I'm thinking about doing these two mods on my 991 TTS, but can someone independently confirm that there is actually this much of a gain from the Plenum and Y-pipe for the 991 Turbo S? If this is accurate its an incredible bang for your buck IMO....

 

No chance.

 

If those are the IPD claims then it is with the Cobb Accessport. The IPD plenum and Y pipe do great especially paired with the AP.

-Mitch

 

Check with Sean ( SRM ) . He can help you great deal . Even in fixing you the part with better Quality . I assure you that "

 

this is from their site, the Y pipe says "No Flash"

not sure about the Plenum...

 

There is NO way you can achieve any real HP gains without a flash or an add-on power booster...

Any gains you think you'll get with exhaust / intake related components only, would be very marginal or possibly even negative. You can't do it on these cars or any others that I'm aware of; I'd be very suspect of any claims otherwise.

Upgraded breathing and exhausting requires more fuel, timing, air, etc.. to make more power, which can only be accurately delivered via a re-flash or an add-on power booster.

In general, ECU's are unaware of external changes such as exhaust, intake etc...and cannot to any real degree, compensate for better breathing/ exhausting on their own.

These changes on their own, without software modification, MIGHT give you a few HP at the very, very top of the band, where most people don't live.

I used to hear these things all the time on the Corvette Forums, but I have tested mods like this on the Dyno, without software, and in most cases, have never seen an impactful increase in HP. Most of it is a load of BS, made by a number of unscrupulous vendors out there.

Dyno's can be made to show power increases just by themselves...without doing anything. LOL

If you go this route, I would love to see the before and after same day Dyno runs!

 

Agree 100 percent. ECU need to be reflashed to account for better breathing. And the scrupulous aftermarket exhaust vendors, like Stef from Europipe, say so publicly on their website.

 

100% wrong.

The IPD plenum has been proven to deliver +35 ft lbs and +30 hp to the wheels on a 997.2 Turbo S bone stock. How do i know? Mine was the test car back in 2013 at Cobb SoCal with John Hebblen as the dyno operator. Posted on the 997 Turbo section and IPD website.

Because of the ECU torque limiters the power above 4,500 rpm is nominal.

IPD Mike just bought a 991 Turbo S and developed his Y pipe and just got back from the Cobbs dyno and it made the similar +35/30 delta over bone stock in the mid range no tune.

Together (the plenum and y pipe) will not make 75 hp. But hey will make substantial midrange and paired with a tune will also provide a bit more top end over the tune alone.

 

Just as a FYI the Champion intercoolers hitting the market for the 991 TT and TTS now come with their own Y pipe as part of the kit. So the IPD Y pipe and Champion intercooler kit are either/or mods.

 

If this Mod is done, and then a tune is not done, will the increased of performance last with the stock tune?

 

If you say so...

 

I have the IPD plenum but I got it with a big package of mods so I cannot speak to its independent effect.

What I can say is that the fastest GIAC tuned 991 Turbo S in the country, Karl911's, has it and the fastest 997.2 Turbo S in the country on stock turbos of which I am aware, Longboarder's car, has it.

 

I don't disagree with the gain from the IPD Plenum; I have it as well, but I don't for a second believe it will achieve and gains worth noting all by itself,or even with an x-pipe, no matter

I got my IPD the same as you, with exhaust, headers, intake and a Cobb tune...

 

Never getting the Y pipe as the Champion ICs and Y pipe are going in.

Got a killer deal on very lightly used FVD headers so intend to install those too

 

Blown SRT, do you have Cobb stage 2 OTS or custom tune?