Just that - I'm wondering what an appropriate size intake diameter would be for my 93 Civic EX - I believe that's a 1.6l with a 56mm tb.

 

2.5-3". Really doesn't matter if they are the same size, or larger than the TB since that (TB) would be the most restrictive part of the set-up.

 

Being fairly new to the Japanese market, and hence, the subtle nuances of my Honda's motor, I don't even know of this is OBD1 or OBD2 - which I'm sure has something to do with the location, not to mention, the potential existence of a MAF sensor. That said, if it does exist, and were it in the intake tract pre-TB, wouldn't the diameter of the intake have a potentially important impact on fuel trim and such?

 

OBD1

No MAF.

Honda runs off a MAP sensor, located directly on top of the TB.

No matter what, the "massive" amount of air in say, a 3.5" intake will not go into your motor any faster since it all has to funnel through a 56mm TB.

 

Oh, I see.
So is that to say that the TB is the bottleneck on the intake end of things? Beyond that, what's to be had? Larger TB? Intake runner gasket-matching?
I don't mean to go off topic, but is 'chipping' this vehicle possible?
Thanks!

 

Yes, you can chip the ECU. I don't recommend you doing it unless you either have a spare ecu on the side, or you know what you are doing.

If you bought a 3" pipe, the next restriction would the the TB, then the opening on the intake manifold where it meets the TB. You would be looking to remove the manifold, bore the hole out to match the new TB (maybe 60mm would be good for you), then reinstall everything. If you do that, you need to replace the intake manifold gasket. Pick up a gasket from hondata (basically a piece of plastic). Much better than the paper gaskets from honda. May cost a little more, though.

 

Excellent.
I suppose my next question should be: are there any gains to be had by modifying the intake, before the exhaust?
Also, the ECU is located on the right side of the passenger-side footwell, yes?
Having not looked at anything up close, would the TB mod be something that I can do to a stock TB, or is this a strictly aftermarket part?
..and as for the gasket matching, I was thinking of doing that on the head-side of the manifold, not the TB-side - I wasn't aware that there would be a need for the gasket matching between the TB and the manifold - good to know.
Thanks again.

 

Come to think of it, is there a bolt on application at 60mm from another Honda? I noticed that there were a few 60mm throttle bodies in the OEM TB Sizes faq - a few B & F, as-well-as an H series. I don't know what year or model they would be found upon, but I'm going to the boneyard this weekend for some body panels..

 

intake, before the exhaust? What? You have an intake system, the motor, then the exhaust system. ALL of the intake system is before the exhaust system.

Yes for the ECU.

The TB would be a replacement part, not something you do to your current unit.

Probably no reason to port the intake manifold runners if you are not porting the head. Again, you are making the IM runners bigger, but I am assuming the holes in the motor will stay the same, providing almost zero benefit.

All D/B/H/F TB's are interchangeable. Go with a 60mm TB from a LS (b18b1) Integra. You will not have any problems with that and they are relatively cheap if you are looking for a minor upgrade.

 

I really appreciate all of your input - I'm certain you'll be saving me time and at least one headache!
I think, however, that there might have been a bit of a misunderstanding. Though this is my first Japanese vehicle, I was operating under the assumption that yes, the order of operations was intake, motor, exhaust. What I was implying was - would it be best to work on the intake side of the motor before the exhaust, in order to achieve maximum benefit? If there was a significant bottleneck somewhere in the exhaust, I would think that I would be better off focusing on that up before I put time into the intake.
Thanks again - I'll keep my eyes peeled for an Integra corpse.