Got a few questions about mods - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

docrice · 02-17-2003, 05:50 PM

Well, i'm starting to mod my car and i have a few questions, any advice would be appreciated.
First: I want to do a full exhaust on my 240. I already decided on Hotshot headers and probably a random tech cat, and since i'm NOT going turbo i want to go with either 2.25" or 2.5" tubing after that. I want something that sounds good, NOT too loud or raspy. I'd like a dual tip that looks at least pseudo-stock. i don't care whether it's muffler only or cat back, since i know a guy that does custom bends...muffler only would be preferable,mainly for the cost factor, which i would like to keep this fairly inexpensive. so i'd like your reccomendations, sound clips would be GREAT if possible.
Second: I tried to remove the speed limiter on my car as reccomended on the 240sx.org FAQ's and got a check engine light. my car is a 96 and they seem to say it would only affect Cali. cars. Is there a way i can trick the ECU or fake a sensor input? My idea was to use a switch to control either input direct from the sensor to ecu or input with an amp/resistor, depending on how its measured, and just hitting the switch once i near the speed limiter. any ideas/personal experience would be great

Dream240 · 02-17-2003, 05:58 PM

The Hotshot, Random tech cat is the way I went and those parts alone cost me about 550.00. 250.00 for the headers and 220.00 for the cat, plus you need to order the O2brackets for your 2nd O2 sensor from Hotshot. That part is a pain in the ass. I had to take the part and my car down to a weld shop that would actually do the quick weld for me. Most shops wont. And I went with the Apexi N1 dual, but my cars REALLY loud, with no silencer. Get one if you decide that route trust me.

Good Luck!

95Blue240sx · 02-17-2003, 08:21 PM

thats weird. i have the hs header and it eliminates the cat. the only place there would be to add a cat is between the header and rest of the exhaust. i know that there is a resonator right there, right under the driver seat.

Dream240 · 02-18-2003, 12:13 PM

Actually you're partially right. The HS header removes the only TRUE CAT on the OBD II 240. The second canister that looks like a CAT, just after the new HS header, is actually hollow!! Just a guess but I'd say that Nissan used it for something else in Japan and just brouht the version straight over for us. When you but a High flow CAT from Random Technologies, or whomever, it will replace this hollow piece. Also the Random Tech CAT comes with flared flanges that don't require a gasket, just bolt it up to the header and exhaust and you're in business. I actually went to the local hardware store and bought 4 matching nuts, lock washers, and bolts for the CAT to bolt up between my header and N1 exhaust. It's funny but all the after market parts actually fit better together than the stock pieces did!
Oh yeah, remove the stickers on the CAT cause they'll just burn off and smoke the first time you drive off and probably freak you out. Don't forget that you'll need to move your second O2 sensor to the exhaust behind the new CAT or you'll get an engine light that will ultimately lean out your mixture and make you run really ****ty.

Have fun and good luck!

*AceInHole* · 02-18-2003, 02:23 PM

Just a heads up: I've got a friend running a '97 with no 2nd O2 sensor and his CEL came and went. Car runs fine. He has a JWT ECU though. I had my 2nd O2 sensor unplugged on 2 seperate occasions and the CEL never came up (maybe not enough key cycles to trigger it).

*Jeff240sx* · 02-18-2003, 02:48 PM

Screw the CEL. I've had one on my car for months. It's bitching about 3 things.. and I don't really care.
And yea... HS/hi-flow cat/exhaust is the only way to go NA.
-Jeff

Dream240 · 02-18-2003, 05:47 PM

Yeah the JWT ECU will avoid that problem because you can fine tune your fuel mixtures. Also the light will not trigger for about 1000 miles, but once it does, and you reset it, without fixing the problem, it will come back on almost immediately. Smart little suckers!!

I'm looking into a JWT ECU, but maybe later. Jeff I feel you on the ECU, when I first bought mine I had failed a speed sensor, leaking intake manifold, and bad O2 sensors. That light got so annoying that I just put a little black electrical tape over it until I got them fixed. Was much nicer at night!!

madwilly240 · 04-12-2005, 01:23 PM

so when I install my HS header, and my RSR cat back, theres still gonna be a stock piece in there between the 2?

And the random tech cat will take care of that? Catco would be the same too right..?

Replicant_S14 · 04-12-2005, 01:37 PM

Quote:

Originally Posted by madwilly240

so when I install my HS header, and my RSR cat back, theres still gonna be a stock piece in there between the 2?

