What you think about these babies??? 12.3-1 CR
Now I will smoke Slowerthanu by even more!!! j/k

Guess what brand these are? They are the Cosworth built JUN pistons!


82 mm of untapped power/love!

These pistons are going into the infamous #31 from the Type R Expo!

See you guys at the next EXPO!

 

damn your car is tiiite!!

 

Hope you're going to smooth out those sharp edges on the domes...

 

If you do that you'll get 12.0:1 cr

 

OOOOOOOOOOOOO ohhhhhhhhhhhhh aaaaaaaaaaaaaaaah
shiny, go-fast parts!!!!! yummers!
hey, at least slowerthanu will be able to keep up with you in and outta the corners when he receives my GSR seats...

 

Schweet Pistons .!!!!!!!!! ..But you must have paid an ARM,LEG and Left NUT for them... Also your your car is ging to Rip with the 1840ish cc's..TORQUE

 

The better to beat me with! It is ok, we were all kidding. When he posted that I was sitting next to him fondling the piston's. The sharp edges on the center of the piston are not as important as the edge's on the outside of the piston. ITR 1236 has not made any final decision's on what all he is going to do during assembly. All he knows is he wishes they were in write now.

 

hey, those pistons l00k sweeeeeet
if possible, could you take some more pix, especially of the ring lands. It's kinda hard to tell b/c they're out of focus.
thanks

 

Do not smooth the edges. Leave the design alone. Cossworth did it that way for a reason. Someone is obviously a Larry-head.

 

Damn, Slowerthanu, you have some friends with some nice *** cars. That Type-R looks sweet. Sorry about your knee too, I did end up going to the Auto-X and ran. I did better than a WRX! Haha, but not too well at least I think. It was cool though, met a lot of people there, but I just wonder how bad it is gonna be on my car....oh well, I'll be there on the 24th at the next event at the E-Center. Excited too because I just got my ITR Swaybar

 

Dan,

No offense but I'll assume that JUN spec'd the piston design and not Cosworth. They were probably left that way due to a higher profit margin that could be realized. My gutt tells me flame propagation would be enhance if the flame had to travel over smooth edges versus sharp. Most things flow better when the path is smooth, or else people would build headers with mitered angled joints instead of mandrel bends. Why don't head porters leave the combustion chambers stock with edges?

I know from burning some JE pistons in my GT4 engine that sharp edges can be prone to detonation initiation points. To make the most power you have to run the engine on the edge and whenever you can move that edge farther away there's room for improvement.

Take for instance camshafts, why are Toda Bs more expensive than As and Cs more expensive than Bs? Because people are willing to pay more to make more power. While in real life the Cs are the cheapest to make. Why? Because whoever machines the cams for Toda (I don't know maybe Toda does it themselves) they probably start with the same billet for all 3 versions since it's probably the cheapest way for them to purchase in quantity. So to machine the A's (less lift and duration) more CNC time is needed to remove more material. But the least amount of time is needed to machine the Cs since those lobes are the largest, but we pay the most for them. Ouch! don't squeeze too hard.

They (JUN) could have saved more money if they didn't machine those damn arrows in the top surface.


[Modified by SMSP, 2:14 AM 8/22/2001]

 

Well said SMSP. A lot of folks really think that manufacturers make their product in a "certain" way because they are beneficial to their purpose... yeah right, at least not in money-hogging JDM parts. Money comes first, and then customer appeal, which sharp edges and mirror-like finish really does the job. You know, there are actually head porters out there who polish and buff cylinder heads to a mirror-like shine (that "looks" good) for a living




[Modified by Tony the Tiger, 6:33 AM 8/22/2001]

 

...first time I've seen a real bone-head from Dan... the average mind should be able to see why smoothing the piston dome's edges would work... remove the minumum amount of material needed to smooth the edges though...

 

CONGRATULATIONS! I know you have wanted these for a very long time now Jon. I know that you got them just so that you can say that you have higher compression then me. The car is coming along well. Maybe you will be able to show up the TODA equipped ITR's at the next EXPO! And dont forget to thank your DAD! LOL j/k

 

what is kinda messed up about toda cam pricing is that in japan all 3 profiles retails for the same. why the different pricingin north america. because there are plenty of people here who are easily mislead.

 

I'm not sure what to do about the edges. I would be afraid to mess something up. They weren't exaclty the cheapest pistons, but I will probably call JUN and see what they have to say.

 

Hint: study the theory of cooler plugs/why they are needed and apply it to your application...

However, if your not comfortable doing that kind of work, then your not... probably good for some noticible hp though...

 

I have read about sanding the edges of pistons to reduce the chance of detonation since reading Hot Rod magazine in middle school. Jun left the extra material so the customer could make the final modifacations needed for there specific application.