Installation of a replacement exhaust

[Robert YellowVette]

A 1999 6 speed convertible was used. There were baseline runs on a Dynojet.
Max HP 303.7 @ 5500RPM
Max Torque 310.6 @ 4500RPM
0-60 4.97 seconds

The VaraRam was installed and the dyno pulls were repeated.
Max HP 315.6 @5500RPM
Max Torque 321.8 @ 4500RPM
0-60 4.51 seconds

This is on a stationary dynomometer, so there was no "ram" effect.

Can you really accept a gain of 12 hp from a 'ram air' air cleaner while sitting on a static dyno?

The 0-60 test ends at 60 mph, can you really gain a half-second from a 'ram air' air cleaner on a 3200# car?

Pressure of ram air:

Pra = MPH ^2*.0000176

 

[Edmond]

Why do I rarely read about the Vortex air box? If I recall correctly, that was a pretty popular air box a few years ago. So popular, they even designed a version of it for the C4 (it was originally designed for the C5). What happened? I know that it was just under $300 so was that too steep of a price?

 

[DRTH VTR]

What was the correction factor, STD or SAE?

Why is HP measured at 5500 rpm? Isn't that about 1000 rpm low?

The correction factor was the same for both (although there was adjustment for temperature and air pressure), so all that matters to me is the difference between the HP and Torque numbers.

The peak horsepower occurred at 5500RPM. That value was not chosen by the testers. Horsepower is directly related to RPM, so it is not surprising to see the peak at high RPM.

 

[DRTH VTR]

Can you really accept a gain of 12 hp from a 'ram air' air cleaner while sitting on a static dyno?

The 0-60 test ends at 60 mph, can you really gain a half-second from a 'ram air' air cleaner on a 3200# car?

Pressure of ram air:

Pra = MPH ^2*.0000176

I think that there are two things going on. First, the air intake is less restrictive, and the air comes from in front of the car. On the stock intake, it comes from under the car. Could there also be a difference in charge temperature?

This test did not measure the "ram" effect. All I can say is that I picked up 3-4 MPH trap speed in the 1/4 mile. Trap speed is dependent on car weight, which stayed the same, and HP. I am sure that someone could calculate how many HP are needed to pick up 4MPH.

 

[DRTH VTR]

Why do I rarely read about the Vortex air box? If I recall correctly, that was a pretty popular air box a few years ago. So popular, they even designed a version of it for the C4 (it was originally designed for the C5). What happened? I know that it was just under $300 so was that too steep of a price?

Edmond-

I wanted to find the article where one of the magazines compared the Blackwing, the Vortex and the VaraRam. It was a similar test, using the same car and the same dynomometer. The only difference was the induction. All three were improvements over stock, but the VaraRam was a fairly clear winner over the other two. The VaraRam is not cheap, either. It is just shy of $400.

Jim

 

[Heavy Duty]

Thanks DRTH. From the looks of it the intake system did help even on a stationary dyno. I do have a question???with this system is the MAP sensor relocated further upstream? I have read that by placing the MAP further upstream will give a better fuel/air mixture because the air would be cooler than right up next to the engine. With the combination of better air flow and a more truer reading MAP I could see where you could gain a few extra ponies early on.

I use to be a jet engine mech in the Navy. The engine I worked on was the GE T-58 Tubroshaft engine that was used tp power several different helos. We found that by placing an air intake temp sensor near the intake of the engine and feeding the temp into the fuel control we where able to get the engine to generate more HP on less fuel. The other thing we did was to use a fuel/oil heat exchanger to cool the engine oil and heat the fuel up. By heating the fuel we got better atomization of the fuel which resulted in less fuel requirements for the engine to generate the same, or more, HP. The engine only weighed 400 lbs but it was capable of producing 1600+ horses at the out put shaft. That is 4 horses/pound of engine weight.

I know that the LS-6 is not a jet engine. But fuel/air management principles should apply to it as well. Maybe some of the other engine guys could chime in on that subject.

Thanks

H.D.

 

[DRTH VTR]

HD

There is no position change in any of the components. It is just a direct bolt-on air box swap. See my PM.

Jim B.

 

[Heavy Duty]

Thanks. Good info about the VaraRam.


H.D.