Carson Posted January 15, 2009 Share Posted January 15, 2009 does anybody have real dyno test numbers under the new CMC2 engine rules for the 3rd gen GMC cars ? either 5 lt or 5.7 lt .... carb or TPI ????? Quote Link to comment Share on other sites More sharing options...
cmc38camaro Posted January 20, 2009 Share Posted January 20, 2009 All It would be great to see some responses to Carson's question. As you are aware we have 4 engine packages available for these cars. Dyno results will show if the rules are correct or may point out some needed changes. I know of one 305 TPI car that has installed roller rockers without headers and the dyno results show more of a horsepower gain than I anticipated. Data is our friend so please post your dyno results. Thanks, Mike Quote Link to comment Share on other sites More sharing options...
camaro_1le Posted January 20, 2009 Share Posted January 20, 2009 All It would be great to see some responses to Carson's question. As you are aware we have 4 engine packages available for these cars. Dyno results will show if the rules are correct or may point out some needed changes. I know of one 305 TPI car that has installed roller rockers without headers and the dyno results show more of a horsepower gain than I anticipated. Data is our friend so please post your dyno results. Thanks, Mike Based upon preliminary results, I personally believe that the GM 5.0 TPI should in be in CMC2 Chart #2. Currently, it is lumped together with the 5.7 TPI in chart #3. No way the 5.0 TPI can make chart 3 numbers with the allowed modifications. But it can make chart #2 numbers with those modifications. As long as the 5.0 TPI is in chart #3, I think anyone would be foolish to attempt to build one. Quote Link to comment Share on other sites More sharing options...
Tri-Agan Posted January 21, 2009 Share Posted January 21, 2009 Based upon preliminary results, I personally believe that the GM 5.0 TPI should in be in CMC2 Chart #2. . Jim......explain the results in greater detail. Kent Quote Link to comment Share on other sites More sharing options...
camaro_1le Posted January 21, 2009 Share Posted January 21, 2009 Based upon preliminary results, I personally believe that the GM 5.0 TPI should in be in CMC2 Chart #2. . Jim......explain the results in greater detail. Kent Long story, short. With the addition of the 1.6 aluminum roller tip rockers, my dyno numbers were 247/317 on three consecutive pulls. The motor had put down 232/305 peak last January. The directors know the history of the motor and what has been done to it. It is legal in every way. Many of you left coasters know the dyno man...Jeff Creech. The thought is, if I add a set of shorty headers I should be right there at the Chart #2 numbers. Based upon my dyno results, the only way for me to get to chart 3 is bore the motor for more displacement or to trah the 305 for a 350. Now I am in a pickle with 30 days to go. I have requested the 305 TPI to be put into Chart #2 via my regional director. Otherwise, I will simply pull the rockers and replace them with the 1.5 steel and stay in CMC. I really do not feel like spending the money on headers and probably a new y-pipe at this point. And heading back to the dyno.....although Jeff is the best guy to work with in the world. Quite frankly, I was shocked by the numbers. I truly did not believe the simple mods could put a third gen 305TPI into CMC2. I guess I should of read the power charts more carefully before I decided to experiment. Quote Link to comment Share on other sites More sharing options...
Glenn Posted January 21, 2009 Share Posted January 21, 2009 i think you have a good case for what your asking, but you will need to add the headers to prove it. the flip side its good to see your getting close w/ minimal work, one step closer forthe 3rd gens. now for wheels and brakes. Quote Link to comment Share on other sites More sharing options...
camaro_1le Posted January 21, 2009 Share Posted January 21, 2009 i think you have a good case for what your asking, but you will need to add the headers to prove it. I think I need to hear the justification and empirical evidence for putting the 5.0 TPI and the 5.7 TPI into the same power chart. The error rest there. There is enough reasonable doubt that is was a bad decision. The way it stands now, I have little choice to go back to the 1.5 rockers and remain in CMC. I have already made decent CMC numbers. On a personal note, I am running a TrueTrac diff and need to upgrade it. So the money for headers, y-pipe and testing will be direct to a Detroit Locker today. Quote Link to comment Share on other sites More sharing options...
