How much power am I leaving on the table with my cam?
09-06-2013, 07:26 AM
#1
How much power am I leaving on the table with my cam?
Right now my combo is running really well for what it is. I'd imagine I might be able to sneak a mid 11 out of it as it sits. The camshaft I have now is a Clevite 246/246 @ .050. .53x/.53x INT/EXT. The lift numbers are with 1.6 rockers. It's a solid cam. I'd imagine the duration numbers would be higher as well with the 1.6 rockers but I'm not sure it'd make a difference. My question is, how much power am I leaving out there with a cam swap? Any suggestions?
See sig below for my combo.
Thanks,
See sig below for my combo.
Thanks,
09-06-2013, 10:57 AM
#2
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Car: 1984 LG4 Camaro
Engine: 350 Roller Motor
Transmission: Level 10 700R4
Axle/Gears: Strange 12 bolt 3.42
Re: How much power am I leaving on the table with my cam?
You are leaving quite a bit on the table with a non-roller cam in your motor.
A roller will allow a much more aggressive lobe ramp and at the duration you are using, be at 0.600" or greater valve lift with 1.5 rockers. Your heads flow about 290cfm at .600" lift. enough for almost 600hp in the right motor.
Keep in mind that lift is typically a TQ builder, while duration determines HP peak RPM and can definitely affect TQ on the low end. So you may be able to use a roller cam with 10 to 15 degrees less duration to get a similar HP reading, yet add more power down low - area under the curve.
A roller will allow a much more aggressive lobe ramp and at the duration you are using, be at 0.600" or greater valve lift with 1.5 rockers. Your heads flow about 290cfm at .600" lift. enough for almost 600hp in the right motor.
Keep in mind that lift is typically a TQ builder, while duration determines HP peak RPM and can definitely affect TQ on the low end. So you may be able to use a roller cam with 10 to 15 degrees less duration to get a similar HP reading, yet add more power down low - area under the curve.
09-06-2013, 03:05 PM
#5
Re: How much power am I leaving on the table with my cam?
Justin, I'll have to look when I get home. I know it has a 108 LSA. Have to double check the other specs.
09-09-2013, 08:35 AM
#7
Re: How much power am I leaving on the table with my cam?
You think with a Vic Jr and a 750 DP it'll do 118-119? That would be right where I want to be for MPH. I'm not too worried about ET at this point.
Last edited by zacharyhorn; 09-09-2013 at 11:23 AM.
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09-09-2013, 11:23 AM
#8
Re: How much power am I leaving on the table with my cam?
Alright Matt, I just scored the intake manifold. I will continue to use the 650 DP until I save coin for the carb. How much of an improvement will I see with just the intake upgrade? 117 mphish?
09-09-2013, 11:51 AM
#9
Re: How much power am I leaving on the table with my cam?
You will need to retune for that intake and likely play with timing again, but it should help
Also while your at it, once air fuel seems to be in line, play with the lash settings. Open it up to see if it wants less cam, close it up to see if it wants more cam. Do intake first then exhaust, from there you can get a better idea of what next cam will be. I'd like to see more intake lift but it should still run good with what you have
Also while your at it, once air fuel seems to be in line, play with the lash settings. Open it up to see if it wants less cam, close it up to see if it wants more cam. Do intake first then exhaust, from there you can get a better idea of what next cam will be. I'd like to see more intake lift but it should still run good with what you have
Last edited by Orr89RocZ; 09-09-2013 at 12:08 PM.
09-09-2013, 11:57 AM
#10
Re: How much power am I leaving on the table with my cam?
You will need to retune for that intake and likely play with timing again, but it should help
Also while your at it, once air fuel seems to be in line, play with the lash settings. Open it up to see if it wants more cam, close it up to see if it wants less cam. Do intake first then exhaust, from there you can get a better idea of what next cam will be. I'd like to see more intake lift but it should still run good with what you have
Also while your at it, once air fuel seems to be in line, play with the lash settings. Open it up to see if it wants more cam, close it up to see if it wants less cam. Do intake first then exhaust, from there you can get a better idea of what next cam will be. I'd like to see more intake lift but it should still run good with what you have
09-09-2013, 12:06 PM
#11
Re: How much power am I leaving on the table with my cam?
