911.racer Posted September 18, 2011 Share Posted September 18, 2011 OK, so it is not exactly a new build. And, please, do not take this as a whack at any of the rules just becuase I am questioning them. I am trying to understand them as clearly as possible as not to take any mis-step in my re-assembly. I understand the point behind the rules is to provide ample modifications at a basic cost. A great formula. One of the reasons I am even writing this. To introduce myself, I run in Great Lakes region and have up until this point driven a 911 in gts 3,4,and 5. And I drive the Polizei 944 in 944cup (originally) and in GTS1 (I did alright at the championship race this year). My goal for the winter is to get my 911 together as my primary race car and to de-tune Polizei from GTS1 to 944 Spec. The reason behind the detuning is becuase of the high $ investment I have in it I can not carry the cost of two high $ cars. Anyway that said, I have a few questions about rules. Crankshaft The rules allow an additional rod hole for oiling. One of the successful modification that we had made with the extra cross hole was to enlarge the oil feed hole between the rod and main bearing, then tap where the plug was and install a threaded plug instead of crimped one. We found that the extra hole does not do much good without the larger feed hole to feed it. Is that permitted. Engine and Transmission mounts Did I miss it, or can we not run solid engine and transmission mounts. If not, why. They are not very expensive and create one less thing that can fail. IAC Motors I have never run an idle air control motor. Is an IAC part of the 'emission system' that can be removed ? 17mm vs 19mm ball joints This is just a question. Why can we not use the larger 19mm when rebuilding if they are stock height. Yes, they add cost over just finding some more stock arms in good shape, but they offer no performance advantage, so why not allow them for people who want to spend a little extra to have stronger ball joints. (this coming from a guy who snapped a 19mm one this year) Short shift trans linkage Why can't we add these. They are cheap and easy to install. Lexan hatches I am in the 'do not change the rules' club. I have had both and I am thrilled to be going to a class that does not use them. They are flimsy at best and a pain in the butt. I am constantly waiting for mine to pop out and blow away on track even though I have straps running the length of the hatch. I would rather see permission to run fiberglass hoods (20lbs savings) instead of lexan hatchs. Springs and torsion bars What is some of the best combinations that are being used here. (primarily the torsion bars) I do not mind changing front springs, but would really like to start out with the right size torsion bars. I am sure that I will have more questions, but this is it for now. Thanks Ed Baus Quote Link to comment Share on other sites More sharing options...
944-Spec#94 Posted September 19, 2011 Share Posted September 19, 2011 I will go over each item when I have more time, but the 944-spec rules have be developed over nearly 10 years of use. Some of things you suggest have been allowed due to not finding a need. Some due to marginal cost. $200 here and there can turn into big money. I have been with these cars since the start and worked with the rules. So each issue has been explored. I will share the history. Quote Link to comment Share on other sites More sharing options...
944-Spec#94 Posted September 19, 2011 Share Posted September 19, 2011 Anyway that said, I have a few questions about rules. Crankshaft The rules allow an additional rod hole for oiling. One of the successful modification that we had made with the extra cross hole was to enlarge the oil feed hole between the rod and main bearing, then tap where the plug was and install a threaded plug instead of crimped one. We found that the extra hole does not do much good without the larger feed hole to feed it. Is that permitted. That has never been brought up as mod. I have not been aware of it. Seems like a reasonable idea. Our 2012 rules change proposals period will be opening up soon so this can be a proposal. However we need some numbers. Enlarge hole? How much? The reason is should we ever do tear down to a crank we need some numbers to validate the mod is to the rules so dimensions are important. In general we allow things that may help oil flow to the bearings. This a know issue so even if these mods cost money they will all come to save money if they prevent a spun bearing. Most have zero performance impact as well. Engine and Transmission mounts Did I miss it, or can we not run solid engine and transmission mounts. If not, why. They are not very expensive and create one less thing that can fail. No solid mounts. The stock ones work fine. Now granted alot of original mounts are toast, but replace them once and you never need to think about them again. So in this case solid mounts add cost and potential will put more power to the ground. So that is why we have never allowed them from day 1. IAC Motors I have never run an idle air control motor. Is an IAC part of the 'emission system' that can be removed ? IAC Motor? Huh? We have motors for that? There is an idle stabilzer valve (ISV) under the intake manifold that is used on cars with 85.5 to 88 fuel injection. This not an emissions control device, but an idle speed control device. The 83-85 cars use an auxailly air valve to also perform idle control. I suggest one of the two devices remains in the car as the rules do not allow removal of this and these are not emissions devices. The early cars do use a second idle control device for A/C. This is located behind the air box and because it serves to only increase idle when the A/C is on it can be removed. That is part of the