Glenn Posted January 21, 2009 Share Posted January 21, 2009 fair enough. but realize that what little you did goes a long ways to helping resolve the issue w/ the 3rd gens. it will just take time. Quote Link to comment Share on other sites More sharing options...
camaro_1le Posted January 21, 2009 Share Posted January 21, 2009 fair enough. but realize that what little you did goes a long ways to helping resolve the issue w/ the 3rd gens. it will just take time. What little I did? I believe you were privy to the discussions that have taken place over the past week of what has gone into this motor. I have about $5000 into this motor right now. I had it run the first half of the 2009 season and then the second half spent chasing why it was dropping a cylinder over 180 degrees engine temp. So don't give me that, what little I did. What have you done? Right now, I believe I have a decent CMC motor to start 2010. I don't feel like dumping another $1000 into headers, y-pipe and tuning to disprove an error. I figure I can recoup some of the expense by selling or even returning the rocker arms. I have the data to back up the claims for the rocker arms, so it should be easy to sell them You wanted some data, I gave you some data. What data backs up the assertion that the 5.0 TPI should be lumped in with the 5.7 TPI? I have provided enough data to cast reasonable doubt. Quote Link to comment Share on other sites More sharing options...
Tri-Agan Posted January 21, 2009 Share Posted January 21, 2009 Jim, Glenn didn't see the numbers yet. I sent them to Mike so that he could look into the disparity between the 5.0 TPI and the 5.7 TPI and see what he thought we should do. I absolutely agree that it doesn't make sense for you to add the headers before the combination is approved for table #2. (I think you should stay in CMC since I am going to CMC2.) I really don't want any added competition, so don't expect any help getting table 2 approved for your 3rd gen. Kent Quote Link to comment Share on other sites More sharing options...
mitchntx1548534714 Posted January 21, 2009 Share Posted January 21, 2009 Quote Link to comment Share on other sites More sharing options...
Adam Ginsberg Posted January 21, 2009 Share Posted January 21, 2009 I have about $5000 into this motor right now. $5000?!?!?!?! Damn. I don't know many folks that have that kind of coinage in their CMC lump.....ouch. I had it run the first half of the 2009 season and then the second half spent chasing why it was dropping a cylinder over 180 degrees engine temp. Out of curiosity, did you figure out the problem? Quote Link to comment Share on other sites More sharing options...
Glenn Posted January 21, 2009 Share Posted January 21, 2009 (edited) fair enough. but realize that what little you did goes a long ways to helping resolve the issue w/ the 3rd gens. it will just take time. What little I did? I believe you were privy to the discussions that have taken place over the past week of what has gone into this motor. I have about $5000 into this motor right now. I had it run the first half of the 2009 season and then the second half spent chasing why it was dropping a cylinder over 180 degrees engine temp. So don't give me that, what little I did. What have you done? Right now, I believe I have a decent CMC motor to start 2010. I don't feel like dumping another $1000 into headers, y-pipe and tuning to disprove an error. I figure I can recoup some of the expense by selling or even returning the rocker arms. I have the data to back up the claims for the rocker arms, so it should be easy to sell them You wanted some data, I gave you some data. What data backs up the assertion that the 5.0 TPI should be lumped in with the 5.7 TPI? I have provided enough data to cast reasonable doubt. what the fuck is your problem! all i know is you put on a set of 1.6 ratio rockers and saw good results from it. i thanked you for that effort. so as much as there seems to be a back story here i didnt know of on your end, i promise you there is a back story on the director end you know nothing about. so dont ask what i have done, i have done alot too. since the Directors were REQUIRED to set the rules in stone and make adjustments as we go, we did the best we could. w/ what little to no data we had. you come forward w/ this, and we will now make an adjustment. Edited January 21, 2009 by Guest Quote Link to comment Share on other sites More sharing options...
