H-pipe + tune Pbox results

[TheCPE]

An h-pipe and tune are advertised to be ~40hp combination. So being an analytical type I pulled out my calculator and recalled some physics equations and got started with some test procedures for verifying real world gains from the mods as I put them on.

I saw a good 4-5% increase with just the tune and this morning finally did tests with the h-pipe on.

The 'area under the curve' has definitely increased big time.

A month ago with a DA of 100% (64 degrees, low humidity, 30.02 inches) I ran a 100% stock 60-130 mph of 14.05 seconds.

Today with a bad DA of 94.7% (81 degrees, high humididty, 29.93 inches) in the same location with just a tune and h-pipe I ran 13.12 seconds.

That is a .93 second improvement, or 6.6%. According to several DA calculators the difference between relative horsepower due to the air from my initial run to this one was 4%.

A 6.6% improvement and factoring in that I was 4% in the hole due to air gives an approximate 10% gain which is around the 40hp advertised gains.

Great two mods for some cheap additional power.

Will have to start researching what my next set of mods will be. I want to get below 12s, which I'm pretty sure is possible, especially in fall when I get some nice air.

 

[FastRedPonyCar]

Why not just dyno the car to measure gains?

 

[TheCPE]

Well, a couple of reasons.
A dyno is an excellent tuning device and good at giving you an idea about the performance gains achieved from a modification but it doesn’t provide real world assessments of how much less time or distance does a car need to get to speed X. Some people just want big numbers for bragging rights, and that is fine, but most I am more concerned with the bottom line (real world performance) which is more easily measured using GPS or a drag strips timing system.
It’s also more fun to do my own testing with my GPS box and go back, download the files and analyze the data (you can make some really cool graphs with the Performance Box software) than to watch a dyno pull.
Also, the GPS has an advantage over drag strips in that there are some variables introduced at the drag strip, launch, shift speed, surface prep, etc. Granted the trap is still fairly deterministic despite fluctuations in ET. Doing single gear pulls with a GPS box eliminates all of those driver induced variables so it just makes it simple to see the results.
And then there is the cost. Dyno testing sets of mods costs about $75. So you pretty quickly approach the $500 the Pbox GPS system costs. The difference is as long as the GPS constellation remains in orbit I can test for free in any vehicle I want!
Mostly though, I’m a very analytical type and just find taking my own measurements and analyzing the results fun, and it doesn’t hurt that it gives me real world data to bench-race like crazy with :-D

 

[FastRedPonyCar]

ah. I was under the impression that you wanted to validate the 40hp claim with GPS data.

 

[92hatchlx]

Awesome! So could you feel the difference in the butt dyno with the addition of the h-pipe? Was it the catted or off road one?

 

[92hatchlx]

Or did you do the tune and the h at the same time?

 

[TheCPE]

Well it was a little about verifying the claimed performance gains but I was pretty confident that the tune and h-pipe were legitimately worth around 40hp.

The GPS allowed me to use physics equations (work, power) to get a HP calculation as well as show me the real world time results.

I did the tune and tested and then I added the hpipe and retested.

The tune was a GPS confirmed 5% increase which gives you about 20 more at the wheels. The h-pipe was a GPS confirmed 4% increase from there or about 15hp at the rear wheels.

The tests showed that the combination was around a 35hp gain.

As far as feeling it, I'm not big on butt dynos. For starters you'd have to have a very sensitive butt to feel small gains like that on a 400+hp car anyway. Plus psychologically you want to feel the increase.

However, with both together it was enough for my uncalibrated butt dyno to feel a little difference.

I would like to test the BOSS intake because i have a feeling that one is more peak hp and not so much area under the curve. But i'm not willing to part with $350ish to test it when I don't think it is going to amount to much in real world performance numbers. Plus I don't like the idea of revving to 7,500 on this motor. Ford made significant changes to the BOSS motor to handle the rpm increase.

BTW: I got the lethal o/r h pipe.