Serpentine Syst Needed for the Track

[TonyV]

Guys I've been track testing the car before I paint it but i'm giving up on the current serpentine syst. It works great on the street no issues but on the track with a redline at 7200 it seems to have a dynamic issue where it just shreds the belt. Currently its what I call a "spread" system where the A/C compressor and Alt sit outside the heads giving me room in front between radiator and block. There's a bit of run between idler and pulley's that I think start flexing or bouncing that just destroys the belt. On the street ~500 miles no issues but on the track I can't make it one day on sessions without a disaster, the latest one taking my dry sump belt with it and bending the shaft....Anyone out there running a serpentine syst that's more compact without the large unsupported runs between pulleys or idlers? I'm looking for track experience with 7000 rpm redlines.

[TonyV]

Should've gave a little info on the engine....LSX block and 750 dyno HP at the crank Bordix LS7 heads...

[raustinss]

Ron Sutton and a few other fellas are recommending and using Drive Junky systems , they incorporate a higher amount of belt "wrap" for the power steering pump than most other systems . check them out they might just have what you need . Good Luck

[65 drop top]

Look into Drive Junky or Wegner

[badazz81z28]

What exactly is happening to the belt? The Z06 stock system seems to work fine. Granted the aftermarket systems are more compact, they are very expensive.

[TonyV]

Couldn't tell exactly what's going on but the runs from pulley to pulley seem to be too much for race applications. I loved the set up and how it worked for the street but its the second time I've lost a belt at the track causing some collateral damage. We we're checking the belt after every session to see if there was any tears or cracks. also it was a brand new belt before heading out.

Here's what I was running....notice I didn't have the A/C on yet so the pic is exactly my setup. When I select a new system i'd like pick one so I can use my alternator/ ATI balancer and possible my power steering pump. Hate to have to spend a bunch more money switching systems.

https://static1.pt-content.com/images/pt/2018/02/uf7F2B1-1.jpg

[71RS/SS396]

I've been using a Wegner Motorsports drive for 3 years with plenty of track use that sees 8,000 rpm without issue.

[rickpaw]

I don't have direct experience with belt shredding yet, but I've read that the stock tensioner (upper left) tend to flex under sustained high rpm, thus leading to belt failures. The Katech belt tensioner seems to address this issue.

http://store.katechengines.com/billet-belt-tensioner-p2.aspx

Something to try out first, since it's $130 vs switching to all new system. I will run this in mine when I get the car going again as a preventative measure.

[TonyV]

Nice options...The Wegner i'll have to find out what I can use with my existing equipment.

The Katech option is really a nice option and maybe something I would've like to have tried before that last track session because the stock tensioner seemed out matched for what I was asking it to do.....but I think i'm going to go with what I call the "compact version" similar to the Wegner style.

[CarlC]

Has it been confirmed that max engine RPM is causing the issue, or could it be high acceleration / deceleration events that could be causing the belt damage?

[TonyV]

Has it been confirmed that max engine RPM is causing the issue, or could it be high acceleration / deceleration events that could be causing the belt damage?

Carl you bring up a great question.....we were sitting around here at work thinking about the dynamics (avoiding our day job) and its possible that the deceleration against the alternator could cause a "wave" or disruption from the internal inertia. Maybe try a new tensioner along with a larger pulley on the alternator....I've got room in regards to AMPs at RPM. But hey we're just a bunch of aerospace engineers and we don't use belts too often....but I think your idea has merit.

[dontlifttoshift]

Isn't that why the corvettes had clutches on the alternator?

I am curious about your setup, though....mostly because of my weird infatuation of mechanical things failing. When the belt fails, what happens?

Can we see pictures of you accessory drive?

[TonyV]

I can get I pic but honestly the one I posted is exactly what i'm using other than I used a billet PS pulley....so that picture will be better than me trying to squeeze off one in the car. The first time it failed I started hearing like sand hitting the car, actually I thought the transmission was going to crap. but what it was, the first two ribs of the belt start peeling off and hitting everything in its path. it severed my oil lines and radiator lines. where I was on the throttle no clue other than I was getting into it. Second time I just finished a quick chicane and was pouring it on in 3rd >6000 then I started to hear that "sand hitting the car noise" initially I didn't recognize it but when I got into the pits it all came back but it was never nearly as much noise as the first time.....although this time there was nothing left of the belt...I just found pcs everywhere.

