Twin turbo plans

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dustbull

dustbull

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Hey guys, First off, sorry for all of the questions and long post... It's a ways off, but I'm starting to think about a turbo setup for my 70 duster. I will be putting a t56 six speed in over the next few weeks, after that i will be piecing together an efi system. Finally, i would like to install a turbo system within a year or so if all goes well. Because it is a manual i think it would be best to run a twin turbo setup to reduce turbo lag. I think i am basically going to follow Mad Dart's lead to a 'tee' (thanks for making such a detailed thread on your build!!)
A bit of relevant info on the engine:
4" stroke 'Cast Steel' crank, 6.123" forged I-beam rods, 4.040" forged KB pistons (-20.5cc dish), Edelbrock performer rpm heads (63cc combustion chamber), and ARP main studs
I will later be installing ARP head studs with new cam, and head gaskets.

Now my questions: I have been playing with different thicknesses of head gaskets on compression calculators online. currently I have about 9.8:1 compression (0.040" thickness head gasket). I can find a 0.06" thickness head gasket to get me 9.44:1 compression. I also found these solid copper head gaskets that are 0.080"-0.092" thickness which would be 9.1: or lower compression: http://www.scegaskets.com/Shop/Control/MainMenu/fp/tcat/259890/seo/1/sfv/32777/page/2/SFV/32777

Does anyone know if these gaskets are reliable, or recommended for boost/street applications? Does anyone know of any head gaskets that are 0.080" or thicker that would work for a street application?
Finally, i am a little bit concerned about the cast steel crank and the main studs holding up to this power, whats your guess on how much power/boost the lower end can handle safely...id like to get 10psi and/or maybe 650hp at the crank...Thanks for your input!
 
I think 10psi is under your components breaking point. But I would be a little suspect on your block. 650 is alot of HP for a stock block. With all the money you are spending, consider an X or R block. Copper gaskets are bulletproof if you can get them to seal, shouldn't be a prob with new AL heads, but be careful of the annealed portion of a used head where it has been compressed over the old head gasket fire ring, sometimes it has a depression there. A 6 speed with a turbo sounds like a lot of shifting. Turbos love to work against something, ie a low rear gear or a wide ratio gearbox. twins would help with the lag, but a properly sized single will work as well with less plumbing. And lastly, buy your injectors (and ECU capability, ie 3 BAR MAP) to the highest power level you think you'll achieve, now and in the future. Its pretty EZ to duty cycle down a large injector set for lower HP, but harder (if not impossible) to raise small injectors to new power gains without exceeding their D.C. ratings. Keep posting your progress.
 
pishta said:
I think 10psi is under your components breaking point. But I would be a little suspect on your block. 650 is alot of HP for a stock block. With all the money you are spending, consider an X or R block. Copper gaskets are bulletproof if you can get them to seal, shouldn't be a prob with new AL heads, but be careful of the annealed portion of a used head where it has been compressed over the old head gasket fire ring, sometimes it has a depression there. A 6 speed with a turbo sounds like a lot of shifting. Turbos love to work against something, ie a low rear gear or a wide ratio gearbox. twins would help with the lag, but a properly sized single will work as well with less plumbing. And lastly, buy your injectors (and ECU capability, ie 3 BAR MAP) to the highest power level you think you'll achieve, now and in the future. Its pretty EZ to duty cycle down a large injector set for lower HP, but harder (if not impossible) to raise small injectors to new power gains without exceeding their D.C. ratings. Keep posting your progress.
Click to expand...

Remember that Boosted Power is Linear and the "Shock Factor" is basically none. 650 HP on a stock block boosted will live for a very long time. There is a member here that built a 340 Twin Turbo with a stock crank & rods, W2 Heads that made 911HP to the tires and it never blew up. I truly believe that people under estimate how strong the mopar small block really is.

On mine I am anticipating 850Hp and over that TQ to the tires. I am using a 360 Block/410 CI with a Scat Forged 4" Crank, Falcon H Beam Rods and Wiesco Forged Eliptical Dish Pistons, Indy RHS/X Heads done by Brian at IMM Engines using Cometic Head Gaskets and ARP Head Studs. The machining was done with the use of the Cometic Gaskets in mind ahead of time, super smooth cut on both the block and the heads. I had Brian Line Hone the Mains with ARP Studs I also had him Line Hone the Cam Journals. I recommend doing this on ALL engines. Also using a Solid Roller Cam. I have build a few SBM now and this engine spins super easily, easier than any engine I have had to date, BIG DIFFERENCE. I believe it has to do with the Cam Journals being Line Honed!! You can grab the crank with the pan off and spin it no problem at all. The key is good machining and to keep the intake charge as cool as possible to avoid any chances of detonation. Detonation will Kill any engine quickly. Just my 02 cents....

