warping? lol.

Rob pushed, what, 15psi? Harlan now pushes, what, 15+psi? Harlan did 12psi on stock heads and gaskets! You're saying that an o-ringed, metal gasket motor couldnt push 18-20lbs? I guess we all just have to wait till harlan does it to believe it to be true. Its not cylinder pressure or air volume that lifts heads...99 out of 100 times (especially at a measly 10-15psi) its detonation.

John...you're getting WAY over your head if you dont mind me saying. The car is where you want it....just dont skimp on the motor! build a 346-375" motor with all the goodies for pete's sake. FAST, low-z inj., weldon, etc.


Ryan

 

You think I am talking out of my azz? The information I bring comes from people that know.. This is a direct quote from Rob Raymer when asked about using more than 15#'s of boost on ls1.com:

"I can't speak for ARE yet, but I can tell you what I know WILL NOT work.
ARP head bolts OR ARP head studs. We've used both and neither will hold the heads down.
O-Ringing the block helps, but still doesn't solve the problem.
We have used both an aluminum block and an Iron block. Both lifted the heads.
Torquing the ARP studs to more than 80ftlbs resulted in a broken head stud. Recommended torque by ARP is 75ftlbs. But ARP told us we "should" be able to torque them to 85-88ftlbs without a problem. Wrong.

Nick Agostino DOES HAVE A SOLUTION now. However, it will require buying a complete long/short block assembly from ARE, us, or one of their other distributors.
Nick and I have both spent a LOT of money in trial and error. I think everyone on this board knows that Nick and I are both more than willing to help anyone at anytime. But the fix required a large investment, special tooling, machinework, and a lot of time. For these reasons, Nick would like to keep a tight lid on the course he/we took he resolving the problems.

I can assure you of this, Nick and the crew at ARE will be a BIG PART of the first 8 second Forced Induction LS1. Hint-hint."

That post was in 01' This next quote was in 02:

"Unfortunately, it is still an issue. I believe the issue exists now due to the fact that we make more power than ever before. The new engine is 404ci (vs the previous 375ci.), and now with a billet stroker crank. Torque is well over 800ft lbs at the wheels. Creating even more cylinder pressure than before.

The head design from the factory is very poor when looking at it from a boost point of view. The heads have a thin deck, 4 small bolts per cylinder, and placed far away from the combustion chamber.

To answer your question, the holes cannot be simply threaded all the way to the deck. The block is too thin at the deck surface itself.

To clarify the "head lifting" problem. It's not so much "lifting the heads", but rather warping them. Let me explain; The heads are aluminum. From the factory, the head deck thickness is VERY THIN. The bolts are now larger and torqued to nearly double the original torque spec. The head bolt holes are far apart. The cylinder pressure is high under boost. Cylinder temperatures are high under boost. The heads try to lift, but the now larger bolts hold them down at the bolt hole areas themselves. So what happens to the pressure? It "lifts" the ALUMINUM heads BETWEEN the head bolt holes. After it does this a few times (literally), the heads warp between the cylinders (specifically, between the bolt holes of each cylinder).

We have, in a sense, hit a wall:

1.) The LS6 intake cannot flow enough air for much more Hp without creating a ton of backpressure.

2.) Fueling. We are already maxxed out on injectors (MSD 50#'ers in the rail), and two additional 42lb injectors in the up-pipe.

3.) Stock computer. It's just not very feasible to drive 680 miles (one way) to Ed Wright's everytime we want to change something.

But have we given up? Nope. Not yet anyway. We are working very closely with Nick Agostino (as usual), and hopefully will have answers to many of these issues very soon.

I hope that helps.

I did see in another post where ARE has come up with a solution and sells the whole longblock.. Then we get a comment from Mr. Inall:

"Guys, the absolute head/ block seal is not that difficult, just expensive and requiring the knowledge on where to source the correct pieces. However, I swear you all have a boost fixation.
Boost makes torque and torque destroys things. Since ANY form of professionally engineered FI makes more torque than one can usually handle, I believe you want the most HP with the least torque. This means, the least boost.
I cannot conceive of ANY reason to run 20 psi in an LS1 F body, unless you are trying to run over 170 MPH in the quarter, at 4,000lbs.
In that case, head/block seal, is the LEAST of the issues or cost !!" ,

Dave

"Or, take the smart approach, figure out how much power you need to run whatever performance objectives you have and then configure your specs to run the MINIMUM peak cylinder pressure necessary. As opposed to the " HOW MUCH BOOST CAN I CRAM IN THIS THING" approach !!! ."

