nicksevo

i posted this is the forced induction area also so if i cant have it here you may remove. but i figured it also belonged here because it is a lt1 motor

I just had some questions regarding boost and compression( probably beat to death and I’m sorry but I just cant find any awncer that no one argues with). so ile start off saying this will be street driven with a few runs to the track. Also I am not looking for some monster 1000 hp car just trying to get a nice 10 or low 11 car. 475 hp(rwhp) 3500 ish lbs =11.35 ish so its around my figures but like always more power =more fun lol and that’s with a perfect driver and blah blah blah.

I am looking into buying a car on here and I like the car but I am kind of concerned about the build. he said the rings where gapped to be sprayed( is the gap the same for boost? i dont quite understand how rings are gapped or diffrence between boost and n20 gaps) but he said that he has a v2 supercharger he was going to sell with the car and it should be able to handle the boost( but I believe compression is to high 11.5:1). the mod list is as follows.

383 LT1 out of 94 camaro. It has Je pistons, scat crank,H beam rods, arp main studs and rod bolts. Comp cam, advanced induction heads, bowtie roller rockers,screw in studs,arp head studs copper head gasket,gm performance intake 750 Holley. said it made 475 hp to the rear wheels all motor(through a th-350 trans 3.42 gears). that’s the first thing that threw me off because I was like man for a motor to be boosted it seemed like alot of n/a hp.

i will be removing the intake and 750 and putting it back to efi( right now its carbed). I asked and he said he believes the compression is 11.5:1 which seems very high for something that I would boost but I am also not from the LS/LT world so I have no clue if that is to high or it would be ok.( more from the tunner area now stepping it up into a boosted v8 hopefully soon... but low compression and 30lbs is always what I knew lol no power until u where spooled up.. seems to be v8s are a lot different)

now if the compression is to high what would you recommend doing to drop the compression that could still keep me in a descent budget? new heads( any cheap heads that will drop it while still being efficient)?

if the compression stays that same what kind of boost levels would I be able to run without compromising reliability? and is the rotating assembly well built for boost( obviously not the dish on the piston) but I mean as far as handling power do you think there are things I should change or should this give me around 630-700 whp reliably or what should I change. I don’t know if the rods are good for tinsel str.( higher rpm) or compression( more boost) same for the rest of the rotating assembly.


Thanks a lot to everyone who posts and try’s to help out and trust me ive been searching using Google for the past hour or so trying to reassure my self that it will work but some people say yes and others say no way so I am confused and hopefully I get some good information on here.

Thanks a lot NICK

gregrob

iTrader: (8)

Boost away with GOOD fuel

nicksevo

saying good fuel i will be using 93 ..cant beleave i forgot that lol also have a meth kit i wouldent mind putting on it. ( some of the most important things to keep from knocking and i left them out.)

Rob94hawk

iTrader: (1)

I think he meant good fuel like VP C10 or better.

http://www.vpracingfuels.com/vp-drag-racing.html

nicksevo

yeah only problem with that is there is one station and its like 40 ish miles away and they have km2( whic is 110 i beleave) i was going to dailyish( not rilly every day) but i was wanting to just be able to fill it with 93 and be done with it.

gregrob

iTrader: (8)

Yes, I meant better than 93 octane...

My buddy boosts that compression hard with E-85; I would NOT try it on a lesser fuel...

nicksevo

Even if it was a low boost? And how would u go about droping the compression would the only way be to swap for lower compression pistons? Or is there a cheaper alternative? And they would build a motor to spray with this high compression? I figured spray was just as bad as boost on a high compression motor.

bowtienut

iTrader: (1)

I wouldnt put any boost on the engine you described. It sounds like a helluva NA motor, and would easily put an F-body in the high10's/low11's if you get it dialed in.
Nitrous would be no issue at all with that compression.

nicksevo

Haha well its in a 74 nova... but I just wanted a nice hi hp car...might just go turbo ls1 I guess haha.. this just seemed like a nice deal... but I need more than 475. Just don't think that will cut it for me when I can get a forged ls1 and easily break 600 with a turbo kit. Might just be to hungry for power you could say but I know I won't be happy with only 475. I figured puting boost through it would just make it a higher compression motor..like a 9.5 : 1 with 18lbs is fine so I figured that's so much pressure its gota be over 11.5:1 with a little boost...I know my logic must be just off lol

forgedlt4

I am running a 383 LT1 with 11.3:1 compression ratio. My motor made 400/400 rwhp /rwtq NA

I am running E85 and 7 lbs of boost currently. Im running a blow thru carb, no intercooler, with timing LOCKED at 22 deg.

http://www.youtube.com/watch?v=8hfBNqPv49c

Something is up with the motor making power though, as it peaked HP at 4500 rpms.... but it made 531/629 rwhp/rwtq. It might have been because it was running WAY too rich (mid 10s AF) But it runs and drives just fine, and i have ran it hard all last summer.

nicksevo

Yeah sounds like a funky power curve...but that's pritty sweet...would u recomend a blowthrough or go back to efi? I can get e85 although I was hoping to just get it to run on 93 because of simplicity...idk seems like I might run into a lot of headakes trying to get this high compression motor to take boost right. Might just not get it and find another forged ls1 or something...unless there is a easy wayy of droping compression without tearing the pistons out of it.

