good ls/vtec info

#1
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 http://www.drtracing.com who has done several of these reliably.

question
....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
/question

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.

<3 tuan & temp.

#2
Good job roberto :) is it alright i call you that?
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#3
:up: for this info im building an ls/vtec in the ek. still not sure if i wanna run a longblock and do everything from scratch or just use the LS thats in my egg and swap the head. the longblock would be a long buildup. but after its all said and done it would be worth it. just dont know if i have the patience. thanks for the links man. very very good info.
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