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Discussion Starter #1
lets say i want to spend about $5000 on a swap. what would give the best performance in a 97 lx sedan.
 

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Discussion Starter #3
ok lets say i have 8000 for the motor swap and everything. install is not going to cost me but a couple cases of beer.
 

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well lets see...
b18c (JDM) vtec around 170 -180 hp $3500
b18b (usdm) non vtec 130-140 hp $2500 (good for turbo)

just depends what you wanna do. you can turbo either one of course the ls (b18b) has lower compression which usually means better for turbo.
the b18c is cool becuase what don't they make for that engine? You could build an all motor monster.
if i had $8000
b18c5 all motor
 

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There is a tradeoff to make when it comes to turbos and compression. Just as an example, any motor running 5psi boost at 8:1 compression would consistently make more power if the compression was raised to 10:1. Now, when you have higher compression, you can extract more power from each PSI of boost than with lower compression, the tradeoff is things like detonation become more likely. Tuning is the key. I found a thread which covers this topic in the turbo forum, here's a link:

http://www.superhonda.com/forum/showthread.php?s=&threadid=63889
 

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zexed-hx & ExtremeCiv. You both are mistaken.

One main concern in power production with forced induction is effective compression. Effective compression is the sum of the motors static compression, plus the additional compression added by the forced induction tool. A B18C1 (also B16A) motor will have a higher effective compression than a B18B motor will, on the same boost...therefore, pound for pound, it will make more power.

The next argument that people usually bring up is that a higher compression is bad for turbocharging. Well, if you understand the concept of effective compression, then you should understand that this statement is entirely incorrect. A higher compression engine makes more power in NA form. So, why do you turbo guys think that a lower compression turbo motor makes more power? Does that make any sense when you really think about it? A turbocharger is a power adder? So why deplete power that was there to begin with? The answer I usually get to that is "So I can run more boost!" Well, sorry to rain on your parade, but more boost does not always equal more power. Check out this mathematical example of effective compression:

A motor with a 10.0:1 static CR boosting 10psi
10psi/14.7psi = .68
.68 + 1 = 1.68
1.68 x 10 = 16.8 effective CR

A motor with an 8.5:1 static CR boosting 10psi
10psi/14.7psi = .68
.68 + 1 = 1.68
1.68 x 8.5 = 14.28 effective CR

Now tell me who is going to make more power? The higher CR motor, or the lower CR motor?

So, maybe add more boost to the lower CR motor, right? Wrong...

A motor with an 8.5:1 static CR boosting 13psi
13psi/14.7psi = .88
.88 + 1 = 1.88
1.88 x 8.5 = 15.98 effective CR

Now you see, even adding 3psi of boost, still does not equal the effective CR of the higher compression, lower boost motor.

Effective compression is not the only advantage of the B16A/B18C1 either. The B16A/B18C1 has a stronger, better flowing cylinder head. It can rev much higher, making it that much more effective, and it flows great to handle all of the extra volume. The block has oil squirters to help support the bottom end assembly at high RPM. It takes more than a valvetrain upgrade to make a B18B safe at 8k. The higher compression also aids in spooling the turbo faster too.

Both motors have similar tolerances though. Both motors pretty much top out at around 350-400hp on stock motors, very well tuned. The B18C1 will make it far more efficiently for you though. It takes less boost to do so, it has more safeguards...and the bottom line on any Honda motor is tuning. If it is well tuned, you will be set. That goes for both motors. YOU ARE A FOOL if you think for one second that just because your B18B has a lower compression, you can substitute that for proper tuning.

A lot of people like to lower their motors compression when they build their motor. I used to think it was a good idea before I understood about tuning, and the positive aspects of compression. In the mathematical representation below, I will show you how a low compression motor must boost more to equal the output of a higher compression, lower boost motor:

Motor: stock B16A2 boosting 7psi.
Static Compression Ratio: 10.4:1

((boost psi / 14.7) + 1) x motor compression = effective compression

Stock motor (10.4:1 CR) on 7psi:
7psi/14.7psi = .47
.47 + 1 = 1.47
1.47 x 10.4 = 15.288 effective CR

Built motor (9.0:1 CR) on 7psi:
7psi/14.7psi = .47
.47 + 1 = 1.47
1.47 x 9 = 13.23 effective CR

You will lose 2.058 points from your effective compression ratio, this translates to a significant power loss.

In order to gain back that power, you have to do this:

Built motor (9.0:1 CR) on 10.5psi:
10.5psi/14.7psi = .71
.71 + 1 = 1.71
1.71 x 9 = 15.39 effective CR

Add 3.5psi to what you were boosting before, and you should be able to make around the same power as before, granted you haven't done any other kinds of modifications port/polish, cams, etc...

As you can see, considering all things stay equal (bore/stroke/cylinder head/etc...), you must add 3.5psi to make the motors perform similarly. You just spent about $2,500 to build your bottom end, and make your car slow.

