Crome tune choppy at 5K

[A]]Th!ngSound]

Greetings CC.

I have a B18B1 with a typical .50 A/R ebay turbo kit on it with the needed upgrades (tial wg, ngr bov, oil restriction). Log manifold, 450cc blue top dsm's with resistor box, omni 3 bar map sensor, adjustable fpr, aem wideband and a chipped P28 ecu. A good friend of mine that usually tunes with Neptune did some back-n-forth chip burns in Crome for me, adjusting from a B18B1 base map and adding fuel where needed. He adjusted for the bigger injectors, added the boost columns, set it up for the 3 bar.

My problem is the car runs amazing and is much more responsive throttle-wise with good A/F ratios in boost and at idle, but gets really choppy at about 5k RPM's. It doesn't redline or limit it, just seems to lose its power or pull right about then. Wideband reads at 12.5 at 10ish lbs @5,200 RPM's, then weak sauce. Any rough ideas on what to check?

Forgot to add: I'm running NGK 4554's at about .28 gap.

 

[A]]Th!ngSound]

Bump... still having issues.

 

[obracer12]

Any head work done? Valves/retainers?

If not, Seems to me with the added pressures and the higher rpm ranges for the b18 you may be experiencing some float, or the very least some harmonics.

Boost pressure + high engine speed in the non-vtec motors tend to float more than the b16/b18 vtec motors.

Are you experiencing excessive oil burn or building crank pressure?

 

[A]]Th!ngSound]

Any head work done? Valves/retainers?

If not, Seems to me with the added pressures and the higher rpm ranges for the b18 you may be experiencing some float, or the very least some harmonics.

Boost pressure + high engine speed in the non-vtec motors tend to float more than the b16/b18 vtec motors.

Are you experiencing excessive oil burn or building crank pressure?

It's a stock motor aside from 450 dsm's and the turbo kit. I don't think I've ever heard of people having issues with float at 4.5k rpm's with an LS motor on 10 lbs with a small turbo, but I won't say that's not a possibility because I'm lost on what it might be.

 

[Esotericimage]

Do you have the crankcase vented?

Hows the condition of the springs?

Try opening the gap to 32, your not going to blow out at 32.


I would recommend your buddy tuning it on Neptune with his ECU, then burn that map to a chip. forget chrome altogether.

Neptune will also tell you with the data log whats going on with it.

 

[A]]Th!ngSound]

Do you have the crankcase vented?

Hows the condition of the springs?

Try opening the gap to 32, your not going to blow out at 32.


I would recommend your buddy tuning it on Neptune with his ECU, then burn that map to a chip. forget chrome altogether.

Neptune will also tell you with the data log whats going on with it.

I'll give that a shot. He normally tunes with Neptune actually... but it comes with a heftier price tag that I wanted to wait for a little while.

 

[Esotericimage]

IDK why it would be more.. tuning is tuning.

Hes still burning the chip regardless of the program.