Mr. Softee

I hadthought my LS motor was 10:1 compression, it is more near 10.8:1.

I have an EXTENSIVELY ported head, shotpeened stock rods, 10.8:1 compression.

Could put a blockguard/arp head studs in.

Asuming very easy timing, and a 12:1 a/f ratio, how much boost or how much power can this bottom end take? Im talking for a few passes, not every day.

And how much power should I dial in for daily? How much timing should I take out for 91?

I am irritated my compression is this high, but hopefully it will yield good results like the ITRs have with low boost.

Mr. Softee

im running uberteg's software, zif socketed ecu, and i have a DIY wideband. So asuming i can tune real well.

94TealGSR

Bump, because my GS-R motor has the same compression and I wanna know the same thing.

kb58

What cams are you using? They matter because if there's overlap, your effective compression will be less than the static compression.

Mr. Softee

stock

sweet

iTrader: (5)

hmm, so what pistons did you (or someone else) put in there to make it 10.8:1 C/R?

10.8:1 C/R really isn't that bad for turbo, as long as the tuning is done very carefully and correctly. but you have to be careful since you're using stock rods.
if you're using the stock B18B cams (i think that's what you stated) then the overlap shouldn't be too much, which is good for turbo but will keep the C/R about the same instead of lowering it like if you were using longer duration cams.

tuning is the key and you can't expect much reliable power from a motor using stock rods (and maybe OEM cast pistons too). i would forget the blockguard thing but definantly go with ARP rod bolts and headstuds. higher C/R needs more precise tuning but allows you to run a bit lower boost level and make the same amount of power, so it's really not that bad.

Mr. Softee

I realize the importance of tuning. Im hoping the questions I asked will help me understand how to tune this motor best.

Mr. Softee

E-Rok

10.8 isnt bat at all. i wanna go with something like 10:1 when i built up my LS.

Tinker219

10.5:1 here Probably higher with a B16a head. The JEs are 10.5:1 anyway, and are for the LS....

Mr. Softee

BoostedsiR

thats a lot of compression especailly for a LS... if I recall ls is 9.5:1 why did you make it so high and why dont you stay N/A but if you want to boos get a good thick head gasket studs and cam gears for tuning and boost like 7-9 psi I would say **** that blockguard ****, it doesnt do a thing. you should even consider to lower your compression but if you think that you are good then more power to you bro

MiraiZ

Personally, I'd be very careful...its not that the compression is too high, its more that the ringlands on stock pistons are very weak...get it tuned right away, and don't get carried away with boost unless you plan to rebuild in the future...

Mr. Softee

omg people please read... i am tuning this myself just looking for tips in the areas i asked.

ekb18c

If you tune it right you can get 400whp on that baby(race gas). For daily use that to get at least 325whp. (pump gas)

Tuning is the key.

sweet

iTrader: (5)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94goldjungsr &raquo;</TD></TR><TR><TD CLASS="quote">I hadthought my LS motor was 10:1 compression, it is more near 10.8:1.

I have an EXTENSIVELY ported head, shotpeened stock rods, 10.8:1 compression.

Could put a blockguard/arp head studs in.

Asuming very easy timing, and a 12:1 a/f ratio, how much boost or how much power can this bottom end take? Im talking for a few passes, not every day.

And how much power should I dial in for daily? How much timing should I take out for 91?

I am irritated my compression is this high, but hopefully it will yield good results like the ITRs have with low boost.</TD></TR></TABLE>

just to go back and cover each area:

10.8:1 C/R is fine for turbo, tuning is the key really.

a ported head for turbo and shotpeened rods should also be fine for turbo.

skip the blockguard but go with ARP rod bolts and head studs.

i'm sure it could take 10# of boost easily (for occasional use at the track etc), and more depending on the tuning, usage and fuel.

i'm not sure on the tuning since that isn't my area, but being conservative on the ignition timing would be the way to go.

with almost 11:1 C/R you'll only need lower boost levels to hit 300WHP.
a stock USDM ITR with 10.6:1 and 8# of boost on a T3/T04E can hit 300WHP, which i've seen before. i know the cams and head are different on the ITR compared to the LS, but i'm sure your motor will make good power.

yimmy

So your saying if we have a high c/r we dont need to run very high of boost. I am running 10.5:1 and was thinking about turning the boost to 20+. Is that a bad idea?

94dxt

10:5 + 20psi. that's a lot of f'n power. you would definately need veeery precise tuning and strong *** internals

yimmy

so be it...now I just need to find a good tuner

yimmy

Can you guys help me out before I crank up the boost. Do you think there is anything else I need so I dont blow it up.

97 Ls block and head
Crower Rods, JE pistons and rings C/R 10.5:1
Custom Sleeved and Pinned Block
Knife edged and micro polished crank
Head is ported, 5 angle valve job, titanium retainers, titanium valvesprings
Ported intake manifold, TB
Sds fuel system, custom fuel rail, 6btm msd with timing computer
Fluidyne Radiator
To4E turbo, custom equal length mani., type r bov, spearco intercooler, delta wastegate

sweet

iTrader: (5)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by yimmy &raquo;</TD></TR><TR><TD CLASS="quote">Can you guys help me out before I crank up the boost. Do you think there is anything else I need so I dont blow it up.

97 Ls block and head
Crower Rods, JE pistons and rings C/R 10.5:1
Custom Sleeved and Pinned Block
Knife edged and micro polished crank
Head is ported, 5 angle valve job, titanium retainers, titanium valvesprings
Ported intake manifold, TB
Sds fuel system, custom fuel rail, 6btm msd with timing computer
Fluidyne Radiator
To4E turbo, custom equal length mani., type r bov, spearco intercooler, delta wastegate </TD></TR></TABLE>

that setup sounds great, should hold high boost very well. but of course tuning needs to be done very carefully.

BTW what are you gonna use to actually tune the car? Hondata or standalone system etc?

yimmy

I have Sds em-2 as my engine management. And I have no one around me that knows how to tune it

blundar

Unless I misunderstand your setup 94goldjungsr, the limiting factor will be your rods. Honda B series rods are generally not known to withstand more than 250hp, particularly repetitively, without having real issues.

Also, if you have a 10.8:1 compression ratio due to ITR or GSR pistons, you probably want to invest in a set of forged pistons.

With a stock MAP sensor, you are going to be limited to around 10.5psi.

Why don't you give us more details?

sweet

iTrader: (5)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blundar &raquo;</TD></TR><TR><TD CLASS="quote">Why don't you give us more details?</TD></TR></TABLE>