04-03-2021, 02:32 PM | #1 |
Drives: 2018 Chevrolet Camaro 2SS 1LE 6M Join Date: Jul 2019
Location: California
Posts: 283
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ATI Underdrive pulley.
Modding my Camaro has been a journey. It started when I bought the car and almost immediately had it baselined to see what my starting point would be. 404 HP seems like a very respectable place to start. The very first thing I did was add a flex fuel kit and get the car tuned. It picked up 34 HP as easy as you please.
Later, I added a Pray Performance ported intake manifold, a Soler Performance ported throttle body, a RotoFab dry intake and some New Era cat delete pipes. Had it retuned. The car put down 464 HP. So far, so good. Every mod had behaved predictably and gained an appropriate amount of power. Next I added a Pray ported MSD intake manifold. It made about the same torque and picked up about 15 peak WHP, and over 30 WHP above 6,000 RPM. Nothing unexpected. 479 WHP is quite respectable, 75 WHP over what the car had put down stock. Here is where it gets confusing, at least for me. In January of this year I installed ARH 1 7/8" headers and full exhaust with X-pipe into the stock NPP muffler. The car made less power-significantly less. After spending a great deal of time tuning and tweaking, the car got back up to 472 WHP- 7 WHP less than it made with the stock exhaust manifolds. WTF? I still don't know why. So, in an attempt to get the car as close to 500 RWHP before I do a cam and heads, I installed the ATI 10% under drive pulley. The car picked up 3 ft-lbs of torque and about 8 WHP on the dyno. I also feel less harmonic vibration from the engine. The ATI pulley has to be one of my favorite modifications, second only to switching to E85.I highly recommend it. In a nutshell, the car is making 481 WHP, a 77 WHP gain from stock. The last few HP have been very hard to come by. Had I known what I know now three months ago, I would have skipped doing the headers. All numbers are SAE. I hope that my experiences will be helpful and informative for others.
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Bolt-ons.
Last edited by NA18CamaroSS; 04-03-2021 at 02:38 PM. Reason: # |
04-03-2021, 03:21 PM | #2 |
Drives: like an old lady Join Date: Jun 2012
Location: indiana
Posts: 2,396
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awesome post. my power curve above 6k is a lot flatter than yours. very similar mods. mine peaks around 5900 and holds very flat to 6700.
i have 2" headers & full 3" exhaust mamo ported msd stock LT5 tb rotofab cai ethanol i have a damper but its still holding down a table in my dining room. cant put a relative dyno number on my car as it was tuned on a dynodynamics dyno and it reads very low. dynojet "conversion" showed ~494. dyno numbers are whatever, the car picked up 8+ mph over stock with 0 weight reduction.
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2016+ camaro: everyone’s first car
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04-03-2021, 05:20 PM | #3 |
LIL SLOW SS
Drives: 2017 SS Join Date: Jul 2020
Location: CA
Posts: 108
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Nice write up, you’re always very informative!
So you think if you would’ve stayed with the Test pipes you’d be at 488whp? I’ve heard Granatelli wires actually pick up about 5whp. That would be interesting to see on the dyno should put you at 485whp Atleast |
04-03-2021, 08:05 PM | #4 |
Drives: 2017 1SS cruiser/ 1985 Z28 racecar Join Date: Nov 2018
Location: Annapolis MD
Posts: 77
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I’m somewhat in the same situation as you also. So my first tune was roto fab, ported TB and ported stock IM on pump gas and it made 426, dumped in E85 and it made 449.
A couple months later I installed the 2 inch ARH headers with high flow cats, 3 inch X pipe into the stock NPP and it made 486. A hug jump and I was very pleased. A couple more months later I was shooting for the 500 mark so I added the LT2, ported Katech 95 Tb and the ATI damper. It made more power but I have to say I was a bit disappointed with the final results.....493. It made more power which I’m happy about but all the hype about the LT2 I honestly was expecting more. Oh well it is what it is and the parts are on and the money is spent.
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17 SS 2” ARH headers, high flow cats, and 3”X pipe into NPP, Katech ported 95 mm TB, LT2 IM, roto fab, DSX FF, Katech 160* BMR motor mounts, ATI damper, 493 RWHP
https://youtu.be/E-MDIyLtV48 |
04-03-2021, 08:27 PM | #5 |
Drives: 2018 Chevrolet Camaro 2SS 1LE 6M Join Date: Jul 2019
Location: California
Posts: 283
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I wish that were true. When the numbers came in after the header, install I threw on the Granatelli wires and ignition coils. I still have the stock manifolds and exhaust, but I sold the test pipes. I'm really tempted to buy another set of test pipes and throw the stock manifolds back on the car to see what happens.
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Bolt-ons.