Glenn Posted January 21, 2009 Share Posted January 21, 2009 i've got $1700 and it has all the bells and whistles. Quote Link to comment Share on other sites More sharing options...
Adam Ginsberg Posted January 21, 2009 Share Posted January 21, 2009 Ease up, Glenn. Maybe he just needed a cup of coffee. FWIW, I'm really surprised that a set of 1.6 RR's provided that kind of HP increase. Was the motor fully rebuilt prior to the addition of the RR's, or were just the rockers added?? Quote Link to comment Share on other sites More sharing options...
Members Al F. Posted January 21, 2009 Members Share Posted January 21, 2009 Glenn, Jim...take it easy and play nice I will be absolutely psyched if we can prove that a 305TPI with rockers and with/without headers can make good numbers for table 2. As it is, we did the best with what we had. I think Mike did a fantastic job researching and modeling on the computer...all indications were torque would go up much faster than hp, hence the creation of table 3. Proving table 2 will work for these motors will be fantastic since it will be easier to maintain parity between the platforms. Jim...thanks for the efforts and the info. Remember, it isnt that we dont want those cars there, its that we didnt think they'd be able to get those numbers with reasonable mods. Its looking like maybe they can. Hopefully others will soon follow and see similar results. Quote Link to comment Share on other sites More sharing options...
Dave Schotz Posted January 21, 2009 Share Posted January 21, 2009 I haven't gotten to see any dyno numbers yet for the TPI cars.. .since my 225/290 305 TPI CMC car... I'm currently doing the CMC2 w/ a 350 TPI Transplant... and just haven't gotten it completed... so busy... unfortunately. My goal... was possibly if your car ends up on Table 3 or Table 2... you could pick... I'm just afraid dropping in a 350 will get me closer to 260 HP... 320 TQ... than 240HP... 340 TQ... So... this way... hey... whichever we land on... go crazy.... But I definitely don't have any experience w/ the 350 TPI Stock Dyno Numbers... hopefully I will shortly... I am afraid... if CMC2 doesn't get straightened out quickly... we will find ourselves with another CMC ONLY at the Nationals... which isn't fun for anyone. Quote Link to comment Share on other sites More sharing options...
Rustang72 Posted January 21, 2009 Share Posted January 21, 2009 I have about $5000 into this motor right now. $5000?!?!?!?! Damn. I don't know many folks that have that kind of coinage in their CMC lump.....ouch. $5000 motors aren't unusual around here. Please make the rule change for Jim... I want to see him on the 17" wheels he opposes so much for CMC. As a bonus we can continue to watch the purple dinosaur stalk Kent. Quote Link to comment Share on other sites More sharing options...
camaro_1le Posted January 21, 2009 Share Posted January 21, 2009 I am in an all day meeting, so please excuse me for not responding until a little later in the day. Quote Link to comment Share on other sites More sharing options...
cmc38camaro Posted January 21, 2009 Share Posted January 21, 2009 Long story, short. With the addition of the 1.6 aluminum roller tip rockers, my dyno numbers were 247/317 on three consecutive pulls. The motor had put down 232/305 peak last January. The directors know the history of the motor and what has been done to it. It is legal in every way. Many of you left coasters know the dyno man...Jeff Creech. The thought is, if I add a set of shorty headers I should be right there at the Chart #2 numbers. Based upon my dyno results, the only way for me to get to chart 3 is bore the motor for more displacement or to trah the 305 for a 350. snip One of the problems here is that the modifications are half done. The impact of shorty headers is missing. It is premature to declare that the 305 TPI will fit in table 2 and even more premature to be asking for the rules to change. I would suggest it will take at least 2 dyno results from 305 TPI engines with both 1.6 roller and shorty headers producing similar results before we start talking about rules changes. Jim's dyno numbers above show that he is at the top end of allowable torque for table 2. Stating that table 2 works requires the assumption that the addition of shorty headers will add horsepower without adding torque. My experience on my daily driver TPI car is that headers add both. DynoSim shows gains to both horsepower and torque as well. We need facts here, SW modeling is not good enough, neither is a half done experiment. Is anyone else out there in the process of modifying their 305 TPI car to CMC2 specs? Jim is in a pickle, he can move back to CMC or go forward to CMC2. The latter may require some form of rules exception and/or rules update and the directors have that authority. It sure would of been nice to use 2009 as a test year to wring out these kind of issues. Now some questions for the LT1 guys: When you restrict down your LT1, what is the relationship between horsepower and torque? Do they decline evenly or do they decline on their own curve? Mike Quote Link to comment Share on other sites More sharing options...
