How to build a "reliable" lsvtec/b20vtec

[bambam]

Originally Posted by Oldskool teggy do you think that the stock rods with arp rod bolts and acl bearings will take 9500 rpm needed on skunk stg 2 and bc stg 4? or is 9k the limit you take yours to? Well, obviously everyone's opinion is going to be different on this.... here's mine: Everyone argues about how the LS bottom end isn't rev-friendly. And they're right; in stock form it isn't. It uses the same rivet-sized rod bolts as the sohc motors. It also has a disadvantage in the bearing design, as it doesn't use the Tri-metal design as the GSR/ITR/CTR's bearings are. I've alleviated that problem. I've upgraded to the Larger ARP rod bolts, as well as the Tri-metal ACL bearings, which help in oil retention at the higher RPM's. Now, before anyone mentions the R/S ratio....blah blah blah. The GSR/ITR/H22 R/S ratio is 1.58 as compared to the LS's 1.54...do you really think that is what contributes to the stock 1800 RPM redline difference? Somewhat....but the answer is "no". The LS rods aren't any weaker either. Also, the B18a/b motor had a totally difference purpose, which is evident in it's design. Smaller cams, non vtec, different water pump, different sizing on the intake and exhaust, smaller ports, more displacement, etc. It was marketed to a different crowd. I take my LSvtec motor to 8600. Rarely do BC4's or S2S2's carry power past 9k without extensive flow work like ITB's, head port work, header design, etc.....at least in the dyno's i've seen that's how it usually works. BC4's and S2S2's don't NEED 9500 rpm. In fact, the BC4's outperform nearly every other cam on the market up to the vtec engagement point. I think the BC4's compliment the LS bottom's torque curve properites, as well as the higher piston speeds the lower R/S ratio produce. When comparing a lower R/S ratio block to a higher R/S ratio block, you should know that the lower R/S ratio block will have higher piston speeds at the same RPM. This is also an advantage, as it "pulls" air harder into the cylinder. What I am saying, with all other things constant, the 1.54 RS ratio will pull in more air at a given RPM than the 1.58 or 1.76 RS ratio. But, a lower R/S ratio will put more stress on the crank and bearings...that's a proven fact. As long as you build a block to handle the added stress, then the lower the R/S ratio, the better. Honestly, my bottom end wouldn't worry me if and when I decide to take it to 9500 rpms. I'd be more worried about the valve spring/retainer combo one decided to use to carry that RPM. Also, in any motor, the higher the RPMS, the better the tune needs to be due to the excessive heat. With that said, there's also the water pump issue. Vtec blocks have more teeth on the water pump. Why's that? To HELP cooling at higher RPM's, where the heat exchange needs to be greater. There's alot more factors than appear on the surface hear when comparing an LS's safe revability vs. a GSR/ITR/CTR. I've sat my motor at 8600 on the highway for nearly 45 seconds once.....redlining fifth gear the whole time. I trust my motor, and I trust my builder: me. I've also got a link that shows the effects of changing the RS ratio. By using a 1cm longer rod, they only effectively raised the redline by 1.5%...a whopping 120 total extra safe RPM...not even anything worth mentioning is it? There is alot of mis-information floating around on this board about RS ratio's and how they affect a motor. People read something on here about RS ratio...and they adopt it right away as "law", and then start regurgitating (sp?) it to all of their friends verbatim...what a shame. I suggest anyone wanting to learn more about RS ratio's and how they affect every aspect of a motor, do the research and form your own opinions. Modified by bambam at 3:55 AM 7/6/2006

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[killerpenguin21]

awesome info

b16 ctr pistons are a direct fitment into an ls lock or so ive read?...but what crank are you using out of curiosity? (im guessing the ls?)

[bambam]

Originally Posted by killerpenguin21

awesome info

b16 ctr pistons are a direct fitment into an ls lock or so ive read?...but what crank are you using out of curiosity? (im guessing the ls?)

