rb25 problem - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

240sxwanted · 09-21-2010, 05:57 PM

Ok ive noticed that when my rb25 is not warmed up all the way, it pulls nicely and doesn't bog or lag as mush as when the engine is warmed up. When its semi cold i can get on the gas and it wont bog and lag. When the temperature needle is at the halfway point, i hit full throttle and it seems to pull not as hard as when its not fully warmed up. It also bogs a little. Its pretty much a stock rb25 except for isis intake manifold, fmic, rb25 turbo w/rb20 actuator (10 psi). I also have the stock skyline radiator and some rubber hoses, and has the original spark plugs that came with the engine, if that info helps determine the problem. Anyone else with an rb25 has experienced this?

burninrubber85 · 09-21-2010, 06:59 PM

ok ive worked on many rb's. i could be a number of things such as heat soaked turbo. the isis manifold is robbing you of power because its to great of a volume of air flow. the stock manifold makes more power and torque over greedy freddy manifolds unless the engine has been built. a fuel pump could also be getting hot. timing could be off (bogging). What is your full pressure when it gets hot and when its cold? Where is the cas(cam angle postion sensor) postion in the grove(left, right, middle). have you tried different mafs?

240sxwanted · 09-21-2010, 07:30 PM

not running a boost gauge currently, i've only tried the maf i have on right now. you think the fuel pump could be getting hot? here's a pic of how the cas sits, but dont think it could be timing. It only does it when its warm...

240sxwanted · 09-22-2010, 09:11 AM

anybody have any input? i need to know what might be causing this so i can fix it.

09-21-2010, 05:57 PM	#1
240sxwanted Zilvia Junkie Join Date: Mar 2009 Location: Santa Fe, NM Posts: 311 Trader Rating: (11) Feedback Score: 11 reviews	rb25 problem Ok ive noticed that when my rb25 is not warmed up all the way, it pulls nicely and doesn't bog or lag as mush as when the engine is warmed up. When its semi cold i can get on the gas and it wont bog and lag. When the temperature needle is at the halfway point, i hit full throttle and it seems to pull not as hard as when its not fully warmed up. It also bogs a little. Its pretty much a stock rb25 except for isis intake manifold, fmic, rb25 turbo w/rb20 actuator (10 psi). I also have the stock skyline radiator and some rubber hoses, and has the original spark plugs that came with the engine, if that info helps determine the problem. Anyone else with an rb25 has experienced this? Last edited by 240sxwanted; 09-21-2010 at 08:44 PM..

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09-21-2010, 06:59 PM	#2
burninrubber85 Join Date: Apr 2007 Location: tampa, fl Posts: 30 Trader Rating: (0) Feedback Score: 0 reviews	ok ive worked on many rb's. i could be a number of things such as heat soaked turbo. the isis manifold is robbing you of power because its to great of a volume of air flow. the stock manifold makes more power and torque over greedy freddy manifolds unless the engine has been built. a fuel pump could also be getting hot. timing could be off (bogging). What is your full pressure when it gets hot and when its cold? Where is the cas(cam angle postion sensor) postion in the grove(left, right, middle). have you tried different mafs?

09-21-2010, 07:30 PM	#3
240sxwanted Zilvia Junkie Join Date: Mar 2009 Location: Santa Fe, NM Posts: 311 Trader Rating: (11) Feedback Score: 11 reviews	not running a boost gauge currently, i've only tried the maf i have on right now. you think the fuel pump could be getting hot? here's a pic of how the cas sits, but dont think it could be timing. It only does it when its warm...

09-22-2010, 09:11 AM	#4
240sxwanted Zilvia Junkie Join Date: Mar 2009 Location: Santa Fe, NM Posts: 311 Trader Rating: (11) Feedback Score: 11 reviews	anybody have any input? i need to know what might be causing this so i can fix it.