My observations and opinions of current street/strip turbo LS trends.
08-22-2012, 07:55 AM
#201
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Since we are discussing combinations here, will twin GT35 turbos (T3 flange) .82 AR support 700 rwhp with a 5.3 and a TU1 cam, E85 ? I would like this to be all in at 15 psi.
My latest engine is an LH6 with 10.3 compression and ported 862 heads.
Now would be the time to change parts if needed.
My latest engine is an LH6 with 10.3 compression and ported 862 heads.
Now would be the time to change parts if needed.
08-22-2012, 08:18 AM
#203
Thanks the post. I appreciate the info.
Can you supply a good 1000whp combo or is that something that would take money from your business.
I have completed a L92 swap in my 1968 BelAir with the end goal of having a 1000whp street BEAST/Daily Driveable family car.
The motor is so far untouched.
The goal was to build a custom twin setup using the '10 Camaro manifolds that i'm currently using with the stock motor and aim for about 500-600whp.
Later when everything was working well together and I had the basic tune sorted, I would build bottom end(rods, piston, compression change, extra cubes perhaps), cam, springs, etc needed to take more boost and hit that.
Can you help with the final combo that will get me there?
Also, I rebuilt my tank with a aeromotive pump and the ability to add a second for 1300-1400 capacity. I also used a 1/2 and -8 feed line. So that's already done with the 1000whp goal in mind.
Obviously a 1000hp capable 6-speed and rear end will also be in the mix. And brakes!
Can you supply a good 1000whp combo or is that something that would take money from your business.
I have completed a L92 swap in my 1968 BelAir with the end goal of having a 1000whp street BEAST/Daily Driveable family car.
The motor is so far untouched.
The goal was to build a custom twin setup using the '10 Camaro manifolds that i'm currently using with the stock motor and aim for about 500-600whp.
Later when everything was working well together and I had the basic tune sorted, I would build bottom end(rods, piston, compression change, extra cubes perhaps), cam, springs, etc needed to take more boost and hit that.
Can you help with the final combo that will get me there?
Also, I rebuilt my tank with a aeromotive pump and the ability to add a second for 1300-1400 capacity. I also used a 1/2 and -8 feed line. So that's already done with the 1000whp goal in mind.
Obviously a 1000hp capable 6-speed and rear end will also be in the mix. And brakes!
08-22-2012, 09:27 AM
#204
Maybe I missed it in here somewhere... But the original post was observing people not selecting the proper turbo.... more so turbine side. Twice now in 2 days ive discussed this with people, and it still doesnt look like it was covered in here. Someone should write up something explaining the whole theory (simplified) to people in regards to turbine side, air flow, and the fact that the turbine side has to sustain the present air flow of the cubic inches AND the additional air the compressor side will add. I know there are formulas and stuff... But when people dont understand the general concept they sure as hell are not going to have a clue what the formulas are......they take one look at that and say....."I'll just get that turbo because I seen a thread that someone else used it".
08-22-2012, 10:00 AM
#206
That's why I presented all the metrics of my engine, car, goals and driving style to Jim and he came back with two configurations. Jim knows the formulas and how to use the information derived from them.
- A single PT76GTS .96 A/R
- Two PT 6067E
Maybe I missed it in here somewhere... But the original post was observing people not selecting the proper turbo.... more so turbine side. Twice now in 2 days ive discussed this with people, and it still doesnt look like it was covered in here. Someone should write up something explaining the whole theory (simplified) to people in regards to turbine side, air flow, and the fact that the turbine side has to sustain the present air flow of the cubic inches AND the additional air the compressor side will add. I know there are formulas and stuff... But when people dont understand the general concept they sure as hell are not going to have a clue what the formulas are......they take one look at that and say....."I'll just get that turbo because I seen a thread that someone else used it".
08-22-2012, 10:49 AM
#207
Again, a master spread sheet with PROVEN engine/turbo(s) combinations would lay all of the "What turbo(s) should my 4.8/5.3/5.7/6.0/6.2/7.0 L engine have" questions to rest.
This thread is going to turn into a free-for-all turbo therapy session and Jim is expected to be head shrink!
And the same questions will be asked in a week....and the week after that...
For those with data to back up their combo, PM me with the data and I will start a spread sheet so that we can show all that having a central database will help everyone build better cars without the headache of not knowing if the engine is sized for the turbo(s) and visa verse.
The database could also help indecisive people determine what setup they want so when they go to a supporting vendor, they can have a clear decision on "I want twin 6262's on my 370".
This thread is going to turn into a free-for-all turbo therapy session and Jim is expected to be head shrink!
And the same questions will be asked in a week....and the week after that...
For those with data to back up their combo, PM me with the data and I will start a spread sheet so that we can show all that having a central database will help everyone build better cars without the headache of not knowing if the engine is sized for the turbo(s) and visa verse.
The database could also help indecisive people determine what setup they want so when they go to a supporting vendor, they can have a clear decision on "I want twin 6262's on my 370".
Last edited by Chicago TDP; 08-22-2012 at 10:54 AM.
08-22-2012, 11:26 AM
#208
^ what is a proven combo for one can work totally different for another unless they match the build 100%... and no one does that. This would be like the .bin repository and people posting their tune files.... You can have the same combo but there are too many variables that effect the entire thing that no two would function the same.
A spread sheet with the basics would help.. say each cubic inch engine and what the max air flow per engine is (general). And then a chart of general off the shelf turbos and what they flow and how the 2 match up, and what the smallest turbine you want to run on a XXX cubic inch engine and the largest to make XXX hp. ...and so on. Of course you'd have to write out a basic lesson of how it all works too.
