sr20DET speed cut.. is it possible to...? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

IAGguy · 04-08-2003, 03:27 PM

is it possible to pull the speed meter pin out of the ECU without loosing the speedo? especially since i have the digital speedo/HUD...
cause this 115 mph bull**** ****es me off!!!!!

AKADriver · 04-08-2003, 03:50 PM

yes.

the speed signal goes VSS -> speedo -> ECU.

IAGguy · 04-08-2003, 03:55 PM

im not sure what you mean... is it possible to pull the pin and NOT lose the speedo...? and if so which wire is it...? keeping in mind it is a S13 SR20DET

nrcooled · 04-08-2003, 04:22 PM

For $70 you can have this

I have heard things about just cutting the speed signal to the ecu since the ECU has no functions that are speed dependant but personally I would just shell out the money for the Greddy Fuel Cut defenser

AKADriver · 04-08-2003, 06:03 PM

Like I said...

The speed signal goes from the sensor, to the speedometer, to the ECU.

If you pull the wire out of the ECU, the signal will still go from the sensor to the speedometer. The speedometer will still function.

The wire is yellow with green stripes.

AKADriver · 04-08-2003, 06:20 PM

Quote:

Originally posted by nrcooled
For $70 you can have this

I'm looking into that thing... not just to buy for myself, but it's probably pretty easy to build if it works the way I think it does.

In the meantime, another good fuel cut solution would be to wire a switch into the yellow/green wire so that the ECU still gets the speed signal on the street, but then you can switch it off at the track. I'm not 100% sure there's no speed-related stuff that the ECU does besides the fuel cut.

The A'pexi Rev/Speed Meter also has a fuel cut eliminator built in. That's a great solution since it's more accurate than the stock speedometer and doesn't stop at 115.

*sykikchimp* · 04-08-2003, 06:28 PM

What is the revlimiter on a Sr20?

If it's like the KA, it's only a few hundred RPM over the fuel cut..

I personally don't think those things are worth $70 for 5 mph...

AKADriver · 04-08-2003, 06:40 PM

7700rpm IIRC... maybe it was 7500?

You might run out of 4th gear right after the speed cut, but 5th should be good for a bit longer.

s14vaxlr8 · 04-08-2003, 06:42 PM

the sr with that greddy soeed cut is good atleast to 150

*sykikchimp* · 04-08-2003, 06:49 PM

SR's 5th gear Rev limiter is 7500rpm! wow.. I could see the rev limiter being there in neutral, or in first gear or something, but generally the rev limits get lower in each gear..

What RPM is the Fuel cut at?

AKADriver · 04-08-2003, 07:01 PM

Ah, I see your line of thought. The rev limit in 1st-3rd is 7700... I was assuming you would have unplugged the 4th and 5th gear sensors as well. With those disconnected and some sort of fuel cut eliminator your top speed would be limited only by aero drag.

autobahNESSA · 04-09-2003, 12:42 AM

115?
ive had mine way past 115mph. i dont know how fast it will go but ive been to the point where the guage stops moving then i backed off.
the revlimiter on my sr is 7600.

Steeles · 04-09-2003, 07:54 AM

Quote:

Originally posted by sykikchimp
SR's 5th gear Rev limiter is 7500rpm! wow.. I could see the rev limiter being there in neutral, or in first gear or something, but generally the rev limits get lower in each gear..

What RPM is the Fuel cut at?

yeah My SR hit the speed cut on the Dyno in 4th gear at like 6800RPM

ibanezxguy · 04-11-2003, 11:43 AM

so what is everybody getting for top end speed out of sr motors?

s14vaxlr8 · 04-11-2003, 12:08 PM

Quote:

Originally posted by ibanezxguy
so what is everybody getting for top end speed out of sr motors?

i hit the odometer reset on my 96, didnt look at the avc-r for speed though

Steeles · 04-11-2003, 01:15 PM

Quote:

Originally posted by ibanezxguy
so what is everybody getting for top end speed out of sr motors?

115 havent you been paying attention?

Cadence · 04-11-2003, 01:35 PM

Ok just want to clarify here? Does it work or doesnt it.. Cutting the wrie that leads to the ECU? And if there isnt any speed dependant devices that the ECU reads then why run a wire to the ECU telling it what speed your going other than for the speed limiter? Is that the wires only function? And I beliece technical fuel cut is at 7800 on the SR per the FSM. Tachs tend to be off quite a bit.

