944 16V twin CAM GEARS mod
12-05-2005, 11:17 AM
#31
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How do you know what I'm building?
How did I start thinking about this?
I was down in NYC picking up part of a 944 turbo motor, and the guy has a 3L 16V turbo motor with these two cam gears. It sparked an interest because I figure that there is a semi easy way to do it. And I think that there might be.
I dunno exactly what kinda motor I'm gonna build, I've got the parts to pretty much make whatever - 2.5L 16V, 2.5 8V turbo, 3L 8V or 16V turbo or N/A.
One things for sure, if I build a turbo motor... the turbo WILL be on the passenger side!
Maybe I should build a frankenstein backyard special (motor)... just for you purists!
How did I start thinking about this?
I was down in NYC picking up part of a 944 turbo motor, and the guy has a 3L 16V turbo motor with these two cam gears. It sparked an interest because I figure that there is a semi easy way to do it. And I think that there might be.
I dunno exactly what kinda motor I'm gonna build, I've got the parts to pretty much make whatever - 2.5L 16V, 2.5 8V turbo, 3L 8V or 16V turbo or N/A.
One things for sure, if I build a turbo motor... the turbo WILL be on the passenger side!
Maybe I should build a frankenstein backyard special (motor)... just for you purists!
Last edited by 300guy; 12-05-2005 at 05:36 PM.
12-05-2005, 01:34 PM
#32
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Originally Posted by 300guy
How do you know what I'm building?
How did I start thinking about this?
I was down in NYC picking up part of a 944 turbo motor, and the guy has a 3L 16V turbo motor with these two cam gears. It sparked an interest because I figure that there is a semi easy way to do it. And I think that there might be.
I dunno exactly what kinda motor I'm gonna build, I've got the parts to pretty much make whatever - 2.5L 16V, 2.5 8V turbo, 3L 8V or 16V turbo or N/A.
One things for sure, if I build a turbo motor... the turbo WILL be on the passenger side!
Maybe I should be a frankenstein backyard special (motor)... just for you purists!
How did I start thinking about this?
I was down in NYC picking up part of a 944 turbo motor, and the guy has a 3L 16V turbo motor with these two cam gears. It sparked an interest because I figure that there is a semi easy way to do it. And I think that there might be.
I dunno exactly what kinda motor I'm gonna build, I've got the parts to pretty much make whatever - 2.5L 16V, 2.5 8V turbo, 3L 8V or 16V turbo or N/A.
One things for sure, if I build a turbo motor... the turbo WILL be on the passenger side!
Maybe I should be a frankenstein backyard special (motor)... just for you purists!
12-05-2005, 01:36 PM
#33
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Originally Posted by jonnybgood
This would be a waste of time on a high compression 16v NA engine. The cam gear pulley has three mounting slots to allow for some adjustment of intake to exhaust cam timing. The FSM calls for 1.4mm lift on #1 intake valve. You can adjust this value out to 2mm or down to less than 1.4mm with the pulley slots. This will have the effect of shifting the torque curve up or down the RPM range. It has been said that above 2mm the engine runs poorly. I currently have mine set at 1.77mm and have noticed what seems like more torque at lower RPMs. It is not a great deal of change.
Anyway any adjustment more than the stock pulley slots will result in valve contact with the 10.9:1 compression pistons so what is the advantage on a NA? IMHO you would only be adding more points of potential failure for minimal gain. Don't you think the tuners at Porsche figured out the optimum valve timing for these engines? Seems easier and cheaper to remove the cam cover once in a while and change the f#cking pad! not trying to be nasty here just making a point.
If you are building a turbo 16v like Andy wants to do then lower compression pistons could be used and you could move the timing where ever you want. So it makes sense that you would do this on a turbo engine as in Moonboy's picture.
Anyway any adjustment more than the stock pulley slots will result in valve contact with the 10.9:1 compression pistons so what is the advantage on a NA? IMHO you would only be adding more points of potential failure for minimal gain. Don't you think the tuners at Porsche figured out the optimum valve timing for these engines? Seems easier and cheaper to remove the cam cover once in a while and change the f#cking pad! not trying to be nasty here just making a point.
