Turbo dilemma
My example is my own. So I went from a VS racing 80mm t6 88x96mm turbine on a 1.32 housing to a true north turbo 88mm t6 88x96mm on a 1.15 ar housing and that thing spools up 10x faster than that crappy 80mm ever could dream of. But that being said my 88 has a 9 blade turbine wheel where the 80 had a 10 blade that the blades were really close together
I've heard from several people that the bigger VS turbos are based on old tech and don't perform nearly as well as other name brand offerings.
Pulsar is another brand that makes a great turbo for the money.
I think the True North turbo is just a superior product compared to the VS racng offering.
I've heard from several people that the bigger VS turbos are based on old tech and don't perform nearly as well as other name brand offerings.
Pulsar is another brand that makes a great turbo for the money.
I've heard from several people that the bigger VS turbos are based on old tech and don't perform nearly as well as other name brand offerings.
Pulsar is another brand that makes a great turbo for the money.
All of the inexpensive turbos are based on older technology and are typically inferior to newer style units, but for the price difference, I look at it as such. Many of the newest turbos cost more than a lot of entire budget kits, so rather than comparing budget turbos to best turbos, I feel the better comparison is budget turbos to NA. When you look at it that way, even old turbo tech is pretty good. When I already have more power than my driveline can handle, do I really need to spend a couple of thousand for a bit better spool and more power, or would that money be better spent upgrading stuff to take advantage of the power I already have? Of course, this logic only applies to those of us on a budget, but I am betting that is a big percentage of people here.
All of the inexpensive turbos are based on older technology and are typically inferior to newer style units, but for the price difference, I look at it as such. Many of the newest turbos cost more than a lot of entire budget kits, so rather than comparing budget turbos to best turbos, I feel the better comparison is budget turbos to NA. When you look at it that way, even old turbo tech is pretty good. When I already have more power than my driveline can handle, do I really need to spend a couple of thousand for a bit better spool and more power, or would that money be better spent upgrading stuff to take advantage of the power I already have? Of course, this logic only applies to those of us on a budget, but I am betting that is a big percentage of people here.
There's half a dozen used FIS Borg turbos in the classifieds right now, I'd buy one of those before I bought a new big turbo from VS but maybe that's just me.
You have plenty of cubes to spool that turbo, a different cam won't make that big of a difference in your application.
I'd redirect that money on a quality converter and then get the tune squared away.
Those two things will make a huge difference, I'm betting you won't need to change anything else.
I'd get on the phone with someone from Circle D, PTC or FTI and see what they recommend.
Thread Starter
Launching!
Joined: Nov 2014
Posts: 234
Likes: 16
From: South dakota
Did you ever determine what the converter is?
You have plenty of cubes to spool that turbo, a different cam won't make that big of a difference in your application.
I'd redirect that money on a quality converter and then get the tune squared away.
Those two things will make a huge difference, I'm betting you won't need to change anything else.
I'd get on the phone with someone from Circle D, PTC or FTI and see what they recommend.
You have plenty of cubes to spool that turbo, a different cam won't make that big of a difference in your application.
I'd redirect that money on a quality converter and then get the tune squared away.
Those two things will make a huge difference, I'm betting you won't need to change anything else.
I'd get on the phone with someone from Circle D, PTC or FTI and see what they recommend.
@5200 on 91 pump gas 576. 12psi
i had a yank 2800.. did get it tune done, still little underwhelming at lower speed. I agree with you about the addition of a better converter making a huge difference. The reason i feel a drop in cam size, it will put the power band little lower, for the non boost drivability.
@5200 on 91 pump gas 576. 12psi
@5200 on 91 pump gas 576. 12psi
A high-quality converter that's a little looser down low would let the turbo get into its efficiency range faster and couple better up top too.
I'm very skeptical about any converter manufacturer who claims their one size fits all converter is good to 1,200whp.
When I was in talks with Circle D and Protorque, they both recommended mechanical diodes and other options for the 1,000+whp level that would negatively impact the street ability of the converter so when Yank just slaps 1,200whp on theirs, I'm very suspect.
My current Circle D converter is good to 800-900hp and is well suited for street use, to go higher in power I'd need some of the options mentioned above which also drastically increase the cost of the converter.
What I'll end up with is more slip up top probably in the 10% range but we'll see.
An 80/88 is still a good-sized turbo btw, for faster response you'd likely need something a bit smaller, but I'd do the converter first.
