cmc35 Posted August 6, 2008 Share Posted August 6, 2008 I made the leap to 17s and haven't felt much difference, except in unsprung weight. The 17" package I use (275/40 shaved to 4/32s on a Camaro SS 10 spokes) is 4-5 lbs heavier per corner than the 16s (255/50 shaved to 4/32s on a 98+ Firebird 5 spoke) If you stack 4 255 16s next to 4 275 17s, the height difference is less than 1" Great info, Mitch, thank you. -chris Quote Link to comment Share on other sites More sharing options...
ShadowBolt Posted August 6, 2008 Share Posted August 6, 2008 I made the leap to 17s and haven't felt much difference, except in unsprung weight. The 17" package I use (275/40 shaved to 4/32s on a Camaro SS 10 spokes) is 4-5 lbs heavier per corner than the 16s (255/50 shaved to 4/32s on a 98+ Firebird 5 spoke) If you stack 4 255 16s next to 4 275 17s, the height difference is less than 1" I don't see the extra 1" of tire width (total) being worth an extra 20lbs. of unsprung weight? Think I will stay with my Cobra brakes and 16" wheels. JJ Quote Link to comment Share on other sites More sharing options...
King Matt1548534716 Posted August 6, 2008 Share Posted August 6, 2008 To me, the only reasons to go to the larger wheel are the possibility of fitting 13-inch brakes and general wheel availability. But with the new brakes rules coming, I don't think even that would be necessary given the stopping ability that can be generated with the 12-inch four-piston setups. There is really not much if any difference in available lateral grip between the 255 we use and the AI 275 from the data I've seen comparing my old Fox to an AI Fox. Quote Link to comment Share on other sites More sharing options...
Tony G Posted August 6, 2008 Author Share Posted August 6, 2008 You guys are 100% correct, no need to jump to 17's at all. So do you need bigger brakes and bigger tires..not really,it's all a personal choice. As with all the rules just because there is a certain rule or change of a rule, that does not mean you have to change to that rule if there is an existing one you can still follow. Both a CMC National Champion and a West Coast regional champion won with stock brakes..no upgrades I'm talking 10" rotors stock single piston calipers,one was a Camaro,one was a Mustang...and oh yeah they beat all the big brake cars they were racing against. Tony Guaglione Quote Link to comment Share on other sites More sharing options...
j dawes Posted August 7, 2008 Share Posted August 7, 2008 Maybe this was answered elsewhere, but I remember it being an issue that Toyo may not be making the 16 inch R888 in the 255/50 series...is this true or yet to be determined or ??? Quote Link to comment Share on other sites More sharing options...
Alien Posted August 7, 2008 Share Posted August 7, 2008 They will be produced. CMC (I hope) would choose another spec tire rather than force it's drivers to go up to 17's. Quote Link to comment Share on other sites More sharing options...
Tony G Posted August 7, 2008 Author Share Posted August 7, 2008 I just bought 10 16" R888's. So yes they are here to stay. Tony Guaglione Quote Link to comment Share on other sites More sharing options...
BADVENM Posted August 27, 2008 Share Posted August 27, 2008 Any updates on where we are headed for 2010? Quote Link to comment Share on other sites More sharing options...
ST#97 Posted August 28, 2008 Share Posted August 28, 2008 331/347 combos on E7 or GT40 iron heads is a waste of money... you can easily hit the 260/300 numbers on GT40's and an e-cam with 302 cubes...maybe some rockers to get flow moving. 347's aren't all that great when it comes to piston wall wear either... Definitely don't want to stir the pot, but making assumption without documented proof can lead someone to actually believe that statement above in bold. Seen it done on 5.0's for quite a while now...maybe even 320 tq. Jerry, mustangs get spanked at TWS because of aerodynamics...unless they let you put an f-body nose on your car, not much else can be done...just a pro/con of the platform. Quote Link to comment Share on other sites More sharing options...
j dawes Posted August 28, 2008 Share Posted August 28, 2008 (edited) I have a 1995 Cobra motor in my CMC car. It does NOT make 260/300. Not even close. What do you suggest? Edited August 31, 2008 by Guest Quote Link to comment Share on other sites More sharing options...
cmc79 Posted August 28, 2008 Share Posted August 28, 2008 You have an e-cam in a CMC legal Mustang? Quote Link to comment Share on other sites More sharing options...
