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[silverac]

 what up fellas. look i wanted some 9.1, 81.5 mm pistons so i asked for a set of these in wiesco and i get them. when i look up the parts number (km41m815) i realize that wiesco dosent make a 9.1, 81.5 for a ls. what they make is a 8.3-8.6, 81.5 mm. depends on the decking height but if its stock like mines that puts me at 8.3. now correct me if im wrong but this is real low right. im trying to hit 450 on pump gas with a fully built ls (stock sleeves) t3 60-1. built head. is this still doable or not.

[jdmhatchracer94]

possible i will let you know. Me and ratcityrex have the same pistons. 450hp fuck that I'm goin for 600 on a stock ported head. dout it will happen though. You should be able to do it

[silverac]

damn 600 is a beast. thats the thing tho. a car with the exact same setup and lets say stock compression 9.2.1 will make more horsepower,. ur still in the works on your project right, id like to see what kind of numbers u put down

[chris]

The vitara builds are making 400+ with mid to low 7 compression

[silverac]

The vitara builds are making 400+ with mid to low 7 compression

damn thats low

[Annihilator]

low compression = safer for higher boost numbers.

For reference, first gen DSM's run right around 7.8:1 compression from the factory, and they take some pretty nasty boost levels out of the box.

Higher compression will obviously make better power on the same boost levels, but the higher compression you go, the higher the cylinder pressure.  Detonation on higher cylinder pressure is a lot more dangerous.

I didn't plan on this post being this long.  Basically, it's all up to what you want.  Some people boost 10:1 compression because they want decent power out of boost, and some boost lower compression because they want some nasty boost levels.

 - Steven

[silverac]

well my plan was 9.1 which is pretty much stock but they sent 8.3

[Annihilator]

honestly you won't notice a huge difference between 9.0 and 8.3:1.  I mean, you might notice a little difference, but it's not going to be so noticeable that you'll just want to rebuild the motor for that extra .7:1 CR.  It just means you can turn up the boost some more 

[jdmhatchracer94]

my buddy had a ls with ross piston put him at around 8.5 comp couldn't notice it really still smash on a few si's when he was n/a

[silverac]

my buddy had a ls with ross piston put him at around 8.5 comp couldn't notice it really still smash on a few si's when he was n/a

well ill find out. ill be at 8.3, n/a might suck, only till i break the motor in

[TTC]

If its any consolation I run 8:5:1 on a toyota motor and off boost isnt bad at all.

[Joseph Davis]

what up fellas. look i wanted some 9.1, 81.5 mm pistons so i asked for a set of these in wiesco and i get them. when i look up the parts number (km41m815) i realize that wiesco dosent make a 9.1, 81.5 for a ls. what they make is a 8.3-8.6, 81.5 mm. depends on the decking height but if its stock like mines that puts me at 8.3. now correct me if im wrong but this is real low right. im trying to hit 450 on pump gas with a fully built ls (stock sleeves) t3 60-1. built head. is this still doable or not.

Even with cams and 33mm intake valves, Edelbrock Vickie-X IM, and a topmount turbo manifold 450 whp on pump gas ain't going to happen.  Or, it will like the B-VTEC builds and then come apart in a few thousand miles because you are straddling knock limit.  Just like the B-VTEC builds do.

Trying to max out knock limit is fucking retarded, dude, engines last 50 times longer if you exceed your octane requirement by a significant margin.  Octane is coolant for your combustion chamber, what you are trying to do is the literal equivalent of:

what up fellas. look i wanted some 9.1, 81.5 mm pistons so i asked for a set of these in wiesco and i get them. when i look up the parts number (km41m815) i realize that wiesco dosent make a 9.1, 81.5 for a ls. what they make is a 8.3-8.6, 81.5 mm. depends on the decking height but if its stock like mines that puts me at 8.3. now correct me if im wrong but this is real low right. im trying to hit 450 with my radiator half full with a fully built ls (stock sleeves) t3 60-1. built head. is this still doable or not.

