need answer soon pweeze b20a-b21 - Honda Prelude Forum

PreludeTuner23 · 03-18-2004, 08:21 PM

I'm swapping a B20a into a Prelude that originally had a b21 a 90si. The car is an automatic and I live in Ohio (no emmissions). Do I leave on JDM intake/exhaust manifold and go without EGR??? Or do I swap them over from the B21??? The other thing to consider is the JDM's dual stage intake manifold runner/butterfly valve thing. Performance is not an issue this is going to be my work car. What is the consisous on this?? Swapping over the 2 manifolds will tack on an extra $100 to a project that has already been very costly. Is it going to hurt performance/reliability in anyway to leave on the JDM manifolds. If not, what should I have the mechanic do about the second runner on the intake manifold and the EGR not being there??? Thank You a ton for any help and please be as specific as you can as I'm going to send this to the guy doing the swap.

fleshbox · 03-19-2004, 10:42 AM

where did you find the motor btw? and how much was it shipped?

lightlude · 03-19-2004, 11:02 AM

I don't think anyone is going to be able to answer the emmissions question for you (I presume you have to pass some sort of emissions?). So no one is gonna be able to tell you if you really need the egr of not.

Don't worry about the dual runner thing though. It really shouldn't affect emissions (at least not as much as the egr would). So you can leave the manifold on as far as the dual stage is concerned. It might run a little rough if you use a ecu that doesn't recognize the 2 stage though. But the 2 stage doesn't work on my car, and it runs just fine, so draw your own conclusions from that.

PreludeTuner23 · 03-19-2004, 06:04 PM

no, im not worried about emissions just about reliability and how the ECU will react. Thanks

Daily Interlude · 03-23-2004, 01:30 PM

Car will be fine w/o an EGR. It may not even through a code. You can just leave the second runner disconnected and it will act like the B21 manifold.

The only thing negative about any of it is that there maybe an annoying Check Engine light.

JohnnyTequila · 03-23-2004, 06:46 PM

reliability will be fine wihtout EGR, your gas mileage will go down, and that annoying CEL but thats about it. you can use the stock ECU from the car.

PreludeChick89 · 03-23-2004, 06:48 PM

i left everything jdm... it only says the o2 sensor and something else.. otherwise she's working just okie dokie... for that annoying CEL.. take apart the cluster and just pull the bulb out b/c you won't pass inspection if you bring the car in with the CEL light on... once a month i check under the carpet to make sure nothing new is comming up just in case..... then again i have a b20a5 ECU but i doubt it would be much different...
the gas mileage isn't too bad.. i average 23-28 depending on my driving.. i am also automatic.....