So when I first started messing around with my car I didn't know too much- still don't. But I would ask around and then buy a bolt on mod and learn how to work with my car. So I learned how to take things apart and replace them. However I find- that matches up with my reading- that there are sacrifices to certain bolt on mods.

Correct me if I'm wrong cuz I wanna learn, but what I see is that with increasing a cars air flow it eventually loses low end torque for the high end torque. So I'm trying to find out what the right balance is. I'm doing all this to my current car so I can get a better car and do it all better at least the second time around.

Currently with my bolt on mods: CAI, 421 Header, 2.5 dia. exhaust, and f23 intake manifold, it breathes well and has more of a kick at higher speeds but I feel like my low end torque and even city MPGs have suffered. On the highway the car does great. I get up to 36 MPG at 70 mph.

So whats the science behind it if what I'm seeing is true? Or is there a placebo affect going on?

 

Ideal Gas Law
PV=nRT

Google it...and also VOLUMETRIC EFFICIENCY

But yes any change in air flow (more or less) will result in a corresponding change in power output from your motor.

 

Ok, Im looking them up and am finding more on volumetric efficiency. This is interesting. Thanks.

 

Engine basics 101: More air = more fuel = more power.
Cams & induction primarily dictate where that power will be in the rev range.
You have an untuned accord with a couple bolt-ons.
You can't monitor, log, or adjust anything.
You're trying to feel for things on the street that is tough to measure on a dyno.
I'm confident there is a lot of "placebo effect" going on.

 

I have a gauge telling me timing, fuel efficiency, temperatures, etc. Basically I can see everything the ECU reads. That and a combination of how well I know my car gives me a pretty good feel for how it acts with certain things.

 

What is this gauge?

 

An ultra gauge. slightly less expensive than a scan gauge but still does a pretty good job. ive found it pretty accurate

 

dump the ultra gayge and go see xenocron
nuff said

 

With my budget the ultra gauge and my experience with my car is the best thing I have compared to driving 6 hours to Hillburn or paying $150 for a dyno tune from some guys I dont trust to give me the best advice.
But I'm happy trying to learn how to read my car this way.

So firstly. Volumetric Efficiency. Its simple enough. But if I understand correctly- my car can only let a certain amount of air into the cylinder. That amount is increased as a improve the intake system however it can never reach 100%. Or is it that no matter what I do to a naturally aspirated engine, I cannot go past 80% by changing the intake, manifold... (although in theory a throttle body spacer even would improve the Volumetric Efficiency? Answer that if you like but thats a bit of a tangent)...
So looking at my car with the bolt on mods, one could safely say the Volumetric Efficiency has increased a bit, but the fuel going in remains the same? And so I have an improvement in fuel efficiency but not too much in low end power?

I did find a good explanation on back pressure though and I understand that more...

 

Volumetric Efficiency is the mass of air trapped in the cylinder compared to the mass of air that would exist in the swept volume of that cylinder at either ambient or manifold conditions, depending on the definition you use. I prefer to reference manifold conditions so that volumetric efficiency is a useful metric to evaluate turbocharged engines. You can always exceed 100% VE if you "cram" more air into the cylinder than would normally exist in that volume at your reference condition.

I know that probably sounds really cryptic but it's hard to simplify the definition more without making it wrong.

 

I understand the concept. Basically due to resistance the amount of pressure and therefore actual air particles is always less than the volume of the cylinder when naturally aspirated. However, given the mods one would do to an intake system that dont include any type of turbo or supercharger, whats the highest one can get it to? And if that increases from what the car was originally designed for, how would you tune the fuel mixture accordingly? Or is the ECU broad enough to do that?

That is- with the mods in my car I imagine theres a little more volumetric efficiency right? Now whats the fuel mixture doing and how can I get the most HP and fuel efficiency within my practical means?

 

Your ECU will only correct for airflow changes at part throttle - and only so much. You will need to chip and tune the ECU to correct the mixture strength. You can use a piggypack system too, but I wouldn't recommend it. You don't have direct control over both ignition timing and fueling.

There is no real limit for VE. There are practical limits for a given engine configuration, but there is no number set in stone.

 

Ok. I see. So theres a bit of an argument at what point would my car need some outside help as far as ECU tampering. At the point I am at, where I think I've done all I can to the engines breathability without forced induction, would a chipped ECU be worth it? I got one but it wasn't working right and I'm a bit wearing to spend a lot of money since this is just an experiment car. Plus I have no dyno at my disposal, itd just be on a basemap.

Also, I thought that I can retard or advance the timing by bypassing the ECU and changing the distributor angle while the car is running? I know there was something going on between OBD1 and 2 and that my car doesn't have a "real distributor". But I read a few places that I could do that.

Funny how all my posts get to this subject... but I guess its all with different people. So I wanna see what you think based on your experience.

 

You can, but your ECU will not know that you did this and neither will your Ultra gauge

 

Yeah, I assumed so. Otherwise if it did then it would correct it. But would that be an option here?
I still am trying to see if my p1297 code was anything specific. It hasnt come back on. and the p0171... I'm trying to gather info on a few different things to see where to go from here.
So why do they say that the 97 accord distributor is not a "real" distributor? Its controlled by the cam right? Just adjusted by the ECU. Or is that why?