My heads have been flow tested need help with a cam grind

F

Faytmorgan

Member
I was sent here from Hyrbridz.org for help.

195cc intake runner, 64cc combustion chamber, aluminum, 2.02, and 1.60 valves
Superflow sf 600 flow com
air speed: 380-400FT, 375-410SC

Intake;
(.1)66
(.2)141
(.3)200
(.4)242
(.5)270
(.6)265
(.7)268

Exhaust;
(.1)55
(.2)107
(.3)139
(.4)167
(.5)192
(.6)209

2500lb car 245/50r16 street tires rated at 320aa by firestone (I don't really need tq the car is very light and I am limited on tire)

1978 280z long nose r200 diff. with stub axles

1987 700r4 trans
3.545 rear gear ratio
10.25:1 compression
chev 327 40 over now may end up 60 over soon
1.6:1 rocker ratio

Looking for a solid flat tappet.

I'm looking to have a very WIDE rpm range, as much as possible. Comp claims the old duntov 30-30 is between 2300-6900. I'm talking that kind of wide. The issue with that cam is that the one they sell it for a 350, in a 327 that would bump my rpm past what I want it to be. The 30-30 does suck (compared to modern cam profiles), I am just pointing out that a wide powerband in a solid flat tappet can be done. Also when I was saying the difference between a 350 and a 327. The small crank throw will up the rpm a bit. Instead of being at 2300 it would be like 2500-2600, and instead of being 6900 it would be like 7200-7300. That is too peaky for me. 2300 to 6900 would be perfect if it was rated for the 327. When comp rates those numbers they are all done with a 350 base. Not a 3.25 but a 3.48 crank.

I'm looking for a 6700-7000 peak rpm, with it coming in as low as I can get it at.

One thing I have heard and read a lot of debate about is the fact that the 327 doesn't sit at top dead center for very long so a wide lsa (about a 112-114) would be beneficial. Also it would kill the tq down low. The other end of this opinion is that one could do a 110 lsa and advance it quite a bit. I don't honestly know what would be best. Some help/thoughts/advice would be great.

The car is intended for the road course at BIR in MN. Both the outer longer track and shorter center track.
http://www.brainerdraceway.com/

It looks like 1st gear is just to get going and 2nd gear should be about 33 mph at 2500 rpm and will be 80mph at 6000rpm. 3rd will go from 55mph @ 2500rpm to 130 @ 6000rpm or 140 @ 6500 rpm so 3rd should be a great gear for most of the high speed sections. 2nd should be enough for any tight stuff. Overdrive is 200mph + so that's good for a bit of extra pull down a straight if I'm able to go faster than 140mph before braking for the turn.

Looking at the Brainerd track it looks like a lot of high speed corners and long straightaways without too many tight corners. I have wide gearing so this should suit the track well but it means I need a wide powerband as well.

Help and advise or a point in the right direction would be great.
 
Re: My heads have been flow tested need help with a cam grin

sure would help to know, your deck height, quench, head gasket thickness, piston dome or dish CC (static compression, may be listed as 10.25 but knowing the true clearances helps, and unless you have a dome piston on that 327, youll have a hard time getting a true 10.25 cpr ) and true converter stall speed, plus your valve spring load rates,assembled height, spring bind, and header dimensions, I assume youll run a very low restriction exhaust.
yeah! could just suggest a cam, but knowing more would sure help here!


USE THE CALCULATORS to match port size to intended rpm levels... but keep in mind valve lift and port flow limitations[/color]
http://www.wallaceracing.com/runnertorquecalc.php
http://www.wallaceracing.com/ca-calc.php
http://www.wallaceracing.com/area-under-curve.php
http://www.wallaceracing.com/chokepoint.php
http://www.wallaceracing.com/header_length.php
 
Re: My heads have been flow tested need help with a cam grin

We are doing springs after we get the cam (travis knowlton at knowlton thunderhead and racing engines).
http://www.ktrestore.com/

The header is a shorty bbk made for a ford modified to work for a chevy. I wanted equal length. I am rather particular about that. This is the plan at least, I can't find a long tube that is equal length (100% for sure), and will for sure fit in the z.
http://www.summitracing.com/parts/BBK-15290/

"deck height, quench, head gasket thickness, piston dome or dish CC, true converter stall speed, plus your valve spring load rates,assembled height, spring bind" I don't know any of this because we are starting with the heads first. I come from building Honda's myself. In my opinion the heads are where its at if you catch me.

As for the trans, I have a core that is not built yet. Engine first than the trans, hence why I don't have a converter yet.