If 5,200 rpm is likely all the rpm you'll see then I'd definitely move to a smaller turbo, the big turbines really only shine in the higher rpm ranges.
Is it a T4 or T6 flange on the turbo?
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Brett Foote Thread Starter
Launching!
Joined: Nov 2014
Posts: 234
Likes: 16
From: South dakota
That's not bad my friend, do you have a dyno graph you can post with boost numbers?
A high-quality converter that's a little looser down low would let the turbo get into its efficiency range faster and couple better up top too.
I'm very skeptical about any converter manufacturer who claims their one size fits all converter is good to 1,200whp.
When I was in talks with Circle D and Protorque, they both recommended mechanical diodes and other options for the 1,000+whp level that would negatively impact the street ability of the converter so when Yank just slaps 1,200whp on theirs, I'm very suspect.
My current Circle D converter is good to 800-900hp and is well suited for street use, to go higher in power I'd need some of the options mentioned above which also drastically increase the cost of the converter.
What I'll end up with is more slip up top probably in the 10% range but we'll see.
An 80/88 is still a good-sized turbo btw, for faster response you'd likely need something a bit smaller, but I'd do the converter first.
If 5,200 rpm is likely all the rpm you'll see then I'd definitely move to a smaller turbo, the big turbines really only shine in the higher rpm ranges.
Is it a T4 or T6 flange on the turbo?
A high-quality converter that's a little looser down low would let the turbo get into its efficiency range faster and couple better up top too.
I'm very skeptical about any converter manufacturer who claims their one size fits all converter is good to 1,200whp.
When I was in talks with Circle D and Protorque, they both recommended mechanical diodes and other options for the 1,000+whp level that would negatively impact the street ability of the converter so when Yank just slaps 1,200whp on theirs, I'm very suspect.
My current Circle D converter is good to 800-900hp and is well suited for street use, to go higher in power I'd need some of the options mentioned above which also drastically increase the cost of the converter.
What I'll end up with is more slip up top probably in the 10% range but we'll see.
An 80/88 is still a good-sized turbo btw, for faster response you'd likely need something a bit smaller, but I'd do the converter first.
If 5,200 rpm is likely all the rpm you'll see then I'd definitely move to a smaller turbo, the big turbines really only shine in the higher rpm ranges.
Is it a T4 or T6 flange on the turbo?
i agree, seems like a lot goes in to building good converters, i also question alot of companies and there claim. However i feel Circle D has it figured out. Jusy my opinion.
i changed from the T6 housing to vband housing, Vsracing offers one. The T6 took up a good amount of real-estate to mount.
what's your thoughts on a 73mm with 1.01 a/r exhaust housing?
I'm begain to question the efficiency of this Vs turbo
Not to bad at all for a peak number. i have a graph, however it shows mph , not rpm. And no boost numbers, disappointing graph to say the least imo. He only brought it to 5200, 1) the power leveled off 2) i currently have 2bar os and it was near max out. I would like to make power to at least 6200-6800. The graph showed a narrow margin of where the power came in.
i agree, seems like a lot goes in to building good converters, i also question alot of companies and there claim. However i feel Circle D has it figured out. Jusy my opinion.
i changed from the T6 housing to vband housing, Vsracing offers one. The T6 took up a good amount of real-estate to mount.
what's your thoughts on a 73mm with 1.01 a/r exhaust housing?
I'm begain to question the efficiency of this Vs turbo
i agree, seems like a lot goes in to building good converters, i also question alot of companies and there claim. However i feel Circle D has it figured out. Jusy my opinion.
i changed from the T6 housing to vband housing, Vsracing offers one. The T6 took up a good amount of real-estate to mount.
what's your thoughts on a 73mm with 1.01 a/r exhaust housing?
I'm begain to question the efficiency of this Vs turbo
To make power out at 6,800 rpm with 400 cubes will require a turbo with a big turbine which will not be as responsive down low.
For a turbo, I'd look at a smaller unit and bring that rpm limit down to 5,500 or 6,000 especially since it's a truck and not a car.
I'd want lots of low-end torque to get it moving and not so much top end, something with a 76mm compressor and a smaller 85mm turbine.
Still an 80mm compressor but has the smaller turbine.
VSRacing 80mm billet wheel turbo T4 - LS1TECH - Camaro and Firebird Forum Discussion
You won't get much more than 12 lbs. out of pump gas unless you plan on changing fuels or adding meth injection so you should pick the turbo that will be most efficient in that range.
