKR5EIX, iridium. Now which ones should I be using? BKR5 or BCPR6? Also what is the difference between the two? Besides being copper and iridium.

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StealthX Veteran

StealthX

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The 5 and 6 (i.e. the number) is the heat rating of the spark plug. The higher the number, the hotter the plug, and warmer plugs are used for turbo cars because boost causes more combustion chamber heat. If your book recommends you run the 6s, and your current plugs are 5s, then this would certainly be your problem...

Make sure they are gapped correctly though, the gap should be listed in the NGK book you've been reading.

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