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High boost headgasket question

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in 2022 I think I'm at the point where I can say that if you need more than a composite will do, you also need a filled block. Also when you are playing around at very high boost like 49, you can't let it hit the revlimit or do things like that. Does all sort of wierd things to combustion events. The automatics require a different approach to tuning than a 5 speed.

Last thing, old heads get soft and they don't retain a head gasket well. Sometimes it's just best to goodbye to an old friend. xzy2011009 studs that you torque to 6000ft*lbs and pull the block through the head won't help if the head is soft and flexes between the studs.

Bringing back from the dead but how much boost are you running if I may ask? I'm running a 76mm with L19's and steel o-rings in the block.

Was just at the track and running 49 pounds of boost but coolant started spraying from the side of the block. Don't believe it was the gaskets fault though, but old stretched out, not properly handled L19's that were the problem. So ordered new ones. Still makes me wonder how far I can push it though. Wondering if this setup can handle 60-70 pounds of boost. Guess I'll find out but just wondering what you were doing. Thanks!
Why do you need 49psi? Trying to go 7's? Why don't you start out soft and make it work right. With a 76 on it, that thing should go bottom 9's at 25psi. Parts are really getting too hard to come by to ruin on these hail mary bs passes.
 
Block is half filled with aluminum rods as well. The rev limit was an oopsie on my part but yeah, I need to pay closer attention to that from here on out. Wishing I had this new shift box like BAD right now so I could go ahead and stall up in 2nd gear and not need to manually shift. Oh well, have to just not be stupid until then.

And 7's? Why yes. Lol. Thinking I'll turn the boost down at least until the fuel is dialed in a bit better though and try and save myself the gasket headaches. Then back up it goes. Would love 7's but 8's are a more realistic goal for me with what I have in it. So long as I'm not stupid anyway.
 
I don't think you need 49 to run 8's. It really looks like you need to slow down and work out the kinks before you keep going out loaded for bear.

story time. Back in the day it used to take almost 40psi for my car to go 11.0's-10.8's. And I was trying all sorts of stuff to get it to go quicker. All the boost, big f***clobbering turbo's, 8000lb pressure plates, all the boost all the timing. I remember thinking "I have to get this car to go like 1.3 60' " I was so caught up in trying to get it to leave, I never reallized how bad the mid track performance was. Ended up being the end of the season, and was prepaid for a track rental and didn't have a clutch for the car. So I put what I had back in and turned it way down. Figured I'll just go and have fun. Car ends up going 10.99 at 19psi. I learned so much from that track trip that was sure to be a dissapointment. Compare some datalogs and it it was easy to see why it worked so good at low boost. I would have never even seen, had I not turned it down. "Low boost, f*** that I need 40 if I want to go fast" Fast forward a few years and now the car goes 9's on less than 30psi. Anyway, less is more. Back in the day they were going 8's on cast wheel 72's shift never act3200's hks 272's and 30psi. Why do we insist on going backwards.
 
Leave the gasket dry. No need for coating. Either it will seal, or it won’t. An “adhesive” isn’t going to fix a poor or aggressive tune.

Boost is irrelevant. Like I said, the car made 830fwhp. If that isn’t turned up, I don’t know what is.

This car was run fairly rich as it was on gasoline. Per class rules. So my serious tuning strategies started and changed with that car. We also ran water injection in that car. Both pre and post turbo. I assure you the stress and cylinder temperatures and pressures are far different running five miles flat out versus 1/8 to 1/4 mile.

I had to completely relearn how to tune with that car. And that was in 2007 or so that project started. I have learned to leave some on the table. It took us three years to learn how to keep head gaskets in that car.

The engine prep was nothing special that anyone could replicate. Off the shelf Felpro composite head gasket, no orings, conventional ARP studs torqued to 120lb/ft. The true and only key was tuning. Learning what to watch and listen for is most important. The only time we/I have had short head gasket life in a 4g63 is with copper head gaskets over 1000whp. And that is just part of the deal with copper gasket anyway. Pretty much no “long term” problems with composite, MLS or any other gasket than copper from 700-1000. These are race cars and we are generally in there for one reason or another frequently at those levels anyway. Head gaskets is just not a problem I have dealt with since before 2010.

That particular land speed car made us go back to older tuning strategies. Reading plugs is not something that can be overlooked or not be done period regardless of how much data you have. That tells you exactly what is going on in the cylinder. I also rely heavily on individual EGT temperatures. Again, like the plugs, that data doesn’t lie and is universal. Shit melts at certain temperatures. Regardless of whose name is on the box of parts. I found some temperatures that work pretty darn good for just about any type of racing. Something else I rely heavily on it turbine back pressure. Being on the wrong side of that will cause more headache than you want as well. Same thing, there are magical numbers there as well. A Dyno is a very good test bed for maxing out turbo and turbine pressures.

