I'm attempting to get the 282 to hold lots of power by keeping the instant-torque down and reducing the MOI (Moment Of Inertia). Horsepower doesn't kill tranny's (to a point), transient loading does... that means a large amount of torque is applied to the tranny all at once, instead of progressively. This typically happens two ways; Via larger displacement engines that make lots of throttle-on torque, and via heavy rotating parts before the transmission (clutch assembly and crank) which have a high MOI and so don't want to stop spinning as easily. That extra energy is immediately transferred to everything downstream (the first, and often weakest in these cars, being the tranny) during launches and shifts. Those factors together are what cause many of the SBC cars to shred 282's if not driven lightly. Many of those swaps use massive flywheels that are WAY too heavy and large for this application, and that combined especially with 5.7 liters of TPI torque makes for a bad combo.

The reason I want to keep the 282 is mainly that it's very lightweight, only 85 lbs. dry (I think it was, maybe 95). Also, the car is already set up for it of course.

The 3200 will use a 76mm (2.8) crank and the twin-disk clutch, both of which weigh MUCH less and keep the MOI MUCH lower than a lot of the high-hp combos on here. The one disadvantage to this twin-disk in that respect is that it's designed to hold LOTS of torque and has solid hubs, and so grabs very hard without slippage, and that puts a heavier transient load on the trans than a lower-capacity clutch (like the Clutchnet 6-puck sprung-hub clutch that's in MIDTRBO now). I'm hoping the reduced MOI can cancel that out, though, while holding the higher power. Time will tell, and if the tranny goes kaput, my friend Will (username Will on here) has some ideas for the next one (and for his 282 behind his high-compression Northstar).

That setup will come together after this TGP shortblock w/Clutchnet clutch is tuned well and I have a better idea of some specifics I want to change for the 3200 like the cam, static compression, porting, etc. I won't post up my power estimate for that because I don't want to cause any controversy, especially if I don't make it.
With the TGP shortblock I'm hoping for 350whp on pump gas when tuned and with the water/air IC setup (which isn't the way it's going to leave Dave's shop... that'll be a very tuned-down version for reliability's sake). When it comes home without an IC and with the 8.7psi WG spring in it, I estimate that it'll make around 230whp, and that is, by far, as low as it should ever be.

[This message has been edited by ALLTRBO (edited 09-15-2010).]

quote Originally posted by ALLTRBO: I'm attempting to get the 282 to hold lots of power by keeping the instant-torque down and reducing the MOI (Moment Of Inertia). Horsepower doesn't kill tranny's (to a point), transient loading does... that means a large amount of torque is applied to the tranny all at once, instead of progressively. This typically happens two ways; Via larger displacement engines that make lots of throttle-on torque, and via heavy rotating parts before the transmission (clutch assembly and crank) which have a high MOI and so don't want to stop spinning as easily. That extra energy is immediately transferred to everything downstream (the first, and often weakest in these cars, being the tranny) during launches and shifts. Those factors together are what cause many of the SBC cars to shred 282's if not driven lightly. Many of those swaps use massive flywheels that are WAY too heavy and large for this application, and that combined especially with 5.7 liters of TPI torque makes for a bad combo. The reason I want to keep the 282 is mainly that it's very lightweight, only 85 lbs. dry (I think it was, maybe 95). Also, the car is already set up for it of course. The 3200 will use a 76mm (2.8) crank and the twin-disk clutch, both of which weigh MUCH less and keep the MOI MUCH lower than a lot of the high-hp combos on here. The one disadvantage to this twin-disk in that respect is that it's designed to hold LOTS of torque and has solid hubs, and so grabs very hard without slippage, and that puts a heavier transient load on the trans than a lower-capacity clutch (like the Clutchnet 6-puck sprung-hub clutch that's in MIDTRBO now). I'm hoping the reduced MOI can cancel that out, though, while holding the higher power. Time will tell, and if the tranny goes kaput, my friend Will (username Will on here) has some ideas for the next one (and for his 282 behind his high-compression Northstar). That setup will come together after this TGP shortblock w/Clutchnet clutch is tuned well and I have a better idea of some specifics I want to change for the 3200 like the cam, static compression, porting, etc. I won't post up my power estimate for that because I don't want to cause any controversy, especially if I don't make it. With the TGP shortblock I'm hoping for 350whp on pump gas when tuned and with the water/air IC setup (which isn't the way it's going to leave Dave's shop... that'll be a very tuned-down version for reliability's sake). When it comes home without an IC and with the 8.7psi WG spring in it, I estimate that it'll make around 230whp, and that is, by far, as low as it should ever be.