The owner just seemed comfident that it could take the supercharger well...he said it was brand new so I know its never had boost on it before...but I figured that it was built for boost but making that much power n/a confused me as well..like I said I'm from a tuner world lol its low compression tons of boost so I never see n/a numbers that hiigh usualy

forgedlt4

The only reason i made the switch to a carb, was because my wiring harness was all torn up, so i ripped it all out.

you could throw a thicker head gasket on it, its not the best option though.

you need to figure out your dynamic compression ratio, and it will help you to see what you can safely run.

nicksevo

Its a car I am planing on buying is the problem lol...using a compression teter is there a way I can come up with a compression figure ( ex. 10.0 : 1. Or 9.5:1) or would I have to know the whole formula to do it? Is there a easy 185on the gauge is 11:1 ( just a random number)figure or something lol.

RamAir95TA

iTrader: (2)

Compression ratio is dependent on physical dimensions (bore, stroke, head gasket thickness, etc.), not cylinder pressure.

Just out of curiosity, why don't you keep things a bit simpler, use what you have, and make the most out of it N/A? Save some money and still achieve your power goals.

nicksevo

well because the supercharger comes with the car for a very good price so i figured with a bolt on and some tuning i could have a 550+hp car for a very good deal. and rilly i love the wine of s/c's heck i miss the spooling of my evo( now i drive a little sl1 bone stock automatic lol) even the evo made over 450 hp and i wasent happy with it.. it was quick but just not the umph i wanted ..

and while i am talking to u i was interested in your car also lol... but same thing i think i am going to miss the feeling and sound of boost...might just have to put a wistle in my intake lol. i bleave you where the lt1 car that was for sale i was looking at for some time. ive been lurking the forsale threads everyday but geting a nice classic that can move down the track with my buddies would be nice( i love classic muscle) but it needs to have the grunt to make me happy at the same time. i just feel without boost i wont be happy.

and i guess a 475 will move me down the track just seems so small compared to all the boosted ls1's going into the 650+hp range very easily i am seeing( through the time ive looked ive seen a lot of nice ones for 12-17k) which is a very good price for that much power because if 475 hp is going to go a 11.3 -11.5 i just cant think of what havin 650+hp is going to be like

97Z28SS

iTrader: (5)

Well I will say this as I have a Procharged blowthru carbed 383 in a Monte Carlo SS and I'm not like most forced induction followers as I don't follow the standard mantra (run low compression and boost the hell out of it). My motor is 10.5:1 scr and I'm running 13#-14# of boost. But I have a big A2A intercooler and water/meth with timing retard. So the thing to remember is as the scr goes up the amount of boost must come down to run on 93 and you definately need to be intercooled and run a water/meth kit to be safe. You'll also want some sort of boost timing retard.

bowtienut

iTrader: (1)

I suggested that earlier, based upon his stated mild ET goals, and from his response I realized he really doesn't have an ET goal. He wants a dyno number and that topend punch.
No offense meant, OP, but with these cars/engines, you can actually leave the line hard, unlike the small revvers you're used to, so it doesn't take a high hp topend charge to run a given ET.

nicksevo

Maby I'm just used to the hp to pull me through the end and I want more of a street dominator than a 1/4 car... everyone I ride with is high top end power and feel like they would pull my pants down on the freeway if alli can do is leave hard. Not saying a nice 10sec pass won't make me grin ear to ear just I don't want to be limited to the launching off of the line hard ide like to stick it to the floor on the freeway and feel like I'm in a 10 second car. But I've road in a ls3 camaro that put down a 11.1 pass but on the road it just doesent have the grunt/ tq I was hoping for.( I beleave that pass was a bad traction / 60 also). I am not shootin for a dyno queen but I guess I havee to ride in a n/a car that puts that much power down to see how it gets up.

Also are there any other heads I can put on that would get me down to the compression I can properly boost at? Or a combination of head,, gasket, anything without getting into the bottom end again? And just to clarify why I want boost is that the car will come compleat with a full v2 supercharger as a nice package price

Also as far as n/a what elce could I do to get me where I want to be? I figured lt1s where at the top of there n/a limit with 475-500 and still be streatable with 93 oct. Idk what cam it has in it because its not specified but I figured the only thing to do is boost or juice..and I've never been a fan of n20 ( not saying I hate cars with it) just not a fan of it for the fact I'm scared of it hurting the motor and running out ( where as boost never runs out)

You can correst my knowlage as it is not at the top of the list talking on this forum... kinda a newb to building v8s for sure so any info u have would be great. And thanks a lot for all of it so far.

Wicked94Z

iTrader: (26)

throw a thicker head gasket on it, and use a meth kit

nicksevo

I don't rilly want to bandaid it ide rather fix it so I know I won't push a thicker gasket out or. Have anyy future problems handeling the power...if I can squeese more out of it n/a to put me around 580+ for a reliable car that I can put pump gas in and go would be great but I don't think its a resonable number for it to make n/a although if it can be done I would like to know how