And the random tech cat will take care of that? Catco would be the same too right..?

yes and yes

02-17-2003, 05:50 PM	#1
docrice Zilvia Junkie Join Date: Jan 2003 Location: central PA Age: 39 Posts: 416 Trader Rating: (0) Feedback Score: 0 reviews	Got a few questions about mods Well, i'm starting to mod my car and i have a few questions, any advice would be appreciated. First: I want to do a full exhaust on my 240. I already decided on Hotshot headers and probably a random tech cat, and since i'm NOT going turbo i want to go with either 2.25" or 2.5" tubing after that. I want something that sounds good, NOT too loud or raspy. I'd like a dual tip that looks at least pseudo-stock. i don't care whether it's muffler only or cat back, since i know a guy that does custom bends...muffler only would be preferable,mainly for the cost factor, which i would like to keep this fairly inexpensive. so i'd like your reccomendations, sound clips would be GREAT if possible. Second: I tried to remove the speed limiter on my car as reccomended on the 240sx.org FAQ's and got a check engine light. my car is a 96 and they seem to say it would only affect Cali. cars. Is there a way i can trick the ECU or fake a sensor input? My idea was to use a switch to control either input direct from the sensor to ecu or input with an amp/resistor, depending on how its measured, and just hitting the switch once i near the speed limiter. any ideas/personal experience would be great __________________

02-17-2003, 05:58 PM	#2
Dream240 Nissanaholic! Join Date: Dec 2002 Location: Inland Empire, California Age: 45 Posts: 2,188 Trader Rating: (8) Feedback Score: 8 reviews	The Hotshot, Random tech cat is the way I went and those parts alone cost me about 550.00. 250.00 for the headers and 220.00 for the cat, plus you need to order the O2brackets for your 2nd O2 sensor from Hotshot. That part is a pain in the ass. I had to take the part and my car down to a weld shop that would actually do the quick weld for me. Most shops wont. And I went with the Apexi N1 dual, but my cars REALLY loud, with no silencer. Get one if you decide that route trust me. Good Luck! __________________ Don't mess with my monkey...he's loaded.

02-17-2003, 08:21 PM	#3
95Blue240sx Post Whore! Join Date: Jul 2002 Location: Girls pee-pee when they see me Age: 40 Posts: 4,084 Trader Rating: (0) Rides Gallery: 95Blue240sx Feedback Score: 0 reviews	thats weird. i have the hs header and it eliminates the cat. the only place there would be to add a cat is between the header and rest of the exhaust. i know that there is a resonator right there, right under the driver seat. __________________ Please leave me feedback

02-18-2003, 12:13 PM	#4
Dream240 Nissanaholic! Join Date: Dec 2002 Location: Inland Empire, California Age: 45 Posts: 2,188 Trader Rating: (8) Feedback Score: 8 reviews	Actually you're partially right. The HS header removes the only TRUE CAT on the OBD II 240. The second canister that looks like a CAT, just after the new HS header, is actually hollow!! Just a guess but I'd say that Nissan used it for something else in Japan and just brouht the version straight over for us. When you but a High flow CAT from Random Technologies, or whomever, it will replace this hollow piece. Also the Random Tech CAT comes with flared flanges that don't require a gasket, just bolt it up to the header and exhaust and you're in business. I actually went to the local hardware store and bought 4 matching nuts, lock washers, and bolts for the CAT to bolt up between my header and N1 exhaust. It's funny but all the after market parts actually fit better together than the stock pieces did! Oh yeah, remove the stickers on the CAT cause they'll just burn off and smoke the first time you drive off and probably freak you out. Don't forget that you'll need to move your second O2 sensor to the exhaust behind the new CAT or you'll get an engine light that will ultimately lean out your mixture and make you run really ****ty. Have fun and good luck! __________________ Don't mess with my monkey...he's loaded.

02-18-2003, 02:23 PM	#5
AceInHole Autox Technician Join Date: Dec 2001 Location: New Haven, CT Age: 43 Posts: 3,961 Trader Rating: (0) Rides Gallery: AceInHole Feedback Score: 0 reviews	Just a heads up: I've got a friend running a '97 with no 2nd O2 sensor and his CEL came and went. Car runs fine. He has a JWT ECU though. I had my 2nd O2 sensor unplugged on 2 seperate occasions and the CEL never came up (maybe not enough key cycles to trigger it). __________________

02-18-2003, 02:48 PM	#6
Jeff240sx I hate you too... Join Date: Jul 2001 Location: Tampa, FL Age: 41 Posts: 5,828 Trader Rating: (0) Rides Gallery: Jeff240sx Feedback Score: 0 reviews	Screw the CEL. I've had one on my car for months. It's bitching about 3 things.. and I don't really care. And yea... HS/hi-flow cat/exhaust is the only way to go NA. -Jeff __________________ Whatup?

02-18-2003, 05:47 PM	#7
Dream240 Nissanaholic! Join Date: Dec 2002 Location: Inland Empire, California Age: 45 Posts: 2,188 Trader Rating: (8) Feedback Score: 8 reviews	Yeah the JWT ECU will avoid that problem because you can fine tune your fuel mixtures. Also the light will not trigger for about 1000 miles, but once it does, and you reset it, without fixing the problem, it will come back on almost immediately. Smart little suckers!! I'm looking into a JWT ECU, but maybe later. Jeff I feel you on the ECU, when I first bought mine I had failed a speed sensor, leaking intake manifold, and bad O2 sensors. That light got so annoying that I just put a little black electrical tape over it until I got them fixed. Was much nicer at night!! __________________ Don't mess with my monkey...he's loaded.

04-12-2005, 01:23 PM	#8
madwilly240 Zilvia Junkie Join Date: Dec 2002 Location: na Age: 38 Posts: 331 Trader Rating: (0) Feedback Score: 0 reviews	so when I install my HS header, and my RSR cat back, theres still gonna be a stock piece in there between the 2? And the random tech cat will take care of that? Catco would be the same too right..?