[joe_bocc]

I agree with that. 4032 is great for street motors and just about any all motor build. The tighter clearances should pay off with better longevity of the piston itself and the rings (they're less exposed). The Mahle pistons are 4032, have coated skirts, and generally one of the best off the shelf 4032 piston makers out there. That's what I would use if I was going to start a new build today.

2618 can take more abuse b/c it has a higher tensile strength. That means when high HP starts pounding the piston, high revs start to stretch the piston, and high heat starts to soften the piston, 2618 has a greater ability to take the load without falling apart in a catastrophic manner. The downside is that the coefficient of thermal expansion is greater meaning you have less consistent skirt profile as temperature varies. This makes it a little bit more tricky to get daily drivable longevity out of a 2618 piston versus a 4032 piston.

You and CChang5 make good points. Since I have no plans of boost I should be fine with the 4032 pistons. Could they hold up to stress of road racing? What about nitrous? I'm not decided yet but I'm not ruling out throwing my Zex wet kit with a 50 shot in the car if I'm gonna drag race. Since "weaker" OEM cast pistons can handle moderate nitrous and aren't a major no-no with racing, I don't see why I would be assembling a "ticking time bomb".

I was looking at the Mahle pistons but they only seem to make RSX 86mm pistons. They MAY make 87mm piston, but I can't find them on the internet. Maybe I'll get in touch with their customer service.

Anyone have any experience with the Supertech pistons? They make the 4032 pistons with a 87mm bore and a 12.5:1 c/r. Thay also come with a "'phosphate dry lubricant’ coating to protect the rings against ‘micro-welding’ and enhance lubrication on the skirt/cylinder area."

 

[joe_bocc]

and when you talk about the clearances are you guys referring to the piston rings?...

just tryin to get a better understanding

I'm pretty sure they're referring to piston skirt to cylinder wall clearences. Less piston expansion from heat means they could run tighter clearences.

The way I see it, 4032 pistons bridge the gap between OEM cast pistons and 2618 forged pistons in regards to strengh and reliability.

 

[K20SIRCOUPE]

Ok I keep seeing this claying stuff, but how do you put the cam gear at specific degree to test clearance to see how far it can go before it has problems?

 

[chunky`]

You and CChang5 make good points. Since I have no plans of boost I should be fine with the 4032 pistons. Could they hold up to stress of road racing? What about nitrous? I'm not decided yet but I'm not ruling out throwing my Zex wet kit with a 50 shot in the car if I'm gonna drag race. Since "weaker" OEM cast pistons can handle moderate nitrous and aren't a major no-no with racing, I don't see why I would be assembling a "ticking time bomb".

I was looking at the Mahle pistons but they only seem to make RSX 86mm pistons. They MAY make 87mm piston, but I can't find them on the internet. Maybe I'll get in touch with their customer service.

Anyone have any experience with the Supertech pistons? They make the 4032 pistons with a 87mm bore and a 12.5:1 c/r. Thay also come with a "'phosphate dry lubricant’ coating to protect the rings against ‘micro-welding’ and enhance lubrication on the skirt/cylinder area."

You could definitely do nitrous on a 4032 piston. I wouldn't do a large shot, but 50 shot should be fine.

Mahle does make an 87mm piston. Check their website for a part #, I looked it up not too long ago.

I'm about to give the supertech pistons a whirl. I'll let you know how they run in a few months once i get some miles on the motor. The main caution with them is that the spec sheet has a clearance recommendation that is way too loose IMO. I have a lot of discussion on that in my latest engine rebuild thread, search for it.

 

[K-serious]

You could definitely do nitrous on a 4032 piston. I wouldn't do a large shot, but 50 shot should be fine.

Mahle does make an 87mm piston. Check their website for a part #, I looked it up not too long ago.

I'm about to give the supertech pistons a whirl. I'll let you know how they run in a few months once i get some miles on the motor. The main caution with them is that the spec sheet has a clearance recommendation that is way too loose IMO. I have a lot of discussion on that in my latest engine rebuild thread, search for it.

Would you recomend 2618 for a big shot of nitrous?

