spaghizzle

Ok, please dont flame me, im completely new to this. I currently drive a 1.8t jetta which i love. Im looking to get a 95 civic hatch as a project car. Forced induction is a must for me. I love the feeling of a turbo being fully spooled.

OK, so on to my question. I was told (and i guess this makes sense to me) that the LS engine is better for forced induction than the GSR engines. Now obviously a turbo is a effective because it forces more oxygen into the same amount of space. But when VTEC kicks in, the more radical cams flow more air, faster, through the engine. And this kinda works against the turbo trying to compress more air into the chamber.

Does this make sense to anyone? Basically i was told VTEC works against forced induction. Is this true?

ricodemus

I think you should look at some dyno posts and tell me if you still think vtec works against FI. I think most agree that the shortcomings of a turbo'd honda is that proper tuning is necessary to be reliable. The sleeves in a stock honda block can't resist detonation as well as a cast iron block. Also, a gsr will always make more power than an ls if everything else is the same, but the ls is more favorable because it has lower compression, so its safer to just throw on a setup and go. LS's have made great power though also, I'm not trying to demean them.

psi420

I would say your somewhat correct, however you can tune the cams to eliminate some of that extra overlap.

My Turbo GSR at 8psi spanks on my friends Turbo LS with 9psi

spaghizzle

is it possbile to put on a thicker head gasket to lower compression?

Im not sure which block is better for boost, the LS or GSR? or are the block the same, and the head is the only difference?

Keep in mind, im coming from an engine that built for boost, so i see 21 psi every time i step on the gas.

twkdCD595

as he says, you can tune out the overlap of the more aggressive vtec lobes and you will no longer have that problem.

yes it is possible to lower compression with a head gasket... the only downfall being the gasket can blow out under high boost (not seen it but some say it happens).

sweet

iTrader: (5)

first off there is nothing wrong with the LS (B18B) motor, it's great for turbo and other appl. BUT the GSR (B18C1) motor is even better for turbo. the reason alot of people say that the LS is better for turbo is due to the lower C/R which resists detonation more than the GSR, and the fact that only one cam profile needs to be tuned. on the GSR there is almost a full C/R point more and 2 cam profiles to tune, and most peole don't want to do extensive tuning so they end up ruining the GSR motor much quicker than the LS. so that's how they come to the conclusion that the LS is a better turbo motor.

IMO go with the GSR motor cause it'll make much more power over the LS, though it'll be at a higher rpm due to the design of the motor. but if you're on a budget then get the LS motor and turbo that since it'll be much easier to tune and costs less.

BTW this topic has been debated or talked about for a long time. bottom line is the GSR is better cause it makes more power with the same amount of boost than the LS.

Lsos

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">But when VTEC kicks in, the more radical cams flow more air, faster, through the engine. And this kinda works against the turbo trying to compress more air into the chamber.</TD></TR></TABLE>

Well, flowing more air faster is the whole point. The higher lifting, longer duration cams means that the turbo doesn't have to work as hard to push air into the chamber. If the cams were very mild such that the valves didn't open as much, or not at all, then less/no air would get into the chamber. The turbo would create a lot of pressure in the intake manifold, but that would do you no good until the valves open to let the air in where it belongs. The more they open, the more air gets in.

VTEC can be potentially bad because of overlap, which allows the possibility of exhaust gases getting sucked back into the cylinder. The more exhaust backpressure you have, the bigger the problem, although I really don't know how this affects Hondas. I imagine you could get rid of this by simply tuning the exhaust valves to close earlier, if it's really a problem...

spaghizzle

wow thank you all for your help. I probably would have got slammed for asking such a newb question on VWVortex. maybe someone can post a link to some of the lenghtier debates about FI on a LS engine Vs. a GSR engine.

sweet

iTrader: (5)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by spaghizzle &raquo;</TD></TR><TR><TD CLASS="quote">is it possbile to put on a thicker head gasket to lower compression?

Im not sure which block is better for boost, the LS or GSR? or are the block the same, and the head is the only difference?

