Alien Posted January 20, 2011 Share Posted January 20, 2011 You can't possibly be suggesting there is a significant difference in torque output--that would throw the concept of engine parity out on its ear. Actually, it was my personal feeling of some peoples idea that a T5 will blow up upon installation behind a LT1. On TGO (Thirdgen.org), it is a common reply when someone asks to swap out a 350 for their 305/5 spd. OMG it's going to grenade into billions of bits! Why GM didn't do it from the factory? Probably because it was marinal at best, and being a company that has to try please everyone, margins of safetly, warranty etc, they chose not to offer the T5 behind the 350s. What I never hear about, is when someone upgrades their 305 with a cam, headers, tune etc, is a cry for swapping out the weak T5. Comparing the numbers, is a 260/310 engine THAT much more likely to blow up a T5 than a 230/300 engine? That 10ft*lbs is what puts the T5 over the edge? My gut feeling is that it is a lot of luck of the draw. Some T5's are built well, some were built at 4pm on a Friday. I think if a T5 blows up behind a 350, it probably would have blown up behind a 305. FWIW, I autocrossed a mild 350 with nonWC T5. I've roadraced a worn out WC T5 behind the 305 for 3 years now. Just rebuilt it with the better bearing plate this year as a preemptive strike. Maybe I'm just lucky. *edit * As a data point, two T5's I've seen blow behind a third gen 305 were due to age and axle hop, so I don't think the tq arm connected to the trans helps. One of those two was already grinding upon installin, feel that was a ticking bomb already. Now, to answer the original question, is there a better alternative? Sure. T56 or tremec. Is it 100% necessary? I think no. Quote Link to comment Share on other sites More sharing options...
KiMifan Posted January 20, 2011 Share Posted January 20, 2011 That all makes sense to me. Wheel hop is definitely bad for any transmission, especially in a car with sticky tires. The ratcheting action this imarts to the gears can cause the teeth to chip or crack, and the harder the gear suraface, the more likely it is to occur, which is why some builders of road race transmissions recommend drawing down the hardness by annealing the gears. There may be more margin for abuse in a TKO or T56, but if wheelhop is a recurring problem, you will eventually damage any transmission, so better to try resolve the underlying cause than hope that throwing more mass at the problem will make it go away. Quote Link to comment Share on other sites More sharing options...
jeffburch Posted January 22, 2011 Share Posted January 22, 2011 Depending on the track, a racing car spends a majority of time in 3rd gear. Or going to/from 3rd gear. In a T5, 3rd gear is near center of the one piece cluster shaft. The bearing surfaces are farthest away on the ends of the shaft. Whether it's shaft deflection or case deflection this cluster is gonna give up. I wouldn't recommended any new build around a T5. jb Quote Link to comment Share on other sites More sharing options...
TxCMC22 Posted January 22, 2011 Share Posted January 22, 2011 A stock T-5 is not a great transmission, although the platform is amazing! The aftermarket support for them is at the top of the list. Just because it says T-5 on the case doesn't mean much these days... Run what you want, but I will stick with a T-5 behind my Mod Motor all day long! With a spare in the truck... At least I don't have to pull the motor to get the transmission out... Quote Link to comment Share on other sites More sharing options...
APatelIroc Posted March 7, 2011 Author Share Posted March 7, 2011 so after further searching and thought it looks like i'll have a buy a thirdgen with an LT1 swap already done which i really dont want to get into because who knows what someone did to sire the thing up... could be hacked to hell and i dont need to deal with that. other is to buy a thirdgen and have a swap done at a shop like Hawks or somewhere. Then i started thinking why not use a LT1 4th gen to begin with? I've always liked thirdgens better for looks and for how easy they are to work on.. i have the fact that 4th gens have half (or nearly half) the motor under the windshield/dash. What do you guys things about going this path? There are a lot of 4th gens for sale with near 100k miles that i could get for cheap and use for HPDE while i start to build for CMC2. What are your guys thoughts on 3rd gens vs 4th gens for CMC2? I already have two 3rd gens so its not like i am desperate to have my first or just have one in general. Quote Link to comment Share on other sites More sharing options...
85t5mcss Posted March 8, 2011 Share Posted March 8, 2011 My opinion counts for nothing since I've not been on track, YET. But looks wise and ease I prefer 3rd gens. Both have pros/cons. But since I am diehard GM 80s fan, its an easy call for me. Quote Link to comment Share on other sites More sharing options...
APatelIroc Posted March 8, 2011 Author Share Posted March 8, 2011 It's such a hard choice. I am in love with thirdgens but want to have an lt1/t-56. I just spent 3 yrs building my current 92z and have no interest going into another swap so I have to try and find a thirdgen with a properly done lt1 swap for a good price. I am finding a lot of '95 z28s that are great buys that can get me into HPDE for a year or two while I build to cmc2 spec. Or I'll have to wait to try and get a thirteen roller with no rust then send it to a shop that'll do a complete swap for cheap. Hawks was giving me 5500-6500 for a thirdgen with lt1 swap but not sure the condition of the car. Could be a rust bucket or some salvage car that I don't want to get into. This is gonna be one of those things that I just choose a path and live with it. Quote Link to comment Share on other sites More sharing options...