A/C system. The later cars moved that functionallity in to the ISV so the ISV does both. 17mm vs 19mm ball joints This is just a question. Why can we not use the larger 19mm when rebuilding if they are stock height. Yes, they add cost over just finding some more stock arms in good shape, but they offer no performance advantage, so why not allow them for people who want to spend a little extra to have stronger ball joints. (this coming from a guy who snapped a 19mm one this year) We have never found the need to move the the 19mm pin. I think the big reason is that we can only run a 225 toyo RA-1. This tire is not as sticky as fat hoosier so puts less load on the ball joints pins. Short shift trans linkage Why can't we add these. They are cheap and easy to install. Cost and potential performance advantage by being able to shift faster. This has been discussed in the past and we chose to keep it stock. The only reason any one would run a short shifter is to make the car faster. So given than we said no. Keep it stock. Remember if mod does nothing, but make car faster it tend to not be allowed. We have cars fast enough to fun to drive and spending $250 for an extra .2 on the track is not a good value. All it will do is force every one to spend $250 to compete Lexan hatches I am in the 'do not change the rules' club. I have had both and I am thrilled to be going to a class that does not use them. They are flimsy at best and a pain in the butt. I am constantly waiting for mine to pop out and blow away on track even though I have straps running the length of the hatch. I would rather see permission to run fiberglass hoods (20lbs savings) instead of lexan hatchs. Fiberglass hood is actually a better place to save weight because the cars once stripped out get a little nose heavy. However again why would anyone do this mod other than to make the car faster? So that will in effect force it on most guys adding cost and not making the racing any better. That is why we say no. Springs and torsion bars What is some of the best combinations that are being used here. (primarily the torsion bars) I do not mind changing front springs, but would really like to start out with the right size torsion bars. Most guys run 30 mm t-bars. I once ran 28 mm t-bars in my car. I found they matched up well with 250lbs springs. However when I changed to 350lbs springs they rear was way too soft. I could compensate, but it was band-aid. So I changed to 30 mm t-bars back in 2003 and have never looked back. Front spring rates range from 250-400 for most guys. I would say we a 90% 30 mm bars. Do some searching and you will see different set-ups. My thinking is that if you are coming from a stiff car go with 30 mm t-bars and 350 or 400 lbs springs and then use weltmeister sway bars front and rear. These bars give you a nice adjustment range. I think the difference betwen 350 and 400 lbs in the front is a toss up. If you go past 400 you start running into issues of over powering the Koni shocks we use. They can handle may be 450lbs, but 500lbs is just too much. Plus it does not work well with 30 mm bars. BTW... these "soft" spring rates are a key to out cost containment. The softer springs allow us to use street performance shock rather than a more expenisve racing shock. The cars are still stiff enough to respond, but compliant enough to keep costs down and the chassis manageble for new racers. 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loftygoals Posted September 24, 2011 Share Posted September 24, 2011 IAC Motor? Huh? We have motors for that? There is an idle stabilzer valve (ISV) under the intake manifold that is used on cars with 85.5 to 88 fuel injection. This not an emissions control device, but an idle speed control device. The 83-85 cars use an auxailly air valve to also perform idle control. I suggest one of the two devices remains in the car as the rules do not allow removal of this and these are not emissions devices. The early cars do use a second idle control device for A/C. This is located behind the air box and because it serves to only increase idle when the A/C is on it can be removed. That is part of the A/C system. The later cars moved that functionallity in to the ISV so the ISV does both. Wait a second...I've seen very few 944 Spec cars with the full idle/vacuum system intact. It is common to remove the idle control devices and the venturi. With all the swapping of late to early harnesses and DMEs, the ISV doesn't work half the time anyway. I just looked at the rules, and I this it is a gray area. I feel it should be specifically allowed since many spec cars are with out these parts, removing them doesn't cost anything, it doesn't increase performance, and help create reliability by removing the potential for vacuum leaks. -bj Quote Link to comment Share on other sites More sharing options...
Sterling Doc Posted September 25, 2011 Share Posted September 25, 2011 Some good points brought up here. We'll need to address these in the 2012 rules revisions. Quote Link to comment Share on other sites More sharing options...
Members Al F. Posted October 10, 2011 Members Share Posted October 10, 2011 I agree with BJ wholeheartedly. There is no reason to insist on this stuff being there. Its zero cost to remove and can only help reliability. Ed...welcome aboard 944Spec!!! I watched you at nationals quite a bit. I love the paint scheme on that car Quote Link to comment Share on other sites More sharing options...
Zach H. Posted October 24, 2011 Share Posted October 24, 2011 You guys should also look into using a non paper head gasket. its not a performance advantage and it will only prolong the life of your engine. Quote Link to comment Share on other sites More sharing options...
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