Sure, you may be running 49psi now but, is it useable and good air? I see this a lot with 16g pump gas cars here at elevation. “Turning them down” usually means more and safer power.

And with the land speed cars we are usually starting our runs in the 100-110* coolant temperature range. The drag stuff given short turnaround and layout of the track I try to target my temps to be under 140* before I pull into the burnout box. That means towing the cars to the line. Again these are race cars. Not street cars pretending to be race cars. The colder you can get an engine the better. 216* is not acceptable to me at any point, ever.

Another car was retired and sold I did all the work on. 83mm, auto car with a 300 shot. Moved him away from orings and copper gaskets as he was unwilling to service the car himself back to an MLS. With an aluminum rod 7 bolt(not even close to my choice for obvious reasons) the motor stayed in the car untouched for three seasons until it crankwalked running 160mph here at altitude. We fought transmission and driveline issues but, the motor did not come apart for three years. And that was a very basic dsmlink car. No real data besides a wideband and knock sensor.

Plain and simple, it is either turned up too far or there are steps you are missing. Failures happen racing, sure, I just really try to leave my problems in the garage before I go racing. My friends, not so much.
 
Bastard is right. You need to slow it down. I have gone 6.4@112 in the 1/8th at elevation with a 6466 maxed out at 39psi. On all season H rates tires.
 
Next time text me you’re going and I’ll come along and help out. I can at least hold a flash light and provide moral support. :p
Well, I'm trying to go this Friday night. Lol.

Car is about back together but a been a busy weekend. Just have to reconnect the oil return line at the oil pan, connect the wastegate hoses, get it on the ground, and torque my wheel. Gasket is on (dry) and torqued to 104. I've been doing some thinking over the weekend about my plans though. When it hits around 7k rpm's the needle then moves really quick. I don't really wanna manually shift it because it'll zip on up to 9k really fast once it's moving, so think I'm gonna let the shift box do it instead to keep it off the limiter. Problem with that is being able to stall it because I'm waiting on my new box to stall it in 2nd gear. So I think what I'm gonna do is just hit the gas in 1st gear, but hit the nitrous somewhere between 2-5 mph and take off from there as soon as it starts moving and keep it on through most of 1st before shutting it off. Not sure how long it'll take to shift so I'll set it for 8k to start with, inspect, and bump it up from there. Debating on somewhere between 9000-9500 rpm's as my limit. Starting with a 50 shot and work that upwards as well as things progress. Turn the boost down to 30 for now.

Also, I didn't really consider 49 psi all that much because I was planning on 60-70 at full tilt, just depending on what the car likes but that's the test I have to make to see, once the afr's are dialed in. I can't understand a car going faster by turning the boost down, if maybe it was above it's efficiency range to begin with, or maybe it's just heating up the air a good bit, etc. But I know this turbo is pretty big and loves the upper end. I have two 1000cc nozzles for my meth injection so it's definitely flowing a lot and keeping it cool. If things are looking good as far as afr's and timing goes, IAT's looking good, the turbo is within it's range, etc. I can't see any reason it would be going faster by turning boost DOWN. I'd have to hear the experience of what y'all are seeing though in that regard to understand that one. Not doubting y'all. But makes me wonder what the full picture looks like to get a full explanation as to why it's happening. Sounds to me like something had to be off at the higher boost levels to be making it run slower at the higher boost levels.

But anyway, appreciate the input either way, and the good discussion on it. I searched and searched and see people talking about high boost of 30 psi on the gaskets, which isn't like "high" for today's standards. So really curious to see how far this thing will go at X boost or X power level and track times. Most are on an MLS when getting to higher numbers so it's hard to get much data regarding this. Guess we'll see what I can do at least. Just being careful with the tune, rev limiter, etc.
 
