Lacking Power

[Kansei240sx]

She was running pretty strong untill i did the timing, it was actually advanced quite a bit, and i set the idle for 15 +/- 1 degree and it would get on it, and from idle to 5000 the car pulls a bit less than it did with really advanced timing, THEN when i hit 5000 rpms the power band is just completely flat. all the way to 7000 its slow and doesnt pull whatsoever like it did with the timing really advanced. The problem is, the timing was set to something like 40 degrees a little way to advanced, and the idle was around 2000 rpms. So i messed with the Idle air control valve and then set the idle for like 900. So it idles better....

Im using an adjustable FPR set to 44 psi btw.

I dont have any boost leaks and im around 7-8psi @ the manifold, i dont have any vacuum leaks untill after the car has been driven for over an hour becuase something heats up and makes the tube or w/e expand causing a leak, that i still need to find. I am also not running a thermostat for the last few days and the next few becuase im cleaning out all the crap in my coolant system.

Has anyone encountered this problem/know a fix? Or know what this is, like... a lean spot or rich area, or.... idk... its freaking annoying becuase its nowhere near as fast as it should be and WAS after i did the timing, i pulls great to 5k and then after 5000 you can feel it just stop making power and torque, like its being restricted.

[Shocker]

hmm, im not sure, heres for reference, my RB is a little flat from 5500-59ish-60 k im guessing thats when the VVT is kicking in, or i have my boost solienod hooked up wrong, but it definitally donesnt feel like it lacks anything... do a leak down or compresson test make sure its getting good #'s thats a start, then start questioning spark plugs, you replace them right and gapped to .8mm? also on the timing you sure you set it correctly, and that your notch on the cover isnt worn off, i know i scraped mine off on accident its like choak almost, if so you might have retarded it. re check the timing too. hope something works out for you.

[Kansei240sx]

I know for certain that i did timing right, and i am not dead positive that my VTC solenoid is engaged at all in the first place. I sent my harness to wiring specialties. As far as timing goes i advanced it 5 degrees or so from what it is stock around 20 degrees. I just replaced the spark plugs with the new engine like a few weeks ago gapped to .8 .

Im going to take it to the dyno this weekend and see what my afr is and see if i can figure this out.

I should do a compression test although my car idles smooth and doesnt show any signs of bad compression. Wouldnt hurt to do it anyways.

[Imissmyturbo]

My story about timing on my RB25...........he other week I errased my PFC maps and put them back to stock. I then set base timing to 15 degree's. Then I did the adjustments for my mods. 480cc injectors and Q45 MAF. When I would give it full throttle around 5000-redline it would stumble and run like crap. I then went on the PFC menu and advanced the timing 1 degree at a time. I had 5 degree's in it when it started to run really good. Better then ever. My A/F's are between 10.9:1 and 11.5:1 under full boost. I then went to the track and ran a 12.9 @ 115 but on that pass at the top of fourth I got 89 on the knock moniter. So I feel that the timing may need 5 degree's in some places on the map but less at others. But to sum things up. Timing on RB motors sucks!!! I wouldn't hesitate if I were you to bump the timing up 2-3 degree's. I bet it will make a huge difference.

[Kansei240sx]

Ill give that a shot, i am advanced from stock 4-5 degrees but i guess another 2,3 or 4 degrees couldnt hurt.

I just dont want to advance it too terribly much because my idle will start going up. I have the AAC valve turned ALL the way down and it STILL idles at 900

[Joe]

Ill give that a shot, i am advanced from stock 4-5 degrees but i guess another 2,3 or 4 degrees couldnt hurt.

I just dont want to advance it too terribly much because my idle will start going up. I have the AAC valve turned ALL the way down and it STILL idles at 900

dude your gonna run 24 degrees of advance? are you insane?

set it at 16 and leave it alone. you are gonna cause havok turning your timing up that far. you have no way of monitoring detonation and you are making a DRASTIC change to timing. 8 degrees above stock is a lifetime in engine rotation. RB's are very hyper sensitive to timing, BE CAREFULL.

RB25's have very small turbos. of course its not gonna run as strong above 5000 at stock boost.

[Kansei240sx]

I know that, but IT IS FREAKIN SLOW as hell after 5000 the power band shouldnt end at 5000....

[Joe]

what boost are you running

and it does have a drop off after 5000.

[Vkoslak]

maybe I dont know what the hell I am talking about, but isnt 44psi on the fuel line high for idle? I set my rb20det psi to 36 at idle. Do you have a way of telling if you are running rich?

[Kansei240sx]

Im runing 7-8 psi @ the manifold and no it does not drop off whatsoever.

As for knowing if its lean or rich, im doing to dyno it and hook it up and get an AFR reading.

[Yellow4g63]

Are you getting any codes? like bad Crank angle sensor? or knock sensor?

[Shocker]

h

maybe I dont know what the hell I am talking about, but isnt 44psi on the fuel line high for idle? I set my rb20det psi to 36 at idle. Do you have a way of telling if you are running rich?

hes running that with the VAC line off.