PSI problem

[cano86]

This is strange I have my MBC set to 15PSI but here is the problem when I hit the gas full throttle the psi shoots up to 15 but after a few seconds its start going down am not suffering any power loss but the pounds just drop I did a boost leak and everything seems to be ok, it dont sputter or anything just drops any help is appreciated thank you guys

 

[djalogik]

could help you out more if you listed your mods in you profile.

 

[cano86]

This car is stock since I havent owned it for a long time and it spent most of its time in the parking lot with burned wiring harness. All it has is an Injen style intake,Greddy type BOV,MBC,APEXXI 3.5" exhaust system,AEM cam gears and aftermarket Boost gauge thats about it. Soon going with FMIC,650 injectors,walbro 255FP,and Cams.

 

[xdxoxuxgx]

Probably boost spike, what does the boost drop too after it falls from 15?

 

[cano86]

When it starts going down it sets at ten and it wont go any lower than that.

 

[onlyhonestone]

how exactly did u check for a boost leak, it sounds like a boost leak to me......

 

[2GAWD4U2NV]

What size turbo? If it's factory T-25, then it will not hold the amount of boost you want to run, mainly in the higher rpms. The larger the turbo, the better it holds boost towards higher rpms. There is a big difference just from the T-25 to the 14b. The 14b hold boost a lot better than the T-25, and it only gets better from there. So if you are on the T-25, that is an explanation why.

 

[xdxoxuxgx]

If its the T-25 you're probably just boost spiking and then falling off in higher rpms since its so small.

 

[cano86]

The turbo in it is the 14b

 

[redline2k6]

it sounds like a boost spike my car does the same thing spikes to 26 then settles at 22psi on a 16g

 

[cano86]

when the car is at idle the vacum is set a 19 and wont go know where and when i down shift it while running the vacum goes to 23 I think if it wouldve been a boost leak it would affect the vacuum right, most likely I will take the boost spike advise thanks guys

 

[the_mork]

If the car settles down to 10 psi right away after 15 psi then you are probably just having a big spike and you've inadvertently set your mbc to 10 psi by looking at the spike as your general boost number. The problem is that you are likely to spike even higher if you aren't careful in trying to raise that boost. Where is your boost source for your mbc coming from? Is there anything else on that line? Is the distance between the boost source and the wastegate fairly short? The vacuum lines too? If so then I would slowly *very slowly* start raising the boost until you get to the point that you want, your boost spike may not rise in a 1:1 ratio with your regular boost so just keep track of both your continual boost and your boost spike since you don't want a boost spike causing knock or otherwise overboosting your setup in general.

Another possibility is a bad bov depending on how you do your boost leak testing. I knew exactly what it was as soon as it happened but I had my forge bov stick open for a bit and that is exactly the way that it acted but I could hear the air rushing through my recirculation tube.

Edit: I also noticed on your parts wishlist that you would like some Pulstar plugs for your car, I wouldn't suggest doing that since you wont find any gain. Save that money and use it for something else.
http://www.dsmtuners.com/forums/han...on-watts-pulstars-again-merged-snake-oil.html

 

[cano86]

Another possibility is a bad bov depending on how you do your boost leak testing. I knew exactly what it was as soon as it happened but I had my forge bov stick open for a bit and that is exactly the way that it acted but I could hear the air rushing through my recirculation tube.

Edit: I also noticed on your parts wishlist that you would like some Pulstar plugs for your car, I wouldn't suggest doing that since you wont find any gain. Save that money and use it for something else.
http://www.dsmtuners.com/forums/han...on-watts-pulstars-again-merged-snake-oil.html[/QUOTE]

I always hear the air rushing through my recirculation tube. The MBC is set from the turbo housing to the wastegate is that a recommended place to put it on.

