stroker motor
11-28-2008, 09:09 PM
#42
5th Gear Member
Join Date: Jan 2006
Location: Puerto Rico
Posts: 3,926
I were not going to post, but I couldn't resist........... I know it is already known that PJB has AFR 165 heads, but here it goes....
If the heads lack in flow, wouldn't it make sense to have them flowing for a longer period of time?
+ duration @.100" and .200"
I'm lost here..... how can lifters collapse with valve closed? 
How can air speed be stalled? Do the intake ports see a 28" of H20 pressure drop across the board? BTW..... what about the bigger volume or cross section area intake port case? Wouldn't having more lift at low RPMS decrease the air velocity even further?...... More area/space + lift, wouldn't it net less air speed?
How does this affect INTAKE?..... it's not just one tennis ball were trying to shoot inside the chamber, but plenty of them. Tennis ***** = A/F..... more A/F in the chamber/cylinder = more A/F to make power?
E-303?
B-303 is 224/224 duration, TFS Stg 1 is 221/225.... wouldn't they be over the 220 duration @.050" lift threshold?
Agree.... it's all in the combo of the whole setup.
An FTI custom cam is specified/made based on the peripherals to be used..... FYI..... check their site...... reducing their work to a "cam tech line" level is more than an insult.... IMHO.
You might want to check the numbers in your example above...... a 700 TQ @6000 RPMS setup = 800 HP.... and 700 TQ from 1000 RPMS all the way to 6000 RPMS? 
OK here lies some of the problem. because I don't know your car I will assume(please correct me if I'm wrong) that you have E7 heads on your car. I've had a lot of stock E7 heads on my flow bench and it's rare to see a set that will flow more that 160 CFM on the intake side. (most of the fall around 150 CFM or less) and here is the big thing. They all reach maximun flow at around .400 inch lift. Pushing the valve to .555 is wasted motion and wasted lift. In your case it's not how far the valve is pushed open but how long it stays open thats going to make the differance. Then assuming your car has the stock induction system with a CIA, bigger T-body and K&N filter it's plenty of air for the stock E7 heads.
Now this isn't to say that the best cam would only have .400 lift but because of ramp angle there is a slight effect on the total duration of the cam. The duration @.50 is a standard so most people will know how that cam will idle because most cam makers have differant methods of measuring duration. This gives the buyer and builder a realistic expectation of how the cam will react.
If I were you this is what I would do. I would find a cam with around .500 lift and 216-220 duration @.50 lift. This will make your car make the best use of mild mods and support even a good port job in the future. It will be easy on the valve train, give you excellant torque right off idle and carry you just past 5000 rpm where the heads will become the limiting factor.
Just a few Cam suggestions I would make would be a FMS B-303or E303, Trick Flow Stage 1 just to name a few of the many. Comp has several that would work well as well as Crane. Edelbrock also has their Performer Hyd Roller that works great with stock E7's (Edelbrock,Trick Flow are ground by Crane).
I can tell you first hand that as the guy who has to put together the right combonation of parts that it's hard not to get a little ahead of yourself. You have to take a realistic approach to getting it right because whats good in one car won't be good in another. Like gear ratios a set of 4.10s don't work best in every car. Low RPM high torque engines like 3:73s better.
Bottom line is your cam is too big and it's like throwing a Hot dog down a hallway. It's not the grinders fault although some of the guys on some of these cam tech lines have no idea what they are doing other than punching your information in a computer program and then rolling off a number. You have to know air flow dynamics to get the ultimate custom grind cam. If you don't know stay conservative and get and off the shelf grind that good for the engine you have. Don't convince yourself you have something you don't. It's the biggest mistake in cam selection.
Staying conservative on your build will result in a car that makes gobs of Torque and when it's all said and done thats what gets the car moving. Big Hp Numbers down at the dyno don't mean squat because HP is just a mathimatical figure based on RPM. I've taken a 700 hp car and blown the doors off 1000 hp+ cars that were dyno queens. The differance was I was making 700 lbs of torque right off idle all the way to my shift point of only 6000 rpm. They were having to wind those dyno queens to 5000 rpm before they started making power. On the street Torque rules.