AKADriver · 04-11-2003, 02:59 PM

Cut that wire + disconnect 4th and 5th gear sensors = no limit.

Does the VSS signal to the ECU have any other function? mmmmmmaybe, probably not... often these are used to control things like fuel cut on deceleration... on some cars (not the 240SX) it's used to control the fans.

If it bothers you to cut that wire, take the suggestions in the posts above (Greddy delimiter, simple switch, A'pexi rev/speed meter). The Greddy and the A'pexi work by shutting off that VSS signal only when it goes above 112, leaving it on otherwise, so the ECU still sees it in normal driving.

Cadence · 04-11-2003, 08:32 PM

OK.. but why should I need to disconnect the sensors? If I cut the wire then the ECU doesnt have a clue what my speed is right? Or does it? ANd will I still have a rev limiter at 7800 in 4th and 5th gears?

gregsr20 · 04-12-2003, 02:06 PM

get the greddy speed cut sensor, i tried both options, had slight problems with the cut wire, some reason my speedometer was quirky

04-08-2003, 03:27 PM	#1
IAGguy Join Date: Dec 2002 Location: CT, U.S.A. Age: 41 Posts: 32 Trader Rating: (0) Feedback Score: 0 reviews	sr20DET speed cut.. is it possible to...? is it possible to pull the speed meter pin out of the ECU without loosing the speedo? especially since i have the digital speedo/HUD... cause this 115 mph bull** es me off!!!!! __________________ Nine90 Performance Engineering http://www.nine-90.com Intense Auto Graphics & Signs** http://www.intenseautographics.com

04-08-2003, 03:55 PM	#3
IAGguy Join Date: Dec 2002 Location: CT, U.S.A. Age: 41 Posts: 32 Trader Rating: (0) Feedback Score: 0 reviews	im not sure what you mean... is it possible to pull the pin and NOT lose the speedo...? and if so which wire is it...? keeping in mind it is a S13 SR20DET __________________ Nine90 Performance Engineering http://www.nine-90.com Intense Auto Graphics & Signs http://www.intenseautographics.com

04-08-2003, 04:22 PM	#4
nrcooled Nissanaholic! Join Date: Mar 2002 Location: Turn 8 'bout to get rolled by a SC'd ITR Age: 45 Posts: 1,849 Trader Rating: (0) Feedback Score: 0 reviews	For $70 you can have this I have heard things about just cutting the speed signal to the ecu since the ECU has no functions that are speed dependant but personally I would just shell out the money for the Greddy Fuel Cut defenser __________________ '91 hatch w/ SR Sold; '03 Evo Sold 401 HP; '03 MS Protege sold; '00 Evo 6.5 TME Sold 300HP

04-08-2003, 06:28 PM	#7
sykikchimp WOW addicted Join Date: Dec 2001 Location: the moon Age: 43 Posts: 6,525 Trader Rating: (0) Feedback Score: 0 reviews	What is the revlimiter on a Sr20? If it's like the KA, it's only a few hundred RPM over the fuel cut.. I personally don't think those things are worth $70 for 5 mph... __________________

04-08-2003, 06:42 PM	#9
s14vaxlr8 Zilvia Junkie Join Date: Nov 2001 Location: DC Metro Age: 42 Posts: 522 Trader Rating: (0) Feedback Score: 0 reviews	the sr with that greddy soeed cut is good atleast to 150 __________________ 96 Kouki w/sr20det for sale http://www.zilvia.net/f/showthread.php?t=66164

04-08-2003, 03:50 PM	#2
AKADriver Post Whore! Join Date: May 2002 Location: Springfield, VA Age: 42 Posts: 3,475 Trader Rating: (1) Feedback Score: 1 reviews	yes. the speed signal goes VSS -> speedo -> ECU.

04-08-2003, 06:03 PM	#5
AKADriver Post Whore! Join Date: May 2002 Location: Springfield, VA Age: 42 Posts: 3,475 Trader Rating: (1) Feedback Score: 1 reviews	Like I said... The speed signal goes from the sensor, to the speedometer, to the ECU. If you pull the wire out of the ECU, the signal will still go from the sensor to the speedometer. The speedometer will still function. The wire is yellow with green stripes.