If you are building a turbo 16v like Andy wants to do then lower compression pistons could be used and you could move the timing where ever you want. So it makes sense that you would do this on a turbo engine as in Moonboy's picture.
The downside is loosing the VarioCam which would be nice to keep but that can of course be up to the builder.
12-05-2005, 02:02 PM
#34
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I went and reread the thread before I posted and you are correct I don't know what you are building. I still think eliminating the tensioner by installing several other points of failure would not be a gain. Especially when the pad is easily replaced.
Have fun on what ever you build.
Have fun on what ever you build.
12-05-2005, 04:00 PM
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unfortunately the toyota cam gears are a little bit bigger than the custom made gears (36 vs. 34 teeth).
Someone made a good point about lowering the engine to make up for it.
Its too bad that we havent had any input from the "pro's". I was hoping that whoever makes those custom cam gears (some dude from Cali ?) would give us some insight about how he made them.
Hey Brain aka "the edge" - where are you located?
I've been reading about your megasquirt stuff - I want to come see your car!
Colin (kingston, Ont.)
Someone made a good point about lowering the engine to make up for it.
Its too bad that we havent had any input from the "pro's". I was hoping that whoever makes those custom cam gears (some dude from Cali ?) would give us some insight about how he made them.
Hey Brain aka "the edge" - where are you located?
I've been reading about your megasquirt stuff - I want to come see your car!
Colin (kingston, Ont.)
12-05-2005, 04:10 PM
#36
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Originally Posted by 300guy
unfortunately the toyota cam gears are a little bit bigger than the custom made gears (36 vs. 34 teeth).
Someone made a good point about lowering the engine to make up for it.
Its too bad that we havent had any input from the "pro's". I was hoping that whoever makes those custom cam gears (some dude from Cali ?) would give us some insight about how he made them.
Hey Brain aka "the edge" - where are you located?
I've been reading about your megasquirt stuff - I want to come see your car!
Colin (kingston, Ont.)
Someone made a good point about lowering the engine to make up for it.
Its too bad that we havent had any input from the "pro's". I was hoping that whoever makes those custom cam gears (some dude from Cali ?) would give us some insight about how he made them.
Hey Brain aka "the edge" - where are you located?
I've been reading about your megasquirt stuff - I want to come see your car!
Colin (kingston, Ont.)
12-05-2005, 04:34 PM
#37
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haha - I guess so. I dont think that I'll be out there anytime soon.
I'm gonna keep following your megasquirt stuff... getting rid of that AFM would be amazing.
Also... its too bad that the motronic code is such a secret. I am able to custom tune my 300zx with the original ECU (different injectors, larger MAF, raising rev limitter, custom fuel/timing maps) ... it would be SWEET to be able to do this to the 944 DME. I think that i know where the fuel/timing maps are... but I have no idea where the injector k value is, or the VE tables for the AFM.
I'm gonna keep following your megasquirt stuff... getting rid of that AFM would be amazing.
Also... its too bad that the motronic code is such a secret. I am able to custom tune my 300zx with the original ECU (different injectors, larger MAF, raising rev limitter, custom fuel/timing maps) ... it would be SWEET to be able to do this to the 944 DME. I think that i know where the fuel/timing maps are... but I have no idea where the injector k value is, or the VE tables for the AFM.
12-05-2005, 05:04 PM
#38
Drifting
to everyone opposed, why is everyone with a porsche so afraid of change? why does it have to be that this 25 year old technology is a modern marvel only to be outdone by porsche itself? why when someone posts that another car is faster than a 944, the excuse comes up that the car is old, and the technology is old, but yet, a hotrodder with a new idea is stupid and wasting time to overcome the old technology by incorporating new?
the only "negative" comment i have about doing this modification is: dont lower the engine in the cradle. there have been maybe 3 guys posting within the couple years ive been on the board that have busted an oil pan, and ruined there engine. what if you decide to lower the car?
