911 aircooled developments

[Axel84]

So with a 80.4 mm crank that would make it a 3.75L long stroke.

[Neil Harvey]

I don't give prices on the internet. That is not fair to the other vendors.

You can email me for those. Include info on the rest of your build along with your engine budget. Like I said, we may be outside of your budget.

The engine displacement varies with bore and stroke. We go out as far as 4.1L with the n80.40mm stroke. Those Pistons and Cylinders are in stock as well.

All 4.1L rotating parts are in stock.

[Axel84]

Originally Posted by Neil Harvey

Like I said, we may be outside of your budget.

Yes, you have mentioned twice now that your products might be outside of my budget.

I appreciate your concern for my financials, but I was just wondering about pricing for crank and cams.

if you have an email adress Im happy to get a quote in private.

thank you

[Neil Harvey]

Originally Posted by Axel84

Yes, you have mentioned twice now that your products might be outside of my budget.

I appreciate your concern for my financials, but I was just wondering about pricing for crank and cams.

if you have an email adress Im happy to get a quote in private.

thank you

neil@performancedevelopments.com

[Axel84]

thanks Neil,

Email sent.

[Neil Harvey]

An update of our "stuff".

A new early "Magnesium" pre 77 engine project we are in the middle of. We are going backwards it seems.

Project name is Project 24. The displacement is in 2300's cc. Enough to call it 2.4L. It has come about after several customers approached us to build an engine for their early cars that gave them the high RPM feel without spending the high cost of the 4V kit currently offered. We hope to give an engine that will produce acceptable torque, high RPM to make the HP expected and allow them to scratch that RPM itch they have. Not an inexpensive engine though. But hopefully for not much more than the 4V heads we can supply the whole rotating assembly and valve train. I really looking forward to this project as it really does stretch the brain with new tech in an older engine platform. Can it be done, etc. Will it produce the Torque we have calculated? This is the stuff that keeps me motivated.

All the Internals are lightweight, same for the Valve train. A lot of the parts we have developed for the later air cooled engines will carry over. Ti Rods, Ti Through bolts, Pistons, Valves, Springs and Rocker arms. The Rod show is one of our 991/992 GT3 rods with the sculptured beam section and internal oiling up to the pin. The new Rod will have the same sculptured beam with pin oiling but a lot smaller BE bore, BE width and reversed bolts.

Time and money will tell if we have done good.

Also, I have received many calls for the 3.2L 74.40mm Crank on our web site. I sold that years ago and have not had any time to update our outdated web site. That is happening now, finally.

I have added to our inventory two brand new 74.40mm cranks with the std minor upgrades added.

[Turbo_pro]

Originally Posted by Neil Harvey

David at Marine Crank makes a pretty nice product.

[PeteKz]

Neil, what length rod do you need to use with a 80.4mm crank?

[Neil Harvey]

Peter, there is no one length that has to be used. Many factors dictate the length.

Deck height, piston pin size and pin position in the piston, and the piston deck height you wish to use. I think from memory the longest rod we have used was 135.00mm.

The smaller bore engines may not allow such a long rod due to the dome Volume. Not quite sure, I would have to think about that one. The Piston forging may not allow the pin to be so high. Not something I know off the top.

[Neil Harvey]

An update on new parts we have been involved in. The air cooled parts list gets longer every day. Our air cooled projects all showed the basic issue with these engines. Potential and real air flow numbers reach a point where nothing more can be done to increase the flow.

There is a point where these engines are air limited in the current configuration. Valve sizes are max'ed out to allow fitment. Swapping out Exhaust size for Intake size allows only so much and its a slide and swing thing.

It has come down to what's next? What can we do? There are so many areas that can be addressed but what is really realistic? We do not have the room in the engine bay of these cars to move the Intake much. If we could, we could straighten out the ports. Cam and Rocker arm geometry dictates a lot as well.

So we have decided to focus on managing what air we do have, better. Currently management of the air we do have, flow is dictated by the cam spec and position of the camshaft in relation to the Crankshaft. This is where we are looking at changing and hopefully help the performance of these engines. In doing so, we have moved and changed the valve angles allowing for larger valves to be fitted. All of a sudden we seem to creating a Chevy Cylinder head. Still a lot to do and to figure out but this is our direction verses 4V's. Its hoped that this will help increase the potential torque and make our Project 24 make more sense.

In the meantime, the water cooled development continues. The 996/997 GT3 and Turbo engines now have a 6 butterfly Intake with their Plenums systems in progress. The 991/992 9A GT3 and Turbo engines have had their displacements changed with many parts, new Camshafts, "solid" valve motions added to the 991.1 GT3 engines with another less expensive "solid" version coming soon. Pictured are "solid" finger parts for the 991.1 and the new ITB system for the 996/997 engines. The actual system pictured is the Turbo version with the upper Turbo Plenum adapters fitted.

I need to lie down and take a nap! I'm often asked, when are you going to retire? Never, as the passion to do this stuff will never leave me.

[Old H2S]

Pretty work..

[PeteKz]

Re recreating Chevy cylinder heads: Hah, hah!

Like most engines, the cylinder head seems to be the most fertile ground for improvement. Keep us posted what you do there.

[winders]

Originally Posted by PeteKz

Re recreating Chevy cylinder heads: Hah, hah!

