Supercharged SRT with VEC 2, check out the dyno results...

[Sleeper]

I wanted to get more power out of my supercharged car. Subsequent mods have included Corsa track exhaust, Fidanza flywheel, larger injectors, and a VEC 2 system. Addressing both drivability and power issues required several hours of dyno tuning, so this path may not be everyone's cup of tea.

The tuning was done at Performance by Joe, here in St. Louis, by the owner Joe Donovan. Joe is well known by many on this board for high performance tuning, and has extensive experience with the VEC 2.

I know many of Joe's customers (and their cars), so I was expecting good results. But not this good:

726 rwhp, and

687 rwtq

This is with the standard pulley, and no head/cam work. It really pulls like a beast through the rev range, and as you can guess, I'm very happy with the tuning done by Joe Donovan!

Thanks Joe for your awesome work,

Thomas DeCosta

 

[STUGOTS]

SWEET.

Paxton S/C??

how many pounds? 7.5?

 

[Dave T (BADVENM)]

What are the numbers in your sig? either set of numbers is quite impressive.

 

[Raheel]

What are the numbers in your sig? either set of numbers is quite impressive.

Add 15% to the rwhp/rwtq numbers to get the numbers in the signature.

Raheel

 

[Dave T (BADVENM)]

Oh, stupid me. Thanks for the clerification. Its all in the tuner how high these numbers can get. I'd love to get something close to those should I upgrade to a Paxton on my SRT Ram.

 

[STUGOTS]

Oh, stupid me. Thanks for the clerification.

Actually I was going to ask too lol

guess were just not used to it most people put RW in their sigs

 

[BigCarrot]

That's just about what mine made, but I still had the Split Second box. I'm sure yours runs a little smoother. I had planned to do a Vec 2 if I kept the car.

 

[STUGOTS]

That's just about what mine made, but I still had the Split Second box. I'm sure yours runs a little smoother. I had planned to do a Vec 2 if I kept the car.

whats the split second box?

 

[BigCarrot]

It's what comes with the kit from Paxton. Works great when you just bolt it on to a stock car, but if you want to do much tuning, you need something better like the Vec.

 

[rbarta]

Do you know what the #s were before the tuning?

 

[STUGOTS]

Thanks Carrot, I never heard anyone mention it before.

 

[Sleeper]

STUGOTS Yes, it's a Paxton. Highest boost is 7.4 lbs.

The Split Second unit adjusts timing and pulse width:

http://www.splitsec.com/index.html

Dave T Thanks

 

[Sleeper]

Do you know what the #s were before the tuning?

Yes. 668 rwhp and 626 rwtq

 

[STUGOTS]

Do you know what the #s were before the tuning?

Yes. 668 rwhp and 626 rwtq

hell of a tuning job

 

[Sleeper]

hell of a tuning job

MY THOUGHTS, EXACTLY

 

[repiv]

agreed, great tuning job, wish he was in vegas

 

[STUGOTS]

I'd let him tune EVERY time

 

[Sleeper]

Just realized I forgot to mention an interesting obsevation. The car now makes more rw torque at 2,500 rpm (509 ft. lbs.) than the PEAK rw torque of the C6 ZO-6, and the Ford GT.

 

[INSOMNIAC]

726 rwhp, and

687 rwtq

It seems like you hit this number on a stock block with Paxton, larger injectors, Corsa track exhaust. Stock short block, stock heads, stock cam, stock headers and standard Paxton pulley. Pretty impressive

Keep in mind though at 700 + RWHP you are pushing the limits of the stock cast pistons. I would run at least 100 Octane gas in that car as cheap insurance.

 

[repiv]

What characteristic exactly on the stock pistons creates the limit. I know it exists, but what would running 100 octane do, other than reducing chance of detonation? Is it cylinder pressure that limits the HP & TQ numbers w. stock cast pistons?

 

[INSOMNIAC]

What characteristic exactly on the stock pistons creates the limit. I know it exists, but what would running 100 octane do, other than reducing chance of detonation? Is it cylinder pressure that limits the HP & TQ numbers w. stock cast pistons?

