High Rpm's, why? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

shayrgob240 · 07-10-2005, 09:47 AM

Hey!

I just bought a 95 240sx w/ a rb20det. I dont know if the tach is messed up or if the car is supposed to be revving high. I drove the car on the highway and i was going fairly slow(60-65) and the rpm's were at about 4K and if i went a little faster it was at 4.5K. The speeds that i have listed are just a rough estimate b/c the speedo is messed up from the swap. Can you guys tell me what the norm is for the rpm's when on the highway? thanks!

PS- The reason why i think this is abnormal is b/c of my last car(eclipse gst) that was always at around 3K when on the highway.

EEdude · 07-10-2005, 10:16 AM

For a 6cylinder, RPMs around 60mph should be roughly 2,500. The guy who had it before you probably changed the final drive to something a lot lower, for quicker accleration.

shayrgob240 · 07-10-2005, 11:05 AM

well, im not sure what the guy before me did w/ the car and i really have no idea how to really find out. So, i have 2 questions:

1) How do i find out what happened if the previous owner doesnt know.
2) Does that not put a lot of stress on the engine if continously driving w/ the rpm's at 4.5K

thanks!

Maeda · 07-10-2005, 12:50 PM

Taller final gear?

OR

Broken Speedo.

JDMs13 · 07-10-2005, 02:14 PM

Does it sound like 4K? Prolly has japanese final drive out back. When Im on the highway just takin it easy, Im at 4K also. Sucks on highway, but worth it everywhere else. Kinda forces you to keep it around 60-65, at least for me it helped. That and the japanese speed warning bell thingamigigy.

TheSnail · 07-10-2005, 02:27 PM

Its like this. 89-90 tach does not work. 91+ works, but its horrably inaccurate. The higher the rpm on the tach the more inaccurate it gets. Im sure you pin the tach quite easy. Well, buy the time its showing 7k rpm, the motor is only turning at 5.5k. Get a tach from a skyline and it will work flawlessly.

shayrgob240 · 07-10-2005, 05:29 PM

ok, I'll try and get the cluster in ASAP. thanks!

420sx · 07-10-2005, 06:41 PM

why just not get a aftermarket tach and wire it into the speed sensor?

TheSnail · 07-10-2005, 06:48 PM

Quote:

Originally Posted by shayrgob240

ok, I'll try and get the cluster in ASAP. thanks!

You dont need to instal the cluster, just unscrew the three screws that hold the tach in, trim the plastic on the rb20 tach a little, then place it in your 240 guage cluster.

TheSnail · 07-10-2005, 06:55 PM

Like this, here's a pic one of mine, takes 10min.

shayrgob240 · 07-10-2005, 06:55 PM

that sounds like a good idea but the problem is that the speedo is screwed b/c its trying to read k/ph instead of MPH. So i was thinking that if i swapped in my skyline cluster it would solve the problem since it would be meant for it. Or is there a way to get the stock cluster to read the proper speed? thanks!

TheSnail · 07-10-2005, 06:58 PM

Use the stock KA speed sensor. The trannies are the same. So the stock one just bolts on.

allstar · 07-10-2005, 07:05 PM

my friends s14 with a rb25 does the same shit.. At freeway speeds hes rpms are around 5k, and then if he punches it the rpms go all the way to 8k and stays there for 1 sec intill he has to shift.. I always thought that shit was off or maybe the ecu was tuned b4 he got it.

07-10-2005, 09:47 AM	#1
shayrgob240 Zilvia Junkie Join Date: Jul 2003 Location: gurnee, IL Age: 39 Posts: 441 Trader Rating: (0) Feedback Score: 0 reviews	High Rpm's, why? Hey! I just bought a 95 240sx w/ a rb20det. I dont know if the tach is messed up or if the car is supposed to be revving high. I drove the car on the highway and i was going fairly slow(60-65) and the rpm's were at about 4K and if i went a little faster it was at 4.5K. The speeds that i have listed are just a rough estimate b/c the speedo is messed up from the swap. Can you guys tell me what the norm is for the rpm's when on the highway? thanks! PS- The reason why i think this is abnormal is b/c of my last car(eclipse gst) that was always at around 3K when on the highway.

