fst85vtt

Im in the middle of a heads/ cam/ clutch swap
and been buying parts as i can.. A buddy gave me a set of cnc ported patriot heads 241 castings with the double springs...

I noticed how large the intake runner is compard to the stock 241 head almost 1/4 bigger across.. also noticed that the section around the intake valve the little ramp as best i can describe is completly removed doesnt this induce the swirl and increase velocity? Iknow im going to have to get these flowed to see where im at.

Would i be better off just swapping the springs to a set of stock 243 heads

Bill Curlee

If there cnc ported patriot heads 241, there very good heads. I made 450 RWHP withe those a whiplash cam and ported Fast 90/90.

BC

AU N EGL

Springs would depend on the lift you are running.

anything under .600 does not really need double springs IIRC. and there really is no need to go over .600 or much over.

What intake and TB are you going to use?

BLOWNBLUEZ06

Swirl is for efficient burn while cruising (emissions) and does nothing for WOT performance but hurt it. If something that causes swirl is gone, GOOD!!!

dmiz0420

How does swirl hurt performance? Does it cause less air flow?

Swirl helps to mix the air and fuel giving a more homogenous mixture that leads to more consistent and thorough combustion. A more complete burning of the air and fuel would translate into more power which is evident in better fuel economy as less fuel is used to maintain the same speed at part throttle.

Why does this not prove true at WOT?

lucky131969

You meant to say " more consistent and thorough combustion"......right?

dmiz0420

right, thanks

any insight, just trying to understand... Dont mean to hijack... sort of did though... sry

fst85vtt

im using the ls6 intake unless the street warrior comes out before i get it together.
Cam is a 228/232 595/598 on 112 .
I know the heads make good power just didnt want to sacrifice driving manners my buddy had these on a 408 and made 460 to the tires

voda1

Find out the combustion chamber volume and the intake port volume. You need about 62cc chambers and 220cc or less intake port volume.

fst85vtt

Combustion Chamber: 67cc
Intake Runner: 220cc
Exhaust Runner: 67cc
Intake Valve: 2.02"
Exhaust Valve: 1.57"
Max. Valve Spring Lift: 0.650"
Spring Pressure Closed: 135 lbs. @ 1.800"
Spring Pressure Open: 375 lbs. @ 1.090"
Retainer Material: Titanium
Valve Seal Material: Viton
Valve Guide Material: Manganese Bronze
Valve Job: 5-angle

voda1

With 112-0 cam, .054 gasket, 67cc head: 7.8:1 DCR, 10.3:1 SCR

With 112-0 cam, .040 Cometic gasket, milled .035 to 62cc: 8.5:1 DCR, 11.3:1 SCR. With the oversize valves need to check piston to valve clearance.

Bill Curlee

Lucky131969 wrote me and asked if I had 241 or 243 heads. I have 243 heads. Sorry for the mistake. The 243 heads have 62 chambers thus better compression.

fst85vtt

well damn i just had my heads checked and now i know why my buddies car cracked the block with these heads .. i noticed that all the intake runners were dark had residue on them from combustion all except 2 ports.. The two ports looked amazingly clean ,
I knew in the back of my mind what that meant lol...
I had them pressure checked and walla when they were ported it got into the water passage , you can see 2 small holes.. The head guy says no big deal he can epoxy them ?? Well now im thinking it may not be worth the headache Any opinions If I may add these heads were only on the other car for an hour or so and it blew up on the 3rd dyno pull cracking the block

Bill Curlee

Well,,unless you can afford a cracked block (due to hydro locking) Ide pass on the head repair. Save your time and cash and invest in a new set of heads. (now i see why, porting can lead to a set of EXPENSIVE paper weights.

Bil

AU N EGL

an LS1 block can not take as much HP as an LS6 block.

LS6 blocks have much better cooling and oiling gallies around #7 and #8 cylinders. LS2s blocks even better. LS3s run too hot for some reason

and LS1 blocks go it usually around #7 do to excessive heat and poor cooling. LS6 blocks go in this area too.

Or the LS1 heads ( 241 ) go again poor oiling on the #7 and #8


Is there an easy fix? No, but running a bigger 4 core radiator helps the coolant. Use mostly water, 10% dex and two bottles of water wetter keeps coolent temps down.

I agree with Bill never repair a cracked block or head. Replace them.

BLOWNBLUEZ06

Sure the idea is to mix the fuel, fill the cylinders completely and control the flame propagation, but consider the idea that efficiency has a curve. What serves low velocity air flow doesn't necessarily serve high velocity air flow. Auto manufactures have to satisfy not only their consumers on a large scale, but the EPA and other government agencies. What you end up with is a "homogenous mixture" of engineering to satisfy all parties involved.

Swirl is for lower volumes of air. You can only have and control swirl up to a certain air speed. After that, it becomes another name called turbulence. At very low speeds the flow is laminar, i.e., the flow is smooth (though it may involve vortices on a large scale). As the speed increases, at some point the transition is made to turbulent flow. In turbulent flow, unsteady vortices appear on many scales and interact with each other. Turbulence causes the opposition to air flow. Take any high volume, properly ported cylinder head and see if that bump is still in there.
There are a few things that affect the efficiency of the engines allowing for good performance in tandem with fuel economy with that swirl bump only being one small item and again IMO is only for better efficiency in idle to low throttle conditions.

This is one of the things I learned from a highly respected man in this industry, Erik Koenig. I'm not that smart, but smart enough to shut up and listen when he speaks.

AU N EGL

good info

Bigger does not always mean more HP or TQ for heads and cams

lucky131969

Wow, someone better tell all these vendors building 10 second C5's with LS1's about this issue

AU N EGL

yup, the LS1tech.com guys call LS6 blocks LS1s any way, Call LQ9 iron blocks call them LS1 blocks too.

When they really look at their alumium blocks, these blocks are LS6s they call them LS1s

dmiz0420

I have no idea at what cfm the airflow becomes turbulent in whatever sized port, but that would be great info. I see what your saying about the stock head port is designed to induce swirl at a certain, lower velocity of air which inhibits performance at wot.

Given that heads are designed to operate at certain velocities which yield greater or lesser power & efficiency depending on the target range of RMP which the engine makes power, if swirl is designed to be induced at a high velocity, via the port shape or features on the port surface, could it be advantageous even at high velocities?

Sort of a rethorical question, I'm not trying to question what your saying or certainly what your expert is saying. Maybe Mr. T. Mamo can weigh in.

Sorry again for the hijack, hope it helps with the head decision.

I think it's hard to go wrong with LS6 heads unless your talking AFR 205 or TF territory. From what I remember the early ported 241's had a 235+ cc runner and the sock 243 has a 215cc runner. I'd bet the smaller runner is going to have better over all power band with the larger 241 runner having more top end. Check with patriot to see what the 241 runner volume was to make sure. Weigh your decision accordingly.