SuperCharger to HEMI Transition?

[gbaumann]

You need a road trip to get that puppy broken in. The dyno is in hawthorne nj. We can finally meet and strap it down.

Maybe even get snarf up here with the turbo to do same day dynos. Everyones gear ratios are off now tho. JG. 4.88 BB 4.56

Baumann, your truck needs a name....

I'm in. Let's have a JeepLab Spring Dyno Day. And (to be named truck) is turning 4:10s.

[UselessPickles]

The biggest problem is the automatic transmission-- the torque converter is energy sink...

It's not just the auto trans. Manual trans produces similar dyno results. And as far as real world acceleration performance, the auto actually wins because it shifts faster.

The torque converter is not the source of the energy loss because it locks up completely at some point. At low road speeds, the torque converter is even a benefit because it lets the engine rev up to about 2500 rpm and actually multiplies torque a bit. Better torque/bower than if you were to slip a clutch at the same rpm.

I still think the manual is more fun though

I'd guess that the source of the loss is simply the heavy drivetrain components (axles, driveshafts, components in the transfer case, flywheel) with high moment of inertia. The flywheel must be quite heavy. I drove a loaner Caravan with the 3.6 pentastar, and it revved like a race car in neutral with a throttle blip compared to the Wrangler.

Before making the swap I spoke with Arrington Performance and Southern Hot Rod who both can get you to 400hp at the wheels with some limited warranty.

400 hp at the wheels with the broad torque curve of the V8 would just be insane. And probably insanely expensive.

[KaiserBill]

It's not just the auto trans. Manual trans produces similar dyno results. And as far as real world acceleration performance, the auto actually wins because it shifts faster.

The torque converter is not the source of the energy loss because it locks up completely at some point. At low road speeds, the torque converter is even a benefit because it lets the engine rev up to about 2500 rpm and actually multiplies torque a bit. Better torque/bower than if you were to slip a clutch at the same rpm.

I still think the manual is more fun though

I'd guess that the source of the loss is simply the heavy drivetrain components (axles, driveshafts, components in the transfer case, flywheel) with high moment of inertia. The flywheel must be quite heavy. I drove a loaner Caravan with the 3.6 pentastar, and it revved like a race car in neutral with a throttle blip compared to the Wrangler.




400 hp at the wheels with the broad torque curve of the V8 would just be insane. And probably insanely expensive.

Torque converts can increase the torque of the engine that is true. However, they always have a greater loss of power because of the heat issues.



And if you notice more transmissions that are marketed as automatics are getting away from the torque converter system because of the loss of power they create. Instead they are using dual clutches which have less power loss.


As for lock up torque converters they still show power losses due to the heating of the fluid within the torque converter itself. Also, that heat is usually transferred to the transmission itself more effective and another net loss of power is registered.

Usually, most of the literature on this will say that 2.5% to 5% power loss over that of a manual or AMT gearbox is shown.

However, as you correctly pointed out before the torque multiplication affect of the torque converter is why it is often used in heavy equipment applications where at low rpm the the engine's torque is too low to maintain forward motion without riding the clutch. That is why the Unimog has always had a torque converter hooked to a manual gearbox (now AMT) for use on railways and so on. Also heavy hauling vehicles usually like to have a torque converter for the same reason. But they do show greater signs of power loss overall.

I read a lot of technical stuff about these things.

Me, I think manuals are the only way to go. But, what I was saying is that if the Wrangler for some unknown reason shows such a high loss of power in the drive train as 27% then it is a good bet the Manual is at the lower end of this spectrum and the automatic is at the higher end of this statistic.

[UselessPickles]

I think an update on the status of this hemi conversion is overdue...

[gbaumann]

I think an update on the status of this hemi conversion is overdue...

Right you are sir! And no sooner than I saw your post did I receive the following video.

[gbaumann]

IT'S ALIVE! IT'S ALIVE!

https://youtu.be/lCLNjimNFUU

[UselessPickles]

Nice! How much more tidying up and testing is left to do before you can pick it up?

Are you going to do tons of driving this weekend to try to get through the entire break-in period ASAP?

[gbaumann]

Nice! How much more tidying up and testing is left to do before you can pick it up?

Are you going to do tons of driving this weekend to try to get through the entire break-in period ASAP?

I pick it up tomorrow at noon. I'll put every mile I can on her! And then report back with pics and videos.

[gbaumann]

I've got her home! Awesome driving experience so far.

[JeepLab]

Is she a rocket? The name is "cherry bomb"