Forced Induction Superchargers | Turbochargers | Intercoolers

Turbo size for a TT 427?

Thread Tools
 
Search this Thread
 
Old 12-10-2013, 12:28 PM
  #21  
TECH Resident
Thread Starter
iTrader: (13)
 
6togo's Avatar
 
Join Date: Feb 2012
Location: Harford co. MD
Posts: 821
Likes: 0
Received 0 Likes on 0 Posts
Default

Mine is a auto 4L80e are the PTE 6766's close to the comp 6767's I think they have bigger housings available I know .96 maybe 1.08?
Old 12-10-2013, 01:49 PM
  #22  
Moderator
iTrader: (9)
 
LIL SS's Avatar
 
Join Date: Nov 2001
Location: San Jose area
Posts: 2,966
Likes: 0
Received 2 Likes on 2 Posts

Default

I just bought a set of 6768's through Jon at Huron. I believe the biggest AR is .96 which is what I went with. This is going on a 418ci motor.
Old 12-10-2013, 08:07 PM
  #23  
TECH Resident
Thread Starter
iTrader: (13)
 
6togo's Avatar
 
Join Date: Feb 2012
Location: Harford co. MD
Posts: 821
Likes: 0
Received 0 Likes on 0 Posts
Default

So i'm down to two units Comp 6767 Billet BB or 7075 billet BB a/r up to .96 i think.
I think the 67's will get me close to 1300whp if i wanted and probably spool almost instantly just dont know if i should go a bit bigger?
Old 12-10-2013, 08:13 PM
  #24  
TECH Enthusiast
iTrader: (13)
 
Orr89rocz's Avatar
 
Join Date: Nov 2005
Location: Pittsburgh PA
Posts: 665
Likes: 0
Received 0 Likes on 0 Posts

Default

I would lean 7075 as i think you will be in a better part of the map with those cubes
Old 12-11-2013, 08:59 AM
  #25  
11 Second Club
iTrader: (13)
 
venom ws7's Avatar
 
Join Date: Jul 2003
Location: EARTH
Posts: 5,967
Likes: 0
Received 1 Like on 1 Post

Default

I just received Comp twin 7275s 0.84 A/R from Jon at Huron for my 408ci Manual ZO6 I really think with stalled auto and 427ci you can go anything from 67s to 80s all depends on how fast you want the car to spool , Crazy mid range power ,and how much are RPM are you planning to go , Dig runs or Street car , Highway 150+mph runs?
I went with slightly bigger turbos hoping for a better traction with my light ZO6 Looking for 3500-3800rpm spool and shifting around 7000rpm with the right cam.
Old 12-11-2013, 03:04 PM
  #26  
TECH Resident
Thread Starter
iTrader: (13)
 
6togo's Avatar
 
Join Date: Feb 2012
Location: Harford co. MD
Posts: 821
Likes: 0
Received 0 Likes on 0 Posts
Default

Mine is mostly a street car with some 1/4 mile hops. I think the 67's will spool very fast and the 72's should be a bit lazier on the bottom. Comp said the 67's will make that power no problem and still have some left.
Old 12-11-2013, 10:55 PM
  #27  
TECH Resident
Thread Starter
iTrader: (13)
 
6togo's Avatar
 
Join Date: Feb 2012
Location: Harford co. MD
Posts: 821
Likes: 0
Received 0 Likes on 0 Posts
Default

Choices like this suck!
Old 12-12-2013, 09:53 PM
  #28  
TECH Resident
Thread Starter
iTrader: (13)
 
6togo's Avatar
 
Join Date: Feb 2012
Location: Harford co. MD
Posts: 821
Likes: 0
Received 0 Likes on 0 Posts
Default

Any more input?
Old 12-12-2013, 11:12 PM
  #29  
FormerVendor
 
qqwqeqwrqwqtq's Avatar
 
Join Date: Dec 2001
Location: WWW.SPEEDINC.COM
Posts: 2,444
Likes: 0
Received 2 Likes on 2 Posts

Default

Well there isn't anything about this that is a guess. Detail exactly what you want and their will be a pair of turbos that match that goal.

For example, GT3582R's will make 1000rwhp and make peak torque at just over 4000 rpm.

6766's will do 1300+rwhp and make peak torque around 5000rpm

7675's will do close to 2000rwhp and make peak torque around 6500rpm.

The above are just examples and would change quite a bit depending on the exact combination but still realistic trends. Keep in mind that peak torque on a turbo car will usually coincide with where it initially made peak boost and you can see that as you go up in turbo size/power potential you are shifting your power curve higher in the rpm range, sacrificing low and mid rpm power and response as a result.

