My Crossfire brothers, read carefully and weigh the results for yourselves. Let's start with the day to day review. They are louder than a stock exhaust. At the tailpipe you can't tell a difference but in the car you can. I wouldn't say it's a glorious sound, just a bit louder, with more baritone sounds, more whooshier too. Perhaps because it enhances the intake sound, I still need some more time to find a more precise description. It sounds different, but I wouldn't go so far as to say better. On the dyno I saw a huge increase. I dug out my dyno's from the past and my best corrected numbers were 283 hp and 291 torque with the hp dropping off slightly on the top end. These numbers were in 3rd. gear. My former best 1/4 mile on the dyno was 12.724 at 108.3157 mph.
WHAT'S CHANGED. Needswings cork gaskets, Needswings teflon and thermal coated Y pipe and Needswings downpipes.
Best corrected numbers taken in 4th gear. 311 hp and 298 torque. Best dyno 1/4 mile time 12.352 at 109.069 mph. These numbers are with the cutouts closed. The car was hot for each dyno session. (204º on the dashdaq) Today was 83º and the previous best was in the mid 90's with the humidity the same. (raining) I know it's not the most desirable, scientific, in a perfect world comparison but it's more than anyone has posted that I've seen. Were talking 28 hp and 7 torque people. The cats I took off look perfect to me but who knows, perhaps I had a bad cat? I'll let you judge the numbers with the different conditions and different gears used. Some people claim 3rd gear pulls give better numbers than 1 to 1 pulls (4th on out car) but I really don't know. I feel like I've lost some torque below 2000 rpm. I know I'm all over the place with this post so please forgive me. Tomorrow I have time scheduled on the dyno for open cutouts. Stay tuned.
Summary:
283 hp and 291 torque - 12.724 at 108.3157 mph
311 hp and 298 torque - 12.352 at 109.069 mph

Les

 

Les,
Regarding the exhaust sound - Do you already have the AMG resonator removed?

 

The rest of the exhaust is stock. I still have the resonator and muffler.

Les

 

les do you have a tune on your car? your numbers seem really low for having the dual cai and a c3 pulley. in total stock form and cold weather (50*) i had 321 rwhp and 317 ft/lbs torque. after adding the c3 and a tune i had 341 rwp and 337 ft/lbs. torque. since adding the dual cai and retuning i havent been able to redyno but it seems even more powerful.

im wondering if the heat kills that much power for you. and you picked up almost 3/10 in the quarter but trapped only 1 mph faster?

 

Great review Les I enjoyed reading it, on a side note how accurate are the q/mile times on the dyno machine? 12.3 without a tune is pretty damn quick, if it gets quicker with the cut outs open imagine when you get a tune it'l be an 11 second car for sure.

Goodluck for tomorrow.

 

I have no tune. (yet) The best I've seen at the drag strip is 13 flat at 109 with lots of wheel spin. I just can't get the hang of drag racing. When I got the Code 3 my times got worse. Then the dual CAI and they stayed slow even though the car felt faster. My bag is not drag racing, it's road racing. I have no doubts about how fast the car is, the problem is measuring it in a meaningful way. I have 3 track events in January and I plan on participating in a private drag rental on the 15th. I could an go to a different dyno that reads higher. I was told, but don't know, that 311 on the Mustang is 340 on the other dynos. It's only money, I just might do it. The final number is irrelevant to me, what I'm focused on is the improvement on the same dyno. Let's see what happens tomorrow with the cutouts open and in the month of January. For day to day I'd rather not have the downpipes but I race my car and spend lots of time at redline. The MPH on the dyno are spot on in my experience. The actual time in the 1/4 depends on the driver. To be honest, I wondered if my car was a weakling until I had an instructor that had a GT3 as his daily driver. He thought my car was faster than his. (480 hp I believe) Since then I don't fret over the dyno numbers. Not to mention how much difference you can see from how the car is tied down or how much air pressure is in the tires. I don't know, time will make it all clearer. Tomorrow is with the cutouts open, who knows what the numbers will be. But so far I'm a believer.

Les

 

Great info Les, thanks for sharing. I have heard that the Mustang dyno does not give feel good numbers. The point is the gain after mods on the same machine and it seams there are lots of variables if it is not back to back pulls. As you pointed out your gains are impressive. The #s with the cut outs open will be interesting for sure.

