Looking for Twin turbo tech and advice, Mopar build

[benno505]

I have a pro touring 68 charger with 440 stroked to 505 at the moment, But I am wanting to do a twin turbo setup for it but I do not know a lot about building such a setup so looking for and information and advice that can help me accomplishment this please.

I am a fabricator by trade and have no problems designing and fabricating my own stainless pipes and intercooler ducting etc.

I am going to be changing the engine almost completely and not utilising the current parts.

I would be hoping for around 700-900hp but street friendly with some auto-x also.

I am also currently running a beefed up mopar a833 4 speed and would like to change it out for a better box but also unsure which could hold up to the power.

Thanks

[andrewb70]

Having 505ci should make it relatively easy to get the kind of HP numbers that you are looking for. I don't know much about Mopar engines, but with aluminum heads it seems like compression around 8.5-9.0 is about what you want to run if you want to use pump gas. I don't know the octane rating in AU, but in the USA we are generally limited to 93 octane.

As for turbo sizing, I learned a lot by using the Borg Warner Match Bot online tool. There are also some videos at the bottom that go over basics that I found very useful.

http://www.turbos.bwauto.com/aftermarket/matchbot.aspx

Andrew

[benno505]

thanks for the quick reply, we are running around 98 octane but I think that is the equivalent to US 93.
Is there the need for running fancy big ported heads and crazy cams or does all that go out the window with turbos

[andrewb70]

thanks for the quick reply, we are running around 98 octane but I think that is the equivalent to US 93.
Is there the need for running fancy big ported heads and crazy cams or does all that go out the window with turbos

For the kind of power that you want to make, any decent aftermarket aluminum head will do and the cam lobes can be practically round. The engine will be very mild. I did a quick match and it looks like a pair of EFR 9180s would do the trick. With only 12 pounds of boost you'll make over 1000lb/ft of torque from 2000-6000rpm and peak out at about 1100 hp. The turbos should spool instantly.

Here is a link:

505 ci turbo match

Andrew

[HellPhish89]

controlling boost and back pressure will be very important as well.

IIRC, the bigger the waste gate you use, the finer control you have at low boost levels (reasonably speaking of course). the BoV has to be the correct size so you evac all the wasted air when the throttle closes.

[andrewb70]

controlling boost and back pressure will be very important as well.

IIRC, the bigger the waste gate you use, the finer control you have at low boost levels (reasonably speaking of course).....

That's not entirely accurate. If the waste gate is too big you can actually loose resolution of control. In other words, control will not be finer but courser. The BW matchbox that I posted actually is very sophisticated and gives approximate size of wastegate valve that should be used. Their EFR series of turbos also have high flow wastegates built into the turbine housings. Having integral wastegates really cleans up the plumbing.

Andrew

[mmosley]

700-900hp, you could probably do that with the iron heads without too much boost. Rod, pistons and rings would have to be able to take the pressure. Once you get in that range the cap walk on the mains will be a big issue and at a minimum you would want to run a main girdle if you are using a stock block. With main girdles you have to install those and line bore the mains. Of course the engine will survive at those levels without the girdle, just not live a long life.

Better plan for that power range is to start with a World Products wedge or Hemi block. They come in aluminum or cast iron. You have to choose wedge or hemi... aluminum wedge would be the lightest I suppose. 540ci is pretty easy to build, but 426-440ci would be plenty for a turbo build and you can turn more RPM with a slower piston speed. But this route is very expensive. You could then take that block well over 1000hp and never worry about it.

Transmission. The 833 probably would not survive. You can call Jamie Passon and ask him, but my guess is your duty limit is less than 700ft-lb. Clutch would have to live also. Maybe something like a G-Force transmission? http://gforcetransmissions.com/tran_gf2000.asp

Generally speaking I would take these questions over to the race section on the Moparts board.

[Nothingface5384]

No different then building any other engine except lower compression to 8.5 to 1...unless you plan to use e85..
Turbos love stroke and ya got that.
Change rear gear to something around 3.00 3.23 range as highway geara. put load on engine which spools turbos better.

Get turbo specific cam and viola

For downpipe go as big as you can fit...probably o ly 3 to 3.5?
Intercooler is always a nice addition
http://www.treadstoneperformance.com...t=Intercoolers


http://www.synapseengineering.com/
They make the best bov and wastegate for sure
But tial and turbo smart are great choices too

[HellPhish89]

That's not entirely accurate. If the waste gate is too big you can actually loose resolution of control. In other words, control will not be finer but courser. The BW matchbox that I posted actually is very sophisticated and gives approximate size of wastegate valve that should be used. Their EFR series of turbos also have high flow wastegates built into the turbine housings. Having integral wastegates really cleans up the plumbing.

Andrew

internal wastegates have their own issues if the down pipe isnt designed with it in mind; just dumping the exhaust from teh turbine and the wastegate together can cause its own set of problems. i see your point about sizing the gates.



is the extremely low 8-8.5:1 a set in stone aspect tor can it actually go to 9-9.5:1 like LSx and other engines on boost?

[andrewb70]

....

is the extremely low 8-8.5:1 a set in stone aspect tor can it actually go to 9-9.5:1 like LSx and other engines on boost?

I think the actual compression ratio will depend on the cylinder head material and combustion chamber design. I don't know enough about Mopars to give a definitive answer. I know with LSx engines, I would go with 9:1 compression for pump gas and moderate (under 18 psi) boost.

Andrew

[benno505]

thanks guys, have been very helpful so far, I will go into more details of me engine and If you guys have time you can let me know what is worthy of using or replacing, budget is no aspect but I do not want to go too crazy.

here is my current engine build.

440-505 stroker
K1 forged crank 4.25 stroke
rpm forged h beam rods 7.100
KB forged pistons 4.350
10.1 comp
Lunati, Hydraulic 300/305, [email protected], .540 lift, 300/305. 252@ .50 duration cam
pushrods comp cams magnum 3/8"
rockers comp cams roller rockers 1:5 ratio
stealth aluminium heads 80cc
valves and springs all comp cams 10 lock stainless
cometic gaskets throughout, mv high volume pump
1/2" fuel lines form tank to regulator which is race pumps
msd 6al and distributor
American powertrain billet flywheel and Kevlar clutch
diff is 8 3/4 with eaton true trac and 31 spline axles

[MonzaRacer]

After figuring out GT2871R eBay turbos in .64ar would work on my SBC project, and make 550-600+ HP.
So after doing some more research about using these same type turbos, possibly in the .86ar it seemed the pair still work and I decide to see if they would work on my stock 454.
I was working 454 stone stock, at 5 psi on intercooler. It stated even .64ar would push well over 750hp.
So the larger version should push much more power but it would take beefed up parts.
Simple 2 in 1 out intercooler available off eBay also. And are rated for 700+

[iadr]

The Chrysler block is a weak point as pointed out earlier. I can only imagine what the cost of a block is down there, but you are not going to see a reliable 800+ hp with a stock block.

Cam is too big- you want 230-234. I'd do the smallest Comp Extreme for Mopar lifter: 271 advertised, I think and 231-237 @ .050

[72BBSwinger]

Go KB water block. Then your good to 3500hp. The crank and heads are all I would re-use. Carrillo or Manley billet rods and some dished Diamond pistons. Cam wise I would have one ground to spec by a guru.