i just bought a 91 integra gs 5 speed with a b16 swap, he said it was out of a honda integra xsi, im not new to integras but im new to b16 integras so i need to know what intake, header, etc, to use, since it is a b16 i dont know if i get an integra intake, header, or what. sorry if you dont know what i mean. the swap is clean and it runs really strong he had all paper work for the motor installed 3 months ago, i think i got a good deal at 2300 but i want to upgrade everything and i need some direction towards what parts. any help is great, oh i think he said it is obd0 if that matters, and on the block it just says b16 not a or a1 or a2. thanks. i also have a b18 aftermarket crank pully will that fit on the b16?
As far as the motor goes! If its out of the Xsi then its OBD1. I’m guessing since he told you it was an OBD0 its prob the 1st gen JDM B16 (88-91). As far as headers go, you want to purchase a 90-91 Integra header and it will bolt right up. Same goes for the intake!
thanks, how do i find out wich ecu it is so that way i can know. also the guage cluster is gsr so it goes to 9k or so what is a good shift point, it feels like it makes power al the way to 8200 but i dont like to take it that high if its not doing any good, also what is a good launching point for that motor
pull back the carpeting in the passenger side foot well and look at the ecu. It’ll have the code on it…you might want to shift at about 4-4.5k rpms…I usually always shift at about 3-3.5k, but I don’t drive hard all the time, ya know? If you wanna play a little with vtec, you know what you must do…rev it up 
The ecu is located on the floor on the passenger area! The ecu should be a (PR3,PWO) if it came with the motor. There should be a sticker on the side of the ECU that will give you this info. Redline is 8000k for the OBD0 B16 and 8200K for the B16A OBD1. Vtec kicks in at 4400K on OBD0 and 5500K on OBD1.
This isn’t true.
XSi Integras were made in both 89-90 (OBD0) and 91-92 (OBD1). The OP’s engine can be an OBD0 XSi B16A.
Since your B16A is OBD0, you will have issues with aftermarket headers. OBD0 VTEC engines used two unheated, single wire o2 sensors; one for each 4-2 merge in the exhaust manifold. You will have to get a 90-91 header and have two o2 bungs welded in at the merges to have the car run correctly with OBD0.
If you take the stock heat shield off of your exhaust manifold you will see what I’m talking about. Using a 4-2-1 header would make this process easier, but there are people that have used 4-1 headers on OBD0 VTEC cars.
Here is a pic of a 4-1 header with the two o2 bungs installed on the primaries:
Here is some more info from an old site that was one of my favorites: http://lyonel.orcon.net.nz/jdm4-1_install.htm
That site is a great G2 resource 
also on my transmission i saw s1, is that the transmission that normally comes with that motor, he said it was short geared but first gear in this car goes to about 35-40 mph and my old integra with a b18 only did like 30-33, but when im at 60mph in the b16 im at 3.5k and in the b18 i was at 3.5 at 70, anything you guys know about my motor and tranny would help me alot, i plan on big upgrades and i dont want to buy eveything twice cause i got the wrong one, sorry if i sound like an idiot but i dont know b16 very much.
i just looked at my ecu and im sure it says pr4-003, im not that sure cause after i looked then came in my computer room i already forgot, but i had to remove the ecu gaurd then lift the ecu out to see that, it was the only letters i found. does pr4-003 ring a bell?
That’s no good if it’s a PR4. A PR4 is a non-VTEC LS/RS/GS ECU.
…You might want to go back and check again. Your ECU should be a PR3 if the engine came from an Integra XSi, or a PW0 if your B16A happened to be from a Civic/CR-X SiR.
sorry, just double checked and its pr3-003 and a bunch of numbers before that. so how can i tell if its obdo or obd1? also do you know what the s1 on my tranny means, is it a good tranny for a little drag or road course? you had me scared about the ecu, i knew i should of wrote it down.