Vizard on 106* LSA vs 112* LSA in a BBC

[dfree383]

I am allready sick and tired of hearing all this, but I will just say this one more time, if you are wanting the most performance for your engine, you will be better off with tighter centers than wider centers- I am not talking about street drivers, but street racers or drag racers. MANY people get mixed up between street and race- they are NOT the same

JOE SHERMAN RACING ENGINES

I'd have to agree with this........

[3V Performance]

Now I'm confused.

(if you are wanting the most performance for your engine, you will be better off with tighter centers than wider centers- I am not talking about street drivers, but street racers or drag racers. )

(Here is the way I see it-- The better the head, the more it will like wide centers. the WEAKER the head, the more it will want tighter centers-- It works this way on every engine I have ever seen )

Would the drag engine have the better heads and wider centers or better heads and tight centers for better performance?

[CNC BLOCKS]

Now I'm confused.

(if you are wanting the most performance for your engine, you will be better off with tighter centers than wider centers- I am not talking about street drivers, but street racers or drag racers. )

(Here is the way I see it-- The better the head, the more it will like wide centers. the WEAKER the head, the more it will want tighter centers-- It works this way on every engine I have ever seen )

Would the drag engine have the better heads and wider centers or better heads and tight centers for better performance?

Those quotes from Joe really have me confused!!!

[Stan Weiss]

Does anyone have a list of cam companies offering BBC cams on such tight LSAs? Or of BBC cams made with such LSAs?
I know at UltraDyne, from 1980 on, two of our most popular BBC cams, the BB288/296F7 and the BB286/300R7, were extremely popular ground on 107 LSAs.
However, they were almost unstreetable, at least for the average guy.....

UDHarold

From the same article.

So that you are not left wondering what you should use, here are three grinds that I can personally vouch for using. Lunati's big-area-generating Voodoo street rollers: BBDV281-06SRH, BBDV286-06SRH, and BBDV292-06SRH. These are single-pattern cams using Lunati's VSR32, VRS34 and VSR36 profiles respectively. These cams are optimal for a 489 to 511 inch big-block with typical aftermarket heads and a compression ratio between 10:1 and 11.5:1


UDHarold did you design these cams?

[bigjoe1]

I do not want to get anybody confused-- Lets go this way- up to around 1.50 HP per cubic inch is not very serious, I call street racer ( what ever ) as you get closer to 2.00 HP per cube, I start calling this a serious race piece--The more HP per cubic inch, the engine will want or like the spread centers( It will also have very high compression, and so forth )Maybe I should put it this way, on pump gas, I go for the tighter centers all the way- Even when I run a 114 center cam, it does not have as much mid range as the closer centers, but it will have more top end horsepower- I hope this helps explain my thinking

JOE SHERMAN RACING ENGINES

[Troy Patterson]

That's my experience also Joe. I have found however, with carb work I can keep the top end horsepower of the wide angled and make the torque of the narrower lobe center angle - and widen the usable rpm range further still.

Troy Patterson TMPCarbs.net TMP Carbs

[srv601]

I think maybe there selling magazines,i went and bought one... really the best part is the (notes from the editor witch appears last . '' please do not be insulted.rather,it is the desire of the PHR editorial staff that you take away the overreaching technical concepts.''

also here my fav '' street rollers from comp or lunati will go more than 50.000 miles between adjustments.''

this is just a pump gas bbc story witch is the same rehash written by this and other mags 20 times a year-one month it's port your oval port heads to run pro stock numbers to this must have alum aftermarket heads and latest cam mfg hype to sell cams.smoke and mirrors and thumpenvoodo

[UDHarold]

Stan,

I designed ALL the VooDoo cams, hydraulic, solid, hydraulic roller, and solid roller. I just did 5 more for the LS1, sent in Sunday.
I was not asked to take part in any testing done by Dave Vizard, and I do not yet have a copy of the article.
However, if those are single-pattern cams on a 106 LSA, they would have tremendous mid-range power, and probably fall flat at a little over 6500.
If that was what he was looking for, those cams would deliver it.
I run 107, 108, and 109 when I want good mid-range, and some top-end too.

UDHarold

[Orr89rocz]

That's my experience also Joe. I have found however, with carb work I can keep the top end horsepower of the wide angled and make the torque of the narrower lobe center angle - and widen the usable rpm range further still.

Troy Patterson TMPCarbs.net TMP Carbs

This brings up a point. What about EFI? If carb work changes how cams can react, i'm assuming thats because your getting better mixture distribution with carb work and valve event timing will depend on that fuel delivery?

So how does precise fuel injection react to cam lobe centers? ALOT of the sbc LT1 motors are using tight centers with good success. But there are some wide center guys making good power too. LSx guys seem to run much wider centers compared to sbc/LT1 so I assume thats because of the valve angle of the heads and improved flow characteristics.

Most guys use wide centers to eliminate overlap at idle to keep narrow band o2 sensor happy. If you run open loop like i have, then no worries about o2 sensor at idle and you tighten that LSA up. So any thoughts on EFI or even valve angle in heads that may effect lobe centers

[UDHarold]

Stan,

I designed those lobes as part of the original VooDoo street rollers. All information was left on Lunati's computer, which was consequently taken to Holley at Bowling Green. After that, no one knows what happened to it.

