aznboysrfr

iTrader: (10)

Ok, by now, the d17's have been out long enough for people to find out that bolt ons (namely intakes, headers, and exhausts) give very little gain. This does not hold true with previous motors (ie. the bisimotor header for a d16z6 dyno'ed an 8whp gain over stock, with no other added mods).

I've been reading many threads and why "power" mods add no power leaves my mind open to speculation. After a brief moment or two, I've come up with a few reasons ...

1 - Honda has already maxed out the power for the d17 motor. This does seem to be the case, since it does come 'optimized from the factory' .. as I read that somewhere. Optimized from that factory with keeping legalization (ie. sound muffling, etc) in mind.

2 - the boltons that are being added already beyond the point of giving much more power (ie. engine already takes in the needed amount of air, etc).

(I personally think the cam is already maxing out the air)

I suppose 1 ties in with 2 though ...

Solutions?

the two easiest solutions ... turbo, swap, n2o. Other solutions ...

1 - get a custom cam. If the engine is already intaking enough air, then a cam would have the valves open either wider or longer ... either way, having the engine consume more usable air. Higher lift would mean solution 3 would be needed

2 - upgrading valves. bigger valves, more air. ties in with solution 1.

3 - upgraded valve springs. I don't know how much the stock valve springs can handle as far as lift is concerned ... but upgrading valve springs would be good ... and as compression is greater, along with higher/longer lifting cams, revving higher would also come in handy. (*cough cough hondata's k-pro cough*)

These are the only things that I can think of that would be related to non-responsive mods ... of course the next few things would also help, but I wouldn't think they would make mods more responsive...

1. upgraded fuel system. for more air, more fuel.

2. tuning - more air, more fuel, more discrepancies between optimal fuel/air timing.

3. boring the block - allows more air, more fuel.

4. port and polish head - allows more air. best if used with a cam and/or valves that takes advantage of the extra air that is coming in.

5. port and polish intake manifold. more air. Our current plastic design seems to help for torque ... but a d16y8 intake manifold conversion (already been done) and perhaps a (ported) skunk2 d16y8 IM would be more practical for higher horsepower applications.

6. ported throttle body. more air.



someone should build a full n/a d17 ... bored block, stroked, everything. That would be nice. ;P

Skunk2ner

iTrader: (1)

i'm game haha. i love all motor cars! i'm taking donations for the cause now haha.

Dishwasher

doesn't the ecu compensate for boltons? I don't think a true N/A project could begin until Hondata comes out with that new ecu. I don't really know though.

aznboysrfr

iTrader: (10)

the ecu learns idle ... that's about it ... and sometimes it doesn't even do that correctly ...

gearbox

iTrader: (95)

I'll have to disagree with some of those.

Bored throttle body (even only a few inches)--this will cause huge low end loss and almost cause the car to stall when accelerating from a stop.

port/polish head--great for turbo, relatively no effect for NA even with oversized valves (which I also have). I really think you need a new cam to take advantage of any kind of head work.

It does seem like Honda did a fairly good jub of matching everything to the engine. This is why adding boltons to open up air flow almost always causes power loss. In the older hondas, the intake flow was not maxed out, which is why an intake really did give 10whp by itself instead of 1-2whp on our cars.
Tuning is so good from the factory, additional modification with vafc or other tool yields maybe 5whp average.

aznboysrfr

iTrader: (10)

all good points .... except that I mentioned that the last 6 points wouldn't make the car more responsive ...

boring the tb a few inches? ... mm? ;P ... in most cases, it helps when your motor is in need of more air (ie. fully built setup) ...

PnP is what I listed under the "non-responsive" mod solution ...

clarification: the 2nd set of solutions are things that would make all the other boltons more responsive ... the 3rd set are things that would further add to the 2nd set

gearbox: as far as your last paragraph goes ... that's the main point I was trying to imply ... also noted in the bit about the bisimoto header ;P

gearbox

iTrader: (95)

Oh I see. Yeah I meant mm instead of inches. So our cars are pretty hopeless looks like as far as staying NA. I'm waiting for someone to make a more aggressive cam for our cars (not regrind).

wrussi

iTrader: (1)

sad but true....

exclusive_vtec

agreed

memorex

Im not very educated on this so I have a few questions. I have an Intake as of right now.

I might have actually lost power?

I plan on modding more, exhuast, headers, pullies, tune, will this help me at all? If so how much? I eventually want to turbo, will that even help?

IronFist

iTrader: (3)

So wait, if our engines are already pretty tuned from the factory, and they still make the same HP as previous generation Civics (at least the EX does), then wtf?

6th gen EX = 127 hp (poorly tuned, bolt-ons give decent increase)
7th gen EX = 127 hp (well tuned, bolt-ons give pretty much nothing)

Why doesn't that seem right? It sounds like if the 6th gen engine was less tuned from the factory and it made the same amount of power that it was a better engine. Make sense? Like, in order to squeeze out equal performance from this one, they had to tune it better.