Ohhh and you can get thickness from Cometic in any size you like. Call Don at 4secondsflat.com
Custom Cut Cometic head gaskets - Available thicknesses, .027", .030", .036", .040", .045", .051", .060", .066", .070", .075", .080", .086", .092", .098", .120", .140".
 
Thanks for the quick response guys! The short block was professionally built and done rite at a reputible shop; the block was decked, and line honed (i believe the cam journals were line honed as well). The original plan a couple years ago didnt involve a turbo, which is why im trying to get the compression down as much as i can. Would there be any issues running at 9.44:1 compression with 10psi through an intercooler on 93 octane pump gas compared to running closer to 9:1 compression?

Rite now the engine has 23,000 miles on it, making 350hp/430tq at the wheel. It doesnt need to be faster, but given the oppurtinity why not tap into that extra potential that boost can uncover...
 
Thanks for the Cometic gasket info, thats great to know; just what i was looking for! I was also thinking of running meth injection if i got hooked on boost and wanted more for the track or something haha
 
U may want to think about O ringing the block isky makes two different size tools for different bore size also I'm using a Hussey Copper gasket do a search on the net they offer a endless size options there is about a week turn around on your order here's a link to some pics of my /6 turbo build also u want to seal the water jackets with a product with Hylomar
Just my opinion!
Aaron aka turbo toad


http://s1109.photobucket.com/albums/h431/srixon4406
 
Thanks Aaron, but theres something about cutting into the block that makes me cringe..I wont be running any crazy boost, hopefully ill be ok without o-rings.

I did a little forum searching and am now trying to figure out the turbos, I have a forced induction book that ive been meaning to re-read after finals are over for this semester, but so far from reading other peoples builds/experiances i think im looking at a pair of ebay GT35's. Mad Dart, have you purchased your turbos yet, and if so would you mind telling me who from?
 
dustbull said:
Thanks Aaron, but theres something about cutting into the block that makes me cringe..I wont be running any crazy boost, hopefully ill be ok without o-rings.

I did a little forum searching and am now trying to figure out the turbos, I have a forced induction book that ive been meaning to re-read after finals are over for this semester, but so far from reading other peoples builds/experiances i think im looking at a pair of ebay GT35's. Mad Dart, have you purchased your turbos yet, and if so would you mind telling me who from?
Click to expand...

Yes I have bought them. I forgot who from but all the information is right here in this thread.................

Click right here:::: http://www.forabodiesonly.com/mopar/showthread.php?t=116512
 
Thanks..last night was a long night. Its quite obvious you had already bought the turbos-theyre in your avatar and being mocked up in like your entire thread..i dont know what i was thinking haha. Just looking at the pictures, your turbos have the same "turbocharger" tag as what i am looking at; thats the brand that i have heard other people say worked for them too...

EDIT: i may just be going with twin GT45's as well after reading this thread on turboforums (that i see you have posted on as well) :
http://www.theturboforums.com/smf/index.php?topic=96046.550
"[The GT35's] are not as good quality i have a few left here. but the gt45 are just built like tanks. they are heavy and from what i have seen so far very stout. I only have had 3 failures out of 250 sold"
 
...or a single holset hx55, it's about the same price as twin eBay gt45's, but I'll have to look into it more after I get closer
 
dustbull said:
...or a single holset hx55, it's about the same price as twin eBay gt45's, but I'll have to look into it more after I get closer
Click to expand...

Something to think about is if you go a big single you are going to have a very hard time getting a 5" Exhaust pipe out past the firewall. Most guys dump the 5" Exhaust right in front of the motor just at the K frame, no muffler at all.

Look at this one, he had to cut it up pretty good.

http://www.forabodiesonly.com/mopar/showthread.php?t=119353
 
Yea, very true, but either way i know/think i can make a 90 degree with the exhaust pipe coming out of the turbo and run it through a hole in the inner fender, and bring it back tucked up in the fender, down and out in the quarter panel behind the front tires. A 6-8" long glass pack may be able to fit in that configuration...I dont care much about potentially having to cut anything up if im going to stick with that configuration, im more concerned about reliability, performace, and streetability in that order.
 
