GTM 370z supercharger 550bhp/400 ft of Torque: The Masterpiece

Lug · 03-15-2011, 11:54 AM

Quote:

Originally Posted by Staples

I've posted an explanation on another thread, can't find it... here's a brief copied and pasted explanation.

The VVEL system in our cars and extremely aggressive at about a 300 cam duration;

Valve Overlap

"The portion of the operating cycle of a reciprocating engine in which, when the piston is passing TDC (top dead center) on the exhaust stroke, both the intake and exhaust valves are open. Valve overlap increases the efficiency of the engine operation by allowing the low pressure caused by the exhaust gases leaving the cylinder to help the fresh charge of fuel-air mixture in the induction system to start moving into the engine."

When you're pushing so much air into a car (forced induction) with an aggressive cam - there's air that isn't going to be used and is just going to pushed out of the motor and wasted because both the intake / exhaust valves are open at the same-time. Drop the cam duration, you'll have more time between the valve overlap process so when the air enters the head it will give the bottom end enough time to use that air for the combustion process, building more psi, creating more power.

Let me know if there's anything I'm incorrect about, but that's what I've gathered.

So in essence a more free flowing exhaust system could effect SC performance if you are using the VVEL system. That could explain some weired results we've seen in SC'ed cars so far.

BLM · 03-15-2011, 12:00 PM

So then, LTH/TP + SC + VVEL <<< LTH/TP + SC + 'cracked' VVEL??

I get it now. These were tested with stock cats. More resistance to exhaust flow = more time in combustion chamber = best you can do with SC + VVEL. Sorry I had to write that out. Went to an engineering school but was not an engineer. Pretty much exactly what Mike said post #2.

Staples · 03-15-2011, 09:43 PM

Quote:

Originally Posted by Lug

So in essence a more free flowing exhaust system could effect SC performance if you are using the VVEL system. That could explain some weired results we've seen in SC'ed cars so far.

The supercharger runs off of backpressure, that's why more boost / power was made with the stock cats rather then longtube headers, reduce backpressure lose boost.

1slow370 · 03-16-2011, 04:47 AM

they don't run off back pressure, to much is still a bad thing as then you start to trap exhaust in the cylinder instead of more fresh air mixture. the breathing mechanics are complicated. basically what you want is enough duration and lift on the exhaust that the engine pumps out most of the exhaust gasses, but on our cars which are tuned for n/a the valve overlap between the exhaust and intake valves allows the now compressed air charge to escape with the exhaust before the valve closes. all that is really needed is to bump the intake cam timing backward to reduce the overlap but with vvel you have to do both or nothing or else you risk the valves hitting the piston due to the high lift.

Z eliminator · 09-01-2011, 09:14 AM

One "off custom intake ".
how can you claim those #'s with that intake, as the average customer will not have one on his car.
How much more did it make VS the stock intake ?

Lug · 09-01-2011, 01:44 PM

Quote:

Originally Posted by Z eliminator

One "off custom intake ".
how can you claim those #'s with that intake, as the average customer will not have one on his car.
How much more did it make VS the stock intake ?

Read post #2

RCZ · 09-01-2011, 03:05 PM

Quote:

Originally Posted by Z eliminator

One "off custom intake ".
how can you claim those #'s with that intake, as the average customer will not have one on his car.
How much more did it make VS the stock intake ?

wow, someones neurons are firing. I thought all hope was lost.

NYBladeZ · 09-01-2011, 03:52 PM

In the end of it all, the real gains from F.I. be it SC or TT on the VQ37 will not be recognized until VVEL is cracked its that simple. When you are forced to deal with stock cats due to VVEL not allowing you to fine tune timing and fully utilized the compressed air you're just banging around fixing everything else except the real issue. Damn thing is that VVEL seems like a tuning rubix cube that no one has figured out yet but everyone says they are working on.

Staples · 09-01-2011, 11:48 PM

Quote:

Originally Posted by NYBladeZ

In the end of it all, the real gains from F.I. be it SC or TT on the VQ37 will not be recognized until VVEL is cracked its that simple. When you are forced to deal with stock cats due to VVEL not allowing you to fine tune timing and fully utilized the compressed air you're just banging around fixing everything else except the real issue. Damn thing is that VVEL seems like a tuning rubix cube that no one has figured out yet but everyone says they are working on.

Until then... you have to find ways around it, safely.

NYBladeZ · 09-04-2011, 10:29 PM

^^that's a bandaid solution. Fact of the matter is that none of us really know what the VQ37 is capable of until VVEL is cracked. This is a guess but since its going to take a lot of r&d and probably not be something as simple as an UpRev add on I'd guess its going to be expensive. Kind of sucks for guys like me who already bought the uprev and then have to go back and get either an upgraded uprev if that turns out to be the solution or pony up for an additional tuning solution and/or hardware all together.

Z eliminator · 09-11-2011, 10:05 AM

GTM just shipped my stage 2.
Will be here in about 10 days ( has to clear customs ).
the wait is over.

Nixlimited · 09-11-2011, 11:27 AM

Quote:

Originally Posted by Z eliminator

GTM just shipped my stage 2.
Will be here in about 10 days ( has to clear customs ).
the wait is over.

Congrats dude. Looking forward to finally seeing what your car will put down at the strip.

Z eliminator · 09-25-2011, 06:12 PM

Just started reading the shipping manufest with my GTM stage 2 kit and it says
super charger back ordered and not shipped.
SAM WHAT IS GOING ON.

PLEASE TELL ME WHY !!!!!!!!

