New Dyno #s. Stock 2.4 vs. RPi goodies + Dyno Tune

RPIpower · 08-14-2007, 06:16 PM

Just got done with tuning a 2.4L this afternoon and thought you guys might like to see the results.

The orange graph was done on the same car when it was stock. The blue line was the car with the RPi stealth (dual) exhaust, RPi ram air intake, RPi stage 2 clutch + Fidanza flywheel. The red line was done with the existing mods but w/ tuning. When the 2.4 goes into PE or power enrichment mode, the car starts to run incredibly rich. The ecu also has a slight delay (miliseconds) when adjusting fuel in PE mode. We were able to clean AFRs up and tune the ignition advance/retard. Results? One happy sky owner.

cerberus · 08-14-2007, 10:57 PM

OH HELL YES I LIKE!!!

The car feels eff-in great post tune. Transistions are really good. This is the car I wanted back in '05. Oh yeah, sshh, dont tell dealer. Yeah, right. I already let them take it out for a spin and both guys came back with big ol' chit eatin grins. Hmm. Fan was blowin pretty good and temps were up when Tim got back, but hey, his eyes were about as wide as his grin.

RPIpower · 08-15-2007, 01:08 AM

Quote:

Originally Posted by cerberus

OH HELL YES I LIKE!!!

The car feels eff-in great post tune. Transistions are really good. This is the car I wanted back in '05. Oh yeah, sshh, dont tell dealer. Yeah, right. I already let them take it out for a spin and both guys came back with big ol' chit eatin grins. Hmm. Fan was blowin pretty good and temps were up when Tim got back, but hey, his eyes were about as wide as his grin.

Well, I'm glad you like it. It's safe to say, you are easily over 200hp at the crank.

cerberus · 08-15-2007, 01:38 AM

Quote:

Originally Posted by RPIpower

Well, I'm glad you like it. It's safe to say, you are easily over 200hp at the crank.

Eeey-yup. The numbers work, and the flywheel opens up access to the increased WHP. Why couldn't the do this from the factory? !

SSC_Summit · 08-15-2007, 02:35 AM

Yup - this one is a winner. Stock 2.4 feels torquey but then ... nothing. This one pulls and keeps on pulling. Shifts are much quicker and cleaner as well. Obviously sounds nicer than stock.

Very nice guys. Well done.

stonebreaker · 08-15-2007, 09:43 AM

Quote:

Originally Posted by cerberus

Eeey-yup. The numbers work, and the flywheel opens up access to the increased WHP. Why couldn't the do this from the factory? !

The factory has different aims than you do. The heavy flywheels smooth out the idle and make it easier for the average person to engage the clutch without stalling. The EPA is extremely tough on noise levels which is why they have to offer a cat-back instead of adding it straight from the factory (although the LS7's WOT exhaust valve is really cool), and the factory tune is designed to make sure a car that hasn't had a tuneup in 100,000 miles still runs good. It would sure make GM's life easier if all they had to deal with were gearheads.

I'm always amazed what GM's engineers can do with factory parts when they don't have to limit themselves to production values. I saw a big block fuel-injected impala, for example, that used TWO mafs. I have no idea how they integrated the two values to come up with one value to feed the computer.

cerberus · 08-15-2007, 10:25 AM

True, sb. Not a serious question.

The stock 2.4 is a very pleasant ride setup for a broad audience. My own preferences and expectations in my cars can be pretty specific.

Ag94Whoop · 08-15-2007, 10:53 AM

I have debated the flywheel but not sure if I want it....
have heard you lose some torque with it and I LOVE the feel of torque

I have to say my mods work, whether people believe it or not...

RPIpower · 08-15-2007, 12:25 PM

Quote:

Originally Posted by Ag94Whoop

I have debated the flywheel but not sure if I want it....
have heard you lose some torque with it and I LOVE the feel of torque

I have to say my mods work, whether people believe it or not...

