Boost spike really bad, should I get 34mm flapper or go external gated

[cruisintalonawd]

I had my boost set at about 14psi and yesterday it started spiking. In first it will go to 20ish, 2nd-5th 17ish. What do you think I should do, I already have ported the O2 housing, manifold and exhaust housing. Its a 14b.

 

[mochilli]

i bought a $10 boost controller off ebay months ago, so im assuming i should just buy an actual good boost controller and not bother with this crappy ebay one? (it looks likes made of wood almost ) heres a link to the item:
R TURBO BOOST CONTROLLER MANUAL ECLIPSE TALON EVO - (eBay.ca item 180244964688 end time 27-May-08 13:07:30 EDT)

mine came with only the unit, no tubing or anything...

 

[cruisintalonawd]

ok so i barrowed a hallman b/c from a friends and she still spikes.....i then just unplugged the wastegate(don't bi*** at me please) and it still goes to 20 then 15 in 2nd higher the gear hight it spikes to. why would this be? the turbo spins so freely that when i blew in the exhaust housing with my mouth is spun for a good 30 seconds it wasnt a really hard blow but a nice suttle one

 

[SethA]

If you have done a boost leak up to the pressure you are trying to run, the only thing I could think of is a bad waste gate actuator. I don't know if you have one you could swap in to test.

Seth

 

[JusMX141]

How do you have your MBC set up? It should go between the nipple on the j-pipe and the wastegate actuator- NOT from the blowoff valve line. Tapping into the blowoff valve line can cause a huge delay in opening the wastegate, which will lead to a boost spike.

I think the MBC is your issue. I tested one of those eBay boost controllers on my workbench once because I suspected it to be at fault on a customer's car. I used an air compressor to blow air into the inlet, while an air pressure gauge on the opposite end told exactly what pressure the MBC was limiting the pressure to. I absolutely could NOT get it to make a consistent number twice between 12 and 20psi. I'd set it to 20psi, back it out 1/8th turn and I'd be at 12. They're touchy, and I don't have the patience or time to mess with something that unreliable.

 

[cruisintalonawd]

how can you say the MBC when there isnt even a BC hooked up? and I have elimated all the B/L

 

[SethA]

The only way boost can drop if there is not a boost leak is for the wastegate to open or maybe a remote chance the turbo is somehow bad. The only thing that I can think of is the flapper is somehow blowing open because the wastegate actuator isn't holding it closed. Why it would ever build any boost I don't know? Perhaps there is a threshold where the pressure in the exhaust manifold is sufficient to blow the flapper open.

You have already tried running without a boost source to the WGA. I would CAREFULLY go one step further and manually hold the flapper shut. If you can't make any boost then I have no idea WTF

Seth

 

[gsxeclipse97]

My boost controller is also crazy. 1st 11psi, 2nd 13psi, 3rd 13psi, 4th 15psi, 5th 12psi Its a turbonetics one but it is on its way out the door i may just hook my 14b back up to the bcs untill i get a better boost controller.