pulsar pistons on a det?

[NeedCAforS13]

hey guys...i was looking up prices at the dealer on new pistons for my crap ones, and I can get the ca18de pulsar pistons (the 9.5:1 ones) new from nissan...what would the effect be of putting some 9.5:1 pistons in to replace my 8.5:1 current ones? They have some that are overbored slightly so I can clean up my block!

I talked to Paul and he said all i would have to do is keep the boost down, and power would come earlier too...and he seemed to think it would be ok.

would it be possible to get the high comp pistons (raise the compression) and a thick metal headgasket (lower the compression) and get it back to a more reasonable level, or is 9.5:1 reasonable for a turbo CA?

also would CA18ET pistons be ok? can I use my current rods and the et turbo pistons? what's the compression on those?

Thanks,Sean

[boost_boy]

Me personally, I wouldn't toy with such a sensitive issue (your engine). Either get you some good used pistons or order you some forged units. And that 9.5:1 must be from the later variants of the CA18DE because the 1988 models were 10.0:1. CA18ET pstons would not work because of the position of the valve reliefs.

[NeedCAforS13]

would the ca18de rings work on some used pistons? paul has some used ones, but i'm not sure how good they are... I guess i'll check them out too.

Sean

[McAdam]

uhm, the CA18ET pistons should be fine, if you can find them. they have 4 valve reliefs on them. do what I'm doing, get some CA20E pistons (dished, with 4 valve releifs) bore your motor, ceramic coat the pistons and have the sides moly coated, then cryogenically treat them. total would be like uhm, $30 a piston, new, $25 premium rings, $20 a piston, cryo treating $8 a piston, and my machinist will make up a set of "buttons" to use with the DE full floating pins for $40 a set, so total would be like under $300. check it out info on cryo treating

McAdam

[NeedCAforS13]

so are the et pistons good or not? i can get them new at the dealer (I work at Nissan and our parts guys said they can get them)

Sean

[elballoonrat]

hey sean, for $300 our machine shop can make custom pistons for you, 50 bucks more and they will ceramic coat them. you just have to meausre up the old pistons and give them the measurement(they can raise the compression for you if you want) or bring them a piston and they will manufacture brand new forged coppies, you can even have tephlon inserts installed so you can lower your oil pressure, which equals less resistance which equals power!! especially that high rpm stuff that you had mentioned to me aka 9000rpm goal.

for reference, my 4agze has 8.1:1, had i gone to 8.9:1 i would have seen roughly 10 more hp(8psi), thats on a 1.6L, so a jump up to the 9's should be very noticable.

[elballoonrat]

also, that site about ceramic coating, detonation is caused by hot spots, generally made by sharp edges in the engine cumbustion chamber, usually detonation is cause by the head, not the pistons. but...having higher compression pistons in their will cause a greater chance of detonation not only 'cause of higher compression but also because of the piston beiong domed(the point forms a hot spot) so if you run high compression AND you ceramic coat, you have a good chance of detonation. do ca's have knock sensors? maybe if you guy high compression buy 4 gm knock sensors(cheap) and tap them into your block at each piston location, then you'd have to connect them to your ecu some how, depends on how nice you block is. in mr2's high HIGH performance motors run 4 sensors because the sound doesn't travel well for some reason since ours is located at cylinder number 4 so number 1 sometimes knocks, ask some ca pro's about this. -Tim

[McAdam]

yes, I understand how detonation and hot spots work, but I am also having my combustion chambers, valve faces and exhaust ports coated as well. so that will eliminate pretty much all chances for detonation. or at least thats the plan. I dont think anyone has ever done al this ceramic/cryogenic treating to their engines before (or at least I've never heard anyone TALK about it) on a street machine. Should be interesting to see how it turns out!

McAdam

[CA19DET]

i have been thinking of getting my JE pistons ceramic coated coated to help with detonation and piston hot spots, pricing seems to be pretty good too..

[elballoonrat]

toyota pistons come ceramic coated stock! lucky me!

[Oneor1]

hey sean you should consider what elballoonrat said in a couple posts earlier...... sounds like a good idea to me

just throwin my 2 cents in