[silverac]

what up fellas. look i wanted some 9.1, 81.5 mm pistons so i asked for a set of these in wiesco and i get them. when i look up the parts number (km41m815) i realize that wiesco dosent make a 9.1, 81.5 for a ls. what they make is a 8.3-8.6, 81.5 mm. depends on the decking height but if its stock like mines that puts me at 8.3. now correct me if im wrong but this is real low right. im trying to hit 450 on pump gas with a fully built ls (stock sleeves) t3 60-1. built head. is this still doable or not.

Even with cams and 33mm intake valves, Edelbrock Vickie-X IM, and a topmount turbo manifold 450 whp on pump gas ain't going to happen.  Or, it will like the B-VTEC builds and then come apart in a few thousand miles because you are straddling knock limit.  Just like the B-VTEC builds do.
ok mr. jd. i already know you tune cars and shit so what do u think is a more realistic number.

Trying to max out knock limit is fucking retarded, dude, engines last 50 times longer if you exceed your octane requirement by a significant margin.  Octane is coolant for your combustion chamber, what you are trying to do is the literal equivalent of:

what up fellas. look i wanted some 9.1, 81.5 mm pistons so i asked for a set of these in wiesco and i get them. when i look up the parts number (km41m815) i realize that wiesco dosent make a 9.1, 81.5 for a ls. what they make is a 8.3-8.6, 81.5 mm. depends on the decking height but if its stock like mines that puts me at 8.3. now correct me if im wrong but this is real low right. im trying to hit 450 with my radiator half full with a fully built ls (stock sleeves) t3 60-1. built head. is this still doable or not.

[Joseph Davis]

You won't lay down more than 350 whp on street tires.  With cams, an LS can do that power figure.

E85, 110+ racegas, etc, take that 60-1 to the max.

[silverac]

You won't lay down more than 350 whp on street tires.  With cams, an LS can do that power figure.

E85, 110+ racegas, etc, take that 60-1 to the max.

damn that suks. i was hopeing u would say atleast 400. 350 on a built ls and i know dudes doing close to that on stock ls with smaller turbos

[Joseph Davis]

Dynojet numbers, maybe.

[silverac]

Dynojet numbers, maybe.

well the shop we go to has an all wheel drive dyno. u can put load on it and all that shit i know nothing about. whats the most have u gotten out an ls

[Joseph Davis]

290 whp.

No one brings me LS, I am too lazy to assemble mine (shooting for 700 whp).

[silverac]

290 whp.

No one brings me LS, I am too lazy to assemble mine (shooting for 700 whp).

well i may bring you one lol. not sure hoe far nashville is from va but im quite sure its closer than me going to ny. i know we can break that 290 record cause my buddy did with a stock from head to toe ls and my setup is pretty solid i think.

[88dx]

theirs no point in building a LS bottom end if your only going to make 350whp

[Joseph Davis]

290 whp.

No one brings me LS, I am too lazy to assemble mine (shooting for 700 whp).

well i may bring you one lol. not sure hoe far nashville is from va but im quite sure its closer than me going to ny. i know we can break that 290 record cause my buddy did with a stock from head to toe ls and my setup is pretty solid i think.

ASHEVILLE, not Nashville.

[silverac]

theirs no point in building a LS bottom end if your only going to make 350whp

u right about that but we talking about pump gas. if i go with 110 i know we can make alot more. ive seen on the internet cats making 500 with a built ls and race gas. now given not everyone setup is the same and a bigger turbo goes a ways but it also has alot to do with the tune. built setup and shitty tune = no whp

[silverac]

290 whp.

No one brings me LS, I am too lazy to assemble mine (shooting for 700 whp).

well i may bring you one lol. not sure hoe far nashville is from va but im quite sure its closer than me going to ny. i know we can break that 290 record cause my buddy did with a stock from head to toe ls and my setup is pretty solid i think.

ASHEVILLE, not Nashville.

my bad that N snuk in

[Annihilator]

theirs no point in building a LS bottom end if your only going to make 350whp

I tend to disagree.  That's just my opinion though.  I don't like running an engine on the edge of blowing up for long periods of time like a road course requires.  That's just for my application though.  Most people won't be at full power for that long.

