hey yall, i got a b20z block with 12.5:1 cast pistons stock rods and crank. all has been cleaned up and balanced from machine shop. im using a b16a head with the golden eagle head gasket. stock valves and 85lb duel springs. skunk 2 gen 1 ITR intake manifold with a 70mm throttle body port matched. ive been stuck on getting a couple parts for it and have no one to really talk to about it. i figured maybe someone could help me out!

im looking for a good exhaust header that wont break the bank. i was looking into the 4-2-1 style as im setting my redline to 8200 and will be street driving and some auto x. the skunk 2 alpha header looked good but i was also looking at the PLM tri Y big tube. what one would be better fit for my set up?

also i still have no clue what cams i am going to use. i want to run something aggressive without hitting the pistons with my compression. i was looking at the buddy club 3s?? im no expert at anything of this nature as this is my first real "build" i usually just build a stock engine with IHE. im running a 2.5 cat back with a 2.5 test pipe.

anyone have some ideas or opinions? im new to this so go easy on me! thanks

 

Spec3 too weak for 12.5:1. Buddy club spec4. Or toda cams or jun
Check if 85 lb work with bc4
get arp rod bolts if u haven’t.

look into 3” exhaust if possible

 

I have arp head studs and rod bolts so I think it should hold.. my only concern with spec 4s is the valve clearance... would their be a downside to using spec 3s? also do you have input on the header? I appreciate the reply

 

also I kinda just bought my apexi ws2 cat back this summer so idk if im ready to get a new one yet... works good with my b16 but would it bottle neck the b20v?

 

spec4 would be perfectly fine
spec3 is too weak more for stock bolt on type

the real answer with valve to piston clearance rod claying when assembled

the apexi is good
its true 2.36” which is okay. But 3” will breath better. It’ll be a bottleneck but if u have it already just use it unless someone pays good price for it
Bc 3” exhaust will cost you probably 220 for 3” straight pipe prebent. Then a 3” muffler is 120-150
so that’s 350-370 plus the welding muffler is another. 50-80
id just use the apexi unless u can sell it for 400-450

header idk

 

okay thank you for the info ill look into that

 

My first thought was 3” exhaust. On the motor you’re building it should make a stout difference.

 

That depends on who you ask...
You see, there is this thing call "Fluid Dynamics" that tends to dispel this need for giant exhaust on even high output NA Honda 4-cylinder engines... especially "B" series ones like the OP has. At around 200 wheel HP, the Apexi 60mm pipe will work just fine.

 

Work just fine maybe, but I'd put my money on a material improvement to the overall powerband with a 3". Enough to justify the upgrade. At least that's what I've seen on my builds.

 

awesome good info guys, i ordered the skunk 2 alpha header last night. i was between that and the tri y PLM but i figured the skunk 2 might be … stronger? idk lol now im just looking for cams. i looked into 3'' exhausts last night and i don't really have the money for a whole new exhaust when mine has about 3000 miles on it lol... defiantly going to upgrade in the future but as mentioned above i think it should function well with the set up. 3'' is probably better but ill save that for next summer. im setting redline at 8200 just like the b16a. i dont wanna blow up the b20 ive done a really nice job building this so far. didnt just slap some junk yard **** together

 

Toda B works well. I ran that, and also mix matched with long duration comp cam when I was 12.5:1.

I’m running more compression now and running mixed toda b/bc4 cams. lots of duration. I built a 3” exhaust with 2 resonators and one strait through big oval muffler, it’s not bad at idle but over 9000rpm it’s very, very loud.

 

I use a 1320 toda rep header with my b20v that I autocross. Love the ground clearance and I had plenty of torque for autocross in a heavy integra with a gsr trans. Usually at low rpms in 2nd gear in some corners depending on course design.

 

nice man, how do you like it for auto x? i plan to get out there next season with my b20v i ended up going with the skunk 2 alpha header, hope it performs well!! still looking for cams and trying to figure out injector size and i think the rest should be easy!

 

also im pretty confident it wil be fine but i get nervous about doing **** wrong, will the 12.5:1 compression be fine on 93 pump gas with a tune? i dont have access to e85 nor do i know how the **** that works with all the flex fuel stuff lol. i dont know if its even true 12.5:1 compression. i ordered the cast p30 pistons which give you ''12.5:1" with a b16 head so i assume it would be around there. also on the high compression topic what NGK plugs would be the best to run? im assuming something cooler? alot of talk asbout the NGK 7s? but do they come in a iridium, or copper, platinum? what would be the best plug to run? another thing with the plugs ive rear some plugs will hit the piston with high compression like mine? is this true?

 

anyone? bump

 

I ran accel 310cc on my 12:5:1 b20v. I'm breaking in my new engine with prelude 290cc, watching the duty cycle very carefully.(***EDIT, I ran out of injector with the 290cc, duty cycle maxed out) Added fuel pressure and walbro 255 on both setups.

93 octane is fine as long as you have a decent cam. I'm currently street tuning my 14:1 on 94 octane and again I'm watching the knock sensor very carefully.

I'm running 1 step colder NGK iridiums. There's no way the piston will contact the spark plug for something you are buying off the shelf, the only way is if you are running custom length rods or pistons you spec'd out and had made. Still it's a good practice to check your clearances while putting it all together.

 

okay thank you for the reassurance, when you get plugs do you get them for a b16 or b20? I can't remember if they are the same or not. also do you just throw them in or do you gap them to anything? I have a p28 ecu. no knock sensor... alittle scary

 

It was great. Pulled strong especially since I'm just finding out I had a slightly hurt motor. But biggest problem was no LSD. Couldn't put power down with RE71R tires until I was damn near straight. I bought a Mfactory Helical LSD with stage 1 race pack.

 

awesome. can't wait thanks man

 

what spark plugs do you ask for at the part store? b16 or b20 plugs?

 

B16

 

i ordered the bkr7e-11s copper. what should i gap to?