Thanks for the reply grumpy. Do you have any thoughts, comments, suggestions? Again I just have the heads done, I do have valves. I was thinking of beehive springs for weight so I can rev the motor up. I like rpm and hp. One only (in physics) need only as much tq as it takes to get the car moving the rest is hp. Otherwise I will be just spinning tires. Which to people in the 16yo range I am sure is a blast, but I want to the ground performance.
 
Re: My heads have been flow tested need help with a cam grin

your intake manifold and carb will also have an effect on the engines power curve.
lets go at this step by step,
basics how much horsepower do you expect to make or need and why would you run a 327 when a 377,383,406 built correctly will leave any 327 with a 3.50:1 rear gear looking at tail lights in that car? you may not think you need torque but you do! you need as much as you can get over as wide a rpm band as you can manage, and don,t thing rpms can make up for displacement and torque, especially with a rear gear ratio that will require MASSIVE amounts of torque to push the car to higher speeds.
BTW the springs get selected to match the intended rpm band and cam, you can,t just install springs and then throw a cam in and expect the two to work well together.
don,t let people give you bad info, a 377-383-406 car reve just as fast and yet produce much more power, you might be restricted to 6500rpm vs 7500 rpm but in either case your looking at about 1.25 hp PER CUBIC INCH OF DISPLACEMENT with those heads in a combo designed to operate well at lower rpms and burn pump gas, if your willing to install a cam capable of spinning 7000rpm your going to make a good deal more power but compromise low rpm drive-ability

ball park with those heads, and a cam designed for both brisk acceleration and good driveability
327 x 1.25=410 hp
377 x 1.25= 470hp
406 x 1.25=508hp

these may help
viewtopic.php?f=69&t=519

viewtopic.php?f=69&t=2645

viewtopic.php?f=69&t=1487

viewtopic.php?f=69&t=1550
 
Re: My heads have been flow tested need help with a cam grin

I can only run a 8.5inch street tire in my class. That's why I am limiting the tq DOWN LOW, I will need it at the top and in the midrange. We are going to try different carbs and tunes on the dyno. The intake will be a single plane, I am not sure which one yet. I like the team g myself. Its not that the bigger engines can't rev. a 500ci caddy can rev to 8k with the proper setup. I have seen it in person. The issue is too much tq will fling this car sideways. my l28 can spin the tires as is now.

Regardless, of the tq argument. I have a 2 bolt small journal 327 40 over right now. Forged crank. I have rods that I am not sure I am going to use. I don't have good pistons at the moment. I am waiting on the cam selection.

The cam will determine the rest of my valve train choices to make sure they all work out. I do want to go with a 1.6 ratio.

Also I was told that its 1.8 hp per cfm on the low end and 2.2 hp per cfm on the high end. Everyone has their opinion on hp out put. I don't care about guesstimations, I like dyno proven.

I expect to make as much hp as the engine makes ;)
 
Re: My heads have been flow tested need help with a cam grin

heres crower 619.661.6477
and cranes 866-388-5120

phone numbers, obviously youll want to verify, don,t be surprised if they suggest a milder cam unless you tell them its used 90% for racing the car, between the large port single plane intake and fairly radical cams for that displacement and compression ratio,too much low rpm torque will not be a huge issue

make sure you have a full 10.25:1 cpr minimum Id suggest a 3200rpm stall converter
and a cam similar to these, either will come close to maximizing those ports with a 1.6:1 ratio rocker
BTW
http://www.summitracing.com/parts/HLY-300-110/
hly-300-110.jpg

this intakes great between about 3700rpm and about 6800rpm, but its pretty much wasted with out a decent cam with at least 240 dur at .050 lift and killer heads,that flow at least 250cfm at .500 lift or with a supercharger with killer heads that flow at least 250cfm at .500 lift and a decent cam with at least 240 dur. at .050 lift and of course a low restriction exhaust and headers

crower00322.jpg

crane114681.jpg


viewtopic.php?f=56&t=7017
 
Re: My heads have been flow tested need help with a cam grin

What are your thoughts on the LSA? I talked about the 327 not being at tdc for long needing a wider lsa vs say 110 with a lot of advance etc.
 