The plugs am talking about is not those damn e3 spark plug I hate e3 I installed them in my car once and two days later had to rebuild my cylinder head because the freakin spark plug broke in pieces and crushed my valves so e3 are not an option going through my head , and if the pulstars are going to be a pain in the ass to get I;ll just get NGK"s

 

[2GAWD4U2NV]

You need to have the sufficient exhaust components before trying to run more boost. That catback will help, but it's not doing what a full 3" turboback will do. If you are on the factory o2 housing and downpipe with cat, you still have to much back pressure. Forced induction you want to get rid of back pressure. This increases spool time and decreases boost spike.

There are a couple of ways to fix this. First of all, complete your exhaust before getting more advanced parts. That includes bigger o2 housing, downpipe, and catback. Then you can get a better flowing exhaust manifold. Forced Performance sells a great on. That would hold any boost the 14b can put out. You can still improve by putting on an open dump o2 housing, or upgrading to an external wastegate set-up.

Once you complete you exhaust system, you should have eliminated your boost problems. If not, you have a boost leak and/or bad bov. Always check your ICP. It's the easiest. Then you can go from there.

 

[darkhorizon]

NGK plugs are the only way to go, cheap, and they make tons of power without idle issues. You also have a few options of how you can set them up and gap them.

 

[cano86]

You need to have the sufficient exhaust components before trying to run more boost. That catback will help, but it's not doing what a full 3" turboback will do. If you are on the factory o2 housing and downpipe with cat, you still have to much back pressure. Forced induction you want to get rid of back pressure. This increases spool time and decreases boost spike.

There are a couple of ways to fix this. First of all, complete your exhaust before getting more advanced parts. That includes bigger o2 housing, downpipe, and catback. Then you can get a better flowing exhaust manifold. Forced Performance sells a great on. That would hold any boost the 14b can put out. You can still improve by putting on an open dump o2 housing, or upgrading to an external wastegate set-up.

Once you complete you exhaust system, you should have eliminated your boost problems. If not, you have a boost leak and/or bad bov. Always check your ICP. It's the easiest. Then you can go from there.

All my components are 3.5 except the o2 housing. I had it all set up without a catalytic converter but had to install one for emission should I remove it again.

 

[xdxoxuxgx]

The stock cat is very restrictive and could easily be the cause of your boost spike.

 

[cano86]

The cat is not stock though

 

[the_mork]

That thread only starts out discussing e3 plugs, it goes on to discuss pulstars later in the thread. There is absolutely no plug that will run better in these cars than a copper NGK.

 

[dsmmikej]

Another possibility is a bad bov depending on how you do your boost leak testing. I knew exactly what it was as soon as it happened but I had my forge bov stick open for a bit and that is exactly the way that it acted but I could hear the air rushing through my recirculation tube.

I have the same exact problem with my forge bov. I've got full 3"exhaust, big16g, mbc, fmic, and k&n, running stock ecu and fuel system.
Always boosted to 22psi and set to 16psi, now it'll spike to 16-14psi then drop to like 8-6. i'm not quite sure, but my bov isn't near as loud as it used to be and it barely blows off during normal driving. It sounds weak to me. think i'm gonna ditch it for a 1g and recheck my mbc.

GOOD LUCK! This is giving me inspiration (for the moment) to get my car smoking tires again!

 

[cano86]

Well my Bov when I bought it had 2 fittings in the back one on top of the other but the bottom one broke of and is opened to air now that I remember could that be a possible reason if yes then am just gonna replace the BOV

 

[2GAWD4U2NV]

Well my Bov when I bought it had 2 fittings in the back one on top of the other but the bottom one broke of and is opened to air now that I remember could that be a possible reason if yes then am just gonna replace the BOV

What type of bov do you have. Could very well be.

 

[cano86]

I have a Greddy style BOV

 

[the_mork]

Possibly, does the hole push out or pull in air at idle? How about during a boost leak test?

 

[Boostjunki84]

I have a Greddy style BOV

Do you mean, like an e-bay knock-off? I agree with the above that the BOV may not working correctly.