Best intake manifold for turbo kit?
Thread Starter
Joined: Nov 2001
Posts: 8,246
Likes: 34
From: Victoria, TX
Best intake manifold for turbo kit? I have a few choices right now. Currently, I'm running an LS6 intake with stock TB for my upcoming turbo kit. I plan on making around 800 rwhp on a low compression forged 346. On NA motors, I've picked up a solid 28-30 rwhp by going from an LS6 intake to a FAST 90 with porting by Tony Mamo. My plans were to run another Mamofied FAST in my turbo setup, but some sharp people on this board have stated that under boost the LS6 intake is better (at the same boost level).
I'm not understanding how that could be so maybe someone could explain it to me. If a ported FAST 90/90 gives me 30 rwhp on a naturally aspirated 346, why wouldn't it give me at least that if not more under boost? When I go from the LS6 intake to the ported FAST, my pressure drop is less at WOT when running NA. I pull 94 kPa at WOT with an LS6 intake and stock TB, but only 98 kPa with the ported FAST. Less restriction.
Wouldn't there be less pressure drop with a ported FAST than an LS6 intake? What about an LS2 intake. On a naturally aspirated motor, it's even worse than the LS6 intake, but some people in the know claim it's even better than the LS6 intake under boost. Totally contradicts what happens NA. Please show me the light.
I'm not understanding how that could be so maybe someone could explain it to me. If a ported FAST 90/90 gives me 30 rwhp on a naturally aspirated 346, why wouldn't it give me at least that if not more under boost? When I go from the LS6 intake to the ported FAST, my pressure drop is less at WOT when running NA. I pull 94 kPa at WOT with an LS6 intake and stock TB, but only 98 kPa with the ported FAST. Less restriction.
Wouldn't there be less pressure drop with a ported FAST than an LS6 intake? What about an LS2 intake. On a naturally aspirated motor, it's even worse than the LS6 intake, but some people in the know claim it's even better than the LS6 intake under boost. Totally contradicts what happens NA. Please show me the light.
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
8 sec potential, 12 sec slip
iTrader: (50)
Joined: Apr 2002
Posts: 4,092
Likes: 2
From: Savannah, GA
As far as better flow, the advantage would be minimum because of the "forced" part of forced induction. Your turbo(s) (or SC, whatever) will flow a certain amount of air into the engine regardless of how 'easily' the intake manifold allows it to go in. The mass flow rate of air ultimately going into all the cylinders will be equal to the mass flow rate your turbo pushes out. Now what will happen though is that the boost will go up with an unported manifold (or down with a ported version- however you want to look at it), but the same amount of air will get into the cylinder either way. Think of it kind of like a garden hose flowing into a bucket. Unrestricted, it flows out easily and if you leave the hose there in the bucket for say 2 minutes, it fills the bucket up at a relatively low pressure in the hose. Now pretend you put your thumb half way over the hose- the pressure definitely goes up, but that same bucket will still be full in the same 2 minutes, it just was under more pressure to flow the same amount. I hope this is making sense here. The same applies running ported heads. Except ported heads have an advantage in that the exhaust can be ported which will allow the air to escape better. The turbo forces the same amount of air in (in theory anyways) regardless of the 'ease' in which it happens, but you need all the help you can get to get the spent exhaust gases out.
Now having explained that, I believe the FAST intake manifold is also physically weaker than the LS6 manifold, and can blow apart under boost.
Now having explained that, I believe the FAST intake manifold is also physically weaker than the LS6 manifold, and can blow apart under boost.
ChevyChad, nice write up
. I know several FI guys running a FAST intake, they seem to be doing fine. The only bad thing I've heard about the FAST is the fact that they are a two piece design and come apart under high boost. (Where this exactly is I have no clue) Then again I've always gone by the rule of using a LS6 for security and also the ability to bump up the boost and not worry about it going to chit.
I'm sure a few others in here will chime in and give there thougths as well.
