Staged testing vs performance parts
 

Here's Superformance 2040 with Roush 427R-095 data that I'm reasonably certain is accurate after looking at things upside down, backwards and inside out. The actual test runs were for acceleration in gears 1 thru 4, but I used 3rd gear for a solid power reference. I grouped the changes I've made to my car from original new as delivered Stage 1, then Stage 2 then Stage 3.

The most noticeable changes in power came from the Pro-Systems carb Stage 2 and Buckshot Racefab side pipes Stage 3 which required going up an additional 3 jet sizes. Subtle changes in power came from 2" primary headers and larger surface area air cleaner. The fuel line change in stage 3 had no change in performance in 1st, 2nd or 3rd gear under load, though seems to prevent lean stumble at top of 4th gear around 135 to 140 mph when using 27" tall rear tires. The aluminum flywheel took away drag race acceleration at shift points because of rotating mass inertia loss as the next gear hit, but added for a street driving snappier rolling punch and seems to aid in having the tires hook better in 1st and 2nd gear over slightly uneven road conditions. The Aluminum flywheel did nothing for quicker shifts, and had no value to power gain or loss under load out of gear shift range.

http://www.clubcobra.com/photopost/d...erformance.JPG

Here's a Dynojet, wheel HP pull for another perspective of my "Stage 3", current set up.
475.3 wheel HP, 459.3 Tourque
http://www.clubcobra.com/photopost/d...3_wheel_HP.JPG

0-100 in 6.28. Gotta love those MTs...As much as the other mods helped the performance, I have to think that the drag radials replacing the BFG stones were the largest booster to the improvements. A good and well dialed-in carb is worth 20HP and we all know what the effect on bigger sidepipes can do for these cars. Interesting data, Greg...thanks for posting!

-Dean #747

How do those new pipes sound? Any chance of posting a sound bite?

Greg,
Great stuff!
Do you have a PN for the S&B cleaner and Cobra oval? How did you get it under the hood, lowered bottom section? I have the K&N oval but it's only 1" or maybe 1 1/2" deep. Based on posts calculating air need, I think I'm fine, but always shopping for more.
I see (in your gallery) you're not using a phenolic spacer under the carb - ever had vapor lock? I have a spacer and I've still had mine choke and gasp from time to time.
Thanks again, this is really helpful info!

If anybody in my area with a Superformance original set up 427R wanted to put my Mickey Thompson ET street drag radials on their car for a G-tech pass in the same test area I'd be happy to help. The results would be interesting.


Here's a link to a drag strip pass with sound
drag video with sound


The air cleaner is from http://www.cobranda.com/sbovairfielt.html . The intake assembly is the cheaper maid in Taiwan type which actually has a slight drop on the pressed sheet metal base. The top is the usual cast aluminum with the Cobra oval look. I've never had any vapor lock or had a starting problem.