tobe1424

Just looking around and still havent found anyone with the following setup.

stock block with aftermarket rods and 9.8:1 wiseco pistons on about 10 or so psi.


I mean everyone boost there stock gsr's that bring more compression than that...so Im guessing that setup on a torquey b18b should be potent


well just hit me back with some feedback and what you guys think about that combo?

adseguy

Compression doesn't do nearly as much as VTEC and the better head flow/IM...etc. Go lower compression and add a lb or 2 to compensate IMO.

tobe1424

You are right....but the couple points of higher compression will make the motor not feel as laggy when you step on it....and duh its not going to be like vtec...but come bit of power...and i dont want to go high boost either...its going to be a dialy driver

adseguy

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tobe1424 &raquo;</TD></TR><TR><TD CLASS="quote">You are right....but the couple points of higher compression will make the motor not feel as laggy when you step on it....and duh its not going to be like vtec...but come bit of power...and i dont want to go high boost either...its going to be a dialy driver</TD></TR></TABLE>

You know how much power you are talking about? Boosted-hybrid (Jeff Evans) did a comparison between a 9.0:1 and a 10.0:1 compression motor on the dyno and only founf 10whp (or so) difference. If that's enough for you...great go for the higher compression. I just like the added safety from a bad tank of gas or a little more le-way in the tune.

Also, the amount of boost has absolutely no bearing on reliability. Proof in speaking I had 16-18psi stock everything for 1.5 years and it's still runs (if it was in my car ).

Bjorn20

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tobe1424 &raquo;</TD></TR><TR><TD CLASS="quote">Just looking around and still havent found anyone with the following setup.

stock block with aftermarket rods and 9.8:1 wiseco pistons on about 10 or so psi.

so Im guessing that setup on a torquey b18b should be potent

</TD></TR></TABLE>

that setup should be fine. again you will hear it 904219348921372198 times, it really doesnt matter how high your compression is in the relation on how much boost. As long as you did the build right to begin with, a good tuning setup (chipped ecu/engine management system, boost controller) and someone that can to the tuning for you, it should be straight.

just think the "torque ls motors" line is funny. Cause i mean its a tiny 1.8 liter and us honda freaks think thats a **** load of torque. lmao i just think thats funny, if you dont oh well thats fine

tobe1424

This is my theory...why does it take for example an srt4 14psi to have 230whp stock....and why does it take a stock LS not even 10psi depending on the tuner. Note, the dodge neon r/t makes tons more power than a LS....but why does it take an Evo 22 pounds to make 300whp.....? Because of there low compression pistons!!!.... I dont want a drag car i want a pretty decent fast car with good throttle response....

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bjorn20 &raquo;</TD></TR><TR><TD CLASS="quote">

that setup should be fine. again you will hear it 904219348921372198 times, it really doesnt matter how high your compression is in the relation on how much boost. As long as you did the build right to begin with, a good tuning setup (chipped ecu/engine management system, boost controller) and someone that can to the tuning for you, it should be straight.

just think the "torque ls motors" line is funny. Cause i mean its a tiny 1.8 liter and us honda freaks think thats a **** load of torque. lmao i just think thats funny, if you dont oh well thats fine</TD></TR></TABLE>

Lol yea for us honda guys 150ft/trq is like crazy....wonder what the v8 guys think of us lol.

Jockobo

those cars have smaller turbos than what honda guys usually run...hence the low power output at high boost

tobe1424

well yea you do have a point...but its not that big of a difference...come on you put a dsm turbo on a civic and it will make some kind of power with less psi....or put the same size turbo as an srt on a b16 on 15psi and im sure it will make alot more than 230whp

bb_one

Making a straight comparison between DSM motors and Honda motors is comparing apples to oranges. Given that the difference in compression are there, you're forgetting everything else. Like head flow, cam profile, engine internals, VE, so on and so forth.

It's been beating to death that using PSI as a gauge for power is irrelevant. Calculating the CFM your engine needs to make X amount of power is more practical. Smaller turbos MUST build more boost to make up that X amount of CFM your engine consumes to make X amount of power. A bigger turbo will be able to flow more cfm then a smaller turbo, thus it does not need to build as much boost as the smaller turbo to make the same amount of power.