FWIW the cast steel crank is gonna be your biggest issue. Most are only rated at 500hp at the crank, and a fairly stout NA 408 is already right there. A couple of turbos should easily surpass that. What brand is it?
 
Thats what i was thinking; its a Scat Cast Steel crank...And taking the 18% parasitic drivetrain loss i am rite at 500hp crank rite now already.

The other thought i have though is What Mad Dart had mentioned earlier in that turbocharging isnt as harsh of a power adder as others- the boost cushions the piston on its travel...
 
dustbull said:
Thats what i was thinking; its a Scat Cast Steel crank...And taking the 18% parasitic drivetrain loss i am rite at 500hp crank rite now already.

The other thought i have though is What Mad Dart had mentioned earlier in that turbocharging isnt as harsh of a power adder as others- the boost cushions the piston on its travel...
Click to expand...

Less initial shock to the rotating assembly. Go to Youtube and watch the boosted cars race. Watch how smooth the power comes on and then takes over!

This guy in the first 2 videos is using the same turbo's I am on a 468CI BBC. Runs 8.8 in the quarter.

[ame="http://www.youtube.com/watch?v=_6VdAHJFh3Y"]YouTube - ‪Mike's 1967 Ebay Twin Turbo Powered BBC‬‏[/ame]

[ame="http://www.youtube.com/watch?v=npwI7gJRTNw&feature=player_embedded"]YouTube - ‪47 Street car Shoot-Out Edm‬‏[/ame]

This guy is using the only 1 of the same turbo's I am using along with a 75 Shot of Dry Nitrous, still comes on smooth and lifts the tires.

[ame="http://www.youtube.com/watch?v=wTV8QTIVYB0&feature=player_embedded"]YouTube - ‪michasmovie.wmv‬‏[/ame]
 
Mad Dart said:
Remember that Boosted Power is Linear and the "Shock Factor" is basically none. 650 HP on a stock block boosted will live for a very long time. There is a member here that built a 340 Twin Turbo with a stock crank & rods, W2 Heads that made 911HP to the tires and it never blew up. I truly believe that people under estimate how strong the mopar small block really is.

On mine I am anticipating 850Hp and over that TQ to the tires. I am using a 360 Block/410 CI with a Scat Forged 4" Crank, Falcon H Beam Rods and Wiesco Forged Eliptical Dish Pistons, Indy RHS/X Heads done by Brian at IMM Engines using Cometic Head Gaskets and ARP Head Studs. The machining was done with the use of the Cometic Gaskets in mind ahead of time, super smooth cut on both the block and the heads. I had Brian Line Hone the Mains with ARP Studs I also had him Line Hone the Cam Journals. I recommend doing this on ALL engines. Also using a Solid Roller Cam. I have build a few SBM now and this engine spins super easily, easier than any engine I have had to date, BIG DIFFERENCE. I believe it has to do with the Cam Journals being Line Honed!! You can grab the crank with the pan off and spin it no problem at all. The key is good machining and to keep the intake charge as cool as possible to avoid any chances of detonation. Detonation will Kill any engine quickly. Just my 02 cents....

Ohhh and you can get thickness from Cometic in any size you like. Call Don at 4secondsflat.com
Custom Cut Cometic head gaskets - Available thicknesses, .027", .030", .036", .040", .045", .051", .060", .066", .070", .075", .080", .086", .092", .098", .120", .140".
Click to expand...
What in God's name is that motor with the twin turbos? Bill
 
I will completely agree about the linear power and less shock on the crank. But the crank is still seeing the high twisting loads and stresses. IMO I wouldn't run the cast crank in a boosted situation. I'm in the same boat, I have a cast Eagle stroker sitting here and trying to decide what to do with it. I also have a bullseye S372R sitting here that's begging to get used.
 
lucky13 said:
I will completely agree about the linear power and less shock on the crank. But the crank is still seeing the high twisting loads and stresses. IMO I wouldn't run the cast crank in a boosted situation. I'm in the same boat, I have a cast Eagle stroker sitting here and trying to decide what to do with it. I also have a bullseye S372R sitting here that's begging to get used.
Click to expand...

I wouldn't run a cast crank either but there are quite a few guys out there running 15PSI successfully with them.
 
yeah I've read a few threads where guys have been using cast cranks. In my own personal experiences (I work part time at a friends machine shop, for about 5 years now), I know that when eagle says 500hp they mean 500hp. I'm sure the scat would hold up to more.
 
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