StwoK

 

He is talking about the F20C....S 2 K...Stookie

Other factors to be considered are R/S and head flow, valve angle and size, etc.

Mchuang I actually did mention the headflow differences in the other thread near the end. Ted and I were discussing it as I recall.

edit- https://www.evolutionm.net/forums/sh...ht=Honda+Power

 

Ahh, lol. My bad. All you have to do was say F20C!!! I have actually never heard it called that... and i'm all up in the honda ish. LMAO

The F20C is a great engine too, although a lot of people think the k20 was derived from it, it is not. The f20c head flows great too. But the head lacks VTC on the intake cam, which makes it inferior in design to the k20A2 head. What makes the F20C such a great motor is it's rod ratio, which promotes very high revs safely. The k20 can actually be run stock to about 9200rpms(which is the limit of the stock valve spring/retainers before valve float), but it's the rod ratio that kills this engine with ultra high revs in stock bottom end form.

I actually posted in a thread a couple weeks back on here about piston speeds at high RPM's on the K20A. It's the high revs(over 9000rpm) that kill these engines on stock bottom ends.

https://www.evolutionm.net/forums/sh...9&postcount=17

Look at the acceleration at TDC at 9500RPMs! it's amazing that the rods don't stretch even at a measly(for this motor) 8400rpms @ 4300g's.

CJ

 

Just because it lacks VTC does not make the s2k motor an inferior design that is all just a matter of opinion. Do you take into the account of the crappy rod bearing jounals of the k20, which are very narrow, which is why most people who do use this motor for professional racing actually have to get work on the crank to widen the rod journals to accept rods with a wider journal. What other honda vtec motor has this problem. None. So of course there are ups and downs to each motor. Also you forgot to mention that the k20 has cast pistons, vs the s2k using forged pistons and rods and that the there is no reliability in a k20 making 500hp on stock motor. I know the mark can be reached, but reliably not likely. I have personally witnessed a k20 making 500hp on the dyno and get some street and track time, but with 3 diff blocks because when one would blow the owner would go buy another k20 block instead of investing to build the block, but those motors have all blown up and not due to tuner error, the guy is a pretty good tuner and has a great track record(prefer not to mention names). The fastest all motor pro am car is a k series, Norris Prayoonto, but guess what, the crank is modified, because the rod journals on the K20 suck. Actually I dont even think Norris has a k20 crank, he uses a modified crank from an H22 if I can recall because they are wider. I dare you to take a k20 road racing that motor will die. The b series vtec version has never had this problem, nor has the s2k. As a matter of fact when I had my stock bottom end gsr motor in my si, with a built head,(Trying to make a poormans type R) I would rev that motor to 10000k every weekend for 2 yrs and not once did I have a problem with the rodbearings, even though there is more sidewall load on a b18c vs a k20 due to rodstroke. You can actually search the rsx forum, and you will see how many have had bearing failures. I stopped counting so many. K20 has potential to make good power, and eventually I would like to use one as a daily driver but it has a darkside too. As far as modding it for high hp, I would rather stay away from the headaches.

 

You are exagerating your claims by a lot about the crank. You sound just like the b-series guys when your trying to lay claim that the b-series is better.....blah blah.....sounds just like them, and they have been proven wrong over and over(this is such a elementary claim). I did mention that the K20 has cast pistons.....lol, this is why it is one of it's weak points, along with cast rods. Everybody knows that.

While your at it, search clubrsx.com key word "teamxrsx". You obviously have not been around in the k series community long.

Also, there is a ton of reliable K20's running around on stock blocks making 500+WHP, this is not debabtable. Anybody that knows anything about a boosted k20 should know that, it's very well documented. There are always going to be failures when people are pusing the envelope, not matter what engine you are talking about, but they are very hard to come by with the k20a2. You are basing one instance you have personllay seen by some unknown dood for fact about all k-series engines. Thats the sign of someone that does not really know that much about an engine, and is a F20 and b-series fanboy, which is fine, they are great engines, but a k20 they are not.

When the k series first came out, you guys were saying the same damn things....... it will never be a h22, it will never be a b18, it will never be a f20....lol I thought that kind of retoric had passed since it's been so long and it's a well known fact that the k20 is a stronger engine and more reliable. It's documented over and over and over and over and over again.

Oh yeah, and i have heard of very few rod bearing failures too, another exageration. You better be glad you didn't break a rod@10,000rpm(which i think is yet another exageration due to rod ratio on that engine), much less spin a rod bearing.

Anyway, good luck.

CJ

 

Itune you call me a b series fanboy, but you endorse the K-series like you designed it and actually I am more of a fan of the K20 than you think. But the only motor I really give a dam about is the 4g63. The only motor that could be 10 years old with 200000 miles and take a beating. Best performing 4 cylinder ever made hands down(my opinion). I would only use a k20 in a moderate application, not nothing extensive. I have a buddy who use to participate in the all motor class with prayoonto and was thinking about switching to a k series and I was there while he was talking to him, and he even stated that cranks are a problem when trying to spin them high. Now if anyone knows about a k-series its him considering he is the fastest all motor car in the country, and for some odd reason the k series crank was not good enough for his high revving all motor car so he uses an H22 crank. I searched teamrsx did not find much, maybe you can enlighten me, but do it in a pm, I would honestly like to see what you are talking about. I think we are swaying a lil off topic and would not like to get the thread lock due to my fault or yours.

