New guy here, just picked up a 2015 LX manual last week, and been reading everything here for a few weeks before that.

I get that there's not too many people doing serious mods on a small economy car, but has anyone here seen any porting work done on an L15B? After learning about the integrated exhaust manifold/cylinder head casting, I've especially been wondering about extrude honing, since it doesn't look like there's any other way to really get in there.

Unfortunately for me, this is going to be a family car, so any head work would require getting another head on ebay or something to minimize down time. Very interested to see if anyone has seen it done.

 

Can't comment on porting, but any affect it might have is nothing without a way to tune your ECU to take advantage. Might be better to invest in KTuner first.

 

I've been looking at the KTuner thread, and it seems like a great system. The base map gives about as much power as I would expect without changing anything on the engine, but it's not enough to be worth it for me unless I can find out where the engine is most restricted in terms of airflow. Intake side? Exhaust side? Valve diameter? I saw a thread on here where cams didn't really help, so it's probably not there.

It's unfortunate that the companies producing exhaust systems and intakes and such for the Fit don't publish before and after dyno charts, that would give at least some information on where the gains could be found. Or at least, I haven't seen any yet.

I agree that a remap would be needed after any serious changes, though.

 

You need to buy some engine simulation software and play with that.

Engine Simulation and Modeling Software Guide

That information is virtually useless. It usually will tell you what that "one" component will do on a stock car. It's not going to give you what that one mod is going to do in combination with any other mods. Might do nothing and be a waste of money once other parts are installed? Many times if they do, they just show a dyno graph without any reference to HP or torque and scale the graph to look like a significant improvement when in actuality it might only be 2HP? In addition even if the product does what it says it will do, it might not be best for the street or even maybe the track? I have a friend who works for Dynojet and has a $40K motorcycle dyno in his garage. My bike probably spent 40+ hours on his dyno. Bought one product that claimed 5HP increase. Dyno'd the bike and sure it picked up 5HP at 13K RPM, but lost 10+HP from 4-10K RPM. Completely destroyed the area under the curve. So yea, if bragging about how much HP my bike put out it would be great, on the street it would make the bike slower so it came off and went on eBay.

BTW: I think you're on the wrong forum. Most here are interested in how overinflated tires will increase gas millage, wiper blades, how many miles they can get out of a set of tires before replacement and where they can buy them for the cheapest price with lifetime free balance and rotation.

 

I think we might actually have similar ways of looking at this- I agree that peak hp gains are nothing if there are losses elsewhere that hurt the power delivery. What kind of bike do you have? I had a similar situation with my old CBR 929, nothing impressive by today's motorcycle standards, but I almost installed an Erion full system that would have done the same thing. Loss of power everywhere but redline. Fortunately I was able to get relevant info off a CBR forum and return the parts.

I don't know about this being the wrong forum. Sure, there's not as much interest here in power, but I'm learning a lot about what works for suspension by reading other sections. Being new to the car and to the forum, though, I don't have a lot to contribute yet.

 

I have not found anyone that has did any porting on this engine. Honestly, I have not looked in the last 1.5yrs or so as well so. Perhaps you could be lucky.


I can tell you that there are gains to be had on both the intake and exhaust side. On how each part effects the area under the curve, I can't tell you specifically. I have not dyno'd this car nor will I dyno it in the future. My dyno days are over. I can tell you that with both of those modifications (and lightweight wheels/tires), it runs just as quick as some sportier cars. That is why I post 1/4 mile info.