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Discussion Starter #1
what internal mods are possible for engines? ive heard of ported heads and forged pistons but what else is there? and do they really help?
 

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I'm getting stiffer springs for my cylinder heads, and valve guides of a stronger metal, but I'm having a machine shop do it, and I couldn't begin to explain head work, because I just don't do it much. Basically the stiffer springs allow for higher RPM range, because the valve is able to close faster.

I'm running an SDS system, and won't be using a factory PCM, so I can adjust the governed redline. You would have to do something similar, or the head work is useless.

Other than port-matching and polishing, there's not much else you can do to the head. If you're doing a naturally aspirated engine, you can mill the heads down a little to increase compression, but I'm boosting and don't want to do that.

The stronger forged pistons only help if you're boosting, where you really need the extra strength. All porting and polishing does is reduce turbulence and increase flow, which is good for N/A, but is pointless, I think, on a boosted application.
 

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With the N/A engine basicly the only things you can do is to port the head, increase the compression either with new pistons or by shaving the head and get better cam shafts. every other modification will work with these to make your motor hold together
 

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Discussion Starter #6
so basically if someone is planning on boosting (turbo right?) it would be better to get forged pistons and stiffer springs for the cylinder head and stronger valve guides?
 

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yes that is correct but not only pistons you would also need forged conrods and new piston rings as well, plus an aftermarket ecu as the stock1 wont work. It isnt very practical to go turbo as there are no kits available and you have to do everything custom. this would be very expensive if you cant do the work yourself.
 

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Forged pistons are BETTER when boosting (and I do mean turbo), because the extra strength helps for high boost, you need stronger parts. But I'm actually not doing any internals this year, other than the head work. You can boost any Honda engine basically from stock, and only run a few pounds(6 to be safe, maybe up to 8 psi).

The stronger springs will help (boost or not) to achieve higher RPM. Again, you don't necessarily 'need' the stronger valve springs, unless you're planning on revving high. The 2.7 has great torque at lower RPM, and high revving doesn't really suit for natural aspiration (non-turbo). The only reason I'm doing springs, is because the turbo is going to help with the torque-loss at higher engine speed, so I may tune it do an extra 500-800 RPM, but I won't do this until I have it on a dyno, so I can see if the higher rev helps me any.

The valve guides I am having done because, in my experience, I have seen the Legend engines "waller out" (southern terminology) the guides, which eventually leads to guide seal leakage, which contributes to the smoking-at-idle problem that these Legends tend to do.

Like Muffo said, it's expensive. I'm doing most of it myself, and I'm already over $5K in parts. Of course, this is between the turbo components, engine management, stainless exhaust sections, water-air intercooler system, E-V-E-R-Y-T-H-I-N-G. Also, I didn't opt to get a cheap turbo. I got a Garrett GT30 series, which is pricy. There is a place online, forcedairtech.com I think, that sells a kit, but you have to bring them the car, have them install it. $4500 last time I looked, but it's a small turbo, inefficient system (from what I can tell), and doesn't include engine management system, or even bigger fuel injectors. The guy who got one didn't get much of a HP gain with it either.
 

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Forged pistons are BETTER when boosting (and I do mean turbo), because the extra strength helps for high boost, you need stronger parts. But I'm actually not doing any internals this year, other than the head work. You can boost any Honda engine basically from stock, and only run a few pounds(6 to be safe, maybe up to 8 psi).

The stronger springs will help (boost or not) to achieve higher RPM. Again, you don't necessarily 'need' the stronger valve springs, unless you're planning on revving high. The 2.7 has great torque at lower RPM, and high revving doesn't really suit for natural aspiration (non-turbo). The only reason I'm doing springs, is because the turbo is going to help with the torque-loss at higher engine speed, so I may tune it do an extra 500-800 RPM, but I won't do this until I have it on a dyno, so I can see if the higher rev helps me any.

The valve guides I am having done because, in my experience, I have seen the Legend engines "waller out" (southern terminology) the guides, which eventually leads to guide seal leakage, which contributes to the smoking-at-idle problem that these Legends tend to do.

Like Muffo said, it's expensive. I'm doing most of it myself, and I'm already over $5K in parts. Of course, this is between the turbo components, engine management, stainless exhaust sections, water-air intercooler system, E-V-E-R-Y-T-H-I-N-G. Also, I didn't opt to get a cheap turbo. I got a Garrett GT30 series, which is pricy. There is a place online, forcedairtech.com I think, that sells a kit, but you have to bring them the car, have them install it. $4500 last time I looked, but it's a small turbo, inefficient system (from what I can tell), and doesn't include engine management system, or even bigger fuel injectors. The guy who got one didn't get much of a HP gain with it either.
If i remember it did include a pigy back computer, but i also think they aren't making this anymore so that option is out and it wasnt a ver good one as has been pointed out. If you want to go turbo you would either have to have a shit load of money to through at it or be quiet good around a car and do it all yourself and still have at least about 5 to 6k minimum to do it seriously
 

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Can't wait for the turbos guys. :bowdown:

The 2.7 has great torque at lower RPM, and high revving doesn't really suit for natural aspiration (non-turbo).
I disagree with this part. If it's tuned correctly it can make more power by revving higher ie; any Honda Type R lol, F1 racecars, etc. Honda takes small engines that only make so much torque and make them work very hard to spin at high rpms which results in sizable hp numbers. This makes sense because hp equals work done over time, if they make them work harder(higher rpm) and harder the engine will make more and more power. But, it would also need more aggressive cams to open the valves up long enough for high rpm speeds to be beneficial for more airflow to the pistons, and the con rods and pistons would also need to be forged to handle more stress of spinning faster. This is one of two ways for an N/A motor to make more power, the other way is larger displacement.

Another internal engine mod is bore and or stroking the motor. To make a larger diameter bore for the cylinders the cylinder linings would be bored out and larger diameter pistons w/ matching rings would be used. To stroke the motor would mean a longer throw crankshaft. There aren't any bore and stroke kits for the Legend that I know of so everything would be custom(big $), but the cylinder bores in the c27 are prolly just about as big as they can be without making the cylinder walls too thin. If they can be bored larger then, with tuning it would most likely give the motor more low end and mid range torque as well as some hp, but if it's stroked it wouldn't be as rev happy.

So like Muffo and Chopped said FI and higher rpm would give more power as well as larger displacement, all requiring beefed up internals. Hope this helps, OP.
 

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There is a stroker kit available from paeco but it is way over priced. As the honda motors are open deck so they cant be bored much. the price of the stroker kit goes a long towards a custom set up so it isnt practical
 
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