Chicago Crew UnderBoss

iTrader: (1)

I am going to have a forged 347cid, LS6 9:5 to 1 blower motor made for me in the near future. I will be running stock LS6 heads (64cc) and -11 reversed domed wiseco pistons to achieve this compression ratio, that will be seeing up to 14 lbs of boost via a D1SC blower.

What are your thoughts (good or bad) about this combination of using reversed dome wiseco piston (-11cc) and 64cc stock LS6 heads, to get compression down to 9:5 to 1, on a forged blown LS6 motor?

DAPSUPRSLO

iTrader: (14)

It's been indicate to me by sources in the know that pistons currently used in cup are not a reverse dome piston, but a full circular type dish at the moment. This source and I discussed some possibilities for that with the source indicating it was mainly for balancing reasons as full dish pistons with circular dishes don't have off balance weight distribution like a reverse dome piston can. One thing i've been considering on this subject is the possibility of opening a pathway for flame travel. The reason I think this may be of some significance is the recent grooving of the quench area of the head discussed in another thread returning some promising results. It seems as if the full dish piston and the groove sited above allows a path for the flame to act over the entire face, or atleast more of it then a reverse dome, when going off at top dead center. It would seem something with alot of quench/squish area would not allow near as much area of the piston to be acted upon during the travel of the flame front. This is all an educated guess ofcourse though. Bottom line is there's a reason that nascar doesn't seem to be using reverse dome, but full dish pistons in their motors, be it for weight distirbution, flame travel, or other reasons.

Chicago Crew UnderBoss

iTrader: (1)

"Bottom line is there's a reason that nascar doesn't seem to be using reverse dome, but full dish pistons in their motors, be it for weight distirbution, flame travel, or other reasons.[/QUOTE]

I agree with you that there certainly is a darn good reason why NASCAR uses full dish pistons in their high compression, very high revving, N/A racing motors, with a shelf live of 500 miles seeing 9000 rpm.

However, there is a huge difference however between a high compression N/A Nascar motor vs. a sig. lower compression motor making 14 lbs of boost via forced induction, be it a cent. supercharger, a turbo, a roots sytle blower, on a street driven corvette, etc.

DAPSUPRSLO

iTrader: (14)

I agree with you that there certainly is a darn good reason why NASCAR uses full dish pistons in their high compression, very high revving, N/A racing motors, with a shelf live of 500 miles seeing 9000 rpm.

However, there is a huge difference however between a high compression N/A Nascar motor vs. a sig. lower compression motor making 14 lbs of boost via forced induction, be it a cent. supercharger, a turbo, a roots sytle blower, on a street driven corvette, etc. [/QUOTE]

No doubt and a very good point. You'll notice weisco offers a turbo piston, which happened to make it's way in my n/a 11.5 to 1 c5r 434 (38cc dish in my case), with a full dish claimed to take 1250 hp for your turbo blower needs

Taspeed

iTrader: (1)

I'm not an engineer, but I always thought that a full dish piston and small combustion chamber is best on the street driven world because of the quench and a better burn. The dish piston forces the combustion to the center of the cylinder which helps to exhaust more gases from the cylinder. And something about creating the spherical swirl in the chamber. I would really assume that the shape of the combustion chamber would have a greater bearing on this also.

rich

DavidNJ

Great pictures and showing a lot of what we've been talking about.

Things I noticed: the chamber is welded up to place the plug decidely toward the exhaust valve; The reverse dome is deep over the exhaust, shallow over the intake; the edges of the reverse dome have been carefully radiused; the quench is so tight that the piston is kissing the head...at least it looks that way to me with matching marks on both.

From what I understand this is a setup designed for optimal combustion. With the top gas ports, it must be for drag racing or something similar.

Where do you buy it?

SStrokerAce

iTrader: (2)

Those are all photos of Kaase's Engine Masters setups.... both big blocks. Top is a Poncho, bottom a BBF.

I beleive the dish depth is equal all the way around too, it just looks like it's biased in those pictures.

Bret