04-08-2003, 06:40 PM	#8
AKADriver Post Whore! Join Date: May 2002 Location: Springfield, VA Age: 42 Posts: 3,475 Trader Rating: (1) Feedback Score: 1 reviews	7700rpm IIRC... maybe it was 7500? You might run out of 4th gear right after the speed cut, but 5th should be good for a bit longer.

04-08-2003, 06:49 PM	#10
sykikchimp WOW addicted Join Date: Dec 2001 Location: the moon Age: 43 Posts: 6,525 Trader Rating: (0) Feedback Score: 0 reviews	SR's 5th gear Rev limiter is 7500rpm! wow.. I could see the rev limiter being there in neutral, or in first gear or something, but generally the rev limits get lower in each gear.. What RPM is the Fuel cut at? __________________

04-08-2003, 07:01 PM	#11
AKADriver Post Whore! Join Date: May 2002 Location: Springfield, VA Age: 42 Posts: 3,475 Trader Rating: (1) Feedback Score: 1 reviews	Ah, I see your line of thought. The rev limit in 1st-3rd is 7700... I was assuming you would have unplugged the 4th and 5th gear sensors as well. With those disconnected and some sort of fuel cut eliminator your top speed would be limited only by aero drag.

04-09-2003, 12:42 AM	#12
autobahNESSA Zilvia FREAK! Join Date: Aug 2002 Location: Milpitas/Irvine, CA Posts: 1,257 Trader Rating: (3) Feedback Score: 3 reviews	115? ive had mine way past 115mph. i dont know how fast it will go but ive been to the point where the guage stops moving then i backed off. the revlimiter on my sr is 7600.

04-11-2003, 11:43 AM	#14
ibanezxguy Zilvia Member Join Date: May 2002 Location: Augusta,Ga Posts: 176 Trader Rating: (0) Feedback Score: 0 reviews	so what is everybody getting for top end speed out of sr motors?

04-11-2003, 01:35 PM	#17
Cadence Join Date: Jan 2003 Location: Bellingham, Wa Posts: 17 Trader Rating: (0) Feedback Score: 0 reviews	SPeed CUt Ok just want to clarify here? Does it work or doesnt it.. Cutting the wrie that leads to the ECU? And if there isnt any speed dependant devices that the ECU reads then why run a wire to the ECU telling it what speed your going other than for the speed limiter? Is that the wires only function? And I beliece technical fuel cut is at 7800 on the SR per the FSM. Tachs tend to be off quite a bit.

04-11-2003, 02:59 PM	#18
AKADriver Post Whore! Join Date: May 2002 Location: Springfield, VA Age: 42 Posts: 3,475 Trader Rating: (1) Feedback Score: 1 reviews	Cut that wire + disconnect 4th and 5th gear sensors = no limit. Does the VSS signal to the ECU have any other function? mmmmmmaybe, probably not... often these are used to control things like fuel cut on deceleration... on some cars (not the 240SX) it's used to control the fans. If it bothers you to cut that wire, take the suggestions in the posts above (Greddy delimiter, simple switch, A'pexi rev/speed meter). The Greddy and the A'pexi work by shutting off that VSS signal only when it goes above 112, leaving it on otherwise, so the ECU still sees it in normal driving.

04-11-2003, 08:32 PM	#19
Cadence Join Date: Jan 2003 Location: Bellingham, Wa Posts: 17 Trader Rating: (0) Feedback Score: 0 reviews	hrmmm OK.. but why should I need to disconnect the sensors? If I cut the wire then the ECU doesnt have a clue what my speed is right? Or does it? ANd will I still have a rev limiter at 7800 in 4th and 5th gears?

04-12-2003, 02:06 PM	#20
gregsr20 Zilvia Member Join Date: Jan 2003 Location: SAVANNAH, GA. Age: 41 Posts: 155 Trader Rating: (0) Feedback Score: 0 reviews	get the greddy speed cut sensor, i tried both options, had slight problems with the cut wire, some reason my speedometer was quirky __________________ fast cars are dangerous, save lives drive HONDA'S