cozog1548534733 Posted March 8, 2011 Share Posted March 8, 2011 This is gonna be one of those things that I just choose a path and live with it. Since CMC is moving to 260HP/300TQ in 2012, you'll have to either build up that 305 or swap in an LT1. Either way, your looking at having an engine in a car it was never designed for. Both ways will have draw backs. The LT1 will be sort of over-built for the 260/300 range and *might* last longer than a built up 305. Certainly, the T5 tranny is assumed by most people to be a liability. Talk to Bryan White in MW (roadracerwhite) about doing an LT1 swap in 3rd gen. I truly believe a 3rd gen/LT1 combo is the best car in cmc, and maybe even AI. Look at what TJ did with his firechicken in MW/GL, and it's just a 305. 3rd gen firebirds have a .32Cd, the lowest of any production pony car evar. Given that we all have to run the same hp/weight ratio, aero is about the only advantage one car can have over another. You might want to look at frrax.com and read some of the build up threads for 4th and 3rd gens. Alan Blaine is a great resource for information too. Quote Link to comment Share on other sites More sharing options...
APatelIroc Posted March 8, 2011 Author Share Posted March 8, 2011 Thanks for the info! I am def. not going to rush into it, as much as i would like to. I've been on frrax here and there but never really followed a build, i'll check it out for sure. Quote Link to comment Share on other sites More sharing options...
nape1548534725 Posted March 10, 2011 Share Posted March 10, 2011 K.I.S.S. - Carburetors don't have limp mode or Check Engine lights. It's a lot quicker to change a carb and stab a distributor then it is to figure out which injector you're having a problem with or if your optispark just took a crap. I agree with the T56 though if you don't mind the weight. I had 3 T5s kicking around the garage most of the time: The broken one, the one in the car, and one fresh from the junkyard. Quote Link to comment Share on other sites More sharing options...
mitchntx1548534714 Posted March 10, 2011 Share Posted March 10, 2011 K.I.S.S. - It's a lot quicker to change a carb and stab a distributor then it is to figure out which injector you're having a problem with or if your optispark just took a crap. Pyrometer on the exhaust will tell you which injector isn't firing and it's two pink wires (one for the left bank and one for the right bank) that power them. Pull the ICM plug and look for 12V on wire A and wire B and as you are cranking AC voltage on B (the plug is labeled). If you don't have the AC voltage on B, then it's the Opti or the harness. Opti spark has gotten a really bad rep when in fact they are quite reliable if properly installed and sealed. Quote Link to comment Share on other sites More sharing options...
AllZWay Posted March 10, 2011 Share Posted March 10, 2011 K.I.S.S. - Opti spark has gotten a really bad rep when in fact they are quite reliable if properly installed and sealed. Quote Link to comment Share on other sites More sharing options...
Adam Ginsberg Posted March 10, 2011 Share Posted March 10, 2011 K.I.S.S. - It's a lot quicker to change a carb and stab a distributor then it is to figure out which injector you're having a problem with or if your optispark just took a crap. Pyrometer on the exhaust will tell you which injector isn't firing and it's two pink wires (one for the left bank and one for the right bank) that power them. Pull the ICM plug and look for 12V on wire A and wire B and as you are cranking AC voltage on B (the plug is labeled). If you don't have the AC voltage on B, then it's the Opti or the harness. Opti spark has gotten a really bad rep when in fact they are quite reliable if properly installed and sealed. Different strokes for different folks. Fernandez can't spell "carb", and has seizures even thinking about how to go about changing jets. The simplicity of a carb is unbeatable, IMO. However, I've spent plenty of time with EFI motors, and they do have value. FWIW, my decision to run carbed was simple - my car came with a carb, and I can't justify the costs to convert to EFI. Quote Link to comment Share on other sites More sharing options...
ShadowBolt Posted March 11, 2011 Share Posted March 11, 2011 K.I.S.S. - Carburetors don't have limp mode or Check Engine lights. It's a lot quicker to change a carb and stab a distributor then it is to figure out which injector you're having a problem with or if your optispark just took a crap. I agree with the T56 though if you don't mind the weight. I had 3 T5s kicking around the garage most of the time: The broken one, the one in the car, and one fresh from the junkyard. Get Tony at Astro to build you an A5 (out of a T5) and forget about trans. problems. He can build them to handle three times what a CMC2 car puts out. Weighs way less than the T56 and shifts like butter. http://www.atomicperformance.com/astroperformancewarehousea-5transmission550hp425ftlbstorquet-5.aspx JJ Quote Link to comment Share on other sites More sharing options...
APatelIroc Posted April 6, 2011 Author Share Posted April 6, 2011 Well, its been a while but i just recently acquired an 89 RS roller with a perfect body and no rust anywhere. I also picked up, the same weekend, a complete LT1/T56, driveshaft, and disc brake rear end all from the same 94 formula with only 28k miles I heard the engine running before it was taken out and was excellent. only issue is the passenger exhaust manifold needs replaced or the gasket went bad. Now i just need to figure out where/how to get more time in the day Quote Link to comment Share on other sites More sharing options...
Members Al F. Posted April 7, 2011 Members Share Posted April 7, 2011 Nice! I think that'll make a great combo. Quote Link to comment Share on other sites More sharing options...
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