3.2 liter high compression pistons

while somewhat of a cross-post, here are what the JE 10.5:1 and stock US 9.2:1 static compression ratio pistons look like. There were off an existing Norwood pattern and designed after the combustion chamber was cc'd. This car has a requirement to run on street premium, so it was felt about 10.5:1 was about as high to go with some safety margin with the ported heads. I've never done this before, but I understand that raising the compression ratio really makes a noticible difference in seat of the pants driving. We'll also probably start tuning at a reduced advance of 30 degrees btdc and slowly advance for safety regarding detonation.
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login

 

Pretty!

 

Russ,

Superchargers, Modified Heads, High Compression Pistons ?? When will it end!!


You guys are killing me! LOL!

 

Chris
supercharge? not me - it's like dynanite fishing.

 

Russ,

With all these different mods out there for our Fcars, i'm going to be in the poor house soon. LOL

I have to start limiting myself to this site soon.

 

Gotta love those forged pistons! I'm excited to see the horsepower and throttle response changes. Going from 9.2:1 to 10.5:1 pistons is really going to sharpen your throttle response. I'm going to guess that your 1 point increase in compression 9actually 1.3 points) is going to net about 10% increase in power, all other things being equal.

Keep us posted!

Bob

 

Yes, when will it end????

Hopefully never

 

They're pretty, but you're going the wrong way with the compression man....tha't will really limit the amount of boost you can run. I think I'm going to drop to 8:1 and try to get the boost north of 20

 

Mark- You have Motec and 4 valve heads, don't drop the compression. With the right maps and good air temps you should be able to run 9.0-9.5 at 18psi on good 93 with the right parts in the motor. If you go to a 93/106 mix or a straight 106+ go to 27 and make some big numbers. Even with your blower set up the drop in compression will lose area under the curve till she is flowing some air.

 

James,
With the stock pistons (factory claims 8.6) and 93 octane pump gas I was running 18 psi at 7000rpm that climbed to about 22 psi and it did seem fine. I think with the heads flowing better now the peak hp will be at about 7700-8000 so I shouldn't have to deal with the boost rising at the end so I could turn up the blower and get 22 across the board....at least in theory....

Anyway, I had it in my head that if 8.6 worked at 22 psi, then dropping down to about 8:1 would let me push the boost to 24-28 psi on 93 and make about 750 hp. The second part of the thought was to open up the LSA to 112-114 and possibly take a little duration or the cams (the heads flow so well now, particularly at low lift that thing the stock duration may make peak hp around 8200 on my little 3.0 liter....and I'm not sure I want to run that high) and I should be able to maintain low rpm cylinder pressure at the expense of a bit of peak hp, which could be made up with boost...again at least in theory.

I'd sure like more compression if I can get away with it....I'm just starting to get a bit scared. I'm not ready to order the pistons just yet.....still working on the patio from h*ll that is eating more than all my money, but I will most likely call you when I am ready.....I would like more compression.....

 

It is hard for me to deny the power from forced induction, but I still prefer going natural...

So, how much is a guy looking at spending to get this done? I'm about 6 months from engine out so that would be the time.

Gene

 

Everything is a bit variable with regard to how much I did and labor costs, so it is difficult to nail down exact labor price. Partswise, the pistons I believe were $1349.81 and wrist pins $112.38. I think one of the best bets would be to get the heads done, which is about $2 - 4K depending plus assembly.

Here is an interesting reponse from the other board from Chris Fricke on increasing compression:

I am hoping for Chris' "much more lively" feeling engine with most of the improvement below 7K in throttle response and torque rather than chasing an ultimate peak number (although I plan to whoop up on Mark's NA number handily )

 

Looking good Russ! I'll be starting soon on another run of adjustable pullies, keep you posted.

although I have a 2V I have 9.5:1 forged pistons and 20psi of boost. timing is peaked at about 40*. at the end of the yr I'm gonna switch over to full EFI for more fun. the one thing with the forged pistons is the rattle when cold.

 

Russ, I have been planning on going to 10.5 on my 328 but was not "warm n fuzzy" on my conversations with Wiseco. Can you send me infor on your pistons, part# and a contact name.... I am assuming that other than the porting , all else is stock on the 328 motor....

 

Russ, when you say silly things like that, all your credibility goes right out the window....whoop on my NA number....man I need some of what you've been smokin









(Now I'm almost forced to listen to James and get the 9.5 pistons....and a 360 crank....and I don't know what all else but I just can't have you whoopin on me )

 

Isn't that blasphemy???? Welcome to the dark side

 

I am running borgo ho comp pistons in my 308 euro carby - great overall torque....

 

James Patterson (see his response below) at Norwood's (FChat sponsor) has an existing design at JE and I got them through him. The engine bottom end is stock. I'd give him a call if interested.
What did Wiesco say that was not warm and fuzzy? That is interesting: JE and Wiesco are owned by the same folks I am told.

 

Very cool (although my teenage daughter has informed me people do not say that things are 'cool' anymore). Do you recall the compression ratioo? Any other comments with regard to power curve and/or pinging/detonation? Everyone that I have spoken to says they make a very noticible difference.
Many thanks

 

You are soooooo very predictable....
Russ 'if someone has a button, I'm gonna press it' Turner

 

Vic (the guy doing Russ's and my heads) tells me he never uses Wisco if he has a choice. It's not that there is anything wrong with the pistons, it's that they screw-up the dome cc every time. It looks like they calculate the correct dome, but then cut .060 or something like that off the OD of the dome...so they end up about .5 point lower than you asked for....unless you re-work the head to make up for it or know to order .5 point more than you really want knowing they will be wrong when you get them. Strange.

The JE pistons on the other hand will be exactly what you asked for....which is why they are so popular with the top shops I guess. The JE pistons are also always about as light as they can be, there really is no extra metal if you change you mind on compression or valve pocket depth…they are as light as they can be. Other brands I've used have come with domes well over 1/2" thick because they only have 1 or 2 forgings, so flat top or 1/2 dome is the same part, it's just how much they cut off the top when they finish it (I don’t know if wisco falls into this group, the couple sets I’ve seem looked pretty good).

 

Oh I'm just funnin you.....I'm building a blower motor, so your flow restrictors....I mean webers are my only hope of beat you in the NA number

 

A) they could not look up pistons from an engine type---all custom pistons are simply given a code. Even with a name of someone that had purchased 10.3 328 pistons from them, no joy...
2) their piston is simply a flat top from what i saw from others, It would appear that you rJE was atleast given a little effort on the design.

 

WISECO 308 pistons... $1,080.oo USA

JE 308 Pistons... $ 1,392.oo USA


I believe that warm and fuzzy feeling is to be had from Wiseco, , , for $ 300.00 bones

 

interesting---a side note though---Wiseco also seemed to be very familiar with the 308 but could not find anything on the 328----

I would be happy to go with Wiseco IF they can get me what I need.. Hey and I also need 12 new 10.0 pistons for my 330 motor too...........


all help is appreciated