Dave

ARE on this lifting/warping issue:

"Great thread!! Yes we have figured out how to hold very high cylinder pressures in the ls1 in a boost application. We do have a special head gasket/sealing/clamping procedure that we have spend some time and money on that we are very happy with. We are not advertising the details or any specifics with reguards to this and hope people can understand. All this information will come out in time and be general knowledge. We will be selling this in a complete engine package only right now due to the amount of machinework involved and the heads and block must be matched together.

I will say that we have had custom studs made for us that are quite different from the latest ARP Ls1's available on the market, there is quite a bit of custom machine work that needs to be done in order to utilise these and that is why we can not sell them as is. The studs that are available on the market right now can handle up to about 800flywheel hp, after this (exspecially in an FI application) another route must be taken.

We are tooled up right now for the machinework and will be glad to supply anyone with an engine that needs this type of work done, hope this information helps."

Mr. Inall again:

"Nick, it rather depends on how you go about achieving the 800 flywheel HP, ( or 1000 if it comes to that).

If you have a 300 cfm intake tract,(with intake bolted to head), coupled with an intake manifold with even air distribution under pressure, low pressure loss air ducting, correct design pistons / combustion chamber / camshaft and a quality aftermarket engine management system, obviously on appropriate octane, you will make 1000 HP, flywheel with less than 12 psi boost. If you have also chosen an appropriate compression ratio, there are no head gasket issues using correctly installed stock pieces.

However, equally I am sure, if one went about the exercise differently, I am sure there could be head sealing issues. As I said, it is a question of approach, NOT finite power numbers,"

Dave

ARE's comeback:

"I agree Dave but we are talking about factory Ls1 heads and intake to do this with. I think that in these situatuions we may need to run more boost in achiving the 1000hp mark and the cylinder pressure needed to do this will give us the problems some are finding, in perfect conditions(not many on these street/race cars) I agree that the issues will be less but still there to a certain extent.

On the block question, we have been succesfull with the iron as well as the aluminum and even the re-sleeved aluminum block.

We are just about to release our FI version of the aluminum re-sleeved 5.7 block and will house a bore up to 4.030. This block with all the appropriot changes will be able to handle very high hp levels that could not be attained reliably before, no pricing yet but way off the C5-R block. At first we will be selling them as complete shortblock assemblies and then move to the block fully machined on its own at a later date."

They go back and forth about diffent intakes and such.. Anyway. This is getting long.. I had to justify my comments earlier and also I had to razz Ryan. I have not heard from him in a while. Ryan where have you been man..? I was about to email you, because I have not heard from you in a while..

 

You guys can thank me later for using the SEARCH function.. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> I am with John on this one. No need to take chances.. I am going this same route and NO WAY I am forking out a ton of money w/out doing my homework this time.. I want something that is going to run HARD and LONG. I am getting tired of seeing people post crazy #'s and then disappear only to find out they have exploded.. We have some of the smartest people in the world in here. No way the Ford guys are smarter. It has to be that we have a weak head design when it comes to forced induction. I think there is a way around it.. If there is we will find it and take our rightful place in FI Heaven.. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

Sounds like ARE is either increasing the stud width size and holes in the block and head or even adding new holes if that's possible? Just a guess.

I see SC'd C5's running 650rwhp without too much craziness. Past that it gets pretty complicated.

 

I'm sorry but everything I've read on turbocharging points to detonation as the REAL reason why heads lift etc.

Honestly when I see Harlan running 16-20 PSI on his motor testing on a load based dyno over and over again it makes me realize that it's not magic. He's got the tuning right with no detonation. How he does this with a stock computer? Well that's magic to me. I'm not even gonna attempt that one. But there are engine management systems with WB, EGT and BOOST references that I think can do the job.

But then again wont know till we try it. Harlan I know has run 16 and higher. How many heads has he lifted? Is his head clamping anything radical? I don't think so. At least not from what he told me.