ST#97 Posted August 28, 2008 Share Posted August 28, 2008 I have a 1995 Cobra motor in my CMC car. It has that stuff on it. It does NOT make 260/300. Not even close. What do you suggest? Well, a list of questions first.... 1. How old is the motor 2. Leak down and compression test? 3. what is the timing at? 4. Fuel pressure? 5. Valve train age...weak springs? 6. Are they GT40's? 7. What's the Compression ratio? 8. Ignition parts current? 9. Which computer are you running? Suggest 93 down and requires some work? Legality? 10. shortbelt or u/d's...? 11. Were the heads rebuilt and intake ports/valves cleaned? 12. What air intake are you using...? Is it pulling cool air. 13. Are the O2's reading correctly? 14. What is the a/f ratio...? 15. How far from the numbers are you? drastically tells me the motor is probably tired...? 16. e-cammed Legal CMC? sorry, had to ask....again! So many factors to know but an ecammed cobra motor should/could get into the 270's and 280's on the HP side...300-310 on the tq....maybe 290's if you lean it out to kill power. Quote Link to comment Share on other sites More sharing options...
K Shaw Posted August 29, 2008 Share Posted August 29, 2008 I have a 1995 Cobra motor in my CMC car. It has that stuff on it. It does NOT make 260/300. Not even close. What do you suggest? Where are the #s right now? Our fresh 302 made 230/300 with E7 heads and a cobra intake. Cobra cam or HO cam? Where is the timing and fuel pressure? Cobra intake or stock? The stock intake is a poop box and flows less than the fox mustang intakes do to a different design to clear the lower hood on the sn95. Chris M made the # with GT40 heads and stock intake on his 95. kyle Quote Link to comment Share on other sites More sharing options...
Tri-Agan Posted August 30, 2008 Share Posted August 30, 2008 16. e-cammed Legal CMC? sorry, had to ask....again! He is joining in February when he gets his comp license, and he is trying to make a point. Cut him some slack. The E cam very well may be written into the rules by then. We'll see. I personally think he makes a valid point, and I think it's important to see where some of these HPDE cars are with their mods, and the HP/TQ results, before we make hard changes. Kent Quote Link to comment Share on other sites More sharing options...
ST#97 Posted August 30, 2008 Share Posted August 30, 2008 16. e-cammed Legal CMC? sorry, had to ask....again! He is joining in February when he gets his comp license, and he is trying to make a point. Cut him some slack. The E cam very well may be written into the rules by then. We'll see. I personally think he makes a valid point, and I think it's important to see where some of these HPDE cars are with their mods, and the HP/TQ results, before we make hard changes. Kent From what I understand the E-xperiment is already under way and inked into the 2010 rule... no sweat... Quote Link to comment Share on other sites More sharing options...
j dawes Posted August 31, 2008 Share Posted August 31, 2008 (edited) I made a mis-statement. For some reason, I was under the impression that the E-cam was the STOCK Cobra cam. I was WRONG! I apologize for that. The motor is a primarily bone stock 95 Cobra 5.0. I think the only thing changed on it is that the thermactor tube is welded shut and the egr may be disabled. It has ~145k miles on it and I have not done any testing on it [compression, leak down, etc.]. I've got the stock airbox. It may have UDPs, but I know it has a short belt and the smog pump & A/C are removed. The last dyno sheet I have says iirc 225/275 and that was sometime in the 2006 season [sorry, it's not in front of me at the moment]. [i also know that Steve Poe took 7th at nationals in 2007 with this motor before he sold it to me, fwiw...he's obviously a much more experienced driver than I am.] I know there are some 'magic formulas' [which cam/heads, which intake, airbox, etc.] out there, and have spoken with some CMC car owners that make 2010 power using a 5.0. My question basically stems from my potential misimpression that a Cobra motor would make more power than I'm currently making...I'm learning this stuff as I go so thanks for the patience [and support, Kent, Dan, etc.]. Edited September 1, 2008 by Guest Quote Link to comment Share on other sites More sharing options...
ddteman1548534717 Posted September 1, 2008 Share Posted September 1, 2008 Well, I'll be the one to start it. I would question any one who is making 260hp and 320 ftlbs at the rear wheels with a stock 5.0 cobra or not. " Stock Cam, Compression, no head port work, computer tuning. ETC" There I said it. Now someone one tell me I'm wrong. Quote Link to comment Share on other sites More sharing options...
