82 replies to this topic

[jsgprod]

I don't recall for sure, but I don't think the D16A1 intake bolts to the Si head. Regardless, I don't think that would be much different than the Si intake that I already have. I'll do some cutting and fitting. At least that I can do indoors!

The D16 intake will definitely not bolt up to the Si head and the intake runners are noticeably larger than the Si's also, FWIW.

[zakats]

I did take some time to disassemble and clean the cylinder head. It looks very good, which is what I had expected. Maybe I can mock up the head, intake, and carb combo to confirm the fit. I also thought I could try hacking the FI intake manifold first, since the CDM carb intake is more rare. I recall someone else doing that, but it seemed like the fit wasn't as good. I'd like to check flow differences, too.

I took a couple minutes to put most of this together- really I listened to that song techno song "satisfaction" and then hank williams "hey good lookin" so these are by all means, rough and approximate.


Heres an idea of what you'd be looking at cutting: [red lines and blobs are cut away material]

I find it best to keep as much aluminum intake runner length as possible. The SI manifold, as you can see will be much more work.. but coming from me as I need a cdm IM, please don't kill it but do what you have to.
the injector rail 'bolts' will have to be cut down.
the injector holes will need to be filled OR
...you can connect them in a variety of ways.

brown lines represent metal piping then connected to probably large low press fuel hose, injector holes would most likely be tapped with a hardware store available pipe tap as well as the pipe [depending on setup, the use of t's and 90 deg elbows would be recommended rather than bending the fuel hose]

the black rectangles I drew are valves to on/off the flow between the diff runner setups. the valves should be electric and available from the uber electronic guru store (need to pay them a visit because they have sooo many cool little useful trinkets in hobby building!) they could be switched automatically via rpm signal like the typical shift light hack w/relay or vacuum switch w/relay.

why? the same concept of typical carburetor "secondaries" applies, yeah it might only be a small amount (can be opened up for more flow!) of extra flow but that can make a lot of difference- allow the use of smaller carburetors for better fuel economy and drive ability, and better top end.

if your carburetors are big enough [in the case of my cbr carbs on my EW1, maybe a bit oversized] then it might not really make any difference; but with a setup like in my "new" engine with the bike carbs being a little under sized, I believe it will make a difference- what a/f the "secondary" tubing will be sampling is another question yet to be answered.
maybe I should make a thread about this?
-zak

[squareback]

The D16 intake will definitely not bolt up to the Si head and the intake runners are noticeably larger than the Si's also, FWIW.

That's what I thought about the fit, and larger runners are not what I want either.

Zak-- I'll try the Si manifold first since they are more common, and I can always do the CDM intake later if I'm not happy with the first one. On that subject, if I am happy with the cut up FI intake, I probably wouldn't need the CDM one anymore. If you'd be interested, you can have dibs.

Thanks for the drawing. That's just what I have in mind. I'm hoping to find time to start this weekend.

[zakats]

I might take you up on that...

[87crxdx]

hey, i've always wanted to do a devac but on a USDM car it looks a lot harder then the CDM version. what would you rate the job out of 10? and which thread did you use for the how-to? I remember Eldo had a good post on it.

[zakats]

hey, i've always wanted to do a devac but on a USDM car it looks a lot harder then the CDM version. what would you rate the job out of 10? and which thread did you use for the how-to? I remember Eldo had a good post on it.

briefly straying off topic; do you have a usdm car for some reason? it isn't difficult really- it involves removing the black boxes, a massive amount of vacuum tubing and associated brackets- etc- its all removal and moving around of stuff you already have (other than the vacuum caps) the only down side is the issue of air conditioner idle boost, if you have a/c you will need to fabricate something to boost the idle when you have the a/c on... not really a big deal, I did just fine this summer with just keeping my idle at 1000-1200 ish
also there is the problem of the head having cvcc, the cdm cars dont have cvcc so you don't have to worry about any of that.
search is your friend, if you have more questions refer to the "TECHNICAL" section, sub-section "CARBS"

-zak

[squareback]

Update today. Due to whatever sickness I've had the past few days, I have no voice right now. My body is a bit weak, but overall I'm feeling better. Since my job requires a great deal of talking, I'm pretty useless right now. So I stayed home today and did a couple of things and snapped some pictures.

I did the first stage of intake hacking on the Si manifold:



The next step will be to cut off those fuel rail bolts (and all the material under them) and shorten the runners.

Here's a couple pics of the carbs:





Notice that the float bowls sit at a slight angle. The engine sits in the car at a similar angle, so the bowls should be level when installed parallel to the engine. This was one of the main reasons I went with these carbs. Also, they are 36mm, which I think will be perfect for the plans I have for this engine.

And here's the parts laid out together:



It's difficult to tell from the angle of the photo, but the middle two carbs line up perfectly with the intake ports, and the two outboard carbs are about 3/8" wider than the outer intake ports. Once I get the manifold cut down to the proper length, it shouldn't take much work to get everything clamped together. I hope to find time this weekend to finish the manifold.

