Changing turbo, which one now?? - LS1TECH - Camaro and Firebird Forum Discussion

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Changing turbo, which one now??

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Old 09-13-2018, 08:29 PM
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Default Changing turbo, which one now??

I DD a 99 Camaro with a SBE gen 4 5.3, t56 and a v3 Huron speed single turbo kit with a 7875 .96.... My goals haven't changed for the car since the build, I want a fun DD making around 550-600. However, my setup is pretty laggy, I have low compression and a baby cam.... I have to pull the turbo off to replace the gasket on the flange so I've been thinking about switching out the turbo.....
Goals are: 550-600whp, less lag and I should probably mention I don't rev very high(I get hell from my friends all the time lol) I only rev to 6-6200 usually.

Turbos I'm looking at are
7868 .96
Or
6673 .91
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Old 09-13-2018, 10:06 PM
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Why not swap heads or cam? That turbo isnt really laggy by any stretch.
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Old 09-13-2018, 10:17 PM
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You have something very wrong with your setup if it's laggy. My 7875 lights off immediately and my buddy also has a 7875 and it's pretty much the same. Mine starts making boost at about 2800 and is all in by 3k. I'm actually wanting to go with a bigger turbo now to get some lag.
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Old 09-13-2018, 10:27 PM
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try the new on 3 7675 BMF
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Old 09-13-2018, 10:59 PM
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Originally Posted by MY_2K_Z View Post
You have something very wrong with your setup if it's laggy. My 7875 lights off immediately and my buddy also has a 7875 and it's pretty much the same. Mine starts making boost at about 2800 and is all in by 3k. I'm actually wanting to go with a bigger turbo now to get some lag.
I am tuned on the conservative side so that may play a role in the lag I'm experiencing I suppose.....my flange gasket leak probably isn't helping either
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Old 09-14-2018, 12:33 AM
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I have the same turbo, and I would be astonished if your tune up was any more conservative than mine. And it will light off if I breathe on the gas pedal. Those small turbos you mentioned will light off stupid fast, but imo the car won't be much fun.
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Old 09-14-2018, 09:45 AM
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Originally Posted by MY_2K_Z View Post
You have something very wrong with your setup if it's laggy. My 7875 lights off immediately and my buddy also has a 7875 and it's pretty much the same. Mine starts making boost at about 2800 and is all in by 3k. I'm actually wanting to go with a bigger turbo now to get some lag.
Whats your cubes and compression ratio?
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Old 09-14-2018, 09:46 AM
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Originally Posted by Game ova View Post
I have the same turbo, and I would be astonished if your tune up was any more conservative than mine. And it will light off if I breathe on the gas pedal. Those small turbos you mentioned will light off stupid fast, but imo the car won't be much fun.
I would imagine your 6 liter auto would spool faster than a 9:1 5.3 6 speed.
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Old 09-14-2018, 09:55 AM
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Originally Posted by ddnspider View Post
I would imagine your 6 liter auto would spool faster than a 9:1 5.3 6 speed.
Remember now, I auto swapped a couple years ago. I remember the 6 speed life well . But I do agree, a 6.0 may spool it a touch quicker....a touch.
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Old 09-14-2018, 09:59 AM
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I'd stick with the 7875 and work on optimizing your setup, if the heads on the 5.3 are stock and what came on the engine the compression shouldn't be that low.
Install a turbo specific cam, fix the leak, optimize the tune and on 10-12 lbs. you should easily meet your hp goal and be fun to drive on the street.
I ran the 7868 for a while but it was a pita with a manual, the power comes on like a light switch and chokes out around 5,500 rpm.
The 7875 will make more power with longer legs.
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Old 09-14-2018, 10:21 AM
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Originally Posted by The ****** View Post
I'd stick with the 7875 and work on optimizing your setup, if the heads on the 5.3 are stock and what came on the engine the compression shouldn't be that low.
Install a turbo specific cam, fix the leak, optimize the tune and on 10-12 lbs. you should easily meet your hp goal and be fun to drive on the street.
I ran the 7868 for a while but it was a pita with a manual, the power comes on like a light switch and chokes out around 5,500 rpm.
The 7875 will make more power with longer legs.
The 5.3 I have usually comes with 243 heads making it 9.9 compression, I switched to 241 heads for the bigger combustion chamber so I'm assuming it's in the low 9's, not sure exactly..... Either way, low compression, 325 cubes on a conservative tune, baby cam is probably hurting the spool....I'm not trying to break records, just want to make decent power in my DD
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Old 09-14-2018, 10:25 AM
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Do you tune the car yourself? How conservative is your tune. Timing should be pretty aggressive up until a couple pounds then tapper it off quickly. I'd put the 243s back on, adjust the tune and see how it feels. And the cam shouldn't be to much of a factor imo, I had a stock ls3 cam and the spook was the same.
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Old 09-14-2018, 10:25 AM
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Please don't take this as bashing, and I understand that you didn't ask for an opinion on this. But I wouldn't recommend having a car like this as your sole means of transportation. At the very least, I'd get a $1,000 beater if you can't afford something new. That way you don't HAVE to fix the car right then when it breaks, I say when.... because it will.
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Old 09-14-2018, 10:56 AM
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Originally Posted by Game ova View Post
Please don't take this as bashing, and I understand that you didn't ask for an opinion on this. But I wouldn't recommend having a car like this as your sole means of transportation. At the very least, I'd get a $1,000 beater if you can't afford something new. That way you don't HAVE to fix the car right then when it breaks, I say when.... because it will.
Lol no offense taken.... Its not the most ideal situation, just kind of how things have unfolded lol... But yes I'm looking for a real DD...
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Old 09-14-2018, 11:49 AM
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Originally Posted by ls1charged View Post
The 5.3 I have usually comes with 243 heads making it 9.9 compression, I switched to 241 heads for the bigger combustion chamber so I'm assuming it's in the low 9's, not sure exactly..... Either way, low compression, 325 cubes on a conservative tune, baby cam is probably hurting the spool....I'm not trying to break records, just want to make decent power in my DD
I'm not familiar with the 241 heads but if they are like the 317 and you have dished pistons in the 5.3 your comp will be quite low, like mid 8's low.
That will of course affect spool but there are quite a few guys on here who say that can be mitigated in the tune, if the compression is low then a conservative tune becomes unnecessary, get more aggressive with it and you may find you don't need to do anything else.
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Old 09-14-2018, 11:51 AM
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What are you calling laggy?

