Hey guy's my cycle valve was chirping so I replaced it with a new one. The car is now a turd, the boost came up slow. I replaced it with the chirper and it came alive again. Can someone explain this???

 

ditch the cv for a vacuum splice, cap the line going to the intake and be done. The cv is meant to slow the roll on of boost to keep factory cars from being wrecked im sure. Maybe your original cv is defective or modified if the boost comes on fast w/ it on there. Just ditch it and put a coupler in there.

scrap that- you need a MBC doah!

 

Doesn't the CV provide over boost protection though?

 

nope- ditched mine and it still has a boost cut. i believe that is controlled by the klr. - and my klr vac. line is not on either that just controls the boost gauge.

 

The original one had a slight leak when I blew through it plus it was making the chirping noise. Can you explain vacuum splice? Do you mean cap both ends and plug the small vacuum line going to the manifold?

Also I don't see much boost in first gear as 3rd through 5th. Is that normal?

Are you saying that the boost you see on the guage doesent mean it's actual manifold boost?
thanks, Jim

 

you have three lines to the cv.

1. goes down to the wastegate

2. goes to the hardline from to the IC and reads vac or pressure

3. goes back to the intake jboot in front of the turbo

your cv bypasses so much of the boost until --- rpm and then opens up wide to allow for full boost- this just bleeds the boost on slowly as to keep from breaking the tires loose etc...

you can eliminate the cv, unplug the wires- doesnt do anything unplugged- then cap the line going to the jboot as to keep it from leaking vac. I capped mine under the intake for now but eventually the jboot will be gone and so will the vac. line

then splice the line from the wastegate to the line going to the IC and your done. Now when your car gets boost the wastegate reads it, and doesnt hang open allowing boost to leak off. I did this in my car w/ a tial 38mm and MBC and also a stock 951 with lindsey boost enhancer with awsome results.

 

Hmm...wow. Thanks for writing that out Dan! Is this what you should do when installing a Tial as well?

-Darwin

 

Hmmm why haven't I heard about this before? I've heard of people eliminating it w/ the use of a Black **** or whatnot but never on a stock car. Can anyone else varify?

Not that i don't trust you, xboost -- def no offense intended!

 

+1 and how did you cap off the line to the intake boot. Do the line from the IC pipe goes right to the WG. A splicer that is easily picked up at a auto store? This sounds easy but I though MBC was the only way to delete the CV.

 

So what are the wires going into the cv for. You can just unhook it an leave it. What would it do if you left it hooked up but bypassed the cv.

 

I also have a problem with my CV, but I tought that stok WG starts to open at 1.2 Bar absolute pressure. If I'll remove the WG would I hit ~ 1.87 boost pressure?

 

i did this to a stock car w/ no MBC of any kind and boost picked up way faster- no more than stock. I also have mine t-d right there for my MBC. I took the unused vac line and shoved a bolt in the end and zip-tied it on the end. Tricky part is, when you look under the intake at the vac lines, the one that looks like it would go to the intake-towards the ds, actually goes to the IC line, and the one that is towards the ps, actually goes to the jboot. Double check that before you go capping off random lines.

no reason to leave the cv in there unless you plan on hooking it back up - if you just want to try it out, you could take the lines off and leave it in there, but it may be hard to get the lines off w/ the cv still mounted. You can use a vac double barbed fitting to connect the two lines, and a 10mm headed (seat bolts) to shove into the vac line unused.

 

By itself, the factory/stock waste gate will only hold around 1.2-1.4 bar (abs) boost pressure w/o the CV operating correctly. If you bypass the CV and route the banjo line straight to the stock WG, you will have little boost/power.

If you do bypass the CV, you need to install some sort of mechancial boost controller, usually something like a Lindsey Boost Enhancer or Accuboost type pressure relief valve. This limits the pressure to the waste gate, so it wont open prematurely.

The CV is a diverter valve, that controls pressure/flow from the IC runner banjo line to the waste gate. It reduces the pressure to the WG, by bleeding or diverting it back to the intake j-boot by an internal solenoid flapper (the pattern for this is mapped on the KLR chip). If you unhook the wires from the CV, it defaults wide open, allowing manifold pressure directly to the WG, so the WG will open early and you will have little boost.

This is what the KLR does for "limp home" mode - it cuts the power signal to the CV, the CV defaults wide open, allowing manifold pressure to go unrestricted to the WG, and the WG opens allowing only 1.2-1.4 bar abs boost pressure.

Overboost protection is a DME function, its a fuel cutoff mapped on the factory/stock DME chip. DME measures airflow through the AFM across an rpm range, if there is too much airflow compared to a mapped value, it determines there is an overboost problem, and it dumps the fuel. Aftermarket chips raise or eliminate this protection, so you will not encounter it.

 

I've taken several wastegates apart... and the stock one has a large diaphragm on the top with the hose that goes to it. On a properly working wastegate, supplying positive pressure to that hose expands the diaphragm and OPENS the wastegate valve – which then divers exhaust gas AWAY from the turbo and DECREASES boost.

The diaphragm has a pretty large diameter, so not much pressure is needed to open that valve – just a few psi will do it.

If you hook it up as Dan recommends, the boost pressure in the intake system will go directly to this diaphragm and open up the wastegate, and thus decrease boost. The cycling valve’s job, as Jim said, is to keep this positive pressure AWAY from the wastegate until the KLR decides to decrease the boost (either to prevent the boost from exceeding max or to limit it in limp-home mode).

My only explanation for Dan’s experience is something else must be amiss – perhaps a line is clogged, or the wastegate diaphragm is torn. (They do tear, I’ve had to replace them for this.)

If you want a lot of boost pinch off (or completely disconnect) the hose going to the wastegate – this will provide NO positive pressure to open the wastegate, and your car will boost until the exhaust pressure overcomes the wastegate spring. However, the KLR will have no way to reducing the boost – so be careful!

 

yeah i rethought my statement and the wastegate would work, you would get quicker boost, but not full boost. IF you have an aftermarket wastegate w/ a 1bar spring-or larger- you will get whatever the spring is set at. The reason Johnny's worked is because we installed a lindsey boost enhancer the same time. Damnit! I forgot about that!!! oh well i know what i know. What i do know is w/o the CV boost comes on much more quickly. I guess w/o a MBC or some sort of restriction to the pressure going to the WG it will not realize full boost. Sorry.

ive seen people run carburator jets in line to the Wastegate to restrict pressure to the diaphram w/ varying results as well, which is basically what the autothority banjo had.