Boost Guys Opinion
Boost Guys Opinion I am not sure if everyone reads every forum so since I have a boosted car I thought I would post this here to get some additonal opinions.
I have a 2000 Camaro 408, Comp 220/224 581 581 114, Crane duel springs, Yellow Terra rockers non adjustable, T76 .96 housing modified STS, 3 Bar map.
The issue I am having is no matter what gear so first gear maybe about 5-6 psi boost at around 5500 rpm the car just falls on its face. I can be at full boost 18 psi 4th gear but once it hits 5500 rpm it falls on its face. It is almost like there is governor on the car. I have checked all the areas where to ensure that the rev limiters are set to 6500 but this does not feel like I am hitting the rev limiter. We all know what it feels like to hit the limiter.
We thought back pressure when I had the .81 housing on so I switched to .96 no change. Thought it might be the fuel injectors so I changed from a 57 to a 79.
I have people telling me different things so I would like you alls opinions too. Some say the cam may be a tooth advanced so the valve timing is messed up so there is a fuel brining issue and others say it is the PCM.
Unless someone tells me different I am going to try the PCM tomorrow.
Thanks in advance for the help,
Kane
I have a 2000 Camaro 408, Comp 220/224 581 581 114, Crane duel springs, Yellow Terra rockers non adjustable, T76 .96 housing modified STS, 3 Bar map.
The issue I am having is no matter what gear so first gear maybe about 5-6 psi boost at around 5500 rpm the car just falls on its face. I can be at full boost 18 psi 4th gear but once it hits 5500 rpm it falls on its face. It is almost like there is governor on the car. I have checked all the areas where to ensure that the rev limiters are set to 6500 but this does not feel like I am hitting the rev limiter. We all know what it feels like to hit the limiter.
We thought back pressure when I had the .81 housing on so I switched to .96 no change. Thought it might be the fuel injectors so I changed from a 57 to a 79.
I have people telling me different things so I would like you alls opinions too. Some say the cam may be a tooth advanced so the valve timing is messed up so there is a fuel brining issue and others say it is the PCM.
Unless someone tells me different I am going to try the PCM tomorrow.
Thanks in advance for the help,
Kane
TR6 with .25 gap. I think now looking at all my graphs with different setups but the same cam in every setup I am seeing a consisten power issue. What is a good tame turbo cam these days with like a 116 lsa? Would a Z06 cam work with a 408 our would that cam be limited too?
Here is a link to the other thread.
https://ls1tech.com/forums/generatio...rev-issue.html
Thanks,
Kane
Here is a link to the other thread.
https://ls1tech.com/forums/generatio...rev-issue.html
Thanks,
Kane
TECH Apprentice
Joined: Mar 2006
Posts: 361
Likes: 1
From: australia
ok,
firstly we know that 6 psi = 1.40 p2/p1 ratio
and 18 psi = 2.22 p2/p1 ratio
rough calculations here:
408 cubes x 5500 rpm / 3456 = 649.3 cfm
(cfm x pressure ratio ) 649.3 x 1.4 = 909.02 "turbocharged cfm"
( cfm > lbs' per minute) 909.02 x 0.0691 = 62.8 lb/min of air..
now go and look at the graph provided....
along the p2/p1 vertical axis , get to 1.4 ....
now go to the right until you get to 62-63 lb's per minute
what do you see ????
way, way off the flow chart
now the same with 18 psi... ( 2.22 p2/p2)
408 x 5500 / 3456 = 649.3
649.2 x 2.22 = 1441.2
1441.2 x 0.0691 = 99.58 lb's /min
no way the 76mm turbo will flow 99-100 lbs /min
you have your answer...
cheers
ash
claimer;
no air temperature increase included in maths
100% volumetric eff assumed for ease of example.
firstly we know that 6 psi = 1.40 p2/p1 ratio
and 18 psi = 2.22 p2/p1 ratio
rough calculations here:
408 cubes x 5500 rpm / 3456 = 649.3 cfm
(cfm x pressure ratio ) 649.3 x 1.4 = 909.02 "turbocharged cfm"
( cfm > lbs' per minute) 909.02 x 0.0691 = 62.8 lb/min of air..
now go and look at the graph provided....
along the p2/p1 vertical axis , get to 1.4 ....
now go to the right until you get to 62-63 lb's per minute
what do you see ????
way, way off the flow chart
now the same with 18 psi... ( 2.22 p2/p2)
408 x 5500 / 3456 = 649.3
649.2 x 2.22 = 1441.2
1441.2 x 0.0691 = 99.58 lb's /min
no way the 76mm turbo will flow 99-100 lbs /min
you have your answer...
cheers
ash
claimer;
no air temperature increase included in maths
100% volumetric eff assumed for ease of example.
well id first talk to your tuner but with the 408 and that 76 im sure its running out of steam. i would think that turbo is to small for a 408 and thats why at 5500 in every gears its dying. thats just a thought but i could be wrong.
