wm5holla

pick one?

I've heard conflicting stories about running CTR pistons. I was planning on using them in my LS/vtec setup but in discussing that with someone who has built them before I was told the compression ratio would be to high (12.5 to 1) to allow for any type of adjustment using timing. You also would have to worry about what octane gas you are running. I was told that JDM ITR pistons would be better due to a lower compression ratio, around 11.8 to 1 if I am not mistaken.----civichopeful

civichopeful

Bump for quoting me.........

ExospeedAMcrx

the CTR's should be good.. its all preference.. the CTR pistons can still use pump gas as long as you arent milling the head or using a thinner head gasket. its safer to run the itr's since its lower compression... but doesnt mean the CTR's wont work in a daily driven car. for conservative drivers/racers.. go with ITR. if you are really into it and are willing to take a car to its limits.. then the CTR is for you.

Losrocket_

Im using GSR pistons in my LSvtec.

wm5holla

are u sayin that ctr pistons can use pump gas? what gas do the use? write back exospeedAMcrx)

Kataku2K3

It's whatever you want to do but I would go with CTR's, with an OE headgasket, no head milling, bored 0.25mm over, and the P72 head with the smaller combustion chamber (41.60cc's) you'll still be fine on pump gas... With my calculations and the parts above your C/R should be somewhere ~12.35:1 Sure you'll have to tune it but right now my friend is building a CRVTEC for his EG and it's going to be running 13.5:1 on 104 octane.... For engine managment he's gonna be running Speed Pro... I see the basic changing point for pump gas to race gas at about 13.0:1 with the proper tuning... So you'll be fine on 91-93.... It basically goes like this with CTR's being the highest OE piston... PCT (CTR) > P30 > PR3 > JDM ITR (P73-00) > USDM ITR (P73-A0) > and then P72-00 > and P72-A0 which i really wouldn't recommend... If you're building an LSVTEC there's no point in going that low... If you have a GSR head then you with either of those JDM GSR or USDM GSR pistons you'll only be in the low to mid 10's..... If i didn't cover anything go ahead and tell me... I don't even know what i just wrote.... hehehe

wm5holla

90-93 is super gas right? im still lost on this gas and piston thing means, but i will read it over !
if i had cr over 13 i have to use race gas?


[Modified by wm5holla, 6:09 AM 2/14/2003]

96-EJ6 B18C

check out c-speedracing.com/howto/compcalc/compcalc.php this is a compression ration calculator that will give you an idea what to expect. Good luck.

wm5holla

IT LOOKS like to me that he is sayin itr are for safe cars, and ctr are str8 up racers! but maybe im nuts?

EVOLMTR

I put a Ls/Vtec motor together for someone using CTR pistons. It was his daily driven car running pump gas. He has been driving it for months now with no problems.

ExospeedAMcrx

ok.. there are diff types of Import racing enthusiasts. theres teh guys who want a good motor that they can cruise around in.. and be fast... they arent gearheads... they dont really work on their cars and arent toying around the motor ever...

then theres the racers/gearheads.. they love to race.. take the motor to the limits. know their stuff and familiar with detonation, proper fuel usage, timing, etc.. this is who I will be more comfortable in having the CTR's in.

This is my point of view ok... If guy Type 1 asks me whats best for him... i wouldnt want him to have some high compression motor that he cant take care of. it would be safer to have ITR's in there for him.

wm5holla

i guess what i really need 2 know is, whats the differnt between ctr and itr... what mades itr safe?

Kataku2K3

The only difference is the ITR's will yield a slightly lower C/R making your car easier to tune and less prone to detonation... Peace

icelarry27

lower compression ratio, so you can still go with pump gas...i think CTR pistons hav like 12.5:1 which is a little shady...

wm5holla

define shady?

wm5holla

so ur sayin ctr are harder 2 tune? i thinkin of buyin a b18b block with ctr pistons installed!! so let me know thanxs!

1BlackHatch

CTR pistons increase compression due to their shape (higher dome) and therefore increase the chance of detonation. To reduce the chance of detonation you need to use higher octane fuel and more of it.

wm5holla

define..detonation

1BlackHatch

DETONATION


Definition: An unwanted explosion of the air/fuel mixture in the combustion chamber caused by excess heat and compression, advanced timing, or an overly lean mixture. Also referred to as "ping".



[Modified by 1BlackHatch, 4:38 PM 2/7/2003]

spettinger

to those who have built ls vtecs with ctr pistons and B16 heads, did the valve reliefs need to be cut any deeper? what cams were in the motor? it seems like the clearance would be really close.

GapxGuy

Why don't you just go with B16A pistons? They yield 11.5:1 CR with an unmilled B16 head.

wm5holla

and milling is??

GapxGuy

Milling is surfacing or sanding down the head to up the compression.

AzG35

PR3 (b16a) pistons work really well with decent CR (11.3:1). My friend did a really mild build with PR3's, B16a head, B18A block with GSR cams and put down 173 hp and 135 torque. Plus, you really don't have to worry about pinging with that CR as much as 12:1

Ek-CoolGuy

I have brand new OS PCT's. My head needs slight milling so if anyone wants to trade their new OS P30's hit me up.