Hey,

I just finished a turbo swap on my 83 280zx. The engine is from a 81 & runs great, starts up quick and runs smooth.. my only problem is nomatter what i do it refuses to go past 4-5 lbs of boost.

I've triple checked for vacuum leaks and everything is solid. I've also plugged the pov, blocked the egr replaced the fpr, put new plugs and wires, dizzy cap + rotor and double checked the timing.

Right now i have no exhaust besides the stock downpipe, but i don't think that would impact anything. I'm also using a aftermarket boost gauge and mbc. I had the mbc given to me... it looks like a ebay pos and when i took it apart there was no spring and ball.. just a rod that screwed down to block air.. here's a pic of it.

Also this is currently hooked up on the wastegate / intake. I've also tried it on the turbo with no difference.

beyond that all i can really think of is a faulty wastegate actuator, it seems pretty tight and in working order.

any ideas here? this is driving me nuts.

 

Moved thread to S130 280zx section since your car isn't an S30.

#1: MBC's suck. They aren't reliable.

#2: Are you sure your aftermarket boost gauge is working correctly? Do you still have the stock boost gauge hooked up?

#3: Put your emergency release valve (POV) back on, shut the boost controller completely, and see if it will then boost higher (the POV will open and chirp wildly when boost gets to about 8psi.

 

ahh sorry for posting in the wrong place.

I'll try those things later on tonight and post back up

thanks!

 

You know the turbo is good?

If the car is not getting enough fuel, it may be cutting power out, and will not boost well either.

 

the turbo spools like a champ and sounds like a harrier jet when i drive so i'm assuming it's good to go.

I'm going to go close the mbc and drive it in a few, then just plug the wastegate actuator to see what happens.

I'll be super careful though and if i see it go past 5 I'll assume it's the ebay mbc.

pray for me

 

Make sure you re-install the POV!

 

loud turbo isn't always good, loud could mean its dying or its spooling so damn high trying to compensate for a boost leak. no bueno! try removing the MBC all together and just route the line from the compressor to the waste gate like stock see if that solves the problem. and with a line you know has no leaks in it

 

well the turbo is loud because the car is currently rolling with no exhaust.

i took it out and here's what happened....

with the mbc hooked up and closed there was no difference.. 4-5 and thats it.

I took the hose off of the wastegate and i would get around 5-6 psi, the boost gauge flutters around like mad then I hear a crazy chirping noise coming from under the left side of my hood, followed by a dramatic loss in power. I'm assuming thats the pov kicking in and saving my engine from disaster.

The car definately isn't hitting 8 or 9 psi so could that be a old faulty pov?

Also now that i think about it the last fuel pump on my car died while it was n/a and i replaced it with what i think was a turbo one.

 

If i was going to do a leakdown check.. the best way is to just get a pvc cap, rubber coupler, clamp and a tire air valve, right?


It's been awhile since i've done that and just wanted to make sure.

 

After driving it a few times here's what i think it is.

i get flawless happy gofast boost until 5 psi, after that i notice the engine gets a bit boggy and the power goes away. My money says that i still have a n/a fuel pump from the original 83 setup and possibly a faulty pov. I put the plug back in and took it for a drive and it did perfectly fine until the 5 psi bog point.

That fuel pump definitely wouldn't keep up with the turbo and engine at that point, right?

what fuel pump should I replace this with for optimal fuel delivery so this will never be a problem again?

 

from the sounds of that could also be the AFM. MAYBE!!! does it hit a certain RPM and then just sit and bounce and sputter there? if so what rpm?

 

it all ties around the 5 psi point from what i've seen, never noticed any problems otherwise.

Just kinda seems like the fuel system is like "what the ****?!?!" when boost hits too hard and the fuel pump can't keep up.

I've ran the rpm up to about 5500 with no issues whatsoever. Whats a decent pump to get on these? I'm assuming a walbro or something to that effect.

 

Stock is find but doesn't hurt to upgrade maybe the have a 255lph in line pump if so I would go with that

 

I went ahead and picked up a walbro gsl392 255 fuel pump + a new boost controller. Hopefully this makes my car happy.

 

I got the fuel pump and boost controller in and that seemed to fix it!

The car is fast, hits 7-8 psi and feels great. The only thing i may need to do is plug the pov... whenever it's hooked up the car leaks boost out around 6 psi and when it's plugged everything is wonderful.

Also.. I ran some seafoam through my intake and I thought the fire dept was going to get called on me lol! that stuff smokes like a ****.

 

sure does! and good to hear.

 

quick question.

Are these cars going to make a purge noise like a bov after you let off the pedal?

I noticed my car spools up then makes a blow off noise when i let off from full boost. I'm not a turbo noob by any means but i've never seen a car that blows off with no bov.

The only thing i can think of is my wastegate opening since I am currently running open turbo for exhaust and it's just F'n loud to begin with.

 

do you have an aftermarket filter on? you might just be hearing compressor surge. does it make a pulsating sound of air not to loud but noticeable almost sounds like a pulsating whine or higher pitched grunt?

http://www.youtube.com/watch?v=nCj6Spwl1CU


this one is a bit more realistic for your application its the quick woopapapa. sound.

http://www.youtube.com/watch?v=OuNTnA5A2Fo


and here to, this car has no BOV on it so you can't mix the two sounds up its ALL surge in this video

http://www.youtube.com/watch?v=LZUbo...eature=related

 

That sounds like the noise to me. I take it thats pretty normal then?

Thanks for the response! This is by far the best z forum on the net imo.

 

its normal if you don't have a BOV or an improperly set BOV. it can start to mutate the compressor blades over time but at that low of boost it would take a while to do damage.

 

mine doesn't have the flutter to it.

It sounds more like greddy type s, or when he got on it in the 2nd video @ 26 seconds and it was a high pitched "PCHHAAAAAAA"

 

is it with the POV installed? maybe your popping it then. compressor surge flutters.

 

i have a plug where the pov is located at. It seemed to leak prematurely.

 

What the ****s a turbo?

 

i'll record a video and throw it on youtube tomorrow so there's no misinformation about how it sounds on my end.

thanks again.