Lets Talk Honda Engines- Discussion Thread

[cb7pr]

I remember a Honda Tuning issue that did an "unleashing the HP" type of write up on the TSX and with relative ease they got 186WTQ and something like 220WHP with just a header, intake, tuning, and VTC adjustment.

Phearable ECU reflash.

[owequitit]

Some inherent advantages of the K-series. I will compare DOHC VTEC to DOHC VTEC, so the K series with VTEC on the intake only side will be left out, as that isn't quite apples to apples.

1) The K series was lighter and slightly smaller than the B series. So, H series power and torque (slightly less - slightly more, depending on displacement) in a package that is lighter and more compact than a B series. Not a bad deal really.

2) It has better bottom end geometry in most respects. At 2.0L it is a square design with an 86mm bore and 86mm stroke. This makes it more rev happy than the B series, and to an extent the H series as piston speeds are lower.

The block is smaller, lighter and has a lower center of gravity by virtue of the fact that the smaller versions have no balance shafts. In the engines WITH balance shafts, they are smaller, and located down in the sump, so the CG is lower and total mass is probably lower as well.

The K series has a better skirt design. Whereas the B series, F series, and H series all used a reinforcing girdle to stabilize the crankshaft maincaps, the K series actually uses a split crank case. This is better for high RPM's, long term durability, and NVH characteristics.

The K series features a timing chain rather than a timing belt which results in less change in relative angle between the cams and crank.

3) The head in the K series merged most of the advantages of VTEC with most of the advantages of Honda's SOHC designs. This came mainly in the form of valve angles and port design which is simply amazing for a production engine. The ports in stock form are pretty much superior to any stock Honda engine previous to this one. The valve angle allows more efficient combustion, piston design and probably larger lifts than earlier VTEC engines, which had more valve angle.

The K series head also features roller rockers which reduce valvetrain friction. Since valvetrain friction can account for something like 20% of the total friction, this is a GREAT area to save on. In addition to incorporating roller rockers, the valvetrain is also much more compact.

The stock valvetrain in a K20 is good to around 8600-9000 RPM. If you upgrade the cams, a simple change of springs and retainers is in order.

Obviously, one main feature difference between the K and and H is the fact that the K series features Variable Timing Control on the intake cam. This nets some additional top end power, as well as a much broader torque curve by virtue of the fact the cam angle is pretty much always optimized for the RPM.

The K also has coil on plug ignition, which is more accurate, and more tuneable than a distributor type ignition on the H series.

The other thing to keep in mind, is that the K series is offering similar performance in a smaller package, while using single stage intake runners. If you were to couple a dual stage IM similar to the H series, you would see a pretty good torque gain. If they implemented VTC on the exhaust cam, you would probably see an additional 3-4%. I think the dual stage IM would be worth about the same, so you figure they could probably obtain an additional 6-8% torque on a K20, which would amount to an additional 8-12 lb-ft of torque over most of the RPM band.

In short, the K series enjoys a superior head design, less friction, more compact design, lighter weight, better block construction, better capability to control the combustion event etc. It is also relatively simple compared to what it could be as it does not feature dual stage IM's (there are some exceptions), VTC on the exhaust cam, or direct injection (that is another topic entirely). It is smoother, more rev happy, has a more linear powerband, and is pretty much as efficient, while meeting increased emmissions requirements.

[h22sparkle]

the k-series is well known but i honestly think its due to too much hype from its fanboys to boot. I say the h is slightly more simpler but id like to know more info about the j-series. In all honest I really think its about the money when it comes to the perfomrance.

[owequitit]

the k-series is well known but i honestly think its due to too much hype from its fanboys to boot. I say the h is slightly more simpler but id like to know more info about the j-series. In all honest I really think its about the money when it comes to the perfomrance.

The K series is well known because from a technical standpoint it is better. Period.

Yeah, because the FACTS of the technology are TOTALLY fanboish...

[h22sparkle]

j-series does seem promising though. j37 in a cb7 interesting. 300hp and 274 tq so you figure 280whp and 250 something wtq that would be nice in a cb chassis surprise em everytime.

[owequitit]

j-series does seem promising though. j37 in a cb7 interesting. 300hp and 274 tq so you figure 280whp and 250 something wtq that would be nice in a cb chassis surprise em everytime.

I am pretty sure the J series also has a ton of extra power locked up. Usually, exhaust and intake upgrades are good for 30+WHP and their torque curve kicks ass. They are at 90% of peak torque by 2,000RPM and they keep it there until 6K. They are flat as Kansas.

But, I think with the limitation of the front suspension and FWD on a CB, traction would be an issue. It would also move the weight distribution foward, even though it wouldn't increase total weight all that much most likely.

[h22sparkle]

I am pretty sure the J series also has a ton of extra power locked up. Usually, exhaust and intake upgrades are good for 30+WHP and their torque curve kicks ass. They are at 90% of peak torque by 2,000RPM and they keep it there until 6K. They are flat as Kansas.

But, I think with the limitation of the front suspension and FWD on a CB, traction would be an issue. It would also move the weight distribution foward, even though it wouldn't increase total weight all that much most likely.

the torque, weight and slightly stickier tires w/lsd should counter that though with perhaps some bolt-on's .

[rezist09]

Architecturally, the K is superior to the H in pretty much every way imaginable. The more you crack into them, the more apparent that becomes.

The DOHC VTEC K series don't really need any help in the head department until around 300WHP NA. So it is just a matter of springs, retainers and cams.

Also, the 300HP level in a K20 is pretty much achievable with a stock IM (the RBC), some cams, springs + retainers and a well designed intake and exhaust system with a tune to go with it. Absolutely nothing exotic is required.

Even Honda in their own CTR engine is making 225HP and about 160 lb/ft of torque. That is 112.5 HP/liter, which is actually very impressive considering the technology that the K series does NOT have.

It is just such an amazing engine from a stock OEM perspective it isn't funny. As usually, Honda builds a really kickass engine and then chokes it down with restrictive intake and exhaust, as well as conservative tuning. The stock bottom end will do 9000-9500 RPM without issue, the stock valve train will do nearly 9,000, and it will easily make power that high with the right simple changes. And, they relish every minute of it. Even to a greater extent than the B series and H series, the K series feels like it just wants another 1500RPM when you slam the rev limit with it being so smooth and so eager.

Boost it and they get insane. 400WHP doesn't seem to be much of an issue on a stock block.

guy is right making boost is easy for k's some peep have base rsx boosted on stock bocks making 300whp i know i was doing that with my rsx

[owequitit]

guy is right making boost is easy for k's some peep have base rsx boosted on stock bocks making 300whp i know i was doing that with my rsx

Look up AJP's videos on youtube. They have stock blocks quite a bit higher than that, with higher compression.