. I know several FI guys running a FAST intake, they seem to be doing fine. The only bad thing I've heard about the FAST is the fact that they are a two piece design and come apart under high boost. (Where this exactly is I have no clue) Then again I've always gone by the rule of using a LS6 for security and also the ability to bump up the boost and not worry about it going to chit.I'm sure a few others in here will chime in and give there thougths as well.
would you agree that a single plane intake such as Vic. Jr. with a cast elbow plenum such as the ones used by racers used on FI motors would be the better selection, for a moderate to high psi, street/track application?
in theory this type of manifold would be the one with the least amount of restriction compared to the oem and FAST crossover runner type plenums.
assuming a proper cam profile, and turbocharger(s) selection would be used.
this type of manifold would yield the greatest overall results for even a street type car.
imo, this is the type of manifold selection i would choose for my vehicle.
what is your opinion of this manifold, Pat?
Los
in theory this type of manifold would be the one with the least amount of restriction compared to the oem and FAST crossover runner type plenums.
assuming a proper cam profile, and turbocharger(s) selection would be used.
this type of manifold would yield the greatest overall results for even a street type car.
imo, this is the type of manifold selection i would choose for my vehicle.
what is your opinion of this manifold, Pat?
Los
As far as better flow, the advantage would be minimum because of the "forced" part of forced induction. Your turbo(s) (or SC, whatever) will flow a certain amount of air into the engine regardless of how 'easily' the intake manifold allows it to go in. The mass flow rate of air ultimately going into all the cylinders will be equal to the mass flow rate your turbo pushes out. Now what will happen though is that the boost will go up with an unported manifold (or down with a ported version- however you want to look at it), but the same amount of air will get into the cylinder either way. Think of it kind of like a garden hose flowing into a bucket. Unrestricted, it flows out easily and if you leave the hose there in the bucket for say 2 minutes, it fills the bucket up at a relatively low pressure in the hose. Now pretend you put your thumb half way over the hose- the pressure definitely goes up, but that same bucket will still be full in the same 2 minutes, it just was under more pressure to flow the same amount. I hope this is making sense here. The same applies running ported heads. Except ported heads have an advantage in that the exhaust can be ported which will allow the air to escape better. The turbo forces the same amount of air in (in theory anyways) regardless of the 'ease' in which it happens, but you need all the help you can get to get the spent exhaust gases out.
Now having explained that, I believe the FAST intake manifold is also physically weaker than the LS6 manifold, and can blow apart under boost.
Now having explained that, I believe the FAST intake manifold is also physically weaker than the LS6 manifold, and can blow apart under boost.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
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
The advantage comes when you turn the fast intake up to 16psi and see the gain over the LS6 at the same boost level. The only reason people don't like the fast on forced induction setups is that some people have had them fail.
8 sec potential, 12 sec slip
iTrader: (50)
Joined: Apr 2002
Posts: 4,092
Likes: 2
From: Savannah, GA
Thats awesome! I don't know what pressure specifically is the breaking point for a FAST, but its obviously good up to at least 14psi And 14psi on a FAST would most definitely be more on an LS6 (15#? 16#?) I don't know...
But there is another thing to factor in also. Say a FAST is good up to 20psi for example. Now the same amount of air a FAST will flow at 20# would be equivalent to maybe 22# thru an LS6 lets just say for arguments sake. If the breaking point of the FAST is 20, and the breaking point of an LS6 is 22 (we know its not, but just for demonstration here), there is no advantage strength-wise anyways to use the LS6 over the FAST... Interesting to think about.
But as stated a few posts ago, if you are at the power level of flowing enough air to break a FAST or LS6, you'd probably want to take advantage of a single plane intake's better distribution.
