Aftermarket Exhaust and Boost Levels

[mhoglund]

I used to have a 2006 Corvette. For mods it had Bassani headers with 1 7/8 primaries and highflow cats, Lingenfelter CAI, Magnuson 122HH supercharger, Blower cam, AFR 205 heads, and Magnaflow catback with X pipe. The more freeflowing I made the engine the more I had to overspin the blower to maintain the boost level. If I install headers and a catback onto my 2011 Shelby GT500, will I have to overspin the blower to keep the boost at stock levels?

[SVTboy98]

Yes, you're freeing up back pressure. That means there will be less pressure in the engine, which results in less PSI showing on the gauge. You are not losing power, you're just making the same or more power at less boost. If you want to see XXpsi, then you will need to spin the blower faster on a catless/high flow catted car than you will on a stock catted car.

[mhoglund]

Yes, you're freeing up back pressure. That means there will be less pressure in the engine, which results in less PSI showing on the gauge. You are not losing power, you're just making the same or more power at less boost. If you want to see XXpsi, then you will need to spin the blower faster on a catless/high flow catted car than you will on a stock catted car.

 

 

Thank you for responding. If I install headers with highflow cats and a new catback system with an X pipe, What pulley would I need?

[SVTboy98]

You won't need a pulley, as you'll already be making more power at less boost. If you're looking to up your boost and want to do a pulley swap, you'll need a tune, and I wouldn't send you to anyone other than Justin at VMP. I've been running his 2.65" pulley and tune for a couple years and they're awesome. He now makes a 2.59" pulley, so that's what I'd recommend, but as stated, you will NEED a tune if you swap pulleys.

[dbackg]

Great question.

 

I am consistently hitting 14 psi in 1st & 2nd gear.

 

85 mph in 5th to 4th - i hit 13 psi.

 

The most boost is at lower mph

 

This is my set up and the upgrades I did to the Super Snake in addition to the upgrades completed @ SAI.

 

Current SS setup:

1. FRPP 2.3L TVS M-6066-SGT

2. SVT FRPP 113 MM COLD AIR KIT -M-9603-SVT07

3. SVT FRPP HANDLING PACK - M-2007-FR3SVT

 

with the following added SHELBY SS options: installed @ SAI.

 

1. UPGRADED - Shelby Shifter

2. UPGRADED - REAR matching 6P BAER brakes - RED - installed @ SAI.

3. UPGRADED - SHELBY cooling package.

4. UPGRADED - complete leather interior.

5. UPGRADED - SS leather center console = new SS logo badging

6. UPGRADED - leather shifter boot.

7. UPGRADED - DYNOTECH one-piece aluminum drive shaft.

8. "KR" trunk liner. - installed @ SAI.

9. "KR" rear axle reservoir. - installed @ SAI

10. SHELBY complete pedal set - installed @ SAI.

11. Most updated last generation SS hood. = great NEW redesign! = heat extractor like 68 GT500

 

More upgrades: = approx 650+ RWHP

 

1. NGK plugs.

2. Port match SC & plenum.

3. Throttle body – new FRPP Twin bore 65mm polished - M-9926-CJ65

4. Billet fuel rails - FORE Precision Works – black anodized.

5. Justin's VMP *Big TB* High-Flow Inlet Elbow for TVS Blower.

6. Justin's VMP 2.65 pulley tune upgrade kit - TVSUPGPAK.

7. Exhaust – the Alex Dynatech special. JetHot extreme coating. with high flow cats.

8. Driveshaft Safety Loop - for - DYNOTECH one-piece aluminum drive shaft.

9. Rusty Butt paint treatment.

10. reischeperformance – 170* thermostat

11. R&R rear diff girdle cover. Install FRPP M-4033-G2 low profile diff girdle cover.

12. Rear end traction upgrade:

* Steeda lower billet arms with spherical bearing on axle end and polyurethane bushing on frame end

* adjustible upper

* keep current SS/BMR adjustable panhard.

 

http://www.teamshelb...-vert-upgrades/

[mhoglund]

You won't need a pulley, as you'll already be making more power at less boost. If you're looking to up your boost and want to do a pulley swap, you'll need a tune, and I wouldn't send you to anyone other than Justin at VMP. I've been running his 2.65" pulley and tune for a couple years and they're awesome. He now makes a 2.59" pulley, so that's what I'd recommend, but as stated, you will NEED a tune if you swap pulleys.

 

 

Is the tuning done via mailorder? Or do they put the car on a dyno and tune it there? The drivability tuning should really be done on the street and the high end should be done on the dyno. Is Hp tuners or EFI live used?

[09Troublemaker]

Is the tuning done via mailorder? Or do they put the car on a dyno and tune it there? The drivability tuning should really be done on the street and the high end should be done on the dyno. Is Hp tuners or EFI live used?

 

 

I'd go with the 10% I.W. lower pulley. You'll pick up the lost 1-2 psi and the gain in

tq (50whp) will make you smile

[SVTboy98]

The tuning is done via SCT and Justin can do it remotely. He'll send you a safe tune he has made based off of cars with the mods you have and you can upload it. If you want, you can run that tune and be content that it is safe. That was the option I took until I am done modding. The other option is to drive around, data log and he can adjust the tune from the data logs you send him. You could also go to a shop and he could remotely dyno tune you. There are tons of options, I'd suggest giving him a call and he'll point you in the right direction. vmptuning.com

[Joe GT500]

Looking at the Kooks headers from the shelby catalog...with hi-po cats. NOW, what would be the correct cat-back system?? Wanting to stay with the 3" pipes all the way back.