We have the same set up (with the exception of a turbo cam and a 7575 on my end) and mine comes alive at 2800 and is all in by 3500.

Try replacing the gasket before doing anything else, bet it helps quite a bit.

Forgot to mention, my turbo has a 1.15 ar...

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Old 09-14-2018, 11:54 AM
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Originally Posted by The ****** View Post
I'm not familiar with the 241 heads but if they are like the 317 and you have dished pistons in the 5.3 your comp will be quite low, like mid 8's low.
That will of course affect spool but there are quite a few guys on here who say that can be mitigated in the tune, if the compression is low then a conservative tune becomes unnecessary, get more aggressive with it and you may find you don't need to do anything else.
Gen 4's have flat top pistons with small valve reliefs. A set of 241's on top puts it at mid 9's compression.
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Old 09-14-2018, 11:55 AM
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A billet S480/87 1.10 T4 on my 5.3 with a baby cam spools like a light switch. The torque is brutal, power is always there.

Something is wrong.
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Old 09-14-2018, 12:01 PM
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I would make sure you dont have any leaks on your hotwire or coldside.

at what rpm are you seeing boost? Remember, more boost at low rpms is also harder on roads and bearings. I would think that turbo should be lit off pretty well by 3k rpm, at least in 3rd gear or above anyway.
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Old 09-14-2018, 12:19 PM
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Originally Posted by stoverz28 View Post
Gen 4's have flat top pistons with small valve reliefs. A set of 241's on top puts it at mid 9's compression.
My Gen IV LM7 had dished pistons, from what I've researched only the L33 and 4.8's had flat tops.
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