Reference: LS/CRVTEC info

iamgod

Banned
since i am tired of seeing threads about this, we should put ALL info regarding these swaps here

"LS VTEC and Thoughts on Rod Ratio Affecting Engine Combination
Here's a recent thread I was involved in that captures some basic relationship concepts you may want to discuss:



quote:
--------------------------------------------------------------------------------
Original Question Posted by Pollux

I heard that you can change a non-v engine to one with it, with a "VTEC"
block? Does this mean you would basically need to do an engine swap? Has anyond done this? Can someone explain to me what would be involved and what the cost would be?
--------------------------------------------------------------------------------




quote:
--------------------------------------------------------------------------------
First Reply by BlackGSR to Question

basically taking off your old head and replacing it with a vtec head

--------------------------------------------------------------------------------





quote:
--------------------------------------------------------------------------------
Originally posted by BlackGSR

basically taking off your old head and replacing it with a vtec head

--------------------------------------------------------------------------------



I wish it was that easy. I guess the search function doesn't have anything on LS VTEC eh? or did you not try to look there first? I'm sure we covered this a lot in the past.

Anyway, I suggest you check out these sites:

http://www.c-speedracing.com/howto/lsvtec/lsvtec.html

http://www.angelfire.com/sc/thuspeed/lsvtec.html

http://www.geocities.com/MotorCity/...437/lsvtec.html

the c-speedracing site goes through most of the salient points about the process of putting the combination together.

the key to this setup is WHO does it ....not the parts you should get which is what most novices focus on only, not realizing the impending headache they will face from an improper install.

you need to find a very good machine shop locally who is precise and has a good rep for doing things to spec dead-on (like blueprinting) with aluminum heads and blocks (not just iron domestic blocks). You have to
plug the VTEC oil passage in the VTEC head (usually welding the plug in is better than just using a bolt plug) and then machine the plug down flush with the cylinder head's deck surface. Secondly, since the LS block dowel pins and the VTEC head's dowel pin holes are not aligned, the machine shop must redo the dowel pin holes by slotting them to line things up properly.

The main problem with this setup is, if machining & installing are done improperly by an inexperienced or incompetent shop, you will end up with oil leaks and coolant leaks, since the ducts for oil and coolant in the
head and block are not aligned up...they were never meant to be put together at the factory in the first place and they have to "make" them fit with adjustments at the machine shop.

I always tell LS owners that you can get much more power reliably ,if you invest in a turbo and getting the correct anti-detonation parts , instead of running an LS VTEC.

To run faster than a GSR or ITR with i/h/e, you must upgrade the pistons for higher compression in the LS block. My friend Chistian Gaines runs an LS VTEC with 11:1 CR and makes over 185 peak whp with Type R cams. Chris used to visit us over at Superhonda and gave me good advice.



Most beginners mistakenly think the VTEC head allows them to rev higher.

The rod ratio in the LS VTEC is still the same as the LS...a low 1.54. This does not help your cause in revving higher. I explain why elsewhere, if you do not know what rod ratio means and it's implications on the redline. Beginners often think that the head and VTEC gives them a license to rev higher, when in fact, the rod ratio is what allows you to rev higher safely and reliably. The head just breathes better and VTEC allows variable valve lift/duration to get a peaky powerband in a 4 cylinder engine and at the same time, get decent driveability in the low-mid rpms....that's all...having VTEC is only one part of being able to rev higher...NOT the entire reason.

These concepts don't just apply to the 1.8L LS VTEC . You can apply them to a B20 VTEC which is a CRV bottom end or block (also has the exact same rod length & stroke as the LS!) with any Bseries VTEC head (it also needs the rear dowel pins aligned and the head oil duct shut by a machine shop). You don't rev a stock block 2L B20 VTEC past 8000 rpm either.


If you know of a good local shop then you may still want to look into
doing it...I also recommend www.drtracing.com who has done several of these reliably .


quote:
--------------------------------------------------------------------------------
Originally posted by 20lb teg

Hey Tuan, what effect does boost have on Rod Ratio's like for instance how much boost could that 1.54 r/r on an LS handle?? Is their like a formula of some sort to determine an estimated boost level or pressure level per point of rod ratio. This is a very important question in my mind because now I am reboosting my teg and when I redid my bottom end I was running low on funds and only had enough for pistons, so rods was where I sacrificed...

My setup is with JE forged 8.5:1 C/r but the rods are stock... Now I've seen some break/bend as low as 9 but others doing it on the track up to 20...! (On race day only with 107 leaded race gas) But my question still is, with JE/Forged pistons built for 25 psi of boost and stock LS rods and a newly built bottom end massaged and blue printed to exact specs what can I expect to run

A.) daily, but also
B.) On the track with 107 leaded...

Thanks for the help.
--------------------------------------------------------------------------------



rod ratio is calculated by taking the connecting rod length and dividing it by the crankshaft's stroke.