W.O.W. 370Z · 09-25-2011, 06:45 PM

Quote:

Originally Posted by Z eliminator

Just started reading the shipping manufest with my GTM stage 2 kit and it says
super charger back ordered and not shipped.
SAM WHAT IS GOING ON.

PLEASE TELL ME WHY !!!!!!!!

I thought you got it already.

NeverBoneStck · 09-25-2011, 08:59 PM

Quote:

Originally Posted by Z eliminator

Just started reading the shipping manufest with my GTM stage 2 kit and it says
super charger back ordered and not shipped.
SAM WHAT IS GOING ON.

PLEASE TELL ME WHY !!!!!!!!

Ouch ... That is so cruel for GTM to do that. They could of least gave u a call or email. You know ... That communication thing ....

03-15-2011, 12:00 PM	#2 (permalink)
BLM Enthusiast Member Join Date: Feb 2011 Location: NJ Posts: 342 Drives: 2011 Silver M6 sport Rep Power: 15	So then, LTH/TP + SC + VVEL <<< LTH/TP + SC + 'cracked' VVEL?? I get it now. These were tested with stock cats. More resistance to exhaust flow = more time in combustion chamber = best you can do with SC + VVEL. Sorry I had to write that out. Went to an engineering school but was not an engineer. Pretty much exactly what Mike said post #2. __________________ K&N // GTM // BERK Last edited by BLM; 03-15-2011 at 12:03 PM.

03-16-2011, 04:47 AM	#4 (permalink)
1slow370 A True Z Fanatic Join Date: Aug 2009 Location: In the D Posts: 3,732 Drives: v8 74 260z ;) Rep Power: 7251	they don't run off back pressure, to much is still a bad thing as then you start to trap exhaust in the cylinder instead of more fresh air mixture. the breathing mechanics are complicated. basically what you want is enough duration and lift on the exhaust that the engine pumps out most of the exhaust gasses, but on our cars which are tuned for n/a the valve overlap between the exhaust and intake valves allows the now compressed air charge to escape with the exhaust before the valve closes. all that is really needed is to bump the intake cam timing backward to reduce the overlap but with vvel you have to do both or nothing or else you risk the valves hitting the piston due to the high lift. __________________ ANSWER PRICE LIST Answers - - - - - - - - - - - - - - - - $0.75 Answers (requiring thought) - - - - $1.25 Answers (correct) - - - - - - - - - - $12.50

09-01-2011, 09:14 AM	#5 (permalink)
Z eliminator A True Z Fanatic Join Date: Jul 2009 Location: Ontario Canada Posts: 1,659 Drives: 370 Z 7AT Sports Rep Power: 19	One "off custom intake ". how can you claim those #'s with that intake, as the average customer will not have one on his car. How much more did it make VS the stock intake ? __________________ 12.343 @114.14 . 4.5 stroker motor is now being built. Dec 1 2015.

09-01-2011, 03:52 PM	#8 (permalink)
NYBladeZ A True Z Fanatic Join Date: Apr 2009 Location: New York Posts: 2,158 Drives: Lotus Exige S Rep Power: 21	In the end of it all, the real gains from F.I. be it SC or TT on the VQ37 will not be recognized until VVEL is cracked its that simple. When you are forced to deal with stock cats due to VVEL not allowing you to fine tune timing and fully utilized the compressed air you're just banging around fixing everything else except the real issue. Damn thing is that VVEL seems like a tuning rubix cube that no one has figured out yet but everyone says they are working on. __________________ 2009 Carbon Fiber/Red 370z aka Trish: Sports Package, Meisterschaft full catback, Fast Intentions Longtube Headers, Injen Long Tube Intakes, UpRev Tune: Sold 2008 Lotus Exige S Club Racer aka Bella, always leaves me smiling

09-04-2011, 10:29 PM	#10 (permalink)
NYBladeZ A True Z Fanatic Join Date: Apr 2009 Location: New York Posts: 2,158 Drives: Lotus Exige S Rep Power: 21	^^that's a bandaid solution. Fact of the matter is that none of us really know what the VQ37 is capable of until VVEL is cracked. This is a guess but since its going to take a lot of r&d and probably not be something as simple as an UpRev add on I'd guess its going to be expensive. Kind of sucks for guys like me who already bought the uprev and then have to go back and get either an upgraded uprev if that turns out to be the solution or pony up for an additional tuning solution and/or hardware all together. __________________ 2009 Carbon Fiber/Red 370z aka Trish: Sports Package, Meisterschaft full catback, Fast Intentions Longtube Headers, Injen Long Tube Intakes, UpRev Tune: Sold 2008 Lotus Exige S Club Racer aka Bella, always leaves me smiling

09-11-2011, 10:05 AM	#11 (permalink)
Z eliminator A True Z Fanatic Join Date: Jul 2009 Location: Ontario Canada Posts: 1,659 Drives: 370 Z 7AT Sports Rep Power: 19	GTM just shipped my stage 2. Will be here in about 10 days ( has to clear customs ). the wait is over. __________________ 12.343 @114.14 . 4.5 stroker motor is now being built. Dec 1 2015.

09-25-2011, 06:12 PM	#13 (permalink)
Z eliminator A True Z Fanatic Join Date: Jul 2009 Location: Ontario Canada Posts: 1,659 Drives: 370 Z 7AT Sports Rep Power: 19	Just started reading the shipping manufest with my GTM stage 2 kit and it says super charger back ordered and not shipped. SAM WHAT IS GOING ON. PLEASE TELL ME WHY !!!!!!!! __________________ 12.343 @114.14 . 4.5 stroker motor is now being built. Dec 1 2015.

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