Rustang72 Posted January 21, 2009 Share Posted January 21, 2009 I would suggest it will take at least 2 dyno results from 305 TPI engines with both 1.6 roller and shorty headers producing similar results before we start talking about rules changes.Allowing 3rd gens into CMC2 is a rules change done without dyno results. (or so it would seem from reading this thread)Jim is asking for a correction to that based on real dyno results. Why does changing a rule require no results, but correcting that rule require multiple results? Oh yeah, "it is what it is". Nevermind. Quote Link to comment Share on other sites More sharing options...
mitchntx1548534714 Posted January 21, 2009 Share Posted January 21, 2009 Now some questions for the LT1 guys: When you restrict down your LT1, what is the relationship between horsepower and torque? Do they decline evenly or do they decline on their own curve? Mike The 3 I have had access to when making unrestricted vs restricted pulls has shown seperate curves. But I do believe there are some caveats to take into account. If you bring a PCM that has been in a restricted car for a period of time, the ECM has "calibrated" fuel delivery and spark to obtain max effiency as read by the O2 sensors, among others. Yank the plate and make a pull and you might see some skewed, yet perfectly legal numbers, simply because the ECM hasn't "learned" the new delivery and altered the calibration based upon the change in the air charge. So, "in theory", I could take my LT1 to a local TNT day and run unrestricted to let the ECM learn. Then, install a restrictor plate, go to the dyno and get a dyno number from an extremely fat fuel table. Print it out and turn it in for the 2009 CMC points race. After a couple on track sessions, the ECM will learn the new air charge and lean out the fuel. I wonder what leaning out the fuel mixture would do to the HP/TQ curve? In reality, I don't think the change is a lot, but there will be a change. Quote Link to comment Share on other sites More sharing options...
Glenn Posted January 21, 2009 Share Posted January 21, 2009 mitch is correct w/ regards to separate curves. a restrictor will affect HP more than TQ. but lets look at the reason why that is so on an LT1 so we dont assume its so w/ the TPI. an LT1 restricted to CMC numbers makes peak TQ at 2K-2.5K. at those RPM's the resrtictor plays almost no role. but in the upper RPM's where HP is starting to be made, the plate kills the HP and does not let the TQ grow. peak TQ on an unrestricted LT1 is around 3.8K. thats almost a 2K shift for a 20 ftlb gain. but HP jumps from below 230 to well over 270 (in my case). w/ 260's being the norm. will this be the case when we mod the TPI? who knows, and thats why we need people who have done ANYTHING to post up results. Quote Link to comment Share on other sites More sharing options...
Carson Posted January 21, 2009 Author Share Posted January 21, 2009 let's keep this thread on subject and start another thread on the LT1 subject 92_1LE research gained 15 hp + 12 tq w/ 1.6 roller tips THAT'S WHAT I NEED TO GET TO THE 230-300 MAX CMC NUMBERS with my stock 305 TPI so why not allow it for those that need it ? Quote Link to comment Share on other sites More sharing options...
camaro_1le Posted January 21, 2009 Share Posted January 21, 2009 First a correction, the numbers with the addition of the rocker arms are 248/314. The directors have the dyno sheet. Right now the car is back to 231/299 and will stay there for 2009. Quote Link to comment Share on other sites More sharing options...
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