[Ron Sutton]

The unit we find to be the very best for High RPM LS engines on track and/or autocross usage is Here:
http://www.ronsuttonracetechnology.com/catalog/?page=326 (http://www.ronsuttonracetechnology.com/catalog/?page=326)

The reasons why are on that page.

:cheers:

[TonyV]

The unit we find to be the very best for High RPM LS engines on track and/or autocross usage is Here:
http://www.ronsuttonracetechnology.com/catalog/?page=326 (http://www.ronsuttonracetechnology.com/catalog/?page=326)

The reasons why are on that page.

:cheers:

Thanks Ron....good info and i'll have to give you a call to ask some specific questions. one off the top of my mind can I use my existing ATI Damper 917289? really appreciate the help from everyone that chimed in...

[badazz81z28]

I’m super curious to see the damage. I don’t drive my car as much as others, but if you can only get through 1 track day before an issue something else has to be off. I run the vette system and spun the LS to 6800-7000. It lived there last year at LS Fest and no issues. I’m running the same setup on my LS7.

[TonyV]

I’m super curious to see the damage. I don’t drive my car as much as others, but if you can only get through 1 track day before an issue something else has to be off. I run the vette system and spun the LS to 6800-7000. It lived there last year at LS Fest and no issues. I’m running the same setup on my LS7.

what size alternator pulley you using and are you using the stock tensioner?
BTW....we've used a laser and straight edges on all the pulley's to assure we're all aligned and in the same plane. Like I said I liked the set, they're local company and I was sold on the product when talking to the guys but I can't seem to keep this belt on during track days.
Here's a pic from my first failure where one rib just started to peel off....and cut everything in its path. I didn't take any pics on the last disaster but there was just shreds in the engine bay....couldn't find any big pcs.
https://static1.pt-content.com/images/pt/2018/02/ylJ07pC-1.jpg

[dhutton]

I have never been a fan of these accessory drives made from flat plate stock. They are inherently weaker than systems using castings with cast in reinforcement ribs and thicker cross sections. They will flex more and could easily lead to the belt riding up the pulley edge causing the belt edge damage you have experienced.

I also would not be surprised if there was an inherent resonance in that alternator hanging way out there that is energized at the high rpm where the failure occurs. Pure speculation without some kind of analysis..

Don

[CSG]

Isn't that why the corvettes had clutches on the alternator?

I am curious about your setup, though....mostly because of my weird infatuation of mechanical things failing. When the belt fails, what happens?

Can we see pictures of you accessory drive?
I know coyote engines also have a one way bearing in the alternator on manual trans cars, not on autos.

[Ron Sutton]

Thanks Ron....good info and i'll have to give you a call to ask some specific questions. one off the top of my mind can I use my existing ATI Damper 917289? really appreciate the help from everyone that chimed in...

Yes, your existing ATI Damper 917289 will work fine. That is the damper we use on our dry sumps. So you will just buy the Drive Junky LS drive system FOR the ATI Damper 917289, but WITHOUT the ATI Damper 917289. I think it drops the cost $300-400.

[Ron Sutton]

I’m super curious to see the damage. I don’t drive my car as much as others, but if you can only get through 1 track day before an issue something else has to be off. I run the vette system and spun the LS to 6800-7000. It lived there last year at LS Fest and no issues. I’m running the same setup on my LS7.

I think that is an over generalization. It depends on the track & the car.

If the car can only pull 1.3G on a road course, you would probably be fine on most road courses, & experience no bearing, crank or rod damage. So if our car doesn't pull high G's, this is less of a concern.

On the other hand, if the car is pulling 1.7G+, we need a better oil system. A base LS7 oil system, or a good road race pan & accusump, would be good on many road courses where the 1.7G lasts a short time. Realize with 1.7G ... the oil in the pan is working its way past the baffles & up the side of the sump wall ... away from the oil pickup. The Accusump is acting as a "reserve" tank providing up to 3 quarts of pressurized oil to the oiling system. But this is only good a specific number of seconds. After a time, the accusump runs out of oil ... and if the 1.7G is still happening ... we'll scar the bearings/crank/rods.

