Need some input. Built a tii block, RA classic seals, solid corners, Race springs, big streetport, big exhaust ports etc.. basically, nicely built motor.

Specs:
Rtek 1.7
Rewired Walbro 255
550/750 injectors
Modified stock fuel rails
Adjustablr fpr
44psi base fuel pressure
Stock s5 turbo/ported wastegate
8psi max boost
No emissions
Stock 7/9 spark plugs
Stock coils

Cruising is fine, idle is fine, wot is fine under light load in 1st/2nd

Cruise AFR: ~14-15.5
Boost AFR: ~10.8-11.2

Now the issue is, when I go for a hard pull in any gear, it will break up, and seemingly detonate. Even when afr's are in the low 11's. Actually it will even break up in vacuum!!! I can NOT figure out wtf the problem is. Tried two different harnesses, And rechecked every ground. I also just installed a restrictor pill, and that didn't help either.

My car just breaks up under load, no idea why. Afr is fine, and actually quite rich. What could I be over looking???

 

We usually recommend a stage 2 with any ported motor because you will need to tune to get it running right.

The only thing I can think of is bad timing, or weak coils. What plugs are you running and are they gapped correctly (if you can gap them)?

 

Stock 7/9

I'm suspecting a weak coil as well. Hopefully that is the issue. The car runs GREAT beside the break up, and the rtek makes me feel a lot safer than the stock ecu

I understand that I need full tuneability to pull all the power out of this motor, I'm simply running the rtek on low boost to get the car going, and driving while I save for a real upgrade. Whether it be a 2.1 or anything else.

 

Did you check to make sure the CAS is stabbed right? When it was built was it done with a known good hub/pulley combo?

When I first got my tii on a 3" exhaust it would hit 13.4afr and not break up at 8psi.

 

Yup, It's in there right :/

 

Did you ever solve this issue? Mine seems to be doing the same thing. I keep pulling fuel, but it seems to hit a wall around 6 psi and 5800 in vacuum, starts sputtering won't accelerate. At first I thought it was too rich. Now I'm thinking more that its ignition issue

 

Mine was ridiculous vacuum issues. Basically the fpr, pressure sensor and everything else that needed to be hooked up WASN'T. And the timing was WAY off.

Drives fine now.

You could try all 9 plugs, and make sure your injectors are working correctly. I had an NA injector do exactly what you're experiencing at 5800 because it was bad.

 

I'll pick up some new plugs tonight. See if that helps i had the injectors serviced. I'll check the clips are on tight. Thanks