I was wondering what mods would help improve on a B20z's power without sacrificing mpg. Here were some of my thoughts from my online reading. Please correct me where I'm wrong as I'm no doubt a Honda noob.

Maybe good:
1) Porting on the intake manifold on the side that goes to the head.
2) Port match the head to the intake.
3) Use a P8R head (increases compression)
4) Not too large of an exhaust 2" inches maybe 2 1/2"
5) stock LS throttlebody and LS instake (see #1)
6) stock cams (good for mpg not so much for power)
7) Decent air filter and piping maybe cold air if it has a one way to keep water out.
8) stock exhaust manifold...I'm not sure about any aftermarket headers that will help mpg along with torque to worthy extent.
9) A good tune may be the best mod of all. Is this true?

Maybe Bad:
1) Large exhaust (I'm guessing over 2 1/2" is overkill) in general bad for mpg and power and kills torque
2) Cams don't help mpg so the added hp doesn't appeal to me unless there is a good cam I'm not aware of
3) Porting the exhaust side of the head is bad for mpg and power improvements are marginal.

 

i was about to wonder how does this work .. more power but not more gas .. from my basic understanding of it to make more power u need more gas & air mixture ..

 

What kind of driving will you be doing.. if this is just for getting around and not playing around, then leave everything stock.

Honda B20's come from factory with alot of restrictions. So adding in bolt ons like a cold air induction and changing the exhaust manifold/exhaust system will free up restrictions and let the engine breathe better.

An engine is one big air pump, the more air you can get in & out, the better it performs. Also, colder air is more dense and therefore has more oxygen, so more O2 = more fuel for better A/F optimization. Ever drive your car a little hard when its cold and it seems like theres more power? Cold air intake will help with that.

Your questions up there are all over the place..figure out what you what to do with the engine, pick a realistic power goal, then go from there. My B20 with just Intake, header and exhaust made 149whp/143tq = 167 crank hp/160 crank tq

 

any modification that increases the efficiency of the motor will increase power and MPG. so anything that has to do with air, fuel, and spark.

easy things like intake header exhaust. 2.5" is fine. better technology fuel injectors. RDX injectors have a finer spray pattern and better atomization, and some good NGK plugs and wires. (plugs and wires are prolly the least effective out of the list but it doesnt hurt to have quality ignition parts).

also things to help fuel efficiency would be lighter wheels, eco tires, and a properly running and clean engine.

maintenance is more important than modification. even things like old brakes can lower your MPG's, as well as proper tune and working O2 sensors and such. good luck!

 

Didn't really mean for them to be all over the place as I was mostly just listing some things I've read online and some of my own assumptions and wanted confirmation or disproval of what I thought was true or not.

That much power and torque would please me greatly in my Civic The way I figure wheel horsepower I think you are making closer to 175hp at the crank...I calculate it 149/.85=175. I'm going to be using an auto so my whp will be somewhat less.

Now that I think about it. If you don't mind me asking I'm a bit curious as to what intake, header, and exhaust I should use to make this much power? One condition I will sacrifice power for (but not too much power) is for the exhaust to be not too loud and obnoxious.

 

if your looking for a very quiet exhaust, go with ether the Tenabe or Apexi. they both make really quiet options. but keep in mind a quiet exhaust will hold you back on power.

i would personally go with like a piping kit from Kteller and customize it with what ever muffler you want and what ever resonator you want. as well as highflow cat or w.e

 

i have some drop in Crane cams im selling that are perfect for stock engines.

http://hondamarketplace.com/showthre...ght=crane+cams

 

Lets bring up the number one point. Modifications & Gas mileage. First off, those two dont mix unless your apart of the ecomodder forums.

Ill put it this way, exhaust & intake, provide more air.

More air=More fuel.

Cams, the point of them is mainly to enhance other modifications such as upgraded fuel system, etc.

Again, more fuel.

If however you are asking what modifications are available that arent TOO detrimental to fuel economy, thats a different story. To be completely honest with you, most minor bolt ons wont effect your fuel economy too bad. Unless you have a heavy foot.

 

Theres a thing called efficiency of the motor.
More bang with same amount of fuel.
Stock motor is a compromise between power emissions and reliability
Beter fuel atomization=better efficiency
Ported head and portmatched im. =less restriction=better efficiency
Same with better flowing exhaust.
Then higher compression also helps
Lighter wheels with right thread pattern
And of course properly tuned

People that say more power=more gas are not always corect we dont drive around town at full throttle
Properly tuned b series gets more power and better gas mileage at yhe expense of emissions(mostly noise)

 

It's all in the tune. I just hit 300 miles/tank this week (on a gs-r trans, average consumption of 29.2mpg) and looking to do better on the next tank. Up from around 250 miles/tank.