But it only makes 5 or 6 psi in 1st gear would it not be able to rev past 5000-5500 and make power? The car feels and spools amaizing but no matter the gear or boost psi it is done. I think I am going to run it N/A and see how the car reacts with no boost.
Kane
Kane
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TECH Apprentice
Joined: Mar 2006
Posts: 361
Likes: 1
From: australia
not enough load on the engine in first gear,,,,,
if you put the car on a dyno, i bet the engine would be 'all over' a couple hundred rpm sooner than 5500 rpm...
right where the torque falls off....
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Yeah the spool would be amazing because of the size of the motor and size of the turbo. It could also be a load issue. I would just contact the tuner and see what they say
ok,
firstly we know that 6 psi = 1.40 p2/p1 ratio
and 18 psi = 2.22 p2/p1 ratio
rough calculations here:
408 cubes x 5500 rpm / 3456 = 649.3 cfm
(cfm x pressure ratio ) 649.3 x 1.4 = 909.02 "turbocharged cfm"
( cfm > lbs' per minute) 909.02 x 0.0691 = 62.8 lb/min of air..
now go and look at the graph provided....
along the p2/p1 vertical axis , get to 1.4 ....
now go to the right until you get to 62-63 lb's per minute
what do you see ????
way, way off the flow chart
now the same with 18 psi... ( 2.22 p2/p2)
408 x 5500 / 3456 = 649.3
649.2 x 2.22 = 1441.2
1441.2 x 0.0691 = 99.58 lb's /min
no way the 76mm turbo will flow 99-100 lbs /min
you have your answer...
cheers
ash
claimer;
no air temperature increase included in maths
100% volumetric eff assumed for ease of example.
firstly we know that 6 psi = 1.40 p2/p1 ratio
and 18 psi = 2.22 p2/p1 ratio
rough calculations here:
408 cubes x 5500 rpm / 3456 = 649.3 cfm
(cfm x pressure ratio ) 649.3 x 1.4 = 909.02 "turbocharged cfm"
( cfm > lbs' per minute) 909.02 x 0.0691 = 62.8 lb/min of air..
now go and look at the graph provided....
along the p2/p1 vertical axis , get to 1.4 ....
now go to the right until you get to 62-63 lb's per minute
what do you see ????
way, way off the flow chart
now the same with 18 psi... ( 2.22 p2/p2)
408 x 5500 / 3456 = 649.3
649.2 x 2.22 = 1441.2
1441.2 x 0.0691 = 99.58 lb's /min
no way the 76mm turbo will flow 99-100 lbs /min
you have your answer...
cheers
ash
claimer;
no air temperature increase included in maths
100% volumetric eff assumed for ease of example.
The problem is that, he dynoed, 540 corrected which was a real world 490 hp....so about 50 lbs a minute at the peak. And its a speed desity car so he ran NA (testing this) with the same problem........
The other problem is that zombie made 700 on his 76 on a 370 with the same heads. I made 656 on a 346 with a .82 housing 76. Both of those run zo6 cams. Even when they run out....the power doesnt fall off a cliff like kanes. The 370 was running 6000 at the peak and would even tapper much till 6600 or higher.
Same heads, similar cams, same exact exhuast (manifolds, y pipes etc) , same intakes, same exact intercoolers,same cold pipes, similar turbos , same afr, but this thing falls off a cliff......at 4700. It doesnt seem like 30 more cubes will decrease the peak hp over 1000 rpm and reduce peak power by 200 hp.
Kane I have an idea......ill post on the other board.....I think I might have a way for you to check the cam timing without pulling it apart. Or atleast close enough, to know weather its worth pulling apart.
TECH Apprentice
Joined: Mar 2006
Posts: 361
Likes: 1
From: australia
The problem is that, he dynoed, 540 corrected which was a real world 490 hp....so about 50 lbs a minute at the peak. And its a speed desity car so he ran NA (testing this) with the same problem........
