Unofficial Message Board Home of Steve Wood
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Don't get me wrong, Steve... a small amount of valve overlap 2-6* (typical in a mild NA performance cam) can work wonderfully in turbo engine, especially those 500-650hp range street combos. High overlap is no bueno. Yet, there is a point were we transition to race car mode and a spec cam is required.I specifically chose the LS9 cam in our Procharged LS2 because its had more negative overlap than the stock cam, and caused an effective drop in dynamic compression. Handy when you are force feeding an 11:1 engine. Conversely an 8:1 V6 needs more help off boost, so positive overlap is beneficial.https://www.lingenfelter.com/PDFdownloads/12638427.pdfEarl: Back pressure. Back pressure. Back pressure. :p
KOENIGSEGG Has it figured out. Camless, and a whole slew of other cool shit.
When GM came out with the LS series, all bets were off. Chrysler has gone nuts...and the most impressive thing to me is that this stuff has a warranty...smhWe do pretty good to be 32 years into the game and still getting better.
I have always been surprised by how well the stock camshaft worked under no boost conditions. Engine is pretty peppy in NA form. Be interesting to see the turbocam profile vs the na cam profile.The engineers came up with a pretty good combo right out of the factory for 1986.
I disagree with Earl's comments about a turbo engine won't run well with a NA cam. Many of the cams we have used to get better performance are NA profiles. The Edelbrock 204/214 was very popular early on. Then we had/have the 206/206, 208/208, and the ever popular 212/212. All of these are NA profiles but they work. The really early cams like the 218/218 and such also made power but gave up the bottom end and have mostly gone away with the advent of better turbos.
Brad, you used too big a turbo for the combination and it did not have a chance to come into the zone where it was designed for. It was lazy.
That is really our problem. Most engine programs are aimed at high end engines whereas many of us are looking at the other end of the spectrum.The more I look at the new gen turbos, the more potential I see for low rpm, long-lived street engine's that will work. yeah, I know a billion cycles on a cast crank can cause failure pulling out of your driveway. It's no questioning that the series of turbos that included the 6262 series really stepped the game up and guys are going a lot faster as a result. I suspect some of these new units are going to make them look obsolete.Now, all we have to do is to drag Brad into the 21st century turbo-wise so he can kick rich kid azz even worse.
Earl said that because what is commonly referred to as a 'turbo cam' is one with very little overlap, where as a 'n/a' cam is one that has the correct amount of overlap. Not to mention a 'turbo engine' is normally built with much less that optimum usage of intended octane.
Something to think about. Years ago Jim Dotson was running 8.0's with his twin turbo stage 2. Health issues caused loss of his comp license. He removed the turbos and install a new intake and carb. The car ran constant 10.00's and won many bracket, Q8 and Q16 races. He was unbeatable until he passed away. Best of my knowledge he never opened the motor and used the turbo setup internals with the carb. Go figure.
Quote from: earlbrown on July 28 2018, 03:02:23 PMEarl said that because what is commonly referred to as a 'turbo cam' is one with very little overlap, where as a 'n/a' cam is one that has the correct amount of overlap. Not to mention a 'turbo engine' is normally built with much less that optimum usage of intended octane.OMG, Earl is now talking in the third person just like Brad! If one of them starts referring to themselves as The" Earl or Scoob, it's going to be time for some chemtrails and population control!
Quote from: Steve Wood on July 28 2018, 10:45:18 AMThat is really our problem. Most engine programs are aimed at high end engines whereas many of us are looking at the other end of the spectrum.The more I look at the new gen turbos, the more potential I see for low rpm, long-lived street engine's that will work. yeah, I know a billion cycles on a cast crank can cause failure pulling out of your driveway. It's no questioning that the series of turbos that included the 6262 series really stepped the game up and guys are going a lot faster as a result. I suspect some of these new units are going to make them look obsolete.Now, all we have to do is to drag Brad into the 21st century turbo-wise so he can kick rich kid azz even worse. I have an end game for this car...and I'm not done yet. The plan is to have Tylers plug-n-play return line on the car and 340 pump in it before I put it away for the winter. I'll need it for more HP next spring...