ST#97 Posted September 1, 2008 Share Posted September 1, 2008 Well, I'll be the one to start it. I would question any one who is making 260hp and 320 ftlbs at the rear wheels with a stock 5.0 cobra or not. " Stock Cam, Compression, no head port work, computer tuning. ETC" There I said it. Now someone one tell me I'm wrong. We aren't talking stock... we are talking GT40(p) heads, shorties, e-cam, timing and fuel pressure adjustments and maybe u/d pullies... should be right on those numbers! Quote Link to comment Share on other sites More sharing options...
K Shaw Posted September 1, 2008 Share Posted September 1, 2008 Who said 260 hp? I am talking about what combos are making the current #s. If we can make the current #s with out all of the Cobra parts and I dont understand why one couldnt make the new #s with the rest of the cobra parts and headers etc. kyle Quote Link to comment Share on other sites More sharing options...
MHISSTC Posted September 18, 2008 Share Posted September 18, 2008 It's been a few weeks. How about another one of those I will update this subject quite often updates. I've got an engine ready to be built right now that I had initially planned on running as a carbed spec engine. I need to know for sure if the current spec engine intake and carb are going to remain legal (and not obsolete and forced to run EFI) in 2010 and which variety of GT40 heads (Explorer?) are going to be legal since it appears my planned E7 heads are doomed to obsolescence with the proposed 2010 power bump. I don't want to build a single year legal engine. How about a definite decision on long tube headers? Inquiring minds (and engine builders) want to know. Quote Link to comment Share on other sites More sharing options...
cmc35 Posted September 18, 2008 Share Posted September 18, 2008 Decisions about parts, e.g. long tubes, will be made AFTER tests are completed. We realize folks want answers right now, but we are doing our best to get data first. -chris Quote Link to comment Share on other sites More sharing options...
Glenn Posted September 18, 2008 Share Posted September 18, 2008 to be honest w/ you, the power limit does not need to be met in order to run up front. i'm a perfect example. i took first at the Nationals w/ 210-212 rwhp, and 280-286 rwtq. i was 20hp/20tq from the limit. if you are a new novice driver, dont worry about max power as seat time is way more important. build the motor and get on track. run for a couple years and then when your 100% sure its the lack of power holding you back from a podium, start the upgrades. if you just have to wait, then you will have to wait. people are still testing set-ups and it will be post 2008 season before we know anything. but lets say we post what we think will be the set-up for 2010 today w/ testing to back it up. then once we have the first race the Fox cars walk off and leave the rest of the field. at that point its likely an adjustment will be made. so what i'm trying to say is be ready to be required to make changes to your set-up to remain legal. if your looking to not make any changes at all once you get the motor together....... wait till 2010 to get an idea if that will happen. Quote Link to comment Share on other sites More sharing options...
roadracerwhite Posted September 18, 2008 Share Posted September 18, 2008 I would agree with Glenn. This years nationals proved quite a bit, all of us within a second and a half lap times, and presumably different dyno numbers from the top guys. I would also say that I don't believe long tubes are within the scope of CMC. It has been proven that a good set of ($2500) long tubes will make a ton of torque. We can argue that we have to be dynoed anyway, but I don't think we want to go there. Just my opinion. Bryan Quote Link to comment Share on other sites More sharing options...
MHISSTC Posted September 18, 2008 Share Posted September 18, 2008 Thank you Chris, Bryan, and Glenn for the responses. The information gleaned from the 2008 Nationals has provided us all with some useful insight. Congratulations to all of you. I'm interested in finding out from our CMC leadership if any progress has been made in refining the proposed 2010 rules. I listed specific items about which my engine builder has been asking me. He is as anxious as I am to proceed with my engine build. However, that build is at a standstill until I can provide him with additional information as to what parts are going to be legal or not. (I do know that I can definitely tell him ported E7 heads are out ) While I understand it is not a requirement to build an engine to the maximum numbers allowed by the rules, I have the opportunity to attempt it right now. I would like to take advantage of that opportunity, want to remain legal in doing so, and do not want to duplicate the efforts or expenses made now in 2009. Scott Quote Link to comment Share on other sites More sharing options...
cozog1548534733 Posted September 18, 2008 Share Posted September 18, 2008 Why not let him be one of the guinea pigs for testing engine components? Quote Link to comment Share on other sites More sharing options...
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