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3rd Gen GK Specific Fit Engine Modifications, Motor Swaps, ECU Tuning Sub-ForumThreads discussing engine mods/swaps/tuning for the third generation GK Honda Fit.
Block is at golden eagle. Head is at PPR Motorsport in Turkey. Cams are at web cam in riverside. I ordered another stage 4 clutch and pressure plate and will resurface my stock flywheel. The lightened flywheel ruined my race weekend, it falsely identifies as a misfire, goes into limp mode and must be restarted. Can't race with that... i installed a limited slip diff, short throw shifter, throttle relocate. Car is ready to rock... can't imagine how beast she will be with 70 more horsepower
Thank you as always for the extremely valuable information. It helps immensely! What did you mean by capable of dealing with direct injection? I am running the ktuner v2. Hondata is also a popular option here. My tuner is comfortable tuning on either of those platforms and we are planning to add a flex fuel sensor and do a E85 (ethanol) and 91 octane tune. Cheers!
I think CarbonTek is talking about messing around with the pistons, since the DI on our L15s are tuned to form a combustion plume in the pocket on the piston face. All aftermarket pistons I’ve seen are flat faced and don’t have the DI combustion plume bowl, so maybe he’s referring to that? I think you’re gonna be the one to enlighten us to what happens with non-stock pistons, I’m hoping the effect on the DI won’t be as bad as CarbonTek is suggesting.
Thanks for the update Z062, excited to see everything put together an running. Gonna be a fast Fit !!
Well packaged Vacuum sealed for freshness Stickers FTW A gift of Turkish coffee Intake side looks good. I haven't taken measurements yet Very smooth intake porting 30mm intake 27mm exh. Unknown if they decked the head... probably just cleaned up. Top view. I have never reassembled a vtec valve train. Any pointers? Web cams said buy all new but my donor engine only had 13k miles on it so??? Great Port on the exhaust side, they made subtle channels to direct air flow, not just maxed the port. Plus i heard there are water channels to avoid so glad they did it, vs me... They used their own retainers and springs, pretty nice!
Head is back from Turkey. RZCrew intake manifold has cleared customs. Should be in this week. Block is still at Golden Eagle. The Brian Crower L15 rods are only for the civic which are shorter than ours by a couple mm, so I found some GK5 rods by @MaXpeedingRods they also have coilovers and turbos so... who knows what could happen??? which should be good enough... they say they're good for 600hp, so we'll see when I go turbo forced induction . I have asked GE to assemble the short block there. They're taking a stock head gasket and opening it up to support the larger diameter pistons. They will also select the correct bearings for each crank journal and connecting rod. I told them I'd use plastigage and they said that's for ameteurs, so in for a penny, in for a pound
This head looks good, but the exhaust port can be bigger, because you can see the old carbon build where the gasket was...
Other then that, it looks nice !
What is your power goal ? I'm really interested to see your results ! Keep the great work !
200+ crank horsepower is my goal. I agree with you on the size or at least my intent and expectation was to gasket match the port, but maybe they keep it tight because of the water jackets inside the head. I would not expect water to be flowing that far away from the "head" but @CarbonTek did say they found the jackets in trial and error. There are eight valves on the exhaust side only two are operating at any time. It could be at some time four exhaust valves are open but I'm not sure. With the small size of the exhaust valves, I'll bet it is large enough for good flow and this port will help accelerate the exhaust gasses but who knows. Remember that exit area is like the collector on a header since there is no exhaust manifold. I've got high end porting tools but I'll bet I'd lose hp if I opened it up. They used a CNC port and then probably hand polishing after. They hit 167hp on this head without cams or bottom end...
200+ crank horsepower is my goal. I agree with you on the size or at least my intent and expectation was to gasket match the port, but maybe they keep it tight because of the water jackets inside the head. I would not expect water to be flowing that far away from the "head" but CarbonTek did say they found the jackets in trial and error. There are eight valves on the exhaust side only two are operating at any time. It could be at some time four exhaust valves are open but I'm not sure. With the small size of the exhaust valves, I'll bet it is large enough for good flow and this port will help accelerate the exhaust gasses but who knows. Remember that exit area is like the collector on a header since there is no exhaust manifold. I've got high end porting tools but I'll bet I'd lose hp if I opened it up. They used a CNC port and then probably hand polishing after. They hit 167hp on this head without cams or bottom end...
Nice power goal ! I think 200 crank HP is doable. It'll make the Jazz/Fit a rocket !
I'm also sure the exhaust port is big enough as it is now, but a gasket matching avoid turbulences and flow better. It can be 1 or 2 HP loss here, but did you feel that ?
Anyway, I'm very excited to follow your thread and see the end result !
P.S.: sorry for my poor english, it's not my mother language...
Last edited by RoyDynamicgk5; Oct 31, 2020 at 07:34 PM.
Got this in from Singapore. Only problem, I wanted a wide mouth 70mm tb opening but I got the GK5 oval. I'm going to try it out on my stock engine and am asking them to build me another one with the 70mm S2K TB opening...
Got this in from Singapore. Only problem, I wanted a wide mouth 70mm tb opening but I got the GK5 oval. I'm going to try it out on my stock engine and am asking them to build me another one with the 70mm S2K TB opening...
Block is still at Golden Eagle. They have the pistons, and hopefully I get it some time in January. Otherwise I may have to haul her to Texas and look for a new tuner...
A few pics. Block should be back in a couple weeks. I am mating the block with head and cams and taking to Precision Machine for measurements and to degree in my cams... These pieces can only go one way. It's a fun puzzle... Also backwards bars and probably upside down middle intake rocker. I wonder if i could have asked web cam to modify the cam lobe at the end to increase fuel pressure. Corvettes do it on the DI motors... Covered up to prevent dust while i wait for exhaust gear. Bisimoto regrind from web cams. This motor is going to pull.... Torqueing back on the intake cam gear and vtec actuator. I went to 50ftlbs, might need more... Lining it all up Exhaust rockers in there These bars are backwards, long one on intake side...
A few pics. Block should be back in a couple weeks. I am mating the block with head and cams and taking to Precision Machine for measurements and to degree in my cams... These pieces can only go one way. It's a fun puzzle... Also backwards bars and probably upside down middle intake rocker. I wonder if i could have asked web cam to modify the cam lobe at the end to increase fuel pressure. Corvettes do it on the DI motors... Covered up to prevent dust while i wait for exhaust gear. Bisimoto regrind from web cams. This motor is going to pull.... Torqueing back on the intake cam gear and vtec actuator. I went to 50ftlbs, might need more... Lining it all up Exhaust rockers in there These bars are backwards, long one on intake side...
Awesome. Wish I could do something similar, but I gave up and went the Civic route instead. No matter how good the Civic is, though, I don't think it will match this for cool factor.
Been away for a while but this is so nice to come back to. That is one sweet looking top end my dude! Thanks for these great photos! We wanna see it running soon!
. I have asked GE to assemble the short block there. They're taking a stock head gasket and opening it up to support the larger diameter pistons. They will also select the correct bearings for each crank journal and connecting rod. I told them I'd use plastigage and they said that's for ameteurs, so in for a penny, in for a pound
