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My 160whp B20A build thread.

4K views 30 replies 8 participants last post by  Cheeze-91lude 
#1 ·
Hey guys, so the B21a1 is definitely and finally toast at 357'000 kms :/ it runs and revs, but it's got a pretty serious knock in the bottom end, so it's time for me to start thinking about building a real engine.

I'm in school now so I won't be building for at least 8 months, but I want to put a parts list together so that if I see someone selling a part I need, I can buy it and check it off my list.

So. What I want to do is build a B20A# engine N/A to have 160 wheel horsepower. So far I know I'm going to use a bored out B20 block to 83mm, then I'd like to use my B21a1 head to go on top.

1. Can I shave the b21 head to gain compression (how low can I go)? Is a copper head gasket a good idea?

For the bottom end I want to use H23 rods and high compression pistons. I'm also going to balance the entire bottom end.

2. Is there any stock pistons that have higher compression and fit? Do B16 pistons offer that?

That's basically as far as my knowledge goes unfortunately. However I'd like to do something different with the cams.

3. I've read some threads with b16 cam shafts mentioned. What the best combination of stock/other camshafts? Also, as far as sprockets go, is aftermarket a must to reach my goal?

And then lastly comes tuning, and the question of injectors.

4. Will I need bigger injectors? If so, any suggestions? And Tuning, I'd like to get it tuned so that it runs 100%, can you tune our stock ECU's or do I have to go Aftermarket?

So yea thats it :) Is 160whp unreasonable? Any idea of what this will cost me? I'm going to TRY and get as much as I can used or for a good deal. Anyway, thanks a ton for looking and I hope you guys can teach me a thing or two. Thanks,

Cory
 
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#2 ·
From reading your post it looks as if you have not done a lot of research.

All that information is readily available from searching.

If you want to reach 160whp, then have a chat with Dexter and ask him what he did to get to that point.

I can tell you that cams are going to be your biggest cost and necessity to get to that power range.

He lost 30whp from removing his cams and putting stock back in and he had a sleeved and built B21a1 bottom end.

This build will be very expensive, and you will get some responses from members (me included)for that cost you can easily just boost your motor.
 
#3 ·
Hey Funryd thanks a lot, I actually have done a lot of research I just have trouble putting it all together in my brain (4 concussions in), and so I put forth the questions so that it's solid in my brain, and to know that I am correct in what I've read. I apologize for what seems like a noob post.

I'll definately have a chat with Dexter at some point, thanks, and I had no idea it'd be that expensive! Gnarly, well I'll see where that takes me. Thanks again
 
#5 ·
I'll answer the questions that I know about (not sure about the pistons)

1. Can I shave the b21 head to gain compression (how low can I go)? Is a copper head gasket a good idea?
Yes, and you are likely going to need to to reach your goal.

You can take quite a bit off the head assuming you get adjustable cam gears to set the cams up. Surfacing the head will also add a bit more quench area, which will usually help. This is assuming the head you will use hasn't been surfaced before. Best to ask the machinist how much.

Copper gasket is a terrible idea. These are usually used on high hp engines in which the block and/or head are o-ringed. Not necessary for you. Stick with a Cometic.

3. I've read some threads with b16 cam shafts mentioned. What the best combination of stock/other camshafts? Also, as far as sprockets go, is aftermarket a must to reach my goal?
B16 cams will not work as they are VTEC and our heads are not. I'm currently at 165whp with B18B intake and B21 exhaust cams.

Any B18 cam can be made to fit. Serch around a bit to see what needs to be done.

You will likely need cam gears so you can set up the cams after surfacing the head and adjust for more overlap.

4. Will I need bigger injectors? If so, any suggestions? And Tuning, I'd like to get it tuned so that it runs 100%, can you tune our stock ECU's or do I have to go Aftermarket?
I'm using 240cc Integra injectors. I believe the stock are the same size. Someone correct me if I'm wrong. As I said, I'm at 165whp with them, but I do have an adjustable fuel pressure regulator, so you might need one of those as well. I can't recall if I'm at stock pressure or if it's higher.

You will have to get a tunable ECU and have it tuned. There are several you can get, usually from civics and integras. It will need to be chipped in order to do so.
 
#7 · (Edited)
I lost 37 hp taking the cams out and having incorrect cam timing. I'll be getting in retuned in the upcoming month to see what she makes with the correct timing, it ran lean enough up top once I set the timing right, that I had to close the secondaries and bump up the fuel pressure until I can get it tuned again.

My build is as follows

AEBS sleeves
Eagle rods
Wiseco 84mm 8.5:1 pistons
Ported and polished head
Stock valves
H22 valve springs
I had Gude .410 lift 258 duration cams
Adjustable cam gears
B20 intake with modified plenum and plenum spacer
65mm TB
5th gen AEM 3" intake
OBX 'Race' header(I do not recommend this header, primaries are tiny)
450cc DSM blacktop injectors(Which were maxxed on my 167hp run due to a failing stock fuel pump. With a better pump I would have made more power)
Bosch 044 300lph pump
MSD 6AL
Blaster SS coil
Aasco Motorsports 9lb flywheel
Tuned on Crome Pro with a PO6 ecu

You won't need sleeves and if you use H23 rods and B16 pistons you'll save money there.