[silverac]

i agree when it comes to longevity but to build a motor and dump all this cash just to walk away with 350 whp  when i know dudes making close to that on pump with completely stock motors almost makes u feel like it was a waste of money. im in knee deep now so im like fuck it.. maybe i should have went vtec but then ill be like everyone else around my area so my goal was to try and make a non vtec beast so i Can put a fuk vtec sticker on the window. well see what happens.

[Joseph Davis]

i agree when it comes to longevity but to build a motor and dump all this cash just to walk away with 350 whp  when i know dudes making close to that on pump with completely stock motors almost makes u feel like it was a waste of money.

Then dump race gas in it and turn the boost up. 

I don't see what the problem is?  It's a limitation of the fuel, not the engine.

[ratcityrex]

Like JD said, People are dumb as fuck. Pushing a motor built or not to the edge on pump is dumb. Just like running 20lbs, pump gas and a bunch of timing is not the way to run 20 lbs. Now on race fuel and more timing on the same setup is they way to do it. I went with the lower comp pistons so I could  run a little more boost and timing on the streets safeley. <------------- key word right there.


Im running the same pistons in my ls. This bitch is not bad at all. Its pretty quick. Its got way more tq than any n/a b-vtec motor Ive ever had. I think alot of it has to do with it being a fresh motor. All in all dont go for a HP number. Because you could go to one dyno and make 350hp, and go to another and make 290 on the same setup. Dynos are used as a tuning tool. Ive know guys that only push 300whp and they go to the track and run 11's Ive also know guys to go to the track with 450whp and run 13's all day long. Look at d16y8-z6 old build 315ish whp and LOW 11's.

[silverac]

i agree when it comes to longevity but to build a motor and dump all this cash just to walk away with 350 whp  when i know dudes making close to that on pump with completely stock motors almost makes u feel like it was a waste of money.

Then dump race gas in it and turn the boost up. 

I don't see what the problem is?  It's a limitation of the fuel, not the engine.

hey i wouldnt have a problem with the race gas if there were enough gas stations with race gas. i only know of 2 out in my area. and i mean there like a hour from each other, id hate to get stuk cause i cant find a gas station with race gas. ill do more research on that tho its gota be more. i had planned first to do 2 ( one on pump and one on race gas) maps but then comes the issue with the leftover shit in the gas tank. here comes a dumb question , can u drive around on race gas with no problems( i would think so)

[Joseph Davis]

Pump gas ignition timing and injector pulsewidths are exactly the same as racegas ignition timing and injector pulsewidths. 

Until, that is, you exceed the cooling (octane) of your fuel and the required ignition timing starts dropping really quickly because the fuel is basically trying to explode - which is exactly what I'm trying to tell you not to fucking do, which is what all the 400-500 whp pumpgas heros do with their $5000 engines that last 8K miles tops.

Tune the car on pump gas to ~350 whp, then dump a tank full off racegas and turn up the boost.  Afterward, when you are out of racegas just turn the boost down.  It's not hard dude.  You're overcomplicating this.

[silverac]

Pump gas ignition timing and injector pulsewidths are exactly the same as racegas ignition timing and injector pulsewidths. 

Until, that is, you exceed the cooling (octane) of your fuel and the required ignition timing starts dropping really quickly because the fuel is basically trying to explode - which is exactly what I'm trying to tell you not to fucking do, which is what all the 400-500 whp pumpgas heros do with their $5000 engines that last 8K miles tops.

Tune the car on pump gas to ~350 whp, then dump a tank full off racegas and turn up the boost.  Afterward, when you are out of racegas just turn the boost down.  It's not hard dude.  You're overcomplicating this.

i was trying not to complicate shit by just doing pump cause i have no experience with the race gas. so what ur saying is tune it on pump then fill it up with race and up the boost( all this on the same map) and when i run out of race just turn the boost back down.