I am sending my block off tomorrow to get built and I'm still not sure if I want 84mm with 11.9:1 84mm or 13.6:1 compression with 85mm bore

This will be my GSR block with built Toda GSR head (spec B's)

Can I run 93 octane with the 13.6:1 compression?

 

First off, that amount of compression is well beyond what is required for Toda B's. With those numbers I'd expect to see you running far crazier cams than that, Maybe the Jun 4's. High compression on pump gas all depends upon how well you tune it, but I don't know that any amount of tuning will keep you safely away from a lot of octane boost. Being that the car is a street car, I'd drop the compression a bit.

 

do you think toda specs C's would do the trick?

 

Definitely go with the 11.9:1. 13.6:1 is insanely high and you won't be able to do it on 93 octane. Just make sure you get tuning done and you'll be fine with the 11.9:1.

 

I think 11.9 should do well and retain the essense of streetability. I think at this point you really need to sit down and do some research.

 

I would run the lower compression if you want the car to be streetable. with 13 point whatever for compression, the cams are going to be so wild that you will have a very high idle, sucks when you are in traffic, trust me!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93ludeSi &raquo;</TD></TR><TR><TD CLASS="quote">with 13 point whatever for compression, the cams are going to be so wild that you will have a very high idle, sucks when you are in traffic, trust me!!</TD></TR></TABLE>

Not true
There are tricks to running 13.6:1 and big cams. It's all in the tuning.

 

doesnt big cams like toda b's drop dynamic compression? it is possible to run it that high. i hope u have a hondata

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b19coupe &raquo;</TD></TR><TR><TD CLASS="quote">

Not true
There are tricks to running 13.6:1 and big cams. It's all in the tuning.</TD></TR></TABLE>

oh no, i am not saying that it's impossible, just not as easy as building a slightly lower compression motor. All depends on how much you want to spend, how drivable or fast you want it to be, and how reliable you want it to be. like they always say, pick two cheap fast relaible

 

But with cams like the spec B's, you'll be undercamming the engine with that high of a compression. You'd be increasing your cranking pressure by FIFTY percent. Mike Delaney over at TI says anything over 25% and the high end becomes blunted. But the bigger the cam and higher the ABDC, the higher you need to raise the static compression in order to make up for the loss of cylinder pressure you'd encounter as compared to stock. Do your homework before buying anything.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b19coupe &raquo;</TD></TR><TR><TD CLASS="quote">

Not true
There are tricks to running 13.6:1 and big cams. It's all in the tuning.</TD></TR></TABLE>

oh no, i am not saying that it's impossible, just not as easy as building a slightly lower compression motor. All depends on how much you want to spend, how drivable or fast you want it to be, and how reliable you want it to be. like they always say, pick two cheap fast relaible

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eyeamvic &raquo;</TD></TR><TR><TD CLASS="quote">Definitely go with the 11.9:1. 13.6:1 is insanely high and you won't be able to do it on 93 octane. Just make sure you get tuning done and you'll be fine with the 11.9:1.</TD></TR></TABLE>
I second that.
If you are running 13:6:1, it is hard to run 93 octane(Hard to run on the street for that matter especiallly if daily driven).If you choose the 11.9:1 pistons, 93 can be possible with the correct system (hondata s200) and good tuning. I am runing 12.5:1 pistons in my b18c1 and I use nothing but 100 octane to lower chances of detenation. Definetly, go with the lower 11.9:1. About the cams, if you are running the ratio of 11.9:1, you could still use the toda b's. 13.6:1 would need the aid of the higher profile spec c cams though.
Good luck with the set-up.
Ryan
Thanks,
Ryan

 

i would stay under 12.5 for pump gas.

 

Me personally, I'd be afraid to run anything over about 11.5:1 on 94, but I don't know anything about tuning. If I had an awesome tuner I'd go 12.5:1.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by -KangaRod- &raquo;</TD></TR><TR><TD CLASS="quote">Me personally, I'd be afraid to run anything over about 11.5:1 on 94, but I don't know anything about tuning. If I had an awesome tuner I'd go 12.5:1.</TD></TR></TABLE>where i live the got rid of 94 ...but ive heard of people running 13.6.1 on 94-93 but keeping it to half throttle and running like 100 or 105 on races days ...

 

I have 13.1 compression, toda c and run fine with hondata. I have no problems running on 93. NGR tuned...

 

where u sendin it to get it built?

 

all these guys are pretty much on the dot
and since u are planning to drive it on a daily bases then stay 11:9:1

right now with the gas prices like they are u better stick to lower then 100 octane

I am running 11:8:1 pistons
and use 91 in so cal
cuz that is all i can get pump
unless well u got that much funds for 5 plus a gallon for the 101 octane pump

and well can someone like him use the jun 3's
I am trying to figure what cams to use for my set up at the moment
my itr cams suck ***???

but get the 84mm 11:9:1 pistons for sure, bro
good luck
and keep us posted

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM2ndGen &raquo;</TD></TR><TR><TD CLASS="quote">where i live the got rid of 94 ...but ive heard of people running 13.6.1 on 94-93 but keeping it to half throttle and running like 100 or 105 on races days ...</TD></TR></TABLE>

yeah sonoco replaced 94 with super 93..WTF

running 13.X compression will require some serious tuning...if you have a reputable tuner then do you...other than that...i would stay in the 12 region unless you are brave...

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 91integraLSVTEC &raquo;</TD></TR><TR><TD CLASS="quote">doesnt big cams like toda b's drop dynamic compression? it is possible to run it that high. i hope u have a hondata</TD></TR></TABLE>

ive always thought about that...when you have huge cams..i think you loose dynamic compression..maybe that will help prevent some detonation. I dont know..but TODA B's are considered small on 13.X compression ratio u need some TODA D's JUN 4s or those EF-1 cams

 

ive run as high as 14:1 on 93 octane.
if you can tune it, it can work.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sgT &raquo;</TD></TR><TR><TD CLASS="quote">ive run as high as 14:1 on 93 octane.
if you can tune it, it can work.</TD></TR></TABLE>

and rev it to the red line??

 

i am on 11.8 pistons gsr head, rebore crv crank i was caculated at 12.3:1 running 91 on non pro. tun job

 

hmmm...anyone's opinions on a 12.5:1 81.5 mm bore ls/vtec with a set of rocket m24's on 93 octane?

 

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

and rev it to the red line??</TD></TR></TABLE>

 

I just think that daily driving up a hill or somthing is going to be your biggest enemy when it comes to detentation