mast motorsports l92 cam

[tinroof]

Anyone here have an L99 or L92 that they have done a mast motorsports cam swap on? I have an L92 in a my 69 C10, and I'm thinking of doing it. But I'm worried about all the downsides that come with the bigger cam. But, the way I understand it, the VVT advances the timing so you don't get the downsides. If I'm going to lose any bottom end torque, drivability, reliability, etc, then I'd just assume leave it alone. Anyone done it, have any experience swapping VVT cams? Any input....thanks

[BR3W CITY]

Thats not exactly how VVT works. If your interested in a cam, I'd suggest taking a look through the builds section, and the "What ya got" threads. We've had many members who've done these swaps with l92 (GenIV) motors, and all types of cams.

Whether or not you "lose" torque will depend on the choice and spec's of the cam. A huge lift cam will always prefer higher rpm, and make peak HP. That doesn't mean you'll have a gutless wonder around town. Just the same, you could spec a super torque-y cam and have guys complain that they are "losing" power up top. Your not losing anything, as your dyno #'s in both categories will still be higher than stock.

Driveability has more to do with your converter and tune than it does the cam itself. Even a high lift +super low LSA car can be made to run smoothly around town. The reason folks complain that wild/big cam cars are hard to drive is the cam surge and part throttle response. As long as the combination of parts isn't completely wacky, all the driveability stuff should be handled by the tuner.

IMO I'd suggest looking at what our other members have done already. There is a huuuuge amount of knowledge floating around between us, and pretty much every combo mild-wild has already been tried at some point.

Define your goals, what you want to do in the longrun, and a budget.

[tinroof]

Then how does VVT work exactly? The way Damon at Mast Motorsports explained it to me, is that it advances the timing as much as 7 degrees, and retards it 6 (depending on RPM). This is all new stuff for me, and I'm trying to learn as much as I can. I want your wisdom

[PGSigns]

The VVT actually advances or retards the cam Timing. Can ad power to the bottom end and the top end. Here is a good article on just what you are thinking of doing. As with any LS mod the tune up is everything.
Jimmy
http://www.hotrod.com/how-to/engine/...formance-test/

[BR3W CITY]

Originally Posted by tinroof

Then how does VVT work exactly? The way Damon at Mast Motorsports explained it to me, is that it advances the timing as much as 7 degrees, and retards it 6 (depending on RPM). This is all new stuff for me, and I'm trying to learn as much as I can. I want your wisdom

Its not that the mechanical explanation of VVT thats incorrect, its the "big cam without the downside" part. VVT doesn't change overlap, lift, duration, or LSA of the cam. It may seem like I'm nitpicking the statement, but we literally just ran into this with a customer. That person made a similar assumption, bought a cam that was way too much for his current setup, and was unhappy that (despite solid gains and a lengthy driveability test/tune) it didn't "feel the way it did when it was stock".

My first post still applies; big cams can be made to be very streetable, but you will always have a side effect. Whether it be a higher idle, more "chop" or vibration etc. VVT will not change that, and it won't help at all if the cam is way off the deep end on a car that doesn't have the supporting mods.

[tinroof]

First of all, let me say thanks for the input. And thanks for the link, but I've read it already. I searched some of the threads for people with LY6 and L92 engines, and sent several private messages, only one has responded so far. I know how VVT works. I've read up on it A LOT. And I've talked to Damon at Mast Motorsports. He told me that it would have a more choppy idle, and it will affect the engine's vacuum. Which could affect brakes. But as far as low rpm torque, he said that will actually get better, and so will the top end HP. And it's all because of the VVT. While I don't believe he would lie, we also have to remember that he is trying to sell a product, and will talk it up like it's the best thing since sliced bread. I've had experience building old Gen I engines with big cams, and know the affects of it. But this is my first LS engine, and first VVT engine. From what I know and have heard so far, I think I would be happy with it. I was just hoping to talk to some people who have done bigger cams on them, get their opinion before I do it myself, and find out it was a mistake. Thanks

[BR3W CITY]

I'm not trying to talk you out of it, just making sure you aren't wearing rose colored shades. Damon is a good guy, and he's not lying, just portraying things in a positive (read: business) manner.