 

I just remembered another thing of interest. You know how the car shifts by itself in manual mode? It doesn't in 4th, it goes to redline and then starts cutting out. Who else has experienced this in a SRT-6? I know the SRT-8's have this paddle hold feature in all gears. (at least with a Predator)

https://www.crossfireforum.org/forum...o-results.html
This thread has the results from a dyno day in St. Louis. Take a look at the numbers on a stingy dyno.
I can't get the link to work for some reason. Search "caa results" and you will find the St. Louis results. The thread is from august 2009.



Les

 

Mine will do that if I let off on the throttle in 4th even if you are getting close to redline. However if you stay on it, it will shift up to 5th. (mine does)

 

fantastic Les, for the "open" dyno, open up the cutout a few miles before the dyno and let the car adapt to the no backpressure, when we "uncork" them at the track the car gets immedietly faster and then continues to improve over the next 2-3 runs, so if you adapt before you get to the dyno it should already be adapted and ready to rock.

 

fwiw les my stock dyno run # were also on a mustang dyno. post tune # were on a dyno dynamics dyno

 

I just got back from the dyno. I had to wait f o r e v e r and when I finally got on the dyno all the employees were leaving. The boss stayed after hours, after all he was the one that told me to return today. Each pull the HP and TQE went up. Because of time constraints we did 2 pulls, a 1/4 run and then a 3rd. pull. I didn't open the cutouts until I arrived at the dyno so no adaptive learning beforehand.

Quick summary of weather corrected numbers/same dyno

Pre downpipes - 283 hp and 291 torque - 12.724 at 108.3157 mph
Downpipes closed - 311 hp and 298 torque - 12.352 at 109.069 mph
Downpipes open - 321.7 hp and 311.7 torque - 12.215 at 110.4506 mph

Les

 

Those are some great improvements, Les. Congrats!! I can't wait to see how much they do for you at the track.

 

I'm astounded if you want to know the truth! Looking at the data it seems on the 1/4 mile run the torque was even higher than what I reported. I'll let everyone decide for themselves from the pictures. 283 to 321 .......

Les

The first picture is the 1/4 mile run. The second has yesterdays best pull with the cutouts closed in blue and todays with the cutouts open in red. The last picture was from the 1/4 mile run.

 

Very impressive numbers. Sounds like the ECU is still adapting. Let us know how the car feels as you put more miles on it. So an inmotion tune and the wavetrac next?

 

The wavetrac is ordered. A tune is in the future too. I'm having an internal debate about switching from the Code 3 to a 178. I'm also looking for a set of lightweight track wheels. I need new tires again.

Les

 

Congrats.... great numbers for a pre-tune. I think these pipes will be in my future. You will be really surprised at the performance increase with the tune. It will be the single best mod you have done to date. As far as the C3 - 178 debate....... You will be looking at what..... 300 - 400 outlay after you sell the C3 and purchase a 178? IMO, I just do not see any advantage to doing that. Especially considering the cost associated with it.

 

great gains Les, I remember talking to my exhaust guy before Rob made these, asking them about cut outs. His thoughts where that running a car pretty much from the manifolds would destory the valves! how true that is Im not sure but I hope for your sake it doesn't apply to our car.

once again congrats!

 

I've never heard of this problem before with any car or engine for that matter. It's better to be over concerned than under concerned about performance changes but in my case, it's done and so far so good. Rob has sold a few of these with no reported issues. After a while running the downpipes I'll give a day to day use review which I imagine is more important to most owners on this forum.

By the way, I found the exhaust leak, one of the cutout gaskets burned through. So I need a new one and a few spares just in case. They appear to be standard long tube header collector gaskets. Also I discovered why my exhaust is crocked. One of the rubber donut hangers at the muffler broke during the installation. My fault, I didn't support the resonator when I disconnected the cats.

I believe the teflon Y pipe is responsible for at least half the gain with the downpipes closed. I can't imagine removing the cats getting the credit for cough cough 38 hp and 10 foot pounds of torque. My dyno operator, from his experience, said most cars see 5 hp from deleting the cats and 10 hp from cutouts. Any way you look at it, Rob's parts produce real gains.

Les

 

Wouldn't it be slick to rig up a couple solenoid motors to open/close the cutouts with a flip of a switch.