You need to shave about 1mm off the small end of the rod to fit GSR/ITR/CTR pistons on LS/B16 rods.
As for the crank...yes, I am running an LS crank. That's what makes this an "lsvtec".

[hialeahzbg]

i have stock 01 jdm itr cams in my b16 head...should i get aem cam gears?

[jackiechan]

good shit

[hialeahzbg]

so cam gears are needed when doing an lsvtec? ive had mine for about 3 years now and it runs just as hard as it did before...should i get cam gears even tho i have stock jdm itr cams?

[bambam]

Originally Posted by hialeahzbg

so cam gears are needed when doing an lsvtec? ive had mine for about 3 years now and it runs just as hard as it did before...should i get cam gears even tho i have stock jdm itr cams?

Should you? yes. Is it necessary? no.
When doing an lsvtec/b20vtec, it is impossible to get the timing perfect (valve timing). But, it's nothing to really worry about. It's only off by a fraction of a tooth. If you had adjustalbe cam gears, you'd notice that it is off by about .5 degrees on each cam....if I remember correctly.

[hialeahzbg]

so getting adjustable cam gears will improve timing resulting in more performance?

[TheLastSpartan]

How do you feel about adding on a girdle for the bottom end?

[bambam]

Theoretically, yes. But, every motor is different. I'm sure the power increase is not something you can "feel".

[bambam]

Originally Posted by TheLastSpartan

How do you feel about adding on a girdle for the bottom end?

Well one thing's for sure....it WONT hurt. But, it's not mandatory. That's all I can say about it as I've never used one personally. I try to refrain from giving opinions on things I have not done/tried myself.

[xDicktonesx]

Originally Posted by bambam

There is alot of mis-information floating around on this board about EVERYTHING and how they affect a motor. People read something on here about ANYTHING...and they adopt it right away as "law", and then start regurgitating (sp?) it to all of their friends verbatim...what a shame.


Modified by bambam at 3:55 AM 7/6/2006

modified

[RC000E]

Originally Posted by sheepey

quick question, why dou you say to tq the head down with 10 more than ARP says when not using ARP lubes?

The difference is that ARP has verified the necessary torque required to get optimum clamping force when using the specific lubricant they provide. Friction between threads, as well as the the nuts friction with the head surface once in contact, can alter that number. Therefore, different viscosity and types of lubricants will require different torque numbers, as friction between threads will vary.

This is why you should always lubricate all threads and contact surfaces, as well as use whatever lubricant is provided if possible, then torque in a very consistent motion. You want to very evenly "load" the stud or bolt in question in order to achieve the torque number your after. That torque number should theoretically elongate the fastener in order to achieve the clamping force, compression, etc. required.

[Chris Benoit]

I have a quick question. I am running a stock head stock block b20vtec.

It runs great when I am just driving from point A to point B, never over heats, doesn't studder, and idles fine.

Where I run into trouble is if I let it crossoever into VTEC, after that it doesn't want to idle and will die. If I restart the car it will run perfect again. What could be the cause of this?

[RC000E]

Originally Posted by bambam

When comparing a lower R/S ratio block to a higher R/S ratio block, you should know that the lower R/S ratio block will have higher piston speeds at the same RPM. This is also an advantage, as it "pulls" air harder into the cylinder. What I am saying, with all other things constant, the 1.54 RS ratio will pull in more air at a given RPM than the 1.58 or 1.76 RS ratio. But, a lower R/S ratio will put more stress on the crank and bearings...that's a proven fact. As long as you build a block to handle the added stress, then the lower the R/S ratio, the better.

Modified by bambam at 3:55 AM 7/6/2006

Since this thread is going to take on a benchmark status then I have no choice but to give readers the benefit of an additional opinion here.

Stating that a shorter r/s pulls air (I see the quotes there...dont' worry...just clarifying though) harder into a cylinder isn't really accurate. You have a pressure differential therefore air pressure forces itself into the cylinder in order to replenish an area of lower pressure.

