924 RWHP TT 2019

[pro 5.0]

Yep couldnt agree more. Funny i started on the Denso's also (Lund's suggestion) and i switched to 6510's and the car runs better. I think mine are gapped at 22 or so. Im also on .82 housings.

Does your exhaust have an H or X mid pipe? Mine had an X but i eliminated it when i built the 3" exhaust. It doesnt sound as nice as it did with the X, but it no longer floats the valves so i plan to keep it out for now.

There is no need to run the plug gap at .018 but I went to the extreme to eliminate the possibility of spark blow out, I've never found plug gap to have any bearing on how the car runs otherwise. I have the Corsa double X pipe which should create more exhaust velocity than an H pipe, I like the exhaust note and there is no drone when you go WOT the sound of those wastegate dumps can't be beat. I highly doubt that putting the X pipe back in would create a valve float issue, however if it's working good now leave well enough alone lol.

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[gimmie11s]

There is no need to run the plug gap at .018 but I went to the extreme to eliminate the possibility of spark blow out, I've never found plug gap to have any bearing on how the car runs otherwise. I have the Corsa double X pipe which should create more exhaust velocity than an H pipe, I like the exhaust note and there is no drone when you go WOT the sound of those wastegate dumps can't be beat. I highly doubt that putting the X pipe back in would create a valve float issue, however if it's working good now leave well enough alone lol.

Definitely.

Remove your X’s and replace with straight 3” pipe just to eliminate that before upgrading turbos or valve springs.

Would be a cheap experiment worth trying

 

[pro 5.0]

Definitely.

Remove your X’s and replace with straight 3” pipe just to eliminate that before upgrading turbos or valve springs.

Would be a cheap experiment worth trying

I've reached a fork in the road so to speak the car is making decent power @ 12 psi, if I alleviate the back pressure issue it will allow me to run more boost and that will tax the stock engine even more forcing me to build the short block. Probably best to leave well enough alone as you push more power it's just a snowball affect lol.

 

[sigintel]

8k on 13 psi with 0 float.

!
Hmmm PAC springs available?
Whos changed springs w heads in?
Oil soak the cylinder and hold the valves shut w compressed air and crank locked?

The valves opening can be from compression waves/shockwaves bouncing back from dynamic constrictions/sonic constrictions or even hard bends in piping leading to the turbine inlet.
When a compression wave (like when exhaust valve first opens) hits a bend like turbine inlet, it creates a local compression of higher pressure than the incoming compression wave. Just like in traffic, someone ahead hits the breaks, and a wave of break checking moves backwards against flow.
If exhaust bypass valve is undersized, it still requires a significant pressure gradient across the valve restriction to achieve a certain flow. The larger the bypass/exhaust dump the better this curve would be.

I am thinkn a slightly less restrictive A/R and/or slightly larger turbine/turbine housing for road course work. Certainly risks much slower spooling, but on the street could add a spooler/antilag if really cared.

 

[gimmie11s]

!
Hmmm PAC springs available?
Whos changed springs w heads in?
Oil soak the cylinder and hold the valves shut w compressed air and crank locked?

The valves opening can be from compression waves/shockwaves bouncing back from dynamic constrictions/sonic constrictions or even hard bends in piping leading to the turbine inlet.
When a compression wave (like when exhaust valve first opens) hits a bend like turbine inlet, it creates a local compression of higher pressure than the incoming compression wave. Just like in traffic, someone ahead hits the breaks, and a wave of break checking moves backwards against flow.
If exhaust bypass valve is undersized, it still requires a significant pressure gradient across the valve restriction to achieve a certain flow. The larger the bypass/exhaust dump the better this curve would be.

I am thinkn a slightly less restrictive A/R and/or slightly larger turbine/turbine housing for road course work. Certainly risks much slower spooling, but on the street could add a spooler/antilag if really cared.

All interesting points. These coyotes REALLY move a lot of exhaust air and as such must have free flowing exhaust once you go turbo. It's always been a big problem since 2011 with single turbo guys who select a hot side that's too small.

The Twin guys have set ups that are a little more forgiving due to the exhaust moving through two turbos instead of collecting and trying to be forced through one hot side of one turbo.

If i had endless funds, I'd buy 5-10 different twin turbo sized set ups and try them all.

When i put together my kit, i was acutally looking for a turbo with an .82 hot side along with a minimum of a 66mm wheel (knowing how much the exhaust needs to move on these cars). I wanted to keep the compressor small and would have actually liked to stay around 60mm because i will never, ever use what twin 67's can belt out. I probbly wouldnt be able to max out twin 60mm compressors.

Keeping he compressor smaller would aid in spool up while still allowing enough exhaust to move out the hot side assuming a 66mm turbine.

 

[pro 5.0]

Hmmm PAC springs available?

I don't believe the PAC 1234X springs will work on a Gen 3 due to the installed height, however MPR has a set of springs that will work. Seat pressure is important on these VCT engines as you must be careful not to put too strong of a spring in as it will affect the phasers. 95 lbs on the seat should do the job.

 

[supertuner700]

Can you guys post exhaust sound clips of your twin turbo cars please? I have stock active exhaust with resonator delete and loud valve dumps and it’s too quite at idle and lower rpm until the dumps open and it sounds like a plane lands next to me...so I need other options and was leaning towards the stainless works redline active series

 

[pro 5.0]

Can you guys post exhaust sound clips of your twin turbo cars please? I have stock active exhaust with resonator delete and loud valve dumps and it’s too quite at idle and lower rpm until the dumps open and it sounds like a plane lands next to me...so I need other options and was leaning towards the stainless works redline active series

The waste gates open to atmosphere will not affect idle or cruise exhaust note, you will need to change your cat back to get the results you want. I have the Corsa active valve exhaust on mine it's very aggressive and has no drone.

 

[Excel]

Eventually we will see the I broke my shit thread,I thought stock was safe to 1000+HP

 

[pro 5.0]

Eventually we will see the I broke my shit thread,I thought stock was safe to 1000+HP

I'm not worried about what could happen if it happens I will deal with it, there are many other stock engine cars pushing them a lot harder than me thanks for your concern.

 

[supertuner700]

The waste gates open to atmosphere will not affect idle or cruise exhaust note, you will need to change your cat back to get the results you want. I have the Corsa active valve exhaust on mine it's very aggressive and has no drone.

I have exhaust dumps that open under boost called loud valves and wastegate opens to atmosphere

 

[pro 5.0]

I have exhaust dumps that open under boost called loud valves and wastegate opens to atmosphere

Neither of those will affect cruise or idle exhaust note, so what's your point ?

 

[supertuner700]

Neither of those will affect cruise or idle exhaust note, so what's your point ?

No point I want a sound clip

 

[pro 5.0]

Search YouTube.

 

[supertuner700]

It is back pressure. What is your exhaust set up? Mine floated the valves above 10 psi when I had the stock cat back.

I installed a custom 3” all the way from turbos to tips with straight through mufflers and now it pulls absolutely clean as can be all the way to 8k on 13 psi with 0 float.

The valve spring installed height on the Gen 3 cylinder head is almost a 1/4 inch taller on our motors vs Gen 2.

This is why we float the valves at lower boost.

Short term answer open flowing exhaust.

Would you mind posting an exhaust clip from your car?

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