The other problem is that zombie made 700 on his 76 on a 370 with the same heads. I made 656 on a 346 with a .82 housing 76. Both of those run zo6 cams. Even when they run out....the power doesnt fall off a cliff like kanes. The 370 was running 6000 at the peak and would even tapper much till 6600 or higher.
Same heads, similar cams, same exact exhuast (manifolds, y pipes etc) , same intakes, same exact intercoolers,same cold pipes, similar turbos , same afr, but this thing falls off a cliff......at 4700. It doesnt seem like 30 more cubes will decrease the peak hp over 1000 rpm and reduce peak power by 200 hp.
Kane I have an idea......ill post on the other board.....I think I might have a way for you to check the cam timing without pulling it apart. Or atleast close enough, to know weather its worth pulling apart.
The other problem is that zombie made 700 on his 76 on a 370 with the same heads. I made 656 on a 346 with a .82 housing 76. Both of those run zo6 cams. Even when they run out....the power doesnt fall off a cliff like kanes. The 370 was running 6000 at the peak and would even tapper much till 6600 or higher.
Same heads, similar cams, same exact exhuast (manifolds, y pipes etc) , same intakes, same exact intercoolers,same cold pipes, similar turbos , same afr, but this thing falls off a cliff......at 4700. It doesnt seem like 30 more cubes will decrease the peak hp over 1000 rpm and reduce peak power by 200 hp.
Kane I have an idea......ill post on the other board.....I think I might have a way for you to check the cam timing without pulling it apart. Or atleast close enough, to know weather its worth pulling apart.
i wonder if the turbo is out of balance?
the reason i used this as an example , is
I've dynoed a "few" engines, and when the torque falls off, the turbo is usally done, finished.
If there is more to the story here , it would be good to hear it...
It's got to be something easy, if these other cars make more power . ??
Is it a new engine ? camshaft not degreed correctly ?
the fall off in power has to be either llack of air or lack of fuel ??? correct ??
i wonder if there is a air leak somewhere ??
points to ponder....
Maybe it could be fuel, but if I recall correctly, it has a "fuel system" that includes, a reg, rails, #6 cross over....and knowing Kane probably duel pumps already.
I d bet he already monitored fp under operating conditions too ? Is that fp reg boost compensated?
Did you Kane?
Is it possible one side is being starved maybe? Have you compared plugs from one side to the other after a pull?
I d bet he already monitored fp under operating conditions too ? Is that fp reg boost compensated?
Did you Kane?
Is it possible one side is being starved maybe? Have you compared plugs from one side to the other after a pull?
Dual in tank walbros, high flow rails, -8 AN braided hose feed, -6 AN braided hose return, Adjustable fuel regulator. Fuel is rock solid AFR is right on. I did not think both threads were going to take off like this so please look at all the data on
https://ls1tech.com/forums/generatio...rev-issue.html
Picture of fuel.
http://members.***.net/kane-forum/STS%20Kit.htm
Kane
https://ls1tech.com/forums/generatio...rev-issue.html
Picture of fuel.
http://members.***.net/kane-forum/STS%20Kit.htm
Kane
Maybe it could be fuel, but if I recall correctly, it has a "fuel system" that includes, a reg, rails, #6 cross over....and knowing Kane probably duel pumps already.
I d bet he already monitored fp under operating conditions too ? Is that fp reg boost compensated?
Did you Kane?
Is it possible one side is being starved maybe? Have you compared plugs from one side to the other after a pull?
I d bet he already monitored fp under operating conditions too ? Is that fp reg boost compensated?
Did you Kane?
Is it possible one side is being starved maybe? Have you compared plugs from one side to the other after a pull?
Maybe it could be fuel, but if I recall correctly, it has a "fuel system" that includes, a reg, rails, #6 cross over....and knowing Kane probably duel pumps already.
I d bet he already monitored fp under operating conditions too ? Is that fp reg boost compensated?
Did you Kane?
Is it possible one side is being starved maybe? Have you compared plugs from one side to the other after a pull?
I d bet he already monitored fp under operating conditions too ? Is that fp reg boost compensated?
Did you Kane?
Is it possible one side is being starved maybe? Have you compared plugs from one side to the other after a pull?
Have you measured your backpressure? I am just throwing ideas out... Big engine.. smaller turbo. Could 5krpm be where you are exceeding your backpressure limit? Whats your hot and cold side piping? I see that you thought of this and went to a .96... but maybe the limit is your pipes not your turbo?