Okay stupid question but i want specifics......

[Juicy05]

OKay, i own a 91 hf crx, with the 91 si swap, well it had been running really crappy, well i began to run some numbers on the parts under the hood and realized that the guy who owned the car ( he did the swap before my purchase) didnt put the Si intake manifold, header, or the ecu, well i bought an si ecu put it on, but the car is still gonna run like shit with the hf parts correct? hesitant boggy? crappy accel? please give me any feed back im just curious as to if that is the problem for sure........thanks!

[91hbman]

well if you have an si motor i would deffinatly take off that hf stuff and bolt up the si manifold. make sure there isnt anything wrong with the motor itself. but im sure a si intake manifold will let the sir get in better.

[90civicracer]

He said he has a Si swap, not the SiR. And If that means you have the hf intake manifold isn't that DPFI...I'm not sure but if it is that is what is robbing you of power, MPFI gives you a lot better performance. Also I do believe the Si exhaust manifold is a little less restrictive than the hf but then again I could be wrong.

[88ReX]

The hf is MPFI but I'm sure the'r intake and exhaust mani's flow like pencils. The si manifolds will flow much better and I'm sure the ecu will help out too.

cheers

[91hbman]

oops my bad i guess a had a typo on my post, yes she did say si

[4G4D Store]

ya - definitly get the Si manifold - the ports are MUCH bigger - you'll get a lot more air flow into the engine - I have both intake manifolds - I'll take pics so you can see the difference. I'm not sure on the exhaust manifold - I have a HF one of those also - but I'm thinking it's pretty close to the same as the Si - I'll check tomorrow on that too.

[91civicDXdude]

the HF exhaust manifold is famous for home made turbo setups with major porting, but it sucks for anything other than that. its very short, it has very small runners with very small ports.

Use a d16a6/d16z6/d16y8/d15b7 intake manifold and a PM6/PG7/PM7 ECU and you'll be set. Get an aftermarket header.