Tech Support September 2009 - Nissan 240SX Transmission Swap - Super Street Magazine

Where We Cure All Your Tech Problems
Here's where we act like we know something technical about cars. Feel free to ask us about your technical troubles. Write us at tech superstreetonline.com or Super Street c/o Tech Support, 6420 Wilshire Blvd., Los Angeles, CA 90048. Feel free to include a picture of your project or tech problem.

Q Hi, first I just want to say the mag rocks! So I have a '96 Toyota Corolla with a 20 valve 4A-GE blacktop. It idles high and boggs or misfires every now and then and idles around 1200 rpm. The only mods on the car are filters on the ITBs, an HKS header, Splitfire sparkplug wires, Iridium plugs, 2 1/4" exhaust and the JDM ecu. Sometimes there is black gunk that comes out of the exhaust when idling. Someone told me that it's running rich. How do I get it running correctly? Just like everyone I'm on a budget and I've been working on the car for eight years now. Any advice would help!
Ryan Olea
Via the Internet

A Troubleshooting a car with diagnostic equipment and the car in front of you can be a challenge, so you can imagine what it's like trying to do this solely based on information in an email. For starters, we'd recommend that you get a hold of an AE111 factory service manual (FSM), which can be downloaded off the internet pretty much everywhere. Next, check the basics such as fuel pressure, ignition timing and ECU codes (the AE111 Black Top ECU is smart and might be trying fix an intermittent problem). You might also try resetting the ECU to see if anything changes. Since you're running ITB's (individual throttle bodies), two key sensors that should be checked are the MAP (manifold absolute pressure) and TPS (throttle position sensor). After checking that your MAP sensor is working properly (per FSM), what you want to do is make sure that it's getting a solid vacuum signal from each cylinder. To do this properly, an external vacuum manifold should be used to even out the pulses from each cylinder. Next, to check the TPS, measure the voltage from idle all the way to WOT (wide-open throttle) and compare your readings to the specs listed in the FSM. Lastly, check for any vacuum leaks between the throttle butterflies and the valves. A vacuum leak in this area could easily throw off your air fuel mixture and idle. A trick to check for leaks is to block off the ISCV to see if it stalls the engine. Another trick is to spray carb cleaner around the throttle-bodies and the manifold while the engine is idling. If there's a leak, the carb cleaner will seal it for a second and lower the idle speed. If the idle screw has been messed with, reset it to FSM (factory service manual) specs. Unfortunately, we cannot cover everything in a tech email. Use the factory service manual to guide you the rest of the way. As another reference, check out the Club4AG Technical Forums. They have one dedicated to the AE111 20V Black Top motor: http://forums.club4ag.com/zeroforum?id=13. As for measuring if your engine is running rich or lean, don't rely on your friend's nose. The only way to accurately measure the mixture is to install a wide band AFR meter. If you plan to do any kind of tuning on your own, be sure to pick one up.

Q I have a '92 Nissan 240SX with an automatic transmission. I was wondering if any company has created an auto-to-manual transmission kit? The reason I ask is because I want to stay with the somewhat stout KA24DE and replace the transmission to a manual. I will be purchasing a rebuilt KA24DE within the year and figured I should just try and do it all at once.
Michael Gomez
Via the Internet

Q Hey Super Street, I've read articles on 240SX's and their problems and thought it was kinda funny how such an awesome car could have so many. So, to test out my theory that it isn't hard to tune one, I'm asking a question regarding my 240SX hatchback. It has a 2.4L KA24DE DOHC and four speed automatic transmission. It is absolute fun-ass to drive and I still love the car. Problem is that the car only has four speeds. My question is if there is a way to get more gears on the car, or even better, a cheap way to get an automatic to manual transmission swap? Can you give me any ideas as to if or where this is possible? Thanks for the great mag.
Steve Manzo
North Olmsted, OH

Q I have a question that I can't get anybody to answer so maybe you guys can help me out. I'm swapping a manual trans into my 240SX. My 240 is a '91 and the trans is from an S14. So will it work in my car? I know I'll need a new speed sensor and I know there is a difference between ABS and non-ABS drive shafts (I can't find one in my price range for the life of me). Other than that, what am I gonna have to do to make it work? Wiring mods? Do I really need a dust shield? Will the S14 bell housing work on a S13? If you can help me I'd really appreciate it, love the mag.

P.S. Keep up the good work. I've never seen better in coverage, car, girls or race days. Cheers.
Nicolas Arias Denardo
Via the Internet

A Well guys, this is your lucky day. We just covered the auto-to-manual conversion in the January/February issue of our sister publication, Project Car magazine. Project Car is a sister magazine of ours that spawned from Super Street. Its focus is on showing the readers how to modify their car in a step-by-step DIY manner. So go to www.primediabackissues.com and order your copy before it sells out. It's the one with a budget-built S13 coupe drifter on the cover.

So to answer your questions, the easy way to swap from auto to five-speed is with used junkyard parts. You can use either an S13 or an S14 transmission in an S13. The bellhousings are the same with the exception of the S14 having a hole for a crank angle sensor at the top of the bellhousing. Other differences are the speed sensors, but you can drop a five speed S13 speed sensor into an S14 transmission to correct the speedo gearing. As for the driveshaft, you'll need a non-ABS five-speed driveshaft if your car doesn't have ABS or an ABS driveshaft if your car has ABS. S13 and S14 driveshafts are different, so get the correct one for your car. There are several other parts needed for the swap which are all covered in detail in the Project Car tech article. As for wiring mods, it involves rewiring the neutral switch, reverse switch, speed sensor, and bypassing the neutral safety circuit. It's actually much easier than it sounds and is also covered in a step-by-step manner in the same article. So get rid of that power robbing auto and transform your wannabe Silvia/180SX into the spirited drifter that it was meant to be.

Q Your mag is like how Paris Hilton says, " that's HOT." I have this project I am working on, it is a 1996 Nissan 200SX B14. I was wondering what was the best engine to drop in it without changing the motor mounts. I was thinking the SR20VE. Is there a bigger engine that will still fit the motor mounts and that could still utilize the VVL tech.
Jorge Cruz
Via the Internet

A If you want variable valve lift and timing (VVL), Nissan's version of VTEC and you want a drop in swap, your options are the SR16VE (173HP) or the SR20VE(187HP). Some of the less common versions of the engine are the race tuned SR16VE N1 (197HP), the later SR20VE "20 V" (204 HP) and the AWD turbo SR20VET (276HP). As far as we know, the largest displacement for this engine family was the 2.0 liter. For more info on this swap, check out the Spring '09 issue of Project Car magazine. We dropped an SR20VE into an Infiniti G20 (P10 chassis) and ran it against an LS/VTEC powered Honda Civic (EG chassis). The final results will surprise you. Copies of this are also available from www.primediabackissues.com.