A good rod ratio is considered to be 1.65-1.77. Some people say the ideal rod ratio is 1.75:1 or 1.77:1. Guess what? the Civic b16a 's rod ratio is 1.75:1 and the CTR b16b is 1.86:1. Co-incidence? I don't think so. Honda has lots of race engineering experience with high revs in it's Superbike and Formula 1 N/A engines...like 18,000+ rpm. They trickle this knowledge and tech down to us common folk in a street car...cool huh?

Unfortunately, the integras got a low or short rod ratio: b18b 1.54:1 and B18C 1.59:1...not ideal.

So what is the importance of rod ratio anyway?

rod ratio describes piston geometry (3 things):

1. piston speed away from TDC and BDC
2. piston dwell time at TDC
3. the amount piston sideloading against the cylinder wall as the piston travels up and down the swept volume.

So rod ratio can affect how high you can rev, since a low rod ratio places more side loads on the wall.

The rod ratio in a naturally aspirated engine affects how well the cylinder is filled and dictates cylinder head port size. The faster the piston pulls away from TDC on the intake stroke means you can get more suck to fill the cylinder. How fast the piston transitions or flip-flops from squeezing the exhaust gas out at TDC for the exhaust stroke to dropping down and begin filling on the intake stroke (i.e. TDC dwell time) affects your cam overlap and cylinder filling.

low rod ratio engines have short piston dwell times at TDC and fast piston speeds away from TDC (or faster piston speed dropping down on the intake stroke compared to a long rod ratio). So a low rod ratio motor generates high flow velocities for filling through the intake port at low-mid rpm. These engines like bigger cylinder head intake port sizes compared to a long rod ratio motor like the Civic Si's b16a.

Low or short rod ratio ALL MOTOR engines like a cam with more lobe separation angle, more duration, and more cam overlap, since it has short piston dwell time at TDC and needs help scavenging in fresh air/fuel.

This all has to do with revving ability, proper intake port sizing, and cylinder filling IN AN ALL MOTOR SETUP which depends on passive filling using lower pressure in the cylinder (called pressure gradient) compared to the atmospheric pressure (14.7 psi). In turbos and SC's, you push in the air to fill the cylinder and so rod ratio plays a very MINOR role in cylinder filling.

The importance of rod ratio in a boosted engine relates to how efficiently the inert burnt exhaust gases are removed from the cylinder after combustion. The piston speed away from BDC to push the exhaust gas out is important. Remember exhaust gases aren't burnt twice and cannot make power and so if they aren't removed, they just take up space in the cylinder ... preventing room for fresh air/fuel from coming in to do their job. Burnt exhaust gases are like unwanted tenants not paying rent: you want to evict them from the cylinder."
 

iamgod

Banned
"Short piston dwell time at TDC is less important in a boosted engine because you don't want big cam overlap. More cam overlap here would cause some of the boost to shoot over into the turbo manifold instead of going into the combustion chamber (assuming the boost pressure is higher than the exhaust manifold pressure). You don't need big overlap cams to help filling. In fact, boosted engines prefer big lift but short duration and overlap.

So a low rod ratio actually helps a boosted engine, since the piston speed away from BDC is higher than in a long rod ratio engine (to help evacuate the extra burnt exhaust gases) and the importance of dwell time on filling and cam selection is less important for filling.

JUST REMEMBER: don't rev the sh*t out of a low rod ratio engine (all motor or boosted)...the shorter rod ratio still causes the piston to sideload the cylinder wall harder causing more risk of a piston going through a wall, the higher the rpms go (keep it under 8100 rpm).

If you want to read more on rod ratio, check this site out:

http://victorylibrary.com/tech/crod-c.htm



quote:
--------------------------------------------------------------------------------
Originally posted by daNattyFatty

....but ls/vtec engines tend to put out more hp and torque than a
regular vtec engine. it makes for a good all motor set up

--------------------------------------------------------------------------------



the LS bottom end has a lower rod ratio than the GSR or ITR bottom end.

as the rod ratio on a naturally aspirated (i.e. No Boost) engine becomes lower or shorter, low-mid rpm hauling power increases.

you see the peak torque shift to a lower and lower rpm, as the rod ratio drops. This is probably why Honda chose a shorter rod ratio with a higher displacement on the integras compared to the civics.

As you decrease displacement to 1.6L on a civic , peak torque , as an absolute value, becomes smaller and you have to rely upon higher rpms to generate horsepower, instead of depending on torque. So the civic gets a longer rod ratio because of where it's powerband will be located (in the higher rpms).

The 1.8L , with more displacement, makes more torque and has a lower "hauling" or "pulling" powerband. It gets a lower rod ratio.

