Vvt & Boost

[JJhamitlon 6]

I'm trying to learn how this all works together especially considering my plans to go with a blower. Please bare with me as I learn!

So I understand VVT can advance or retard the cam quite a bit (20+ advance?), how is the timing controlled during boost, is this all part of the tunning software, does the PCM in these have that much control and the speed in which to control that much variance during boosted applications or is the amount reduced/ limited by

tuning?

Also, guys that are running stroker motors from mild to wild, are you guys staying with VVT or dropping it all together?

I can see the advantages to VVT but I can also see the dangers with a boosted (any performance combination for that matter) application. I know it's all been done and it's under control, I'd just like to understand a bit more for my own benefit. From what little I do know, it's obvious whomever does the tuning on these motors better know what they are doing, and it really shows how far behind the curve I've dropped over the years. This isn't like twisting a distributor and turning up the fuel regulator...

Thanks

[otogi40 4]

I think MDS is more of an issue for forced induction than VVT. Your tuner will probably suggest turning it off in the tune.

Sent from my VK815 using Tapatalk

[rdrdr90 35]

MDS is no issue, it is turned off in the tune. VVT is nowhere near the issue it was a few years ago, tuning has come a looooong way. Even then, VVT was more of an issue when trying to upgrade the cam, was not an issue with boost.

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[Speedy 247]

It's almost all gonna be VVT anymore. The 6.1 was the last engine that wasn't VVT and those are getting a bit scarce.

Mine's a stroker and VVT and boosted. Runs great. Just make sure you use a reputable tuner. Mike @ OST Dyno tunes mine. HemiTuner is another excellent tuner as well.

[Linda's FF 34]

http://modernmoparforum.com/topic/11570-1000rwhp-2009-vvt-challenger-rt-with-single-power-adder-a-reason-to-keep-vvt/

When Josh posts in the thread he has learned a ton about vvt and tuning.......that is 100% truth. And he continues to work on vvt with excellent results.

Josh has the Fastest record setting Hell cats coming out of the HHP corral.

Hell Cats are vvt

You may want to give HHP a call.

For the quickest response, please call the shop 888-894-1115

For sales questions use extension 306 for Greg.

For tech questions use 302 for Bruce.

For tuning questions use 301 for Josh.

http://www.hhpracing.com/

Linda

[JJhamitlon 6]

http://modernmoparforum.com/topic/11570-1000rwhp-2009-vvt-challenger-rt-with-single-power-adder-a-reason-to-keep-vvt/

When Josh posts in the thread he has learned a ton about vvt and tuning.......that is 100% truth. And he continues to work on vvt with excellent results.

Josh has the Fastest record setting Hell cats coming out of the HHP corral.

Hell Cats are vvt

You may want to give HHP a call.

For the quickest response, please call the shop 888-894-1115

For sales questions use extension 306 for Greg.

For tech questions use 302 for Bruce.

For tuning questions use 301 for Josh.http://www.hhpracing.com/

Linda

Thanks, interesting read and really enjoyed it.....but didn't answer my questions about VVT. They didn't need VVT to make the power, didn't say it helped make it easier to make the power.. And I doubt they are driving the car on the streets so it's not about saving fuel. So what is VVT actually do for us in the end especially when it comes to Boost.

I hate to call them while they are trying to work, to request a free education and if imagine they are really busy right now with racing going on, Arrignton has me on the back burner with questions I've been asking for month now about work I want to pay to have done, I figure for the same reasons the current events

[Speedy 247]

VVT allows you to have an easy car to drive down low in the RPM range and more power in the mid and upper RPM ranges. Non VVT seems dead as all current Mopar V8 motors are VVT.

Pretty easy to Google VVT and get a nice education.

[JJhamitlon 6]

VVT allows you to have an easy car to drive down low in the RPM range and more power in the mid and upper RPM ranges. Non VVT seems dead as all current Mopar V8 motors are VVT.

Pretty easy to Google VVT and get a nice education.