Granted, that faster piston speed can create a larger "demand" more quickly, but the limitations of the "feeler" rocker arms (and therefore cam ramp angle limitations) don't allow valve opening quickly enough to go as far as to say it's better. If it did though, due to the fast piston speed (from larger stroke) and limitations mechanically, peak cylinder pressure will occur and will be wasted to loading the wristpin, rod end, and bearings versus to rotating the crankshaft. The longer rod/stroke loads the crank more tangientally, therefore more efficiently.

Saying that changing the rod stroke hardly effects redline as a defense to spinning an LS/vtec like crazy really doesn't make sense to me. No doubt, your correct, making the rod/stroke a perfect 1.74 (somewhere around there) doesn't do much for an LS/vtec rpm wise. The reason is, rod/stroke isn't the determining factor in piston speed. Piston speed is the result of mainly stroke...that charasteristics of that mean speed is then influenced by rod length and, of course bore.

B18C1 stroke (stroke 3.433x8000 rpm)/ 6= 4577.33 fpm piston speed at that rpm.
B18A1 stroke (3.504x8000)/ 6= 4720 fpm

This difference isn't that large, but internally the motors are very different, which is why there is limitation. 4577.33 fpm out of the GSR is really incredible considering that speed has blown up domestics for alot of years. The GSR though has the rod bolts, bearings, girdle, and block structure to support those speeds, the LS does not. In addition Honda has done well, as you've pointed out, to keep engines cool with the floating cylinder design.

Also realize that the GSR's bore/stroke is favorable to the LS bottom ends...granted very slightly, but nevertheless favorable.

The point is, the LS stroke gets you more torque...it's a longer stroke. Pack a longer stroke in the same height block and rod length has to go. As a result, rod, piston, cylinder wall stress increases if you want to spin it fast. If you build it to combat those stresses then your fine. The rod length though can certainly help you in allowing the motor to breathe at high rpm and use cylinder pressure more effectively, which should be a primary factor driving one to achieve a better rod/stroke. Short rod motors can sometimes out-accelerate the flame front which will show as far a brake mean effective pressure goes.

What it all comes down to is what Larry Windmer has often stated...the best motor is merely the best series of compromises. I'll add to the end this time....the best motor is merely the best series of compromises, a series that most young Honda builders never come close to achieving.

Good thread so far O.P.

[bambam]

Originally Posted by John Cutter

I have a quick question. I am running a stock head stock block b20vtec.

It runs great when I am just driving from point A to point B, never over heats, doesn't studder, and idles fine.

Where I run into trouble is if I let it crossoever into VTEC, after that it doesn't want to idle and will die. If I restart the car it will run perfect again. What could be the cause of this?

No check engine lights? I'd be willing bet that your motor is getting "stuck" or staying engaged on the vtec lobe. I've seen this happen before. Unless it's a mechanical problem, it sounds to me like a wiring problem. Switching the Oil pressure sensor wire and the vtec solenoid wire will do what you described above.
If it's not that, it's something mechanical w/ the vtec activation system.

[bambam]

Originally Posted by RC000E

Since this thread is going to take on a benchmark status then I have no choice but to give readers the benefit of an additional opinion here.

Stating that a shorter r/s pulls air (I see the quotes there...dont' worry...just clarifying though) harder into a cylinder isn't really accurate. You have a pressure differential therefore air pressure forces itself into the cylinder in order to replenish an area of lower pressure.

Granted, that faster piston speed can create a larger "demand" more quickly, but the limitations of the "feeler" rocker arms (and therefore cam ramp angle limitations) don't allow valve opening quickly enough to go as far as to say it's better. If it did though, due to the fast piston speed (from larger stroke) and limitations mechanically, peak cylinder pressure will occur and will be wasted to loading the wristpin, rod end, and bearings versus to rotating the crankshaft. The longer rod/stroke loads the crank more tangientally, therefore more efficiently.