Please be careful about making statements about the 1.8L LS VTEC peak torque compared to the 1.8L VTEC peak torque. You hear this statement that the 1.8L LS VTEC makes more torque (assuming the same cams , redline, header/ cat/exhaust, and static compression ratio in both engines). In most cases, unlike this myth of more torque in an LSVTEC, the B18C actually makes as much or more peak torque..BUT AT A HIGHER RPM: it's rod ratio is higher or longer than the LS VTEC's. The key here is: the VTEC engine with a better rod ratio can happily rev all day at a higher rpm than the LS VTEC over the years. You can push a stock B18C bottom end to 9000 rpm as long as the valvesprings are upgraded. You can't go to 9000 rpm on a stock LS block's rod ratio.


quote:
--------------------------------------------------------------------------------
Originally posted by Pollux

I know you probably hate repeating yourself Tuan, but thanks for all the help, I think we also covered some good things and those links were great!


--------------------------------------------------------------------------------




Yes. It's a bit tedious saying things again and again but I hope that if I say it in different ways, more people can understand these basics. It's great to see when the light comes on for someone who never knew this before and they get it. It's great to see them then pass that info on to someone else...all in the name of building a better faster car for yourself...which was why we love this hobby: we're speed junkies.

This thread hints at some other concepts like the idea of engine package or engine combination. It hints at parts affecting powerband location.

I milk the idea of package over and over to beginners. A low rod ratio motor likes a certain intake manifold runner length / diameter , intake port shape and size in headporting, cam spec, header length/diameter, exhaust diameter. A short rod ratio motor likes a totally different set of parts with different design characteristics. And with these packages, the powerband (which is about 2000-3000 rpm in width if you are a good tuner) can be moved up or down the rpm range to your liking. Where it is placed dictates your tranny gear ratios. The narrower and peakier the powerband, the more gears you will need. You want your shifts to fall to an rpm just below peak torque to get the most acceleration.

It all ties together. Buying a part without overseeing how it fits in the whole thing makes for a disappointing result both at the dyno and more importantly, at the track...it's a lousy feeling not getting what you expected based on how much you worked hard for, saved, and spent...all because you don't understand engine package, powerband locating, and gearing. Trust me, I've been there. I eventually learned from pretty smart generous people. Hope this helps you guys think it through better and avoid the future letdowns.

As far as costs go, converting an LS to an LS VTEC can vary from $2000 to $10,000: the bare basics with a stock LS block and no change in the bottom end internals will run you $2500 for the head (legitimately obtained and not stolen of course), machine prepping of the head ducts and dowel pin alignment, VTEC ECU & wiring harness, and proper install. Some people, like importbuilders.com for instance, charge as much as $8000 for the whole shabang with a lot more upgrading on the cams,valvetrain/cam gear, and bottom end.

As I said, most people move the CR up and keep the revs at 8000 rpm max. Please look at Chris' dyno above again. In an LS VTEC with an 11:1 CR and ITR cams: over 185 whp and a well-tuned flat torque curve from 6000-7500 rpm sitting at peak torque for that powerband (6000-7500 rpm)...and a nice safe 8000 rpm redline. That's all you need to run low 14's-high 13's et (assuming decent tires, engine mounts, and springs), all day, every day without going kaboom IMHO. If you want more than this by having 11.8-12:1 CR and cams with 12-12.5mm lift, 255-260 duration in an all motor setup, that's your business.

I suggest at least talking to people like drtracing.com or c-speedracing.com for their advice and experience , if you are thinking of doing this. They don't charge $8000-$10,000 for an LS VTEC build up.The oil/coolant leak thing and lower revs than a VTEC block are huge issues to remember for the LS VTEC reliability.



cheers"

as posted by user TUAN on automotivetech.org

http://www.automotivetech.org/forum/showthread.php?s=&threadid=3854

also go here

http://www.theoldone.com/articles/badtothebone/
 


iamgod

Banned
flow charts for B-series VTEC heads



this is a chart of a B18C(5)5 head plotted against a toyota 2ZZ-GE head, the chart is posted for reference of the B18C(5) head, you will need to plot it on the following chart or compare the numbers to see how the C5 head is against other B-series VTEC heads




this is a flow chart of a B16a head VS. a B18C(1)



B16a vs. H22a vs. F20C, you can see how the b16a head fits into the grand scheme of things here
 

iamgod

Banned
some other general information

http://www.hondaswap.com/forums/index.php?showtopic=11

here is a kit made by eagle, it looks quality and i have heard good things about it so far

http://www.robearracing.com/pd_golden_eagle_full_vtec.cfm

here is whats included for the lazy people who don't want to go look

"FULL VTEC CONVERSION SYSTEM

- We now have a Full Vtec Conversion System for people that want to use an LS/VTEC or B20/VTEC set-up.
- This kit is the easiest and most complete way to supply oil to the head without any machining required and is very clean and reliable.