The other important mod you can do is to your driving. If you're romping on it and driving 85mph on the highway, you're going to consume fuel.

Your list mostly resembles my build though, so yes, decent mileage is achievable.

 

Ahh yes.. i forgot.. the right foot controls most MPG's

 

Going on per tank consumption is a pretty inaccurate way to see how you're doing though. I think I might build one of these this week:

http://spiffie.org/kits/mpguino/

 

I agree completely. I think most of my question is what mods on these B20s are best for what I want.

I think cams are out of the question because a radical cam usually equals more less gas mileage.

I would like to port the head but I think I've read somewhere that porting one side is pointless and probably will hurt mpg (exhaust side I think).

I am also considering better injectors now maybe RDX but then I'd definitely feel the need for a dyno tune which I think would pay itself off in fuel economy and probably piece of mind from running lean.

I suppose my biggest question is what mods are worth my money without hurting my mpg? Budget and fuel economy may keep me from some of these but others may be must modifications if the benefits are great enough.

 

Realy is a same thing
You can go by half a tank
I put 5 gallons in and run til light is on then see how many miles 8 made
Dont need a gauge to tell me that when im in vtec i dont care about gas mileage obviously.

 

Intake header exhaust rdx injectors and a good tune

Better mod would be a vtec head with itr cams or similar
Cams that have a very small lift on primary lobes.
Bc3+ cams are pretty good for daily driver.
Tire thread and wheel weight also play a big role in freeway mpg.

 

Yeah I cruise about 75-85mph depending on traffic speed...yes we have a lot of heavy footed drivers on my commute to and from work...but I only romp on the gas when I need to merge and that's because the 1.6L (d7) is really weak. My car still gets 30-35mpg that way. I figure I won't have to stuff my foot to the floor as much if I have a B20 even if it is an auto.

I have 99-00 Si wheels I'm a tad bit lighter than with the steal wheels I believe.

I would love to goe vtec b20 but I think the cost of the head and modifications would put me way out of budget plus I think mpg will be shot once I put the proper automatic transmission (jdm b16a I believe) to it.

 

tire PSI also and having the engine in peak shape makes a difference

 

I dont think si wheels are light. They are a bit heavier than webs and blades

 

A lot of this will be in the tune. And you'll need to tune the part throttle for ignition to get the best gas mileage. That's the trickiest part of tuning. When the ignition is right, you push the gas less at the same cruising speed, saving gas.

I'll give you an example. My B18 LS with Crower stg2 cams started out getting 24mpg. I worked on it a bit and got it to 27mpg. Then I leaned it out and bumped up my timing and now I'm getting 30mpg mixed highway/city. I also have B16 IM and 3in exhaust.

If you tune that B20 right, then you'll hardly be pushing the gas at all when cruising. And if you need to accelerate just a little, you'll be able to push on the gas less than a poorly tuned motor. VTEC would help with that.

And yes, a real-time guage would be really nice to have.

 

vtec is over rated. theres plenty of non vtec build that still put down respectable numbers and mpg numbers and can keep right up to their vtec counterparts.

On the street, im all about torque..

 

Good info...regretfully I won't be using VTEC though. I'll come closer to going turbo than I will VTEC but turbo would be a few years out if at all...low boost though.

 

Yeah I didn't want to put much money into wheels but I was tired of the steelies but I think SI wheels are at least lighter than the 14" steelies.

 

Vtec haters unite lol
Who gives a sht vtec or non vtec,
With same cams and ports b20 and b20 vtec will be same power
Low cam adds flexibility and better idle along with part throttle.
Thats why ls motor is rated at 146 and itr motor is rated at 200.
If there was no difference thwn honda would use same motor in all their cars..
This pride in non vtec motors makes little sense. Everyone knows you can make power but not many understand what vtec really does

 

 

Nothing against VTEC here but since I'm going with an automatic I just can't rationalize going VTEC because of the added costs of finding the right automatic and tuning issues plus the extra cost of machining the head for VTEC.

VTEC triggers an extra cam lobe at higher rpm which allows the engine to still making power at higher power (in a nutshell). Is that somewhat correct? Oh and it was originally designed for better mpg.