Turbo Cam Help Please!!!
05-29-2009, 03:46 PM
#61
I don't know what is causing your issues with making power N/A, but I do see several issues once you go turbo.
1. You said the converter already has lots of slip, adding a turbo is going to make this many times worse.
2. the 918 springs are known to float in boosted apps, especially with high lift cams.
3. Turbo is too small to reach your goals. A .81 a/r T76 feeding a 408 is just too small to make 800 rwhp, especially as a rear mount where you lose a lot of efficiency and have high back pressure.
4. your compressions is really going to limit you on the street unless you run race gas or lots of meth all the time.
1. You said the converter already has lots of slip, adding a turbo is going to make this many times worse.
2. the 918 springs are known to float in boosted apps, especially with high lift cams.
3. Turbo is too small to reach your goals. A .81 a/r T76 feeding a 408 is just too small to make 800 rwhp, especially as a rear mount where you lose a lot of efficiency and have high back pressure.
4. your compressions is really going to limit you on the street unless you run race gas or lots of meth all the time.
05-29-2009, 05:02 PM
#63
I do plan on building a 4l80e for it next, so the converter will be new then, not sure what size to go with then though.
I wish I had 918 springs, actually they are the 26918 wich are the behieve style, which I think are not as good as the 918's, I am not apposed to changing springs with the cam.
Yes you are right about the turbo. I can up size the housing, but I dought that is going to fix the backpressure. There is a long story behind the turbo, which I will wait to get into. There might be some nasty things said in the future if I am not able to resolve the turbo purchase peacefully. At this time, I have not heard what I should hear on that. It is a very sour subject that I feal like I got screwed in.
Yes you are right about the compresion too. I do plan on using meth, and it is more of a trailer queen, but I do like to go out on the street and tangle some. I do plan on running race fuel in it when I go to play on the street and at the track.
Oh the turbo, that stinking turbo!!!!! I am compiling my emails, pm, and other corispondence this weeking to try and politly convince the sellers to take it back and credit me so I can purchase a T-88 from them. Basicaly they sized this thing to work with a 427 LSX that I was going to build. I was not able to build the 427 and had to go with a 408. Now for some reason it won't work behind the 408. Funny how it was good enough for the 427 but not the 408. HMMMM.... I will not name names unless they continue to give me the run around. I pray they will see their mistake and nothing will need to said namewise in the public.
I wish I had 918 springs, actually they are the 26918 wich are the behieve style, which I think are not as good as the 918's, I am not apposed to changing springs with the cam.
Yes you are right about the turbo. I can up size the housing, but I dought that is going to fix the backpressure. There is a long story behind the turbo, which I will wait to get into. There might be some nasty things said in the future if I am not able to resolve the turbo purchase peacefully. At this time, I have not heard what I should hear on that. It is a very sour subject that I feal like I got screwed in.
Yes you are right about the compresion too. I do plan on using meth, and it is more of a trailer queen, but I do like to go out on the street and tangle some. I do plan on running race fuel in it when I go to play on the street and at the track.
Oh the turbo, that stinking turbo!!!!! I am compiling my emails, pm, and other corispondence this weeking to try and politly convince the sellers to take it back and credit me so I can purchase a T-88 from them. Basicaly they sized this thing to work with a 427 LSX that I was going to build. I was not able to build the 427 and had to go with a 408. Now for some reason it won't work behind the 408. Funny how it was good enough for the 427 but not the 408. HMMMM.... I will not name names unless they continue to give me the run around. I pray they will see their mistake and nothing will need to said namewise in the public.
05-29-2009, 07:40 PM
#66
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Texas WS6,
I am no expert or engine builder, but i have some thoughts here. First off, i would sort out whats going on with your engine before you go installing the turbo. You have a problem(s) with your motor and something isnt working right. You need to sort this issue out before you go compounding the problem by adding more complexity to the motor\system.
If i were you, this is what i would do.
STEP 1.... i would take off that intake manifold and elbow. Install a L76 intake that normally goes with the L92 heads. If you dont have this intake, see if someone near you has one that will let you borrow it. Retune the car and see what happens. If the car still runs like a dog, then you know the intake\elbow combo isnt whats screwing up the works.
STEP 2. If the car runs better due to the swap, then find a dyno and see what is going on with the power-band, where it kicks in, and see what the power curve looks like.
If the intake swap didnt improve anything and the car is still a dog, then you have eliminated the intake\elbow as a problem, and you move on to the cam. Swap the cam out, tune, and test.
Get things running properly before you go adding a turbo. Your motor, with the auto, etc, should be at least 450 rwhp.
I am no expert or engine builder, but i have some thoughts here. First off, i would sort out whats going on with your engine before you go installing the turbo. You have a problem(s) with your motor and something isnt working right. You need to sort this issue out before you go compounding the problem by adding more complexity to the motor\system.
If i were you, this is what i would do.
