RB25 crappy throttle response- help - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

abbSC · 08-07-2014, 08:09 PM

Alright guys, I recently got my rb25 back in my car and running but throttle response sucks and Im not sure why. Quick list of mods: tomei drop in cams, HKS adjustable cam gear (EX), top mount manifold, precision sc61, tial 44mm gate, front mount, turbosx RFL Bov, freddy intake, q45 throttle body, top feed rail with bosch 850s, AEM fuel pump, etc. running just off the down pipe right now. Im using a Apex-I power fc w/ map sensor and have the fuel somewhat tuned. The car is drivable but my throttle response sucks. Its slow and not smooth at all like the rb used to be. I can blip the throttle and it takes a second for any response. Now I was told it may be that the car needs to be fully tuned, but a friend was able to get his SR running great with a very similar setup and we didn't touch ignition tuning yet on his. We timed the rb correctly and also experimented with adjusting my exhaust cam. 2 degrees retarted and the car ran even worse and would die coming to a stop. 2 degrees advanced and it runs about the same as at 0 degrees. Any input is appreciated as I am dying to drive this thing.
Thanks

abbSC · 08-12-2014, 08:31 AM

still having trouble..

hobbs · 08-12-2014, 08:40 AM

You throw big injectors, big turbo, aftermarket intake manifold and big TB at it and you're wondering why it's not running right without a tune?

Croustibat · 08-12-2014, 09:12 AM

put that car on a trailer, bring it to a mechanic so he can fix your mistakes (namely set the cams and CAS right, remove boost leaks) , then to a tuner so he can tune it.

And THEN you can drive it.

abbSC · 08-13-2014, 07:05 PM

Quote:

Originally Posted by hobbs

You throw big injectors, big turbo, aftermarket intake manifold and big TB at it and you're wondering why it's not running right without a tune?

Just expected throttle response to be a bit better then it is considering we didn't have this issue with my buddies sr. AFRs are tuned fine

abbSC · 08-13-2014, 07:08 PM

Quote:

Originally Posted by Croustibat

put that car on a trailer, bring it to a mechanic so he can fix your mistakes (namely set the cams and CAS right, remove boost leaks) , then to a tuner so he can tune it.

And THEN you can drive it.

There are no boost leaks, been over everything and the car has good vacuum and holds any boost fine. Cams are timed correctly and so is the CAS. I do need to get it tuned by a pro but I just thought it would run better then it is now.

TwoForDeh · 08-14-2014, 02:00 PM

did you take the vct out when you put the cams in? If you did, rb's are complete dogs low rpm/response wise with no vct let alone being untuned with everything you have.

OBEEWON · 08-14-2014, 02:12 PM

Timing..........

abbSC · 08-14-2014, 02:41 PM

Quote:

Originally Posted by TwoForDeh

did you take the vct out when you put the cams in? If you did, rb's are complete dogs low rpm/response wise with no vct let alone being untuned with everything you have.

VCT is still installed

Sileighty_85 · 08-14-2014, 04:22 PM

needs to be tuned. Power FC Base maps are only intened to be drive to a tuner, not DD'd.Q45 TPS probably needs to be adjusted, if its a Series 2 IIRC S2's will have issues wih the Q45 TPS.

08-07-2014, 08:09 PM	#1
abbSC Leaky Injector Join Date: Jun 2012 Location: Charleston, SC Posts: 51 Trader Rating: (3) Feedback Score: 3 reviews	RB25 crappy throttle response- help Alright guys, I recently got my rb25 back in my car and running but throttle response sucks and Im not sure why. Quick list of mods: tomei drop in cams, HKS adjustable cam gear (EX), top mount manifold, precision sc61, tial 44mm gate, front mount, turbosx RFL Bov, freddy intake, q45 throttle body, top feed rail with bosch 850s, AEM fuel pump, etc. running just off the down pipe right now. Im using a Apex-I power fc w/ map sensor and have the fuel somewhat tuned. The car is drivable but my throttle response sucks. Its slow and not smooth at all like the rb used to be. I can blip the throttle and it takes a second for any response. Now I was told it may be that the car needs to be fully tuned, but a friend was able to get his SR running great with a very similar setup and we didn't touch ignition tuning yet on his. We timed the rb correctly and also experimented with adjusting my exhaust cam. 2 degrees retarted and the car ran even worse and would die coming to a stop. 2 degrees advanced and it runs about the same as at 0 degrees. Any input is appreciated as I am dying to drive this thing. Thanks

08-14-2014, 02:12 PM	#8
OBEEWON Post Whore! Join Date: Feb 2006 Location: Hightened State of Emergency Posts: 6,053 Trader Rating: (9) Feedback Score: 9 reviews	Timing.......... __________________

08-14-2014, 04:22 PM	#10
Sileighty_85 Post Whore! Join Date: Dec 2006 Location: Misawa, Japan Posts: 6,815 Trader Rating: (8) Feedback Score: 8 reviews	needs to be tuned. Power FC Base maps are only intened to be drive to a tuner, not DD'd.Q45 TPS probably needs to be adjusted, if its a Series 2 IIRC S2's will have issues wih the Q45 TPS. __________________ 後輪駆動車１番 1989 Built SR GT2871R -363whp 1998 S14 W/RB25- 250ish (For Now) 1986 SR86 - 200ish 1990 R32 GTR - 320hp Don't Buy Engines from JDM-Online http://zilvia.net/f/businesses/207457-jdm-online.html Don't Buy XS-Power or SSAC Shit

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08-12-2014, 08:31 AM	#2
abbSC Leaky Injector Join Date: Jun 2012 Location: Charleston, SC Posts: 51 Trader Rating: (3) Feedback Score: 3 reviews	still having trouble..

08-12-2014, 08:40 AM	#3
hobbs Nissanaholic! Join Date: Aug 2010 Location: Under a rock Posts: 2,264 Trader Rating: (43) Feedback Score: 43 reviews	You throw big injectors, big turbo, aftermarket intake manifold and big TB at it and you're wondering why it's not running right without a tune?

08-12-2014, 09:12 AM	#4
Croustibat Nissanaholic! Join Date: Aug 2011 Location: France - Toulouse Age: 44 Posts: 1,851 Trader Rating: (0) Feedback Score: 0 reviews	put that car on a trailer, bring it to a mechanic so he can fix your mistakes (namely set the cams and CAS right, remove boost leaks) , then to a tuner so he can tune it. And THEN you can drive it.

08-14-2014, 02:00 PM	#7
TwoForDeh Zilvia Junkie Join Date: Feb 2013 Location: NH Posts: 426 Trader Rating: (0) Feedback Score: 0 reviews	did you take the vct out when you put the cams in? If you did, rb's are complete dogs low rpm/response wise with no vct let alone being untuned with everything you have.