Lotta really good info that I "knew" but didn't quite make sense, me likey. I knew torque (don't know why I said HP) was the notorious transmission killer, but I didn't know about the MOI and rotational mass issues that (if I understand correctly, and may even be an over-simplification) multiply the amount of torque actually applied to the transmission and on down the line. Kinda close in my understanding?

I think I may be as excited about this as you are. LOL

[This message has been edited by Rallaster (edited 09-15-2010).]

is that braided Teflon being used for the wastegate dump ?
keeping in mind that the waste gate only opens when things are hot...
how much heat can that braided stuff handle ?

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87 Fiero GT 5sp with Vortec L35 4300 Turbocharged V6
Bully Stage 2 clutch
Syclone intake manifold and engine management with Moates adapter and chip burner
Air/water intercooler and Devil's Own progressive water/alky injection
50lb injectors, 3 bar map sensor, Walboro fuel pump and Jabasco Intercooler pump
LM1 wideband on custom manifolds and 3" stainless exhaust system
T31 P trim T04B H3 turbo and a S10 caliper conversion.
Murphy's Constant Matter will be damaged in direct proportion to its value
Murphy's Law of Thermodynamics Things get worse under pressure.
Arthur C. Clarke "Any significantly advanced technology is indistinguishable from magic"

Just read thru your build thread. This a very well built car so far. At the rate youre going Im sure it will continue to improve. The Haus really does amazing work with so much attention to detail. That exhaust is amazing! The turbo setup is exactly how i would have liked to do mine if i only had the resources (time, money, patience).

Im running the same Clutchnet setup on my 3500T. It holds well but can be a little pedal heavy in stop and go traffic, also chatters a little when cold. Personally I'd save that twin-disk setup for your "future" build. It probably wont be very streetable and harder on the trans than a single disk, sprug hub setup.

Have you researched using a 2.8 crank in a 3500 block? Im not sure of the compatability. I have always wanted to build a destroked 3400 (which i think is a 3.0L) that could handle 8K and lots of boost. Good luck with the 3200 it will be a beast if you do it. Keep in mind the HM282 doesnt shift well above 6500rpms. I believe 7k is about the limit. A HM284 would work great at high rpm's but is kinda hard to find nowdays.

My setup definatly isnt as nice but it works. I originally built it this way to fit around a 3100/4t60E. Then had engine problems so swap to a 3500. Then had trans failure so i swapped to a fwd 5 speed.

[I have a spare 3500 UIM for sale just incase your interested ]

JoeCooley

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1987 SE / Fastback - 3500 Turdbowd / '92 5-speed swap

No bandwagon here...