Last edited by Joel5.0; 11-28-2008 at 09:53 PM.
11-29-2008, 07:47 AM
#43
Join Date: Feb 2008
Location:
Posts: 11
DSS Level 2 Bullet. Order today will have it sitting at your door in a week. I buy my blocks from them and they come looking sterile. I tell them where I want the cyls honed and always dead on the money. I ordered a short block from them and I was impressed. If you knew me you would know that takes a lot. No decent machine shops in my area.
1. Get the wrong grind and it will turn your car into a pig.
2. Everything else revolves around the cam.
3. It determines at what rpm your engine makes peak power. Slide a cam that makes it's power from 4500-6500 in a engine that runs out of breath at 4800 and it's going to be a pig.
4. Even as long as I've neen building engines when I end up picking an off the shelf cam I'll take a step backwards. I have a custom ground cam in my engine. If you were to put it in a stock 5.0 I doubt it would even start much less run well.
5. When getting a cam you have to figure in everything from compression ratio, weight, gear ratio, head flow, exhaust size, induction, cubic inch, and a dozen other things.
2. Everything else revolves around the cam.
3. It determines at what rpm your engine makes peak power. Slide a cam that makes it's power from 4500-6500 in a engine that runs out of breath at 4800 and it's going to be a pig.
4. Even as long as I've neen building engines when I end up picking an off the shelf cam I'll take a step backwards. I have a custom ground cam in my engine. If you were to put it in a stock 5.0 I doubt it would even start much less run well.
5. When getting a cam you have to figure in everything from compression ratio, weight, gear ratio, head flow, exhaust size, induction, cubic inch, and a dozen other things.
2. This is very true. But, why do you say this here and in another thread you say that heads are too big and loose "velocity"? If everything revolves around the cam (and it does BTW) then how can a head be too big? Remember, we do not race flow benches and we do not race dynos.
3. This is misinformation at its best. Use the POS E-Cam. Put it in a 302 with stock heads. Now add a set of aftermarket heads. Is the engine's RPM range going to be the same just because the "cam" is rated for X? Then use the same cam and heads on a 347. The RPM range is still "rated" the same? I have learned in my time of racing and poking around engines that anytime a fool hangs an RPM range to a part, misinformation is abound. You sir are no different.
4. This is because OTS cams are inaccurate. This is because from one lobe to the next they differ in spec. Actually I could go on and on.......This is why I CNC everything I do.
5. You are preeching to the choir. It takes me 2 - 3 HOURS to design lobes and then get it to the camshaft. It is funny to me when you call a phone monkey and within 5 minutes they have the cam for you! Or better yet, "I have a *custom* cam here on the shelf for you!
OK here lies some of the problem. because I don't know your car I will assume(please correct me if I'm wrong) that you have E7 heads on your car. I've had a lot of stock E7 heads on my flow bench and it's rare to see a set that will flow more that 160 CFM on the intake side. (most of the fall around 150 CFM or less) and here is the big thing. They all reach maximun flow at around .400 inch lift. Pushing the valve to .555 is wasted motion and wasted lift. In your case it's not how far the valve is pushed open but how long it stays open thats going to make the differance. Then assuming your car has the stock induction system with a CIA, bigger T-body and K&N filter it's plenty of air for the stock E7 heads.
Now this isn't to say that the best cam would only have .400 lift but because of ramp angle there is a slight effect on the total duration of the cam. The duration @.50 is a standard so most people will know how that cam will idle because most cam makers have differant methods of measuring duration. This gives the buyer and builder a realistic expectation of how the cam will react.
Collapsing lifters? Now this is boarderline retarded. I have PHYSICALLY ran not only in MY junk but in 2 dozen customer's cars a Comp Cams 999-16 spring. 228# on the seat and 608# open. It works and it works like a b!tch. Now if you are using cheap SADI cores and 50.00 OEM Eaton lifters, then maybe you have issues that even YOU don't know. But me and my valuable customers don't use junk.
So the cam has a lower lift at idle than it does at 5000 RPM? When did a 302 start coming with variable valve timing?