Like most engines, the cylinder head seems to be the most fertile ground for improvement. Keep us posted what you do there.

Xtreme is place to go if you are looking for 2 valve head performance. William Knight has some custom Xtreme heads designs that are even better and has some more ideas on even better 2 valve head designs.

[Neil Harvey]

Originally Posted by PeteKz

Re recreating Chevy cylinder heads: Hah, hah!

Like most engines, the cylinder head seems to be the most fertile ground for improvement. Keep us posted what you do there.

It became like that saying, "you can keep feeding a dead horse".

Valve angles limit the Valve sizes, only so much port size can be had and the air flow limits what can be turned into Torque.

Everyone has their magic wand. We were limited to what ours would do. Then ours stopped working so we decided to get another bigger one with bells and whistles.

I'm always puzzled with the HP numbers often shown. Having flowed both by bench and CFD, the air these heads can flow has a limit. If you calculate the amount of fuel required to make the stated HP number, the air flow required is beyond anything possible. Engines are mechanical objects where performance can be found on a hand held calculator.

When the air limit is reached you have to dig deeper and waive that new wand even harder. So, equipped with our new wand, we are looking at ways to mange the air we have better.

Chasing numbers that others "have" is a fools errand. Learnt that years ago. One of the first rules of engine development I was taught.

[PeteKz]

Originally Posted by winders

Xtreme is place to go if you are looking for 2 valve head performance. William Knight has some custom Xtreme heads designs that are even better and has some more ideas on even better 2 valve head designs.

Thanks for the reminder. I haven't chatted with William in awhile, so I should catch up with him.

[Neil Harvey]

It never ends. But I'm excited to continue our development of parts for the older air cooled engines. Way simpler than the water engine parts.

We have two in house air cooled "early engine case" projects underway at present. Project 24 is the small short stroke engine that is awaiting its crank. Stage one is with the std 2V head and SOHC set up. Depending on the outcome it may get the new head assy. This is going to be interesting. Either another dismal failure or it could turn out to be another avenue for others to follow.

The other is Project 3. Nothing special here. Probably been done before. We have not so its an opportunity to see what can be done. Both projects give us reason to develop new parts and both projects show there is room for continued development.

With more powerful electronics available to all of us now, we have the ability to change how these engines can be operated safely. We chase 1/2 of 1 HP, x 6 cylinders we get 3 HP. I'll take that all day. Incrementally we can gain significant performance. We have found that we do not need 5B oil pressure at high RPM. By controlling the Oil Pressure we can gain torque over the whole RPM range. With these engines we cannot control the pump as in late engines. But we can control the by pass. So far it has shown good gains. An easy task for electronics today. Just about every EFI system sold today has this ability.

Just one of the many things we are looking at.

[Turbo_pro]

Originally Posted by Neil Harvey

We have found that we do not need 5B oil pressure at high RPM. By controlling the Oil Pressure we can gain torque over the whole RPM range. With these engines we cannot control the pump as in late engines. But we can control the by pass. So far it has shown good gains. An easy task for electronics today. Just about every EFI system sold today has this ability.

Just one of the many things we are looking at.

I believe you can control the pump volume by choosing different pumps.
Weren't you the guy who argued that the GT3 oil pump in an air-cooled engine wasn't overkill?
Henry Schmidt was saying GT3 oil pumps in early air-cooled engines were "inappropriate" and you questioned the use of that terminology.
Oft times, experience has it's value.

[Neil Harvey]

"Oft times, experience has it's value".

So true. Many that contribute here have much more than I have with these Porsche engines. My start with Porsche was with the 962C race engine. Pretty late start compared to others here.

I have been doing this along time. I was very lucky and got to learn from some of the best ever. What was common from all I learnt from was an engine can never have enough Oil and Water pump.

Volume isn't the torque robber. Pressure is. Maybe you misunderstand what we are looking at.

[Turbo_pro]

Originally Posted by Neil Harvey

"Oft times, experience has it's value".

So true. Many that contribute here have much more than I have with these Porsche engines. My start with Porsche was with the 962C race engine. Pretty late start compared to others here.

I have been doing this along time. I was very lucky and got to learn from some of the best ever. What was common from all I learnt from was an engine can never have enough Oil and Water pump.

Volume isn't the torque robber. Pressure is. Maybe you misunderstand what we are looking at.

Perhaps your understanding of fluid dynamics isn't what you think it is.
Ultimately, pressure is the relationship between volume and ventilation.
In the most efficient system, the volume should only be slightly higher than necessary to fulfill oil demands and create a minimal amount of ventilation.
Ventilation in this case is a pressure regulator/check valve.
Spinning a pump that creates a higher than necessary volume will rob horse power.

[Neil Harvey]

Originally Posted by Turbo_pro

Perhaps your understanding of fluid dynamics isn't what you think it is.
Ultimately, pressure is the relationship between volume and ventilation.
In the most efficient system, the volume should only be slightly higher than necessary to fulfill oil demands and create a minimal amount of ventilation.
Ventilation in this case is a pressure regulator/check valve.
Spinning a pump that creates a higher than necessary volume will rob horse power.

In the case of these air cooled engines, I need the pump to spin at its designed speed to keep the scavenging at its most efficiency.

I have not disclosed what we are doing and how.