quote Originally posted by 87_special: Just read thru your build thread. This a very well built car so far. At the rate youre going Im sure it will continue to improve. The Haus really does amazing work with so much attention to detail. That exhaust is amazing! The turbo setup is exactly how i would have liked to do mine if i only had the resources (time, money, patience). Im running the same Clutchnet setup on my 3500T. It holds well but can be a little pedal heavy in stop and go traffic, also chatters a little when cold. Personally I'd save that twin-disk setup for your "future" build. It probably wont be very streetable and harder on the trans than a single disk, sprug hub setup. Have you researched using a 2.8 crank in a 3500 block? Im not sure of the compatability. I have always wanted to build a destroked 3400 (which i think is a 3.0L) that could handle 8K and lots of boost. Good luck with the 3200 it will be a beast if you do it. Keep in mind the HM282 doesnt shift well above 6500rpms. I believe 7k is about the limit. A HM284 would work great at high rpm's but is kinda hard to find nowdays. My setup definatly isnt as nice but it works. I originally built it this way to fit around a 3100/4t60E. Then had engine problems so swap to a 3500. Then had trans failure so i swapped to a fwd 5 speed. [I have a spare 3500 UIM for sale just incase your interested ] JoeCooley

Cool! Thanks for chiming in. Do you have a thread about your car or can you give more info? I'd like to hear all about it. How did the 3100 compare to the 3500? Turbo specs? Boost level? Spool time? Tuning? C'mon, give it up!

I do expect the Clutchnet clutch to behave just how you described, thanks for the confirmation. It'll hold everything the TGP shortblock can throw at it, so I definitely don't plan on swapping to the twin-disk until I install the 3200. You're correct, that clutch is going to be a wild beast, it'll be hard to tame, but necessary. My only major concern with it is the instant clamping between shifts, that does indeed put more transient loading through the tranny. However, the MOI is going to be insanely low with this setup, and more-so because I'll be upgrading to the aluminum pressure plate to save even more weight. I'm hoping that this will make up for the slight slippage that organic single disk clutches have.

Yes, the 2.8 crank will drop right into the 3500 block, as will the other 60V6 cranks. The difference lies in the stroke (of course) and the rod journal diameter, which is okay since I won't be using any of the 3500 rotating assembly.
WOT-Tech sells Diamond forged pistons for the 3400, and can order them .100" over. That .100 will make up for the larger bore of the 3500 block plus an additional clean-up bore of about .020". It will come out to 3199cc's which isn't much less than the 3350cc's of the "3400", but it will love to rev higher.

The reason for using oversize 3400 pistons instead of 3500 pistons is that the wrist-pin heights are different between the two. The 3400 pin height sits perfect with the 76mm stroke to throw in a set of (very stout) off-the-shelf 5.85" small-journal small block Chevy rods. Those will need to be narrowed slightly to fit the 60V6 crank journal width and a bushing added to the small end to match the 3400 pin diameter. Both of those are simple machine operations that any decent machine shop can do on the cheap.
Slightly playing around with the Cometic MLS head gasket thicknesses along with the deck height (depending on whether or not it'll need to be decked) will net me around an 8.7:1 SCR with the "9.5:1" Diamond pistons (their rating is for a stock 3400 stroke. Destroking an engine will lower the SCR by the same percentage as the reduced stroke).
The 2.8 crank must be from a DIS 2.8 because of the internal crank trigger. The earlier one (like the stock Fiero 2.8) can be used, but to run DIS with it an external crank trigger setup must be used.

The 282 in stock form doesn't like to shift very high, but the reduced MOI of the clutch and smaller crank will raise the limit because the synchros don't have to work as hard to slow down the momentum at those RPM's, and that momentum decrease drops off the RPM's quicker anyway, reducing the synchros need to 'pull down' the RPM itself. Will has a few tricks up his sleeve as well, he's VERY familiar with the inner workings of the 282. Between these mods, I think 7500rpm shifts shouldn't be a problem and I'm hoping it might work to 8000, because the 3200 sure will with the right valvetrain, cam, and porting.

Thanks but no thanks on the spare 3500 UIM, I'm keeping the custom modified 3100 UIM. I hear the 3100/3400 UIM's don't flow any less than the 3500's, they're just a bit more peaky than the 3500's. At any rate, I plan on getting it ported so it'll flow very very well.

Thanks again for the comments!

[This message has been edited by ALLTRBO (edited 09-24-2010).]