Now if we run this 1.7G+ car at Watkins Glen, Portland ... any "Roval" built on a super speedway ... or other road race tracks with loooooong sweeping, fast corners ... and the 1.7G+ is sustained for a longer duration ... a good road race oil pan & accusump WILL run out. So for these applications, we need a dry sump, because a dry sump never runs out. It continuously recirculates the oil from the tank to the engine & back to the tank.

To clarify, I'm not suggesting everyone needs a road race pan & accusump ... or dry sump. It depends on your car, the g-loads & how long the g-loads are sustained.

:cheers:

[TonyV]

I think that is an over generalization. It depends on the track & the car.

If the car can only pull 1.3G on a road course, you would probably be fine on most road courses, & experience no bearing, crank or rod damage. So if our car doesn't pull high G's, this is less of a concern.

On the other hand, if the car is pulling 1.7G+, we need a better oil system. A base LS7 oil system, or a good road race pan & accusump, would be good on many road courses where the 1.7G lasts a short time. Realize with 1.7G ... the oil in the pan is working its way past the baffles & up the side of the sump wall ... away from the oil pickup. The Accusump is acting as a "reserve" tank providing up to 3 quarts of pressurized oil to the oiling system. But this is only good a specific number of seconds. After a time, the accusump runs out of oil ... and if the 1.7G is still happening ... we'll scar the bearings/crank/rods.

Now if we run this 1.7G+ car at Watkins Glen, Portland ... any "Roval" built on a super speedway ... or other road race tracks with loooooong sweeping, fast corners ... and the 1.7G+ is sustained for a longer duration ... a good road race oil pan & accusump WILL run out. So for these applications, we need a dry sump, because a dry sump never runs out. It continuously recirculates the oil from the tank to the engine & back to the tank.

To clarify, I'm not suggesting everyone needs a road race pan & accusump ... or dry sump. It depends on your car, the g-loads & how long the g-loads are sustained.

:cheers:

although I agree with the oiling Ron statement but I think badazz81z28 was making a point with the accessory drive system(btw i'm using the dailey dry sump). Its the corvette system from the vendor and he's been running his at high RPM for over a year without issues.

[Ron Sutton]

although I agree with the oiling Ron statement but I think badazz81z28 was making a point with the accessory drive system(btw i'm using the dailey dry sump). Its the corvette system from the vendor and he's been running his at high RPM for over a year without issues.

So sorry for mis-speaking.

[BMR Sales]

The unit we find to be the very best for High RPM LS engines on track and/or autocross usage is Here:
http://www.ronsuttonracetechnology.com/catalog/?page=326 (http://www.ronsuttonracetechnology.com/catalog/?page=326)

The reasons why are on that page.

:cheers:

and for looks, the Brushed Aluminum is drop dead sexy!

https://static1.pt-content.com/images/noimg.gif (https://postimages.org/)

https://static1.pt-content.com/images/noimg.gif (https://postimages.org/)

[Ron Sutton]

and for looks, the Brushed Aluminum is drop dead sexy!

https://static1.pt-content.com/images/noimg.gif (https://postimages.org/)

https://static1.pt-content.com/images/noimg.gif (https://postimages.org/)

Hey TC, is your project getting close?

[badazz81z28]

Btw, I also use a gator belt, not the standard one,

[CarlC]

Have you considered removing the hood and mounting a GoPro camera and then running the car through various RPM events to visualize what may be happening? It may be something as simple as adding a idler pulley along one of the belt lengths to get rid of a harmonic.

[130fe]

I would also check pulley alignment. I am currently running the factory C5/Holley stuff, ran great for 10k miles and numerous autoX and street driving. Was doing autoX at Cruising the Coast last year and threw a belt. Everything "looked" fine visually but my factory style balancer was trying to walk off of the crank. It had moved about 1/4" out from where it had been originally. Fixed that and no more problems. What balancer are you running running (corvette, CTS/F body or truck)?