By now we all should understand the positive aspects of compression, and how when teamed with the faster spoolng turbo, more efficient output, better flowing B-series VTEC cylinder heads, better low end spool time, stock oil squirters, higher redline, etc...you should see that turbocharging B-series VTEC motors is clearly not dangerous, and highly adviseable. I love a good turbo B16A!
 

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Ryan- first of all phat car.
second- I didn't read most of your post (basic math skills escape me and I was a communication major in school...not a lit. major).

However I never said either couldn't be boosted. All i said was "the ls (b18b) has lower compression which usually means better for turbo"(please note the - usually ).

k, I'm not sayin' you're wrong but I don't understand what static compression is. the "mathematical" formulas have what seem to be random #'s just thrown in there. I'M NOT SAYING YOU'RE WRONG. Maybe you could just explain little better? If you could that would be awesome...knowledge is power (you seem to have more than I do).

I read my bible (Corky Bell's Maximum Boost ) and metioned nothing of static compression. Please, please, please expand on this.
 

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zexed-hx said:
Ryan- first of all phat car.
second- I didn't read most of your post (basic math skills escape me and I was a communication major in school...not a lit. major).

However I never said either couldn't be boosted. All i said was "the ls (b18b) has lower compression which usually means better for turbo"(please note the - usually ).

k, I'm not sayin' you're wrong but I don't understand what static compression is. the "mathematical" formulas have what seem to be random #'s just thrown in there. I'M NOT SAYING YOU'RE WRONG. Maybe you could just explain little better? If you could that would be awesome...knowledge is power (you seem to have more than I do).

I read my bible (Corky Bell's Maximum Boost ) and metioned nothing of static compression. Please, please, please expand on this.
Thanks about the car.

Pretty much what that means.

Same boost level. A higher compression motor will make more power.

:cool:
 

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biskey77 said:
lets say i want to spend about $5000 on a swap. what would give the best performance in a 97 lx sedan.
I think they're good motors. But if you're going to seriously build up you're motor I think the B18B would be the best bang for you buck. Don't get me wrong I have a B18C but I think a B18B has a lot of potential too. It's just why spend $1,000 - $1500 for a B18C if you're going to change out the pistons, rods, valvetrain etc anyways. The reason why the B18C is a better motor is the vtec head, stronger built internals, shorter gear ratio in the tranny, better fuel pump..etc. Well that's just my opinion but basically everyone has their ownsetup and any motor can be built fast.

Why not get a cheap b16a 1? You can find some for $1,000 - $1,500 and build the motor up. Trannys have shorter gear ratio than a B18C and the head is known to flow better. Then you can maybe get a b18b block or a b20.
 

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Re: Re: b18c or b18b

j619pinoy said:
It's just why spend $1,000 - $1500 for a B18C if you're going to change out the pistons, rods, valvetrain etc anyways.
I meant why spend $1,000-$1,500 more for a B18C.....hehe
 

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The theories in the thread are correct. However...personally, I would pick the b18b over the b18c1. As far as comparing motors, the b18c1 is far superiorin almost every mannor...except price. The b18b is nearly $2000 cheaper! IMO, you could spend that $2000 on a Standalone Engine managment system...or possible plug and play or Hondata. An EMS would, in theory, allow you to run much higher boost, say around 15-20. There are people that run low 11's and high 10's with internally STOCK engines and EMS. HOWEVEr, (and this is a huge however) it must be tuned almost perfectly, almost all the time. This requires skill, and TIME! As well as some time on the dyno.

So depending on what you want, either engine could suit you...The b16 is a great engine, it rev's high, has the best flowing head of the 3, but lacks torque. The b18c1 does'nt rev as high, but has a good amount of torque, but also expensive. The B18b is cheapest, will put out the most torque of the 3 engines, but will NOT rev high unless you do some serious building into the head...it's very dangerous.
 

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outlawtas said:
The theories in the thread are correct. However...personally, I would pick the b18b over the b18c1. As far as comparing motors, the b18c1 is far superiorin almost every mannor...except price. The b18b is nearly $2000 cheaper! IMO, you could spend that $2000 on a Standalone Engine managment system...or possible plug and play or Hondata. An EMS would, in theory, allow you to run much higher boost, say around 15-20. There are people that run low 11's and high 10's with internally STOCK engines and EMS. HOWEVEr, (and this is a huge however) it must be tuned almost perfectly, almost all the time. This requires skill, and TIME! As well as some time on the dyno.

So depending on what you want, either engine could suit you...The b16 is a great engine, it rev's high, has the best flowing head of the 3, but lacks torque. The b18c1 does'nt rev as high, but has a good amount of torque, but also expensive. The B18b is cheapest, will put out the most torque of the 3 engines, but will NOT rev high unless you do some serious building into the head...it's very dangerous.
What you said is right on track.

Except. You don't always need a dyno in able to tune your Stand Alone.

Wide-band o2.
Street tuning.

You can't get any better then that. :cool:

Check out this article on Hondata.com

http://www.hondata.com/techwidebandtuning.html
 
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