VSR-32 268 at .020, 237 at .050, .3775" lobe lift
VSR-34 274 at .020, 243 at .050, .3850" lobe lift
VSR-36 280 at .020, 249 at .050, .3903" lobe lift

.200 numbers aren't on my new computer, but I later designed 3 similar cams, all with .393" lobe lift. Their .200 durations are:
158
164
169

They have been very successful as daily drivers, mostly on 112 LSAs.....

UDHarold

[Stan Weiss]

Harold,
Were you at General Kinetics at the same time as Gregg Koechlien?
Stan

[UDHarold]

Stan,

I was Gregg's replacement........
I met him there the year before(1973), and several times when he worked in NJ.

UDHarold

[540 RAT]

I do not want to get anybody confused-- Lets go this way- up to around 1.50 HP per cubic inch is not very serious, I call street racer ( what ever ) as you get closer to 2.00 HP per cube, I start calling this a serious race piece--The more HP per cubic inch, the engine will want or like the spread centers( It will also have very high compression, and so forth )Maybe I should put it this way, on pump gas, I go for the tighter centers all the way- Even when I run a 114 center cam, it does not have as much mid range as the closer centers, but it will have more top end horsepower- I hope this helps explain my thinking

JOE SHERMAN RACING ENGINES

Thanks Joe, good info there. That's the kind of real world experience that stands up against mere speculation.

So, if we consider Vizard's pump gas, 700 hp, 505ci, 106* LSA, BBC, from the original posting here, that motor comes in at about 1.4 HP per cubic inch. Now using Big Joe's guideline above, then for comparison purposes, a reasonable compression pump gas 540 making 800hp, is right at 1.5 hp per cubic inch, and he calls that a street racer. While a high compression 1,080 hp 540 would be at 2.0 hp per cubic inch, and he would call that a serious race piece. So, with that being the case, then Vizard's motor also falls squarely into the pump gas street racer category, and his 106* LSA cam was absolutely the correct choice for that motor. And it clearly made better numbers using the narrow LSA cam than it did with the wider 112* LSA, confirming exactly what Joe said about narrow LSA's being the best choice for the highest performance in a pump gas motor. Big Joe and Vizard "BOTH SAY THE SAME THING." Nuff said………...

[Stan Weiss]

Stan,

I was Gregg's replacement........
I met him there the year before(1973), and several times when he worked in NJ.

UDHarold

Harold,
During that time period my cousin lived in Northern Jersey and know Gregg so 4 or 5 times a year I would get to see him and we would seat around and bench race. That was a long time ago.
Stan

[3V Performance]

Thanks Joe, good info there. That's the kind of real world experience that stands up against mere speculation.

So, if we consider Vizard's pump gas, 700 hp, 505ci, 106* LSA, BBC, from the original posting here, that motor comes in at about 1.4 HP per cubic inch. Now using Big Joe's guideline above, then for comparison purposes, a reasonable compression pump gas 540 making 800hp, is right at 1.5 hp per cubic inch, and he calls that a street racer. While a high compression 1,080 hp 540 would be at 2.0 hp per cubic inch, and he would call that a serious race piece. So, with that being the case, then Vizard's motor also falls squarely into the pump gas street racer category, and his 106* LSA cam was absolutely the correct choice for that motor. And it clearly made better numbers using the narrow LSA cam than it did with the wider 112* LSA, confirming exactly what Joe said about narrow LSA's being the best choice for the highest performance in a pump gas motor. Big Joe and Vizard "BOTH SAY THE SAME THING." Nuff said………...

But it's not what Joe said. This is what makes his quote confusing.

1) if you are wanting the most performance for your engine, you will be better off with tighter centers than wider centers- I am not talking about street drivers, but street racers or drag racers.

To me this sounds like a 1.5 or higher HP per cubic inch engine will always want tighter centers to make most power.

2) Here is the way I see it-- The better the head, the more it will like wide centers. the WEAKER the head, the more it will want tighter centers-- It works this way on every engine I have ever seen

Now to me street racers or drag racers would have STRONGER heads needing wider centers BUT in above post he is saying tighter??

3)Lets go this way- up to around 1.50 HP per cubic inch is not very serious, I call street racer ( what ever ) as you get closer to 2.00 HP per cube, I start calling this a serious race piece--The more HP per cubic inch, the engine will want or like the spread centers( It will also have very high compression, and so forth )Maybe I should put it this way, on pump gas, I go for the tighter centers all the way- Even when I run a 114 center cam, it does not have as much mid range as the closer centers

Now here were saying 2hp per cubic inch WIDE centers but in the same quote if it's pump gas TIGHT centers. Yet my 360ci small block makes 850+ hp (2.4hp per cubic inch) and runs tight center (109) on race gas ( 12to1 comp) Put this on 114 and get run over.

I think this is a perfect example as to why 1 rule does not alway's apply. There are to many variables to make a blanket statement or quote. JMO