Big problem with my power dyno numbers - Page 3 - Lateral-g Forums

mazspeed · #21 08-13-2007, 05:42 PM

Quote:

Originally Posted by ProdigyCustoms

My imediate thought was air cleaner. Also, do not under estimate drivetrain loss. I have seen many cars loose 25% on a RW dyno. So you may already be at 500HP before final tuning, which would not be that bad after all.

I should only have around 10 to 15 percent drivetrain loss. TKO 600 with 373 gears in a 12 bolt with a true trac. We had to downsize the filter by about half from stock.

67SuperSnake · #22 08-13-2007, 05:47 PM

You might try getting cooler air from outside the engine bay, and it may allow a bigger air filter (I used a 12" long, 8 inch round conical) :

Blown353 · #23 08-13-2007, 05:48 PM

I'm also thinking air filter.

Another thing you didn't mention, although I'm sure Jody talked with you about it... what carb hat are you running?

A poor carb hat can absolutely KILL the power, it almost feels like someone cuts the fuel off when you get into the boost.

How closely was the boost watched? Any signs of belt slippage?

What kind of timing numbers are they running (initial, total, when is it all in, vacuum advance or not, and retard amount?)

As far as the discussion on vacuum lines & routing...

The fuel pressure regulator reference goes to the carb hat. You want the pressure in the float bowls to increase at a rate equal to the pressure at the top of the carb & vent tubes, since that's the pressure seen inside the float bowls.

Your timing retard box and everything else should be connected to manifold vacuum (as normal), i.e. below the carb.

mazspeed · #24 08-13-2007, 05:57 PM

Quote:

Originally Posted by Blown353

I'm also thinking air filter.

Another thing you didn't mention, although I'm sure Jody talked with you about it... what carb hat are you running?

A poor carb hat can absolutely KILL the power, it almost feels like someone cuts the fuel off when you get into the boost.

How closely was the boost watched? Any signs of belt slippage?

What kind of timing numbers are they running (initial, total, when is it all in, vacuum advance or not, and retard amount?)

As far as the discussion on vacuum lines & routing...

The fuel pressure regulator reference goes to the carb hat. You want the pressure in the float bowls to increase at a rate equal to the pressure at the top of the carb & vent tubes, since that's the pressure seen inside the float bowls.

Your timing retard box and everything else should be connected to manifold vacuum (as normal), i.e. below the carb.

Ok here is the carb hat. This picture was taken a few months ago, so a lot has changed. I'm not sure of the timing numbers. I was told by a few people that the boost reference should also be on the carb hat, but there was too much fuel going in at WOT. They moved it below the carb and that made everything better. They also blocked off a power valve in the carb as well. I hope this answers some of your question, heheh

mazspeed · #25 08-13-2007, 06:00 PM

Procharger sent us a 1 inch carb hat spacer, because even they said that the quick curve of the carb hat was too much, but CAR had to shave it down to 1/2 inch because of hood clearences.

chrismoe · #26 08-13-2007, 06:16 PM

Mike,

Chris here. I just sent you 2 emails with pictures of my air filter setup.

Hope this helps.

Chris

Blown353 · #27 08-13-2007, 06:17 PM

That hat isn't helping you, unfortunately. It's not the worst hat out there but it's far from the best hats (i.e. CSU, EV, and SDCE.)

In fact, if you were to dyno with that carb hat and 8 EGT's or WBO2's I'd bet you would be very surprised at how much the mixture varied cylinder to cylinder and would probably end up stagger jetting the carb.

A good carb hat makes tuning much easier and will also make more power.

If it was running too rich with the FPR reference off the carb hat, the correct fix is to adjust the fuel pressure and/or tune the carb-- not to move the FPR reference.

Also, what intake are you running? Looks like an RPM Air Gap. A dual plane will work with a blowthrough setup (I ran mine with one for a while) but a good single plane will have better airflow distribution, a Victor Junior is usually the hot ticket for a blowthrough SBC.

MarkM66 · #28 08-13-2007, 06:22 PM

Was that $20k a typo?

69bird · #29 08-13-2007, 06:23 PM

I think your stock cam isn't helping you out either. You want a cam with 112-114 lobe seperation. You might want to see what that cam is.

mazspeed · #30 08-13-2007, 06:25 PM

Quote:

Originally Posted by Blown353

That hat isn't helping you, unfortunately. It's not the worst hat out there but it's far from the best hats (i.e. CSU, EV, and SDCE.)

In fact, if you were to dyno with that carb hat and 8 EGT's or WBO2's I'd bet you would be very surprised at how much the mixture varied cylinder to cylinder and would probably end up stagger jetting the carb.

A good carb hat makes tuning much easier and will also make more power.

If it was running too rich with the FPR reference off the carb hat, the correct fix is to adjust the fuel pressure and/or tune the carb-- not to move the FPR reference.

Also, what intake are you running? Looks like an RPM Air Gap. A dual plane will work with a blowthrough setup (I ran mine with one for a while) but a good single plane will have better airflow distribution, a Victor Junior is usually the hot ticket for a blowthrough SBC.

Is there a better carb hat? Yes I have the air gap. Ill get with CAR about the boost reference location. Only problem is that if it's moved, then we will have to redyno the car. No big deal as it will need to be done anyways. Is the Victor Jr taller? Also, thank you for the advice as well. You guys never cease to amaze me of the knowledge in here.