Merry Christmas to all, hopefully it finds you with friends and family.

Last week I removed the engine from my racecar for annual maintenance and thought that I would take some time to speak about the engine, and engine longevity in general. I know there have been great discussions on how long a modified 964 engine will last so I thought I'd post some facts about this particular engine.

The engine has been raced for 2.5 years and a total of 68.9 hours and if you are not familiar with the configuration, it is a 3.8l engine with factory pistons and cylinders, 12.0:1 compression, camshafts with over 317 degrees duration and .525" of lift set on an agressive centerline, 9M heads, MoTeC engine management controlled with no knock sensing, and run on Mobil 93 octane street fuel. We normally disassemble, inspect, and replace air cooled racing engines like this at 80 hours, but I'm going to run this engine another season and will probably add another 30 hours to it for a total of about 100 hours.

The engine condition looks good with no oil leaks. The leakdown on all cylinders is from a low of 1% to a high of 2% leakdown. And the valve adjust is within specification, but I did tighten up several exhaust valves to the lower end of the specification. Remember that Porsche has specified wider valve clearances for their RSR racing engines than the street version.

I'm a little disappointed that the engine is in such good condition because now I have to wait another year to rebuild the engine and install some new parts. The new engine will have a custom piston and cylinder and I'll up the compression ratio to 12.5:1. The new piston will be significantly ligher, and have some other modifications to it. I will be using some 9M valve train parts including their high lift rocker arms which will allow a larger camshaft to be fitted. Again, this camshaft will be designed based on the flow testing I did on the 9M head. I'll also be switching to titanium connecting rods from the steel Carrillo rods that are currently in the engine. I'm currently limiting the engine RPM to 7800 (I have run it to 8100) to improve the longevity of the engine. With the new engine, I expect to be able to run the engine to 8200rpm, again, on street 93 octane fuel.

When I reinstall the engine in the car for the next season, I'm going to lean the engine out slightly from where I'm currently at (.89 lambda on full throttle). This should help fuel mileage. I want to see how lean I can run the engine with no loss in performance and no risk to melting the engine. My race engine is tuned the same way I would tune a street car. At idle, even with the long duration camshafts, the engine idles at 1.0 lambda, and at light throttle it runs at 1.0 lambda. Only under high load does the engine get richer to help it run cool enough. The engine is also tuned for maximum timing with no room for error, it has the most timing the engine will take.

At the same time, we are in the process of converting on 964 street car to the 9M+1 (cams) package. This project will consist of a 9M MoTeC conversion box for the wire harness, a MoTeC M48 ECU with wide band lambda enabled and a Fabspeed exhaust. We will be testing a newly designed and improved 9M camshaft specific for the US market, and I'll be tuning the MoTeC for use on USA fuel, in this case 93 octane. So, you can call this the 9M USA version of their +1 package. The doner car is a 44k mile coupe. We have a second, almost identical project scheduled for later this winter, so this should be interesting.

 

Good news on your race engine, too bad you had to built strong reliable engine

Keep us posted on the 9M US version.

Merry Christmas!!

 

Geoffrey,

How does the Fabspeed compare with the B&B header with regard to primary length, ID, or anything else that may differentiate the two? If its' build quality matches that of my cat bypass, I'm sure it will surpass the B&B in that respect. You've used this header before?

Thanks,

 

I have not ever used any of the off the shelf street performance systems for the 964, so I cannot really comment on comparisons. I have used some Fabspeed products in the past on the Cup cars and seen them on other people's cars and know the quality and fitment is among the best. I have tuned street cars with Fabspeed products on them, but have not had opportunity to do comparison tests. You have to remember that my core business is the racing environment and the products are completely different with a different set of requirements. When I get the system in, I can certainly share the information you are looking for with you.

 

reading this makes me want to learn more about Porsche engine building and tuning related to Motec. Is there a book that is somewhat related that I can start reading to learn more?

Thanks

 

There are several resources for you. There are a number of books on tuning fuel injection at Barnes and Noble. You can attend one of the EFI classes which gives you theory (EFI101) and Practical experience (EFI Advanced). Information can be found at www.efi101.com. I helped put some of the material together and have taught the classes on the east coast.

 

Wow, Geoffrey. That has got to be the dream 964 engine that you are going to build. I don't even want to think about how much money it would cost to duplicate your engine (knowing what I just spent rebuilding my own 964 to more stock specs)....

 

thanks Geoffrey!

 

So what are you doing with your current P&Cs?

 

Thinking of going racing in GT4???

 

Maybe for 2009. I want to run this season in H and see what kind of competition I will have. Then I might seriously look at moving up to GT4. The only thing that I would really need is a motor and a racing ABS unit, at least to start with.

 

Well, that, and a properly geared transmission for an 8k engine, GT2 Evo uprights for proper roll center and bump steer management.

 

I have a 39,000 mile stock motor sitting in my garage. Maybe you should just build a new one from my core and sell me your old one?

 

We could do that, but I think that you might want to consider a 3.6l engine which allows you to run at2677 rather than 2785 with a 3.8l

 

The 3.8L formula allows me to pretty much leave most of my car intact, and so easily convertible back to a prepared class racer. I guess that once I see how this season shakes out, I will be in a better position to determine where I want to be.