c-speed's compression calculator puts my setup at 12.3:1. My question is is this too much for a daily driven ls vtec? I was going to go with regular pr3 pistons, btu have a great deal on some ctr's...but I don't have access to a dyno or a tuner. It'll be tuned with uberdata, but I don't have a wideband, so it won't be tuned very well. for CTR's?

 

unless you have access to at least 94 octane gas it is too much for an untuned ls/vtec

 

I disagree, I have CTR pistons in my daily driven LSVTEC. If you need any info PM me.

 

werd, 93 octane is good up to 12.5:1 or so....I forgot where I read it or Id post it....

 

Yep, it is.

You can even shave the points off the top of the piston, to lower the compression some.. Thats what I had done.

 

This is probably the most infamous question about high comp honda pistons, everyone i seen that has ctr's make good power, but just watch the fuel, all the people sportin' ctr's that i know out here in cali run a 1 gallon 100-110 octane gas blend with 91 octane! it works well considering we have shitty gas! 91octane

 

that sucks...so its realy just a matter of opinion. I'm not really going to get a straight answer. Who is actually running CTR pistons on 93 pump gas? I have access to 93 here in OK.

 

ctr's if your on pump gas
i would not go over 11.5 on pump gas
just get some pr3 or p30 or jdm itr pistons

 

I don't get it then...why would civic type r's require more than 93 octane? can't ITR's run on 91? whats the stock comp ratio of CTR and ITRs?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Slimm-rw- &raquo;</TD></TR><TR><TD CLASS="quote">that sucks...so its realy just a matter of opinion. I'm not really going to get a straight answer. Who is actually running CTR pistons on 93 pump gas? I have access to 93 here in OK.</TD></TR></TABLE>

I am running CTR pistons and an ITR head, I use 93 pump gas, no big deal.

 

That's what I'm going to run.

CTR .25 over in LS block with PR3 head on 93 octane.

 

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by riceball777 &raquo;</TD></TR><TR><TD CLASS="quote">ctr's if your on pump gas
i would not go over 11.5 on pump gas
just get some pr3 or p30 or jdm itr pistons</TD></TR></TABLE>

this is a mis informed post. Don't listen to this.

 

you just need more fuel and less timing for daily driving ... so you use 1 map for that and another more aggressive map for racing. Try to use a mild cam, like at least a toda A, sk2 stg 1, crower stg 1, etc.
evne ctr or itr cam is decent i guess but the bigger cam the less dynamic compression = lower octane fuel you can use. I know some states its hard to find and afford 93 octane, so people suffice with 91 octane.

I just paid $2 buks a gal for sunoco 94


greg

 

i just paid 1.98 for mobile 93. damn

 

Our gas is 2.30+, just for 91 oct.........

 

in stillwater I pay about 1.8 to 1.90 for 93, in tulsa sometimes its down to almost 1.65...so its affordable. and I hope I can pull off that compression ratio, because I just bought those pistons.

 

go for it man you should be ok on pump gas

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Slimm-rw- &raquo;</TD></TR><TR><TD CLASS="quote">but I don't have access to a dyno or a tuner. </TD></TR></TABLE>

Get w wideband o2 sensor/gauge, learn how to street tune with a good A/F gauge...

 

12.3:1 compression ratio on 93 octane with .25 oversize CTR's.....Im living proof! lol

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LSVTEC 91 Civic &raquo;</TD></TR><TR><TD CLASS="quote">
Get w wideband o2 sensor/gauge, learn how to street tune with a good A/F gauge...</TD></TR></TABLE>

what he said. i read a post on here that said up to around 12.5:1 is ok on 91 with good tuning, and i read another that said anything higher than 11.5:1 won't be safe. i personally plan on getting a wideband, and street tuning right in the middle, about 12:1 comp in an ls/vtec.

ps. i also read somewhere that c-speeds compression calculator isn't very accurate.

 

i ran 12.5:1 JEs in my GSR motor all dam day on 93 octane no probs..period!..and i know a few other guys that have done the same ..

 

i am running pr3's in mine and i am starting to have a ping below 2000 rpm's. the engine hasnt been tuned yet so im sure it will go away when it is tuned. and i run 91 since that is the highest we can get here.

 

Sounds like you need to adjust timing..

I'd set the distributor placment to stock, set the cams to zero.

I have my exhaust cam retarded -1, and the intake cam advanced 4.

 

i have the intake cam 2 degress advanced and the exhaust at 0. the distributor is set at stock also. i have retarted it damn near all the way and advanced it all the way and it still doesnt effect it. and when i slam the pedal to the floor it jumps then hesitates before going again.