Re: My heads have been flow tested need help with a cam grin

capital letters are not yelling, IM JUST POINTING OUT THE DIFFERENT CONCEPTS HERE
LSAChart01.jpg

the ideal lsa for a 327 is near 109-110 lsa

your basically trying to have the best of both concepts and not be bothered with the fact that a 327 strong point is the ability to spin 7500rpm fairly easy, where a solid lifter flat tappet cam with a good deal more duration and a higher compression ratio are normally used, but then you throw a 3.5:1 rear gear and a need to run lower rpms, with an auto transmission ,making a much lower duration cam a compromise.
you can,t have it both ways,without a turbo .
you can either gear the car with a 4.11:1 rear gear and put in a 4500stall converter and 12;1 CPR AND SPEND ALL YOUR TIME IN THE 4500RPM-7500RPM BAND MAKING DECENT POWER AND REQUIRING RACE OCTANE FUEL
or
YOU CAN COMPROMISE , USE THE 3.5:1 REAR GEAR, 3200 STALL AND MILDER CAM DURATION AND WIDER 112 LSA AND FAIRLY LOW 10:25:1 COMPRESSION AND GIVE UP SOME HIGH RPM POWER BAND AS A RESULT

700r4speed1.jpg


heres what DD200 predicts for that crower cam on a 10.25:1 327, with open headers, 1.6:1 roller rockers(you best run a rocker stud girdle)personally I think its predicted power level is optimistic for a 327, and more likely with a 383 built in a similar manor but at lower average rpm levels
327dynocrower.jpg
 
Re: My heads have been flow tested need help with a cam grin

The 10.25:1 is because we will be running on pump gas, i'm using a 25.56 inch tire btw not 24
 
Re: My heads have been flow tested need help with a cam grin

I can't replicate what you did on dd. How do you set the rocker ratio? I put the same numbers you did aside that I can't find the icl you put the cam at. I am only getting like 471 at 6500 with a 112lsa 110icl, 248/254, and .542/.562.

What am I doing wrong here?
 
Re: My heads have been flow tested need help with a cam grin

Faytmorgan said:
I can't replicate what you did on dd. How do you set the rocker ratio?

take the cams listed lift ,divide by the stock ratio (15) then multiply by the new (16) to get the lift

I put the same numbers you did aside that I can't find the icl you put the cam at. I am only getting like 471 at 6500 with a 112lsa 110icl, 248/254, and .542/.562.

What am I doing wrong here?
Click to expand...

did you swap from SEAT-TO-SEAT ...TO .050 lift timing in the program?before entering specs, and enter class as circle track profile?
 
Re: My heads have been flow tested need help with a cam grin

I had it set up as a high performance street profile. What the heck is the difference if a cam's lobe x why should it matter?
 
Re: My heads have been flow tested need help with a cam grin

I don,t know why several of the choices mater , and data parameters change ,but if you select the closest choice description too the actual cam design being used you get more consistent results in DD2000
 
Re: My heads have been flow tested need help with a cam grin

You have the combustion space at 72.35 I have mine at 73.81cc I don't get how that works seeing I put in 10.25 combustion.

I am still only getting 464 at 6500 and 432 at 5000 (which is worse than before)

I did what you said to do with the cam
using 112lsa, 108icl, 248/258, 542/562

when playing with the program myself the best results I get are when i use
116lsa, 116 icl, 254/269, 600/600
 
Re: My heads have been flow tested need help with a cam grin

Faytmorgan said:
You have the combustion space at 72.35 I have mine at 73.81cc I don't get how that works seeing I put in 10.25 combustion.

I am still only getting 464 at 6500 and 432 at 5000 (which is worse than before)

I did what you said to do with the cam
using 112lsa, 108icl, 248/258, 542/562

when playing with the program myself the best results I get are when i use
116lsa, 116 icl, 254/269, 600/600
Click to expand...


if your getting the best results with a 116 LSA and a 254/269, 600/600 its a good indication that the cam durations too large for the application, when you have the correct duration youll find the best power some where close to the 107-111 LSA range and have a DYNAMIC compression ratio close to 8:1, my experience tends to make me think a combo like your working ion will prefer a tighter 107-108 LSA.
BTW DD2000 is fun to play with but its hardly exact.

here if you want more precise guess work from software

http://www.auto-ware.com/software/eap/eap.htm

BUT YOULL HAVE ABOUT 7 SCREENS OF DATA TO FILL IN CORRECTLY
eap1.jpg


eap2.jpg

eap3.jpg


eap4.jpg


LSAChart01.jpg
 
Re: My heads have been flow tested need help with a cam grin

I'm getting a better result with the same spread on the duration just lower;

110sa, 110icl
244intake, 259 exhaust
.600intake, .600exhaust

Is there an issue having that much spread in the duration at all? I am finding a pattern that anything less or more has a negative effect.
 
Re: My heads have been flow tested need help with a cam grin

Faytmorgan said:
I'm getting a better result with the same spread on the duration just lower;

110sa, 110icl
244intake, 259 exhaust
.600intake, .600exhaust

Is there an issue having that much spread in the duration at all? I am finding a pattern that anything less or more has a negative effect.
Click to expand...
its the DD2000 program parameters not the engine or reality or what it wants in reality, use the chart, its pretty much spot on most of the time, especially as the stroke and displacement increases
 
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