Hey guys I'm thinking about having my 2011 ge8 flow-tested to see what restriction I can do away with. Will an ecu reflash be necessary? If I get after market headers will those mess with the port work?

 

Getting a stock head flow tested would be awesome to know how many cfm it is flowing. Porting the l15a heads is difficult due to the lack of material between the port and the water jacket. Skunk2 posted up a video about porting the l15a1 head which mainly consistended of them blending in the casting lines and smoothing out the area under the valve seat where the machine marks were rough.

A header allows exhaust gases to leave the ports easier so it would only help the engines breathing ability. Especially if it has been ported. Just remember that bigger is not always better since you can easily kill air velocity which would lower cfm numbers.

 

But if I were to get an aftermarket intake and exhaust manifold, but after porting the engine would it affect flow? As opposed to porting once I have the newer parts in.

 

Anything you bolt on will only help flow. Don't expect big numbers though. Flow testing the head will help get solid data about the motor itself. Anything you can do to increase those cfm numbers will help out the overall engine's volumetric efficiency. Even if you run a ported head with stock intake/exhaust manifolds, it will still breathe better.

Read David vizard's book porting and polishing. It will explain quite a bit about how to improve air flow and how that helps the engines performance

 

I think you should focus on de-shrouding the valves more, then porting. de-shrouding made a HUGE improvement on all the D series motors I ever got the chance to play with.

Its a sideeffect of having small bore and 4 valves per cylinder.

 

Thanks! I'll look into that

 

Also, you're not really going to be getting an exhaust manifold, being that the L15 in the GE the upper section (what would normally be the exmani) is cast as part of the head. The best you can do is to remove the 2 catalysts. Even removing the secondary catalyst is an improvement and doesn't mess with the ECU as far as A/F goes since the sensor sits in front of the catalyst.

It would be nice to see how much the head can flow to see if worthwhile to increase the rev limit further, currently with my reflash from J's it increased the revs 300rpm from stock and from my seat of the pants feeling, I do feel as though the car is not losing power at cut-off and another 500rpms would be doable. Strengthening the bottom end to withstand higher revs plus more combustion, a new cam and with revs towards 8500 would make the Fit even that much more fun.

I would just like the extra revs at least right now as I am gear limited to 205km/h. It sucks.

 

The 1.5 has a MAF sensor so the ECU would see any increased airflow. The relationships between MAF, MAP, and TPS would change but ultimately the ECU would relearn this and fine-tune injector on time via O2 sensor feedback.

 

Well I completely didn't read about the ge8 part. I would definitely focus on the valve shroud then since that is about as much as you will be able to get to blend due to the integrated manifold.

 

valve de-shrouding will give you a very nice increase in flow velocity, especially mid cam-lift.

Also thinning the valve stem directly above valve face will allow more air into the chamber at the same cam lobe height.


There are a TON of motor techniques to do on these motors, and they are effective on almost any mass produced motor that isnt built with a strict racing pedigree.