 

1) Ryan, nowhere have I said I would NOT be doing any of things you mentioned in your above post to me. Rather than assume, wait til I post what my 2003 combo will be, you have it all wrong. I know exactly what 90% of the combo will be. I had to do a lot of research directly with folks I know.

2) Chas, using the Mustang example's, he's at ~790rwhp, 3300 raceweight for 8.97@154. So I think that 800-850rwhp for a 3400 raceweight can run 8.90's.

3) Vince, I have like you done a lot of reading on various engine builds. I look at it this way. I see (Matt) Harlan's car as an excellent example of a perfectly tuned car. Matt saw 15psi. I think he maxed out his turbos. Rob Raymer's car? I know he worked hard to run that 9.94 back in 2001. He worked with ARE and Ed Wright and busted hump to get that car to run the number. I personally feel that his motor or at least one of them detonated or had machining issues. I think in spite of possible issues outside of his control he ran a killer number and it was two years ago. In the interim, Matt's done pretty well, running 142mph on the limiter with a 3600lb raceweight. I think that there are probably a number of LPE TT cars out there are probably running over 10 psi and are in the 10's. Steve Dummeler's pewter TT C5 is off the chain, we cannot even begin to discuss that car since the motor is entirely C5R at this point, and I don't even know when that motor still ran conventional cylinder heads (I'd love to).

4) Mello, bigger studs not more.

I think it's all in the tune personally. I was talking to that Stang friend, and he tunes his car and other folk's cars initially at 11:1---11.4:1 AF. He does supplemental tuning at the track. I think the actual load on the street or track is far different than on a Dynojet. We should start conservative and work our way down. When you see some NMCA and NMRA cars run down the track sometimes they have a big plume of black smoke behind them... They are running those high HP cars rich to keep them together. Going for a huge dyno # is not their goal, having the car live thru an entire racing season and run 150 passes is their goal.

 

I also think it is pretty much a detonation issue.
Detonation causes a extreme very brief spike in cyl pressure. Cyl pressure Shoots through the roof and lifting a head is 1 side effect.
When I was into supercharged 5.0s back in the day, head lifting was a popular discussion.
Guys were pushing a lot of boost and the tuning needed was being worked out.I can't even remember how many head gaskets I went through.
Sure good studs and good gaskets are needed and o-ringing may also be necessary.
But the real issue is not boost pressure but detonation.
It can happen so fast you won't know what hit you.
Steve

 

PSJ,

I would go for the most headflow and exhaust flow you can get out of your heads, intake and exhaust system.

I would also look at the most efficient intercooler/aftercooling possible.

That way you can run less boost to acheive the same power, be able to run a lower octane for a given power level and have less strain on parts.
A TH400 with GV OD would probably be necessary or a fully built 4L80E.

Good luck,
Chris

 

Rob also used a non-load bearing dyno for his tuning and testing...meaning they were just about guessing at how much load his 4000lb car would push in 3rd gear and 130mph. They were probably good guesses...but why take the chance? Find a Mustang dyno.

BTW, my comments in the first post were based on your earlier comments on running a stock PCM and 50lb injectors. I may have misunderstood.

 

yep the 5.0 has just 10 headbolts.
I disagree our heads are thinner also.
The 5.0 also suffers from a wedge torqued intake and the bolts were usually torqued at different specs for the top bolts to help offset that.
The ls1 heads use the series of small bolts to offset intake torque and the plastic intake is only torqued to a very low threshold anyhow.

Just as you say Harlan is only 1 guy Vince, So to is Rob.
Fuel and timing are critical at high boost pressures.
You need to get that peak cyl pressure to happen around 20 degrees ATDC.
Time it to early and you end up with cyl pressure trying to push down on a piston with not enough rod angle.
Then pressure shoots up and detonation can happen.
Time it to slow and you lose power by chasing the piston down the bore and also send an unburnt mix out the exhaust port whcih also creates problems.
Guys are new to the ls1 motor and how the motor reacts to boost.
Timing requirements and fueling will take a bit of time to be common knowledge.
You can't just go and blame the head fasteners or head deck thickness because you can't keep the heads on it under high boost.
I pull plugs everytime I make a change.
Even if Harlan comes on and spills all his tuning details it probably won't be right for my motor.
I would be intersted to hear more on what he is doing though <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Steve

 

I have some Mustang friends as well that boost. I will have them jump in the discussion soon..

