Car won't hold boost, low power.

[acidflux]

I have a big 16g with a mbc and full 3" stainless turbo back with an evo 3 manifold. Stock ecu/injectors, VRSF FMIC, FIAV blocked tb and a hacked 1g maf. Full ffwd fuel system installed too, fuel pressure at 37.5 psi.

The car ran fine at stock boost after several upgrades so I decided it was safe to crank it up a bit. I went to 12psi, everything fine. 15psi, everything fine, sometimes it would drop to 14psi but still good. I upped the boost again and it only spikes now and hovers at 14-15psi.

Also, the power was nice and strong until I swapped out the stock o2 housing for a bigger stainless unit. The turbo spools sooner now but the seat of the pants power feels less.

Lastly the clutch slips slightly in 5th now if I boost under 3500 rpms.

Could this loss of perceived power be minor clutch slippage? I don't see/hear any noticeable rpm changes. It just feels weak. I've double checked fuel pressure and boost leak checked it plenty. Turbo gaskets are all good too. I can't imagine a larger o2 housing could lose power... Injectors going out? I have yet to hit fuel cut.

 

[throwedgsx]

I would turn your boost back down to safe levels for your stock injectors. I'm sure they're way over 80% duty cycle.

 

[acidflux]

I forgot to add, the boost spikes to 17psi then drops to 15 or so until 4th and 5th gear, then it barely gets past 15psi and drops to 14 usually, sometimes 13.

One more thing... On part throttle boost you could feel the power difference between varying boost levels before. Now anything past 12lbs doesn't feel like anything is happening in the horsepower department.

Maybe I got some bad fuel and its pulling timing due to knock? My eprom ecu fried so no logging.

 

[throwedgsx]

Without any way of logging and actually knowing what is happening with your engine and a/f ratios. It is much more safe to turn your boost back down to stock level. Which on a 1g is ~11....idk not a 1g guy myself. See what happens, if it feels right again then i would bet you were knocking. Besides you're not seeing any benefits by running unsafe boost levels as you stated it doesn't feel any more powerful. And it will save a lot of headache in the future if something happens.
Ryan

 

[acidflux]

Well, it DID run fine at the higher boost level... As soon as I swapped the o2 housing everything changed, I'm baffled. If I run the wastegate straight with no boost controller my gauge reads 7ish psi.

 

[canada4g63]

What are you using to tune? Do you have a logger? Does your car throw any CEL's?

 

[acidflux]

No CELs, my dsmlink setup fried so I'm on stock ecu/injectors. Base boost with no boost controller is 7psi. Anything past 10 and it spikes then falls back. The worst I've seen so far is 15psi spike and falling to 10psi.

If I slowly roll into the boost I can almost get it to stay up, only losing 1psi or so, but if I crack on the throttle, big spike, big drop. All the other dsms I've been around hold boost at whatever its set at, this is a first for me. I wonder if my mbc is dirty or something crazy like that.

It ran fine before, then it just started doing this...

 

[acidflux]

Solved I guess... I did the dodge garage mod to my stock bov and tried both the fast release and the port open. In fast release mode, same problem, losing boost. I removed the boost source from the modded port and the boost holds right at 15, or where ever I set it. I'll just keep the mods coming, since they seem to be fixing all my bugs...

 

[gusu]

If you run passed 10 PSI on a 16g you are over running your injectors and the gasoline will wash the grease from your bearings eventually causing you to spin one. Plenty of people have done it in the past, I'd learn from their mistake personally than make it my own.