[quote=jscooter;284632]airflow mods(p&p,cams,larger turbo,ect..) will help you close down that psi gap. you'll make more power per psi. you have to look at psi as restriction. ultimatly you need airflow! honestly i'd be very suprised to se you make 250whp with only 10psi. i'm guessing more in the neighborhood of 15-20psi. but depends on the turbo. i'm sure a t3/t4 would make your power goal with low boost, but talk about lag. don't be afraid of psi. properly tuned you'll be ok with higher boost. or just run a alky injection kit with a few fail safe's then crank on it. but I feel you need to step into the t3 or bigger realm if you going for 250whp. and that evo 16g with a properly built twin scroll manifold might just be the ticket for you.

ok well like i said my goal is to run a 13.99 or higher...with the weight of a fit, how much horse do you think i would need (just asking) but i DO wanna push between 225-250. THANKS for the info i will put it in my notes fo what to buy for a turbo...i think i might build my own since i would like to keep my fogs so i will need custom IC piping. so you recommend the 16g for the goals i want? what do you mean a properly built twins scroll manifold?...what is that? is that the ones that look like the horns of a ram? (sorry i know NOTHING about these like I said...lol)

if your honestly wanting 250whp the evo 16g will be a safe bet. as for a twin scroll manifold. that means when your running a divided turbo(where it has two inlets to the turbine. you pair cylinders 1&4 to one half and 2&3 to the other inlet of the turbo and what this does is it helps with cylinder scavenging. the results are rediculas. you can run larger exhaust housings/turbos with the spool of a smaller turbo.

if you're at a relatively low altitude, 200whp will be enough to reach that goal.

I don't really feel like reading this entire thread, but which L15A engine are you getting? One from a GD3 or from a GE8?

Because the only difference between the JDM GD3 engine and the usdm GD3 engine is the usdm has DBW throttle, jdm GD3 has a longer/closer geared transmission, and i think that's about it.

Although the difference between usdm GD3 and jdm GE8 is a lot more profound, I'm not going to list all the differences as there are too many, but here is a link showing all the differences:

Honda L-Series SOHC i-VTEC Engines for the new GD Honda Fit/Jazz

The only thing that isn't really mentioned is that the jdm GE8 gets pretty much the same transmission as we get on the usdm GD3, so if you're planning on making a lot of power and want longer gears you'll need the jdm GD3 tranny.

You do realize that you're going to have to convert your gas pedal to drive by cable throttle right? meaning you'll probably have to drill through your firewall.

Also because the new GE8 Honda Fit in japan comes with DBW throttle J's Racing now makes an aftermarket DBW throttle body for the GE8, or if just don't like the feel of DBW and like cable more than get a Throttle controller, which is basically plug and play and a lot less hassle than converting from DBW

https://www.fitfreak.net/forums/fit-...le+controllers

PRODUCT

Why does everyone want to go about things the hard way. a JDM L15 canot be properly controlled by a stock USDM computer. The USDM compter relies very heavily on throttle position to determine ignition advance and fuelling. no DBW=funny running engine. a Japanese ECU would require a japanese cluster and key set as well. and would have to be from a 2006-2007GD3 Model with manaul transmission.

Also going with a thicker head gasket adds alot more "potential" for problems. Best way to shave some volume from the combustion chamber, get recessed valves. Stock rods and pistons from what info I've found can hold up around 200Whp, but never found mention as to how relible this was or how long it lasted. (Anyone remember the mythical 500Whp stock internals SRT-4, 500Whp on the dyno.. 3rd run down the track and block split among other things)..

For coice on turbos and GT25R (Not to be confused wth GT25/40R) would be a great choice. Can support around 220Bhp and should spool like a champ on the L15.

Exactly. That's why i had stopped posting on this thread.

the engine was from an 07 5spd gd3. i am getting the ecu with it. you have to understand, i dont plan on this being easy. when i bought the engine, i didnt say to myself "oh i am just going to throw some pistons and rods in this and it will be good to go. i know it will mostly be trial and error as no one that i know of has built an L15 for boost.

it's nothing special. It's just like any other new, not overly aftermarket supported engine that engine builders build all the time anyways.

All it takes is custom parts, there shouldn't be any trial and error since a motor is just a motor. Only things I foresee being unusual is ECU tuning since you are obliged to keep the factory original ECU and guage cluster in the car for your dash to work. Get a custom made throttle body and go full standalone. and piggy back thestock ECU just so your dash works.

If you recess the valves you will DECREASE flow because the valves will be more shrouded by putting them further into the head making less power.

i live in arkansas ...havent been there long so not sure about elevatin but i bet it is low...i was thinking 225 ensure me to my goal..so will just stay with that number...lol

THANKS to all the posted...sorry kelso didnt mean to jack your thread :o

its cool man, ive been so busy getting parts together for my other project, ive barely had time to check the boards. but this thread has some awesome info for me and anyone else that is doing the same thing i am.

Same concept as lower compression pistons. You lose power from lwoered compression, but gain the ability to run more boost. You won't make the power as efficiently but it opens up more horses, even if theya re old and sick :)