Twin or Single turbo system for a 427 or 454ci
11-26-2008, 05:30 PM
#1
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Twin or Single turbo system for a 427 or 454ci First off this is going to be a street driven car and I am looking for good street manners and the goal is 700 or so rwhp. Here's what my engine going to consist of: Beck sheet metal intake,accufab 105mm tb, C5R heads and a LSX block I haven't made up my mind if its going to be a 427 or a 454 yet. Here's my question with these cubic inches which set up would I be better of with, a TT or a single turbo system and what size turbos or turbo? I've already see some one here who has a 454 with a 106mm single turbo but it seems that his stang is a drag car. Thanks for the help.
11-26-2008, 06:40 PM
#2
Well guess say it first..You are building way way beyond any sane street car build. 427 or 454 should be easy 500 to 550rwhp or so by themselves with decent cam,heads hardly even need a turbo at all to hit 700rwhp. Course those big engines will spool up most snails really quickly. Sometimes maybe too quickly. Your hardware is for way over 1000rwhp. From personal experience much past 600rwhp is not very "streetable". Course different people have different definitions of the word. To me it means I can putter around in heavy traffic, car acts like a kitten. No lope at all,smooth idle. Pretty quiet with the cutout closed. Dont attract much attention off boost. Have a nice off boost gear like 3.42 or 3.54. So its not doggy off boost. Have decent quick spool up by like 3000 rpm in third and have a nice wide powerband from say 2000 when it starts putting out boost to 7000 redline. Have nice off boost power and torque as well.
Tiago the guy in high tech performance just did a 427 build way beyond 700rwhp with similar hardware.Maybe take a look at that issue think its online at high tech site too.
He is running twins. He had the smaller engine and turbos in that article.
But you can easily hit your stated rwhp goals with a forged 346, ls2 or 6.0 iron block.
I plan on hitting around 800rwhp with auto with my combo in the sig and its truly streetable and way more power than most tires can handle at even 650rwhp and around 8psi . Now add in a bigger 427 or 454 cube motor and well good luck hooking it up and please share you secret if you figure out how to.
I was going to go 427 but now happy stopped at the 408. Its all I could ask for . Now traction limited not power limited. Thats a nice place to be. I am going to be trying out eboost 2 to see how it helps hook the car up by controlling boost by rpm /gear. Course even bigger motors like a 427 or 454 have so much torque and hp off boost it makes things even harder to get traction. I can blow the nittos off easily with the 9.5 compression ,built 408 even without a pound of boost.
Of course its your build,your car and your money.
Tiago the guy in high tech performance just did a 427 build way beyond 700rwhp with similar hardware.Maybe take a look at that issue think its online at high tech site too.
He is running twins. He had the smaller engine and turbos in that article.
But you can easily hit your stated rwhp goals with a forged 346, ls2 or 6.0 iron block.
I plan on hitting around 800rwhp with auto with my combo in the sig and its truly streetable and way more power than most tires can handle at even 650rwhp and around 8psi . Now add in a bigger 427 or 454 cube motor and well good luck hooking it up and please share you secret if you figure out how to.
I was going to go 427 but now happy stopped at the 408. Its all I could ask for . Now traction limited not power limited. Thats a nice place to be. I am going to be trying out eboost 2 to see how it helps hook the car up by controlling boost by rpm /gear. Course even bigger motors like a 427 or 454 have so much torque and hp off boost it makes things even harder to get traction. I can blow the nittos off easily with the 9.5 compression ,built 408 even without a pound of boost.
Of course its your build,your car and your money.
11-26-2008, 09:32 PM
#5
Are you sure you didnt leave the 1 out of 1700 rwhp? You have a very impressive parts list for what your goals are.
If your goals are only 700rwhp, use a smaller ci engine so you can use a smaller turbo to hit your goal. Then pocket the 10-15k difference in money you were going to spend.
If your goals are only 700rwhp, use a smaller ci engine so you can use a smaller turbo to hit your goal. Then pocket the 10-15k difference in money you were going to spend.
11-26-2008, 09:41 PM
#6
Well sounds like its been covered above but I have to agree and say you are way overbuilding for 700 rwhp. A 427 or 454 with the heads/intake/tb mention above with high compression (11-11.5:1) and a good sized cam could hit 550-600 rwhp NA. A 427 or 454 built for FI would need a fairly good sized turbo to be efficient/effective. I would say minimum an 85-88mm turbo would be needed and that would out you in the 900-1000 rwhp range. I would say for 700 rwhp go with a forged ls2 (364 ci), AFR 225 heads, decent sized turbo cam, fast 92/92 intake/tb (could also use an ls6 or ls2 intake and your choice of tb for a more cost efficient setup), and then a single turbo kit running say an 80-85mm turbo. That would easily make 700 rwhp and would be much more suited for your goals. Not saying that your setup above doesnt sound amazing but may be overkill.
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11-27-2008, 02:58 AM
#8
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Well I am glad to hear that the parts I have are going to produce more then expected. I know this sounds like over kill but I also have a TNT direct port nitrous kit that I can use as well for cooling or so. As for turbos, twin 76mm or a single 85/88mm. Hey NemeSS you and you're family have a Happy Thanks giving.
11-27-2008, 08:54 AM
#9
Well I am glad to hear that the parts I have are going to produce more then expected. I know this sounds like over kill but I also have a TNT direct port nitrous kit that I can use as well for cooling or so. As for turbos, twin 76mm or a single 85/88mm. Hey NemeSS you and you're family have a Happy Thanks giving.
For that size motor I would suggest a single 91mm. That big of a motor needs to breathe.
11-27-2008, 09:19 AM
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ditto on the 91. have fun getting traction when it spools though 
for a street car, tc-76 with a 370 would be hella fun but i also overkill so i can see the desire for a 427 with a huge turbo lol
for a street car, tc-76 with a 370 would be hella fun but i also overkill so i can see the desire for a 427 with a huge turbo lol
11-28-2008, 07:59 AM
#12
I tried putting a direct port setup on my engine when I had just an incon twin turbo kit on it also. (video in my sig) I never sprayed it like that though because it is way to complicated and "busy" in the engine compartment. just stick with the turbos and if you want to spray anything, spray meth.
11-28-2008, 08:32 AM
#13
Sounds like you are planning on spending a ton of money to make what my GTO makes with mostly stock parts.
My Set Up LQ9 90K miles plus a BullsEye T-4 74mm Turbo @ 19lbs = 825RWH
My Set Up LQ9 90K miles plus a BullsEye T-4 74mm Turbo @ 19lbs = 825RWH
11-28-2008, 10:28 AM
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11-28-2008, 08:53 PM
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Big blocks and really motors over 350cid should have twins. They don't really make more power but they spool faster and they share the heat load from the motor instead of packing it all into one turbo. This makes them more efficient and more reliable, two qualities i'm sure you're interested in on a street car.
11-30-2008, 12:44 PM
#19
lmfao must be nice ! your car will be low boost like 10-12 psi on a very safe tune and still make 800 rwhp easy that's insane. but when you race a bolt on cobra at a redlight and you see brake light's the whole time. you can honeslty tell him you lost because your car make to much power. even funnier you race him agin on the interstate and spin past him you can laugh like hell.