 

Sorry Ryan I was originally going to build a milder combo and have decided instead to go a little bigger on everything.

I'd be interested to see some other folks chime in who have LT1's or 5.0's or whatever, to get some thoughts on some of the various points. I tend to be more impressed with the large number of 5.0 cars that run 8's and 9's with forced induction. There have only been like 10 LT1 cars in the 9's pretty much that I know of... One friend is going 9.4's (Chris) and I'm sure he can run 8.80 no problem with cogs... He's running a big Weldon, I think his heads are o-ringed too.

 

This is a great thread, keep the info coming
I am currently building an 346 Forged top end to insure I have a long happy life with my ATI D1 Powered LS1.
I bought a new never assembled 02 LS6 block. Chris@diamond told me to go with a Forged 6.125 Rod with their 11502 pistons. I am going with TEAs 73cc chamber stage 1.5 head.Compression should be 9.2-9.5-1 with this set up. ARP head studs and cometic gaskets(still don't know what pn tho)
I am not looking to break any hp/tq records but I will want to run 15psi max. Does this combo above sound like a good one?
I am using my stock crank but I am having the engine builder nitride it though.
I want to keep the CI low because I see 302/347stangs putting out huge numbers with FI and boost in the teens in my area, so I am a firm beliver in more boost less motor.
Please offer advice but dont knock me on the set up, I see what harlan has done and will follow. If something might not work please tell me why.
Thanks,
J
PSJ sorry for hijacking this part of your thread but it sound similar to what you are doing.

 

I agree John.. This is a good thread.. It's good to shake it up a little to get real answers.. I requested some fast ford guys in my area to register and give their opinions.. Hopefully they will chime in this weekend..

 

I agree with the detonation issue, but most of the same parts that were used back then are still being used today.. We keep comparing our cars to mustangs. The head design of a mustang is different and mustangs heads are not as thin as ours.. I keep hearing people use Harlan as an example. Harlan is not the FI God. One car out of many.. How much boost has Harlan run through his engine? When is Harlan going to chime in anyway..? He rarely responds back to emails. I am not saying it cant be done, but from what I have learned on the boards. Not everyone tells the whole truth. Harlan needs to stop smoking 10 packs of cigs a day and start helping out or atleast do his moderating duties.. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

I occasionally talk to Harlan on the phone and he's not at his desk every day, he does some travelling.

Vince the parts are the same, but tuning is more advanced. Take Steve's comment, perhaps Raymer's car was still underfueled... Was his car lifting heads only in 3rd which would mean under full load and under full boost...

Take for an example a number like 700rwhp. He did it. But, he did it with 50lb injectors and some piggy back injectors? Again, he was a pioneer. But I'm not convinced, nay for me it's the opposite, I take the view that he was underfueled or needed some more 'at the track' tuning which he could not get at the time... Also, with piggyback injectors is there any knowledge of whether individual cylinders might suffer?

Mustang 5.0 heads lift a lot too, they don't have a lot of head bolts right Steve?

Raymer has LS1 Edit now. I'm sure whenever he next runs his car he's gonna step it up bit by bit.

 

Well, the head bolt pattern around the cylinders is almost identical between the 5.0/5.8 and the LS1. Ask any of the 5.0 guys when they blow a headgasket or lift a head what the reason is and it is going to be detonation. I would think Rob had hit detonation to create the heat and presure required to warp a head in that small of an area. With the O-ring it held the gasket in place longer letting more detonation occur. Just because you do not hear detonation it does not mean it is not happening.


When tuning for FI are they running max advance for that rpm when tuning?

Lets say the max possible total advance at 6000rpms is +25. Due to some noise picked up by the knock sensors while tuning the max advance seen at 6000rpms is +22. At some point when running the motor the knock sensors do not hear any noise and bump the timing back out to +25 and because of the extra 3 degrees of advance detonation occurs.

The big difference between the EFI windsors and the LS1 is that you can set the true timing of the 5.0 motor by pulling the spout connector. The 5.0 does not have knock sensors to pull the timing out. You have a set spark curve that does not vary once set so there is no unaccounted for spark advance out there that could show up if not accounted for.


Just some things to look at.


Thanks,
Jess