Once you get up past 6766's or so, in my opinion you will need to switch to a solid roller in order to have the rpm capability to match the turbos or you will end up with a very narrow powerband. (You will need to shift it before it makes peak power)
Old 12-13-2013, 12:51 AM
  #30  
Moderator
iTrader: (9)
 
LIL SS's Avatar
 
Join Date: Nov 2001
Location: San Jose area
Posts: 2,966
Likes: 0
Received 2 Likes on 2 Posts

Default

As mentioned I went 6768's. I told John I wanted to make over 1k rwhp through a 418 with a big stalled glide / 9" and tap the 8.50 cert cage my truck has at 3, 300lbs while keeping a 7, 500 rpm shift. Most likely I will swap back to an 80e and put a 3.73 gear with a bit tighter verter, but by the looks of the 6768's I will still hit my goals if I make that change.
Old 12-13-2013, 07:03 AM
  #31  
TECH Resident
Thread Starter
iTrader: (13)
 
6togo's Avatar
 
Join Date: Feb 2012
Location: Harford co. MD
Posts: 821
Likes: 0
Received 0 Likes on 0 Posts
Default

I dont really want to spin it much past 7K and maxing out at 1300whp would be fine at what boost would it take the 6766's to make that power and what is their power curve?
Is it safe to say the Comp 6767 is very close to the same as the PTE 6766 spec wise they are almost spot on?
Old 12-13-2013, 09:40 AM
  #32  
Moderator
iTrader: (9)
 
LIL SS's Avatar
 
Join Date: Nov 2001
Location: San Jose area
Posts: 2,966
Likes: 0
Received 2 Likes on 2 Posts

Default

I think it is a bit hard to say exactly how much boost is required, but I'd guess on a well thought out 427 long block, 20-22ish psi would get you close.
Old 12-13-2013, 11:41 AM
  #33  
TECH Resident
Thread Starter
iTrader: (13)
 
6togo's Avatar
 
Join Date: Feb 2012
Location: Harford co. MD
Posts: 821
Likes: 0
Received 0 Likes on 0 Posts
Default

That would be fine so around 1kw would be around 16-18psi which was my goal but I will probably keep It down around the 10psi area on the street.
Old 12-13-2013, 12:18 PM
  #34  
TECH Enthusiast
iTrader: (13)
 
Orr89rocz's Avatar
 
Join Date: Nov 2005
Location: Pittsburgh PA
Posts: 665
Likes: 0
Received 0 Likes on 0 Posts

Default

On what fuel? My motor isnt lsx but it has cubes and good heads but its low comp and alittle loose, it took 24 psi to break 1000 thru a big stall th400. But pure 93 oct gas only. Higher comp and even better heads like 15 deg ls stuff will likely make same power on much less boost but reach a threshold on pump sooner perhaps. Depends on where that power is made and how hot iats are. 1300 is a hell of alot more and if you dont spin past 7k, you'll need alot of boost.

But dont be afraid of that just keep it cool
Old 12-13-2013, 02:28 PM
  #35  
TECH Resident
Thread Starter
iTrader: (13)
 
6togo's Avatar
 
Join Date: Feb 2012
Location: Harford co. MD
Posts: 821
Likes: 0
Received 0 Likes on 0 Posts
Default

Mostly pump gas but if I need to turn it up I can get 112 fairly local. Comp is 9.5-1 heads are ported LSX ls7 that flow very well and its getting a custom IC good to around 1500hp made by Chiseled so that should help! Should I go with the larger .96 housing with the 6767's ?
Old 12-13-2013, 02:44 PM
  #36  
TECH Junkie
iTrader: (4)
 
Gordon0652's Avatar
 
Join Date: Sep 2006
Posts: 3,188
Received 2 Likes on 2 Posts

Default

Just call these guys, ask for Jose. www.forcedinductions.com
How about two TC76s...
Old 12-13-2013, 03:51 PM
  #37  
TECH Resident
Thread Starter
iTrader: (13)
 
6togo's Avatar
 
Join Date: Feb 2012
Location: Harford co. MD
Posts: 821
Likes: 0
Received 0 Likes on 0 Posts
Default

I sent them a email not got a reply yet but 76's are probably to big size and HP wise I think they say they will support close to 2khp.
Old 12-13-2013, 04:08 PM
  #38  
TECH Enthusiast
 
Twin turbo c5's Avatar
 
Join Date: Oct 2012
Location: Arkansas
Posts: 581
Likes: 0
Received 0 Likes on 0 Posts
Default

I had friend that made 900hp to the wheels with 6266's on a 427 . It was crazy fun and spooled instantly.
Old 12-13-2013, 04:18 PM
  #39  
TECH Resident
Thread Starter
iTrader: (13)
 
6togo's Avatar
 
Join Date: Feb 2012
Location: Harford co. MD
Posts: 821
Likes: 0
Received 0 Likes on 0 Posts
Default

I'm really leaning on the side of the Comp 6767's from what I found they are almost the same specs as the 6766 PTE units and the BB units are way more reasonable.
I just have to figure out what size housing and divided or undivided!
Old 12-13-2013, 05:52 PM
  #40  
9 Second Club
 
stevieturbo's Avatar
 
Join Date: Nov 2003
Location: Norn Iron
Posts: 13,616
Received 180 Likes on 155 Posts

Default

Unless you have full tubular manifolds leading to divided collectors, then there is no benefit at all to running a divided housing. In fact, that is the only reason you'd ever want to use the divided housings.

Dont forget though, 76's are too bit, but Precision, Comp etc all make a good few units in between 67 and 76 too.
There is no lack of models to choose from !


Quick Reply: Turbo size for a TT 427?



All times are GMT -5. The time now is 08:31 AM.