Top times at Holley LS Fest yet why no trophy? | Project C5 Corvette Z06

Update by J.G. Pasterjak to the Chevrolet Corvette Z06 project car
Sep 15, 2021

Photography Credit: ABI Photo

Not content with just six minutes of competition time at Solo Nats, we struck out early from Nebraska to hit Holley LS Fest and the Road Course Challenge presented by Grassroots Motorsports and B&M.

Held as part of the massive Chevy-based gathering in Holley’s hometown of Bowling Green, Kentucky, the Road Course Challenge uses the West Course of NCM Motorsports Park, which features the exciting Turn 1a/1b complex, and the high-speed Turn 5 which faster cars enter at more than 110 mph.

[NCM Motorsports Park’s Corvette Experience]

Our only modifications from autocross configuration were switching out our flat-plane spoiler for the track wing and installing a set of broken-in set of Hoosier A7 tires. No alignment changes, no changes to setting on the Ridetech shocks, our C5 Corvette performs great in autocross or track settings with identical suspension settings.

Photography Credit: J.G. Pasterjak

Apparently, our Holley Dominator-controlled LS3 in the Corvette liked the environment of Holley LS Fest, and we were the fastest car on track from the very first session. Despite being at a serious power deficit to some of our competition–at LS Fest, 560 flywheel horsepower isn’t really “a lot”–the exceptionally drivable and well-balanced chassis more than made up for the thrust deficit.

Also coming in very handy was the Garmin Catalyst Performance Analyzer, which made it extremely simple to digest and absorb data after each session, even though we were at the track alone and on a tight schedule.

Photography Credit: J.G. Pasterjak

[The Garmin Catalyst made a huge splash when it was introduced to the track enthusiast market. A year later, is it still a revolution?]

Most satisfying, on Day 2 of competition, we were able to match the Catalyst’s optimal target lap time to the hundredth of a second, all thanks to the kind but slightly terse tutelage of the friendly robot lady who lives inside the Catalyst and provides tips and encouragement throughout each session. She was supportive or critical at all the right times, and never gave us advice that slowed us down–when we were able to properly execute on it.

Photography Credit: ABI Photo

The other accessory making the weekend more satisfying was some new duds. We’re huge believers in the human factors equation of going fast in a race car, and if you’re not comfortable, you’re going to have a harder time being competitive.

That means a good-fitting driving suit is more than a safety necessity, but a legitimate tool of performance. Complicating this is anatomy. Not all drivers are shaped the same, and for our more fire-plug-shaped friends out there, we feel your pain when it comes to finding an off-the-rack suit that doesn’t pinch, bind or pull somewhere (and never someplace fun).

That’s until we tried on a Simpson Six O, which is the best suit we’ve ever experienced for those stockier of build. Most impressive is the shoulder room. It’s easy to find a suit to fit over big hips or a beer gut, but they all seem to restrict shoulder movement. The Six O feels like comfortable pajamas up top, with plenty of range of motion and great cross-body reach, even when strapped in.

Photography Credit: J.G. Pasterjak

Throughout the entire event–as has been the case with our C5 since we completed the engine swap–it ran flawlessly and was easy and friendly to drive. At this point, the 560-horsepower LS3 engine from Blueprint Engines is well broken in, and well protected by the Aviaid dry-sump system.

The twin-disc clutch from Mantic Clutch USA spins up quickly thanks to its titanium drive blocks, making rev matching a snap on downshifts as the unit engages the same time, every time. It’s a hugely transparent but powerful part of the performance equation.

[Why a multi-disc clutch saves weight while Increasing clamp load.]

And the GearFX-prepped transmission and rear end, now fitted with the WaveTrac differential, complete the entire driveline and turn the Corvette into a real joy to drive. (Also, we should note that it was certainly satisfying to row our B&M shifter at an event that we co-sponsor with them.)

Ultimately we turned the fastest laps in almost every session we ran, and the fastest seven laps overall of the weekend. Since we were an event sponsor, we DQed ourselves from the event’s official results, but as a proof-of-performance exercise, our Holley Dominator-powered Corvette was flawless where it mattered most, which was at Holley’s party.

Notes going forward? Yeah, both the data and our seat-of-the-pants g-meter are telling us we need more front downforce, especially in high-speed corners. Our aero imbalance in faster stuff results in a controllable but speed-limiting push in fast corners, like NCM’s Turn 5. We’ll try and address this issue with some parts from Nine Lives Racing and more intense front downforce.

[Shop Visit: Nine Lives Racing]

Also, cooling is very much still an issue. With the E85 tune and Improved Racing oil cooler, we can run longer before temps begin to spike, but oil temps will eventually top 260 and coolant will eventually top 230. At those levels you’re not in danger of instantly destroying an engine, but you certainly aren’t producing optimum power. It’s probably time to fabricate a more aggressive radiator mount that draws more air in the front and more efficiently expels it out the hood. Time to oil up the sheet metal brake.

Photography Credit: ABI Photo

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View comments on the GRM forums
84FSP UltraDork
9/14/21 1:03 p.m.

That is really impressive given how new the car is to the team.  Great work there JG.

CrustyRedXpress GRM+ Memberand HalfDork
9/14/21 1:56 p.m.

"Most satisfying, on Day 2 of competition, we were able to match the Catalyst’s optimal target lap time to the hundredth of a second." 

Nice job-especially for being out there alone. 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
9/14/21 2:33 p.m.

Self-DQ is a classy move.

BA5 GRM+ Memberand Reader
9/14/21 2:37 p.m.

The car sounds like a C5.R in the video.

alfadriver GRM+ Memberand MegaDork
9/14/21 2:43 p.m.

Can you integrate better cooling with more front down force?

And do you think the problems is not enough air getting in, or air not being able to get back out again?

JG Pasterjak
JG Pasterjak Production/Art Director
9/14/21 4:25 p.m.
alfadriver said:

Can you integrate better cooling with more front down force?

And do you think the problems is not enough air getting in, or air not being able to get back out again?

Hopefully and probably yes to all.

alfadriver GRM+ Memberand MegaDork
9/14/21 4:29 p.m.

In reply to JG Pasterjak :

I assume you are consulting the aero advisors....  

Seems like a good idea to have them show some of the modeling tools available to the public- if they use them.  While it may only apply to the brave coders out there who race, having them add to the group of people doing aero modeling would be a very good thing.  (there are a number of open source CFD tools that are way, way, way over my head)

Tom Suddard
Tom Suddard GRM+ Memberand Director of Marketing & Digital Assets
9/14/21 5:21 p.m.

In reply to alfadriver :

Not sure how far JG will go, but I've got a big story on this in the works with the 350Z. Like, "computers currently computing" in the works :) 

alfadriver GRM+ Memberand MegaDork
9/14/21 6:01 p.m.

In reply to Tom Suddard :

Very cool!  And Very much looking forward to it!

JG Pasterjak
JG Pasterjak Production/Art Director
9/14/21 6:17 p.m.

In reply to alfadriver :

Yeah Tom has already waded into that pool, and I'm hoping to just get caught in some of the splash. 

alfadriver GRM+ Memberand MegaDork
9/14/21 6:54 p.m.

In reply to JG Pasterjak :

Can you borrow Tom's 3D scanner for the vette?

deaconblue New Reader
9/30/21 12:39 p.m.

First a belated congratulations on the results!

Not sure of all the details of what they did with the C5-R race cars, but a bit of research may give you some ideas as well.

Another option could be a complete change from the bottom feeder to front feeder design with something like the Duraflex; TS, ZR, Stingray Z or the CF Performance C5.5 front bumper covers. 

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