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."
"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."