07-10-2005, 12:50 PM	#4
Maeda Nissanaholic! Join Date: Dec 2002 Location: Camp Snake Bite, CA RIP Posts: 2,356 Trader Rating: (0) Rides Gallery: Maeda Feedback Score: 0 reviews	Taller final gear? OR Broken Speedo. __________________

07-10-2005, 02:27 PM	#6
TheSnail Nissanaholic! Join Date: Jan 2004 Location: Marietta Georgia Age: 41 Posts: 2,434 Trader Rating: (0) Feedback Score: 0 reviews	Its like this. 89-90 tach does not work. 91+ works, but its horrably inaccurate. The higher the rpm on the tach the more inaccurate it gets. Im sure you pin the tach quite easy. Well, buy the time its showing 7k rpm, the motor is only turning at 5.5k. Get a tach from a skyline and it will work flawlessly. __________________

07-10-2005, 06:41 PM	#8
420sx Post Whore! Join Date: Jun 2004 Location: Texas Age: 41 Posts: 3,960 Trader Rating: (0) Rides Gallery: 420sx Feedback Score: 0 reviews	why just not get a aftermarket tach and wire it into the speed sensor? __________________ hydropgrahics! ls1......

07-10-2005, 06:55 PM	#10
TheSnail Nissanaholic! Join Date: Jan 2004 Location: Marietta Georgia Age: 41 Posts: 2,434 Trader Rating: (0) Feedback Score: 0 reviews	Like this, here's a pic one of mine, takes 10min. __________________

07-10-2005, 10:16 AM	#2
EEdude Leaky Injector Join Date: Mar 2004 Location: 510 Posts: 71 Trader Rating: (0) Feedback Score: 0 reviews	For a 6cylinder, RPMs around 60mph should be roughly 2,500. The guy who had it before you probably changed the final drive to something a lot lower, for quicker accleration.

07-10-2005, 11:05 AM	#3
shayrgob240 Zilvia Junkie Join Date: Jul 2003 Location: gurnee, IL Age: 39 Posts: 441 Trader Rating: (0) Feedback Score: 0 reviews	well, im not sure what the guy before me did w/ the car and i really have no idea how to really find out. So, i have 2 questions: 1) How do i find out what happened if the previous owner doesnt know. 2) Does that not put a lot of stress on the engine if continously driving w/ the rpm's at 4.5K thanks!

07-10-2005, 02:14 PM	#5
JDMs13 BANNED Join Date: Feb 2005 Location: New England Age: 40 Posts: 271 Trader Rating: (0) Feedback Score: 0 reviews	Does it sound like 4K? Prolly has japanese final drive out back. When Im on the highway just takin it easy, Im at 4K also. Sucks on highway, but worth it everywhere else. Kinda forces you to keep it around 60-65, at least for me it helped. That and the japanese speed warning bell thingamigigy.

07-10-2005, 05:29 PM	#7
shayrgob240 Zilvia Junkie Join Date: Jul 2003 Location: gurnee, IL Age: 39 Posts: 441 Trader Rating: (0) Feedback Score: 0 reviews	ok, I'll try and get the cluster in ASAP. thanks!

07-10-2005, 06:58 PM	#12
TheSnail Nissanaholic! Join Date: Jan 2004 Location: Marietta Georgia Age: 41 Posts: 2,434 Trader Rating: (0) Feedback Score: 0 reviews	Use the stock KA speed sensor. The trannies are the same. So the stock one just bolts on. __________________

07-10-2005, 07:05 PM	#13
allstar Zilvia Junkie Join Date: Oct 2004 Location: Azusa, cali (626) Age: 38 Posts: 326 Trader Rating: (0) Feedback Score: 0 reviews	my friends s14 with a rb25 does the same shit.. At freeway speeds hes rpms are around 5k, and then if he punches it the rpms go all the way to 8k and stays there for 1 sec intill he has to shift.. I always thought that shit was off or maybe the ecu was tuned b4 he got it.