[DiMora]

A guy I know just added a 2.3 liter TVS blower to his GT500.

He lives in Denver.

How much boost should he be making?

I figured he should be at 16 or so at seal level, so 13 in Denver (3 PSI loss)...but he's only making 9-10. Ideas?

Second question: ON a GT500 TVS installation, do BOTH nipples on the bypass valve get connected to something?

[08blkgt500]

gt500, denver?

hmmm

yeah, i never heard of psi losses due to altitude... power yes.

[DiMora]

Originally Posted by 08blkgt500 gt500, denver? hmmm yeah, i never heard of psi losses due to altitude... power yes.

Isn't the power loss caused by PSI loss?

Should be about a 3 PSI loss, no?

Sea level ambient air pressure is 14.7 PSI on a standard day.

Let's say the TVS makes 16 PSI boost @ sea level. (Recall that an N/A car would have 14.7 PSI) at sea level...So our total PSI is 30.7 (but we see 16 on the boost gauge)...so the TVS blower is giving us a gain of 109% over ambient PSI.

At 6,000 feet, ambient air pressure is only about 11.78 PSI. 11.78 times 109% equals 12.84 PSI )(plus the ambient of 11.78) so 24.62 PSI in the blower...subtract out the ambient to read the boost gauge (11.78) and we should see 12.84 PSI on the boost gauge or thereabouts, no?

Or am I on crack?

[08blkgt500]

i think it's tuned for whatever boost they want at any altitude. any cars lose power in higher altitude, blown or not blown. i havent floored it in denver/check the psi gauge when the s/c is being used, but im sure it's still the same amount as it was running in cali, just slightly slower to accelerate.

[DiMora]

Epic Boobs.

Wow.

What were we talking about?

Boost. Boobs.

BEWBS.

[08blkgt500]

boobs

[mfj]

skiddamarinkydinkydink, skiddarmareenkidoo....

Your logic is correct. You will actually have less manifold pressure at higher elevation. With a turboset up that's wastegated, you won't lose boost. But on a blower where there is a defined amount of rotor or impeller rotation, you will loose boost...

[EvilBlack]

You definitely loose boost. I have no idea what he should see for boost as I know nothing about a TVS but my KB 2.6 saw about 3 lb drop from sea level to Colorado. The higher the boost, the higher percentage drop at altitude.

[03_StangGuy]

Originally Posted by DiMora Isn't the power loss caused by PSI loss? Should be about a 3 PSI loss, no? Sea level ambient air pressure is 14.7 PSI on a standard day. Let's say the TVS makes 16 PSI boost @ sea level. (Recall that an N/A car would have 14.7 PSI) at sea level...So our total PSI is 30.7 (but we see 16 on the boost gauge)...so the TVS blower is giving us a gain of 109% over ambient PSI. At 6,000 feet, ambient air pressure is only about 11.78 PSI. 11.78 times 109% equals 12.84 PSI )(plus the ambient of 11.78) so 24.62 PSI in the blower...subtract out the ambient to read the boost gauge (11.78) and we should see 12.84 PSI on the boost gauge or thereabouts, no? Or am I on crack?

Dimora you are 100% correct. The less dense air is what causes the power loss. This is why there are correction factors. Doesnt matter if your NA or boosted, there is less air to suck into the engine your gonna have less PSI and power.

Originally Posted by 08blkgt500 i think it's tuned for whatever boost they want at any altitude. any cars lose power in higher altitude, blown or not blown. i havent floored it in denver/check the psi gauge when the s/c is being used, but im sure it's still the same amount as it was running in cali, just slightly slower to accelerate.

The tune is to provide the correct fuel for a given amount of air. A tune cant make up for less dense air. Boost is air pressure plain and simple. if there is less air to compress you will make less boost.