SpeedMonkeyRacing

Here's something I would like ot know.

If VTEC doesn't do well w/ Turbo..why does VTEC engines can produce more HP than non-vtec engines? I've never seen any built LS engine to hit over 500whp yet there are plenty of GSR engines to hit 500whp or more. Why is that?

Jeff-

RGAZ

The VTEC is not good for turbo due to increased valve overlap during the VTEC cam timing.

The GSR engine can do more than the LS due to head/comb chamber differences and a higher base-compression ratio.

VTEC can be good for turbo if a non-stock cam is used and it is designed for turbo use.

Randy

97integraLST

is it true that sometimes people disable Vtec? correct me if I am wrong.

Thanks.

turbopanda

The same sort of rumours spread around here where I live too, which is a reason why there's only a handful of turbocharged honda's running around. I think its a myth though. Turbocharged hondas break down more easily than a normally aspirated Honda, yes that is true, but not always - if the driver drives a turbocharged honda with respect and takes good care of it, it should be just as reliable as a normally aspirated honda. There are so many kids out there who don't know how to drive them properly, don't run with the right electronics, don't know warning signs of when things are about to go wrong, and so they break down and blame the turbo and not themselves. My car has been turbocharged for over 2 years now, and although i've had my hand of problems, everything has been sorted out and it runs strong now. I'm happy because I'm still able to kill all those damn CRVTECs running around on the streets too - they all think they're so fast just because they're running a 2000cc engine with a DOHC VTEC head. Bah.

rtype11

by disable they mean always engaged on the highest lift cam, or better said the cam profile that provides the highest flow.

you can produce more power on an ls if you want, things that prevent this actually being done are as follows: LS lacks oil squirters taht is why I made a LS/GSR block, using the LS crank and pistons and rods in a GSR block - this gives me extra piston cooling which increases my detonation threshold, a properly built LS head flows just as well as B16 or 18C5, it makes more sense to bore out or stroke a GSR or R block because of the squirters and because of the girdle holding mains 2,3 and 4 together.

B18B is a very good base and has excellent torque numbers on a low reving engine, the tranny that comes with the LS is also better designed ratio wise for dragging, but lacks a dif. mathematically I have built an LS that can make 650hp and 430tq redlining at 9200 on fuel, but it is comprimized because of the cooling and bottom end strength of the mains, therefore I would rather have a GSR to play with.
LS are also disposable motors.

Full-Race Geoff

An LS has poorly designed ports, in conjunction with very small valves. VTEC does make more power for a number of reasons. Some people have been able to make huge power using so called all motor cams and dialing out the overlap with the cam gears

I also know one person who swears by b16 cams. IMO gsr cam is ideal.

Big James

The reason people think that VTEC is not good with turbo is because, like mentioned above, valve overlap. However, with cams, or cam gears, most of that can be dialed out. The other thing that people have problems with is tuning. It seems a lot of tuners have problems when it changes cam profiles with getting a good A/F ratio. Find a good tuner, or get a good standalone, and that is tken care of also.

SEFIxCivic

in addition the rocker arms on the LS head are very flimsy compared to the DOHC vtec heads. I've seen rocker arms flap right off due to its inability to survive high rpms.

DLB1994

i seen h23 non-vtec put out 560whp thats has no vtec and over 500hp

bigTom

dont forget... thats 2.3l as well... iv seen gsr motors put out 650+... the ls blocks are also differant if u just look at them... the cast is completely differant for the block, next time u have 2 side by side... look at them ... as for cam overlap... look what the pro's are running... and they are running tha fastest... (with vtec motors!)if the ls was a better motor (and stuff is cheaper then) why wouldnt they use it? any decent tuner will be able to overcome the cam overlap... there are a lot of bullsh!t rumors out there about what works and what doesnt... and sadly enough... people believe the bs rumors... for one... the ls tranny is better for boost... unless ur only going for top speed... the ls tranny stinks... as for oil squirters... i know some people actually take them out for more oil pressure

oh... another big misconception which seems to float around this board that i have recently become aware of (reason being cuz i thought it was a good idea) is the oil feed off the vtec selonoid for the turbo... u dont really get much oil pressure there till vtec engages... and some people turbo's are already spooling up before that (actually most peoples turbo's are...) one person i know blew up several turbo's having that as their oil feed and then they realized that was the problem

bigTom

this is what io was talking about
http://www.imagestation.com/picture/...a.jpg.orig.jpg

rtype11

I just dont like the comment that the LS stinks, it has its applications, my car makes all kind of JAM, gobs of torque at low rpms, how does that compare to a whiny typeR that has been built to 11000RPM and still has no torque. Not a fair statement, every tranny has its exact application, to flat out say it is bad is I feel unfair - let the flaming begin!

