shrapnel

First post here. I have a 09 Silverado with the LY5 and 4L60E. I've done your basic stuff to it - AFE CAI, BBP premium tune and magnaflow muffler. She put down 280 rwhp on a mustang dyno last year. She runs pretty good but she's starting to fall behind with the 6+ spd trannys and turbo offerings coming from the factory these days, it has me wanting to do more now. In my quest for more power, I am looking into converting to VVT as the truck is heavy. I would like to take advantage of a flatter torque curve and have less low end torque loss that generally comes with a more aggressive cam.

Just about everything I have learned about VVT has been from this hot rod article:
http://www.hotrod.com/articles/hrdp-...formance-test/

I have found that info out there has been otherwise lacking because of the "stick to what you know" element is pretty common in the world of performance cars and most info out there on VVT is about getting rid of it and not taking advantage of what it has to offer, like those that ditch EFI to run a carb...

TSP, while not the first to dive into VVT exploration, seems to be today's leader on that front. From what I can tell, Mast Motorsports seems to have given up. TSP's activity here is what brought me to ask these questions here. I know I could just call them up but I am looking to hopefully tap a broader knowledge base here. When you talk to a salesperson, you run the risk of being fed biased info to try to suck you into a sale.

So onto the questions.....

Can I run a VVT cam in my Gen IV non-VVT engine? Debating just doing the cam swap now and when I get the rest of the VVT equipment and install it, it is just a matter of tuning the VVT instead of having to buy two cams with the same specs. I would think I could but it seems like all the VVT delete kits out there switch to the old 3-bolt style cam so it has me wondering (I'm pretty sure my LY5 has a 1-bolt cam).

The hot rod article lists $1900 worth of stuff to swap to VVT. No way am I paying that much. I figure I could get everything off a 2010-2013 VVT truck from a junkyard for about $200 give or take. How difficult would it be to get the harness to work with a 4-spd?

What springs are you running? I'd like to run a cam with .600 lift using the PSI 1511 springs. The truck is my daily so I would prefer to stick with beehives rather than run duals.

The hot rod article says the VVT systems starts losing control of the cam phaser above 5k rpms when open spring pressure exceeds 380 lbs. The 1511s have open spring pressure of 370 lbs. Any idea what I can rev to with those springs then?

Anything else I should know about VVT?

Thanks.

07NBSChevy

iTrader: (1)

You will need to cut valve reliefs into the pistons or the valves will hit. All 2010-2013 VVT 5.3s have reliefs cut into them for this reason. No way around that.

It is a pretty simple swap but not worth it in my opinion. I have a 2013 Silverado with the VVT 5.3/6-Speed, my company work truck. I had issues with the VVT Actuator and had it turned off in a tune. I didn't notice to much of a difference, I lost a tad bit of acceleration under light throttle up to 2,400 rpm, but that is it.

You can use a engine harness from a 2010-2013 Silverado 4.8L V8 which will have the 4-Speed 4L60E. It has VVT but does not have AFM/DOD, which you should have tuned out regardless. You will need to use the Actuator that came off the same vehicle as the Cam. There are 2 different ones matched to the cam. All 2007.5+ Silverados have a Single Bolt cam.

I heard at one point MAST sold a kit with harness to add VVT to an LS engine, it was around $1,700.

Now VVT will not gain you any power, it will only lower the Torque Curve from 1,600-2,400 rpm. Above that there is no difference.

So you will need;
-Pistons from a VVT 5.3 or you have your pistons flycut.
-Cam from VVT 5.3
-Timing Cover with matching VVT Actuator from same vehicle as cam, Cam Sensor, and short little harness
-An engine harness that works with a VVT engine
-Reprogram your ECM or reprogram the L20 4.8L ECM for a 5.3. I dont know if a 2007.5-2009 ECM will work with VVT.

If you ever decide to do a aftermarket cam swap, or do any boost, you will have to remove VVT anyways. I would just regear your truck, 4.10's with stock 31.6" Tires works amazing, and do a cam swap such as a BTR Truck Stage 2. I use the BTR cam and didn't lose any lowend and above 2,400 RPM it pulls hard. I built my truck for towing my 7,000 lb travel trailer and what a difference just the gears made, let alone a cam with ported heads. Bumping up your compression from 9.9:1 (Which is what yours has) to 10.5:1 to 11:1 will gain lowend as well.

Profire

Here are some cams that should work with VVT
https://www.summitracing.com/search/...-vvt-camshafts

pantera_efi

iTrader: (1)

Hi Shapnel, GOOD Tech, you are CORRECT.

