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I'm planning on building a D16A6 or a Y7 for my '95 Civic hatch.. all motor.. headwork.. fun cam... probably on a near-stock block. My powergoals are minimal, only looking for around 160whp -- this car will be used for Solo2 competition -- not drag. I plan on daily driving the car, though i've already thought through fuel economy problems. Driveability isn't a big issue as I have dyno access for tuning and the time to warm up my car in the morning
I'm still researching carb sizing (hopefully bisi will help with that) and such.
I just have a few basic questions.. and believe me I searched. Maybe I just suck at searching but feel free to make me look stupid with a helpful link or ten.
1) What manifold to use? Custom stuff isn't really what I'm looking for. Is there an off-the-shelf manifold or a random OEM Honda one that I could use?
2) Since you don't really need an ECU... do you still use on for other functions? (gauge cluster,e tc.) Since the car is OBD, will this prove a difficult conversion? I read about vacuum-driven distributors and such.. can someone explain?
3) Where do all the wires/lines go? Such as the plug for the MAP sensor? Should I get a vacuum manifodl for the brake booster and such?
You could look for the TWM manifold which was a DCOE style intake manifold. I don't know if they make them anymore but you can find them used.
You don't need the ECU for anything. I custom wired the whole car and used an Electromotive XDI DIS which lets you junk the distributor and is a powerful setup but it requires a 60 tooth crank gear be machined onto your crank pulley and something fabbed to hold the magnetic sensor at the correct position, worth it in the long run IMO. Even if you use a stock gutted dist. you don't need the ecu. I know some people run a stock ECU which has to be physically advanced by slotting the dist holes and from what I hear works pretty well, but by just doing that you will have fixed timing which is far from ideal at low rpm. MSD makes timing computers that let you have a "curve" with your stock, gutted distributors.
In my experience the power brakes work fine tapping off one runner on the manifold.
Make sure you size the carbs correctly and get something that has easily purchased parts and jets like a Weber DCOE. The carb sizing is dictated by the choke (main venturi) that you think would be ideal for your setup. 160 whp is going to want at least a 37-38mm choke which would require a minimum of Mikuni 44 or DCOE 45 carb.
Its not that easy to get 160 whp on a stock displacement d16 although the carbs help alot in that department. It usually will require a pretty good flowing head, some compression and an aggressive cam.
Also, if you want to get technical with the tuning--you can spend days, weeks--years!! to get the Webers running to perfection. It isn't too difficult to jet for peak power and high rpm but I don't care what anyone says--its not "simple" to optimally jet for low rpm --fuel injection like driveability. The Webers have the advantage there because there are literally like 40-50 DCOe emulsion tubes available while the Mikunis only have a few if I am not mistaken.
Also, the Dell'orto DHLA has a smoother progression than pretty much any side (certain models of the DHLA more than others, some have up to 6 progression holes--that is alot!!) draft, but like the Mikunis they require their own jets, chokes and e-tubes which are available but are alot more difficult to track down if its Thursday and you need a particular jet by the weekend.
Certain DCOEs (ie the 40 DCOE 151 and 45 152) have a 3 hole progression but the first hole is in the absolute wrong place for a high strung small displacement 4 cyl motor with low vacuum. What this does is creates a dead lean spot just above idle--very noticeable if you are parking, not so noticeable on the road although if you are in neutral and rev the motor to 1500-2000 rpm and hold it, the AFR will go off the chart lean and the car will sputter if you do not "fix" it. Also, if you were trying to drive stock 151s or 152s in bumper to bumper traffic, that little lean "hole" will drive you nuts. The fix is rather easy in theory but really should be done very precisely for optimum results--accurately drill a fourth hole directly above each throttle plate when the plates are sitting to give a 900-1000 rpm idle (factory dictated idle speed for most DCOE carbs).
There is a DCOE called the 45 152 "G" which has the fourth hole already drilled from the factory, harder to find but ideal for 1500-1800cc Honda. The G stands for German or Germany--supposedly because German tuners had terrible hiccups trying to use the stock 45 152 on 1600-1800cc water cooled VWs with large cams and low idle vacuum. The G has four progression holes which are in the correct place to give a very smooth idle to main transition with no hiccups even on a high strung 4-cyl motor.
there are not many who know carbs but man once you master carbs you are a SAINT to many... i was raised with nothing but DCOE's all day.. my father can syc carbs by year to drive like a stock car!!!
and the sound. MANNNNN it will give any man a WOODY by the sound!
There are also others you may come across--the old SK Racing, which actually use DCOE jets, chokes, and e-tubes and the (newer) OER 45 or 47 which I think also might use stock DCOE jets.
If you are going to be runnig a sidedraft setup you MUST get the factory Weber tuning manual. Even some of the info in the Weber tuning manual is incorrect but its LOADS better than 90% of the books written to "help" sidedraft users.
Many of the people who wrote the older DCOE tuning books--from the 80s and 90s were wrong in alot of their assumptions of what was actually happening inside the carb at speed. Now that low-cost and accurate AFR tuning is available its alot easier to try to get the information that will help you.
Drew up the flange in solidworks and had it 3d printed in SLA from a friend of ours . . . close but not perfect yet.
I'm in the same boat so to speak. We've got a $400 stripped out crx so emissions is no longer a concern and it doesn't have any wiring or ECU so really a carb makes perfect sense.
05-09-2007, 11:43 PM
D-series carburator manifolds