[squareback]

Update--

I tried to get the title a couple weeks ago, but they said I needed an inspection first. So I went to get the inspection done this week (dragging the car there on my trailer), and when I got there, they said I couldn't get an inspection without a title. So wait... what you're saying is I can't get a title without an inspection, but I need a title in order to get an inspection? Um, yeah. I got upset. After basically telling the highway patrol inspector where she could shove it, she says she can try another route. She calls her supervisor at another location and explains the situation. He wants me to come over there so he can try to figure out what to do. At this point, I'm just so tired of all the runaround that I agree to go to his location across town. I'm glad I did. He turned out to be a reasonable and nice guy, and he asked me to explain the whole story of this car from start to finish, which I did. When I finished, he said all I needed was this inspection and then sending in to the state for a duplicate since I had all the necessary paperwork otherwise. When we went out to the car to do the inspection, he even commented how nice it looked and asked for a little info on the 3G cars. Neat. SO . . . I got the inspection and sent in for the duplicate title, which should be back by Wednesday. At that point, I should just have to use the power of attorney to have the title company assign the title to me and send it back to the state to issue a new title in my name. Sheesh.

Since I had the car out, I snapped some pictures in its current state:





I also did a bit more work on the Si intake that will hold the bike carbs. It's nowhere near completed, but it's getting closer. I still need to cut down the outer runners a bit so they don't turn inward so much, and everything needs to be ground smooth. The injector holes need to be filled as well. Here's what it looks like now:



We finally have decent weather here, so I hope to complete a lot more work soon. This weekend will be tight since I have an autocross on Sunday, but I'll do what I can.

[censurebush]

damn nice lookin' ride! i'd be a proud 3g owner with that shell.

[mep]

Awesome project Mike. That's a heck of a find, & when it's finished it will be so very worth all of the title hassle.

I would only offer one suggestion to the final project... some really cool old 13" wheels!! The RPF1s are nice of course, but the car will be so rare & unlike anything else driving around, that some old Enkeis or Panasports, etc would make it that much more unique. But you know how I am about my wheels

Regardless, the car is so mint & I'm looking forward to more progress.

Mitchell

[squareback]

I would LOVE to do 13" old school wheels, but there aren't many choices in nice 13" rubber. I haven't given up on it.

I have a picture from Grassroots Motorsports magazine that was in an issue from 2002, I think. It was a history of the Civic Si and featured the 1500S, which the publisher made a clone of back in the 90s. The picture shows this 1500S clone with some 13x7 Panasports that look so sweet on the car. That picture is what convinced me that long ago that I would have to find one of the 1500S cars someday. I wish I could scan the photo to show here. Of course, back then you could get decent street tires in a 13" size.

BTW, that article is scanned in CRXfanatic's gallery here on RPR. It's the article called Dual Hondas.

Mike

[Louis]

Loving the build up of this 1500S

Ive got one too!


Although i think i might prefer your paint scheme, plus its mint!

Looking forward to seeing how you get on with the carbs.

[squareback]

Update from yesterday. I had some time to finish the intake manifold to the point that I can continue the conversion. I didn't take the time to completely smooth and shape the outside of the runners since I didn't know if I'd be happy with the performance of the intake, so don't pay much attention to that. I did smooth the insides and cut the runners to the length I believe they need to be to make the carbs line up as well as possible. The only thing I haven't done is knife-edge the openings of the runners for smoother flow. The CDM intake runners would be a smother transition for the spacing of the bike carbs, but I'll try this first.





It's not the prettiest thing, but I think it will work to get me started. Next will be finding suitable hose to attach the carbs and intake together. I'm also going to try to get the car started this week with the stock intake and carb. I've been itching to drive this car, and with the titlework nearly done, I may be able to register the car within the next 2 weeks. I'd love to be able to drive it then also. The car started and ran okay back in November, but I've not tried to start it since then with all the other stuff I've been doing and the cold weather we've had. It did have some knocking when it ran, which I haven't diagnosed, but that's why I'm doing the engine swap also. I'll update after trying to start it in its current state.

[squareback]

No real updates. I have been doing some thinking about the wheels and tires for this car, and I really like the idea of staying with something appropriate for the era and the size of the car. With that in mind, I think I have decided to find some 13" wheels to use for the car. The problem will be finding a set that is the correct offset and width to allow me to still use the relatively soft springs I want to use, especially in the rear. Ideally, a set of 13x6 wheels with about a 35-40mm offset would be nice, and I'd like to run about a 205/60 tire. There's the other problem, as nobody makes a really nice street tire in a 13" size. The Sumitomo HTR 200 is a nice all season tire, but I'd like something with better grip. I had a set of 215/50 HTR 200 tires on OEM 13x5 steelies that were fine for everyday driving, but they lacked the grip I like when the road turned twisty. I'll give this more thought, but I think I have settled on the 13" for their looks with the rest of the car.

Hey, if you're reading this and have a set of 13" wheels you're itching to get rid of, let me know!

[zakats]

diamond's... your preferences really throw most of the conventional options out the window- also I'd reconsider 14"s for tire options