There have been many threads pertaining to what compression ratio is good and what's too high and too low. I believe it is up to your preferences and tastes. I have seen all sorts of boost setups using 8.1 comp piston to 11.5, running very nicely.

Some things sound very good in theory, such as high compression = better off boost response. Now that maybe so, but is it really real world practical where that "better response" is something we can actually feel? Personally, I couldn't see the difference and so do many other users on here. I chose to run 8.5:1 pistons because I sleep better at night knowing I have a higher knock resistance then something like 10.1:1 pistons. Although a competent tuner can make anything work, and work reliably.

It basically boils down to lower comp. having higher knock resistance, easier to tune with boost, and more room for error, so to speak. And of course to run more boost . With the draw back of not FEELING as responsive as high comp when "out of boost".

*edit*- Here is a thread recently started asking if 8.1 comp. pistons were too low of compression. https://honda-tech.com/zerothread/1737074

JDMs1eeper

those are some nice gains

who needs Vtec then, just up the boost

Before discussing compression ratio and boost, it is important to understand engine knock, you know... detonation. Knock is a dangerous condition caused by uncontrolled combustion of the air/fuel mixture. This abnormal combustion causes rapid spikes in cylinder pressure which can result in engine damage.


Knock resistance characteristics (knock limit) of the engine: Since every engine is different when it comes to knock resistance, there is no single answer to "how much." Design features such as combustion chamber geometry, spark plug location, bore size and compression ratio all affect the knock characteristics of an engine.

Ambient air conditions... For the turbo application, both ambient air conditions and engine inlet conditions affect maximum boost. Hot air and high cylinder pressure increases the tendency of an engine to knock. When an engine is boosted, the intake air temperature increases, thus increasing the tendency to knock. Charge air cooling (e.g. an intercooler) addresses this concern by cooling the compressed air produced by the turbocharger

Octane rating of the fuel being used... octane is a measure of a fuel's ability to resist knock. The octane rating for pump gas ranges from 85 to 94, while racing fuel would be well above 100. The higher the octane rating of the fuel, the more resistant to knock. Since knock can be damaging to an engine, it is important to use fuel of sufficient octane for the application. Generally speaking, the more boost run, the higher the octane requirement.

The compression ratio from the factory will be different for naturally aspirated engines and boosted engines. For example, a stock Honda S2000 has a compression ratio of 11.1:1, whereas a turbocharged Subaru Impreza WRX has a compression ratio of 8.0:1.

There are numerous factors that affect the maximum allowable compression ratio. There is no single correct answer for every application. Generally, compression ratio should be set as high as feasible without encountering detonation at the maximum load condition. Compression ratio that is too low will result in an engine that is a bit sluggish in off-boost operation. However, if it is too high this can lead to serious knock-related engine problems.

Factors that influence the compression ratio include: fuel anti-knock properties (octane rating), boost pressure, intake air temperature, combustion chamber design, ignition timing, valve events, and exhaust backpressure. Many modern normally-aspirated engines have well-designed combustion chambers that, with appropriate tuning, will allow modest boost levels with no change to compression ratio. For higher power targets with more boost , compression ratio should be adjusted to compensate.

There are a handful of ways to reduce compression ratio, some better than others. Least desirable is adding a spacer between the block and the head. These spacers reduce the amount a "quench" designed into an engine's combustion chambers, and can alter cam timing as well. Spacers are, however, relatively simple and inexpensive.

A better option, if more expensive and time-consuming to install, is to use lower-compression pistons. These will have no adverse effects on cam timing or the head's ability to seal, and allow proper quench regions in the combustion chambers.

tobe1424

Lots of good pionts there

But I mean, come one going with 9.8 C/R isn't too much...especially on an LS that revs 7K IMO....Isnt stock like 9.4 or 9.2 i forgot

Turbo-LS

iTrader: (4)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tobe1424 &raquo;</TD></TR><TR><TD CLASS="quote">Just looking around and still havent found anyone with the following setup.

stock block with aftermarket rods and 9.8:1 wiseco pistons on about 10 or so psi.