FWIW, don't get hung up on having a big cam because its big. There are MANY cases in which less cam makes more power.

[tinroof]

Let ask a question then (as stupid as it may sound), is it possible to have a big cammed engine that still does good pulling a load? Because with my experience building old Gen I engines: I had a 327 in my truck previously. I dropped down from a .488 to a .458 cam in it. HUGE difference in how it pulled my boat. But that was an old engine. I know these LS engines are different though

I've been thinking about getting HP tuner and playing with it some, but from what I understand, not just any Joe can pick up HP tuner and start tuning. You have to know what you're doing, right?

What I want (but don't NEED of course), is as much power as I can get, on both top end and low end without sacrificing too much of one or the other. While still having something that is a good daily driver, still pulls a load good, and without sacrificing too much fuel economy.

When I found out that you could get as much as 125 more hp with just a cam and valve spring swap, and a computer tune of course, I started druling

[tinroof]

Oh, and you're going to have to explain what you mean when you say "it's all in the tune" I know you can tune one and get more performance, but it's always been under the impression that about 30 more hp is all you can get out of one with a tune. I didn't know you could get that much more

[BR3W CITY]

Originally Posted by tinroof

Let ask a question then (as stupid as it may sound), is it possible to have a big cammed engine that still does good pulling a load?

Yes its possible, but its easier to do so on a larger cube engine. You can have a good cam that still gains power and can pull a boat, however in general I wouldn't consider them "big". VVT cams aren't really being done in .650+ lifts, I think most are under .570


I've been thinking about getting HP tuner and playing with it some, but from what I understand, not just any Joe can pick up HP tuner and start tuning. You have to know what you're doing, right?

When you do the swap, someone will need to use a program like HP Tuners to delete your emission controls and VATS. Technically, you CAN do that yourself, but actually messing with VE, PE, spark timing etc is where the "real" tuning starts and where it gets harder. I'd say anyone can get it to work, but not anyone can get it to be good.

What I want (but don't NEED of course), is as much power as I can get, on both top end and low end without sacrificing too much of one or the other. While still having something that is a good daily driver, still pulls a load good, and without sacrificing too much fuel economy.

That can all be done with a reasonably tame cam if you'll be sticking to a mostly stock motor. As you mention just below, its impressive what you can do with a cam swap and some tuning.

When I found out that you could get as much as 125 more hp with just a cam and valve spring swap, and a computer tune of course, I started druling

I scribbled some suggestions in the quote.

[BR3W CITY]

Originally Posted by tinroof

Oh, and you're going to have to explain what you mean when you say "it's all in the tune" I know you can tune one and get more performance, but it's always been under the impression that about 30 more hp is all you can get out of one with a tune. I didn't know you could get that much more

Your potential gain is more like a mathematical function than a set rule. Stock and mildly modded LS motors can see anywhere from 30-60hp from proper tuning and emissions removal. A highly modified turbo LS motor might see a potential 100hp or more from tuning. All out race motors can fluctuate 100's of horsepower based on the fueling and spark in the tune. Think of of it like a sliding scale.

[tinroof]

Yeah, I guess we should have gotten on the same page from the beginning on what we consider a "big cam" The Mast L92 HO cam is around a .587 I think. To me, that is a really big cam for a street vehicle. But, I'm new to this. Your customer that wasn't happy because "it didn't feel stock anymore" How big was that cam?

[BR3W CITY]

He put an MS3 in a stock CTSV (with existing mechanical problems he refused to fix), which is a 237/242 .603/.609


My cam is a 235/240 .648/.609 I would call it big.

[bpatrol]

on vvt cams th "lift" changes. I have a ly6 6.0 with a texas seed vvt-2 in it and th lift can go to.620
my exact cam
http://texas-speed.com/p-773-texas-s...-camshaft.aspx

[tinroof]

Oh, and just to clarify, I wasn't trying to knock Damon. He's a cool guy, I like him. He's been real cool about answering all my questions. I was just trying to think like a businessman