Moparts

Gen 3 Hemi turbo update

Posted By: Dave_S

Gen 3 Hemi turbo update - 01/04/14 08:30 PM

Thought I would post an update on my Dart and to let everyone know we survived the ice storm. Seven days with no electricity, 20*F and a heat pump is no fun!
The build pics are here; https://board.moparts.org/ubbthreads/show...amp;Search=true

Made it to the track a few times. First trip, the Tech guy spouted "Don't see an LS motor in a Dodge everyday" I set him straight....he's a chevy guy.....so what do you expect. Then my new Ebay mini alt. caught fire....very un-cool.
Second time out four of my awesome Ebay 120 lb/hr fuel injectors decided to quit....totally dead!.....starting to see a pattern here! I did get down the track that day and confirmed the trans worked at least.
New 160 lb/hr injectors (borrowed) installed and re-tuned. Got down the track a few times...11.5@120...lots of sputtering and misfiring. Good news is the launch control worked awesome. The turbo spooled up super fast. The boost was limited to 10 psi. After checking the datalog and tuning and tuning some more the miss at 5000 was still there. We are thinking it may be a valve spring issue. I have a set of stock 6.1 springs in there, which would be OK if it was NA. I did not consider the effects of boost when I selected these springs. I have a new set to go in along with some stouter pushrods.
I was impressed it still had enough bottom end to still pull the wheels a little bit. Obviously, it needs more work to reach it's full potential.
Something I didn't realize is the lack of colder plugs for these engines. There are some fine wire ones avail., but from what I read that's a no-no for turbo cars. The older heads (pre 2009) and SRT's use a tapered seat, while the Eagles use a gasket.
Over the winter: New valve springs and push rods, trans cooler, new rear tires and going to reposition the turbo for more front tire clearance.

Thanks

Dave

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Posted By: 72Swinger

Re: Gen 3 Hemi turbo update - 01/04/14 08:36 PM

Well you should have enough injector for 1300hp now.
Posted By: Duner

Re: Gen 3 Hemi turbo update - 01/04/14 09:18 PM

Sounds awesome for a setup there.

What kind of plug gap are you running with it?

I'm VERY interested in how this works for you since it's the same direction I plan on heading with mine - as in a Megasquirted single-turbo Gen 3 Hemi.
Posted By: Dave_S

Re: Gen 3 Hemi turbo update - 01/05/14 12:11 AM

Thanks
I started with .040 and worked my way to .020. Using stock coils and MS3 for ignition control.

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Posted By: Duner

Re: Gen 3 Hemi turbo update - 01/05/14 12:25 AM

I'd say valve springs would be a pretty good guess.

When my Magnum had valve spring issues related to boost - it would rev to 7K at 6 psi of boost but wouldn't rev past 5500 at 12 psi of boost. I kept thinking it was ignition until after I had replaced every single ignition component in the chain. I just knew it couldn't have been my valve springs because they were new... until I actually checked them and saw that some were junk. New springs and it'll rev past 7K at 18 psi of boost - no problem.
Posted By: SLOW67

Re: Gen 3 Hemi turbo update - 01/05/14 01:28 AM

How have you liked the MS3? Is this your first expierence with efi? I'm thinking of going the MS route because it is so much cheaper than the alternatives.
Posted By: Dave_S

Re: Gen 3 Hemi turbo update - 01/05/14 01:46 AM

My 512 had MegaSquirt on it, but it was fuel only. I really like it because it forces you to get right in there and mess with stuff. That's how you learn. Well, that's how I learn. Hopefully I will learn how NOT to melt my pistons!.
It took me awhile to get the ignition sorted out, but its good now.

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Posted By: hemidup

Re: Gen 3 Hemi turbo update - 01/05/14 02:46 AM

Nice! Very nice FWIW, I ran 80 psi Ford injectors on a boosted G3 that were good to 950 hp however the duty cycle was maxxed at 100% with 58 psi fuel pressure. I then switched over to 120's and at the same hp level those were only at 60% duty cycle at the same fuel pressure. I'm thinking with your borrowed injectors your spray pattern isn't all the greatest. Also if your using NGK spark plugs, they don't recommend a gap any tighter than .035" cause it may cause stress cracks on the ground strap. I use Brisk non projected tip spark plugs that come pre gapped at .032" and you can gap than tighter than that. Most boosted guys I know run them between .028 and .030". Since I have Brisk tapered plugs I can't help you with a part number, but here's the part number that I use so maybe you can get a X reference number for the ones you need. Brisk RR14S Silver. Manley 221430 and Pac 1409 springs have the highest spring rates out there for the G3's and and will work just fine with your camshaft. Again, nice build so keep on keepin on.
Posted By: Dave_S

