Z32 Speed Sensor - Tech Support February 2010 - Super Street Magazine

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 What's up Super Street! I have read your magazine long before I even had a car, but enough of the brown nosing and down to business. I have a '96 Honda Civic with an H22A. I would like to do a nice shock/spring combo. However, I know that the H-series weigh more and need a stiffer spring rate. What can I get that will lower it to a good stance and improve handling?
Brent W.
Albuquerque, NM

A This is a great question. Most people that have done swaps don't keep in mind the added weight to the front end. This is really important when you start tracking your car. The best thing to do is get a set of coilovers and have the car corner weighed. Most coilover companies allow you to order specific spring rates too, so you can choose whatever you're comfortable with. If you can't afford a full body coilover, Ground Control's kits are a popular alternative. You can easily order Eibach springs in different rates from them as well.

Q I just bought a 1990 300ZX non-turbo automatic. Problem one: the speedometer doesn't work. The speedometer is stuck on zero and doesn't move at all. Where do I begin? The cruise control doesn't work either. I'm guessing this works with the speedometer. Problem two: the transmission shifts up and down between 75-80 mph, if I let off the gas just a little. Could this be the throttle-body sensor? It shifts a lot between 78-80. The tach goes from 3.5k to 4k. Is this normal?
David Miller
Emporia, KS

A On Z32s the speed sensor in the transmission is a common failure item. Just be sure to get the NA one. The turbo speed sensor is different. Speedometers do go out on these cars as well, but it's not as common. Cruise control is dependent on the speed signal, and so this is the root of that problem as well. The shifts with the transmission may be related to the speed sensor too, but if it still persists after a new speed sensor, then you might need a transmission rebuild. Consult with a transmission specialist after the speed sensor fix.

Q Hello there, you have an awesome magazine, best by far. Best in-depth detail on comparing the difference between B16 and B18 motors. Now I have one question for you that hopefully you guys can answer for me. I have 1990 Honda Prelude but not with the B21 motor, I've got the B20A9. I want to make a Frankenstein B20 VTEC. Can I use this block or do I have to use the B20 out of a CR-V? Also can you guys give me any idea of what kind of piston size is in there? And one last question sorry I know this is very winded, if I were to buy forged pistons for the B20A would it be the same as a B20 from a CR-V? Thanks for all your help.
D. Bullock
Moreno Valley, CA

A People have managed to put a VTEC head on the B20A but it requires so much work that it's almost not worth the time and money. It is not as easy as doing a VTEC head on B20B (CRV motor). As far as pistons go, they aren't the same as the B20B. Your B20A has a 81mm bore, while the B20B has a 84mm bore. If you want to use all of those aftermarket B-series parts, Innovative has mounts for the '86-89 Accord, and that kit may work in your Prelude. Check with them for an answer, www.innovativemounts.com

Q Your mag is the best. I'm thinking about putting a D16Y8 intake manifold on my D16Y7 engine. Will I need to change anything? Also is it possible to port the intake manifold to deliver more air? I'm also planning to put on a 74mm throttle-body. Any info will help. Thanks.
Wong Tong
Via the Internet

A Well, Wong Tong, although the Y8 intake manifold will bolt onto the Y7 head, you will need to block off the IACV and swap your Y7 throttle pulley and spring over. But if you find a Y8 manifold from an automatic, everything should swap over just fine. A 74mm won't be necessary unless you're making a lot of power. You might want to look into a B18B throttle-body.

Q I am running an '08 WRX and installed an exhaust and a K&N cold-air-intake. Being a member of www.3gwrx.com I posted the question asking if this is safe to run on my ride without a professional tune. The answers vary from Subie mechanics to forum members both saying yes and no. I have forum members kicking and screaming on the merits of both. I have taken the time to read articles telling in some other buster magazines that have followed the same installs. I get that a tune would really make it shine, but I want to know if I don't tune it, will it be disastrous?
Bill
Tacoma, WA

A You have to be careful what you read on online forums. There is tons of great information and members online, but there are also a percentage of members that just regurgitate hearsay, and want to get their trolling two cents in. With exhaust and intake you will not need to tune your car. Yes, it would be optimum to dyno tune your car, but it is not necessary with those minor upgrades. There is a small chance of running the car lean, but even still with just an exhaust and intake we would suggest saving the money.

Q Just wanted to let you know the October '09 issue was GREAT! I have a '94 Civic, which according to your Building Blocks is 'Mild'. I'm about to step it up to 'Medium' and wanted to know is there a better transmission I could use with my D16? The stock one tends to be a little stubborn trying to bang second out of the hole some days.
Hunter Hollomon
Via the Internet

A Unfortunately there is no other OEM transmission that will bolt up to your D16 other than another D-series transmission. If second gear is starting to give you problems, you might want to try a different type of MTF. And if that doesn't help the problem, you're probably looking at a rebuild soon or finding another used transmission. There are plenty of upgrades you can do to your transmission if you plan to have it rebuilt, stronger gears, different gearsets, different final drives and limited slip differentials.