Ideally, the cam- if selected carefully- should be right when using the manufacturer's recommendations for lash and phasing (advance/retard vs. the crankshaft). But if there have been changes made to the engine or the cam isn't ideal, using a "Lash Loop" will point you in the direction the engine needs when replacing the cam.
The engine only responds to the actual movement of the valves. Since the valve cannot move until all the running clearance (valve lash) has been taken up, the amount of valve lash you use affects the engine's performance. For example, if you decrease the amount of (hot) valve lash, the valve will open slightly sooner, lift higher, and close later. This makes the camshaft look bigger to the engine, because of a slight increase of actual running duration and lift. If you increase the amount of (hot) lash the opposite occurs. The valve will open later, lift less, and close sooner.
This shows the engine a smaller cam with slightly less actual running duration and lift. You can use this method on a trial basis to see what the engine responds to and keep the setting that works the best. Just remember, the more lash you run, the noisier the valve train will be. If the clearance is excessive it can be harsh on the other valve train components. Therefore, for prolonged running of the engine we do not recommend increasing the amount of hot lash by more than +0.004" from the recommended setting. Nor do we recommend decreasing the hot lash by more than -0.008".
The engine only responds to the actual movement of the valves. Since the valve cannot move until all the running clearance (valve lash) has been taken up, the amount of valve lash you use affects the engine's performance. For example, if you decrease the amount of (hot) valve lash, the valve will open slightly sooner, lift higher, and close later. This makes the camshaft look bigger to the engine, because of a slight increase of actual running duration and lift. If you increase the amount of (hot) lash the opposite occurs. The valve will open later, lift less, and close sooner.
This shows the engine a smaller cam with slightly less actual running duration and lift. You can use this method on a trial basis to see what the engine responds to and keep the setting that works the best. Just remember, the more lash you run, the noisier the valve train will be. If the clearance is excessive it can be harsh on the other valve train components. Therefore, for prolonged running of the engine we do not recommend increasing the amount of hot lash by more than +0.004" from the recommended setting. Nor do we recommend decreasing the hot lash by more than -0.008".
http://www.crankshaftcoalition.com/w..._solid_lifters
09-09-2013, 03:21 PM
#12
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Car: 1984 Z28
Engine: Alky 360
Transmission: TH400, Freakshow 9.5"
Axle/Gears: 9" 4.71
Re: How much power am I leaving on the table with my cam?
FWIW...those darts (same as mine) are a bit lazy on the exhaust side, if you could come up with a set of 1.65's for the exhaust you could help them out a bit as well.
For reference I am running a voodoo 60103 with 1.65's, 215 darts, HVH intake and 750 AED.
For reference I am running a voodoo 60103 with 1.65's, 215 darts, HVH intake and 750 AED.
09-09-2013, 07:18 PM
#13
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Car: 84 camaro
Engine: HRE 355
Transmission: th350
Axle/Gears: 4.56
Re: How much power am I leaving on the table with my cam?
Also...the intake should be portmatched at least slightly to the heads/gaskets....and id say the 650 dp will handle it. I ran 10.1s @131mph with a 650.
Also...the cam is lacking, but there are other options...did you lock out the timing in the distributor? Have you done awah with power valves in carb?
All of these little things will help 60' and ultimately mph.
Also...the cam is lacking, but there are other options...did you lock out the timing in the distributor? Have you done awah with power valves in carb?
All of these little things will help 60' and ultimately mph.
09-10-2013, 09:19 AM
#14
Re: How much power am I leaving on the table with my cam?
Also...the intake should be portmatched at least slightly to the heads/gaskets....and id say the 650 dp will handle it. I ran 10.1s @131mph with a 650.