Ok, so the 7th gen engine has a little more torque than the 6th gen, but still. They're pretty much the same.

xX03EXx

^ Exhaust, headers, and pullies will do nothing. Pullies are the biggest of the wastes you just mentioned. And yes, yes, yes a turbo will help.

aznboysrfr

iTrader: (10)

well, the idea of my post was to motivate d17 people to not think so poorly of their engine. with an upgraded cam, I think the engine would pull very nicely since the engine is already pretty much maxed out on its air intake

02ciVike

iTrader: (1)

What is it about this engine that is causing the lack of response to n.a. mods? It just to me seems that every attempt from Gude to DH racing has been poor results when aiming for n.a.. What is holding the d17 back that isn't holding back the d16. Stock for stock a d17 car is faster then a d16 car with drivers of the same ability. My speculation is that a n.a. setup on a d17 should be greater then a n.a. setup on a d16 car because of the similar engine characteristics and the greater displacement for the d17. Maybe the answer is fundamental, maybe by comparing the difference between the d17 and d16 we can resolve this issue. ie. d17 ecu vs. d16 ecu, d16 cam vs. d17 cam, return vs. returnless, etcetera. It is less likely to be one thing that is holding the d17 back but the entire system.

acjones20

1). bolt-on power gain is a function of power present (we only have 117HP to start)

2)its only 1.7L

zachgeyer

iTrader: (3)

pullies *** your car up

Mystic3030

I have the answer, and its really quite simple: Our cars are built for low emissions and good fuel economy, they were optimized for this from the factory, and were not designed with "tuning" in mind. Its not a car thats meant to be tuned. So take it for what it is, a commuter car. If you want something fast, buy a car thats meant to be fast.

MisterFrankieJ

iTrader: (2)

very well put..

CivicsRdBest

^^ So very true!

memorex

Well I am looking to be into the low 15's to low 14's.. what do I need to accomplish this?

mootlif3

iTrader: (1)

A miracle. Or turbo/n2o.

gearbox

iTrader: (95)

Turbo for sure. And you guys forget that the 6th gen was only a lev vehicle and ours is ulev. These cars are geared more towards polluting less rather than more performance. The only miracle I see for NA is a new cam with port work and modded ecu, but even then. You really do need a turbo, because the engine is already maxed out. Adding intake and header now will be a waste because the turbo replaces those. Larger piping on the exhaust is only good for turbo.

One person here with a raceworks pnp 5 angle valve job, i/h/e, cam gear, vafcII and tuning somehow got 138whp. It's a stick, but still that most have been a great pnp job. I guess on our cars we really have to take every measure to get power. Stick with smaller rims, less weight, and keep up maintenance.

memorex

So what mods are not such a good idea that are popular? I heard Pullies were a no, what about Cam Gears, and an upgraded fuel system, downpipe.. ect?

Atticus

imo i really think every bolt on is a waste for these engines power-wise. if you want to go fast, your driving the wrong car. they pull well for what they are, but the basic stuff that works well on other 4 cylinder cars is just a waste due to previously mentioned things. Internal motor work might work, but theres no real proof of that yet. Once a company starts making preformance based cams for the d17 i think we are stuck where we are. Its fun to mod your cars, but dollar for dollar, a lot of time and money is being wasted on these motors.

02ciVike

iTrader: (1)

All engines in your typical high volume sales car are designed for low emissions and good fuel economy. The d16 was designed for this and so are the k20's that we so highly regard. This is besides the issue first brought up. Faster n.a. d15 and d16 engines have been built the same should be possible for the d17. It would be good to have the option to go all motor without swaping and FI.

gearbox

iTrader: (95)

Cam gear is useless, and pulleys are maybe 1-2whp. I just got the AEM pulleys for ps and alt so they don't really damage anything like crank pulleys. Every little bit helps I guess. It's not completely useless to mod them, but just realize that most boltons will be for looks and sound. Sometimes they give a few hp as a bonus.

aznboysrfr

iTrader: (10)

I still would think that though this car seems maxed out, it really isn't. it is maxed out as far as simple boltons go, but when someone raises the compression and adds a high lift cam, the tables will turn

Trix

How do you get 10whp from an honda with another intake????
NO way, not with original SI, or accord (maby NSX).
So you can be happy if you het 2/3 whp with intake.
Make it good cold air intake and you will win more.
PRoblem with 7th gen is that it is to heavy.

Atticus

we are talking about the motor here, theres plenty of heavy cars that can go a lot faster than ours

gelshmoff

iTrader: (1)

are they really that heavy? i thought my lx was in the neighborhood of 2300-2400 lbs. from what i've seen, other similar cars weigh in the 2800-3000 lbs range.