My runs were on a Dyno Dynamics dyno, they read 10%-15% lower than Dynojets on average.



Yes, I was revving out to 7500, actually I've revved it to 8500 in the rain by accident, don't recommend that tho.

On the stock cams and skewed timing I made 130hp/140tq. I was also having problems with it misfiring above 5k due to the cyp sensor going bad, switching to a LS dizzy has fixed that.
 
#10 ·
Think I've asked you this before, but what is the dip in power around 3750? When the IAB's open up?

Pretty good torque for sure! Think mine made 145
 
#12 ·
:p
Man, Dexter thanks for posting that for me I really appreciate it! I'll be honest I feel a little stupid, I always chuckled at people asking about what seemed to me as ridiculous build questions, now I feel like I'm being a hypocrite.

I had no idea that much modification was required to get 160 whp, I always thought that 200whp was the crazy number to achieve. (which now seems incredibly tough). But yea, thanks for the info guys I appreciate it.
It's not much off of any other build honestly. Headwork, cams, higher compression pistons, tuning. I'm built for boost hence the low compression pistons and forged internals. 200 is definitely doable, on a Dynojet I would have seen over 180whp.
Think I've asked you this before, but what is the dip in power around 3750? When the IAB's open up?

Pretty good torque for sure! Think mine made 145
They were opening at 3800, possibly should have had them open sooner. Could have also been a strange spot for the intake mani and cams. I've always wondered why it did that too.

Yeah, it definitely makes torque with the stroke.
 
#9 ·
Man, Dexter thanks for posting that for me I really appreciate it! I'll be honest I feel a little stupid, I always chuckled at people asking about what seemed to me as ridiculous build questions, now I feel like I'm being a hypocrite.

I had no idea that much modification was required to get 160 whp, I always thought that 200whp was the crazy number to achieve. (which now seems incredibly tough). But yea, thanks for the info guys I appreciate it.
 
#11 · (Edited)
Check out my build too if you want. I went a different route than Dexter. Probably cost a bit more I'm guessing. I think 200 whp is achievable. I'm sure as hell going to try for it. My head is currently of getting a valve job and getting the combustion chambers welded for more quench and higher compression. That with cams I'm hoping will get me close anyway!

http://www.preludepower.com/forums/showthread.php?t=347098&highlight=

Edit: just looked over Dexter's build. Guessing costs were similar, I just did it a different way.
 
#14 ·
Yea I was a little confused about different Dyno's as well. A kid I know had a D series "ZC" engine with all internals forged, compression at 8.5:1, and he was saying he had 246 whp, and it was bored to 2.2L. the 246 number came from, he claims, a dyno in town. There is NO WAY! he had 246 wheel hp, having a N/A 2.2L with 8.5:1 compression. Further evidance was his acceleration was not near that number. So if every Dyno is different, is there really any point besides tuning? (for your own knowledge). Because 180hp on one Dyno seems like it could be 160 on another. Dyno's are still fuzzy to me.
 
#24 ·
I was thinking that might be estimated flywheel hp, but that still seems high. Assuming a 15% drivetrain loss, that would put it around 209 whp. That seems like BS.

doesn't the h22 valve spring a better mod then stock tho?
Heavier springs when you don't need them is going to lose hp due to friction. You've really just got to find a balance between heavy enough to keep the valves from floating and light enough to minimize frictional losses. For stock valves, go with stock springs for sure.
 
#15 ·
Well I have only ever used a dyno for tuning purposes.
I have compared dyno runs on the same dyno between different cars but it's very hit and miss to compare different runs on different days let alone on different dynos.

The actual numbers aren't that important as long as the engine is healthy and doing what it can.
 
#22 · (Edited)
I'm sure you'd make at least 150 with that cam combo and compression with a good tune. Add in an adjustable fuel pressure regulator as well as at least a vigor/ported stock throttle body, and a lightweight flywheel.

http://www.preludepower.com/forums/showthread.php?t=304416&highlight=dyno+thread

http://www.preludepower.com/forums/showpost.php?p=2012970&postcount=172

^^That was with stock compression and a stock header, stock sized throttle body and as far as I know stock plenum/intake manifold.
 
#27 ·
B16 pistons would already give you a good bump in compression. And dont forget when you go higher compression that you need higher octane fuel. And i think b16 would bump you to like11:1 or higher if you shave the head and or block.
 
#29 ·
Yeah if you wanna run the b16 pistons thow you have to bore the part where the wrist pin goes 1mm bigger. That has to be done at a shop precise measurement. After that just put back together with b18 intake cam and adjustable cam gear and vigor throttle body and port and polish intake manifold and that sounds like a good build. Might need to upgrade injectors and if your doing all that you better get a tune which you will have to convert to obd1. Dont do all that and not tune waste of time if you do that.
 
#30 ·
Lucky for me I'm 1990 so tuning won't be a problem, and it's definitely something I had in mind to do. Thanks for the info bro I appreciate it, what you listed is basically all what I have in mind, forgot about the wrist pin though! Can't wait to get going on this puppy, gonna be a long school year xD
 
#31 ·
So you have a b21? Thats the only way you can swap ecu it will be obd1. If not you will have to do harness swap. And you have to bore wrist pin to run any b series piston except bastard b. you might have to do more work than you think.
 
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