LS vs old school Opinions

[O4L]

@swampratt does the fuel need heat or is that just the easiest way to improve atomization?

You know much more about all this than I do but heating the fuel just sounds contrary to most methods for the best performance. Would another way of atomization be a better solution or am I totally missing what the problem is?

 

[65ny]

For decades people have worked to get cooler and cooler intake charge temps because this obviously leads to more power but you want to heat up the intake?? I think you just need a good person to tune it. Do you own a wideband?

@swampratt does the fuel need heat or is that just the easiest way to improve atomization?

You know much more about all this than I do but heating the fuel just sounds contrary to most methods for the best performance. Would another way of atomization be a better solution or am I totally missing what the problem is?

Well.......there is a point where not enough intake heat will cause the fuel to NOT atomize and cause the fuel to condense on the manifold walls. When this happens, the fuel (the correct amount) doesn't make it's way into the engine. This is why you get bog and stumble. That's why carb'd engines run rough until they warm up. When the intake runners saturate they dump raw (again, not atomized) fuel into the cylinders which is obviously not ideal.
That's probably an oversimplified explanation; Swamprat can take it from here....

 

[swampratt]

You pretty much got it 65ny.

Some heat is needed or a choke.
He could run a closed air filter housing and make exhaust heat risers and get some heat into it..I have made a couple dual snorkel air filter housings with dual heat risers that were placed over headers.. It worked well and at Full throttle the heat risers were closed and fresh cool air came in.

The issue with too cold is that it is way way too cold. Pour gasoline or alcohol on your skin and it cools it.
Make the liquid 40 degrees and do that.
Now take an intake that is also 40 degrees or colder and add fuel to it.

Problems starts compounding.

Yes you can do it differently Remove the heads and make the intake runners much rougher. port the head in such a way to add a lot of swirl and turbulence.
I have no idea what kind of airspeed/ swirl or turbulence these LQ9 heads or any LS head has.

But too much air speed is not a good thing either. I do not think these heads have that issue.. I think maybe they are lazy down low for their volume and that is why I have not been impressed with the LS yet.
And why I had to go so rich to make this thing happy.

It may be one of those deals where we use different jetting in winter than in the summer.
Another issue is he wanted to run a 160 thermostat. I told him those engines like some heat.

But his deal and it just makes tuning it harder.
He was not even keen on trying a hotter thermostat just for grins.
OH well.

 

[doctorjj]

You pretty much got it 65ny.

Some heat is needed or a choke.
He could run a closed air filter housing and make exhaust heat risers and get some heat into it..I have made a couple dual snorkel air filter housings with dual heat risers that were placed over headers.. It worked well and at Full throttle the heat risers were closed and fresh cool air came in.

The issue with too cold is that it is way way too cold. Pour gasoline or alcohol on your skin and it cools it.
Make the liquid 40 degrees and do that.
Now take an intake that is also 40 degrees or colder and add fuel to it.

Problems starts compounding.

Yes you can do it differently Remove the heads and make the intake runners much rougher. port the head in such a way to add a lot of swirl and turbulence.
I have no idea what kind of airspeed/ swirl or turbulence these LQ9 heads or any LS head has.

But too much air speed is not a good thing either. I do not think these heads have that issue.. I think maybe they are lazy down low for their volume and that is why I have not been impressed with the LS yet.
And why I had to go so rich to make this thing happy.

It may be one of those deals where we use different jetting in winter than in the summer.
Another issue is he wanted to run a 160 thermostat. I told him those engines like some heat.

But his deal and it just makes tuning it harder.
He was not even keen on trying a hotter thermostat just for grins.
OH well.

Good info. Thanks.

 

[swampratt]

You can heat the fuel to a point but then it reaches boiling or a vapor point quite fast especially with ethanol in it.
I have actually had heat soak issues in some cars and I try to cool the fuel.
That would not be an issue if I ran a return type fuel system.

 

[Dave70968]

You can heat the fuel to a point but then it reaches boiling or a vapor point quite fast especially with ethanol in it.
I have actually had heat soak issues in some cars and I try to cool the fuel.
That would not be an issue if I ran a return type fuel system.

"Return-type fuel system?" As in, the pump provides more fuel than the engine needs, and the excess is returned to the tank? If so, that's common on some airplanes...and an easy way to empty the tanks if fuel isn't returned to the same tank from which it is drawn (I've flown one configured that way).

 

[swampratt]

yes.