Mast Motorsports Cam Slugfest (VVT vs LS3)

[SGOS252382]

This is from the GM High Tech Performance Magazine (July 2010)

In the article Mast Motorsports stage 1-3 cams were dyno tested on an L99 and LS3. What I found interesting was that the L99 VVT Mast Motorsports stage 1 and stage 2 cams made more HP and TQ below 5100 rpms than the LS3. Above 5100 rpms they made basically identical power.

The LS3 did make more HP/TQ with the stage 3 cam by 10.4 hp, 8.2 ft. lbs at higher rpms.

I keep hearing about guys doing LS3 conversions, but after reading this article there seems to be some advantages to the VVT cams.

[trudawg660]

how can you put a stage 3 cam on a l99. i thought the AFM cylinder's strings couldn't take it and once u replace them and that deletes AFM. i might be showing my ignorance so don't judge me lol.

[SGOS252382]

Originally Posted by trudawg660

how can you put a stage 3 cam on a l99. i thought the AFM cylinder's strings couldn't take it and once u replace them and that deletes AFM. i might be showing my ignorance so don't judge me lol.

You might know more than I do.

I'm just going off the magazine. They show a stage 3 dyno graph comparing the L99 vs LS3.
Mast Motorsports uses different cams in their packages. The L99 cams have lower lift and have lower compression. Even with a smaller cam, the L99 makes similar HP.

[Sack Rat 2SS]

[QUOTE=
Mast Motorsports uses different cams in their packages. The L99 cams have lower lift and have lower compression. Even with a smaller cam, the L99 makes similar HP.[/QUOTE]

Just read the article and very interesting. Article talks to VVT only and I did not read anything bout AFM or replacing the lifters related to AFM. They were reving the Stage 1, 2, and 3 L99 and LS-3 motors to about 6800 rpm except on the baseline test of the L-99. They replaced valve springs with the replacement cams. Stage 3 comparison used ported heads with the Stage 3 cams to aid heavier breathing needed. Stock heads with Stage 1 and 2 cams. Cams were slightly different between L99 and LS-3 with all three Stages. Also Mast Motorsports limits by half or more the amount the cam phaser can alter cam timing. Stock is 52 degrees of rotation and Mast limits the travel to 32 or 22 degrees depending on cam selected. A mechanical limiter is inserted into the cam phaser to accomplish this. I would assume the ECM has some tuning done to it as well but not sure. Lastly, the article makes the VVT switch appear very attractive for L99 owners. However, we know nothing of the tunes used so we really do not know how to compare the validity of the test done for the magazine. Looks like help is on the way for L-99's.

[mlee]

[silverfox]

L99 with mast stage 1 cam on a procharged 2ss auto. I was running out of fuel at 538rwhp on the dyno and got the fastlane duece pump and went to 573rwhp. I used the trunion upgrade kit from comp because i blew a stock rocker at the strip and i would reccomend the 7.4 pushrods for l99 usage.

[silverfox]

This mast stage 1 cam specs are;
duration@ .50 220/234
lift 573/588
lsa 116 deg

[silverfox]

I need to add that this cam is user friendly on the street but comes on strong at above 3000rpm. You may need to up your idle rpm for this.

[SS-screamer]

Originally Posted by silverfox

I need to add that this cam is user friendly on the street but comes on strong at above 3000rpm. You may need to up your idle rpm for this.

Does it have a nice lope

[2010 SSRS]

cool

[StlRomAniaN]

Originally Posted by SS-screamer

Does it have a nice lope

For some reason I don't like cam lope? I like the sleepers that are quiet then roar with the pedal down. Just my personal taste.

[The 2010 Sin]

then dont do a cam.. just do a kenne bell, "set it and forget it!" lol :-)

[SGOS252382]

Originally Posted by StlRomAniaN

For some reason I don't like cam lope? I like the sleepers that are quiet then roar with the pedal down. Just my personal taste.

That's all in the tune. I had a real strong cam lope on my GTO. I loved it and so did everyone else that heard it. But before I sold my GTO, I had my tuner tune my car so it would idle as close to stock as possible. I was amazed at how he had my car running.
I just assumed it would have a strong cam lope just because the car had a more aggressive cam in it. But that's not always the case. Most cams can be tuned to idle very close to stock like.

[WheelmanSS]

Originally Posted by SGOS252382

That's all in the tune. I had a real strong cam lope on my GTO. I loved it and so did everyone else that heard it. But before I sold my GTO, I had my tuner tune my car so it would idle as close to stock as possible. I was amazed at how he had my car running.
I just assumed it would have a strong cam lope just because the car had a more aggressive cam in it. But that's not always the case. Most cams can be tuned to idle very close to stock like.

That was probably done by raising the value in the TPS and increasing the idle. The "lope" of a cam is a combination of its duration and lobe separation angle... Those are physicaly aspects you just can't remove or "tune out".