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04-03-2021, 11:39 PM | #6 | |
Drives: 17 2SS, 8L90, Cam, Heads, E85 Join Date: Dec 2016
Location: US
Posts: 1,201
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Quote:
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04-04-2021, 12:41 AM | #7 |
Drives: 2017 SS Join Date: Jul 2017
Location: SoCal
Posts: 45
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Crazy but we made exactly thesame number fbo e85. I recently added ATI UD Pulley so it safe to say I’m around thesame power as you.
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06-01-2021, 07:03 AM | #8 |
Drives: 2022 Lt1 A10 Join Date: Nov 2015
Location: clark, mo
Posts: 8,860
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Those are good numbers. Congrats
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2022 Lt1 6.2 A10, Maggie 2300, THPSI Port Inj/10 rib, Rotofab, E, Nickey, SCOL, Griptech, RC Bandits, Hoosiers/MT 9.80@142.96 1.44 60ft, 6.34@112 707/669 RWHP/TRQ. 16SS Maggie 2650 9.41@147 1.35 60ft, 5.99@119. 16 C7 A8 10.90@128 Bolt on stuff
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06-01-2021, 07:11 AM | #9 |
Drives: 2022 Lt1 A10 Join Date: Nov 2015
Location: clark, mo
Posts: 8,860
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I was surprised to see you lost hp on the long tubes. Mine made about 15 rwhp but it picked up 4 tenths of a second and 4 mph in the 1/4. I just added the Ported MSD and we picked up about 18 rwhp so now we are at 462. We are going back to the track tomorrow night to see what we pick up there. I hope we'll see some 10.90s or maybe a high 80.
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2022 Lt1 6.2 A10, Maggie 2300, THPSI Port Inj/10 rib, Rotofab, E, Nickey, SCOL, Griptech, RC Bandits, Hoosiers/MT 9.80@142.96 1.44 60ft, 6.34@112 707/669 RWHP/TRQ. 16SS Maggie 2650 9.41@147 1.35 60ft, 5.99@119. 16 C7 A8 10.90@128 Bolt on stuff
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06-02-2021, 08:22 PM | #10 | |
Drives: 2021 LT1 10 speed auto Join Date: May 2013
Location: Connecticut
Posts: 2,343
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Quote:
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06-02-2021, 09:00 PM | #11 |
Drives: Chevy Camaro SS Join Date: Nov 2019
Location: Indiana
Posts: 225
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I’m stilling running the factory a/c belt with my ATI
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2017 1SS:Hi-Ram, FBO, OTR ram air, Circle D converter. Previous PB: 11.07 @124 1/4 7.1 @100 1/8 1.6 60’ w/2” longtubes, 95mm hi-ram, OTR ramair, flex fuel |
06-03-2021, 06:51 AM | #12 |
Drives: 2021 LT1 10 speed auto Join Date: May 2013
Location: Connecticut
Posts: 2,343
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OK, great to hear. Was replacing the balancer a easy job for you? What problems did you encounter? and you did use the 10 % underdrive unit correct? Just wondering if the ATI unit creates a 10% underdrive , how do the belts still fit?
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06-03-2021, 07:35 AM | #13 | |
Drives: 2019 Camaro 1LE Shock Candy Join Date: Mar 2016
Location: Garage
Posts: 1,757
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Quote:
“Harmonic dampers are typically press-fit and next-to-impossible to properly remove and install without the right tools.” Here’s a good read to understand what you will encounter if you try it yourself. https://www.onallcylinders.com/2020/...e-right-tools/
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LT4 1.7 Supercharger snout ported & Meth
103 Katech TB, KATECH Custom Heads, DSX In-line fuel TSP Headers, Spec P Super Twin Clutch, TSP EL C7 CAM Diamond Piston & Manley Rods, Roto Fab Big Gulp BTR Push Rods,LS7 Lifters, ARP, FI Chiller, Kirkey Seats SJM Line Lock, Hurst Pistol Grip. 747/739 RWHP street tune - 821/794 RWHP track tune 101 octane. 2014 Mini Cooper countryman S All4 M6 daily driver |
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06-03-2021, 09:45 AM | #14 |
Drives: Chevy Camaro SS Join Date: Nov 2019
Location: Indiana
Posts: 225
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It wasn’t too bad. But I’ve also got an uncle that runs a machine shop and warned me before to check and make sure it didn’t need honed before install like the instructions mentioned, and I’ve also got the ATI dampener puller/install kit which makes thing a pretty smooth. Ya, it’s a 10% unit.
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2017 1SS:Hi-Ram, FBO, OTR ram air, Circle D converter. Previous PB: 11.07 @124 1/4 7.1 @100 1/8 1.6 60’ w/2” longtubes, 95mm hi-ram, OTR ramair, flex fuel |
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