Keep in mind, im coming from an engine that built for boost, so i see 21 psi every time i step on the gas. </TD></TR></TABLE>

there is no reason to lower the C/R on the GSR, 10:1 is fine for turbo. ITR motor's with 10.6:1 C/R are successfully turbocharged. some even go higher on the C/R depending on what the car will be used for.

keep the C/R at a moderate level and then match a turbo that will make power in the desired boost range. a stock GSR motor with 10-12 psi will be pretty nice if it's tuned correctly. some even run higher boost levels, like 14 psi, on their stock motors without a blockguard or anything.

the sleeves of the B18B and B18C1 are the same, both open deck and can't handle lots of boost before moving/flexing. the crank stroke and rod length are different between the 2 motors (LS has 37cc more displacement), as are the head, cams, IM.

you mentioned you run 21 psi on your current motor, i'm assuming you're talking about your newer 1.8T? what is the stock psi level from the factory?
also what kind of turbo are you using, the stock factory one?

i do agree that the 1.8T block is built much stronger from the factory than the Honda 1.8L's. but Honda doesn't turbo their motors so that is one reason why the sleeves are open deck. also not all turbo's flow the same (obviously) so your stock turbo running 21 psi may not be making too much power really. if you change to a different, larger style turbo you can run maybe half the boost level and make the same amount of power. that's just an example, cause there are lots of variables involved depending on what turbo you use etc.

E-Rok

stock vs. stock a GSR will always make more power per PSI because of the higher compression and the better flowing head. fully built vs. fully built with the same head id say the #'s would be similar. but back to the topic, VTECis great for turbo cars, but you just cant have too much overlap, thats whats bad for turbo cars.

Mr. Softee

only reason i prefer the ls motor is because it is cheaper yet still potent. with the saved cash, you can upgrade the internals and boost higher

soundman

The B18C1 motor has a girdle at the bottom of the crank, and helps the bottom end be more sturdy. The LS does have more displacement however. Another advantage of the B18C1 block is that it has oil squirters below the piston to squirt oil up onto the piston, while the LS does not.

Either setup can be turbo charged, but you have to look at whether you will be runing this as an everyday driver, or as a weekend racer. If it's everyday, then I say go with the LS, but if it's weekend go with the GSR.

You will have to watch overlap as the others were saying, because as the VTEC in the NA motor begins, it begins letting overlap to allow the backpressure in the exhaust to pull the intake air into the cylinder. In a turbo, overlap can take all your pressure away by just sucking the air right from the intake to the exhaust during overlap. That's why some say it's better to use LS because you wont have as much overlap with the LS head as you do with the VTEC head.

I would like to take and make an LS head stronger, so you could raise your REV limit to 9000 or so, and then match it with a VTEC GSR and see what happedns. It would be interesting to see what that plus a good port and polish would do with the LS engine.

sweet

iTrader: (5)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by soundman &raquo;</TD></TR><TR><TD CLASS="quote">The B18C1 motor has a girdle at the bottom of the crank, and helps the bottom end be more sturdy. The LS does have more displacement however. Another advantage of the B18C1 block is that it has oil squirters below the piston to squirt oil up onto the piston, while the LS does not.

I would like to take and make an LS head stronger, so you could raise your REV limit to 9000 or so, and then match it with a VTEC GSR and see what happedns. It would be interesting to see what that plus a good port and polish would do with the LS engine.</TD></TR></TABLE>


yeah, i forgot to mention the squirters and girdle on the GSR.

also i was thinking about reworking an LS head for turbo to see what kind of possible performance could be had, and then using the B18B for turbo instead of the B18C. since the costs are normally much cheaper for the B18B itself and the parts for it. in most cases i've seen the B18B makes less HP than the B18C but makes more TQ, so it's definantly not a bad idea to use the B18B for turbo.

soundman

I think an LS head with a port and polish, and stronger valves, and springs could go higher into the REV limit, and with the turbo be very effective. The overlap on VTEC will kill ya.

94dxt

gsr is a "performance" motor

Mr. Softee

i just picked up a heavily portd ls head. ill let you know how high it makes power sometime late summer or fall.

soundman

What REV limit are you planning on runing?