STEP 1.... i would take off that intake manifold and elbow. Install a L76 intake that normally goes with the L92 heads. If you dont have this intake, see if someone near you has one that will let you borrow it. Retune the car and see what happens. If the car still runs like a dog, then you know the intake\elbow combo isnt whats screwing up the works.
STEP 2. If the car runs better due to the swap, then find a dyno and see what is going on with the power-band, where it kicks in, and see what the power curve looks like.
If the intake swap didnt improve anything and the car is still a dog, then you have eliminated the intake\elbow as a problem, and you move on to the cam. Swap the cam out, tune, and test.
Get things running properly before you go adding a turbo. Your motor, with the auto, etc, should be at least 450 rwhp.
05-30-2009, 01:14 AM
#67
I do have someone whom might let me test with his sheet metal elbow, but I do not know anyone to borrow a L92 intake from. If I find one cheap enough I would probably purchase it to test.
I have to pull the engine in order to weld on a turbo oil return port to it (man I wish I would have went ahead and done that 2 months ago while I still had the engine on the stand
). I am going to inspect the entire bottom end at that time. I am also going to borescope the engine at that time. Something else I am going to do is find TDC and mark it so I can verify my timing is what the datalogger sayd it is. I do not expect to find any issues in the bottom end, nor do I expect to find any issues in the cylinders, but I want to look seeing as how I did not put this one together. This is the first engine I did not build myself so looking in it after 200 miles and say 15 passes will give me comfort. If I do not find any causes of the power loss after that then I will know it has to be one of or a combo of cam, intake elbow, or me (tuning). Well I guess it could still be in the transmittion. I bet its the combination, cam needs more compression NA then the engine has, and the elbow is probably making it even worse. I am realy thinking once I get a good turbo cam and finish the turbo it will come alive, well at least to 5000 or 5500 rpm. There realy can not be much of anything else left to cause this. I know the cylinders are sealing good. This thing has zero blowby. Something most LS1's have. The compression readings are right were they should be. The cam is timed exactly zero. It just has to be the cam, compression ratio, elbow combo that is out of wack.
So that brings me back to the original question. What cam should I go with? I am thinking of a reverse split pattern. Something like 242/230 on a 115 or 116 with about .600 lift.
What do you think?
I have to pull the engine in order to weld on a turbo oil return port to it (man I wish I would have went ahead and done that 2 months ago while I still had the engine on the stand
). I am going to inspect the entire bottom end at that time. I am also going to borescope the engine at that time. Something else I am going to do is find TDC and mark it so I can verify my timing is what the datalogger sayd it is. I do not expect to find any issues in the bottom end, nor do I expect to find any issues in the cylinders, but I want to look seeing as how I did not put this one together. This is the first engine I did not build myself so looking in it after 200 miles and say 15 passes will give me comfort. If I do not find any causes of the power loss after that then I will know it has to be one of or a combo of cam, intake elbow, or me (tuning). Well I guess it could still be in the transmittion. I bet its the combination, cam needs more compression NA then the engine has, and the elbow is probably making it even worse. I am realy thinking once I get a good turbo cam and finish the turbo it will come alive, well at least to 5000 or 5500 rpm. There realy can not be much of anything else left to cause this. I know the cylinders are sealing good. This thing has zero blowby. Something most LS1's have. The compression readings are right were they should be. The cam is timed exactly zero. It just has to be the cam, compression ratio, elbow combo that is out of wack. So that brings me back to the original question. What cam should I go with? I am thinking of a reverse split pattern. Something like 242/230 on a 115 or 116 with about .600 lift.
What do you think?
05-30-2009, 01:31 AM
#68
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I do have someone whom might let me test with his sheet metal elbow, but I do not know anyone to borrow a L92 intake from. If I find one cheap enough I would probably purchase it to test.
I have to pull the engine in order to weld on a turbo oil return port to it (man I wish I would have went ahead and done that 2 months ago while I still had the engine on the stand). I am going to inspect the entire bottom end at that time. I am also going to borescope the engine at that time. Something else I am going to do is find TDC and mark it so I can verify my timing is what the datalogger sayd it is. I do not expect to find any issues in the bottom end, nor do I expect to find any issues in the cylinders, but I want to look seeing as how I did not put this one together. This is the first engine I did not build myself so looking in it after 200 miles and say 15 passes will give me comfort. If I do not find any causes of the power loss after that then I will know it has to be one of or a combo of cam, intake elbow, or me (tuning). Well I guess it could still be in the transmittion. I bet its the combination, cam needs more compression NA then the engine has, and the elbow is probably making it even worse. I am realy thinking once I get a good turbo cam and finish the turbo it will come alive, well at least to 5000 or 5500 rpm. There realy can not be much of anything else left to cause this. I know the cylinders are sealing good. This thing has zero blowby. Something most LS1's have. The compression readings are right were they should be. The cam is timed exactly zero. It just has to be the cam, compression ratio, elbow combo that is out of wack.
So that brings me back to the original question. What cam should I go with? I am thinking of a reverse split pattern. Something like 242/230 on a 115 or 116 with about .600 lift.
What do you think?
