Chuck,

Getting a 115 LSA over a 114 won't make much of a difference. Its that 221 deg. of duration thats hurting you. I too am looking for a cam that idles pretty well. I am thinking about a custom Comp 216/216 .525. No valve spring issues and no drivability issues. I personally don't think that the B1 is a 'daily driver' cam. For me anyways. My buddy has one and its too choppy and has idling problems, IMO.

[ November 16, 2001: Message edited by: MyLS1Hauls ]</p>

 

What! The B1 is not a daily driver..? You need to stay with your stock cam.. I have the T1 and it does not idle too much different than my stock 2001 cam. You can hear it more than you can feel it. Thats only because of my headers and dual dual exhaust..

 

[quote]Originally posted by MyLS1Hauls:
<strong>custom Comp 116/116 .525. </strong><hr></blockquote>

Is that a typo? the stock cam is 202/210 .496/.496 116.5 LSA
from what I can find on that other LS1 site.

Maybe I need to stop fighting it, and go with the ol lumpidy lump and stop trying to chase down the perfect old man's cam.. <img src="images/icons/smile.gif" border="0">

Sorry if I am draggin this out, this is an area I never really did any investigation in, and it is very interesting..

Chuck

 

I also am a fan of the "less lift" cams. I don't want to be changing valve springs every year. The cam I want in the future is a 224* / 228* .531" / .539" 112* LSA. It's a Comp Cams grind from More Performance. Can I get a 111* IC ground into the cam so I can install it "straight-up; dot to dot" on a 111* IC?? Or can that only be done during installation (i.e. 112* LSA installed on a 111* IC)??
Any advice on whick springs to use with this cam?

 

A very valid point is brought to light here...and few outside of serious engine builders have embraced it no matter what the application.

Lift is a rider...meaning that we have to have it, but the placement and duration of the valve events make the power.

I have experimented with a ton of cams in hundreds of applications and have never seen a single pattern that would equal a split. The reason is simple....no intake and exhaust port like the exact same valve timing...

Looks like the beginning of a good discussion..glad I got in on it. For the record, different manufacturers have much different takes on lobe design...ramp rates mean a lot when looking at throttle response and maintaining cylinder conditions at RPM. A lazy lobe...like the Lunati....will disappoint, where an aggressive lobe (Reed, UltraDyne, Lazer, and Comp) will completely change a car's personality. <img src="graemlins/burnout.gif" border="0" alt="[Burnout]" />

 

Statistically yep, a split will win out - but the trick is getting the right split. Since there are so many more possible split combinations compared to single it is much harder to get the right one.

Most of the single patters people are using - in the 220-226 range are simply just "hedging" the bets. Sure, they could add in some split, possibly pick up, possibly loose - but the only way to really know is to dyno a bunch of camshafts. That's beyond the budget and time of most consumers here.

Plenty of shops are starting to do this, but since every head isn't identical if we are talking about exact matching then already you have through a variable into the equation.

Don't get me wrong - I agree (if even just from a probabilistic standpoint) that a split should be the most optimized setup - but in reality we as consumers are just trying to hone in on that 95th percentile in the bell curve, not hit the mean head on. The split patterns will generally err on the side of idle quality also, which isn't a bad thing at all!

Again, not disagreeing, just trying to view the situation in a different context.

On the related cam note, have you had any results/experiences with a larger intake duration than exhaust duration - especially on a larger motor? (I know you can't really crutch the intake like that as you could the exhaust, just curious for some real world data).


Chris

 

[quote]Originally posted by ChrisB:
<strong>
On the related cam note, have you had any results/experiences with a larger intake duration than exhaust duration - especially on a larger motor? (I know you can't really crutch the intake like that as you could the exhaust, just curious for some real world data).


Chris</strong><hr></blockquote>

that does bring up a good point. Considering the intake is considered a "restriction" what about a cam with specs of say 226/221 duration @.050 #s?

 

Lunatic:

I believe MTI offered that cam (221/221) with a 116 LSA at one time. Downside is that the powerband my be very top end orientated. Plan on spinning it to 6600 rpm and changing valvesprings every 15k miles if you do spin it high. Some 4.10 gears would be a nice complement to that cam.

 

[quote]I wonder if a vendor has used a test mule and installed several cams in and dyno them with their best heads.. That would take a lot of time, but it would benefit them in the long run.<hr></blockquote>

Yes, MTI has done this. It was how the "T1" was developed 2 years ago. We ordered a ton of different specs and installed/tested them and found out several things in the process. This is why we kept my cam specs "secret" for about 2 months until we were satisfied with drivability and track testing. It was one of the first cars to pull 400+ rwhp with heads/cam and no silly dyno tricks, and the car backed it up at the track. First M6 LS1 in the 11s on radials - full weight. The T1 cam was a winner, and has proven itself many times in this platform.

Things we learned from testing cams:

1. 221-224 intake duration seemed to work best for area under the curve on the LS1.

2. Exhaust durations past 221 showed no additional gains on the LS1. Hardly any difference at all on the dyno curves, but the idle quality got noticeably worse past 228 exhaust duration.

3. The computer set off more misfire codes on split duration cams. Single patterns ran very well with stock fuel/timing programming. MTI does not change the fuel/timing settings on 99% of the cars they work on. But, with the LS1-edit being released will begin doing this.

4. The 0.558" lift on the T1/B1 cams was due to wanting a safe comfort level on piston/valve clearance and the 0.560" coil bind properties of the springs we used back then.

5. MTI is more oriented to producing strong streetable packages. This is the largest base of customers, most of them want emissions passing, proven performance, with little sacrifice in drivability. You hear about their hardcore guys on the net, but that is not their typical customer. The T1/B1 were developed with this in mind, but they just so happen to work for the hardcore guys too.

