What compression ratio pistons for new engine?

[rmcdaniels]

Probably getting an engine built, B18C1 short block with B16A2 head, JRSC,10 lbs. boost, Hondata, 440 injectors, Aquamist water/methanol, other miscellaneous goodies. What compression ratio pistons should I use and why?

[HONDA GHANDI]

If you dont have plans to up the boost I would go with no less than the stock 10:1. It has been proven that you can make safe power with them. And with Hondata on board you can tune it correctly. If you are good at keeping your methanol tank full you can even go higher. Id plan on a blockgaurd and rods though while you are in there.

[rmcdaniels]

10 lbs.is about it for my JRSC setup. I was going to do the rods (Crowers), but I'll check on the block gaurd. With a .5mm jet, my tank easily lasts a week or more and I check it when I fill the gas tank, so I shouldn't run out. I'm going to put either a float switch or a pressure switch on it so I get a warning if it does run out. What about pistons?

[HONDA GHANDI]

what do you mean? Brand? or CR?

[rmcdaniels]

Should have been clearer, brand. I've had JE pistons recommended, also Wiseco, but also heard bad things about wiseco.

[HONDA GHANDI]

In order of quality: CP, Weisco, Ross, JE, Araias.

[rmcdaniels]

I think that about covers it, thanks for the help.

[rmcdaniels]

One other thing, a brand recommendation on the block guard?

[HONDA GHANDI]

STR, or newformz

[hsunchen]

In order of quality: CP, Weisco, Ross, JE, Araias.

I know this is an ancient thread, but did you mean CP is the worst or the best???

[HONDA GHANDI]

CP being the bestest.

[ryanman]

bestest



LMAO

[HONDA GHANDI]

Ooops, I mean bestester.

[hsunchen]

bestest


No; Ryanman's avatar is the bestest.

[rmcdaniels]

No; Ryanman's avatar is the bestest.

My daughter liked his old one better. She was fascinated by it. Every time she walked by and I was on HAI she would look for it and start asking questions. "Daddy, what's that man doing? Why is he doing that? Can I see that man doing that thing again? Who is that man? Is he your friend?" She's almost four.

[rmcdaniels]

CP being the bestest.

The guy who built my engine said something about forged pistons causing excessive wear, depending on what alloy was used. I ended up with the Wiseco's because he said that they had a model that gave oem-like longevity, but that they were not the best for making the most power. What's your take on that? I'd hate to have to rebuild my engine every year or two.

[JKOBDHARNESS]

I would be a little weary to run that blower with 10:1 compression without some serious tuning. That blower creates so much heat past 8psi. I ran into detonation around 10psi when I had my ef with the JR and it was at 9:1 compression. What engine management did you end up with?

[ryanman]

I would be a little weary to run that blower with 10:1 compression without some serious tuning. That blower creates so much heat past 8psi. I ran into detonation around 10psi when I had my ef with the JR and it was at 9:1 compression. What engine management did you end up with?
Remeber we're also at wayyy higher altitude then you are in florida. We can run a little more boost up here then at sea level.

[HONDA GHANDI]

Mine runs at 10psi here and 11 down at sea level. No knock at either altitude and the highest intake temp I have seen is 160 degrees (still too hot IMO) on a 95 degree california day. but normally its in the 140 range. Hondata tuned.

[rmcdaniels]

I would be a little weary to run that blower with 10:1 compression without some serious tuning. That blower creates so much heat past 8psi. I ran into detonation around 10psi when I had my ef with the JR and it was at 9:1 compression. What engine management did you end up with?

Hondata with serious tuning. The guy who built the engine ended up putting in 8.4:1 pistons by mistake and I didn't feel like hauling it out for a rebuild, so the JRSC is on ebay and the new turbo should be on in a few days.

[rmcdaniels]

Mine runs at 10psi here and 11 down at sea level. No knock at either altitude and the highest intake temp I have seen is 160 degrees (still too hot IMO) on a 95 degree california day. but normally its in the 140 range. Hondata tuned.

My IAT sensor reported around 140 degrees, but when I put a calibrated bead-wire sensor attached to a good meter in the output air flow from the SC I found out that the air was actually at 200+ degrees at 10 lbs of boost. I think the IAT doesn't read the real temp, maybe due to its location out of the air flow.

[exciv2000]

I think the IAT doesn't read the real temp, maybe due to its location out of the air flow.

Exactly. Even more so if your IAT sensor is stuck somewhere along the intake pipe tract vs. stuck in the back of the JR intake manifold.

[rmcdaniels]

Exactly. Even more so if your IAT sensor is stuck somewhere along the intake pipe tract vs. stuck in the back of the JR intake manifold.

Sure for a JR setup, but for my turbo setup I was going to put it back in front of the TB. I think that should work well, although I see a flat spot on the casting of my stock intake manifole that looks like it's the right size for a '95 style IAT. It looks like I could drill three holes, tap a couple of them , and have an IAT sticking right down into one intake runner. Not sure what that would do for air flow, but it might actually provide an accurate reading.

Of course I think it's moot if I'm getting my fuel maps set manually with my car on a dyno with a wideband in the tailpipe. I think then that putting the IAT in front of the TB will give a good relative measure of the temp that should serve well.

[exciv2000]

for turbo, IAT before TB should be fine. For JRSC, I'd highly suggest putting the IAT aft of the TB, like in the JR IM on the flat spot.

[rmcdaniels]

That's how I did mine with my JRSC when I got my Hondata system. It was in the JRSC instructions on the Hondata Web site.

[HONDA GHANDI]

anywhere in the charge pipe after the intercooler will be fine on your new setup.
I measured my intake temps with the datalog and a temp sensor probe and they were within 5 degrees of each other on my SC setup. Never got close to 200.