Turbo-bowtie

My brother and I have set out to see at what power a NV3500/HM290 will break and wbat exactly is the first thing to break. Right now the setup is a fully stock gen 3 5.3 with an ebay gt45 turbo and a 1990 HM290 in a 94 c1500. It is currently at 5psi. Milleage on the trans is unknown but whines in 1st and 2nd. The trans has been in for 1 week and seems fine but only time will tell. I will update this thread for changes to the setup and how the trans is holding up.

AMP-D

I will make the prediction that the cluster gear will pull away from the main shaft gears due to the cluster gear bearing design thus shearing the teeth off at least one top gear and one bottom gear.

Turbo-bowtie

Any idea how much power you believe it will hold before it gives out? Only hard numbers on power i have seen that someone pushed through an NV was somewhere around 445hp and 489tq. Everything else i have seen has been "ahh i put one behind a big block or they are junk dont use them " but no hard numbers or setup explainations or anything. But we did have a t5 out of an 87 v6 camaro that survived about 50 pulls on the street with the same setup before letting go, all it did was chew the input shaft teeth and shear the teeth off the first cluster gear.

AMP-D

Your 10 spline input shaft will probably twist about 500 lbs of torque. The cluster gear will begin to push away from the main shaft at about 500-600 lbs of torque as well depending on the weight of the truck and how well the tires put the power to the ground.

Turbo-bowtie

What are you making these predictions based on? They are quite specific.

AMP-D

20 years of experience and understanding of how components work against each other under torque loads and stress.

Turbo-bowtie

Well alright then. I hope i can prove you wrong and it will live to see 600+ but I doubt that will happen. The truck will likely never see any hard abuse on the track, It will mostly be a highway/roll vehicle. Are your numbers at the flywheel or to the wheels?

BALLSS

TQ will be harder on the NV than HP...and more so clutch dumps running a tire.

Street use and just "rolling" into the gas the NV should put up with some HP....600 may be asking to much though long term

but if this is a experiment in finding out how much power for how long...go for it.

merim123

iTrader: (11)

protect your legs too in case things go ugly...

AMP-D

Flywheel numbers but its really based on the weight of the vehicle and several other factors. I knew a guy years ago that ran one in a swb single cab with a mild built NA 454. It lasted for a little while but ended up busting to hell. It probably made 500-550 lbs torque at the flywheel and the truck was right at 4000 lbs on street tires with a dual friction clutch in it.

Turbo-bowtie

We are just doing it as an experiment and as a possible cheaper alternative to a t56 for lower power builds. We have a vette t56 that we are converting to an f-body t56 to put in the truck. This trans was just to get the truck back driving around while we do the t56. Hell, its a 4wd unit in a 2wd truck. The NV will never see a clutch dump nor a no-lift shift. It will barely see quick shifts, just mostly single gear pulls or 2-3 or 3-4 pulls. With the odd gearing of the trans and a 3.08 rear there really isnt much shifting that can be done. Does anyone know what breaks first on these transmissions? Only thing i have come across is a guy that cracked the case in a s10

AMP-D

This is what you can expect from a NV3500 with some power being put through it.

Turbo-bowtie

Well damn.. Any idea how much power it broke at and under what circumstances? Nothing against you but i would love to hear something other than it broke under some power. Was the vehicle n/a and being launched or a big hp all motor truck towing a trailer or did it break mid pull or as soon as someone dumped the clutch on a gear change? Im just tired of hearing oh it broke under some power.

Turbo-bowtie

The trans is still holding together. It is now making 9psi and has been for a month now. Being driven every day and making atleast 2 pulls a day. Im debating on turning it up to 12psi or just leaving it at 9 and seeing if the trans will hold together. Not sure what kind of power the truck makes but I found an article where a stock 5.3 made 510 hp 530tq on 8psi.

pdxmotorhead

I've broken one behind a stock Jeep Wrangle 4.0 6 Cylinder,, we picked the parts up off the trail and put it in a 5 gal bucket. the bell housing was all that was left on the back of the motor, the yoke was still attached to the drive line.. It had about 75K miles on it offload, seldom over 5 to 10 miles an hour.. They did fine behind the Dakota V6 motors.. We think it was a bearing fail, that caused the shift fork to break allowing it in to 2 gears at once half way up a rock face.. Which locked the transmission, at about 5500 rpm with a heavy stock flywheel and clutch.. It was EPIC.. Loud..

Turbo-bowtie

well damn... Hopefully our 150k+ mile trans does not do the same. But we will see. It has been abused daily since the time it was put in with no less than 400hp and tq being put through it. Hopefully the swap from a 3.08 to a 3.42 will help it live.

Turbo-bowtie

The trans is still holding in there and still going strong. The truck is still being driven and abused a couple days a week. It is still making around 9-10 psi. The trans has seen 14 psi for 4 pulls but the afr's were getting a bit lean so its back down around 10. Still no track time. Just rolling pulls on the street. We will be getting injectors soon and will be upping the boost so hopefully it will all hold together.

Trevor Chichester

How's the trans holding up??

Turbo-bowtie

Still good. Truck is still only on 9 psi.

Michael12

how’s that trans holding up currently turboing my 5.3 in my s10 wanting too see about 550hp out of it with my nv3500 and what clutch do U have