albayfz450

Ok so I got a 2000 si with an ITR swap. It has an intake, 2.5 inch piping with a vibrant muffler. And a chipped p28. The thing is that I ran short on funds and I am currently running it with a b16 exhaust manifold. I just wanted to know if that is holding me back a lot or not. Thanks

Arthas

I doubt its holding you back much, and if you dont have the funds then what you can you do about it?

albayfz450

that's true but I justwantedto know how much it was holding me back

nsxter

how are you running your b18c with a b16 exhaust manifold the deck heights are diff the b18 is to tall for a b16 header

albayfz450

It fits fine on my car with no problems

honda_luvr_2000

Nope. A header for a B16 will fit B16, B18C1, B18C5, LS-VTEC & CR-VTEC. I know for a fact, because I have a CR-VTEC with a B16 header. A very common swap (in the other direction) is to put an ITR knock-off on a B16.

Deetz

I'm surprised it clears too. I've had issues in the past testing B16 headers on B18 blocks, they didn't clear the oil pan

B18C5-EH2

+1

Are you running the upper manifold from the B16A with the 1.8L A pipe or something?

The actual MANIFOLD is interchangeable fitment wise, but the A pipes do not fit from the B16A onto the 1.8L engines due to block height differences.

B18C5-EH2

You are saying that as if it is factual information, and it is not.

A header built solely for a B16A will not clear the oil pan of a B18 block.

A header built for the 1.8L block will certainly fit on a B16A, albeit it does hang lower than a purpose-built B16A header due to the block height differences.

I think you got a header that "fits B16A" but is not made specifically for a B16A, and it happens to clear all 1.8L and B16A blocks.

Think about this:

If the B16A/B18C headers were in fact 100% interchangeable then why do header companies offer a header "for B16A" specifically?

albayfz450

So it's not really hurting my power with a stock b16 manifold?

93egSLEEPER

Oh really? Know your facts before you spread false info please.
B18C5-EH2 is 100% completely correct, and if you dont believe us buy a b16 specific header and try to put it on a b18 or b20

All the b-series manifolds are interchangable as stated above, it the "A" or "downpipe" portion thats different. If they are interchangable then they all are made with the same specs. Unless you plan on running a ITR header or something aftermarket dont worry about it.

albayfz450

So it's not? I'm confused. Lol. I just want to c if it's worth hurting and buying headers or not

B18C5-EH2

Any decent header should be an improvement over the cast iron manifold. When I say decent I'm not talking some Ebay special either. You can get one of those VTEC KiDD knock-off headers that have been proven to make good power, or get a DC JDM 4-1 or any good header with the 2.5'' collector.

You just have to make sure you get a corresponding 2.5'' cat converter (or test pipe if you have no emissions to adhere to) so you're not bottlenecking the flow from the nice 2.5'' collector down to 2.25'' or whatever the OE cat is.

For reference I made 175whp/122ft-lbs. of torque with my stock ITR manifold on my B18C5 with a preprogrammed chipped P28.

After installing the DC JDM 4-1 header and having the P28 rechipped/tuned on the dyno the B18C5 makes 179whp/131ft-lbs. of torque. Now I'm not citing those numbers to be compared to other set-ups necessarily, but more to show the effects of the header and tuning on my engine before and after. The header certainly helped, but the tune did too. It's hard to say what % was the header itself vs. how much was in the tune itself, but either way the header is the key to unlocking good power in the B series engines.

honda_luvr_2000

B18C5-EH2 & 93egSLEEPER

You are both right. I do have a B-series VTEC header (not factory exhaust manifold) on my CR-VTEC engine. It was labeled as for B16 99-00 Civic Si & 94-97 Del Sol VTEC and B18C1 & B18C5. I did make the assumption that since it was a tight fit on my CR-V block that it was a header for a B16 but also did fit others. My mistake. Thanks for the correction. I am one who dislikes false info as much has you two apparently do. So now I'll know for future reference.

Back to the topic,
Are you sure it's a stock B16 exhaust manifold? Sounds to me like you either have the manifold of a B16 or GS-R (same) and downpipe of a GS-R or ITR.
Anyone know if the USDM ITR has tubular exhaust manifold or cast like the GS-R & B16? That may be the only "real" (weight & flow) difference between the factory manifolds if it is tubular. Otherwise there won't be much gain or loss between the three (really two) factory manifolds.
I hope that does answer your question of if the exhaust manifold is holding you back. Most factory exhaust manifolds (except JDM ITR for example) are not going to be as efficient flowing as most aftermarket performance headers (aside from the earlier mentioned cheapy headers). But as far as the B16/GS-R manifold worse than USDM ITR manifold, again, unless the USDM ITR manifold is tubular then there shouldn't be any difference in performance (unless I'm wrong again).

B18C5-EH2

All USDM and even pre 1998 spec JDM ITR engines came with a cast iron exhaust manifold.

When referencing the part numbers (using a great program called World Pac - I order lots of parts there for my shop) for exhaust manifolds (USDM) I get:

18100-P73-A00 - that part is listed to only fit the Integra Type R.

18100-P30-000 - listed to fit 94-01 Integra GS-R and Del Sol VTEC - not sure why it omits the 99-00 Civic Si, but it should fit that too.

18100-PR4-000 is listed to fit all 92-01 Integra RS/LS/GS/SE models.

Part numbers don't always tell the whole story. Usually though there is something different about two parts if they differ in part number. Sometimes there is little/no difference as is the case with some brake pads Honda offers. Maybe all VTEC cast iron manifolds are the same, but the part numbers vary from ITR to non-ITR.

The only tubular header on a Type R was found on the JDM (maybe other non USDM models?) "98 spec" and beyond DC2 Integra Type R. It's the same model ITR that was offered with the 4.78FD tranny, 16'' 5 lug wheels, etc.

tlarimer

iTrader: (3)

I have a OEM B16A exhaust manifold on my B18B1, fits perfectly fine.

I can get pictures for you guys that say it doesnt fit.

B18C5-EH2

Re-read the thread again.

Nobody is saying the actual cast iron manifolds won't interchange.

The steel A pipe that connects the manifold to the convertor is the part that differs in length/height from the B16A to the B18 engines. You could post a pic, but it won't prove anyone wrong.

tlarimer

iTrader: (3)

I guess I misspoke, I am not trying to prove anyone wrong. What I am trying to say is that I have the OEM B16A cast manifold and B16A A pipe installed on my B18B1, it bolted right up, no clearance issues. I was never aware that it wouldn't fit, bolted it on so I didn't have to mess with my OEM cat flange or the flange on the A pipe.

b20hatchek

any b-series header or manifold will fit on any b-series because i have a gsr header on my b20b