Maybe I should've done more research before I bought the 4AGZE pistons and rods. But just did some anyways, I have the 8.9:1 C/R 4AGZE pistons. I don't think I would've benefited much from any more research than I had before I had purchased them.
They will be going into a 4AGE ST Turbo set up.
Are there any + or - between the 8.0:1 and 8.9:1 4AGZE pistons in regards to a 4AGE Turbo set up? Been trying to find the answer by searching but found nothing where I'm lead to believe they're quite the same/ good. Both are forged and ceramic coated... The cuts are different...
(Not mine, the ones I have looks oil burnt dirty used) Wonder if the 8.9 and 8.0 is mixed up... This pic is from rollaclub.com
Need to find a shop in MD to get the pistons flycut for that 5th valve. If anyone knows a very good reputable, affordable place in MD/DC/N. VA... I think I may have one in mind.
I would assume so, the sluggish with the 8.0:1 C/R.
Have been doing some more thinking. A drop from a 10.5:1 C/R to 8.9:1 C/R is good enough having read up and saw pictures of 4AGE 20V BT and ST with stock internals that have been turbo'd or supercharged.
If anyone knows, by milling the piston for the 5th valve groove, for it being a ceramic coated top, does that affect anything?
the piston doesn't need to be cut. helped a friend build a 4agte blacktop with 8:9 4agze pistons, car has been running fine for over 2 years daily driving at 13 psi. Most of the guys from new zealand who build the 4agte 20v regularly say the often don't cut the pistons.
My guess is the place where you make the cut wont have the ceramic coating anymore, doubt it will affect the car though. Another thing, the silver top has a smaller combustion chamber than the 4age 16v 34.5 vs 36.5 cc, so the compression ratio will be a lil higher than 8:9 with a stock silvertop head and gasket. Probably around 9:0 to 9:1 roughly, still pretty good compression ratio.
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yeah, you'll be fine without cutting it. the only thing that could happen is it might cause it to be an interference engine. but because of the lower compression ratio, you might still be non-interference.
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(Not mine, the ones I have looks oil burnt dirty used) Wonder if the 8.9 and 8.0 is mixed up... This pic is from rollaclub.com
I believe those pistons are incorrectly identified.
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Modification: Changing something to what you thought it should have been from the start!
I'm sure they'll go in and work fine without the 5th valve milling. I just want to keep it as an non-interference motor just incase the belt snaps from age or whatever reason. Last thing I would need is a bent valve and more.
I figured the diagram was incorrect. I have the left one, so maybe I do have 8.0:1 pistons.
left one does look like the lower comp one because that looks like a dish to me
if you are boosting the 8:1's advantage is the increase in volume(which is what you want for boost) plus you definitely shouldn't have to mod fly cuts for 20v since it should have more than plenty of clearance
you don't need domed with boost because you have the turbo/blower doing the compressing for you, so you should go towards volume
but yes it will be weak ass if you're off boost, if you go with the right turbo though you should be on boost almost always in your desired rev range
so i vote for the dished piston on the left, and i think it is listed wrong or backwards
if you are still worried about the valve to piston clearance with the dished pistons, clay it and if you aren't happy with the clearance or lack of then get a thick hg
Last edited by canadianae92; 06-07-2010 at 02:08 PM.
Enough clearance when the timing belt snaps? That's the only concern.
I have the dished one
might be best to see if there is clearance at full lift while at tdc or how much, the deciding factor could end up being head gasket thickness but i think if you are using stock cams at least on a 16v you will be non interference idk about 20v though
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8.0:1 or 8.9:1 C/R, Any Better Than The Other?
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