camshaft input please - Solex or E for a 3.2

[haycait911]

assembling my 3.2 ( 95mm JE and carrera crank) and am now second-guessing my cam choice.

I want a torque monster, not interested in HP past 6K rpm, but want tons of mid-range pull. trying to save a few bucks so I was going to use some nice solex cams I have in stock. or, I also have some 72-72 E cams as well.

doing 36mm intake ports, stock exhaust ports, Webers, headers.

any thoughts? my main concern is that neither has enough lift for a 3.2. are my concerns valid? or does high-lift only come into play at high rpm/high HP?

any input much appreciated. thanks, Don.

( John.............. are you out there )

[fred cook]

For more low to mid range torque, I have always heard that a higher lift with moderate duration cam is what you should use. For hp up top, then you would want the cams with longer duration. I think the amount of overlap is what makes the difference. I am about to build my 3.0 into a 3.3SS. I also like the pull of good midrange torque so I have decided to use 964 cams along with CIS injection and twin plug Carrera heads. Good luck with your build!

[hcoles]

I suggest asking John (Camgrinder) - he will likely know what works well.

[haycait911]

Originally Posted by hcoles

I suggest asking John (Camgrinder) - he will likely know what works well.

I sent him a link to this thread so I'm hoping he'll chime in. he came up with a grind for my last engine that was amazing.

[camgrinder]

I'm not a big fan of 47mm housings on an engine made for 49mm's. But out of the 2 sets of cams you have, I would choose the E's. I assume 40mm Webers and no more than 9.5-1 compression.

We could also do something custom..
How about the Dc10 on a 108 lobe center. If you find some used turbo cams, I should be able to grind them with a decent base circle size. A little milder than your last set of cams. Meaning more mid range but less above 6000 rpm.

Duration and lobe center have a much greater effect on power and powerband location than valve lift.

[PFM]

Haycait,

Not to undercut John if you have access to a flow bench you might consider buying PipeMax software. It will give you some good input on lift duration port size and required air flow all in one package. The cost is very nominal. After you plug in some numbers you will likely end up talking with John for a custom grind. There are lots and lots of things to consider on both the heads and the cam. If a slightly larger valve is in the possible range a lower lift cam will work very well.

Stay tuned,

PFM

PS I get nothing from Larry at PipeMax for the recommendation.

[cmcfaul]

What kind of CR are you running? I believe the Solex will sacrifice some CR for VE (volumetric Efficiency). Just somthing to consider.

Chris
73 911 E

[haycait911]

Originally Posted by camgrinder

I'm not a big fan of 47mm housings on an engine made for 49mm's. But out of the 2 sets of cams you have, I would choose the E's. I assume 40mm Webers and no more than 9.5-1 compression.

We could also do something custom..
How about the Dc10 on a 108 lobe center. If you find some used turbo cams, I should be able to grind them with a decent base circle size. A little milder than your last set of cams. Meaning more mid range but less above 6000 rpm.

Duration and lobe center have a much greater effect on power and powerband location than valve lift.

aahhh........ John, you tempt me. I'm in an awkward spot. no $$ left but I really don't want to cheap out on the heart of the engine.

some options.

1. use the E cams I have.

2. use the same cams as last time ( I have some SC cams in stock)

3. something new.

for this engine I want all the torque I can get, and then some. my 3.0 engine HP peak was 5800. here's the dyno for my 3.0 for comparison.



I'm not really looking to run over 6K rpm anyway so I'd like to get as much benefit from a fat torque curve. I've got 9.5 JE's, 95mm bore and a carrera crank, 36mm intake ports, stock exhaust ports, weber 40mm on very tall manifolds.

John, is there anything you can do with my SC cams? I'm looking for some turbo cams but I'd like to drive this car someday soon-ish. do you have some turbo cores in-stock? pm me if you like with any options you think would work.

[camgrinder]

Originally Posted by PFM

Haycait,

Not to undercut John if you have access to a flow bench you might consider buying PipeMax software. It will give you some good input on lift duration port size and required air flow all in one package. The cost is very nominal. After you plug in some numbers you will likely end up talking with John for a custom grind. There are lots and lots of things to consider on both the heads and the cam. If a slightly larger valve is in the possible range a lower lift cam will work very well.

Stay tuned,

PFM

PS I get nothing from Larry at PipeMax for the recommendation.

I have a few V8 type customers that use pipemax. Works very good. I should spend some time and model a known 911 engine combo and see how it works.

Most engine modeling program are based on water cooled, wedge head, empirical data. When I get a call from someone wanting .700" valve lift and 15 degrees more exhaust duration on a 911 cam, first question I ask is "Do you have desktop dyno?".

[camgrinder]

Sent a PM

[PFM]

John,

You made me laugh with the Desktop Dyno comment.... PipeMax has worked quite well for several Air Cooled projects not all Porsche, I have also reviewed the info with other engine builders and had good feedback. Do you have the software? It hit a 3.0 I ran as a test right on the money IF you shot for the low numbers in the HP and TQ listing. The lift and curtain area information is pure math. Header length and diameter is what the program is really for the rest is just extras added in over time. Flow bench information shows very good comparisons.

Stay tuned,

PFM