Another Gen 5 whipple thread .

[TX-Ripper]

I’m not sure there is much difference from 2.5 to 3.0” vs removing a real choke point

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[olaosunt]

I know any resonator is a restriction compared to a delete but hate loud and raspy with the later .

Magnaflow has 3 inch cat back that comes with its own resonator it looks like but.... almost $2K plus $800 for the actuators
https://www.americanmuscle.com/magnaflow-street-catback-exhaust-2018-gt.html

 

[Andy13186]

Just FYI I tried to put in a magnaflow 12599 x pipe muffler as a resonator but it is too big, magnaflow specs arent accurate on it. Its too big even after I modified it to be thinner to hopefully not hang as low, would have required a good bit of fabrication or exhaust modification and hang low.

 

[engineermike]

@olaosunt thats the cat back I have. The resonator inlets and outlets are 2.5” and it necks down to 2.25” for the factory connect.

 

[olaosunt]

@olaosunt thats the cat back I have. The resonator inlets and outlets are 2.5” and it necks down to 2.25” for the factory connect.

so it’s not 3 inch all the way ?
what part of the factory exhaust does it connect to ?
The cats ?

 

[engineermike]

so it’s not 3 inch all the way ?
what part of the factory exhaust does it connect to ?
The cats ?

It starts at 2.25” at the factory connection just upstream of the resonator, then necks up to 2.5” and stays 2.5” until after the resonator. I was a little disappointed TBH.

 

[olaosunt]

Engine and clutches in transmission broken In (I think ) after 400 miles .

Got logs of WOT pulls after first oil change (driven )
Logs look good . Initially thought I had slip on one pull but looks like wheel spin on the logs .

Also picked up cat less pipes from forum member .
Getting close to to making first pass this year but I may put it on the dyno first .

 

[SolarFlare]

Sweet brother! cant wait to see that!

 

[olaosunt]

I got a couple of shake down passes last week .
I was hoping to have the cats off before but the v band clamps my guy ordered did not arrive in time ... so I decided to run with the cats anyway ... kind of rolling the dice on melting them but very few days left this year(closed this week ) to run and yet to make a pass this year .

PBD second gear leave tune /3.75 upper .
First pass :
I was not sure how high to stall with stock converter so I left like I do with the first gear leave tune @1700.
Tires spun and had to pedal a bit , car felt strong but it was short shifting @7k .
10.4@143 - 1.7x 60 ft so kind of disappointed but it was hot and humid with DA close to 4000. Active exhaust also stock in normal and cats probably cost 4-5 mph so trap is not that bad . it’s similar to what car trapped 2 years ago with old motor with 3.25 six rib pulley(equivalent boost )no cats in 500 DA .

Second pass .Dropped tire pressure a bit and left a little higher . 60 was a little better at 1.6X and ran quicker -10.1@143 still shifting at 7K

Third pass
went back to first gear leave but just blew off tires, shiort shifted 1-2 and got out of shape so I lifted .

Car felt strong on first 2 passes although they flagged me after the first pass for blowing smoke .
There was nothing in my tall pipe and logs looked really good so i assume it was just oil left after motor failed .
No smoke on second pass .
I noticed it did not run as straight as I remember so may be effect of losing the front sway bar .

Got revised tune and cats are now off . They looked good when they came off . System. is modular so I can go back and forth easily.
Car sounds so much better now (still not loud ) and my butt dyno tells me it picked up quite a bit of torque .

 

[SolarFlare]

Solid initial passes, O.

 

[4sdvenom]

Nice passes for just getting back into the car after the changes that were made. Get things dialed in with the launch and 60 foot and you're well into the single digits man!

Ken

 

[Det_Riot]

Not bad at all! FWIW, nomatter what exhaust mode you're in, they fully open over 3k RPM at WOT

 

[olaosunt]

I know the active exhaust does that on the GT350 but i never noticed it on this car .

