Couple laps in my stock (minus studs and gas pedal) from High Plains Raceway today. Still need to gain some confidence in the car and more in the driver ;) Can't wait to be done with my build... you guys are having too much fun without me.

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Nice job Eric and Tom! I'm glad we have you guys looking out for us.

Lots of variables between motors, Dynos, weather etc. that said, 203rwhp smells like fish. Car in question may have had a very valid reason for refusing inspection. #2.7L??
:matchup:

Careful Scrutiny of the podium cars is wise in Spec racing.

Great stuff Tom! I'm continuing on my build and your videos are always good inspiration.

How about wheel bearings. Do you have a routine for changing those out? From what I've read, it sounds like yearly replacement independent of what condition they may be in.

Nice plug for the junk yard :-)

What is allowed in an engine rebuild? Can you custom make the rings?
What limits are there on the valve job.

IMS retrofit isn't going to get you anything.

Anything else would seem to be illegal.

What weight oil do you guys run?

Could you alter the cam to exhaust timing on the vario-cam by displacing a tooth and still not have interference but gain anything?

Note I don't race spec boxster -- but I've been involved in a few M96 rebuilds and its not hard to accidentally alter the vari-cam timing during install (but I've always caught it :-).

Mike

Yeah, some of the high mile motors run good after being loosened up!

There aren't very clear/good/complete rules when it comes to the rebuilds like you would find in Spec Miata or a class run by a more professional organization, unfortunately. So the term "stock spec" really covers most of your questions. At the least, we're trying to make sure everyone is using stock components.

We're supposed to be using stock Porsche pistons and rings. No aftermarket pistons/rings built to same size or anything like that. I have not seen limitations on valve jobs, other than the valves need to be stock.

Oil weight is up to the competitor/engine builder, there is no stock spec. I use 0w-50 Mobil 1 Racing oil.

You cannot legally alter the cam timing. However, I'm sure there are some that do. It is not something I've done or experimented with so I can't speak to the specific advantages.

It was questionable to some competitors as to why someone would rebuild a motor that didn't have any apparent issues. Once new motor was in, car set the track record and pole at the next two attended events. There was a competitive field full of multiple race winners all within a few tenths of each other and then one car a full second ahead. Then it popped high on the dyno, 5% higher than the rest. Then declined inspection and went home instead. Maybe he was frustrated and felt unfairly criticized, but some will draw their own conclusions.

It has come to my attention that my statement above has been cherry picked to support ones own personal thoughts and I just want to clarify...
A gentleman asked specifically about valve job rules and I replied above, that there are no specific rules in the rule book other than ''stock'', unfortunately. Some that wish to read into that assume that meant I would manipulate a valve job... that's not the case, just you hearing what you want to hear. It was a reply to a question specifically about valve job specifications.
As referenced just beforehand, a rule set like spec Miata actually has several pages about engine internal specifics, like posted below.
I did not say ''I have not seen limitations'' because I have exploited them, I said that because there are no posted values of limitations...

Short of buying new cylinder heads for every rebuild, there are modifications that need to be completed on any regular standard engine build. This is supposed to be cost controlled spec racing and engine rebuilding is part of it. There should be rules with values about plunge cutting and valve jobs and decking heads like any other reasonable spec but BSR is not at that level of precision, yet.

People will believe what they want... even with several independent dyno runs at several tracks back to back against other cars right out of qualifying. We know what the cars are running HP wise across the field because they have ramped up dyno testing and that is a big step forward.

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Eric,

Never thought otherwise -- basically having a beer discussion over the net :-)

I'm building a pair of SP-1s, so arguably my question is mute to me. However I do track a Boxster S and I have either rebuilt or been a part of about a dozen rebuilds of these engines and I was trying to envision how the HPs could vary.

Note I'm a EE and shade tree mechanic hack not a professional engine builder -- so this is more of a thought exercise for me.

Mike

I was reading up on the VarioCam -- as I understand it, the solenoid opens up from about 3K-5K, and is shut off above and below. If it wasn't working "properly", you would have different engine behavior. I'm not sure if that would be better or worse overall. I have to think there would be a tradeoff if it was to be engaged all the time as an example.

