[sprint200]

Many may know that my car is extensively modified. Those mods, however, had been limited to the suspension with the exception of a VMP tune and muffler delete.

Early last month I installed the C&L intake along with VMP's stock appearance 2.65" pulley and 91 octane tune. The SOTP index factor was big. But as everyone is aware, it loses a bit of "oomph" as it gets hot. Shortly after installing the parts we dyno'd the car (sorry, no stock baseline). The results were pretty good, knowing that the numbers are all relative to multiple factors down to and even including on which version of software the runs are being viewed.

The predictable thing that we noticed was the drop in power from the first run to the last.

Here's a shot of teh graphs from that dyno session.


Shot at 2008-04-23

Then PSE Superchargers took the blower and ported it (no stage 1 or stage 2 stuff....they only port one way.....complete). The car was back together just in time to load it up and take it to the Lone Star Round Up down in College Station. Two days on the track told me that the power loss from heat soak were not as pronounced. But I had to wait due to work load and weather before getting the car back to the dyno.

Here are those results


Shot at 2008-04-23

Note that the second run produced more power than the first and the drop off on the third pull is very slight. There were only 7 to 8 minutes between runs during both the before and after sesions with NO other cooling aids besides a couple of fans on the nose. Both sesions were with the hood closed and the temperatures & barometric pressures were almost identical.

Also, there were NO other modifications besides the porting. NO change in the tune, pulley, h/e........etc.

I have a spread sheet showing the intake temperatures and the charge air temp's somewhere and can't find it right now, but I'll post that when I find it. But the bottom line was that the charge air temp's dropped by an average of 13 degrees after the port. IIRC they never got above 112 deg F even on the last pull.

I've got all the digital files from the runs, but I'm not "tech-savvy" enough to know what to do with them.

I'll still change out the s/c heat exchanger for those August afternoons here in Oklahoma, but it's not nearly the issue it was before the port.

Thanks PSE and Ed! Job well done.

[littlejohn]

Your A/F ratio seems lean, especially below 3500 rpm. Most guys are saying to run 11.5 - 12.0 with the extra boost. Maybe I'm missing something. Also, run #4 shows a much richer A/F, yet makes just as much power. What happened there? I'm only wondering as I am really interested in porting mine, and am just wondering about these possible inconsistencies on the dyno graphs.

[Fastbackman]

Good info Jeff. I'd love to bring mine to Ed for porting and dyno runs. Somehow I have to convince the wife that it needs to be faster.

[sprint200]

littlejohn, on Apr 25 2008, 01:13 AM, said:

Your A/F ratio seems lean, especially below 3500 rpm. Most guys are saying to run 11.5 - 12.0 with the extra boost. Maybe I'm missing something. Also, run #4 shows a much richer A/F, yet makes just as much power. What happened there? I'm only wondering as I am really interested in porting mine, and am just wondering about these possible inconsistencies on the dyno graphs.

I should have mentioned that the a/f on these dyno runs were measured by a tail pipe sniffer. I was told that the difference usually works out to about 0.5.

We did run it on a Mustang dynamometer earlier and got very good a/f ratios with the sensor before the cat's. But as everyone knows, the Mustang numbers are not comparable to what most people use so we went to another dyno.

Run #4 was the first "after" run and the engine was not up to operating temperatures. Accounting for the tail pipe sensor it was probably way too rich.

Fastbackman,

I've got your problem solved. Just tell your wife that a Cowboy can't be FASTER than a Sooner........

[Fastbackman]

sprint200, on Apr 25 2008, 08:00 AM, said:

I should have mentioned that the a/f on these dyno runs were measured by a tail pipe sniffer. I was told that the difference usually works out to about 0.5.

We did run it on a Mustang dynamometer earlier and got very good a/f ratios with the sensor before the cat's. But as everyone knows, the Mustang numbers are not comparable to what most people use so we went to another dyno.

Run #4 was the first "after" run and the engine was not up to operating temperatures. Accounting for the tail pipe sensor it was probably way too rich.

Fastbackman,

I've got your problem solved. Just tell your wife that a Cowboy can't be FASTER than a Sooner........

That's funny stuff Jeff. I only wish it were that easy for me. She's a tough sell when it comes to making this car faster. I need a big rathole of cash but right now my secret assets sets at $20.