Everyone who downplayed the flywheel don't or never had one on their 2.4L Sky. In theory, yes, you do lose some tq due to the lighter intertia weight of the flywheel, but it works out well on this car. You know how I am Bill. Try/test it yourself. We hear 30whp from exhausts, I've seen 3whp. We've heard 15-20whp on an intake, I saw an 18whp loss.

stonebreaker · 08-15-2007, 12:59 PM

Quote:

Originally Posted by Ag94Whoop

I have debated the flywheel but not sure if I want it....
have heard you lose some torque with it and I LOVE the feel of torque

I have to say my mods work, whether people believe it or not...

Where you lose the 'feeling' of torque is on the initial launch and at the gearchanges, but will pull harder through the rev range. The car *should* be a little faster overall because some of the energy you were using to spin up the flywheel is now going to the rear tires. Theoretically, anyway. <disclaimer> I'm a drag racer and have always raced automatics. I'm just repeating what I've heard from some of my buddies who drive manuals at the track. </disclaimer>

stonebreaker · 08-15-2007, 01:02 PM

Quote:

Originally Posted by cerberus

True, sb. Not a serious question.

The stock 2.4 is a very pleasant ride setup for a broad audience. My own preferences and expectations in my cars can be pretty specific.

It kind of dawned on me you were probably being rhetorical about 5 minutes after I posted that. (_8^(|) D'oh!

08-14-2007, 06:16 PM	#1 (permalink)
RPIpower Supporting Vendor Join Date: Nov 2006 Posts: 1,722 My Photos: (0)	New Dyno #s. Stock 2.4 vs. RPi goodies + Dyno Tune Just got done with tuning a 2.4L this afternoon and thought you guys might like to see the results. The orange graph was done on the same car when it was stock. The blue line was the car with the RPi stealth (dual) exhaust, RPi ram air intake, RPi stage 2 clutch + Fidanza flywheel. The red line was done with the existing mods but w/ tuning. When the 2.4 goes into PE or power enrichment mode, the car starts to run incredibly rich. The ecu also has a slight delay (miliseconds) when adjusting fuel in PE mode. We were able to clean AFRs up and tune the ignition advance/retard. Results? One happy sky owner. __________________ Eloy "Brutus" #001 RPi 2.4GTS Race Precision, Inc. 7029 Marcelle Street Paramount, CA 90723 562-630-5966 www.raceprecision.com Last edited by RPIpower : 08-14-2007 at 06:20 PM.

08-15-2007, 10:53 AM	#8 (permalink)
Ag94Whoop Senior Member Join Date: Feb 2007 Location: Corinth, TX Posts: 434 My Photos: (9)	I have debated the flywheel but not sure if I want it.... have heard you lose some torque with it and I LOVE the feel of torque I have to say my mods work, whether people believe it or not... __________________ HEAVENLY #1668 Silver Pearl 2.4, red/black lthr, Fosgate/JL sound. Lil Chromies. Custom mats. Chrome and black custom wheels, Eibach springs, Custom Calvary 3 crosses WR, Candy Red Rally 10" stripes and side scoop stripes, Magnaflow, Custom RAI

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08-14-2007, 10:57 PM	#2 (permalink)
cerberus Super Moderator Join Date: Mar 2006 Posts: 2,163 My Photos: (19)	OH HELL YES I LIKE!!! The car feels eff-in great post tune. Transistions are really good. This is the car I wanted back in '05. Oh yeah, sshh, dont tell dealer. Yeah, right. I already let them take it out for a spin and both guys came back with big ol' chit eatin grins. Hmm. Fan was blowin pretty good and temps were up when Tim got back, but hey, his eyes were about as wide as his grin.

08-15-2007, 10:25 AM	#7 (permalink)
cerberus Super Moderator Join Date: Mar 2006 Posts: 2,163 My Photos: (19)	True, sb. Not a serious question. The stock 2.4 is a very pleasant ride setup for a broad audience. My own preferences and expectations in my cars can be pretty specific.

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