If air speed is stalled then the velocity is too great. That means the heads are too small (which is the case 90% of the time). The old time Myths that have been allowed to propagate on message boards is foolish. Most mods don't enough to weed out that bad information from the good. Essentially, if you buy a head because you don't want to loose bottom end, then the head is too small.
A prime example is found iin Big Block Chevys. The LS6 head had a huge rectangular port and flowed massive amounts of air. The LS6 made 450 Hp compared to the LS5 that had small Oval ports and was rated at 365Hp. We learned back in the late 70's when all the LS6 heads were taken that you could take an LS5 oval Port head and clean up the bowls and ports and Those things were capable of 600+ hp with factory castings on a 461 cubic inch engine. Better yet they made way more torque from idle right to 6000 rpm. Then the LS6 heads started to shine. The Oval ports have super fast air speed and thats what fill the cylinders with air/fuel mixtures. Think of it this way. You can shoot a tennis ball farther out of a 3 inch pipe with 100psi than out of a 6 inch pipe with 200 psi.
But the rest is wrong.
Up above you just said that the CAM was the most important thing and that EVERYTHING revolved around the cam. Now you are singing yet another tune.
If the same work is done to a LS-6 head it runs a circle around a LS-5 head. And if they make more TQ, then your CAM was phucked up.
If I were you this is what I would do. I would find a cam with around .500 lift and 216-220 duration @.50 lift. This will make your car make the best use of mild mods and support even a good port job in the future. It will be easy on the valve train, give you excellant torque right off idle and carry you just past 5000 rpm where the heads will become the limiting factor.
And just because he has a .500" lift with 216* at .050", that will automatically be "easy" on the valve train? What is the lobe was 150* at .200"? I could destroy valve springs within 5 minutes.
Just a few Cam suggestions I would make would be a FMS B-303or E303, Trick Flow Stage 1 just to name a few of the many. Comp has several that would work well as well as Crane. Edelbrock also has their Performer Hyd Roller that works great with stock E7's (Edelbrock,Trick Flow are ground by Crane).
You really are a legend in your own mind!
I can tell you first hand that as the guy who has to put together the right combonation of parts that it's hard not to get a little ahead of yourself. You have to take a realistic approach to getting it right because whats good in one car won't be good in another. Like gear ratios a set of 4.10s don't work best in every car. Low RPM high torque engines like 3:73s better.
What is a low RPM engine?
What is a high TQ engine?
Doesn't tire height figure into this?
What about clutch slip or convertor slippage?
Irregardless of the engine, the gear ratio MUST match the RPM range.
Does this classify as "getting ahead of yourself"?
My cam selections are based on your car being stock weight, stock engine with stock heads and the usual bolt-ons. If you will give me detailed information I'll come up with a good selection for you. I've been doing this for a long time and while I left the block machining to the CNC guys years ago. I still do head flow programs for others.
Bottom line is your cam is too big and it's like throwing a Hot dog down a hallway. It's not the grinders fault although some of the guys on some of these cam tech lines have no idea what they are doing other than punching your information in a computer program and then rolling off a number. You have to know air flow dynamics to get the ultimate custom grind cam. If you don't know stay conservative and get and off the shelf grind that good for the engine you have. Don't convince yourself you have something you don't. It's the biggest mistake in cam selection.
His cam is the FARTHEST thing from being "too big".
But, in your opinion, what makes any cam "big" or "small"?
Staying conservative on your build will result in a car that makes gobs of Torque and when it's all said and done thats what gets the car moving. Big Hp Numbers down at the dyno don't mean squat because HP is just a mathimatical figure based on RPM. I've taken a 700 hp car and blown the doors off 1000 hp+ cars that were dyno queens. The differance was I was making 700 lbs of torque right off idle all the way to my shift point of only 6000 rpm. They were having to wind those dyno queens to 5000 rpm before they started making power. On the street Torque rules.
2. 700 TQ off of idle? That is a LIE! 810cid IHRA Pro-Stockers do not do that.
And you sir, excel in this area.
Thread
Thread Starter
Forum
Replies
Last Post
logan409
4.6L (1996-2004 Modular) Mustang
10
09-26-2015 07:43 PM