>>TVS 2300 Denali Conversion RCSB <<
08-23-2017, 02:01 AM
#61
I'd like to see this scavenging in a turbo exhaust that is pressurized. Not sure I can get my head around that.
When you have positive pressure on top of the intake valve when it cracks open, you're not gonna be able to create a strong enough depression (scavenging) in the exhaust system that it would be a stronger signal in the entire system to actually help pull more air in. In a blower set up is it just the opposite. In valve overlap, the pressure in the intake side will actually help push the exhaust out the pipe. Thats why bigger is better.
Hope I explained what is in my mind...
When you have positive pressure on top of the intake valve when it cracks open, you're not gonna be able to create a strong enough depression (scavenging) in the exhaust system that it would be a stronger signal in the entire system to actually help pull more air in. In a blower set up is it just the opposite. In valve overlap, the pressure in the intake side will actually help push the exhaust out the pipe. Thats why bigger is better.
Hope I explained what is in my mind...
08-23-2017, 05:58 AM
#62
I'd like to see this scavenging in a turbo exhaust that is pressurized. Not sure I can get my head around that.
When you have positive pressure on top of the intake valve when it cracks open, you're not gonna be able to create a strong enough depression (scavenging) in the exhaust system that it would be a stronger signal in the entire system to actually help pull more air in. In a blower set up is it just the opposite. In valve overlap, the pressure in the intake side will actually help push the exhaust out the pipe. Thats why bigger is better.
Hope I explained what is in my mind...
When you have positive pressure on top of the intake valve when it cracks open, you're not gonna be able to create a strong enough depression (scavenging) in the exhaust system that it would be a stronger signal in the entire system to actually help pull more air in. In a blower set up is it just the opposite. In valve overlap, the pressure in the intake side will actually help push the exhaust out the pipe. Thats why bigger is better.
Hope I explained what is in my mind...
Scavenging can really be broken down into two separate effects. One of them, and probably the most common one considered, is the imparting of kinetic energy during valve overlap from the outgoing exhaust onto the stagnant air sitting behind the intake valve as it opens. Using that exhaust helps get the intake charge moving, as we all know. But the more forgotten effect is the one that reduces inert gas mass in the chamber. If you have a camshaft that has essentially zero effective overlap but a really well tuned exhaust system, the kinetic energy from the outgoing exhaust gases don't help draw a charge in but instead just serves to further decrease chamber pressure as the exhaust valve closes. The lower the pressure as the exhaust valve closes, the less residual exhaust gas in the cylinder and the more air that can be drawn in on the next cycle. Many blower camshafts suited to relatively small blowers have minimal overlap, so there is a benefit to tuning the exhaust properly to deplete the chamber of exhaust.
The following 2 users liked this post by smokeshow:
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08-23-2017, 12:08 PM
#63
At first glance it does seem pretty counter-intuitive. But when you break it down, all you need for scavenging is a standing pressure wave in the exhaust phased so that the pressure at the exhaust valve as the valve approaches the seat is lower than the average exhaust pressure. It might still be at 20psi average pressure, but if that means a peak to peak pressure amplitude of 8psi, then you only have 16psi exhaust pressure when the exhaust valve closes. So more exhaust finds its way out of the chamber.
Scavenging can really be broken down into two separate effects. One of them, and probably the most common one considered, is the imparting of kinetic energy during valve overlap from the outgoing exhaust onto the stagnant air sitting behind the intake valve as it opens. Using that exhaust helps get the intake charge moving, as we all know. But the more forgotten effect is the one that reduces inert gas mass in the chamber. If you have a camshaft that has essentially zero effective overlap but a really well tuned exhaust system, the kinetic energy from the outgoing exhaust gases don't help draw a charge in but instead just serves to further decrease chamber pressure as the exhaust valve closes. The lower the pressure as the exhaust valve closes, the less residual exhaust gas in the cylinder and the more air that can be drawn in on the next cycle. Many blower camshafts suited to relatively small blowers have minimal overlap, so there is a benefit to tuning the exhaust properly to deplete the chamber of exhaust.
Scavenging can really be broken down into two separate effects. One of them, and probably the most common one considered, is the imparting of kinetic energy during valve overlap from the outgoing exhaust onto the stagnant air sitting behind the intake valve as it opens. Using that exhaust helps get the intake charge moving, as we all know. But the more forgotten effect is the one that reduces inert gas mass in the chamber. If you have a camshaft that has essentially zero effective overlap but a really well tuned exhaust system, the kinetic energy from the outgoing exhaust gases don't help draw a charge in but instead just serves to further decrease chamber pressure as the exhaust valve closes. The lower the pressure as the exhaust valve closes, the less residual exhaust gas in the cylinder and the more air that can be drawn in on the next cycle. Many blower camshafts suited to relatively small blowers have minimal overlap, so there is a benefit to tuning the exhaust properly to deplete the chamber of exhaust.
08-23-2017, 05:48 PM
#64
TECH Fanatic
Thread Starter
Well. I had to dispute my paypal for the tvs kit. The speed shop keeps giving me the run around about a tracking number or even an order number so I called PayPal and they are handling it for me. Thank god I made him send me an invoice for it. Should have it settled by September 3rd then I guess I'll figure out what to do next. To be honest I'm kinda jaded over this and not sure I want to be a part of the gas performance community after my expirence...
08-23-2017, 05:56 PM
#65
TECH Junkie
Sorry man but don't let it stop you. I absolutely could not be happier with my setup. Faster yes but not happier. Its reliable as fk and has just been a great experience all around. Just a bump in the road. After its over regroup your thoughts and push forward. It will be ok.
08-23-2017, 05:59 PM
#66
TECH Junkie
09-03-2017, 05:45 PM
#67
TECH Fanatic
Thread Starter
Love me some Paypal! I won my dispute and the money is back in my account!
Now... Should I drop back and punt and look into another route (i.e. Turbo or whippple) or just order a kit straight from magnuson and not put up with any BS?
Now... Should I drop back and punt and look into another route (i.e. Turbo or whippple) or just order a kit straight from magnuson and not put up with any BS?
Last edited by smokinlmm; 09-03-2017 at 09:34 PM.
09-03-2017, 08:56 PM
#68
TECH Junkie
That twin turbo kit available soon looks good. Ive been 100% pleased with my Whipple 2.9 though. At the time it was same price as Mag 2.3 and was more complete with tune and unlike the Mag it was legal. I didn't like the 1900 because I was planning for the future. Get a Labor day sale?
09-04-2017, 06:56 PM
#70
TECH Junkie
100% complete and tons of room to grow. Had to buy a few more tools bc I did it myself...I bought the kit on sale from a longtime well known member BlownChevy. It was a good experience. Superchargersonline.com