Also...the cam is lacking, but there are other options...did you lock out the timing in the distributor? Have you done awah with power valves in carb?
All of these little things will help 60' and ultimately mph.
Also...the cam is lacking, but there are other options...did you lock out the timing in the distributor? Have you done awah with power valves in carb?
All of these little things will help 60' and ultimately mph.
09-10-2013, 12:54 PM
#15
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Car: 1990 IROC
Engine: Rebuilt L98 with H/C/I/Carb
Transmission: TH350 with ATI Treemaster
Axle/Gears: 7.5 with 4.10's
Re: How much power am I leaving on the table with my cam?
I think the Jr. might pick up some horsewpower, but you will lose enough low RPM that the car will probably go slower. Unless, of course, you are switching rear gears and winding that engine to 7000RPM or so. Based on the cam specs, I would assume that's about where it wants to be shifted.
09-10-2013, 01:03 PM
#16
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Car: 1984 Z28
Engine: Alky 360
Transmission: TH400, Freakshow 9.5"
Axle/Gears: 9" 4.71
Re: How much power am I leaving on the table with my cam?
I read through your thread. I like it. Any numbers out of your combo? I want to see mid 11's out of the head / cam combo I have now.
When I do get the single plane intake I will slightly port the runners to match my gaskets. I wasn't sure if I would be giving up power down low going from the RPM to the Vic Jr. The timing curve I'm using is 24 degrees initial and 36 degrees in by 2500 RPM. I do drive it quite a bit on the back roads and on the street so I don't have it locked out. I think I still have the 65 power valve that came with the car. I didn't play with jetting yet as I am waiting for my buddy to come back from Nevada so we can tune with a wideband. That is a bad *** SBC you've got there BTW.
When I do get the single plane intake I will slightly port the runners to match my gaskets. I wasn't sure if I would be giving up power down low going from the RPM to the Vic Jr. The timing curve I'm using is 24 degrees initial and 36 degrees in by 2500 RPM. I do drive it quite a bit on the back roads and on the street so I don't have it locked out. I think I still have the 65 power valve that came with the car. I didn't play with jetting yet as I am waiting for my buddy to come back from Nevada so we can tune with a wideband. That is a bad *** SBC you've got there BTW.
Only been 1/8 mile so far with only 7 passes on it. Best so far 7.25 @ 92.8mph, 1.56 60' time.
09-10-2013, 04:23 PM
#17
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Car: 84 camaro
Engine: HRE 355
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Axle/Gears: 4.56
Re: How much power am I leaving on the table with my cam?
Zach...i drove my old street car alot with the distributor locked..but you do what youre comfortable with. Power valves oopening and distributor springs are all time variables that affect the acceleration.
Im only giving ideas :-)
Im only giving ideas :-)
09-10-2013, 05:49 PM
#18
Re: How much power am I leaving on the table with my cam?
i feel like those effect consistency more than actual acceleration...at least in my experience.
but my experience was on a much slower combo...these things may have a larger effect on faster cars.
but my experience was on a much slower combo...these things may have a larger effect on faster cars.
09-12-2013, 08:34 AM
#20
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Car: 67 ******mobile
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Re: How much power am I leaving on the table with my cam?
Also prefer to have a curve to the dist. to ea his own
IMO you need more gear like a 4.11/26 in tire something like that
Im a firm believer in giving some work to the intake too.
Not every car will benefit from it but in the right spots yours can
Got a nice solid roller just sitting here, too.
Wouldnt mind a little more carb also. 750 HP would be about right double pumper the way to go. Not saying you couldnt jet the 650 up you can but if you get into turning some rpm the 750 will give it upstairs.
IMO you need more gear like a 4.11/26 in tire something like that
Im a firm believer in giving some work to the intake too.
Not every car will benefit from it but in the right spots yours can
Got a nice solid roller just sitting here, too.
Wouldnt mind a little more carb also. 750 HP would be about right double pumper the way to go. Not saying you couldnt jet the 650 up you can but if you get into turning some rpm the 750 will give it upstairs.
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