We checked all the wiring /plugs and it looks like it is the actuator on the passengers side that’s bad . it seems the valve on that side is the one that gets stuck at times then every thing stops working .

I am going to see if i can get it fixed under the power train warranty and if not i will order a new actuator.

We disconnected the active exhaust and found out to my delight when you do that it stays in race mode !

 

[olaosunt]

I got a couple of shake down passes last week .
I was hoping to have the cats off before but the v band clamps my guy ordered did not arrive in time ... so I decided to run with the cats anyway ... kind of rolling the dice on melting them but very few days left this year(closed this week ) to run and yet to make a pass this year .

PBD second gear leave tune /3.75 upper .
First pass :
I was not sure how high to stall with stock converter so I left like I do with the first gear leave tune @1700.
Tires spun and had to pedal a bit , car felt strong but it was short shifting @7k .
10.4@143 - 1.7x 60 ft so kind of disappointed but it was hot and humid with DA close to 4000. Active exhaust also stock in normal and cats probably cost 4-5 mph so trap is not that bad . it’s similar to what car trapped 2 years ago with old motor with 3.25 six rib pulley(equivalent boost )no cats in 500 DA .

Second pass .Dropped tire pressure a bit and left a little higher . 60 was a little better at 1.6X and ran quicker -10.1@143 still shifting at 7K

Third pass
went back to first gear leave but just blew off tires, shiort shifted 1-2 and got out of shape so I lifted .

Car felt strong on first 2 passes although they flagged me after the first pass for blowing smoke .
There was nothing in my tall pipe and logs looked really good so i assume it was just oil left after motor failed .
No smoke on second pass .
I noticed it did not run as straight as I remember so may be effect of losing the front sway bar .

Got revised tune and cats are now off . They looked good when they came off . System. is modular so I can go back and forth easily.
Car sounds so much better now (still not loud ) and my butt dyno tells me it picked up quite a bit of torque .

updated post with time slips (nothing to
write home about )
I thought at first it was not too loud with active exhaust disconnected (permanently in race ) but it gets tiring and has a drone at times

I now think it sounded perfect in normal mode (nice and smooth/no drone ) so definitely going to replace that actuator with or without warranty (it’s only $145 and it takes 3 mins to replace ).
I have been looking over the logs of the last passes and not only was it short shifting at 7K , it looks like it may be rich —Lambda is perfect at 0.77-78 but STFT are pulling 12-15%.. The timing also gets ramped by rpm . On the street logs I don’t see 21* until 7500... and considering it‘s shifting at 7000 rpm , its leaving power on the table.

No logs yet of new tune .. but going to ask Rob to make sure those concerns are addressed along with shift points .
If not, I may have to consider Lund (he tunes my other 3 S550’s anyway ) .
Still on ID 1050X ‘s and looks like I have enough injector but will be swapping to the ID1300’s when I pulley down to the 3.375 pulley .
Pumps are still DW400’s in the DwX2 hat but I have a Fore hat x 3 274’s/FC3 controller ready to go .


On a side note(will start a new build thread) decided to follow in my ”mentor‘s” @80FoxCoupe foot steps and
started finding homes for all those “spare “ motors and transmissions (well the “spares to spares“)...

Especially since it it looks like I finally found a really good shop ... so may be I will not be needing all that spare stuff .
Also listed the other 3 S550’s(including the GT 350) ... no real bites , so happy to keep them to be honest rather than give them away .
This is one going to be all motor (at least at first ).

Stock Gen 3 I picked up a while back (i was going to build it , but OEM motor I thought I would use for this swap did not cooperate so building that instead ) . 10r80 I just swapped out .
Looking for buyer for the 302/Terminator X/Built C4 in it now . It sounds mean as hell but... damn it’s slow

View attachment 609672

 

[kevinvan6000]

Kinda late, but I run that same Jones resonator on my car. It tones down the volume a fair bit for daily driving. Clip of my car if you want to see what it sounds like. Im running catless headers, the jones resonator into an MRBP street cat back. -

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