397/377 SAE with 9" cone and Flowmaster cat-back

[Blue03Cobra]

OK, gang. I couldn't take the Flowmaster negativity and took my car back to the dyno this morning. My car now has 5,600 miles, the 9" open filter from SFPHQ (or JDM) and a '99 Cobra 2-1/2" Flowmaster catback (#17248). Temp was 75-80 degrees and with a misty/muggy environment. STD was very close at 404/384.

Previous results of 367/350 were with 1,200 miles, K&N drop-in (no filter) and I installed the catback the day before without resetting the computer.

Gotta love these numbers on a stock car with filter and mufflers :thumbsup:

So the open filter and motor break-in got me 30 RWHP and 27 RWTq., or the computer hadn't really "learned" the catback (or a combination of the two), the first time around. I would love to see a stock-catted car with 5-6,000 miles, a 9" filter and Magnaflow catback for comparison :coolman:

Later

 

[NastyWS6]

Congrats :thumbsup:

 

[shey love]

What's up Super Mod? I have a similar set up. I had my 03 on the dyno with 950 miles on it and no silencer. 3 pulls. The last one I added a drop in K&N. My rwh was 393.5 and with the K&N it went to 399.1.

Since then I put Flow Masters on like you but no cat back, just plain old muffler swap and a Densecharger 6in CAI. I will have it back on the same dyno on Tuesday for comparison. I will post numbers later next week. Hopefully it's as big a jump as yours.

With your current set up you didn't by chance get an A/F ratio reading did you? Shey

 

[Blue03Cobra]

Originally posted by shey love
With your current set up you didn't by chance get an A/F ratio reading did you? Shey

Take another look at the graph (near the bottom)...;-)

:beer:

 

[Blue03Cobra]

Originally posted by shey love
The last one I added a drop in K&N. My rwh was 393.5 and with the K&N it went to 399.1.

SAE or STD?

 

[stang99]

Your numbers look strong, and, you definitely have a stock looking a/f curve, so you are not making optimised numbers where you are somewhat lean in the midrange and way too rich on the top.

Originally posted by Blue03Cobra
OK, gang. I couldn't take the Flowmaster negativity and took my car back to the dyno this morning. My car now has 5,600 miles, the 9" open filter from SFPHQ (or JDM) and a '99 Cobra 2-1/2" Flowmaster catback (#17248). Temp was 75-80 degrees and with a misty/muggy environment. STD was very close at 404/384.

Previous results of 367/350 were with 1,200 miles, K&N drop-in (no filter) and I installed the catback the day before without resetting the computer.

Gotta love these numbers on a stock car with filter and mufflers :thumbsup:

So the open filter and motor break-in got me 30 RWHP and 27 RWTq., or the computer hadn't really "learned" the catback, the first time around. I would love to see a stock-catted car with 5-6,000 miles, a 9" filter and Magnaflow catback for comparison :coolman:

Later

 

[shey love]

SAE #'s. Stock no silencer 393.5 rwh & 391.2 rwt
K&N 397.7 rwh & 387.8 rwt. Sorry graph showed 399.1 but SAE is 397.7.

Looked at your graph but I don't see any A/F readings. What should I be looking at.

 

[Blue03Cobra]

Originally posted by shey love
Looked at your graph but I don't see any A/F readings. What should I be looking at.

Below the horizontal black line is MPH (diagonal) and A/F (squiggly/descending). Look to the right of the graph for the A/F range. My car starts at around 15:1 and ends up off the scale at 10:1. A/F was very similar to my "stock" pull, seven months ago...

 

[shey love]

Got it. My car has about 3,200 miles on it now. We will see how the changes affect it. Is there a way to adjust the A/F without a custom burned chip.

 

[Blue03Cobra]

Originally posted by shey love
Got it. My car has about 3,200 miles on it now. We will see how the changes affect it. Is there a way to adjust the A/F without a custom burned chip.

Yes with a MAFterburner or the soon-to-be-released Diablo Predator, but I have no experience with either...

 

[shey love]

Thanks man! Maybe they have one and I can come away dialed. We'll see.

 

[RedfireVenom]

Well, it give me hope to know that the HP will increase by that much with more miles on the car. I only got 389.7 RWHP with mods X-pipes, cat-back and CAI. I had 900 miles on my car at that time. I went to the track today for the first time in this car. The track was horrible and two cars spun out because of it. One guy I knew hit the guard rail. I only ran 3 runs and my best time on F1's was 13.61. I'll post more numbers later.

 

[Blue03Cobra]

Originally posted by Redfire2003Cobr
Well, it give me hope to know that the HP will increase by that much with more miles on the car.

I think it was a combination of the miles and the computer adjusting to the catback. If you reset your computer for the exhaust swap, or had significant driving time before the dyno after the swap, I don't know how much your numbers will change...

 

[MalcolmV8]

Blue03Cobra, I was wondering how your car drives in the "real world" with the cat back. Besides WOT is it any different? Do you loose low end torque?

Thanks

 

[davidmax]

NICE #'sI would love to spend your $$$ on a set of Kooks long tubes from JDM.My shop has done less than a dozen 03's so far as we specialize in GM product yet we dyno tune around the corner,we have a Dyno Jet but not set up for chip burning.
I feel break in was 5%,The cat back 15% MAX and the K&N laid down your power.To compliment it with HI flow cats ,long tubes and getting rid of the unneeded pre-cats(you will pass emissions ,actually a better burn)Your good for 30+ ponnies to the pavement.Dave S.

 

[03DOHC]

Looks good Jim.:thumbsup:

 

[08snake]

Jim,
Nice to see these numbers from Flows. If I remember correctly, I dyno'd 426/412 SAE(cool run), during the hot run straight off the street, I saw 414/398, with Flowmaster exhaust and CAI w/chip. Adding the 2.80 pulley and chip re-burn later gave me an additional 37hp and 69ftlbs.

 

[Blue03Cobra]

Originally posted by MalcolmV8
Blue03Cobra, I was wondering how your car drives in the "real world" with the cat back. Besides WOT is it any different? Do you loose low end torque?

Thanks

It'll smoke the tires and go sideways on a 45-50MPH punch in second...don't think Tq. is a problem...

 

[too slow]

Blue03cobra
Your post just helped me make my decision. I had been debating on whether or not to get the Flows but I feel comfortable with the purchase now. I had them on my 2000 GT and absolutely loved the rumble.

I guess that this settles all the debates about the Flowmasters actually losing power on the modular engines... Once again thanks for the posts.

 

[KOTH]

Thanks for sharing. I'm contemplating doing a catback and all this type of info is very useful.