GTM Performance Engineering: VQ37VHR Twin Supercharger System

Nissan370 · 06-07-2012, 06:09 AM

Hey Sam how hard is it to get to that main belt if it goes bad for what ever reason

fuct · 06-07-2012, 08:09 AM

its such a sexy looking system!

Mike@GTM · 06-07-2012, 11:46 AM

Quote:

Originally Posted by Nissan370

Hey Sam how hard is it to get to that main belt if it goes bad for what ever reason

It's no more difficult than normal. The only extra step compared to the factory procedure is removing the two supercharger belts.

Nixlimited · 06-07-2012, 12:41 PM

@GTM - Are you worried at all about belt slip on the two pulleys (with slightly reddish looking center areas) that connect the main accessory belt to the long SC belts? The SC pulleys themselves have what looks like 70+% wrap thanks to the movable tensioners, but the two connecting pulleys appear to have less than 50%.

Mike@GTM · 06-07-2012, 02:05 PM

Quote:

Originally Posted by Nixlimited

@GTM - Are you worried at all about belt slip on the two pulleys (with slightly reddish looking center areas) that connect the main accessory belt to the long SC belts? The SC pulleys themselves have what looks like 70+% wrap thanks to the movable tensioners, but the two connecting pulleys appear to have less than 50%.

Not really. One of the nice things about designing systems in CAD (like we did with this system), is that things like belt wrap can be calculated to tenths of a degree. With that kind of information, things like load profiles can be modeled and calculated. Granted, there are always variables that cannot be accounted for. That's why we do testing and verification in addition to design work.

By the way, how were you able to determine that there is less than 50% belt wrap on those pulleys? I mean, I know Sam takes great pictures and all, but I'm not seeing less than 50% wrap in the pictures myself.

fuct · 06-07-2012, 02:55 PM

i wish the stuff i designed in Autodesk Inventor was as exciting as the stuff yall build. damn you lucrative oil and gas industry!!!! :P

Nixlimited · 06-07-2012, 03:38 PM

Quote:

Originally Posted by Mike@GTM

Not really. One of the nice things about designing systems in CAD (like we did with this system), is that things like belt wrap can be calculated to tenths of a degree. With that kind of information, things like load profiles can be modeled and calculated. Granted, there are always variables that cannot be accounted for. That's why we do testing and verification in addition to design work.

By the way, how were you able to determine that there is less than 50% belt wrap on those pulleys? I mean, I know Sam takes great pictures and all, but I'm not seeing less than 50% wrap in the pictures myself.

Haha, wasn't able to "calculate" at all. Purely going on visual based on the angle the belts are coming off the wheels in this picture:

In fact, it looks like there is more than 50% wrap. However, what seems clear (thanks to Sam's awesome photos) is that relative to the actual SC pulleys, the stacked pulleys have less wrap. With your single SC systems, you do advertise as a feature the large percentage of wrap, which is what got me thinking about it in the first place.

Anyway, don't want to take anything away from what y'all are doing. The work looks top-notch and I am very anxious to see the results.

The Dimer · 06-07-2012, 03:42 PM

Quote:

Originally Posted by Mike@GTM

Not really. One of the nice things about designing systems in CAD (like we did with this system), is that things like belt wrap can be calculated to tenths of a degree. With that kind of information, things like load profiles can be modeled and calculated. Granted, there are always variables that cannot be accounted for. That's why we do testing and verification in addition to design work.

By the way, how were you able to determine that there is less than 50% belt wrap on those pulleys? I mean, I know Sam takes great pictures and all, but I'm not seeing less than 50% wrap in the pictures myself.

I can see what he's talking about. If you look at the pictures, the "red" pulley on the left (which has more belt between it and the supercharger pulley than the other "red" pulley) it looks like it could be close to 50 percent. Granted we don't have the CAD drawings to know exactly, and it could just be from the pictures.

