IM:B16a or B18a? what you think?

[ACE_14]

I'm trying to decide. I've got both, a B16a IM and a B18a IM. Which way do you guys think I should go with my '87 LX-i?
I picked this B16a IM off ebay awhile ago, it's already modded ready to go:






or, do you guys think I should go with this B18a IM:






the B16a with the shorter runners should be better for top end power, but I have an automatic so the B18a might be a little better with the longer runners for low end. Also it has an EGR valve the I can use. California Smog testing sucks and I don't want to keep throwing a code 12. Either way I go, they both have a bigger throttle body, I'd like to use the AEM fuel rail, but it won't fit the B18a with the EGR. I'm rebuilding an engine for higher compression a kepping it an auto, but going with a lude tranny.

Which way do you guys think I should go?

[thegreatdane]

Doesnt the B18A mani have a whole other flange than the B16 mani? In the us the B18A is from the 1.st gen teg right? I would think the TB bore is also larger on the B16 mani.

[SteveDX89]

Doesnt the B18A mani have a whole other flange than the B16 mani? In the us the B18A is from the 1.st gen teg right? I would think the TB bore is also larger on the B16 mani.

B18A is from the 2nd gen Teg. The B18 and B16 flanges are the same except for the B18C from GS-R's.

The B18A runners are longer and that will result in more torque lower in the powerband. The B16 mani has the short runners for top end hp. The choice here depends on what you want. If you more off the line power, go with the B18. If you want peak hp, go with the B16.

[88LXi68]

B16 manifold is a much better for performance. I really dont think you will feel much improvement with the b18b one because it is a similar design to our A20 manifolds.

[ACE_14]

I want something that will give me a little of both, off the line because I'm an automatic, but aswell as some improvement up top. I don't want to be chocking for air when flooring it. The TB's are the same, both off of a teg. I'd really like to use the AEM fuel rail, but it won't fit with the EGR. Does anyone know if they make a high volume fuel rail for that IM with an EGR?

[Civvy]

Which mani for turbo?

[blownoffvalve]

depends on the motor right? b16 or b18

[SteveDX89]

depends on the motor right? b16 or b18

He's putting in on the A20.

[ACE_14]

It's gonna be a rebuilt A20A3. I'm gonna go N/A with higher compression, 10.5:1, maybe 11:1.

[Lok]

If you plan to rev your rebuilt High Compression engine up to 7500-8000rpm, then I think is better to use the B16A manifold.
Also you may consider a manual gearbox swap.