Help with 408 turbo selection
Thread Starter
High on diesel fumes
iTrader: (70)
Joined: Mar 2005
Posts: 12,333
Likes: 0
From: Phoenix, AZ
Help with 408 turbo selection Looking for some opinions on turbo selection for my 408, mainly compressor size and a/r housing. I doubt I'll spin the motor up any higher than 6300 RPM. I think my cam runs out of steam right around there.
If I go with a turbonetics unit, I'm thinking the Super-T T76. Their matrix recommends the q-trim .96 a/r housing. About what RPM will this spool at?
I called a distributor for Garrett and asked his recommendation, and he told some that a GT42 would probably be about right. He said that a 1.15 a/r might be ok, but that it might generate a lot of heat if I'm hard on the gas towing up a long hill or something (which I will do). He recommended a 1.28 a/r housing, but said that it would probably spool around the 2500-2800 RPM range.
I'm confused as to why the turbonetics unit has so much smaller a/r housing. I'd like to see a little bit lower spool RPM than the 2500-2800 that the 1.28 Garrett a/r offers (especially since I am severely lacking in the low-end torque department due to my 7.0:1 DCR), but I'm concerned about heat and exhaust pressure like the guy said with the 1.15.
What do you guys recommend? Am I on the right track?
If I go with a turbonetics unit, I'm thinking the Super-T T76. Their matrix recommends the q-trim .96 a/r housing. About what RPM will this spool at?
I called a distributor for Garrett and asked his recommendation, and he told some that a GT42 would probably be about right. He said that a 1.15 a/r might be ok, but that it might generate a lot of heat if I'm hard on the gas towing up a long hill or something (which I will do). He recommended a 1.28 a/r housing, but said that it would probably spool around the 2500-2800 RPM range.
I'm confused as to why the turbonetics unit has so much smaller a/r housing. I'd like to see a little bit lower spool RPM than the 2500-2800 that the 1.28 Garrett a/r offers (especially since I am severely lacking in the low-end torque department due to my 7.0:1 DCR), but I'm concerned about heat and exhaust pressure like the guy said with the 1.15.
What do you guys recommend? Am I on the right track?
Thread Starter
High on diesel fumes
iTrader: (70)
Joined: Mar 2005
Posts: 12,333
Likes: 0
From: Phoenix, AZ
Towing is not the main goal. I want to put the truck in the 10's, but it's still going to be my daily driver. Mostly I want it to be fast and fun to drive, but it will see towing duty as a rig for a 6000 lb boat.
mine has a ITS 80mm turbo on it right now and today made 615/615 but the tuning isn't done yet. should be upwards of 650-700rwhp when done. that too is on a 408.
have you contacted Jose at forcedinductions? That's who I'd call if I were doing it again. Also, I missed it, are you going T4 or T6?
have you contacted Jose at forcedinductions? That's who I'd call if I were doing it again. Also, I missed it, are you going T4 or T6?
Thread Starter
High on diesel fumes
iTrader: (70)
Joined: Mar 2005
Posts: 12,333
Likes: 0
From: Phoenix, AZ
I've been reading your nightmare threads about your truck - congrats on it finally running!
I'll call Jose tomorrow...I've had quite a few people recommend talking to him.
T4 or T6 - I know those are flange sizes, but that's about it
Most of what I have seen is based on the T4 flange, but I haven't learned enough yet to know what difference it makes. Maybe that will be tomorrow's goal 
I'll call Jose tomorrow...I've had quite a few people recommend talking to him.
T4 or T6 - I know those are flange sizes, but that's about it
Most of what I have seen is based on the T4 flange, but I haven't learned enough yet to know what difference it makes. Maybe that will be tomorrow's goal 
TECH Addict
Joined: Jul 2002
Posts: 2,906
Likes: 0
From: Somewhere I Belong
Parish8 was running low 10's with his PT88 @ 16psi 'n 100shot assistance 
http://www.precisionturbo.net
Give him a call buddy
peace
http://www.precisionturbo.net
Give him a call buddy
peace
The t-6 flange is commonly known as the "thumper" flange, it is usually for all-out apps, the opening is much larger, you can get a blanket for t-6 flange turbos either. A t-4 flanged turbo will be easier to package and many more options.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo Thread Starter
High on diesel fumes
iTrader: (70)
Joined: Mar 2005
Posts: 12,333
Likes: 0
From: Phoenix, AZ
Originally Posted by 1slow01Z71
meant to say you CANT get a turbo blanket for the t-6 flange turbos
Originally Posted by DanaliHD
mine has a ITS 80mm turbo on it right now and today made 615/615 but the tuning isn't done yet. should be upwards of 650-700rwhp when done. that too is on a 408.
have you contacted Jose at forcedinductions? That's who I'd call if I were doing it again. Also, I missed it, are you going T4 or T6?
have you contacted Jose at forcedinductions? That's who I'd call if I were doing it again. Also, I missed it, are you going T4 or T6?
. When I was doing my turbo research, everyone else I spoke to were damn idiots 
. No one could tell me what my back pressure and intake temps were going to be like and couldn't give me at least where on the compressor map I would fall. All they could quote me is catalog peformance 
. Jose and Jason answered everything.....by far the most knowledgeble. Also they sell turbos from EVERY manufacture, so their opinion is NOT biased on what they can only sell. Alot of people still don't get that on these message boards. If a dealer sells only Garrett, well he isn't going to tell you if the turbonetics is better.....lol, or if a borg warner is better . .
Originally Posted by 1slow01Z71
The t-6 flange is commonly known as the "thumper" flange, it is usually for all-out apps, the opening is much larger, you can get a blanket for t-6 flange turbos either. A t-4 flanged turbo will be easier to package and many more options.
That may be true but a T4 flanged unit on a 408ci motor is going to have alot of back pressure with that flange........
I have the S88 wich is a T6 flanged 88mm turbo with a 1.26 ar
sppols just fine with my 370..... i would imagine ven better with 38ci more...
Remember.. there a reason Parish went bigger..... she was just about out of steam..............
Kyle
Originally Posted by NA$TY-TA
That may be true but a T4 flanged unit on a 408ci motor is going to have alot of back pressure with that flange........
I have the S88 wich is a T6 flanged 88mm turbo with a 1.26 ar
sppols just fine with my 370..... i would imagine ven better with 38ci more...
Remember.. there a reason Parish went bigger..... she was just about out of steam..............
Kyle
I have the S88 wich is a T6 flanged 88mm turbo with a 1.26 ar
sppols just fine with my 370..... i would imagine ven better with 38ci more...
Remember.. there a reason Parish went bigger..... she was just about out of steam..............
Kyle
