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HP limit / power to weight / pro built /low cost
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TOPIC: HP limit / power to weight / pro built /low cost

Re:HP limit / power to weight / pro built /low co 14 years, 1 month ago #8199

  • Palmr28
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Guys,

I am taking a wait and see with Eric on this one as well. I have read all or most of the comments here. The only thing I don't want to see happen is another version of Spec Miata. There are teams competing with $10,000 - 20,000 engines. (Yes the do exist in Spec Miata).

However there is a big difference between a $2,000-$3,000 engine "fresh rebuild" (new rods, crank, etc.); than boring out this and blueprinting that, in excess of $7,000 or so.

I feel that his issue is more of a socio-economic issue. I am currently building a car for next year and plan on rebuilding my engine through a shop, and by rebuilding I mean pretty much replacing just the things that need replaced.

So, I am willing to place $2,000 into my motor with labor to do this. I do not mind doing it myself, but I do not have all of the knowledge, nor the time; so that is why I pay.

It sounds like from my point of view, that you want to penalize the guys who don't have the knowledge to build their own engines, for the sake of guys who either do their own rebuilds, or guys who do not care if their engine has 150,000 miles on it, and they don't even touch it from the junk yard.

Am I correct?

If I wanted to race a car from the junk yard and not touch the engine, I would race a street stock, not a 944. Even in street stock "beat each other up" oval series, they let you replace the rods, etc.

Also if the engine claim thing catches ground, I am out..The engine claiming rules as previously mentioned divide the series and creates way more tension off of the track.

Re:HP limit / power to weight / pro built /low co 14 years, 1 month ago #8201

  • Big Dog
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I agree with many of Palmr28's comments. This should not be about who builds and engine. I do not see it as a discussion about engines at all. I think engines have been seized on as a "whipping boy". To me, if there is going to be some big discussion, it would have to be about all of the inhearent differences between various model years and models of our cars and I do not see that as practical or desirable.

As for the issue of 88 pistons vs older ones, it would seem that it is NO issue given that we have a 10.5 compression limit. This limit allows early pistons to shave the head more to get exactly the same compression of an 88 piston engine so there is NO issue to continue to discuss here, it seems to me. My goodness, how can there be talk about a "weight penalty" for 88 pistons when a shaved head engine will give exactly the same compression. We have much more variation in LSD's affecting performance than the 88 piston issue but we have all agreed that the LSD issue is finished.

The rule change of several years ago devastated 944-Spec in So. Cal. We do not need that again, EVER.

We have a basic set of rules that I believe work well. Other than minor tweaks, as we had last year, they should be left alone for many years into the future. Too much of this talk will drive away potential racers like Palmr28.

Big Dog
Jim Foxx

Re:HP limit / power to weight / pro built /low cost 14 years, 1 month ago #8203

Reply to Sterling Doc #8193

Just for the record, Tom Atteberry's engine was the only engine I worked on that was at the Nationals. I only re-assembled it. It was a dead stock, all original parts 1982 944 engine that was given to Cal Poly University Engineering department by Porsche in 1983. The only non-original parts were new bearings because students had scratched them during many dis-assemblies. Before going to the Nationals, it dyno'd at 7sOnly on their Dynojet242 @ 127 rwhp with a muffler and 132 rwhp without a muffler (the way it ran at Miller). Tom did not dyno his engine at Miller but others that did, LOST about 25 rwhp UNCORRECTED. When the Dynojet corrections were applied, most GAINED 1-2 rwhp. The dyno used at Miller was also a DynoJet242.

My opinions:

Your rules are very good. You have a 10.5/1 CR limit that was checked at Nationals. Keep them simple.

Don't allow chips or headers.

Allowing correction of cam timing change resulting from increasing compression within the 10.5/1 is a good idea but doing this via a crankshaft offset key is a BAD idea because it changes the balance shaft timing also. If you are going to do this, do it at the camshaft. I have spent literally hundreds of hours on my engine dyno developing SCCA ITS engines. The original factory camshaft timing is the best setting so...if someone wanted to make a "gain" by changing the timing to some other setting, let them. In racing these cars, the power between 4800 rpm and 6200 rpm is the most important. Peak power is almost always made between 5800 and 6000 rpm. If someone wants to advance his camshaft more than the factory setting, the peak power will be lower and peak torque will be under 4000 rpm where the engine is never used. If someone wants to retard his camshaft, the peak power might go up over 6000 rpm but he will loose peak torque and power below 6000 rpm. This also is not advantageous to the racer.

Your idea of a spec piston is a good one BUT it would not be cheap. It would not be cheap because the original factory aluminum piston is IRON plated over the aluminum and then TIN plated over the iron. This is done because aluminum will gaul when run on the exposed silicon aluminum bore of the 944/928. New pistons wouldn't correct the worn out cylinder walls of these 29 to 22 year old engines.
What would be your solution for the cylinder walls for these spec pistons. A solution to this problem will have to be found eventually as these cars age but perhaps the time isn't right now.

Your idea of a weight penalty is a poor one as any rebuild of a cylinder head eventually requires material removal to make it flat. You already have a 10.5/1 limit of compression ratio. All this penalty would do is make the hot combination an 85/2-87 engine with a shaved head and no weight penalty.

Jon Milledge

Re:HP limit / power to weight / pro built /low cost 14 years, 1 month ago #8233

  • cbuzzetti
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Hi Jon, welcome to the ZOO!!!!!
2018 NASA 944Spec National Champ
2018 NASA ST5 P2 944 Nationals COTA
2017 NASA 944Spec WSC P3
2016 NASA PTD-944 WSC P2
2015 NASA GTS1 Western Champion
2014 NASA 944Spec Western Champion
2013 NASA 944Spec So-Cal Regional Champion
2013 NASA 944Spec National P3
2010 NASA GTS-1 National Champion
2010 NASA 944Spec National P3
2010 NASA So-Cal 944Spec Regional Champion
2009 NASA 944Spec National Champion

Re:HP limit / power to weight / pro built /low cost 14 years, 1 month ago #8234

Jon, thanks for taking the time to check in. Your experience is definitely helpful here, and you points are well taken.
Eric Kuhns

National Director Emeritus

2007, & 2008 National Champion
2011, 2012 2nd

Re:HP limit / power to weight / pro built /low cost 14 years, 1 month ago #8253

  • jaje
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This might not be popular but the majority of us don't run the high compression engine (88 pistons or shaved heads)...so why allow the use of them in the first place?

Those with 88' pistons in their motors can easily sell them and net a nice stash of cash. Even those with shaved heads can sell those to normal 944 guys as they are always looking for that little bit more. If we can remove these variables we can even out the field more HP wise. It also might help get more racers to look at 944s b/c they don't need to have the rare high compression motor and it saves them ~ $1000 from buying these pistons or shaving the head by a professional shop...just for the idea of having to keep up with the guys who have them or we think have them. This is supposed to be a low budget spec series and this rule just does not fit with that spirit.
Joel
83 944 Spec (#74) - conflictedracer.wordpress.com/
Last Edit: 14 years, 1 month ago by jaje.
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