Im building an ls/vtec right now and i got a question, not too sure if its a dumb question, and i did research before i posted this lol.

Head:
gsr head
itr valvetrain
itr intake cam
gsr exhaust cam
Aftermarket valves, not sure yet which ones yet

Block:
b18b1 81mm, might bore to 81.25
p30 pistons oem rings
ls rods
ls crank
oem main and rod bearings
ls head gasket
gsr oil pump
gsr water pump
gsr t-belt
ARP rod bolts and main and head studs


My main question is about my CR, this will be my dd so i want to build it right the first time, will this setup be all good for DD? i tried the compression calculators but im not too sure if they're legit.

all suggestions welcome! thanks

 

Your compression ratio will be about 11.8:1 I believe, I know PR3's with GSR head equate to 11.6:1.

Don't bother getting ARP mains, not worth the money for machine work needed, plus factory mains are highly unlikely to fail.

 

im halfway through putting together my engine, very similar to yours except im using a pr3 head. all my research showed my cr of about 12:1. i think it will be ok to daily drive if you use 93 octane and have a good tune. very well could have to pull a few degrees timing below 5" vacuum.

3 things you might want to reconsider

1) aftermarket valves are not necessary. ive been beating the crap out of my oem valves in my 500hp turbo engine for years 9000 rpm limiter at the track with no problems.

2) as already said, save the money and not use the arp mains. not necessary.

3)ive seen some oem retainers fail above 8400-8500 rpm. might want to consider an aftermarket retainer if you plan on going higher than that.

good luck, definitely curious to see the results

 

Ok thanks a lot. I was just gonna put in the main studs just for some extra insurance. I really wanna stick with oem right now just for reliability so I'm gonna try and clean up the stock valves. I'll keep in mind about the retainers. I'll research some companies for them. What exactly do u mean with the timing? This is my first build so If u wouldn't mind what possibilities I'll run into that would be awesome lol

 

You have to get an align hone and the main stud holes bored to use them. Like I said, don't bother.

And if you are going to reuse valves, atleast lap them in.

 

alright thanks for the advice man. really helps. absolutely, if i decide to reuse them, but im pricing out brand new valves through my job so ill see how that goes. im sending my head to the machine shop soon to get it all cleaned and checked out, and also a valve job too.

 

I wouldn't be looking into new valves if you are already getting a valve job. It would just need to be done again.

 

I'll see how they look when I remove them in the next week or so. I'll go from there

 

What calculator are u using to come up with this 11.8? I want to give it a try.

In the few highest load columns the ignition timing could have to be retarded to avoid detonation. From what I've been seeing you could likely wind up with 24 to 26 degrees total timing at wot which is much closer to p30 maps than a p72 map. The final outcome can only be determined on a dyno, but that just seems to be ballpark from what I've been reading on here. Also for a dd might want to have wot afr around 12.8 -13.0:1 rather than 13.2-13.4ish. Again, it can only be exactly figured out on a dyno

 

alright thanks. ill keep that in mind. i app it. the only one i know of in the zealworks compresison calc.

 

I'm not sure if that's right, that's just a number off the top of my head from reading up on LSV builds and such.

 

Ok. I'm always looking up builds and researching for something new for some ideas