The kit includes:
- 1. Golden Eagle Vtec Conversion Sandwich Plate with a -6AN fitting for the plate and head.
- 2. -6AN steel braided teflon hose for oil supply
- 3. Golden Eagle Vtec Conversion Dowels for proper alignment of the head and block without machining
- 4. 1/8 NPT tap and plug for the oil port in the head
- 5. Golden Eagle worked factory head gasket with any bore size and dowel holes opened for any application

-When we say " NO Machining " we mean that there is no reason that anyone cannot do this kit in their own garage. - The only thing that must be done is tapping the head for the plug .
- The VTEC line and fitting all use existing ports with no need to do anything else.
- Sold as a kit with full instructions.
- Individual parts can be purchased separately."





go here for more of their products

http://www.goldeneaglemfg.com/
 


iamgod

Banned
here is a dyno chart of an LSVTEC using a B16a head plotted against a LSVTEC w/ a B18C(1) head



"Subject: LS/VTEC with GSR head VS B16A head similar mods.



This is a VERY good comparison to look at...

Question: What is the best head to put on my LS/VTEC, GS-R or B16A?

Answer: In the opinion of Atomic and myself, I have to go with a GS-R head.

Look at the graph...here is the 2 motors..

On 1 side we have the LS/VTEC B16A head...coming in at 180 HP...
The bottom end is EXACTLY the same as the GS-R LS/VTEC...exactly...
so it makes for a good comparison.

B16A has:
port flow port/polish (mild)
Civic Type-R intake cam
ITR exhaust cam
Comp valve springs/retainers
Type-R intake manifold

GS-R head has:
Stock head
Stock valvetrain
Stock intake manifold
ITR cams, intake and exhaust.
and it made a little more power, as you can see by chart.
With the GS-R head, you also will definitely get more torque.

For the money though, B16A head is a good choice.
Remember, this is not a perfect test, it just shows a pattern....

Jeff"

go here for more comparison info

http://www.importreview.com/performance.html
 

Goldberg316

New Member
5+ Year Member
10+ Year Member
So i wanna do the crvtec, but i wanna know can you change or put in diff rods or is the block totally based on low revs. But another thing is it that dangereous of a engine to do. Lets say i don't one of the best machine shops in my city is it still a bad idea?? Or would just using a b18 a better rooot to go?
 

iamgod

Banned
Originally posted by Goldberg316
So i wanna do the crvtec, but i wanna know can you change or put in diff rods or is the block totally based on low revs. But another thing is it that dangereous of a engine to do. Lets say i don't one of the best machine shops in my city is it still a bad idea?? Or would just using a b18 a better rooot to go?

i dont understand your first question, this thread does not say that doing one is a bad idea, this thread is about teaching you the RIGHT way to do it
 

h22a4civic

New Member
Registered VIP
5+ Year Member
10+ Year Member
Originally posted by Goldberg316
So i wanna do the crvtec, but i wanna know can you change or put in diff rods or is the block totally based on low revs. But another thing is it that dangereous of a engine to do. Lets say i don't one of the best machine shops in my city is it still a bad idea?? Or would just using a b18 a better rooot to go?
ok , im like IAMGOD, i have no clue what ur sayin, i have been running ls/v for the past year, and im going to say fk the gsr on this one cause ill out do them, the sites and posts he make were off the hook, I disagree with none of them, but i do say if your a newbee to the import secene, i say a stick with the b16, ls/20/vtec are pretty complicated, and realy you can get a machine shop to do it, but if your like me, you want to do it your self, so that way you know things are right and precise, plain and simple if your new stay with b16 you will not be let down!!!!!!!!
 

Goldberg316

New Member
5+ Year Member
10+ Year Member
Since the b20 can only rev to 8000 safely, can you put in new or different rods to make the lenghth of the rod better for a high rev. Hopefully thats a little better:???:
 

KennyC

New Member
Registered VIP
5+ Year Member
10+ Year Member
so in ur opinion do u think a ls/vtec is a good thing or it jus better to swap a factory engine ?
 

KennyC

New Member
Registered VIP
5+ Year Member
10+ Year Member
and im buyin a ls teg so if i bought the conversion kit (which i would rather do then have it taken to a shop) can u show me where u were reading about people experiences with the kit ?
 

KennyC

New Member
Registered VIP
5+ Year Member
10+ Year Member
also is there any sites that show a ls/vtec build guide using the ls/vtec kit ?
 

h22a4civic

New Member
Registered VIP
5+ Year Member
10+ Year Member
Originally posted by Goldberg316
Since the b20 can only rev to 8000 safely, can you put in new or different rods to make the lenghth of the rod better for a high rev. Hopefully thats a little better:???:
HELL NO, i say it can safely rev to 6500, you can put in forged rods, but that wont help the cyl walls, if you want to run to 8k u have to get it resleved!!!!!!
 


Top