Radix or STS for a 408?
Aug 9, 2005 | 11:11 PM
#31
Originally Posted by zippy
a radix for your case. solid and reliable. if you aren't out to build a race truck type 408 the radix will feed it just fine. a mild cammed 408 with small port heads and a radix will make for off idle torque that just can't be made with a turbo setup. with the weight of your avalanche and emissions being an issue i'd certainly go with the radix. the radix even works well at the track...
Aug 10, 2005 | 12:41 AM
#34
Originally Posted by F8L Z71
I don't believe a Radix can support the CFM needed to make it worthwhile on a 408. The STS could easily do so with the upgraded piping and bigger turbo. One good aspect is the lag won't be so noticable on the big motor due to the great low end power.
So out of those I would definately go STS.
Another factor is where you want the power. IMO a roots style would be a waste on a big cubed motor because traction will be limited. Why not make the motor more efficient in the midrange and top end instead.
So out of those I would definately go STS.
Another factor is where you want the power. IMO a roots style would be a waste on a big cubed motor because traction will be limited. Why not make the motor more efficient in the midrange and top end instead.
I would look into a livernoise, W2W, or ctmotorsports kit if I was gonna do it right. who wouldnt want to make parish type power of at least somewhere close to it.
Aug 10, 2005 | 01:15 AM
#35
Thread Starter
TECH Veteran
Joined: Mar 2004
Posts: 4,632
Likes: 2
From: Sun Diego
Wow, interesting....it almost seems civilized in here. I'm not sure I'm on the right board. 
In the AV I really have no problems with traction.....at 5800 lbs (6050 lbs with me in it) with my stock 5-link and 25" of rubber in the back, I grip pretty well, thank you very much. Once I get up to NorCal I will be getting some custom rear coils that are 1" lower and made to hook. At that point the issue will be the 10-bolt, not traction.
As far as a centrifugal blower, doesn't that give you the worst of both worlds? The parasitic loss of a belt-driven SC, together with the lag of a turbo, right? Why would I want to do that?
Ideally I'd get a low compression 408 and that 3.3L manifold-mounted Whipple from those guys down under at Starr. But since I'm not made of money, and seeing as they're charging North of $10K just for the 2.3L version, I don't even want to know the price of it's Big Brother.
So until such time that I land that big contract (and move away from the CARB cops) I think these are my choices - STS or Radix.
Zippy presents an interesting argument for a Radixed-408....don't overcam it, cam it just right. It would be nice to have power everywhere - the low-end, all-over torque that a 408 would provide (with a 220/224 or so), together with the low-end, all-over torque of a Radix. That does sound like a dreamy daily driver.
But the turbo is also appealing, for different reasons. Nothing feels quite like a V-8 turbo. Heck, even a 4-cyl or 6-cyl turbo is pretty amazing to drive. Not to mention the turbo would likely be a little quieter, and get a little better gas mileage. Hmm....
In the AV I really have no problems with traction.....at 5800 lbs (6050 lbs with me in it) with my stock 5-link and 25" of rubber in the back, I grip pretty well, thank you very much. Once I get up to NorCal I will be getting some custom rear coils that are 1" lower and made to hook. At that point the issue will be the 10-bolt, not traction.
As far as a centrifugal blower, doesn't that give you the worst of both worlds? The parasitic loss of a belt-driven SC, together with the lag of a turbo, right? Why would I want to do that?
Ideally I'd get a low compression 408 and that 3.3L manifold-mounted Whipple from those guys down under at Starr. But since I'm not made of money, and seeing as they're charging North of $10K just for the 2.3L version, I don't even want to know the price of it's Big Brother.
So until such time that I land that big contract (and move away from the CARB cops) I think these are my choices - STS or Radix.
Zippy presents an interesting argument for a Radixed-408....don't overcam it, cam it just right. It would be nice to have power everywhere - the low-end, all-over torque that a 408 would provide (with a 220/224 or so), together with the low-end, all-over torque of a Radix. That does sound like a dreamy daily driver.
