Whipple Stage II + 1 7/8 Long Tube Headers

[Whipple Bullitt]

Am debating whether it is worth the cost/added noise for any extra performance gains. Have done some research into whether or not a new tune is required. Responses have been that my Whipple tune will more than handle it. Has me second-guessing, whether or not any performance increases will be worth the extra cost/noise. Any input from people who have went this route would be appreciated.
Other exhaust mods includes a Steeda H pipe, Mach one exhaust set up.

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[robvas]

The big reason to do it is to get rid of the stock cats...

 

[Whipple Bullitt]

Will be doing the catted version.
But yes I understand the getting rid of the STOCK cats.

 

[RiotfunK]

I'm adding Stainless Power headers with Gesi 450 cats. my shop recommends a tune. As did Wengerd. Stock motor probs ok without tune. But with the boost. I'd have it tuned.

 

[stang17]

Will be doing the catted version.
But yes I understand the getting rid of the STOCK cats.

Make sure you verify which GESI cats are coming with the headers. At a minimum you will want the GESI G sport Series UHP Gen 2. I know Kooks sells them rebranded as their HO Green Cats.

I've had the stock cats as well as regular Kooks non green cats fail rather quickly running the supplied whipple tune. Ran catless for a while but the rasp was terrible above 4,000 rpm and 93 octane fumes in winter months would fumigate anything in trunk.

I bit the financial bullet a few years back and got HO Green Cats and have been trouble free running both 93 and e85. Just be sure to have COT protection turned on in tune and dont use any 2 step, no lift shift, or pop/bang tune if you want them to last.

Fwiw I made 786 sae without them and 819 std with them on another dyno, which just so happens to correct back to 786 sae. Literally no difference in power with the HO GESI at my particular power level. They do significantly cut down on the raspiness and 93 fumes, although not 100% elimination

 

[Whipple Bullitt]

Thanks for the very useful info. I’ve adjusted my order regarding cats, making arrangements for some Dyno time and a tune.
Hearing of people gaining as much as 60 RWHP with a custom tune over the stock Whipple tune

 

[stang17]

If running 93 octane, I'd suggest staying in the mid 600 range. Its only a matter of time until you come across a bad tank of gas and any detonation/pre ignition at cylinder pressure levels to achieve 700+ hp are not very forgiving to the stock pistons and stock ring gap.

E85 completely different story due to the extra cooling effect. I'd feel comfortable running to at least 850 whp on pump e85. Anything beyond that, its best to run a dedicated race fuel out of the can where the non ethanol component is race gas and not hotdog water 84 octane.

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