Poor fella. So much wrong here it makes me sad.
Is the AFR in the 11’s at least now when you are in boost? If your tuner is stopping at 5200 with no explanation as to why... get a new tuner. That cam (with the correct springs) should pull well past that with your setup. Shouldn’t fall offline until 6700+ . If it is, something is wrong.
The converter is absolutely key and likely the most important part on a turbo setup. You should never be worried about power below 3500 as you should be flashing to 3500+ immediately when you stomp the gas. If not, you have the wrong converter. (wrong converter for your turbo anyway). If you want lockup, just ask for Circle D’s loosest non diode lockup converter. I’ve yet to see a circle D converter stall to the RPM they quoted it to. They have always been tighter than quoted.
last I spoke with them the “pro series” 258mm converter was available up toa 3700 rpm stall. (may be new options now) When purchased the “3700 RPM stall” only flashed to 3400 behind a moderate cam 6.0 w factory heads.
Is the AFR in the 11’s at least now when you are in boost? If your tuner is stopping at 5200 with no explanation as to why... get a new tuner. That cam (with the correct springs) should pull well past that with your setup. Shouldn’t fall offline until 6700+ . If it is, something is wrong.
The converter is absolutely key and likely the most important part on a turbo setup. You should never be worried about power below 3500 as you should be flashing to 3500+ immediately when you stomp the gas. If not, you have the wrong converter. (wrong converter for your turbo anyway). If you want lockup, just ask for Circle D’s loosest non diode lockup converter. I’ve yet to see a circle D converter stall to the RPM they quoted it to. They have always been tighter than quoted.
last I spoke with them the “pro series” 258mm converter was available up toa 3700 rpm stall. (may be new options now) When purchased the “3700 RPM stall” only flashed to 3400 behind a moderate cam 6.0 w factory heads.
Poor fella. So much wrong here it makes me sad.
Is the AFR in the 11’s at least now when you are in boost? If your tuner is stopping at 5200 with no explanation as to why... get a new tuner. That cam (with the correct springs) should pull well past that with your setup. Shouldn’t fall offline until 6700+ . If it is, something is wrong.
The converter is absolutely key and likely the most important part on a turbo setup. You should never be worried about power below 3500 as you should be flashing to 3500+ immediately when you stomp the gas. If not, you have the wrong converter. (wrong converter for your turbo anyway). If you want lockup, just ask for Circle D’s loosest non diode lockup converter. I’ve yet to see a circle D converter stall to the RPM they quoted it to. They have always been tighter than quoted.
last I spoke with them the “pro series” 258mm converter was available up toa 3700 rpm stall. (may be new options now) When purchased the “3700 RPM stall” only flashed to 3400 behind a moderate cam 6.0 w factory heads.
Is the AFR in the 11’s at least now when you are in boost? If your tuner is stopping at 5200 with no explanation as to why... get a new tuner. That cam (with the correct springs) should pull well past that with your setup. Shouldn’t fall offline until 6700+ . If it is, something is wrong.
The converter is absolutely key and likely the most important part on a turbo setup. You should never be worried about power below 3500 as you should be flashing to 3500+ immediately when you stomp the gas. If not, you have the wrong converter. (wrong converter for your turbo anyway). If you want lockup, just ask for Circle D’s loosest non diode lockup converter. I’ve yet to see a circle D converter stall to the RPM they quoted it to. They have always been tighter than quoted.
last I spoke with them the “pro series” 258mm converter was available up toa 3700 rpm stall. (may be new options now) When purchased the “3700 RPM stall” only flashed to 3400 behind a moderate cam 6.0 w factory heads.
If he's making 12lbs. at 5,200, it should carry out to 6,700rpm without issue regardless of the map sensor.
Maybe the OP can post the tune file?
I wouldn't do anything until I addressed the converter if it was me and get a second opinion on the tune.
I think mine is the 258mm as well, stall has to be up there somewhere, I've run it up 4,000rpm on the TB, I think if you want more stall, it's the next size down diameter iirc.
It drives really nice, doesn't generate a lot of heat and seems to lock up quite well on the street.
As I said, the fact Yank says theirs is good to 1,200whp and is so cheap is a red flag to me when Circle D, ATI and ProTorque have come back with something totally different and way more expensive at that power level.
Thread Starter
Launching!