Mike@GTM · 06-07-2012, 04:54 PM

Quote:

Originally Posted by Nixlimited

Haha, wasn't able to "calculate" at all. Purely going on visual based on the angle the belts are coming off the wheels in this picture:

In fact, it looks like there is more than 50% wrap. However, what seems clear (thanks to Sam's awesome photos) is that relative to the actual SC pulleys, the stacked pulleys have less wrap. With your single SC systems, you do advertise as a feature the large percentage of wrap, which is what got me thinking about it in the first place.

Anyway, don't want to take anything away from what y'all are doing. The work looks top-notch and I am very anxious to see the results.

Ah, you're referencing the main serpentine belt wrap percentage on the driven side of the stacked pulley. Sorry, I thought you were referencing one of the other pulleys.

First, there is an idler pulley on both sides of the driven side of the stacked pulleys to get as much wrap around them as possible. Also, the driven side of the stacked pulleys aren't as critical in terms of belt wrap as the supercharger pulley itself. The reason for that is the fact that the stacked pulleys are smaller in diameter than the supercharger pulleys. As such, the input torque that the stacked pulley receives from the main serpentine belt is not as large as the output torque at the supercharger pulley. Remember, pulleys are like gears in the sense that a small pulley driving a larger pulley multiplies the torque at the expense of speed (the larger pulley will generate more torque, but turn slower).

A supercharger system with insufficient belt wrap around the supercharger pulley has a tendency to experience belt slip. As you can see in our pictures, we have once again maximized the amount of belt wrap around the supercharger pulley itself.

Quote:

Originally Posted by The Dimer

I can see what he's talking about. If you look at the pictures, the "red" pulley on the left (which has more belt between it and the supercharger pulley than the other "red" pulley) it looks like it could be close to 50 percent. Granted we don't have the CAD drawings to know exactly, and it could just be from the pictures.

Interestingly, you guys are talking about the same pulley, just different ends of it. The end you are referencing does have more than 50% belt wrap. If testing reveals that it needs more belt wrap, we've already got a solution worked out. Like I said in response to Nixlimited's concern, however, it's not as critical as the belt wrap around the supercharger pulley itself.

The Dimer · 06-07-2012, 05:23 PM

Quote:

Originally Posted by Mike@GTM

Ah, you're referencing the main serpentine belt wrap percentage on the driven side of the stacked pulley. Sorry, I thought you were referencing one of the other pulleys.

First, there is an idler pulley on both sides of the driven side of the stacked pulleys to get as much wrap around them as possible. Also, the driven side of the stacked pulleys aren't as critical in terms of belt wrap as the supercharger pulley itself. The reason for that is the fact that the stacked pulleys are smaller in diameter than the supercharger pulleys. As such, the input torque that the stacked pulley receives from the main serpentine belt is not as large as the output torque at the supercharger pulley. Remember, pulleys are like gears in the sense that a small pulley driving a larger pulley multiplies the torque at the expense of speed (the larger pulley will generate more torque, but turn slower).

A supercharger system with insufficient belt wrap around the supercharger pulley has a tendency to experience belt slip. As you can see in our pictures, we have once again maximized the amount of belt wrap around the supercharger pulley itself.

Interestingly, you guys are talking about the same pulley, just different ends of it. The end you are referencing does have more than 50% belt wrap. If testing reveals that it needs more belt wrap, we've already got a solution worked out. Like I said in response to Nixlimited's concern, however, it's not as critical as the belt wrap around the supercharger pulley itself.

Good to know. Thanks for taking the time to explain everything.

wheee! · 06-13-2012, 07:30 AM

^ reported

georgesc · 06-14-2012, 08:32 PM

I'm throwing money at the screen but nothing is happening

Also, next up, a Super and Turbo combo,
That would be sweet, but unlikely to happen

KaienZ34 · 06-14-2012, 08:50 PM

Would be super cool, but most likely a tuning nightmare.

scth83 · 07-13-2012, 01:05 PM

Sam, do you have the dyno result yet?
I'm very interested this twin sc kit, what is the price tag, please pm me.