I don't know what pressure specifically is the breaking point for a FAST, but its obviously good up to at least 14psi And 14psi on a FAST would most definitely be more on an LS6 (15#? 16#?) I don't know... But there is another thing to factor in also. Say a FAST is good up to 20psi for example. Now the same amount of air a FAST will flow at 20# would be equivalent to maybe 22# thru an LS6 lets just say for arguments sake. If the breaking point of the FAST is 20, and the breaking point of an LS6 is 22 (we know its not, but just for demonstration here), there is no advantage strength-wise anyways to use the LS6 over the FAST... Interesting to think about.
But as stated a few posts ago, if you are at the power level of flowing enough air to break a FAST or LS6, you'd probably want to take advantage of a single plane intake's better distribution.
I've heard it both ways. I'm aiming for around 650-700rwhp with a D1SC next season (maybe more...depends what I decide to do for a cam...maybe you could spec one out for me, I really liked the 224/228 cam you came up with ), and I'll be selling my FAST intake to go back to an LS6. Main reason is the $550-600 I make going back to an LS6 will pay for my 8-rib belt setup. If I had the money, I'd keep the FAST, but I'm trying to keep costs down by getting rid of whatever parts from the H/C setup that won't benefit me the most.
Kinda looking at it like....okay...I've got $600 to spend, am I better off going with an 8-rib belt setup, or a FAST90? Considering I'll make far more power with the 8-rib/LS6 than the 6-rib/FAST (not to mention the fact that I need to buy a pulley setup anyways since I don't have a full kit), I'm going the 8-rib/LS6 combo.
), and I'll be selling my FAST intake to go back to an LS6. Main reason is the $550-600 I make going back to an LS6 will pay for my 8-rib belt setup. If I had the money, I'd keep the FAST, but I'm trying to keep costs down by getting rid of whatever parts from the H/C setup that won't benefit me the most.Kinda looking at it like....okay...I've got $600 to spend, am I better off going with an 8-rib belt setup, or a FAST90? Considering I'll make far more power with the 8-rib/LS6 than the 6-rib/FAST (not to mention the fact that I need to buy a pulley setup anyways since I don't have a full kit), I'm going the 8-rib/LS6 combo.
Patrick some had issues with the fast leaking under boost I have herd of people having failers, but have never witnessed that, and some have reported gains and some haven't, and the Victor JR with the 90 is not neccesary and has it's downfalls its not the end all for FI for sure I made great power with the LS6 and won't be changing on the TT car I will probably be changing the procharger car to an LS6 probably, but since you have an LS6 you could test it and if you don't meet your goal you could try one of the others like a Ported Fast etc... Good luck!
Jeff
Jeff
Went with an LS6, a FAST is a lot of extra money for not a whole lot of gain on an FI setup. Best off putting the money into something else for the car or even just in your bank account.
Thread Starter
Joined: Nov 2001
Posts: 8,246
Likes: 34
From: Victoria, TX
All this still doesn't really explain why a 30 rwhp gain with a ported FAST wouldn't be worth that or more with forced induction. The power gain is from reduced pressure drop and reduced induction restriction. Why wouldn't the power gains over an LS6 translate when running under Boost?
Stated another way:
Would everybody agree that the ported FAST would make the same power as the LS6 intake but with less boost? If so, then wouldn't the ported FAST 90 make more power with the SAME boost?
Stated another way:
Would everybody agree that the ported FAST would make the same power as the LS6 intake but with less boost? If so, then wouldn't the ported FAST 90 make more power with the SAME boost?
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
All this still doesn't really explain why a 30 rwhp gain with a ported FAST wouldn't be worth that or more with forced induction. The power gain is from reduced pressure drop and reduced induction restriction. Why wouldn't the power gains over an LS6 translate when running under Boost?
Stated another way:
Would everybody agree that the ported FAST would make the same power as the LS6 intake but with less boost? If so, then wouldn't the ported FAST 90 make more power with the SAME boost?
Stated another way:
Would everybody agree that the ported FAST would make the same power as the LS6 intake but with less boost? If so, then wouldn't the ported FAST 90 make more power with the SAME boost?