Combustion chamber changes

[rxkaffee]

Are any of you boosted guys using heads with modified combustion chambers? It looks like the quench area in these 3100 heads are fairly well designed.

I was wondering if there's any common anti-detonation or hotspot prevention in the chamber that you need to get ironed out.("ironed out" on an aluminum head, ha ha)

I guess this would be about the same for guys running super high compression on n/a, but I'm guessing there's not as many of them(since they have no subforum).

--rx

[rxkaffee]

Should I ask on an LS1 forum?

After looking at some pictures of 3400 and LS1 combustion chambers I noticed that they are fairly similar in design.

Heart chamber, big valve in left lobe, plug near the V of the heart, plug bung angled toward small valve, etc. etc. The big difference I noticed is the LS chamber does not form a full V opposite of the lobes, but cuts off short with a line straight across.
LS1

3400


They look similar enough that some of the LS1 builders might have some info on where the trouble spots are for borderline-knock conditions.

I'm only guessing that the gen3 3100 chambers (its a 3100 that I have to work with) are similar to these 3400's... please hop in and correct me if I'm wrong about that.

[MidnightriderZ24]

ive never ran into a big problem on my 3400. i ran 12 psi on stock bottom end and around 6200 i would feel knock retard. but with methanol injection i had no problem. as with any combustion chamber, eliminate any sharp edge!

[1988GTU]

This is a 60 degree forum, not 90 degree. You don't have much to worry about. Just don't go and run boost without an intercooler or blowing heat. Just like most applications, tune safe be safe.

[SappySE107]

We have good quench properties in the stock 3x00 motors so boosting has been pretty simple. Heart shape chamber helps too, but your pic is my modified street/strip 3400 head, not stock. Stock is heart shaped but shrouds the valves more than what you see, so flow isn't as good.