Orr89rocz

iTrader: (13)

Now part of that might be lack of availability in iron tho. Aluminum is lighter anf easier to machine and port. And its lighter. Hence why alot of iron heads are being phased out, even in sbc world. Only ppl who run iron seem to be in classes that specify iron only.

There arent many iron lsx heads are there? Wasnt it only like 1-2 years in production in super early truck motors? And they werent real good to begin with. Anyone making aftermarket iron cores?

Forcefed86

iTrader: (4)

Plenty of iron headed cars making BIG power. They are using race castings with thick decks though. Tom Vaught over on theturboforums ran a 406 Pontiac at over 38lbs of boost with Iron heads/block for 3 years without ever pulling a head off. He also ran no head gasket…trapping mid 190’s in a 3000lb chassis.

I wouldn’t worry about the Iron causing detonation/performance loss. That’s been beat to death over the years. Still no valid proof to back up one is better than the other. Heat retention isn’t necessarily a bad thing and more IGN lead isn’t always a good thing. That aside there aren’t any decent iron castings out there for an LS I’m aware of. I’d go with the thickest deck 6-bolt alum head you could find and a nice aftermarket block/crank if you want reliability. 1300whp on OEM anything will be far from reliable IMO.

Lots of those “1000 HP” super cars really aren’t putting up great times. I think you’d be surprised how well your car would do if you got a clean pass with enough gear as it sits. Racing 1500ft isn’t going to generate much more heat than a ¼ mile run. Are you planning on half mile stuff too?

oscs

iTrader: (19)

Interesting to hear that. Yes 1/2 mile and more are on the horizon for me in the future. I spoke with Erik @ HKE for an hour or so about all this last night and his response about 4 bolt heads lifting was mostly tune related. He also suggested a process that strengthens the corner of the bores (water jackets) I posted about this in another thread a few months ago and no one seemed to pay attention. His theory is when the motor is making big power and the cylinders start to flex and the deck Becomes distorted it is happening at these areas with no support. This is where the head is actually lifting. He seems to think with the right tuning and attention to detail 1300 on a 4 bolt is very possible. With that said im not sure i want to take it there.. The constant risk of failure in the event of even the slightest change steers me away. After all the dust clears with block modifications/Crank/Studs etc. A 6 bolt block could be had and done with less trouble.

Forcefed86

iTrader: (4)

I agree. Unfortunately spending the big bucks on the right parts the first time around is almost always the best/cheapest route.

tblentrprz

Sounds like you were talking about pinning the sleeves to secure the bore?

Be interesting to know how many deck issues/distortion and head sealing issues (may not be lifting?) are on cars with mounts vs plates.

roastin240

iTrader: (13)

What kind of boost are you having to run to get there? Any issues with long duration pulls at those high levels?

rotary1307cc

iTrader: (5)

HP is not HP is not the case when speaking about cylinder pressure

stevieturbo

And why do you think this ?


I dont think he's done any long duration pulls yet ? The last event was just 1500ft I think, so barely more than the standard 1/4

oscs

iTrader: (19)

Correct. The longest distance I've held 25lbs or more is 1500ft at a time and I've only done it 5/6 times.

oscs

iTrader: (19)

These short awnser you have been providing lately are getting annoying. Speak up! Your one of the few ******** I actually listen to on here.

oscs

iTrader: (19)

I wish I could tell you how much I'm making for sure but it's all speculation at this point. I'll know shortly though as I scheduled a few hours dyno time to play around.

As far as long pulls, No clue.. Yet anyways.

oscs

iTrader: (19)

Im talking about pinning the bores not the sleeves, well a sleeve would be the same concept so yes. You are providing rigidity for the deck/upper cylinder bores. You have to obviously drill/tap these first. Set your plugs/mill/deck plate and bore like normal as this will distort the bores.

asubennett

iTrader: (6)

Sounds like Honda ****, with block guards etc... Ha ha.

rotary1307cc

iTrader: (5)

ha

everyone can agree tq is a good measure of average cylinder pressure

average cylinder pressure across one powerstroke delivers TQ


we have a cylinder pressure clamp limit with the 4 bolt deck, we know this



how do we make more HP without pushing past our clamp limit? RPM


lets say you take two engines the same size, both we limit to lets say 1000 ftlbs of tq


engine 1 tq curve is lower, it makes our 1000ftlbs at 6000rpm...... it develops 1142hp


engine 2 tq curve we shift higher but still the same 1000ftlbs, but at 7500 rpm.... it develops 1428hp


at higher rpm we have less dwell time at peak cylinder pressures too vs lower

rotary1307cc

iTrader: (5)

look at the SBF, it has been around forever, it is almost identical in head design, deck layout, borespacing, and fasteners


big power is made, how??


look at the small displacement motors with 4 bolt decks, they make big power and clamp, how?

We know we dont want cylinder pressure over X during a single power cycle to keep things sealed up. so how do we make more power? we dont add pressure, we just add more power cycles for a given amount of time

this is why timing plays a huge roll.... average cylinder pressure across the full power stroke may not change much with a modest change in timing

but peak pressures move a ton, very easy to unseat the gasket

Blown06

iTrader: (32)

These are pics of each side of the motor. You can see exactly where it was failing. Head gaskets where trashed but didn't torch anything.

Blown06

iTrader: (32)

It looks the the only hole that wasn't leaking was #8.

Here is a close up of #4 I think.

oscs

iTrader: (19)

I think I'm understanding. So what your saying is that with a broader RPM range (high torque curve) you are essentially spreading out the peak cylinder pressure over a greater distance.

oscs

iTrader: (19)

I've been meaning to ask you what heads your running. Also since you have the short block apart why not go see Erik? Talk to him about support the cylinders.

oscs

iTrader: (19)

Hey man there is something to be learned from those little bastards!