MCX symptom on APEX Whats wrong?

[Boost It]

My 8BU00 are 49 grams on the gram scale plus i added 9 grams appox total = 58 grams.
snowy1 is right - they are more aggressive.
We throttled up very slow to 7100 rpm and it stopped climbing. It didn't matter whether we ran below 8lbs of boost or 14lbs.
Yes we used 100% race gas.
We also changed all the sparkplugs (thinking that we might have fouled one)

 

[joel0920]

When mcx calibrate weights on Apex they go for 90 gr each for sea level
maybe take off 10gr for 10000feet

problem or not? you are way to low on weights !

apex with turbo has that high torque that it can handle it! go from the above limit and test downwards (start heavy)

 

[SUPERTUNER]

Check to see if your stick coils/sparkplug caps are arcing. When it builds boost, you increase compression, when you increase compression you get what is called "electronic noise" in the airwaves. When you get "electronic noise" you get signals scrambled back to the ECU.

 

[rxrider]

Ok you bring it up to 7000 rpm slowly, not WOT, and still run into problems. Weights are not the problem, you know that already. Have you been in contact with MCXpress about this issue? If not, call or email them, they do know them turbos .... there was a problem with the electronics on the early kits.

 

[hot rod rooster]

sounds like an electronic problem to me. do you know anyone with a differant box you can try?

 

[Boost It]

STILL NOT WORKING!!!!!!!

 

[hooper]

Try to open fuelcap ,if its not topfilled,to check for a pinched ventline.
But maybe you already done that.

 

[Turbo Tim]

Ok you bring it up to 7000 rpm slowly, not WOT, and still run into problems. Weights are not the problem, you know that already. Have you been in contact with MCXpress about this issue? If not, call or email them, they do know them turbos .... there was a problem with the electronics on the early kits.

I've got one of the first 3 kits ,perfect from day one ........Is the crankcase vented properly ?, ..........blowing the valve cover gasket out is very strange .

 

[rxrider]

Turbo Tim - You are probably right that there were no problems on the Apex kits at all. I had it from another post in here somewhere, something about the fuel mapping on high boost

 

[Stubble Jumper]

Check your blow off valve. I Had to replace my intercooler and they forgot to put the plate back in beetween the blow off valve and the intercooler and it would run great to 7000 rpm and then start poping like cray. Installed new plate and everything worked great. Just a thought

 

[snowfix]

the 8bu-00,s are alot more aggressive which means you can run less wieght in them, depends on what boost he is running, I am running 18lbs with them welded up to 61 grams at 10,000-10,200 rpm at 10,000 ft.

Where do you add the weld weight? I assume unddearneath as close to the tip as possible

 

[Thrusted Vector]

Boost it,we came across a problem very similar, and the the plug in to the cdi box had water in it and that's what was causing it to not rev past 7000.

 

[Boost It]

My MCX Turbos are working.
Brandon at CookCityMotorSports Cook City,Montana has fixed the problem.
It was not an install problem.
It is a fuel delivery problem.
The symptoms where:
1. a bottom end stumble or cough.
2. a 7000 rpm stumble or cough which caused the machine to surge.
How did Brandon achieved the fix?
Buy adding an EFI control box to alter the stock efi fuel delivery. (take a little here, add a little there).
Cold air intake (extended with an elbow to exspose the K&N fliter outside, back of the exhaust side cover).
Locate the air box air temp sensor out side .
Very Special THANKS to Brandon.

 

[rxrider]

Boost It - Then I was kinda right about the electronics, fuel mapping was off. Glad to hear it is running well now

 

[ken_climb]

Boost it....what fuel controller did he use? Boondocker or tfi?