I have to pull the engine in order to weld on a turbo oil return port to it (man I wish I would have went ahead and done that 2 months ago while I still had the engine on the stand
). I am going to inspect the entire bottom end at that time. I am also going to borescope the engine at that time. Something else I am going to do is find TDC and mark it so I can verify my timing is what the datalogger sayd it is. I do not expect to find any issues in the bottom end, nor do I expect to find any issues in the cylinders, but I want to look seeing as how I did not put this one together. This is the first engine I did not build myself so looking in it after 200 miles and say 15 passes will give me comfort. If I do not find any causes of the power loss after that then I will know it has to be one of or a combo of cam, intake elbow, or me (tuning). Well I guess it could still be in the transmittion. I bet its the combination, cam needs more compression NA then the engine has, and the elbow is probably making it even worse. I am realy thinking once I get a good turbo cam and finish the turbo it will come alive, well at least to 5000 or 5500 rpm. There realy can not be much of anything else left to cause this. I know the cylinders are sealing good. This thing has zero blowby. Something most LS1's have. The compression readings are right were they should be. The cam is timed exactly zero. It just has to be the cam, compression ratio, elbow combo that is out of wack. So that brings me back to the original question. What cam should I go with? I am thinking of a reverse split pattern. Something like 242/230 on a 115 or 116 with about .600 lift.
What do you think?
If you have checked everything and there are no problems (leaks, rings, compressions, etc), it is certainly either the cam of the intake manifold. I am assuming you are sure the heads arent Fooked up. Anyway, for a new cam, please go with EDC at flowtech inductions. YOu will get a cam that does exactly what you want, meaning power comes in when you want it, amount of lope, how often you change springs, matches your whole setup, etc. He will either line up lobes that meet your goals, or he will make new ones that do what you want. The price is the same as every other cam company\maker, so why not do it right?
Just so you know, i have no affiliation with flowtech or anything, i dont even know the man. I am going by the fact that everyone who has him do their cam is happy, they get exactly what they want. Some people just know what they are doing, and he is one. But dont take my word for it, do a search on either "EDC" "ED Curtis", or "flowtech" and look at how many times he is recommended\praised.
good luck buddy.
05-30-2009, 08:26 AM
#69
http://www.theturboforums.com/smf/in...topic=124912.0
It has 3/1 backpressure and he shifts it at 5000 rpm.
If you put a 242@.050 cam in there, it will run out of turbo before the cam starts making power.
Mike
05-30-2009, 11:07 AM
#70
This is basically what you're dealing with, thought not quite as extreme...
http://www.theturboforums.com/smf/in...topic=124912.0
It has 3/1 backpressure and he shifts it at 5000 rpm.
If you put a 242@.050 cam in there, it will run out of turbo before the cam starts making power.
Mike
http://www.theturboforums.com/smf/in...topic=124912.0
It has 3/1 backpressure and he shifts it at 5000 rpm.
If you put a 242@.050 cam in there, it will run out of turbo before the cam starts making power.
Mike
05-30-2009, 10:49 PM
#71
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I saw you said you raised timing to 33 degrees with no knock. I am curious if the knock sensors are actually working.
Yesterday I uploaded the wrong tune with a few too many degrees of timing and the car was pinging on the top end and felt slow as poo, but I didnt record and knock at all. Reduced timing and it's doing better.
That probably has nothing to do with your power issue, but you might want to check the knock sensors.
Yesterday I uploaded the wrong tune with a few too many degrees of timing and the car was pinging on the top end and felt slow as poo, but I didnt record and knock at all. Reduced timing and it's doing better.
That probably has nothing to do with your power issue, but you might want to check the knock sensors.
05-31-2009, 12:15 AM
#72
No, at 32 I start to see knock. Also the car runs were done with racing fuel to prevent and damage from detination. The car seams to like 29 degrees of timing. The L92 heads like a little more timing then the cathedral port heads too.
05-31-2009, 05:44 PM
#74
All new developement here. I should probably repost this now.
I bought a Garrett GT88 with the T6 flange and a 1.08 a/r turbine section. I think this turbo will better fit my needs. I still plan on finishing the rear mount with this turbo. I also got the 50mm waist gate with it too.
So now will this turbo work right for me?
What cam should I go with for this set up? Everything the same just now with the GT-88 instead of the PT76GTS.
I bought a Garrett GT88 with the T6 flange and a 1.08 a/r turbine section. I think this turbo will better fit my needs. I still plan on finishing the rear mount with this turbo. I also got the 50mm waist gate with it too.
So now will this turbo work right for me?
What cam should I go with for this set up? Everything the same just now with the GT-88 instead of the PT76GTS.
06-04-2012, 12:13 PM
#76
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you ever figure out what was going on with the car? I am kinda running into the same issue (360hp 390tq) and am waiting to install the turbo untill I get it figured out. I have a 402 ls6 heads, stainless valve,s 224-228 cam, yella terra 1.7rockers, ls7 lifters, 7.4 pushrods, dual springs, fast 102, nw 102tb 9:3 compression.
