I had my b20z swap in my 90 integra for about year now and my one of my buddies is selling his b18b1 intake manifold with tb from his 96 intgra ls for baically dirt cheap. Currently I used the b18a1 intake manifold with tb on b20z. So my question is it worth the upgrade? Is it a direct swap?
I cant answer all your questions but i can shed some light on afew things for ya.
Apparently the P75 (b18b1) is slightly better than the PR4 (b18a1) intake … ive got both sitting here right in front of me and the only differences i can see is that there is a port on the front of the manifold for the FPR instead of the back, and that there is only one coolant pipe instead of 2 like the b18a1 intake. Ill post a pic if you want. But basically, it will bolt straight on without a problem, just have to do something with the coolant lines i think.
Im not sure what the coolant lines are like on the b20 block, but on my B18a1, if i want to run the b18b1 intake (p75) i have to figure out what to do about the coolant lines… im gonna start another thread hoping someone has already worked it all out…
Hope it made some sence!
Let me know if you want a pic to help understand what im talking about! lol
Oh , and the b1 throttle body is 60mm with the map sensor attached to it, while the a1 throttle body is 58mm with a seperate map sensor (ususally on the firewall)
Thanks for responding! If you can upload the pic I greatly appreciate it. I’m gonaa bite the bullet and pick it up. I’m gonna port match it to the gasket before I install it.
After alot of googling and looking at diagrams ive figured out how to run my coolant lines, the b18a1 has 1 extra coolant port on the thermostat housing that i have to block off, on the b18b1 its already welded up.
Ignore the black paint, but this is a standard b18a1 IM… ive circled the ports i was talking about. The left circle is your fpr and purge solenoid ports. And bottom right hand corner are the two coolant ports.
And this is the B18b1 IM , notice only 1 port for the purge solenoid (the fpr post is now at the front) , and only 1 coolant port down the bottom right.
Pretty simple really, oh and theres no FITV mounted on the B1 intake either… if your still running one, just delete it!
Hope it helps!
Well I didn’t get the the intake manifold afterall. I didn’t feel like driving 60 miles for it. So I might do the fit delete if I’m not lazy or have some free time during this weekend.
You didnt miss out on much i think, looking at them side by side (and afew articles on the net) i doubt theres much difference between the two.
Only reason i ended up with one is cuz it came with the throttle body, which is 60mm instead of 58mm… yep a whole 2mm bigger! lol
Actually, how are you liking the b20? Decent improvement over the b18? I think im going to be needing to refresh my bottom end soon (piston rings and main bearings), and im tossing up between upping the compression with a set of p30 or pr3 pistons… or sourcing a b20 bottom end. Decisions, decisions!
[QUOTE=Denied;2321833]…60mm instead of 58mm… yep a whole 2mm bigger! lol…[/QUOTE]to most people myself included, 2mm is pretty much irrelevant, but not if you are racing the car in a class with essentially identical (same displacement) engines. Air flow is roughly a function of the area, so more-or-less proportional to the square of the radius. pi*r^2
So, about 26.4 cm^2, compared to 28.3 cm^2, or 7% difference. Unfortunately, unless you have a “tuned” ecu, you probably can’t take advantage of this at all… 
[QUOTE=Denied;2321833]You didnt miss out on much i think, looking at them side by side (and afew articles on the net) i doubt theres much difference between the two.
Only reason i ended up with one is cuz it came with the throttle body, which is 60mm instead of 58mm… yep a whole 2mm bigger! lol
Actually, how are you liking the b20? Decent improvement over the b18? I think im going to be needing to refresh my bottom end soon (piston rings and main bearings), and im tossing up between upping the compression with a set of p30 or pr3 pistons… or sourcing a b20 bottom end. Decisions, decisions![/QUOTE]
I can’t compare the b20 and the b18 motor. The original b18 that came with the car had no compression at all. So I swapped it for a b20. At that time I needed a car running for work. I can tell you this much about b20 is that I can overtake cars in breeze at highway or city driving. After passing 80mph is when I feel my top end has reach the limit lol.