as I look over the forums I am see that more and more people are posting that they have gone the F.I route and boosted there fit or are asking about doing such mods. however as many know, nobody is willing to push beyond the 200hp mark in fear that they may blow there engine.(Which makes sense, the bottom end is not that strong) I have also noticed that a few people on the forums have gone the k swap route and may have a spare l15 laying around. (if they have not sold it yet) What I am posting about is that soon enough people are gonna want to turn up the boost there there fits. (Its inevitable it happens to anyone with a boosted car stock or modified) And people are going to have to upgrade there internals somehow to get beyond this 200hp barrier. I think I could have a cheap solution with the help of a few people to get to the 300hp limit. after which most people will stop there. (the fit is so lite that anything between 200 and 300hp should be enough for most normal people)

Connecting Rods.
anyone who is tearing apart there l15 or has one laying around. What is the rod length of the l15 engine. if its 137mm we may be in luck. 137mm is th1 most common rod length of any honda series engine. therefor modified stock b-series or aftermarket d-series rods could be adapted for use in the l15. cheap rods

Pistons
this is where is gets weird. the l15 in teh usdm and jdm fit's has a 73mm bore. the d-series has a 75mm bore. If you are up to it you could have th eblock machined to accept the 75mm d-series pistons. (aftermarket of course) Now because I don't know the heads of l series engine i don't know what Vitara would do to the compression ratio (how low would it go.) Vitara pistons are pistons from a suzuka Vitara. it was found that the flat top pistons would work in a d-series engine and lower the cp. for boosting applications and hold up quite well for how cheap they where.

With these mods 300hp could be a possibility in a l15 fit. but then again this is all theory. I realize that the d-series and l series are completely different but if it turns out that these cheap parts could infact work in a l15. getting to 300hp wouldn't require custom parts or a costly and impractical (for the time being) k-swap.

 

the flow of the head sucks... This is why it is hard to get the power there. It can and has been done, but the OEM pistons/rods arent whats holding the motor back its the head. The walls on the head are so thin its hard to port because its starts going through the wall right away.

 

Then couldn't you weld the ports (put material on the walls of the part) and then sculpt the ports from there.

 

I personally haven't pulled a head off but I'm guessing you port into water which would be very hard to weld up if at all possible then you may run into cooling issues. I wouldn't try to go 75mm bore. thats a huge jump in bore. .5mm is .020" so that would be .080" overbore which is insane on stock sleeves. i'm sure there are 73mm slugs out there that could work. there are tons of small displacement turbo cars out there. toyota's, puegot, renault, ect....

 

i'd like to see this happen, if it can...

 

L15 bottom end is stronger than most give it credit for. the head is the weak link. with a good port job you might get a 15% increase in flow but your chancing killing a head. mild P&P bigger throttle body custom intake manifold. and FI should make it easy to hit the 200hp mark. IMO the bottom end should be able to take it.

Cheapest most reliable route to go is a K24 swap from a CR-V or accord. with port work, intake, header, exhaust an K-pro. should be good for over 200Whp. and cost less than a K20A2 swap (RSX type S)

 

I meant welding the ports by welding the actual port. where air and exhaust flows through. It. could be done to smooth out the ports by welding over the rough areas in/around the ports and then grinding them to a desired smoothness to maximize flow.

 

I don't think smoothness is the problem, the port itself is just too small. The guys at Kraftwerks (I think it was them, anyway) said you couldn't even fit a pinky finger into the intake port.

You aren't gonna flow much air through a straw, doesn't matter how smooth it is.

That being said, I think that with the proper fuel mods to support it and enough boost 200 whp is definitely achievable. Cheap? Naw. But fun as hell I'll bet.

 

if it won't breath on its own, just blow on it harder. lol I would love to pick up someones old l15a that did a k swap just to disect it and look it over.

 

amen. i just came up on two r18s at work cuz one threw a rod and another sucked up water.. im waiting for a fit toroll in with a hydrolocked motor and ill pull that thing apart in a heart beat lol

 

if/when you do. take pictures and post them up.

 

You could swap the L15A7 head onto our L15As

 

it depends on how different the l15a7 head is from the l15a if its not that different. it shouldn't be a problem to swap the heads unless the l15a7 heads design are radically different than the 15a where the heads would be a direct or near direct bolt on affair.