Halltech will be producing headers with this quality in the very soon. Once we move to Oxnard, this will be the quality of the headers we will bring to the LS6



These are made by our man Biggie for the 427 AC Cobra, but he assures me we could produce the same quality for the C5.

They would be our own design, not a knockoff of other headers on the market.

We would sell them exclusively to the forums at first under a Group Purchase Program for prices that will kill the competition.

Many want long tube headers, but personally I think they are a waste of money on the Z06, unless the purpose is to eliminate the pup cats on the 01.
That will pickup a few more (5 HP) ponies.

On the 2002 our goal will be 7 to 10 HP with these headers, and major torque at the bottom rpm range where we drive most of the time.

Let me know what you think. We already have 11 customers to be on the Z06 vette forum poll.

25 or more would bring the price way down.

Jim Hall


[Modified by Jim Hall, 2:18 AM 5/5/2002]

 

7 to 10 peak HP gain? What sort of average along the entire curve?

 

I'd be interested but I would want long tubes.

 

I question the value of headers on any production LS engine. The cams were designed to work with the production exhaust system, and they have virtually no overlap in order to keep exhaust backpressure from affecting output.

Short tube headers have no value because the primary tubes are too short to take advantage of the primary wave reflection within the operating range of the engine, and the LS6 cast iron manifolds are designed for smooth flow. Typical shorties would probably increase flow restriction unless they are very carefully fabricated. At best, it would be a push. A header with a primary tube length of 34-36" would provide some benefit in the upper range IF the cam had some overlap.

The '02 LS6 cam features very retarded inlet timing (point of max lift is 120* ATC versus the more tradional 110*) relative to traditional cams. This is illustrated by the split overlap point (point at which both valves are open an equal amount) being about 8* ATC vesus 4* BTC for traditional high performance small block cams. Normally, delaying the inlet event increases top end power, but hurts the bottom end because of flow reversion at low revs, but somehow GM Powertrain has managed to maintain tractor like bottom end torque while producing outstanding specific horsepower output at the top end. I think their secret is the inlet port and manifold, which provides excellent inertia tuning. In any event, the torque bandwidth of the LS6 in production trim is utterly amazing!

Long tube headers, or better yet, tri-wye headers, would provide some benefit if the cam had some useable overlap, but then you'd be likely to have idle quality problems, loss of low end torque, loss of fuel economy, and emissions problems.

Check out the following thread. It has some insightful comments from John Juriga and others at GM Powertrain on the philosophy of the LS cams.
http://www.idavette.net/hib/02ls6/index.htm

Duke

 

I have been saying the same thing for years, but no one will listen. Scavenging and intake flow inertia from exhaust wave tuning is impossible with zero overlap.

We picked up only 3 HP with the B&B headers and 4 with the Borlas. This was peak HP. There was an increase in torque at low rpm with the Borlas, but the price vs horsepower is there only with the Borlas, but the B&Bs are manufacturered closed to the stock configuration.

Both lose to the stock Z06 headers for heat retention, since iron retains heat much more effectively and thereby increases velocity of the exhaust.

Both the B&Bs and the Borlas increase the power to weight ratio somewhat due to 15 lb. weight savings.

I personally prefer the quality of the B&Bs.

If there is no market, fine. More time for other projects. We will be building a bunch of twin turbo Z06s.

Jim

 

The American economic system rewards those who provide what consumers want to buy, and unless consumers educate themselves as to what works and what doesn't, it's their fault for throwing their money away, not the vendor.

Until late model Corvette owners understand the signficant differences in tuning philosophy between now and the sixties and have a better understanding of the physics of the internal combustion engine, they'll continue top spend money on forty year old hot rod techology that is long obsolete.

A couple of days ago in another thread I suggested that the best gains on the LS6 would be from head porting. Several dissented, and after looking at the port sections in the referenced thread, I concede. There may be little to gain.

For sure the LS1 heads can benefit. I was appalled by the short side radius, which was more like a square corner. Other than maybe some work on the valve pockets the LS6 heads look awfully good as cast.

Like John Juriga said, all the low hanging fruit has been picked, and it will take some savvy system engineering to improve on the LS6 without a signficant compromise somewhere else like idle quality and low end torque, fuel economy or emissions.

With an old 350 small block you are doing VERY well to get 80 percent torque bandwidth from 2200 to 6200 and 300 RWHP. The LS6 makes NINETY PERCENT of peak torque from about 1500 to beyond the limiter and 350 RWHP while achieving nearly 30 MPG in highway cruises and LEV emission status. The best thing you can spend money on is good maintenance, and just enjoy driving the beast.

Duke

 

Man Jim, that TT looks SWEEEEEEEET :D How much will that ***** cost in kit form??

 

Once again, I concur with your assessment of the LS6 heads. If you look into the changes made to the 2002 LS6 engine, you will see why we picked that engine as our foundation for bolt on turbocharging. From the .551" lift and no overlap cam, to the high spring rates, to lightweight Potassium/Sodium (KNa) valves, and even tighter piston to wall clearances, piston coatings for lubricity to accommodate the tighter bores, to a ring pack with higher tension and oil control, this new LS6 engine is a made to order turbo engine. The compression ratio would be ideal at 9.5:1 rather than 10.5:1, but the additional compression ratio lends itself to a larger 1.06 A/R turbine ratio for less backpressure and virtually no turbo lag. Lower compression, is however, preferred in almost all turbo applications.

Our intercooler is so large and gets direct high pressure flow from the chin spoiler, that the temperature at the manifold should be close to ambient up to 12 to 15 psi. We will be running 8 psi, with variable boost control.

We have some drag racing tricks up our sleeve that are very inexpensive and will find its way into our kits. One such trick made even Biggie take notice, and he’s seen it all (almost).

We also have two LS6 Crate Engines (2002) that we will be "building" for major (1000 HP) applications, with O-ringed sleeves and other bottom end mods including a special crank and rods, for the all out application. The motors should be delivered this week. Cam, heads, and valve gear will remain unchanged.

Kenny Duttweiler has taken 6 cylinder engines to the edge of the envelope with boost levels that have made over 1800 HP! Incredible but true.

 

Well, interesting commentary, especially from Jim. Now, that said, the collector design on these headers is impressive and expensive to produce, not to mention the beautiful craftmanship. The collector is a critical component in header design and if done properly (as these appear to be) will dramatically reduce reversion. Now, before you argue the Zero overlap theory do not forget that there are 3 other cylinders connected to the one at peak flow. Total manifold pressure and flow will effect the residual pressure in any cylinder that is near the end of its exhaust cycle and gets "charged" by the very high pressure from an adjacent exhaust runner that is peaking in pressure. Take a look at formula one headers and you will see many similarities. I look forward to seeing dyno numbers especially in light of how open and honest Jim has been.


[Modified by Jbrady, 9:13 PM 5/6/2002]