Re: Gen 3 Hemi turbo update - 01/05/14 05:05 AM

Thanks

I was worried about those the injectors having issues with small pulse widths at idle etc. but these idle great. Brisk does make a gasketed plug, but the price almost knocked me over! They want $16 each. I know this is an expensive hobby, but that is had to swallow, especially for a consumable part like a spark plug.

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Posted By: 72Swinger

Re: Gen 3 Hemi turbo update - 01/05/14 05:06 AM

Quote:

My 512 had MegaSquirt on it, but it was fuel only. I really like it because it forces you to get right in there and mess with stuff. That's how you learn. Well, that's how I learn. Hopefully I will learn how NOT to melt my pistons!.
It took me awhile to get the ignition sorted out, but its good now.


Are you running stock exhaust gaskets with your headers? Curious how well they have handled the heat? My guess is good?
Posted By: Duner

Re: Gen 3 Hemi turbo update - 01/05/14 08:39 AM

I was crutching my EFI system before with an aux fuel pump and FMU with too small of injectors because the 24# injectors were all the factory PCM could trim to make idle. It took 160 psi of fuel pressure to get to 700hp! LOL Who'd have thought you could get 4200# worth of truck to go 10.61 @ 133.65 mph with 24# injectors? hahaha (I know, nobody in their right mind would have tried!)

Now with MS3X I run the 66# injectors sequentially at 70psi of base pressure with a 1:1 regulator for 88psi thru the traps.

For my limited experiences with EFI it's been a fantastic opportunity to use a system that more or less tunes itself after you give it some AFR targets for specific rpm and loads. I'm quite impressed to say the least.
Posted By: TheOtherDodge

Re: Gen 3 Hemi turbo update - 01/05/14 02:44 PM

Good to see you and the project made it! Just have to sort the tune out now.
Posted By: TheOtherDodge

Re: Gen 3 Hemi turbo update - 01/05/14 02:49 PM

You guys have run some crazy tunes!

Plain ole autolites at .020 and 90 lb injectors at 45 psi in my junk...
Posted By: Duner

Re: Gen 3 Hemi turbo update - 01/05/14 05:36 PM

I too am running the cheap Autolite plugs - but at .032" gap. No expensive plugs for my heap.
Posted By: MattW

Re: Gen 3 Hemi turbo update - 01/05/14 08:02 PM

Any ETA on your hemi build?
Posted By: Duner

Re: Gen 3 Hemi turbo update - 01/05/14 08:06 PM

No real ETA. I just keep watching for the right opportunity to happen. I manage to get lucky sometimes.
Posted By: Dave_S

Re: Gen 3 Hemi turbo update - 01/08/14 02:42 AM

I have the Nextek 221431 springs ready to go in. Any preferences for push rods?
Here's a pic of the rod and piston.

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Posted By: hemidup

Re: Gen 3 Hemi turbo update - 01/08/14 04:21 PM

Dave, Forgot you had the Eagle heads so your valve spring choice was correct.

If your engine combo is a pre 09 block, 6.1 cam and Eagle heads, plus I don't know the thickness of your head gaskets so I would go with a custom length pushrod.

The base circle of an oem 6.1 cam as well as aftermarket cam's are smaller than an oem 5.7. The factory deck height of the Eagle head is .100" shorter than a 5.7 or 6.1 and the rockershafts of the Eagle head are spaced wider than the 5./6.1's and again, don't know the thickness of your head gasket.

The trick is figuring out the pushrod length you need without pulling the head to access the lifters to place in a makeshift solid lifter. A little home brew engineering, checker valve springs, aluminum tubing or aluminum welding rod has worked for me to get the total pushrod lengh at zero lash which then I relayed my info to Smith Bros for the correct pushrod. I can't recall the distance from the top of the lifter to the bottom of the cup, but I do remember there is .165" of lifter cup travel. I've always gone with .040"-.060" preload.
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