specie

My winter break is coming up soon so I'll have some time on my hand to rebuild my motor.

I have a stock '92 LS longblock I just bought. Not really sure of the condition but I'm rebuilding for a little boost.

Goals: Support 300hp safely.

Parts: Wiseco 81.5mm pistons, ACL bearings, stock everything else.

???: I haven't decided on a turbo yet. I wanted the T3/60-1 but it doesn't look like I can retain A/C with that. (I live in FL and for the last 2 yrs. I've been driving my CRX w/o A/C and it's getting a little old).

I thinking about a Garret T3/T4 (.57 trim and .60 A/R).

I've talked to a couple turbo-ls owners and the highest I've heard of them reving to is 7,600rpm. I know the stock valve train is good to about 7k rpm (I'm not sure if it'll be okay to go higher). Does the power drop off after 7kpm with the stock ls head/cams? Does anyone here have any experiences with this?

Do I need ARP rod bolts? I'm not reving that high (about 7k). Are ARP head studs necessary? Would I be able to use the ARP head studs from a b16a (on my ls/vtec)?


Thanks.

specie

How high are you LS guys reving to?

lsturbo

7k

DIRep972

iTrader: (1)

torque starts to drop at 6k. horsepower drops at 6700.(check dyno in sig) I rev mine to 7300-7500. stock vavletrain stock block. i guess its safe, nothing has broken yet.


[Modified by DIRep972, 11:47 AM 12/17/2002]

specie

[QUOTE]torque starts to drop at 6k. horsepower drops at 6700.(check dyno in sig) I rev mine to 7300-7500. stock vavletrain stock block. i guess its safe, nothing has broken yet.


So I guess there is no need to upgrade valvetrain. I thought the turbo would help the top-end going, but I guess not.

Thanks for showing me the graph.

DIRep972

iTrader: (1)

well it does help the top end, but it can only do so much. the cams still suck.

JeremyL

LS cams and valvetrain does not suck, im sure it flows a lot better than most of the other 4cyls on this earth

why do so many people on here feel that an engine's worth is measured by how far past 7K you can make it rev, im sure that for far less than the cost of just a B18C swap you can easily 220+ very useable reliable whp out of an LS

DIRep972

iTrader: (1)

if i could rev to 8k, make and maintain my same peak torque to 8k, I would be making 361whp. now tell me again why LS cams are so good?

JeremyL

if that is a theoretical or estimated number it is probably about as useful as the dyno charts on the jackson racing website

RicerRacing69

hah, i think what he means is that if the slope of the HP gain was to stay the same to 8k rpms the HP would be at 361WHP

specie

LS does not suck too badly with BOOST.

I'm kind of uncomfortable with high revs (but it is fun in my ls/vtec though) and the possibility of a misshift.

Thank you guys for the answers. I'm just going to stick with stock valvetrain and cams.

specie

Yeah, I know what you're saying. Even when I had a car with A/C, I didn't use it but once or twice. It just feels unnatural to drive with the window up. However, my gf isn't too happy about NO A/C. When a woman is unhappy, life is like hell....

DIRep972

iTrader: (1)

no. I got that # from taking my current peak torque(237ft/lbs), and calculating it by rpm/5250 to get hp. (as if the torque stayed flat to redline like on a vtec motor)

but....my car will never make 237ft/lbs @ 8k RPM's because 1)stock vavletrain cant rev that high and 2)stock LS cams wont make torque that high.

Im not dissing on LS motors, dont take it personal. I have an LS motor too and its making good power. but not near as much as it could be.

specie was dissapointed the turbo didnt help out w/ power after 7k rpm's. it does actually, compare my torque curve with that of a stock LS, torque is maintained longer but the turbo can only as much as the cams and head will let it. why do u think vtec motors make so much more horsepower w/ the same peak torque then LS'?


[Modified by DIRep972, 6:37 PM 12/17/2002]

JeremyL

but isnt it not only safer but more streetable to make the same power at lower rpm, i mean if one motor has 300hp at 6k and another has 300hp at 8K and both motors are in the same car i would bet on the 6K motor to make the car faster

Speed PHreak

High lift/low duration cams own for LS engines, hands down. You can keep the stock idle quality, and they pull like a banshee all the way to at least 8k. I've got a set in my LS, with a crower valve train, and a mild P&P job. It tears all the way to 8k, I don't have the ***** to take it any higher than than. The cams i've got are a custom set close to Crowers 62402T, but with a more duration. All I can say is........VTEC WHAT?

DIRep972

iTrader: (1)

u could make that assumption. but on a small displacement motor like in a honda, its gonna take ALOT more boost to make 300hp @ 6k rpm's then at 8k. so u could also make the argument that the higher revving motor on less boost will be safer. but these are just assumptions, I was just trying to point out that the cams are the main reason for the LS's drop in power at 6700rpms.

JeremyL

hmmm maybe thats why the stock redline is at 6200rpm lol seriously tho vtec has its + and - and so does non vtec, theyre both good and whichever i had i would exploit their +'s and try to minimize their -'s

for my project i may even get rid of my T3 and get a smaller T3 or maybe even a T28 which would mean a different manifold and that would mean more money so unless someone wants a drag style T3 mani for $300 i probably wont be doing that. The smaller turbo will help to maximize the LS +'s which is a more streetable power curve with the quicker spooling turbo and isnt too small to still make power at 6800rpm with some decent cams and upgraded valvetrain

InTeGrA B18b1

u really get 30 mpg?

DIRep972

iTrader: (1)

yes. on my last road trip I actually got 33mpg. 550cc injectors. it is made possible thanks to hondata and vaportrail.

Speed PHreak

Same here, I still get 25mpg around town and 30-ish on the highways.

Jdm_Rice_Monster

I have my shift light set at 6600 and I always hit myrev limiter on my crx, I am running the pr4 I have ls turbo. I feel like the ecu is cutting my power short. I dont want to buy some ecu with like a 9500 redline Like I always see for sale because I am afraid of a mis shift, I dont think my stock ls would like the 8k plus range at all. Is there some cheap way other than a mangement system to raise my limit a bit, and is there any other guys with this problem.

specie

You can just buy one of those chips and not rev that high. Shift at about 7k rpm. You can get a Zdyne standalone and change your rpm. Regardless, when you mis-shift the rev limiter isn't going to help. It only cut off your fuel when you're still in that gear under load.

JeremyL

any B series motor if driven reasonably should get around 30-33mpg, the reason why Honda's from the factory dont get this (usually) is because they tend to run quite rich at WOT conditions, they obviously have reasons for this but if you can lean out the curve (with an AFC or a standalone) up top and maintain a safe AF mix you can really improve fuel economy

if i am wrong someone feel free to correct me or add your own $.02