MY customers REQUIRE good torque AND HP in the BAJA races.
THUS VVT.
The result of the BAD VVT "tech' may allow a low cost purchase of the needed items. (Craigs, E-bay, etc. OR my stock)
1. GOOD Choice of the PSI-1511ML springs as they ARE my spec.
2. Crower VVT "regrind" with my/your core. (VVT's are best with MILD lobes)
3. MY or Comp or ??? VVT motor Travel Limiters as the Cam Degree travel is 60*
4. Timing Chain guide UPGRADE with improved spring.
5. My VVT controller "stand alone" @ $200.00 with software.
6. VVT single bolt AND VVT Oil Pump. (HV)
7. MY HD SINGLE Timing Chain.

I use EAP to "model" PV contact, done for free to LS-1 Tech Members.

The GM Truck VVT calibration IS based on a method to LIMIT Torque required for Drive Train Protection.
My L-92 2007 Escalade had a GREAT improvement in Fuel Millage when I modified the OEM calibration AND MORE Low End Power

Would you like more information ?

Lance

shrapnel

Thanks for the feedback.


I figured I would need valve reliefs. Probably would just have mine flycut.


I didn't realize the 4.8s had a 4L60E. Closest 4.8 harness I can find is in Glen Cove, NY which is about a 4hr drive from me..


I've seen graphs that not only show an increase in torque on the bottom end, but increase in hp on the top end as well. Maybe not on a stock set up, I know both the non-VVT and VVT 5.3s were rated for 315hp. I've read speculation that GM added VVT just to improve emissions and increase mileage.


I am interested in learning more about your Esky, Lance. I am ultimately planning to go FI which I have read affects VVT reliability.


What are you revving to and how much boost are you running? While I see all the pessimists out there saying spring pressure and boost affect VVT reliability, there are guys out there running dual springs and over 14lbs of boost with VVT.

xdanny510x

Try hittin up gpi ... they pretty good on vvt cam

smokeshow

iTrader: (17)

There is a decent power gain from VVT, but looking at the calibration the greatest cam phase angles occur at part throttle, cruise RPM ranges...right where FTP and SFTP emissions cycles spend most of their operating time. Cam retard there helps reduce NOx emissions. However the cam is retarded at higher RPMs which improves top end torque.

You may find pessimism when it comes to VVT due to the calibration effort required for modest gains. In order to get it right you have to populate the response surface coefficients with respect to cam phase angle and phase angle as its effects change with MAP and RPM. Even with the virtual volumetric editor in HP Tuners, the number of iterations it would take to fully calibrate the response surface is time prohibitive. Boost further complicates the matter. It can be done and it would be a cool project, but it will take a long time to do it properly.

pantera_efi

iTrader: (1)

Hi Shapnel, first to "flycut" would be 1/2 the cost of a new +.003" piston, a forged item. (Racetec)

I need more information about your "ESKY" request ?

As for the OTHER VVT "crap" DO NOT BELIEVE those with little experience.

Example : The HP ability of a VVT Motor is in question, NOT TRUE !
You can use the VVT to Advance ONLY, at low RPM then let it Retard at the higher HP requirement of the camshaft. ( Limiters REQUIRED).
The ability to fit a lower timing sprocket with multy-postion "keys" is required.

The calibration I USE for VVT is a simple 2-D strategy, RPM ONLY.

Lance

shrapnel

Looked at GPI cams and they're doing what TSP was doing.. withholding cam specs. Can't build an engine if I don't know what I'm working with. Plus, I have a 5.3. How they say that cam will behave in a L99 is not how it will behave in a smaller engine.

I like TSPs Stage 3 VVT truck cam (216/220) but it is a good cam for a non-VVT engine. One of the things that has me set on a conversion is that I can run a more aggressive cam with less or no low end loss in torque.

BTR offers custom grind VVT cams, you provide the specs you want. I think I will go that route. Thinking along the lines of a 218 or 220 intake duration. The stage 1 L99 cams seem to be slightly more aggressive. I may decide to go more aggressive as I do more research. Who knows.

The Escalade. What is the set up? How much boost? What are you revving to? Problems you ran into switching to VVT and things to look out for? That sort of stuff.

pantera_efi

iTrader: (1)

Hi Shrapnel, Escalade.

I now understand WHY the "ESKY" as LS-1 Tech states THE WORD (Escalade) is misspelled and the SAME with the word Chevelle, misspelled.

My Caddy is used as the Dog Car with the best A/C, rear seats removed, a play pen for my girls. (two goldies)

My only goal with the VVT mod, using HP Tuners for the calibration change, timing changes, and AFR changes was to reduce the fuel consumed.

Lance

jimmyg

I have a 2010 ly6 with a mast vvt cam /springs/ecm/harness. It was N/A for a while , now it has a whipple 2.9 @13-14 lbs boost. Put 12k miles on it since build, I love it. This is in an 83 cutlass

warriorpluto

iTrader: (2)

Are you still selling your vvt software?

Che70velle

iTrader: (6)

You might try his website. He is a former vendor here and doesn’t come around much these days. Website is his name on this site.