Mike

Thanks, I wasn't referring to you at all. It's a good question and anyone that has built an engine would know that cylinder head servicing is part of it. You can't rebuild a head to exact stock originally delivered specs and still successfully service it. Replacing cylinder heads with new every time adds another $8k to an engine rebuild and a terrible idea for cost controlled spec racing. Porsche dealership service departments and factory re manufactured engine program all service heads in similar ways within certain tolerances. Even if you ordered a rebuilt crate 2.5L engine from Porsche, the cylinder head has been serviced. Order up a rebuilt cylinder head from Porsche and that has also been serviced. Unfortunately, those tolerances are not really public info or written in our rule books so there is no guidance as to what acceptable "stock" range actually is. So when I said, "I have not seen limitations", that's what I meant. Not "there are none so it's wide open for porting and polishing and ceramic coatings and flow bench testing." As you can see, some spec classes do have a handle on such things, and Boxster Spec is not one of them.

Better to be working as designed, for sure. These solenoids and tensioners fail from time to time and there is an overall performance loss.

With all of the engine discussion(!!), I wanted to reply to this by saying that I replace the wheel bearings very two years. Some do it more often, some less and some only when they start to fail. There doesn't seem to be a full consensus that I am aware but most people racing multiple years do get into some type of routine.

Let me start this post by saying that taking your car to the track can be a humbling experience. It is still one area where personal performance is easily measured and easily compared with others. And sometimes, whether you like it or not, the truth just stares back and gives you the middle finger.

Yesterday was one of those days for me.

Well, let's talk about the positive things first; the San Diego region PCA hosted an excellent event at Buttonwillow raceway with both racing and time trials on a beautiful 70F sunny day in middle of Central California farmland.

I also had to opportunity to meet fellow Forum member JayG and his son who were there for the time trial and I got a personal and upclose look at Topless' shiny white Cayman. That Cayman is a beautiful car!

Now, the reality check: I was S-L-O-W. As in 12 seconds off the pace in the first practice session. 12 seconds!!

I got better during the second practice session and took off 5 seconds. Then took another 5 seconds off in the third/qualifying session.

So I was only a few seconds behind the leaders pace right? Unfortunately, no. By the time that I caught up those 10 seconds, the leaders had taken 3 more seconds off of their times. And it wasn't just one or two drivers, 9 of the 13 cars in the Spec Boxster field were 3-5 seconds per lap faster than me!

During the race, I started well and kept up with the race pace (which is almost always slower than qualifying) until the halfway point when I started to fade rearwards. I think that I finished 12th or 13th. I say 12th or 13th because if I actually look it up, then I would know for sure and would have to say that I finished last. Ouch. That hurt.

To sum it up; I sucked and got my assed kicked.

The video should be pretty good since there was a lot of close racing in the first half of the race. I'll edit it quickly and get it posted.

P.S. I did not race today due to the rain that rolled in this morning.

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Good to see you out there Tom, sorry it wasn't a better day for you. We all have a few bad days at the track but the good ones keep sucking us back in. :) Racing ALWAYS beats sitting at home watching Oprah reruns.

Dan and I managed to have a pretty good weekend. We both posted personal best times as the track seemed to get faster all weekend. The Cayman works better at BW than Chuckie because there are more long straights so she can stretch her legs a bit. Still way too softly sprung so I have some work to do over this end of season break. Looking forward to 2016 with fresh tires, suspension, and weight loss.

Sometimes you're the windshield, sometimes you're the bug. It was your day to be the bug. Sorry to hear you had a less than stellar day.

Go get the next one. :cheers:

Great meeting you finally as well. Sorry you had a bad day. I enjoyed watching all you guys with the running start. Real racing!

It was my first time at Buttonwillow. Its a challenging and fast with the long straights. Got into the low triple digits in 4th. Especially fun is the 4th to 2nd downshift at Star Mazda and then fast into the esses Sunset and the front straight. woohoo!

The rain came in the beginning of my 2nd session on Sunday. Got a good lap in and then started a bit of sliding in the corners as the rain started coming down faster. Brought it in, there is always another day...

All in all a great fun weekend.

THStone, you running an external oil cooler or Accusump?

Currently, I am not using either of those. I do plan to install the TechnoSump (2 qt deep sump with horizontal tray) over Thanksgiving.

Thanks. If you don't mind, let me know how it goes. I've been evaluating the engine cooling options out there and have not been able to find a definitive answer ... probably user dependent ;)

• I've heard the S cooler only provides marginal cooling improvements
• With an accusump type setup, I've heard that an oil leak will result in the entire system purging itself
• External setups can be complicated and expensive, and cooler location can expose it to damage

Wish there was just an easy, straight-forward, proven solution :)