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New Headers Advice

Thomas_D

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if u want to pass emissions with a blower and cam u need the LS9 cam it does a decent job for factory, using the factory LS cam will work but does drop of quick after bout 6k as u just cant get the exhaust out so it just bottles up and kills power, the LS9 cam with the 230 exhaust lets more out which is why it helps, i had some cheap metal cats that lasted for years without issues boosted and would still be going if i didnt upgrade exhaust not sure what brand they were tho, also mounting cats further back will help them survive the heat (but may not pass tests) e85 will help as it has much lower exhaust temps
I'm tempted to leave the stock cam in it as I'm happy to keep under 6k, even on the track. Also, if I can find a system that can bolt up to the factory exhaust then if I get pinged for emissions I can swap back easily.
Q: Is water/meth still used to reduce IATs on FI applications?
 
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Mattricho

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I believe meth is still used but I would look into interchillers https://fiinterchillers.com/
It uses the cars AC system to super chill the IAT and you don’t need to
1 have a extra tank for water.
2 you don’t need to keep topping up the water.
 

07GTS

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yea bit of a stuff around IMO running meth i only would if i was way up there in power and it needed it and u have to tune for it properly as it changes the AFR, i use ethanol which is better when it ignites and u wont see any knock from it but it just dosnt look as fancy as it dosnt cool the iat's as much
 

Jackel

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You get more power gain (especially on VF1) from a cat back with standard headers and cats, then you do from putting just headers and hi flo cats.

Unless you're going to cam it, i wouldn't be too concerned about EPA issues.
Does that apply to VF2 too? In terms of more power gain from a cat back with standard headers and cats, then from putting just headers and hi flo cats.
 

Mavericks Choice

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Does that apply to VF2 too? In terms of more power gain from a cat back with standard headers and cats, then from putting just headers and hi flo cats.
This is how my VF2 is at present headers+hiflow cats with oem exhaust. Not tuned yet, believe there is no real increase a bit deeper note that's it. Will change mid section next, intake + tune.
 

PeteSS

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Does that apply to VF2 too? In terms of more power gain from a cat back with standard headers and cats, then from putting just headers and hi flo cats.
When you go to the Harrop website, they quote 15kw (flywheel) gain by installing a catback. Headers and hi flo cats are quoted as a 10kw gain.
 

Jackel

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Just got back from my mechanic and had a chat about which full exhaust system to go with.
He said that he strongly recommends Di Fillipo for sound & performance but the issue is that its loud even with the bimodals welded back in.
I know sound is subjective and if its a bit louder than stock than thats fine but dont want it too loud.
Looking at 1 3/4 headers 200 cell cats & 2.5 inch cat back with bimodals.
Sooo how much louder than stock is this thing?
My car is stock apart from custom tune & VCM otr.
Is Harrop quieter?
 

07GTS

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if u want it quiet just adapt the stock rear mufflers onto the DPE system (slightly different rear angles/flange point i think) and it will cut alot of the sound back to basically stock at cruise but still be nice under load and wont affect performance
 

Mavericks Choice

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if u want it quiet just adapt the stock rear mufflers onto the DPE system (slightly different rear angles/flange point i think) and it will cut alot of the sound back to basically stock at cruise but still be nice under load and wont affect performance
This is the route I'll be taking new 2.5" centre section marrying up to the oem bi modals. I have the DPE headers & 200cell cats already installed.
 
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