Stock pistons are cast and they can't handle cylinder pressures over a certain limit. But that is not the only problem with them. Thay are the weakest link in the engine and you might blow a piston due to many reasons, even with much lower RWHP levels. Detonation is one of these reasons. Higher octane gas burns slowly and reduces combustion temperatures and reduces detonation. Detonation might cause you to blow a piston. There is probably 10 pages of details to this but I don't feel like typing.

100 Octane or Higher Octane gas is always a cheap insurance on any Forced Induction (Supercharged or Twin Turbo) car.

 

[SRTRICKY]

I heard 700 should be the max on a stock engine! Impressive numbers anyways

 

[Viper X]

Some of us with Paxtons have gone to water / alcohol injection to cool the combustion chambers and help keep them cleaner. Mine will be installed next week. Bought it from "Cooling Mist" and it looks very well thought out.

As to peak Paxton boost level, they are reported to be between 7 and 8 psi by Paxton. I have found that they get a little higher with rpm and can get to 9 psi.

Good numbers, good tuning at peak. It also sounds like good tuning lower in the rpm range too and that's important. I've now got about 15,000 miles on my engine at 750 rwhp. No engine problems yet with several track days and trips to the drags, knock on wood ..... Fact is you really don't run the car at peak very long or very often. The 1/2 mile and 1 mile drags would be the exception during the Silver State, but that's about it. At the track, the car has sooo much power, you really can't use it much of the time and may even be at a slight disadvantage based upon your driving skills.

Dan

 

[Sleeper]

INSOMNIAC Thank you for the complement and for your input.

Many overlook the fact that SRT pistons are hypereutectic, placing them somewhere between cast and forged products in terms of strength and heat durability. Focusing on peak horsepower is misdirected.

I agree with your concern over cylinder pressure. Also, the upper ring on the stock pistons is near the top of the piston. So both piston and rings are vulnerable to excesses in boost pressure.

I agree with your concern about premature explosion = detonation. A consevative approach to tuning is the safety factor here. Limiting timing advance at higher rpm's and controlling A/F ratio address this issue. Even highly tuned Vipers have relatively low specific output, so the stock internals do well with modest power gains.

 

[Sleeper]

I've now got about 15,000 miles on my engine at 750 rwhp.

No engine problems yet with several track days and trips to the drags, knock on wood .....

Fact is you really don't run the car at peak very long or very often. At the track, the car has sooo much power, you really can't use it much of the time and may even be at a slight disadvantage based upon your driving skills.

Thanks ViperX for these observations and your kind words. I built my car to optimize it's road course abilities, including a Moton suspension, roll bar and lightweight flywheel. I do not need any more power, and will not be using the peak levels except for short periods.

But honestly, I do love stabbing the throttle on my way to the grocery store!

TD

 

[Sleeper]

Some of us with Paxtons have gone to water / alcohol injection to cool the combustion chambers and help keep them cleaner.

My water-ethanol system is still under development, but here is a preliminary picture:

 

[Daddy Long Stroke]

INSOMNIAC Thank you for the complement and for your input.

Many overlook the fact that SRT pistons are hypereutectic, placing them somewhere between cast and forged products in terms of strength and heat durability. Focusing on peak horsepower is misdirected.

So,
1996-1999 forged pistons

2000-2002 cast pistons

2003-current Hypereutectic pistons

Correct?

 

[STUGOTS]

Some of us with Paxtons have gone to water / alcohol injection to cool the combustion chambers and help keep them cleaner.

My water-ethanol system is still under development, but here is preliminary picture:

Bud????????? LMAO that is coooooooooooooooool

 

[SRTRICKY]

Thats tooo sweet

 

[GR8_ASP]

INSOMNIAC Thank you for the complement and for your input.

Many overlook the fact that SRT pistons are hypereutectic, placing them somewhere between cast and forged products in terms of strength and heat durability. Focusing on peak horsepower is misdirected.

So,
1996-1999 forged pistons

2000-2002 cast pistons

2003-current Hypereutectic pistons

Correct?

Hypereutectic are cast and indicate a high level of silicone in the aluminum alloy.