Saying that changing the rod stroke hardly effects redline as a defense to spinning an LS/vtec like crazy really doesn't make sense to me. No doubt, your correct, making the rod/stroke a perfect 1.74 (somewhere around there) doesn't do much for an LS/vtec rpm wise. The reason is, rod/stroke isn't the determining factor in piston speed. Piston speed is the result of mainly stroke...that charasteristics of that mean speed is then influenced by rod length and, of course bore.

B18C1 stroke (stroke 3.433x8000 rpm)/ 6= 4577.33 fpm piston speed at that rpm.
B18A1 stroke (3.504x8000)/ 6= 4720 fpm

This difference isn't that large, but internally the motors are very different, which is why there is limitation. 4577.33 fpm out of the GSR is really incredible considering that speed has blown up domestics for alot of years. The GSR though has the rod bolts, bearings, girdle, and block structure to support those speeds, the LS does not. In addition Honda has done well, as you've pointed out, to keep engines cool with the floating cylinder design.

Also realize that the GSR's bore/stroke is favorable to the LS bottom ends...granted very slightly, but nevertheless favorable.

The point is, the LS stroke gets you more torque...it's a longer stroke. Pack a longer stroke in the same height block and rod length has to go. As a result, rod, piston, cylinder wall stress increases if you want to spin it fast. If you build it to combat those stresses then your fine. The rod length though can certainly help you in allowing the motor to breathe at high rpm and use cylinder pressure more effectively, which should be a primary factor driving one to achieve a better rod/stroke. Short rod motors can sometimes out-accelerate the flame front which will show as far a brake mean effective pressure goes.

What it all comes down to is what Larry Windmer has often stated...the best motor is merely the best series of compromises. I'll add to the end this time....the best motor is merely the best series of compromises, a series that most young Honda builders never come close to achieving.

Good thread so far O.P.

Wow, great post. Lots of fact, not opinion in there.

[hialeahzbg]

2day while installing my hondata intake manifold gasket i put it on top dead center and the 2 little lines on the cam gears werent facing each other perfect....it was a little off id say about 1mm off...does that make a difference? im i losing performance? with aem cam gears will it correct it stay that way? i love my lsvtec...i really didnt feel a difference out of my hondata gasket...i noticed the gasket is bigger than the actual holes on the head...

[JERKSiRcoupe]

Originally Posted by black cx

very good info

[bambam]

Originally Posted by hialeahzbg

2day while installing my hondata intake manifold gasket i put it on top dead center and the 2 little lines on the cam gears werent facing each other perfect....it was a little off id say about 1mm off...does that make a difference? im i losing performance? with aem cam gears will it correct it stay that way? i love my lsvtec...i really didnt feel a difference out of my hondata gasket...i noticed the gasket is bigger than the actual holes on the head...

It will make a difference, just probably not something you can feel from the "butt" dyno. Adjustable cam gears would fix that. It doesn't have to be AEM cam gears....there's tons of different manufacturers of cam gears for the bseries.

[hialeahzbg]

but the new aem ones have 5 screws...i havent seen one that adjustable.

[bambam]

Originally Posted by hialeahzbg

but the new aem ones have 5 screws...i havent seen one that adjustable.

There are plenty of adjustable ones:
Buddy Club, STR, Golden Eagle, AEM, Skunk2, Toda, ST. Corsa, Rage, JE, Jun, UR, Full-Race, etc.......

[hialeahzbg]

how do i install cam gears?

[xDicktonesx]

Originally Posted by hialeahzbg

but the new aem ones have 5 screws...i havent seen one that adjustable.

eh....the more screws the more adjustable they are?

[bambam]

Originally Posted by xDEFTONESx

eh....the more screws the more adjustable they are?

WTF?
Cam gears with more screws were just developed over time to better prevent the cam gear from slipping.


Modified by bambam at 12:25 AM 7/10/2006