I can't understand a car going faster by turning the boost down, if maybe it was above it's efficiency range to begin with, or maybe it's just heating up the air a good bit, etc. But I know this turbo is pretty big and loves the upper end. I have two 1000cc nozzles for my meth injection so it's definitely flowing a lot and keeping it cool. If things are looking good as far as afr's and timing goes, IAT's looking good, the turbo is within it's range, etc. I can't see any reason it would be going faster by turning boost DOWN. I'd have to hear the experience of what y'all are seeing though in that regard to understand that one. Not doubting y'all. But makes me wonder what the full picture looks like to get a full explanation as to why it's happening. Sounds to me like something had to be off at the higher boost levels to be making it run slower at the higher boost levels.
Well for me it's not necessarily slower at higher boost. Nor it is going faster on less boost. It's taking less power to run the same number. it's getting better at utlizing the power. I guess I'm not really sure if it will go better turned up, I've not turned it up. It is running what I want to it, and I'm not beating it to death to do it. Yes, I do want it to go better, but turning it up to moon boost is not going to get it there. I want it to go 8's and it will go high 9's on command, at this point I suppose I could probably turn it up enough to run a bottom 9, but it's gonna take all the boost and 160+mph to do it. Probably end up breaking a cylinder wall and/or having hg problems doing it. And I still won't learn anything about making the car quicker. I need to get the car to 60' good and consistently, work the et down at the power it's at, and then we are at time for moon boost and the hail mary. Where it is right now I can work on the things that are hard to figure out, and not worry about torching a motor every pass.

I guess what I'm getting at is for trying to go fast, making power is like 10% of the whole battle, and it's hard to figure out the other 90% when the things broke every other pass cause it's set on kill. Look at the last pass I made in the car. 10.16@141 with a 1.65 60'... Any of the other stick shift guys running that et at that low of a mph are 1.3-1.4 60'. Even many auto guys don't run that good of an et at that mph without a killer 60'. That didn't happen over night, and I'd never have figured it out with the car at 45psi.
 
I never said anything about turning the boost down. I said turn the car down. Do what bastard is doing and learn the car. Boost pressure is irrelevant if that is the only data you have. Having a chassis work correctly will make up for lack of horsepower.

The correct timing, egt, back pressure and fuel mixture are what makes them survive. What they spit out of the wheels is just a bu product. If you continue to chew through parts at the power level you are at, you need to step back and change your approach. Like I said, I was making quite a bit more power than you for multiple seasons.

Shooting for certain boost numbers is not the way to tune. Sure, the 4g63 cylinder head flows like shit but, I have made over 850whp with a cast wheel 74mm before at altitude. The car was very well setup and you would be sickened to learn it was at a mere 27psi.

Knowing how to use the data and how to listen to the car are what separates the pros from the joes. I can only assume you have no real data on the car besides an intake temperature sensor and a wideband. And tuning for knock is also incorrect. Very few platforms and systems use a knock sensor. It is utterly worthless and primitive technology.
 
Maybe I misread. But no, I use way more data than that. And I'm religious about reading plugs. I preach that to people all the time. Even made a Facebook group just for the purpose of reading plugs.

I'm not new to tuning but probably read the reply wrong. When I mentioned my temps being at 216 earlier, I didn't even realize they had been rising until after the run. Was trying to pull up to the tree but they had me wait, and wait, and wait due to the car in front of me. That's not a normal thing I do, and temps are usually MUCH lower when going down the track.

The exhaust is only 2 feet with a 4" pipe so any back pressure I have would be at the turbine housing or restriction in the head.

I don't really trust knock sensors, and don't really even trust egt gauges unless I'm looking for the delayed information it's gonna give me. I take a few sets of plugs with me and do a lot of inspecting while I'm there. I know a 16g was mentioned and I can see it being true to pick up power with that small of a turbo if the boost is turned down.

I totally understand what y'all are saying though. Learn the car before going for 7's. Which I agree with. Just didn't want y'all thinking I'm a TOTAL idiot. Just 99% one. Lol. But don't wanna get off topic of someone else's post as well. I never claim to know everything and I'm always coachable no matter how far along I get. Would be great to stick to the original purpose of the post overall though, but I appreciate the input.
 
Then you need to use faster sensors and hardware. Egt numbers are invaluable. Things melt at certain temperatures. Plain and simple. And egt data is something you review. Unless you have warning lights or an ecu with a safety measure to shut things down. I run a FuelTech ecu in my race car(non dsm/4g63) so the safeties are run through that and the dash.

And yes, the backpressure will be in the turbine housing. I measure it at the inlet of the turbine. Even with a turbo like that you would be shocked at how far on the wrong side you are with a shitty flowing engine like an early 4g63 is.

Unless you are changing the tune while you are racing, you honestly don’t need to be religious unless you are running nitrous with that much frequency.

And if you are referring to 7’s in the 1/8 mile, that can be done going in reverse with a setup like you have. If I ran a 7 second 1/8 mile with a 76mm turbo, I would quit. 7’s in the 1/4 mile is something to strive for certainly.
 
Lol. Definitely not 7's in the 1/8th.

I'll settle for 8's though, in the 1/4. Say that now though, and then it'll feel slow and I'll want more. I use to want 12's way back in the day....when it was harder for folks to achieve.
 
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