Dyno 3/23 Noon @ Synapse?

[Captain Moai]

Very true. It can't hurt.

On the upside, the two curves are nearly identical, with the supercharged curve just... larger It's a damn fine powerband.

[JClark]

Originally Posted by 1320ride

yeah like head VE... the better the head flows and the degree'ing of the cams can throw off boost numbers... have any of you thought of that? time the cams for a little more overlap and you will build that extra .5-1 psi

Good idea. Just did some research on VE both in general and for motors, and it looks like even my exhaust (catless/high-flow muff, etc) could cause the loss of .6psi. Thoughts? There are few times when I miss my engineering classes and this is one of them.

I agree with Eric tho, and I'm not crying about it. It could be variance in the gauge or any other little thing. .5psi is nothing to sneeze at, 2psi and I'd be more interested.

[Shawn96VR-4]

Drop the exhaust and find out. I mean, if your not leaking out the IC or the rings, then just accept it I guess.

But, people make the mistake of confusing many small leaks as being acceptable. They result in one big leak.

[hybrdthry911]

if there was a small leak i doubt it would make any boost until the upper rpms, it makes boost immediately sounds like its just normal pressure drop.

[Shawn96VR-4]

Wouldn't the compressor just overspin? I've had holes in my SMIC and still produced the same amount of boost with the typical boost threshold. I just made much less power.

[Captain Moai]

Originally Posted by Shawn96VR-4

Wouldn't the compressor just overspin? I've had holes in my SMIC and still produced the same amount of boost with the typical boost threshold. I just made much less power.

No. Compressor speed is a fixed ratio versus the crank. It's a supercharger. It's physically mated to the crankshaft. It will behave differently than a turbocharger in that regard.

[hybrdthry911]

compressor cant overspin unless the engine does. your turbo is going to keep trying to spin until it pressurizes enough to open the wastegate. i bet you had a bit more lag than usual didnt you though?

[crazybrew609]

lol at eric makin fun of shawn not kinowing crap about superchargers


here ya go shawn

[Shawn96VR-4]

Originally Posted by Moai

No. Compressor speed is a fixed ratio versus the crank. It's a supercharger. It's physically mated to the crankshaft. It will behave differently than a turbocharger in that regard.

I am going to keep shut because I keep confusing the two. So, if any leaks occured, the boost will just be reduced. Correct?

Originally Posted by hybrdthry911

compressor cant overspin unless the engine does. your turbo is going to keep trying to spin until it pressurizes enough to open the wastegate. i bet you had a bit more lag than usual didnt you though?

The compressor should overspin because the flappers aren't open until XPSI is met (Per my EBC). So, it's overspinning, I was outside the compressor map and power took a shit.

I didn't notice the lag actually but I have talked to a lot of people about this as I am against those that think they can tell if they have leaks. I think that's complete bullshit. However, there are soo many ways to modify "lag threshold" (Starting at 2,500RPMS and building more initial load is one way off the top off my head) that I didn't really do much thinking about it. I thought it was a bit diff but that could have been my ass dyno.

[hybrdthry911]

i meant on this supercharger the compressor wouldnt over spin. on your setup the compressor woudl have to spin more to reach the same boost level because of the leak.

[Shawn96VR-4]

Originally Posted by hybrdthry911

i meant on this supercharger the compressor wouldnt over spin. on your setup the compressor woudl have to spin more to reach the same boost level because of the leak.

Yes, you are right. I keep confusing the two.