Joined: Nov 2014
Posts: 234
Likes: 16
From: South dakota
Thanks guy's for offering advice, tuner did explain the reason for 5200 limit, i mention this above....He only brought it to 5200, 1) the power leveled off , 2) i currently have 2bar os and it was near max out. the changes i will make will be to E85, due to the limitations i will also swap to 3bar os. i have a 3bar MAP, however the table for the 2bar is a bit more "detailed ". Then the 3bar (0411 ecm) also i am switching out the SS2 Cam, like theballss mentioned maybe around 76mm. Precision makes a Ls series 76/75, with the option to choose an a/r size housing.
what determines the a/r size for the exhaust housing, or what are things to consider?
what determines the a/r size for the exhaust housing, or what are things to consider?
Thanks guy's for offering advice, tuner did explain the reason for 5200 limit, i mention this above....He only brought it to 5200, 1) the power leveled off , 2) i currently have 2bar os and it was near max out. the changes i will make will be to E85, due to the limitations i will also swap to 3bar os. i have a 3bar MAP, however the table for the 2bar is a bit more "detailed ". Then the 3bar (0411 ecm) also i am switching out the SS2 Cam, like theballss mentioned maybe around 76mm. Precision makes a Ls series 76/75, with the option to choose an a/r size housing.
what determines the a/r size for the exhaust housing, or what are things to consider?
what determines the a/r size for the exhaust housing, or what are things to consider?
If you want to shift at 6,800 rpm, I wouldn't do a Precision 7675, you've already got the room for a large frame turbo so stick with it.
If the tuner says the 2 bar sensor is the problem and you intend making more boost anyway, upgrade to the 3 bar, put it on E85 and see what it does.
Don't throw anymore parts at it like a cam or turbo until you get it running right or you may just end up flushing money down the drain.
Post the tune here if you can, lots of guys here who can tell you if it's where it needs to be.
If the tune is soft on timing down low, that'll affect turbo spool, lots of little tricks experienced tuners can employ that your guy may not be aware of.
I’m confused by what cam you are actually running? At one point above you said you had a SS2, now you are talking about switching to a SS2? I was thinking you had the Tick Performance SNS LS2 stage 2 231/235 in your signature. Which is a better cam than the SS2 for a 400" motor.
The sloppy is a 228° / 230° on a 112. That will behave similarly with less power all round with less peak rpm. Silly to change between the two.
You have a relatively large motor. You don’t want to go from your current S480 87mm turbine wheel to 75mm turbine wheel. It will choke at moderate power/RPM on such a big motor. Walk away from whomever is putting these suggestions in your head.
Don’t replace BS parts just to replace them. Replace the converter. That’s the issue with your current combo.
Nothing is wrong with the cam or the turbo. If you read about the SNS LS2 stage 2 231/235 cam (we assume is in your car now) it states 3600rpm stall recommended. And 6600 rpm peak. You can generally squeak out an additional 500-1000 rpm with a turbo combo from the rated rpm. You can’t run a factory converter with that cam and expect it to perform well.
Thread Starter
Launching!
Joined: Nov 2014
Posts: 234
Likes: 16
From: South dakota
That statement also makes no sense to me. RPM has nothing to do with MAP. Max out the map at 1 bar (14.7 psi) and you can run it to any RPM you want. Was the engine running out of fuel at 5200 maybe? It shouldn’t be falling flat at 5200 with that cam. That was my point. If it is, something is wrong.
I’m confused by what cam you are actually running? At one point above you said you had a SS2, now you are talking about switching to a SS2? I was thinking you had the Tick Performance SNS LS2 stage 2 231/235 in your signature. Which is a better cam than the SS2 for a 400" motor.
The sloppy is a 228° / 230° on a 112. That will behave similarly with less power all round with less peak rpm. Silly to change between the two.
You have a relatively large motor. You don’t want to go from your current S480 87mm turbine wheel to 75mm turbine wheel. It will choke at moderate power/RPM on such a big motor. Walk away from whomever is putting these suggestions in your head.
Don’t replace BS parts just to replace them. Replace the converter. That’s the issue with your current combo.
Nothing is wrong with the cam or the turbo. If you read about the SNS LS2 stage 2 231/235 cam (we assume is in your car now) it states 3600rpm stall recommended. And 6600 rpm peak. You can generally squeak out an additional 500-1000 rpm with a turbo combo from the rated rpm. You can’t run a factory converter with that cam and expect it to perform well.
I’m confused by what cam you are actually running? At one point above you said you had a SS2, now you are talking about switching to a SS2? I was thinking you had the Tick Performance SNS LS2 stage 2 231/235 in your signature. Which is a better cam than the SS2 for a 400" motor.
