Generation IV Internal Engine - GM Gen IV VVT Performance Gains

Since its release, the benefits of GM Gen IV Variable Valve Timing (VVT) technology have been unknown to the performance aftermarket. Mast Motorsports recently conducted testing during the development of our L92 turnkey crate engine package to determine the performance gains of the GM Gen IV cam phasing capabilities. We would like to share these results publicly as we develop this technology for aftermarket applications. The test engine was a stock L92 with a L76 intake manifold package, 90mm drive-by-wire throttle body, 1-3/4 inch primary long tube headers, and 87 octane fuel on our SuperFlow SF-902 NSCR engineering grade dyno. The same stock camshaft was used in all tests shown below. The tests shown below were all performed with the same calibration; therefore, the tests with a stationary cam were slightly rich in places due to the inherent lower VE of no variable valve timing. However, the differences in the engine performance are still valid for illustrating the drastic gains that can be made using VVT.

The data in the graphs below compares the performance of the camshaft in a stationary position to the performance of our crate engine package calibration which phases the camshaft throughout the RPM range. The first graph shows the performance of the camshaft phased at -5 degrees (the camshaft position to produce peak torque on our calibration). This data is laid over our power curve and highlights the gains made in the upper RPM range due to VVT.

http://i205.photobucket.com/albums/bb186/MastMotorsports/L92withVVTvsL92withNoVVTat-5CAD.jpg

The second graph shows the performance of the camshaft phased at -18 degrees (the camshaft position to produce peak power on our calibration). This data is laid over our power curve and highlights the gains made in the lower RPM range due to VVT.

http://i205.photobucket.com/albums/bb186/MastMotorsports/L92withVVTvsL92withNoVVTat-18CAD.jpg

Since the GM Gen IV engines have been released, the relevance of VVT on LS series performance applications has been unknown. As you can see, the data speaks for itself. Phasing the camshaft produces more area under the power curve throughout the entire RPM range compared to a camshaft with a stationary installed center line. We are going to continue to conducting testing while finishing the development of our Phaser Series camshafts which are designed around VVT technology. In the coming weeks we will be developing our LSX block based VVT 454X engine. We are expecting some very solid numbers with these cams and VVT and are excited about bringing this technology to the aftermarket with our crate engine packages using our M-90 ECM.

Shaun
Mast Motorsports
www.mastmotorsports.com

This is promising stuff Shaun. The upcoming Viper will have VVT from the factory (exhaust side only) so big cube motors are finally going that direction. When you think of what the Japanese can do with smaller displacement engines because of VVT, just think of what can be done with 6+ liters and still maintain every day driveability.

GOOD info!

Did you do any test with 93 Octane???

:lurk:

So as RPM builds, you're gradually retarding the cam ICL, correct? This results in a later IVC, and better cylinder filling at high rpm?

But at the same time, EVO is getting later, which doesn't exactly help your cause at high RPM. Really, we need separate intake and exhaust cams for this technology to show itself to the optimum ... but it's still very useful with just a single cam.

"Wait until VTEC kicks in on my 454" :jest:

Cool stuff.

That's good information. What effects does VVT have on tuning?

Very interesting stuff!! Just think of what the Honda guys will say?! HAHAHAHA!!!

MastMotorsports, you are in nac? man if i would have known this. i go to SFA and got the hook up with ag shop and custom machine shop there. you should have called me up. i would have loved to be in on this. dude i might know who you are hook it up man.

this data is great.

great work guys!

everyone has a go at the honda guys but they have moved the game on! its clear to see the benifits of what can be achived. but nice to see some comparisions with bigger cams in there.


Chris.

In the ECU for the VVT motors can you set the injector pulse to follow the VVT settings.
IE if you retard the cam can you delay the start point of the injector pulse and delay the stop point.

This would work best for vehicles that have LT where the cat's do not need raw fuel to keep them cool (ls2's Dump Fuel at Cut Off).

I figure you can get the gas mileage to increase a little if you can keep the injector pulse set to start at the closing of the exhaust valve and injector pulse stop point to just before the intake valve closes.

An Idea for your testing...
Start the motor with the camshaft phased at -18 degrees (max low end torque setting). Set the ECU to adjust the cam just prior to the peak torque level to retard to say -15 then -12 then -9 then -5 at 500 rpm intervals or so.

I'll have to look at your torque curves when I get home (blocked at work via proxy server).

My idea is to draw out the torque's peak through about 1500rpm.... Instead of having the torque curve shoot up then fall off (non vvt motor). Have it shoot up then flatten out.

I'll look at the graphs when I get home.

Very nice Shaun

Robin

my jeep needs one of these.;)


p.s.- let me know if that regulator works.

http://forums.streetfire.net/attachment.php?attachmentid=9126&stc=1

in a V8. promising stuff.