( Google ) Will do, I remembero correctly your running a stroker with a blower and VVT also (?) In regards to control of timing with VVT and boost, the ECM is telling the phaser to keep the cam at the right position? Or this, in a simple version, for power in the higher rpms you advance a cam, if you want it lower down the rpms you would retard the cam...VVT is doing this real time and doing it at the right time for NA, but with boost advancing the cam could be detrimental...so what's keeping this in check...the tune? If so, tuners have the ability to adjust the advancement or retardation of the cam simply by tables? If that's true, why do we need cam locks for big cam installs? <<That's basically what I don't understand, in one application ( NA ) you must install something that limits cam travel, but with boost you can do this with tuning? Is the boosted applications not as detrimental... 23 degree advanced with 12 psi at 6k rpms is ok??

Am I way off base on how this works?

[Speedy 247]

I'm not an expert on the technology. AJ (Hemituner) or Erik (Hemi31) likely are and can give more details. Having said that I'll tell you what I know and my personal experience.

Yes, my car has a 6.0L stroker based on a VVT 5.7 with a baby regrind VVT cam, and a Magnuson blower.

You're close on how it all works.

As you know the cam controls valves opening and closing and to what duration and extent. VVT cams have lobes that aren't all machined the same and as it moves through the RPM range it changes dynamically these valve characteristics. This is how you can have a nice driving car at lower RPM and more power in the mid and upper ranges rather than a car that's hard to reverse or put around parking lots in with the compromise of more power up top.

The locks are there to prevent the pistons coming in contact with the valves. You can move the VVT cam TOO far and hold the valves open TOO long and bad things happen when hard parts meet. Only recently has it been determined that VVT timing can be controlled in a tune, but you still want the lock as a safety to insure you never have piston to valve contact. Mike@OST tunes my car and a year or so ago he was working with SteveO's car (on this forum) and found a table in the tune and started making adjustments and taking notes, and he realized it was adjusting the cam timing through VVT. He worked with Diablo and did some further enhancements, sent me a tune to "test" and sure enough I picked up about 25RWHP with his changes. He said he could move it more, but thought we should call it good as we didn't have bench testing to see where the limit would be.

Tuning VVT is still not lickity split easy and I've not seen tuners willing to do the Comp VVT cams without having the car on site for a few days to get it right ($$$). This made ROI not worth it for me, so I've just left mine alone. If I were having the motor built today, I would opt for the Comp cam though and work it in to the package.

[sharkcohen 60]

I've got a built Apache 392 with a Hellcat camshaft and an Edelbrock E-force blower. I don't know how much more lift the Hellcat cam has compared to the stock Apache cam, but I don't have a cam lock. It's working great. Long block assembled and tuned by AJ.

[Speedy 247]

What kinda power did it make? Had it to the track? I've been curious how a Hellcat cam would work on a blown vvt car.

[JJhamitlon 6]

Thank you speedy, that's seriously interesting. I look forward to learning more about this.

Also want to hear more about the Hell Cat cam, should make a good blower cam! Is the HC VVT??

[Micah@OST 13]

An older thread and we've learned a lot since but still a very good read and very applicable.

http://modernmoparforum.com/topic/13312-to-vvt-or-not-to-vvt-that-is-the-question/

What's more is that VVT has more of a positive effect on blower cars than it does on NA. So if you are planning a blower build with VVT, don't get a cam lock! You'll be leaving a lot of power on the table. And to answer one of your original questions, yes through the tuning software the cam can be moved back and forth at will quickly enough to not be detrimental at WOT.

[sharkcohen 60]

What kinda power did it make? Had it to the track? I've been curious how a Hellcat cam would work on a blown vvt car.

706 to the wheels. I haven't had it at the track yet, but I plan to.

[JJhamitlon 6]

Thanks guys this really helped me get an idea of what's going on, really appreciate it. I know I'm should be only concerned with paying for the work but I can't help but to want to ( or attempt ) understand a certain amount of what's going on.

[Speedy 247]

706 to the wheels. I haven't had it at the track yet, but I plan to.

That's stout. How much boost?

Thanks guys this really helped me get an idea of what's going on, really appreciate it. I know I'm should be only concerned with paying for the work but I can't help but to want to ( or attempt ) understand a certain amount of what's going on.

Nothing at all wrong with that. If you're going to own a modified car it's best to have some understanding about how it works.

[sharkcohen 60]

That's stout. How much boost?

10 psi.

[mopar27028 1]

What kinda power did it make? Had it to the track? I've been curious how a Hellcat cam would work on a blown vvt car.

My build used the Hellcat shortblock + cam, dyno was 658whp. Finally made it to my 1/8mile track. ran 7.208 @104.4 with 1.766 60ft.