i say, instead, just put a damn bump in the hood. the damn hood on a 944 is too plain......porsche made the 924 more interesting by adding flares to the side of the car and renaming it......why did they leave the hood alone? just put a bump in the hood, and make it match the style of the car.
quit being afraid of change porsche people!!!!!
the only "negative" comment i have about doing this modification is: dont lower the engine in the cradle. there have been maybe 3 guys posting within the couple years ive been on the board that have busted an oil pan, and ruined there engine. what if you decide to lower the car?
i say, instead, just put a damn bump in the hood. the damn hood on a 944 is too plain......porsche made the 924 more interesting by adding flares to the side of the car and renaming it......why did they leave the hood alone? just put a bump in the hood, and make it match the style of the car.
quit being afraid of change porsche people!!!!!
12-05-2005, 08:25 PM
#40
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Discouraging bad ideas is not fear of change. For a full-on race motor with custom cams, I could see sprocketing the intake cam. Doing all that work to 'fix' the tensioner system, which needs a trivial amount of attention in the first 200K miles? Nah.
-Joel.
-Joel.
12-06-2005, 01:06 AM
#41
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Originally Posted by kennycoulter
to everyone opposed, why is everyone with a porsche so afraid of change? why does it have to be that this 25 year old technology is a modern marvel only to be outdone by porsche itself? why when someone posts that another car is faster than a 944, the excuse comes up that the car is old, and the technology is old, but yet, a hotrodder with a new idea is stupid and wasting time to overcome the old technology by incorporating new?
The point of my post earlier was based upon the stated purpose of eliminating the tensioner system. My opinion is still that the work and effort is not worth the benifit.
As far as lowering the motor as somebody suggested, well that will result in worn TT bearings or a bent drive shaft if you really are going to lower the motor a full inch. Just my opinion. These cars are great for creating the car you want. Have fun.
12-06-2005, 01:15 AM
#42
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Originally Posted by jonnybgood
As far as lowering the motor as somebody suggested, well that will result in worn TT bearings or a bent drive shaft if you really are going to lower the motor a full inch. Just my opinion. These cars are great for creating the car you want. Have fun.
12-06-2005, 08:41 AM
#43
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also.
im not sure if this is the right thing. so dont hold me to this.
but in one of the turbo books ive read. its well accepted that if you have knock that you retard the timing.
but the book said (here it is.) that actually retarding the exhaust cam is way more effective and you will not loose near as much HP as if you retard the timing with the sparkplug.
the book also had LOADS of info on cam timing and if you guys wnat i can scan a few pages to show you the benefit.
also. i would LOVE to hear an S2 engine with a huge overlap. man. that thing would sound so awesome at idle and just scream up high!
im not sure if this is the right thing. so dont hold me to this.
but in one of the turbo books ive read. its well accepted that if you have knock that you retard the timing.
but the book said (here it is.) that actually retarding the exhaust cam is way more effective and you will not loose near as much HP as if you retard the timing with the sparkplug.
the book also had LOADS of info on cam timing and if you guys wnat i can scan a few pages to show you the benefit.
also. i would LOVE to hear an S2 engine with a huge overlap. man. that thing would sound so awesome at idle and just scream up high!
12-06-2005, 05:26 PM
#44
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Originally Posted by theedge
No. The torque tube bolts to the bellhousing. Impossible to bend.
Well, something I would not do to my car....
12-06-2005, 07:52 PM
#45
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campeck...
this dude in NYC had a 16V turbo 968 motor in his 944 turbo. It had web cams, the ones that it says "check all clearances"... I guess the lobe is so big that it hits the stock casting.
It sounded pretty sweet. Quite a "lope" at idle, but it DID idle without stalling. Too bad I didnt get to go for a ride.
this dude in NYC had a 16V turbo 968 motor in his 944 turbo. It had web cams, the ones that it says "check all clearances"... I guess the lobe is so big that it hits the stock casting.
It sounded pretty sweet. Quite a "lope" at idle, but it DID idle without stalling. Too bad I didnt get to go for a ride.