The sloppy is a 228° / 230° on a 112. That will behave similarly with less power all round with less peak rpm. Silly to change between the two.
You have a relatively large motor. You don’t want to go from your current S480 87mm turbine wheel to 75mm turbine wheel. It will choke at moderate power/RPM on such a big motor. Walk away from whomever is putting these suggestions in your head.
Don’t replace BS parts just to replace them. Replace the converter. That’s the issue with your current combo.
Nothing is wrong with the cam or the turbo. If you read about the SNS LS2 stage 2 231/235 cam (we assume is in your car now) it states 3600rpm stall recommended. And 6600 rpm peak. You can generally squeak out an additional 500-1000 rpm with a turbo combo from the rated rpm. You can’t run a factory converter with that cam and expect it to perform well.
I agree, and felt the same way about only making power to 5200, regardless of the MAP. and i though the 2bar table should've covered at least to 15psi.
The reason I would like to swap cam, is to gain better torque lower in the rpm, out of boost. It is an idea i had.
Overall Something is definitely not right with the truck/tune whichever it is.
I will post the tune later tonight. A problem with the truck came about, not that the tune caused it, i would like to get opinions on the tune first.
You can add a bleed inline with the map sensor and tune a 2 bar to easily run 20lbs or more if you want. Just need to scale the table. It is completely independent of RPM.
The SS2 cam is a bit smaller and may peter off earlier than I thought on a 400” motor. Esp if you have decent heads on it. You can look at all the Holdner 6.0 tests and see it routinely pulls to 6600 or so on an NA 6.0. I’d go bigger for your motor, but I don’t think thats the 5200rpm issue. No matter what I’d change the converter first. Its a night/day diff.
The SS2 cam is a bit smaller and may peter off earlier than I thought on a 400” motor. Esp if you have decent heads on it. You can look at all the Holdner 6.0 tests and see it routinely pulls to 6600 or so on an NA 6.0. I’d go bigger for your motor, but I don’t think thats the 5200rpm issue. No matter what I’d change the converter first. Its a night/day diff.
Thread Starter
Launching!
Joined: Nov 2014
Posts: 234
Likes: 16
From: South dakota
You can add a bleed inline with the map sensor and tune a 2 bar to easily run 20lbs or more if you want. Just need to scale the table. It is completely independent of RPM.
The SS2 cam is a bit smaller and may peter off earlier than I thought on a 400” motor. Esp if you have decent heads on it. You can look at all the Holdner 6.0 tests and see it routinely pulls to 6600 or so on an NA 6.0. I’d go bigger for your motor, but I don’t think thats the 5200rpm issue. No matter what I’d change the converter first. Its a night/day diff.
The SS2 cam is a bit smaller and may peter off earlier than I thought on a 400” motor. Esp if you have decent heads on it. You can look at all the Holdner 6.0 tests and see it routinely pulls to 6600 or so on an NA 6.0. I’d go bigger for your motor, but I don’t think thats the 5200rpm issue. No matter what I’d change the converter first. Its a night/day diff.
I'm not set on having to have the power up to 6800, not if that means sacrificing low-mid power. i feel a larger cam would result in this, I agree about the 5200 issue not being related to the cam selection, something else isn't jiving.
i will be adding a circle D, and just as you all said (which is why i posted on here), they to suggest a 3800+, 245mm. this is with a 212/22x cam.
I'm not set on having to have the power up to 6800, not if that means sacrificing low-mid power. i feel a larger cam would result in this, I agree about the 5200 issue not being related to the cam selection, something else isn't jiving.
I'm not set on having to have the power up to 6800, not if that means sacrificing low-mid power. i feel a larger cam would result in this, I agree about the 5200 issue not being related to the cam selection, something else isn't jiving.
Wait and see what it does, that may be the only change needed parts wise.
Currently I run an S484 with the 96mm turbine and 1.36AR on a little 5.7 and it'll start building boost around 3,600rpm which is where the converter is working so imagine what yours will do now.
In general ,you want RPM. The more the better in most cases. You don’t want to start applying “Real power” until you are past PK TQ rpm. Applying decent amounts of boost before PK TQ is very hard on the motor. Bends rods, munches pistons, pops head gaskets etc.... So if you make PK TQ at 4500 and are done by 5200. That gives you 700 whole rpm to run decent boost/power. You should be revving that motor to 7k or so.