SOHCex20

I have a 99 ex with the greddy 15g kit and a jrc 6" I/C, lightend flywheel, act clutch, and a mugen twin loop cat back. As of 2 weeks ago I noticed that when I get on it throughout 1st-3rd when I shift, boost doesn't want to climb at all after banging into the next gear. It spools and boosts just fine if I'm crusing in lets say 3rd at like 50 or 60mph and get on it, but if I'm racing and shift from 1st to 2nd or 2nd to 3rd, boost wont increase at all and just rides at about 4psi. I checked for any possible boost leak, but that doesnt explain the fact that it boosts very well if I get on it like I said just rolling in a gear. My next assumption is the wastegate. Now I don't know how to check if its ok, or if thats whats malfunctioning, but I have a MBC but don't know what to disconnect to check if its functioning properly. If anyone knows of this problem, it would be great to hear your imput on the situation. The turbo itself has 15k on it, and no shaft play at all, and spins freely at idle even. Could a restriction of oil be a cause of it too??? Any help would be great. Thanks

SOHCex20

I forgot to add, I'm using an SAFC with DSM 450's as my fuel set up, at roughly 8-10psi. I'm really hoping this is somethign easy and someone else has come across, but I'm starting to think it has something to do with my wastegate. I thought maybe small boost leak, or even just the hot weather, but I drove it when it was 60 degrees the other night and it still did the same thing. Any help would be great.

solowb5

try getting new spark plugs. also your mbc migh be bad. to check the wastegate just take the mbc off and take the hose that is connected to the compressor housing and hook it to the wastegate. also is this a external or internal wastegate

SOHCex20

Just put in new 2 step colder ngk's about 2 months ago(3000 miles). Now when i take that hose off, there is going to be no limit on the boost correct?? And if it spools up correctly then my wastegate is fine, but the MBC is bad?? I want to get a EBC soon, just figured this would hold up until i had enough cash for it.

By the way, its internally gated

solowb5

there will be a limit for the boost as the stock wastegate spring is usually between 5-7 psi. when u use that mbc it is putting alot of stress on that spring so it could be worn out also. if u plan on boosting high then i might also try a external wastegate or see if u can upgrade the spring inside. there are a few options really

SOHCex20

Where can I come across a wastegate spring for the greddy 15g? or would most any spring for internally gated turbos work? I'm going to look aroudn on here about it, but if you could save me some time if you know off the top of your head that would be great. thanks

SOHCex20

well i took off both hoses for the boost controller and it spools insanly fast and before I know it its almost at 15 psi by 4500 rpm. Now would that mean my MBC is messed up? Like I plugged vac line, or just the controller itself?? I'm not sure how it can allow boost up to 10 psi at WOT while rolling in a gear but shifting at redline into 2nd or 3rd doesnt allow it to boost past 4psi.

solowb5

im not following what ur saying. did u take the mbc off and now its spooling fast or what?

SOHCex20

correct. I took it completely off of the compressor housing, and the other hose as well. What I came across is that on the brass fitting that screws in on the side of the MBC has a small hole, almost like a bleed hole on the nut part where you can put a 13mm wrench on it, and when I blow into the hose, I can feel the air coming out of it, where the brass fitting on the bottom of the MBC doesnt have that little tiny bleed hole. Is that supopsed to be there, or can that be considered a small boost leak??? Just curious. If you dont understand what I'm talking about Ill try to explain more clearly in more detail again.

SOHCex20

well i took off my MBC and took the spring, check ball, and that other piece that is between the spring and the screw top and ever since, I have the boost set at 10psi and it holds better than ever. Weird??? Could the spring or ball gotten stuck in place, or possibly messed up in any way? That is the only thing I can think of but I think the new profec S is going to be on its way. Any good things to say about the new Profec S or doesnt anyone have it yet??