 

sure can. check this out.

http://www.houston-imports.com/forum...d.php?t=335660

 

You didn't search my name hard enough. Although i didn't design the engine, i did a ton of research and development on aftermarket stuff for this engine, especially forced induction. Like i said, i was a kseries boost pioneer. I was responsible for debunking a lot of myths about this engine and myths about certain parts offerings as well.


I'm not taking that away from the 4G63, it's been around a really long time and has proven to take some serious abuse! I did not and will not debate this fact.


I'm sorry you feel this way, but this comment shows that you are very misinformed. By saying this, you are a very small minority. Most people that really know this engine would not agree with you.

What is your deffinition of "spinning the high"? we talking about 12,000rpms? 11,000? Very few stock cranks will not need to be modified to handle super high revs, no matter what crank is used. Very misleading comment. The stock k20 crank can handle 9500-10,000rpm easily, BTW. It's the other pieces of the rotating assmbly that cause there to be problems with ultra high revs man, on any engine. I have run 9500rpms for many many miles with my k20a2. I have over 500 dyno pulls on this engine and many track pulls and just general beatings. The engine has over 75k of hard boosted, high rev abuse.


His reason for using a H22 crank may not be what you think. Also, one theory on why the bearings are not getting enough oil is not nessicarily the k20a2 crank journals, but actually the oil pump spinning too fast and causing bubbles. Modifing the oil pump usually fixes this issue. The k24A2 crank actually has the same journal size as the H22, just so you know.


I don't believe you searched hard enough. Obviously there is going to be a lot of info to sift through, but if you are vigilant, you will see why i was a valued memeber in the boosted k-series world. I will PM you with all my accomplishments and accolades, if you are too lazy to look for yourself, or don't have time.(again there is a ton of stuff to look through). Or, if you like, just PM "JMBare", the clubrsx boosted forum's moderator....we both single handedly started a boosted revolution in the k-series world and debunked the infamous CN Guardian piggyback. Ask Doug Macmillan from Hondata about how well we know eachother and the work that i have done for him.

CJ

 

so if you put a better head on the 4g63 would it become amazingest?

 

the evo with a built k seris boosted motor would be the ultimate car.
the evo is a great car. its just the 4g63's head is so inefficeant and inferior compared to hondas.

 

How is it inefficient. Do you care to elaborate on that. Especially since the last Evo that Mitsubishi released has a very similar cam setup to the k series and flows very close on the intake side and more on the exhaust side so far as i have seen. What does inefficient actually mean in this case?

 

Well the only reason I mention these things Itune is because you say,"The k20 is a better motor than the f20 because the f20 lacks VTC". How does that make the
f20 inferior? That is like me saying the k20 is inferior to the 4g63 because it lacks an iron block. I am aware of the rod journals on a k24 also. That is why the tsx motor is highly sought after. The head of a k20 mated to a better block(for those who think bigger is better). I was only referring to the k20 though which is the motor you are referencing. I am a person that would like to see proof to back up your comments that is all, no harm intended. I mean anyone can say one motor is better than the other, but show me why, because I would love to become a believer. I am sure others would like to see why also. Once again though if I come across wrong excuse me, no harm intended, hell we have something in common and the reason we are both on the same forum and it aint the K20 lol

 

Wrong on all accounts.

 

the k 20 is superior to the f20c sk2 motor. a k seris will always make more power than a f20c if both of the motors were built. A sk2 makes 200whp stock and even built with bigger cams and such really strugle to make much more power. a k seris mildly built can make 250whp like nothing all motor.

also there are no benifits in a iron block compared to aluminum. There is no stress on the block itself. there is only stress on the sleeves. as long as the sleeves are iron thats all that matters. an iron block is just added and unnessary weight on the car. mitsu is just cheep and its cheeper to make an iron block compared to aluminum.

 

Wrong again on all accounts. No forces on the block, hahahhaha.

Anyways rod big end sizes came up. As per manleys catalog:

6 bolt 4g63 - 1.115"
7 bolt DSM 4g63 - 1.038"
B16A 92 up - 0.935"
B18C 94 up - 0.858"
K20 2002 and up - 0.780"

Big end rod bearing width is a pretty big deal. The wider the better and the harder it is for the crank to push through the boundary layer of oil making rod bearing to crank contact.

Even more alarming is the actual size of the K20 rod bearing (diameter) at 2.008" compared to 1.890" big end size shared by the b series AND the 4g63's. A larger big end size means that the surface speed between the crank and bearing at a given rpm is HIGHER for the rod with a bigger big end. Higher surface speeds lead to rpm related failures sooner. So if I were running a K20 motor I'd be running some thick *** oil, some fairly large "loose" clearances, keep the rpm's "conservative" and pray. Actually I'd do a custom crank with B series rods if even possible to get a wider rod bearing and smaller diameter big end to reduce surface speeds allowing both higher rod forces AND higher rpm's.

It looks to me like honda was trying to "narrow up" the K20 to fit a smaller package and in the process had to make compromises. The extremely wide rods in the 4g63 (specifically the 6 bolt) are a true testament of the motors outstanding design and durability for INTENDED TURBO USE!

Finally, anybody around racing motors (road racing, drag racing, street motors) knows that rod bearing failures are the most common problems. You can not spend enough time on this part of the motors design.