: 9 inch D3 pulley: Results



s4ologist
11-12-09, 02:20 PM
Well, I went ahead and did it. I took my car back to Hennessey to have the work done. They work with a ton of these cars, and they treated me right last time. So we went to Houston for a little R&R, dropping the V2 off on the way. I went with the crank pulley because it is a faster install, is reversible, and doesn't require taking the SC apart. I expected an about 30 HP and maybe 50 TQ improvement. The following numbers all come from Hennessey's dyno.

Before: 521 RWHP, 485 RWTQ (temp in the low 90s)
AR Headers, Hennessey intake, tune.

After: 571 RWHP, 555 RWTQ (temp in the low 80s)
Only addition: D3 crank pulley.

My stock numbers were: 457 RWHP, 464 RWTQ.

So I got 50HP and 70TQ (almost 15% increase) from the mildest pulley, which took me from maybe 7.5 psi (lowish after the headers) to about 10 psi (barely over the stock 9psi). No complaints here. The change is quite noticeable, especially, well, everywhere. 4th gear almost feels like 3rd did before. 6th is impressive on the highway. I feel like a goofball saying that the car is more "driveable" with the extra TQ, but that's how it feels. That is a comment usually reseverd for cars that needed more torque, not one that could roast the tires at will stock. The extra TQ (reaching its peak at about 3600 rpm, and above 500 from 2500 to 5500) really enhances that "any gear, any time" feeling. Traction is another issue, but already was from the factory.

I think I'm done with performance mods. My wife doesn't believe me, but after reaching the level I wanted with my S4, I didn't touch it for 4 years.

Vrocks
11-12-09, 02:39 PM
Great numbers.

It's nice to have a clear cut picture to see what each mod, or group of mods, did to boost performance.

I'm thinking about adding a CAI and AR headers this spring or summer. Would you say the car is substantially loud after adding them? Is it like the usual modded Vette or Mustang exhaust sound (you can hear it in your car when they're a 1/4 mile away)?

Thanks

LITTLEELVISDAN
11-12-09, 02:40 PM
So all your mods combined gained you 114 RWHP and 91 RWTQ? Very nice... That gain on any car is going to be very noticeable......

Gary Wells
11-12-09, 03:52 PM
What's the build date on your car, pls?
Stick, right?

neuronbob
11-12-09, 04:22 PM
Wow, those are impressive numbers. Thank you for sharing.

Razorecko
11-12-09, 05:04 PM
VERY impressive to get those #'s w/out going into 12/13psi

Doct
11-12-09, 05:52 PM
Great numbers man! I am impressed that with headers, intake, tune, you gained roughly 64hp with the boost drop off from the headers. There seems to be a lot left on the table from factory tune which is great!

zr1vet
11-12-09, 08:14 PM
Very nice numbers. Thanks for sharing. Do you have stock mufflers? How's the sound?

c4ss
11-12-09, 08:50 PM
Stick, right?

:yeah:

Gary Wells
11-12-09, 10:11 PM
Great #'s, & I must have missed the tranny in the previous postings. You are very fortunate to have Hennessey near by.

SlvrBullIT
11-12-09, 11:51 PM
Speaking of Hennessy, drove by them today omw to SecureHouston and saw Dave's V from I-10..... So wanted to go check his ride out....

wfo
11-13-09, 08:40 AM
Question:

What does Hennessey's shop look inside..

1.Clean and organized/well managed chaos?

2.Crazy/hectic and scattered chaos?

s4ologist
11-13-09, 02:25 PM
The car is a manual. I have stock mufflers, and am pleased with the sound. My brother, who has had multiple modded mustangs and vettes, said he thought it sounded stock when I gave him a ride (he had never seen the car before the AR headers). It isn't much louder than stock at idle or cruise. On the HWY, I can listen to music quietly if I want without being bothered by the exhaust. It wakes up with proper throttle application, though!

Hennessey's shop seems clean and well-organized. You go back there, and there are probably 15 or so cars on lifts (lots of vipers, vettes, and camaros). They have been very professional with me the two times I was there.

I'll have to check on the build date (got the car 12/08).

Razorecko
11-14-09, 11:10 AM
The car is a manual. I have stock mufflers, and am pleased with the sound. My brother, who has had multiple modded mustangs and vettes, said he thought it sounded stock when I gave him a ride (he had never seen the car before the AR headers). It isn't much louder than stock at idle or cruise. On the HWY, I can listen to music quietly if I want without being bothered by the exhaust. It wakes up with proper throttle application, though!

Hennessey's shop seems clean and well-organized. You go back there, and there are probably 15 or so cars on lifts (lots of vipers, vettes, and camaros). They have been very professional with me the two times I was there.

I'll have to check on the build date (got the car 12/08).

Gotta love having a manual - I'm guessing you break traction easy in 3rd now. Also do you have any cel lights from the headers ? Or was that taken out with the tune ? Is it just straight or headers w/ high flow cats on the oem exhaust

s4ologist
11-14-09, 08:53 PM
Yes, traction is lost in 3rd gear more often now. 2nd is a joke without proper modulation (or a fantastic surface).

The AR header system is headers, one cat deleted on each side, and the remaining cat on each side is of the "high-flow" variety. The rear O2 sensor was turned of to prevent the CEL from coming on. The axle-back portion of the exhaust (mufflers) is stock.

Unfortunately, as of yesterday, the CEL did come on (see other post). I think it's the radiator fan.