But the turbo is also appealing, for different reasons. Nothing feels quite like a V-8 turbo. Heck, even a 4-cyl or 6-cyl turbo is pretty amazing to drive. Not to mention the turbo would likely be a little quieter, and get a little better gas mileage. Hmm....
Aug 10, 2005 | 05:49 AM
#36
TECH Resident
Joined: Nov 2001
Posts: 880
Likes: 1
From: Twin Cities
Originally Posted by vanillagorilla
That turbo sounds a little small for a 408, if you're looking for best overall performance.
Anyway, what about a nice 3.3L intercooled Whipple.
Anyway, what about a nice 3.3L intercooled Whipple.
You were joking right..
Aug 10, 2005 | 09:59 AM
#37
12 Second Truck Club
Joined: Feb 2002
Posts: 5,575
Likes: 0
From: Sacramento, CA
I like the keyboard jockey comment...
I've had a centrifugal, I've been N/A, then Nitrous, now turbo'd and I've seen plenty of Radix combos at the track. I'm not over impressed till you start spraying them. I've also seen just as many problems with the kit as I have any other. IMO figure out where you want the power and what kind of feel you're looking for and go from there. At least you have CARB legal choices now.
I've had a centrifugal, I've been N/A, then Nitrous, now turbo'd and I've seen plenty of Radix combos at the track. I'm not over impressed till you start spraying them. I've also seen just as many problems with the kit as I have any other. IMO figure out where you want the power and what kind of feel you're looking for and go from there. At least you have CARB legal choices now.
Aug 10, 2005 | 12:23 PM
#38
Staging Lane
Joined: Jun 2004
Posts: 88
Likes: 0
From: Rocklin
kevin, the hell with emissions lets worry about that in about 4 years 
I have never felt a radix before (rode in a L with upgraded pulleys, that was nice), but i think you will like the 408 with the STS. Off the line im sure a radix may pull on you but when that GT70 kicks in, HOLD ON!!!! Hell if you were closer i'd take you for a ride, it would help your decision a little more Anyway you decide the 408 will be nice
I have never felt a radix before (rode in a L with upgraded pulleys, that was nice), but i think you will like the 408 with the STS. Off the line im sure a radix may pull on you but when that GT70 kicks in, HOLD ON!!!! Hell if you were closer i'd take you for a ride, it would help your decision a little more
Anyway you decide the 408 will be nice
Aug 10, 2005 | 12:33 PM
#39
Thread Starter
TECH Veteran
Joined: Mar 2004
Posts: 4,632
Likes: 2
From: Sun Diego
Originally Posted by haynSS
kevin, the hell with emissions lets worry about that in about 4 years
I have never felt a radix before (rode in a L with upgraded pulleys, that was nice), but i think you will like the 408 with the STS. Off the line im sure a radix may pull on you but when that GT70 kicks in, HOLD ON!!!! Hell if you were closer i'd take you for a ride, it would help your decision a little more Anyway you decide the 408 will be nice
I have never felt a radix before (rode in a L with upgraded pulleys, that was nice), but i think you will like the 408 with the STS. Off the line im sure a radix may pull on you but when that GT70 kicks in, HOLD ON!!!! Hell if you were closer i'd take you for a ride, it would help your decision a little more
Anyway you decide the 408 will be nice
Aug 10, 2005 | 12:38 PM
#40
12 Second Truck Club
Joined: Feb 2002
Posts: 5,575
Likes: 0
From: Sacramento, CA
His truck wont be ready by then. Hell that thing is never going to run right again. :p
Rocklin is 5min up the road from my house if you wanna ride in a real STS truck... Wait, mine wont be finished by then either.
Rocklin is 5min up the road from my house if you wanna ride in a real STS truck... Wait, mine wont be finished by then either.