416 Stroker Single Turbo, Cammed...Obnoxiously Loud...Need Advice

[Shake & Bake]

I just got my car back from Nickey after blowing the stock motor. I made the right choice in forging the bottom-end, porting the heads, and adding some lope to the cam (mainly for sound, not performance). Well, it's a single turbo with 3" down pipe, no cats and currently split into two 2.5" Pipes with MRT GFX mufflers.

This was OK with the prior 376 C.I. L99 setup running 550rwhp, but obnoxiously loud with the cammed 416 C.I. stroker pushing 650rwhp. It's bad with minimal throttle.

I'm planning to covert to dual 3" after the downpipe, but I'd like some input on mufflers that cut down on interior drone, have a deep rumble, no rasp, and maybe allow me to start the car in the morning without waking the neighborhood.

Thanks in advance...moderators, sorry please move if in wrong location.

[L99CAMA2011]

Originally Posted by Shake & Bake

I just got my car back from Nickey after blowing the stock motor. I made the right choice in forging the bottom-end, porting the heads, and adding some lope to the cam (mainly for sound, not performance). Well, it's a single turbo with 3" down pipe, no cats and currently split into two 2.5" Pipes with MRT GFX mufflers.

This was OK with the prior 376 C.I. L99 setup running 550rwhp, but obnoxiously loud with the cammed 416 C.I. stroker pushing 650rwhp. It's bad with minimal throttle.

I'm planning to covert to dual 3" after the downpipe, but I'd like some input on mufflers that cut down on interior drone, have a deep rumble, no rasp, and maybe allow me to start the car in the morning without waking the neighborhood.

Thanks in advance...moderators, sorry please move if in wrong location.

Aside from sound how's the performance? Any quarter mile times?

[Shake & Bake]

Originally Posted by L99CAMA2011

Aside from sound how's the performance? Any quarter mile times?

Performance is insane. I wanted the car to be scary and box checked. It's night and day difference from the prior configuration. This motor is built to handle 1000rwhp, but my stock 6L80E transmission is the limiting factor for now. No track time since it's too cold to get any traction and I'm still on my Nitto Motivo's. M/T's are in the garage waiting for spring.

[SSE 4 2SS]

Here is a few videos of my car at full song and at idle on the dyno... You know a lot is going on but it's very sedate at idle or when just driving around.

I run dual 3.5 inch pipes with no cats and magna flow mufflers... 3.5 in and out... 417 stroker, Twin 76 mm turbos, 3.5 inch down pipes, waste gates dump to atmosphere... The following videos are from dyno time, at idle, and at full song... It's the best I can do for now... The last pull is at 27 or 28 lbs of boost and 1993 RWHP.... Yes this is with the full exhaust system.

[Shake & Bake]

Originally Posted by SSE 4 2SS

Here is a few videos of my car at full song and at idle on the dyno... You know a lot is going on but it's very sedate at idle or when just driving around.

I run dual 3.5 inch pipes with no cats and magna flow mufflers... 3.5 in and out... 417 stroker, Twin 76 mm turbos, 3.5 inch down pipes, waste gates dump to atmosphere... The following videos are from dyno time, at idle, and at full song... It's the best I can do for now... The last pull is at 27 or 28 lbs of boost and 1993 RWHP.... Yes this is with the full exhaust system.

Wow...that seems pretty quiet for such a monster. Don't see how you put the power down without those tie down straps. I'd post my video but it's misleading since it's hard to know how to set the volume to match the in-person experience until you're there. Guess I should have set it to max so I would have been better prepared when I picked the car up.

I love the moderately loud chop at idle, but not the bone jarring resonance at around 2krpm.

[SSE 4 2SS]

Originally Posted by Shake & Bake

Wow...that seems pretty quiet for such a monster. Don't see how you put the power down without those tie down straps. I'd post my video but it's misleading since it's hard to know how to set the volume to match the in-person experience until you're there. Guess I should have set it to max so I would have been better prepared when I picked the car up.

I love the moderately loud chop at idle, but not the bone jarring resonance at around 2krpm.

We run ProEFI for our engine management system, and the traction control feature in it is second to none... It'll dump timing, dump boost, or whatever it needs to keep the front and rear tires spinning at the same speed.... Before ProEFI, I spun my tires in excess of 190 mph in 5th gear on the factory Pirellis... that was mind blowing... Spray hit and tires gave up... Now we have bigger turbos, which come on more gradually, no nitrous, and the traction control... along with bigger stickier tires...

[1KillerSS]

+1 for magnaflow. its civil at idle and screams at WOT. Mine is a 3 inch also.

here is a short idle clip



This is a dyno run, the only reason I posted it was that, I dont have any good sound Videos of me at WOT.

[bayarea408]

you blew the motor at 550 whp?

Did you turn it up? lack fuel?

[Shake & Bake]

Originally Posted by bayarea408

you blew the motor at 550 whp?

Did you turn it up? lack fuel?

I pulled a stupid and ran with HFC's. The driver side cat melted, shot shrapnel through my turbo which got stuck in one of the waste gates, and the back pressure appears to have caused hydrolock. Three of the connecting rods were bent and metal shavings were found in the oil pan and pickup.

Lesson learned...cats and boost don't mix well.

[KaBoom1701]

Originally Posted by Shake & Bake

I pulled a stupid and ran with HFC's. The driver side cat melted, shot shrapnel through my turbo which got stuck in one of the waste gates, and the back pressure appears to have caused hydrolock. Three of the connecting rods were bent and metal shavings were found in the oil pan and pickup.

Lesson learned...cats and boost don't mix well.

I was told you can run cats boosted but you need to make sure your tune is not too lean. Running too lean puts excess fuel on the cats and with the added boost temp that what's melts the cats.....


Or so I've heard.

[Shake & Bake]

Originally Posted by KaBoom1701

I was told you can run cats boosted but you need to make sure your tune is not too lean. Running too lean puts excess fuel on the cats and with the added boost temp that what's melts the cats.....


Or so I've heard.

AFR was supposedly around 12. Not sure how running lean would put more fuel in the cats but the exhaust will certainly be hotter and can cause them to melt. I damaged two passenger side cats (core separated from outer casing) before the driver side cat melted.

The risk of a clogged cat or shrapnel shooting through a turbo at WOT is too high for me going forward.

[Shake & Bake]

Originally Posted by 1KillerSS

+1 for magnaflow. its civil at idle and screams at WOT. Mine is a 3 inch also.

here is a short idle clip



This is a dyno run, the only reason I posted it was that, I dont have any good sound Videos of me at WOT.

Sounds good...my added problem is all of the convertible bracing in the rear that limits my options. Guess I'll try different muffler options until I get it dialed in.

[Bildo]

Man I hear you about the HFCs, I had a pair of SLP HFCs running a 150 shot RICH and it shot the elements out of both, knocked the passenger side element completely loose within the cat it self and I had to fight the the drivers side element which was completely jammed into x pipe after it shot out of the cat..... PITA.