I mean everyone boost there stock gsr's that bring more compression than that...so Im guessing that setup on a torquey b18b should be potent


well just hit me back with some feedback and what you guys think about that combo?</TD></TR></TABLE>

Well the LS is not going to feel laggy. The 89mm stroke makes good bottom end and midrange power especially with the properly sized turbo for your goals of 10 psi. YEah yeah everyone always says go vtec blah blah blah. Eventually im going vtec in a few years but right now my ls is great and im going for 650+ on her with some good boost on the gt3567r

What your doing will be very enjoyable, yes its not going to make gsr numbers on 10 psi but you will be happy non the less. i was making about 300-330 whp on my ls last year with a t4/t04e 60 trim .69 a/r and the super t04e compressor wheel which is just a .200 inch larger exducer. yes its a fully built engine but they do make power. my buddy made 400 and some change on his ls with forged internals. everythign else was stock, the head, the cams, the intake manifold and it was obd1 manifold which suck and with an ebay turbo

JDMs1eeper

haha... my last 2 setups:

84mm B18b nonVtec turbo @ 26psi
10.0:1

84mm LSvtec turbo @ 26psi
10.5:1

The LSvtec made 366whp & 274 @ 10psi stock B16A cams

Get ur stuff tuned and you'll be plenty fine. My first rods/pistons setup was about 8.5-8.8:1 and it was a slug out of boost.

PM-Performance

9.8:1 isnt high compression. youll be fine.

awdgsx96

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tobe1424 &raquo;</TD></TR><TR><TD CLASS="quote">This is my theory...why does it take for example an srt4 14psi to have 230whp stock....and why does it take a stock LS not even 10psi depending on the tuner. Note, the dodge neon r/t makes tons more power than a LS....but why does it take an Evo 22 pounds to make 300whp.....? Because of there low compression pistons!!!.... I dont want a drag car i want a pretty decent fast car with good throttle response....

</TD></TR></TABLE>

I'm not trying to start a DSM&gt;Dodge&gt;Honda battle, but for one, you have to take into consideration the the size of the turbos. You also have to remember that yes the engine is boosted, but still needs to meet safetly and emission regulations, their tuned for a safe point. On top of that is the smaller intercooler piping, along with the OEM intake.

tobe1424

Good point there peeps....now all those setups have been on what tranny....im planning on going with a GSR but i think anything in the 250whp + area would be useful to have an LS due to traction problem....What do you guys think...yes ive searched for threads but i dont find specifically what i want to hear?

whiteef8

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

You know how much power you are talking about? Boosted-hybrid (Jeff Evans) did a comparison between a 9.0:1 and a 10.0:1 compression motor on the dyno and only founf 10whp (or so) difference. If that's enough for you...great go for the higher compression. I just like the added safety from a bad tank of gas or a little more le-way in the tune.

Also, the amount of boost has absolutely no bearing on reliability. Proof in speaking I had 16-18psi stock everything for 1.5 years and it's still runs (if it was in my car ).</TD></TR></TABLE>

I would like to see the dyno charts on both of these setups, peak horsepower is not what I, or he im sure, is worried about. I bet you the over powerband is much smoother and steady increase, therefore the lag factor. Personally i have a 10.4:1 LS/V and am going to be boosting it with an sc61 about 15 lbs, thinking it should be an absolute street monster. However youre very right about the bad gas and/or tuning possibilities, but i myself have confidence in my tuner, and will be purchasing lots of race gas to throw into my tank

to OP, i think that would be an excellent street setup, just remember to do your research, dont skimp on the important parts, and talk to as many different tuners as you can about your setup and how in depth you want to go (ie. which management to choose) good luck and let us know how it goes

tobe1424

Well Im going to eventually tune it with an AEM EMS with some guy Lance that supposedly is the man....and tuned a couple of 8 sec cars and has like 50 million certificates and ****....so hopefully that wont be a problem