TurbothisLS

bottom line is the GSR is better cause it makes more power with the same amount of boost than the LS.

but i can run more boost than a GSR because of less tuning hazards and lower C/R
GSR is a good motor, but LS is easier to replace and run higher boost from factory

mamaboy

If your doing a project....why don't you just build the engine from scratch...used Type R/CTR/GSR head with a Dart Block....gotta love that fact that it's closed deck.....and throw in some pistons, rods, crank, and just do it right the first time out......and pick up a GSR tranny and voila! Take it slow and do your research....Cracked sleeves and rings are common in FI hondas even with somewhat of a complete tune.....it's just not an FI vehicle....remember these are all NA cars...so the block is where i'd focus everything....and gettiing your hands on a high flowing Type R head wouldn't hurt either...and the GSR tranny for its favorable gear ratios.....and voila your done.....
Then the turbo comes into question....T3/T04e ..... 60-1......kit or non kit....custom or pre fab.....aem, hondata, power fc, safc, emanage, or the fmu +inline...blah blah blah...blah blah blah....pardon me fellas i just had my car jacked and just sold most of my turbo parts...just felt nostalgic.....

-iLLuZioN-B18C1

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by spaghizzle &raquo;</TD></TR><TR><TD CLASS="quote">is it possbile to put on a thicker head gasket to lower compression?

Im not sure which block is better for boost, the LS or GSR? or are the block the same, and the head is the only difference?

Keep in mind, im coming from an engine that built for boost, so i see 21 psi every time i step on the gas. </TD></TR></TABLE>

it is possible to put on a thicker headga. to lower compression, but it is a 'bandage' job of lowering CR. the real way is pistons.

as for which block is better for boost, the GSR is better hands down. pound for pound, the GSR will make more power than the LS. GSR head flows alot better as well. the only reason people turbo ls is b/c it is a much cheaper route or they already have a ls engine to begin with. if money is not that big of an issue, then do the gsr. if money is an issue, go for ls.

it also really depends on your HP goals. you say you see 21 psi all day. how much hp are you use to? the psi of boost doesnt help, be more specific. 21 psi can mean 300whp or 500 whp for all i know.

if you want raw power, then build up a GSR block to handle 21 psi.
if you think about 400ish is good enough, i would build a ls block (blocks are much cheaper) throw in some forged rods, pistons and sleeve it. then itll be able to handle 21 psi. but then at that point (with hondas/acuras at least), your gonna need to upgrade tranny to be able to handle the power and axles so you dont break them when you launch hard.

spaghizzle

well for me 21 psi is good for almost 200 hp and 240 ft lbs, at the crank. I have never tracked my car, but people on vwvortex with simlar mods are running consistent low to mid 14's with full interior.

I Like Boost

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by spaghizzle &raquo;</TD></TR><TR><TD CLASS="quote">well for me 21 psi is good for almost 200 hp and 240 ft lbs, at the crank. I have never tracked my car, but people on vwvortex with simlar mods are running consistent low to mid 14's with full interior. </TD></TR></TABLE>

If I was running 21psi and only had 200 at the flywheel i would shot myself. get a honda soon. btw mike aka motormatrix.com made like 550 at the wheels on 22psi but his turbo is like 4 of the little k03 so i guess its not a fair comparison. oh and go b18c VTEC, 8k rpm with a fully spooled turbo sounds INSANE.

-iLLuZioN-B18C1

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by spaghizzle &raquo;</TD></TR><TR><TD CLASS="quote">well for me 21 psi is good for almost 200 hp and 240 ft lbs, at the crank. I have never tracked my car, but people on vwvortex with simlar mods are running consistent low to mid 14's with full interior. </TD></TR></TABLE>

dude if your only used to 200 hp then ls or gsr will do that just fine STOCK. depending on the tuning, the gsr can push around 270 whp wit stock block.

welcome to Hondas

Pengo

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jvithayapun &raquo;</TD></TR><TR><TD CLASS="quote">

dude if your only used to 200 hp then ls or gsr will do that just fine STOCK. depending on the tuning, the gsr can push around 270 whp wit stock block.

welcome to Hondas</TD></TR></TABLE>

yea if ur lookin to push 14s with around 200 hp, then even a boosted sohc in a hatch at 6-8 psi on a small greddy kit will do

SiRkid

vtec+turbo= good
wherever you heard it wasnt..dont go back there or listen to who told you that.