 

[joe_bocc]

You could definitely do nitrous on a 4032 piston. I wouldn't do a large shot, but 50 shot should be fine.

Mahle does make an 87mm piston. Check their website for a part #, I looked it up not too long ago.

I'm about to give the supertech pistons a whirl. I'll let you know how they run in a few months once i get some miles on the motor. The main caution with them is that the spec sheet has a clearance recommendation that is way too loose IMO. I have a lot of discussion on that in my latest engine rebuild thread, search for it.

I looked it up and they do have one 87mm piston meant for the RSX. Its a 12.7:1 c/r with RSX so that like 13.2:1 with K24 block and K20A2 head? Too high for 94 octane?

I'm really interested to see how the supertechs work out for you. I haven't seen anyone running them. You running the 12.5:1? If you remember, let me know. I'll check out your thread for sure!

 

[joe_bocc]

Would you recomend 2618 for a big shot of nitrous?

How big of a shot are you talking?

Although Supertech claims their pistons can handle 42 psi of boost and are built to handle nitrous without giving any type of limit, running 2618 CP, JE or Wiseco pistons wouldn't be a bad idea.

 

[joe_bocc]

Ok I keep seeing this claying stuff, but how do you put the cam gear at specific degree to test clearance to see how far it can go before it has problems?

I wonder this myself but haven't really looked into it. I assume there's some way to manually set the timing for testing.

 

[chunky`]

I looked it up and they do have one 87mm piston meant for the RSX. Its a 12.7:1 c/r with RSX so that like 13.2:1 with K24 block and K20A2 head? Too high for 94 octane?

I'm really interested to see how the supertechs work out for you. I haven't seen anyone running them. You running the 12.5:1? If you remember, let me know. I'll check out your thread for sure!

The compression ratio will be higher, but you can always remove some material on the piston or use a thicker head gasket.

Yes, I'm running the 87mm 12.5:1 supertech pistons.

 

[K-serious]

How big of a shot are you talking?

Although Supertech claims their pistons can handle 42 psi of boost and are built to handle nitrous without giving any type of limit, running 2618 CP, JE or Wiseco pistons wouldn't be a bad idea.

Like a 150 shot, also what would be a good CR for this?

 

[RedEG]

Good ideas, keepn it N/A. I have a N/A k20/24 250whp daily drive/track set-up with inlinepro k24 block (je piston 89,) k20a2 head (ips k2 cams, w/Eibach EVsprings kit with Ti retainers, oem valves), RBC intake, Hytech exhaust, Kpro, RDX 410cc injectors, removed a/c, p/s. It's lots of fun.
Note tuning is import I had a B turner try his hand at my K not a good idea.
Had to be returned and it cost me again.

 

[joe_bocc]

Read your build thread. Lots of good info. Sucks to hear about the motor going like that but the new one sounds like it'll really perform. Alot like I'm planning but with the 2.4L block.

I was gonna run my built K24 block with the stock head while I sourced the valvetrain but your thread made me realize the lack of overlap with the RSX-S cams would mean an even higher dynamic c/r.

The compression ratio will be higher, but you can always remove some material on the piston or use a thicker head gasket.

Yes, I'm running the 87mm 12.5:1 supertech pistons.

Is there a rule-of-thumb for converting c/r in K20's to K24's with the same pistons?

Since my BDC volume is ~13% larger, do I assume my c/r is 13% higher? So that would mean 14.3:1?

 

[joe_bocc]

Good ideas, keepn it N/A. I have a N/A k20/24 250whp daily drive/track set-up with inlinepro k24 block (je piston 89,) k20a2 head (ips k2 cams, w/Eibach EVsprings kit with Ti retainers, oem valves), RBC intake, Hytech exhaust, Kpro, RDX 410cc injectors, removed a/c, p/s. It's lots of fun.
Note tuning is import I had a B turner try his hand at my K not a good idea.
Had to be returned and it cost me again.

Nice, well rounded set-up. You have a sleeved block? What c/r are you running?

Tuning is a bit of a concern for me. I don't know of any Kpro tuners around here.

 

[mauiboi]

red eg what cr your running?