Help me get the best HP out of an N/A engine!

[HOYS]

Hey everyone, I'm looking to get the most HP possible out of a 3.4L N/A.

I'm starting from the ground up with this and open to any and all suggestions.

Price at the moment is not the biggest factor for me, as I will be building this over a year or so. (I don't just jump into things without thinking them through!)

I have a block that is ready to go. I'm looking at an over bore and using higher comp. pistons.

What do you all recommend for a high HP N/A engine? Specific comp. ratio for the pistons? I'm trying to get as much info here to make the best decision on what to buy.

Thanks a bunch and I hope to come out of this endeavor with a damn fine N/A engine. Who needs turbo lag anyway?

[Superdave]

which 3.4?


Also, do you want to be able to drive this thing daily?

[HOYS]

Sorry, its a LA1.

Driving daily is a must. I'm not looking at building a drag car, but anything past bat sh*t insane works for me.

[Superdave]

well, all the general rules of engine performance apply... more air in and more air out = more power

If money isn't an issue then i'd pick up a ported 3500 top end from wot-tech and also a street/strip cam, 65mm TB and find a set of headers. With a good tune you'll have a pretty healthy monster.

[HOYS]

I've read a good bit about the top swaps. Can I keep the 3.4 UIM? I hate the look of the 3.5.

[Superdave]

Yep, but you'll sacrifice a little power and the ability to grill burgers and hotdogs.

[HOYS]

Yep, but you'll sacrifice a little power and the ability to grill burgers and hotdogs.

Dang. If I get a ported 3.4 LIM, can I achieve the same goal?

What is everyones thoughts on pistons? The only higher comp pistons I can find are the forged pistons from wot tech.

[Superdave]

you could use the pistons from a camaro 3.4, They would work pretty well with the 3500 stuff (About 11.5:1).

[mfuller]

you could use the pistons from a camaro 3.4, They would work pretty well with the 3500 stuff (About 11.5:1).

Won't he be sacrificing some power because of the larger quench distance? Tech article sez that combo makes for .070" quench, and ideal is .040".....

http://wot-tech.com/shop/articles/pistons-and-quench/cat_76.html

[Superdave]

Quench is important but it's not the end-all to performance, i've got .050" and certainly not hurting for power. It's just another factor you take into account for when building an engine. Having a little extra room for rod stretch is never a bad thing when the max RPM's will be hitting the limits of the rods.

[mfuller]

Here's a neat little explanation I found on LS1Tech (was copied from another site), which gives some nice info on why you want a tight quench distance:

The general feeling is that the total quench or squish distance should be about .040". The quench distance is the compressed thickness of the head gasket plus the deck clearance. The quench area is the flat part of the piston that would contact a similar part of the head if you had .000 assembled quench height. In a running engine, the .040 quench height decreases to a close collision between the piston and the cylinder head. The shock wave from the near collision drives air at high velocity through the combustion chamber. This movement tends to cool hot spots, averages the chamber temperature, reduces detonation and increases power. The shock wave also provides better fuel/air mixing, and this allows the fuel to ignite better and burn faster. A faster burning fuel charge means less timing is required for optimum power output.

I suppose the OP needs to consider how fast he'll be spinning the engine....don't you rev to over 7 grand Dave? In which case, .050" is probably good to have as a safety margin against high-rpm conrod stretch, But if we're only talking 6000RPM here......

[bszopi]

http://www.theoldone.com/archive/quench-area.htm

That's where it was copied from... I was going there to see what they had to say about it, and post it, but...

[geldartb]

given that i plan to finally use the camaro pistons i bought awhile back this winter.

are all camaro head gaskets .050 and is there one brand that is better than the other.

[geoffinbc]

Good quench is key not only for power but for economy and detonation control. It is not a hard feat to achieve good quench. If you want to use Camaro pistons then go for it. Just have the deck milled to bring the quench to .040. If you follow the engine master challenge at all you will see that they all fine tune quench to get it bang on. Ones with good quench and modern herat shaped chambers barely run 30* of ignition timing (one I recall only required 26* for max power) and when they are disassembled for inspection the tops of the pistons have NO black on them. They look like the engine has never been run.

Another thing which is free and you might want to look into is dimpling the pistons and combustion chamber. It is kind of a new concept but I saw it performed on an Olds engine and it help homogenize the mixture and speed combustion. On a 400 CI Olds it was worth more than 20hp. I have never tried it but my next engine will have it.

If you going to spend the cash on the ported heads then it is a worth while investment. If you don't want to spring for it then just be damn sure you gasket match the port entries and clean up the valve bowls. Gasket matching the intake is also a must.

The valvetrain is easily upgraded and I think the stock cam is the first place to start. The cam can be bought or the stocker can be reground. Both are good options. Springs will be a must if you change the cam.

[robertisaar]

i wouldn't want a reground hollow-core if i was going to go through all this work.... just my 2 cents.

this dimpling does sound interesting though.

EDIT: thought about it more: that would actually increase the surface area of the piston AND drop wegith(slight, but still), which i imagine would help with quite a few things.