Correct, we do retard the cam as RPM builds. Here is the power curve for 93 octane fuel. Also thought that I should mention that the stock cam is only .500 lift, so our L92 HO should be interesting.

http://i205.photobucket.com/albums/bb186/MastMotorsports/StockL92CarIntake93OctanePowerCurve.jpg

Shaun
www.mastmotorsports.com

Bump.

440 hp through a stock cam, nice!
How is the 454 coming?

Shaun,

What WOT spark timing are you running the stock L92 at with 87 octane and VVT active? With 93 octane? Thanks for sharing your results with us on your VVT developements.

Ron

this is awsome...the technology thats allowed the 4 cyls to keep up is finally coming to us...I wonder what their excuses will be then. Awsome work.

Will the VVT work on a Gen III (i.e. retrofit), or is just available for Gen IV motors?

Will the VVT work on a Gen III (i.e. retrofit), or is just available for Gen IV motors?

At this point, we are only making this available for Gen IV engines. However, I do believe it is possible.

The LSX block based 454X VVT is done and we are developing the VVT for this application on the dyno. No numbers yet, but coming soon.

Shaun
www.mastmotorsports.com

Shaun,

Is it possible to measure the part throttle changes in power and torque as well as the fuel effiency? Are you guys working on the VVT in part throttle situations as well? I think the part throttle portions of the tune are where some big gains in performance, efficiency and driveability can be made with VVT.

This is really good info. I can't wait to see how this evolves.

At this point, we are only making this available for Gen IV engines. However, I do believe it is possible.

The LSX block based 454X VVT is done and we are developing the VVT for this application on the dyno. No numbers yet, but coming soon.

Shaun
www.mastmotorsports.com

i think that might be intresting! ;)

have you thought of doing this cam aranegment with boost??? would be interesting to see just what advanvtages this could bring. i think it would be quite alot! ;)

Chris.

Shaun,

Is it possible to measure the part throttle changes in power and torque as well as the fuel effiency? Are you guys working on the VVT in part throttle situations as well? I think the part throttle portions of the tune are where some big gains in performance, efficiency and driveability can be made with VVT.

Yes, we are mapping the camshaft timing over the entire operating range of our engine. The gains that we have seen (especially in the lower RPM range) have been impressive. I will post more results as soon as we get them.

Shaun
www.mastmotorsports.com

Yes, we are mapping the camshaft timing over the entire operating range of our engine. The gains that we have seen (especially in the lower RPM range) have been impressive. I will post more results as soon as we get them.

Great news! Keep us informed of your progress.

Thanks for sharing the info .. :thumb:

bump :D

I have an 08 Silverado with the VortecMAX VVT 6.0 on order. Does the stock PCM support altering the cam timing? I use EFILive. I'll check on that web site to see if it is supported.

Any updates on the 454 VVT?

Bump for a very interesting topic

do you sell just the vvt performance cam i have a L92 engine just want to upgrade the cam for some more power

do you sell just the vvt performance cam i have a L92 engine just want to upgrade the cam for some more power

nycblazer,

We only sell our VVT cams with our L92 crate engine packages.

Shaun
www.mastmotorsports.com

is there anyone selling vvt cams

How hard would it be to convert a 2005 GTO (Gen IV LS2 with 24x crank gear) to the L92 HO with VVT?
Can the existing wiring harness be re-used and just replace the M34 ECU with the M90?

How much RWHP in does the L92 HO deliver?

Any testing on installing VVT onto the 5.3L's with just AFM?
My Mom's vehicle is a 2006 GMC Envoy XL Denali with AFM.
I'ld like to give it a little more power, and a VVT+AFM cam (along with a spring upgrade and headers) would really wake that motor up.

Just a thought.

is there anyone selling vvt cams

I am not aware of anyone else with VVT camshafts.

How hard would it be to convert a 2005 GTO (Gen IV LS2 with 24x crank gear) to the L92 HO with VVT?
Can the existing wiring harness be re-used and just replace the M34 ECU with the M90?

How much RWHP in does the L92 HO deliver?

Any testing on installing VVT onto the 5.3L's with just AFM?
My Mom's vehicle is a 2006 GMC Envoy XL Denali with AFM.
I'ld like to give it a little more power, and a VVT+AFM cam (along with a spring upgrade and headers) would really wake that motor up.

Just a thought.

It would be the same as an engine swap using a stand alone controller. We put an L92 HO in our 2000 T/A shop car. It was a very simple swap. The engine comes with its own wiring harness to work with the M-90. The L92 HO makes 540 HP at the flywheel. We haven't done a chassis dyno pull with that car since we finished it. It has an L92 HO, TH400 with a 3200 stall, 4.30 gears, and an upgraded suspension. I will tell you that it is a 3200-3400 Lb. car that goes 10.90s-11.00s@122-123 really consistently. We have not done any testing on the 5.3L.

Shaun
www.mastmotorsports.com