boosted3g

I really think it has everything to do with the cams. I have tested nearly every cam Crower makes and the bigger ones always make more power even on the turbo cars. I plan on running the 404's because they are great with turbo. Crower for some reason or another Crower markets a cams that they call a turbo cam that barly puts out more than the stock one. So in my opinion the secret lies in the head. The main cap thing is no big deal its available in the aftermarket and they are easily obtainable. As for the oil squirters we weld them shut and feel they are overrated on a race car. So my final answer is the cylinder head is the reason.

bigTom

didnt mean to offend u... what i meant was not that the tranny itself stinks... more-so that its not good for drag racing... a shorter geared gearbox will simply make u go faster... hence why my comment... (i drag race)

Type-ARR

ummm, I dont have a torque problem in my type-R, to say that an LS makes gobs of torque is going a bit over board I think......

xxplosif1

the LS has more LOW end torque than any vtec engine, thats why he said that. So yes, it will "feel" more powerfull than any b16a or b18c. Even if the type R makes 128 of torque, it still feels like a B16a imo. Of course, the vtec is much more agressive then the B16a.

Project_Integra

I was doing a little research, and there's only one obvious reason for the LS to have more torque than the B16/B18c. The displacement of the B16 is 1595cc while the displacement of the B18c is 1797.36cc. The displacement of the B18A/B is 1834.77cc. That would explain the lower end torque that the LS has over the other engines. However, I'm not sure where the extra displacement comes from, but I assume it comes from the block, because of the increased power that people get from LSVTEC setups.

I still don't know whether to keep my LS then Turbo or swap a B16 in there and then boost it......

gsr camel

nissan put variable valve timing on their silvia and it has 50 more hp than the normal camed version!

One thing tho the nissian valve system was made for the turbo not for peak N/A hp!

Ri5e

The extra displacement is from the LS's longer stroke.

DIRep972

iTrader: (1)

dont u dare, u will never be my friend of u do this

DIRep972

iTrader: (1)

Heres my whole take on the whole vtec being bad for turbo thing.. vtec is not bad for turbo at all, its just that what makes a good NA motor is different then what makes a good turbo motor.. I wish I knew more about this so I could explain what im thinking..

an LS motor and a GSR motor make the same torque, but the GSR motor will make more hp.. They have there torque curves in different places and the GSR motor is alot more peaky.. this is why u do NOT want an LS tranny on a GSR, you will fall below the motors torque curve..

people talk about cam overlap this and that but that is all BS, you will make more power by flowing more boost, as long as u arent haveing overlap.. The stroke of the LS is better suited for bottem end power but it does great with a turbo, thats why LS alot of the time put out MORE torque then a GSR on same boost, but if u look at the hp, teh GSR will have about 40hp over the LS..

yeh so random tangent ill end my post now since im goning no where with it..
vtec + boost = top end hp
top end hp=good
therfore vtec + boost= good

Lei Siew Long

first off, i've seen a few ls motors make 500+ hp.

secondly, with the rumors being that the ls tranny doesn't live up to the hype, does that mean i should get a gsr tranny for my ls engine with boost?

has anyone actually tested this theory about the gsr tranny being better than the ls tranny for boost and vice versa? it would take a lot of consistency on the track but, it can be done.

PROFILES2000

thanks tom ive seen pix of that before and i was actually wondering what and why

bigTom

yea... i liked the idea at first but then i heard doubts... now i finnally found out y... i like hows it setup... but the whole concept is wrong... if u look at the head... where the v-teck selenoid is... that oil passage is right there... oil pressure goes there when vtec is engaged... which isnt something i would exactly trust as an oil feed

Project_Integra

So if Vtec is good and boost is good, why should i get my B18a?? How is your setup coming along? What should I expect....I wanna know things like that. IM me on AIM my screename is IconGrafixInc.