sohc
05-13-2005, 08:16 PM
#1
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Thread Starter
Join Date: Apr 2004
Location: florida
Posts: 116
sohc
i have a 1990 240sx i just bolted on a 4-2-1 header hollowed the cat and an injen short ram, and about 3 months ago i bolted up my apexi n1-dual exhaust i still dont think im getting enogh power , what else can i do to get more horse, can i have ideas plz
05-14-2005, 08:12 PM
#5
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Join Date: Sep 2004
Location: knoxville tn
Posts: 999
the best freebie you can do is get an electric fan... the clutch fan has a lot of drag on the motor when it is locked in... then yes look for cams and an ecu reprogram... get a safc and replace your injectors with bigger units... z32 fuel filter and a better fuel pump and fuel pressure regulator...
05-15-2005, 06:18 PM
#7
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Join Date: Mar 2005
Location: Virginia
Posts: 16
First off
I'm totally new to 240SX's as all I've ever owned / built in the past were 5.0 Mustangs ,so please keep in mind that I know very little about these cars. I have a 90 240SX that I'm about to start circle track racing in a class called Pure Stock 4's ( we are sanctioned by NASCAR so we get tore down and checked....just like the big boys ). Here's my problem...the normal bolt ons are a definate no no. We aren't "supposed " to change anything on the engine . With that being said...what can I do to help get a little extra HP ? We get a 50 # weight break over the twin cam 240's but I'm still down a little on power. The electric fan mentioned sounds good ....can't change cams ( they check them ) . So here's a few questions:
(1) who does ecu reprogramming and how much does it cost ?
(2) what is a safc mentioned above ?
(3) z32 fuel filter ? I just bought a stock replacement filter..so what is different about a z32 ? where can I get one ?
(4) how about one of those " race " underdrive crank pulleys I see listed on E-hay ?
anything else you guys can think of would be greatly appreciated.
I'm totally new to 240SX's as all I've ever owned / built in the past were 5.0 Mustangs ,so please keep in mind that I know very little about these cars. I have a 90 240SX that I'm about to start circle track racing in a class called Pure Stock 4's ( we are sanctioned by NASCAR so we get tore down and checked....just like the big boys ). Here's my problem...the normal bolt ons are a definate no no. We aren't "supposed " to change anything on the engine . With that being said...what can I do to help get a little extra HP ? We get a 50 # weight break over the twin cam 240's but I'm still down a little on power. The electric fan mentioned sounds good ....can't change cams ( they check them ) . So here's a few questions:
(1) who does ecu reprogramming and how much does it cost ?
(2) what is a safc mentioned above ?
(3) z32 fuel filter ? I just bought a stock replacement filter..so what is different about a z32 ? where can I get one ?
(4) how about one of those " race " underdrive crank pulleys I see listed on E-hay ?
anything else you guys can think of would be greatly appreciated.
Last edited by purestock4racer; 05-15-2005 at 06:20 PM.
05-15-2005, 10:46 PM
#8
Contributing Member
Join Date: Jun 2004
Posts: 707
1) JWT makes an ECU for the S13, but its said to be lower than the potential of the car.
2) The SAFC is a unit by Apex'i that will control your air to fuel ratio. Necessary if your running a bigger MAF and injectors.
3) A Z32 fuel filter is bigger than an S13 fuel filter. A Z32 is second generation 300zx. Bigger=better flow=better throttle response.
4) I don't think the underdrive pulleys are that good, unless you buy the whole set.
You can put in some pistons to increase compression, as well as change the MAF, if you can make it look stock. Good luck
2) The SAFC is a unit by Apex'i that will control your air to fuel ratio. Necessary if your running a bigger MAF and injectors.
3) A Z32 fuel filter is bigger than an S13 fuel filter. A Z32 is second generation 300zx. Bigger=better flow=better throttle response.
4) I don't think the underdrive pulleys are that good, unless you buy the whole set.
You can put in some pistons to increase compression, as well as change the MAF, if you can make it look stock. Good luck
05-16-2005, 02:49 PM
#10
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Join Date: Sep 2004
Location: knoxville tn
Posts: 999
the safc will also work on stock injectors... you can also get a stronger fuel pump and a nissan adjustable fuel pressure regulator... to get more fuel into the motor... and as far as the ecu goes... i looked for sohc ecu's with very little luck... jwt is said to be down 40 hp over other tuners on the dohc ecu... i dont know how good the sohc ecu is... but they at least make one... as far as changing anything on the motor... that has to bite... advance your timing... at least you will be running race fuel... and if you are running a race car then you already tossed the ac and all the stuff that goes with it... now toss the power steering and put an under drive pully on the crank and the alternator... if for some reason you are running an auto like me... there is a little ballast resistor on the drivers firewall by the coil... unplug that and it makes your auto tranny shift harder and stretches out the shift points... dont forget to remove your speed limiter... there are a bunch of writeups on how to do this...
05-17-2005, 08:47 AM
#11
The SOHC head has poor cfm flow rate numbers for a 2.4 litre you will want to port, hone, and extrude the mani, and head. A porting of .040 for the intake ports, and .060 for the exhaust ports..........
Also look for larger valves for the exhaust.
Look for exhaust valves in .040, or .060 enlargement.
Look for intake valves in .020 enlargement, or .040 enlargement
The SAFC is the biggest bang for your buck, and can be used with all stock OEM applications......
Fidanza aluminum flywheel works better than pulleys.
More weight is dropped from the stock flywheel than from pulleys.
Stock flywheel weighs almost 26lb.s, aluminum flywheel weighs 11.5 lb.s.......
Also look for larger valves for the exhaust.
Look for exhaust valves in .040, or .060 enlargement.
Look for intake valves in .020 enlargement, or .040 enlargement
The SAFC is the biggest bang for your buck, and can be used with all stock OEM applications......
Fidanza aluminum flywheel works better than pulleys.
More weight is dropped from the stock flywheel than from pulleys.
Stock flywheel weighs almost 26lb.s, aluminum flywheel weighs 11.5 lb.s.......
05-19-2005, 03:45 PM
#12
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Join Date: Jun 2004
Posts: 707
okay guys, i got stock specs from PDM-Racing for the SOHC:
Intake: 251*/.415 lift
Exhaust: 258*/.415
Are those specs correct? If so the Nismo and JWT cam isn't much diffent than stock:
Nissan Cam: 270*/.402"
JWT: Ex-256* In-248/ .422"
I was looking at PDM and they have a mild cam:
Intake:260*/ .424
Exhaust: 268*/ .441
Hybrid KA also has a cam:
Intake 270*/ .443" Lift
Exhaust 272*/ .448" Lift
But i'll have to get the cam tower milled .025" or run the solid lifters. Which cam do you think would be better for drift/canyon?
Intake: 251*/.415 lift
Exhaust: 258*/.415
Are those specs correct? If so the Nismo and JWT cam isn't much diffent than stock:
Nissan Cam: 270*/.402"
JWT: Ex-256* In-248/ .422"
I was looking at PDM and they have a mild cam:
Intake:260*/ .424
Exhaust: 268*/ .441
Hybrid KA also has a cam:
Intake 270*/ .443" Lift
Exhaust 272*/ .448" Lift
But i'll have to get the cam tower milled .025" or run the solid lifters. Which cam do you think would be better for drift/canyon?