VSS370z · 07-13-2012, 02:32 PM

I also want to know the price of this kit!

06-07-2012, 06:09 AM	#166 (permalink)
Nissan370 Enthusiast Member Join Date: Feb 2011 Location: Baltimore Posts: 431 Drives: 2009 ST BLK 370Z Rep Power: 14	Hey Sam how hard is it to get to that main belt if it goes bad for what ever reason __________________ 370z vsr motorsports single turbo/built motor 9.1cr 525rwhp/450rwtq @ 10.5psi (stock maf maxed out)

06-07-2012, 12:41 PM	#169 (permalink)
Nixlimited A True Z Fanatic Join Date: Aug 2009 Location: San Diego Posts: 1,235 Drives: 15 GT-R / 11 Prius Rep Power: 25	@GTM - Are you worried at all about belt slip on the two pulleys (with slightly reddish looking center areas) that connect the main accessory belt to the long SC belts? The SC pulleys themselves have what looks like 70+% wrap thanks to the movable tensioners, but the two connecting pulleys appear to have less than 50%. __________________ Car Sold! Pleasure being a part of the Z community. New ride: 2015 GT-R - 647 WHP / 641 WTQ (e85) & 543 WHP / 519 WTQ (91)

06-13-2012, 07:30 AM	#176 (permalink)
wheee! A True Z Fanatic Join Date: Sep 2009 Location: Mod Capital of Canada Age: 57 Posts: 7,354 Drives: cars. lots of cars. Rep Power: 40181	^ reported __________________ H&R / Stillen / Berk / HKS / Swift / Michelin / UpRev / SPC / Amuse Rep / Seibon / Fringe XVO / TWM / more... My Journal

06-14-2012, 08:50 PM	#178 (permalink)
KaienZ34 A True Z Fanatic Join Date: Oct 2009 Location: LA. not L.a. Posts: 21,652 Drives: Z34 Tour/Sport Rep Power: 177	Would be super cool, but most likely a tuning nightmare. __________________ *"These Violent Delights Have Violent Ends"* http://www.the370z.com/members/kaienz34-albums-z34.html

07-13-2012, 02:32 PM	#180 (permalink)
VSS370z Enthusiast Member Join Date: Apr 2012 Location: Puerto Rico Posts: 380 Drives: 09 Nissan 370z CY M6 Rep Power: 13	I also want to know the price of this kit! Last edited by VSS370z; 07-13-2012 at 02:35 PM.

06-07-2012, 08:09 AM	#167 (permalink)
fuct A True Z Fanatic Join Date: May 2009 Location: Sugar Land Posts: 3,692 Drives: 97' Ranger :) Rep Power: 23	its such a sexy looking system!

06-07-2012, 02:55 PM	#171 (permalink)
fuct A True Z Fanatic Join Date: May 2009 Location: Sugar Land Posts: 3,692 Drives: 97' Ranger :) Rep Power: 23	i wish the stuff i designed in Autodesk Inventor was as exciting as the stuff yall build. damn you lucrative oil and gas industry!!!! :P

06-14-2012, 08:32 PM	#177 (permalink)
georgesc Base Member Join Date: May 2012 Location: Australia Posts: 5 Drives: 11 Nissan 370 SW AT Rep Power: 12	I'm throwing money at the screen but nothing is happening Also, next up, a Super and Turbo combo, That would be sweet, but unlikely to happen

07-13-2012, 01:05 PM	#179 (permalink)
scth83 Base Member Join Date: Mar 2010 Location: HK Posts: 18 Drives: 10 Nissan 370Z PG M6 Rep Power: 15	Sam, do you have the dyno result yet? I'm very interested this twin sc kit, what is the price tag, please pm me.

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