What is the perfect cam? It is going to depend on your setup and how far you want to go with aggressiveness. Most likely it would be a split pattern, if you could live with the SES lights and rougher idle. I personally don't like that stuff, and I'm happy with my stock tuning and better drivability, something I'll never sacrifice as long as I own a street car. If my car were to sit on a trailer full time, it would have one big, badass solid roller split duration cam and open headers. But, back to reality <img src="images/icons/smile.gif" border="0">

Someone asked the difference between B1 and T1 on the dynojet. I have a good graph for you to look at. This dyno shows three different cars with CNC heads, MAC headers with catalytics, Borla, pulley, and airbox. All identical packages, no free mods. All were bone stock when brought in and had the "Stage 1" complete package done to them. Two cars have a B1 cam, one has the T1. Only difference. Notice the lower rpm torque on the T1 car is slightly better, but the peak rwhp is about the same. At the track, all three of these cars would run identically since we only run in that high rpm, but for daily driving that lower torque increase will feel more "fun".



Pretty consistent huh?

Tony

[ November 15, 2001: Message edited by: Nine Ball ]</p>

 

[quote]Originally posted by LEO:
<strong>

That also has alot to do with how well he ran - the entire pkg. is what you have to look at.</strong><hr></blockquote>

you got that right its all about combo some people get lucky others have a combo that just works time and time again. That is why its easiest to go with an MTI Stage 2 package or the like and your results should be very close to others out there

some like to be pioneers and that just costs money and lots of times less than desireable results

 

The times Chris' car put down that night were an exception, not the rule. His car had recently been rearended and he had to remove the entire catback because it got bent up, so his car had NO exhaust at all, open headers (light!) and he also purposely gutted his entire car to come make the passes. The weather was also exceptional that night, DA was probably well into the -1000' range. Just the right track (HRP) at the right time, with a lightweight car.

Similar to how Raughammer ran a string of 10.8s on motor with a similar setup and lightweight.

G2, those "dyno tricks" are frowned upon down here. Only the ricers do that stuff. Those guys spray keyboard cleaner (compressed air, comes out freezing cold from depressurization) into their air filters during dyno runs. ****.

Tony

 

Comp cams normally come with 3 degrees advance ground into the cam. What is the optimum advance or retard or straight up to install the cam in various applications?

 

Tony,

Great post with the info on the T1/B1 cams. Overall, this entire topic has to rank in the top five that I have ever read.

For the question - when MTI did the testing on the intake duration, and found that the 221-224 intake duration was best, I assume that was on a stock cubed motor. Knowing that this question is of course dependent upon heads, valve sizes, exhaust, etc., what has been their experience (or anyone elses) with larger intake/exhaust duration on larger cubed motors (e.g., the 383 or 422)? My assumption is that you can get away with a little more duration (and still have drivability) due to the larger stroke/displacement, but I was wondering how much this has been tested. Anyone else know??

BTW, I have about three weeks left to decide what to put in the 422 I am getting. I don't want to have to fool with this too much since I am already spending a crazy amount of money on all of this. I am looking at a single pattern 112 LSA with undecided duration somewhere between 221 and 231, but may change my mind as I learn more.

 

I have to agree with Tony.. I have raced many split duration setups. I am not impressed.. I do not even have heads yet and I beat them. The research behind the T1 cam is awesome and it works for most drivers..

 

[quote]Originally posted by vmoore:
<strong>So you have noticed this too Josh.. I asked that in my first question. Did Chris Johnson get lucky or is there some logic behind his setup..?</strong><hr></blockquote>

I think Chris picked a good cam, has a good set of heads on his car, ANDdid you ever look at how much his car weighed or what kind of gear he is running? That also has alot to do with how well he ran - the entire pkg. is what you have to look at.

 

I would have to disagree that exhaust duration numbers bigger than 221 don't pick up numbers....I can tell you that all of my exhaust lobes are over 221 and will make more across the board than a smaller duration lobe...

The key to the "driveability" issues rest with tuning once the cam lobe is maximized. Perhaps that is why the single patterns are favored..because too many people rely on hand held programmers or the wrong person to flash their PCM. You really can't expect to drop a cam and head package on a car with stock programming and set the world on fire either. Adaptive strategy MAF systems are good...but not that good.

I still see the split as the way to go and all of the fears about those are simply products of a poorly tuned combination.

 

Many here have stated that high lifts can be troublesome due to the cams fast ramp rates. I think Terry pointed out this very well.

My opinion; For an A4 daily driver, my choice would be a 218/218 .527 .527 114 LSA
As Terry pointed out, single pattern duration cams seem to have better idle characteristics. A 114 LSA will also idle better than say a 112 LSA.

As far as lift, you need to remember; Your stock LS1 cam had about .498 lift. A .527 lift that I recommended above is substantially greater than stock, but would pose many less long term problems than the cams in the .550-.560 lift area.

Just my opinion,
Ron

 

So what your saying is a 221/221 with a .560 lift wont dyno much more than a 221/221 cam with .525 lift, and the cam w/ the lower lift will obviously be less stressful on the valvetrain? Are there any cams out there that have around 218-221 duration with lifts in the .530- .540 range?

 

What about ramp rates and duration at .006 lift? I think that this is failry important and hasn't been discussed yet.

 

Well lets throw some bones to the turbo guys. my turbotech setup has a very restrictive exhaust setup in my opinion. Anything I can do with a cam to help it? Noone seems to try a cam with a turbo so I may have to be the lab rat