A spread sheet with the basics would help.. say each cubic inch engine and what the max air flow per engine is (general). And then a chart of general off the shelf turbos and what they flow and how the 2 match up, and what the smallest turbine you want to run on a XXX cubic inch engine and the largest to make XXX hp. ...and so on. Of course you'd have to write out a basic lesson of how it all works too.
08-22-2012, 11:36 AM
#209
Pwrtrip,
You and I are on the same page.
I am in it for the general details.
If one were to look into more specific details or try and make a carbon copy of a build, so be it....builder beware!
Hell, it would be interesting to compare a notch back and camaro with the same power combo (ET wise).
The more details in to go along with the combo, the better.
I know that you have made a couple interesting combos with good results and have learned a lot on the way.
But all said and done, having a one-stop-shop spread sheet to answer all of these questions would stop the broken record posts about "What turbo with my engine???"
Taking serious emails....
Feartheengineer434@sbcglobal.net
You and I are on the same page.
I am in it for the general details.
If one were to look into more specific details or try and make a carbon copy of a build, so be it....builder beware!
Hell, it would be interesting to compare a notch back and camaro with the same power combo (ET wise).
The more details in to go along with the combo, the better.
I know that you have made a couple interesting combos with good results and have learned a lot on the way.
But all said and done, having a one-stop-shop spread sheet to answer all of these questions would stop the broken record posts about "What turbo with my engine???"
Taking serious emails....
Feartheengineer434@sbcglobal.net
08-22-2012, 04:05 PM
#211
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Dr.turbo said the matchbot is a toy to play with but needs alot of refining. So I'm guessing its of a bit. That's where I went after the start of this thread in hopes of making sure the turbo I bought will be right for my combo.
08-22-2012, 04:14 PM
#212
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08-22-2012, 07:23 PM
#213
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The following thoughts and rambling is directed towards what I see as the majority of the street/strip turbo LS crowd. As a disclaimer, the following is my -opinion- but it is backed by experience. Oh yeah, and I don't sugar coat things.
First off, the same with anything, a turbo LS needs to be looked at as an entire, matched combination. Set your goals first and then decide on components that will allow you to reach those goals.
That being said, big compressor wheels and tiny turbines seem to be all the rage these days. Guess it makes for an affordable turbo. It also makes for sub-par performance.
If you've decided that you absolutely must use a 76mm compressor and a 12mm turbine
, really don't even bother with a "what cam should I use" thread because if you have money for a cam that will do absolutely nothing for you, it should be spent towards a turbo that is actually capable of efficiently making power.
Why does your car nose over at 5k? Chances are your turbo belongs in the dumpster or you have way too big of an engine for your current turbo. Want to make 950rwhp and 7000rpm with a PT7675? Run a 5.3. Want to spend more money on a 408 and max out the same turbo at 775rwhp and 5200rpm? Probably not, but people do it.
Not sure why but it seems many people shy away from twin setups. Twins absolutely cannot be beat in terms of a fun street car. Even an undersized pair of twins that make nearly instant boost will still outshine most similarly capable singles up top. I don't like lag so I always run twins. And I'm not talking logged boost VS wot, I'm talking about having driven countless amount of turbo cars and knowing the difference in feel when you roll on the gas of a single or a small set of similarly capable twins. Transient response is what you feel in normal every day driving and you get it in spades with a good twin setup.
Rear mount? Sure they can be fast at the strip as you have time to get the things online while you're bumping it in. As for a fun driving combination on the street? None that I've driven accomplish that. Wouldn't use it if it was given to me. (refer to, I don't like lag so I run twins/etc/etc)
Back to the cam thing. I'll use the cams we have available as examples because well, why not. I designed them and tuned them over the years so at least I can speak about them with experience.
TUO-216/216 114lsa. I would plan on bigger if I planned on over 700rwhp.
TU1-225/225 113lsa. I may consider a bigger cam if 950rwhp wasn't enough.
TU2-236/236 112.5lsa. If you have a combo capable of 1200rwhp and 7800rpm than this cam will work great.
Guess the point I'm trying to make on cams is that I think 90% of people cheap out on their turbo then over-cam the hell out of it thinking it will somehow compensate when in reality all you did was soften up the bottom end and midrange for no gains up top.
So, in closing, if you're building or planning a build on a turbo LS and your goal is to not be disappointed, THE most important thing to buy is a good turbocharger or turbochargers. Second is valvesprings. If you cheaped out on the turbo so you could buy more cubes, a different intake manifold, a different cam, a set of heads, a throttle body, an electric water pump, or even a torque converter, you've made a poor decision.
Rant over, let the flames begin
First off, the same with anything, a turbo LS needs to be looked at as an entire, matched combination. Set your goals first and then decide on components that will allow you to reach those goals.
That being said, big compressor wheels and tiny turbines seem to be all the rage these days. Guess it makes for an affordable turbo. It also makes for sub-par performance.
If you've decided that you absolutely must use a 76mm compressor and a 12mm turbine
, really don't even bother with a "what cam should I use" thread because if you have money for a cam that will do absolutely nothing for you, it should be spent towards a turbo that is actually capable of efficiently making power. Why does your car nose over at 5k? Chances are your turbo belongs in the dumpster or you have way too big of an engine for your current turbo. Want to make 950rwhp and 7000rpm with a PT7675? Run a 5.3. Want to spend more money on a 408 and max out the same turbo at 775rwhp and 5200rpm? Probably not, but people do it.
Not sure why but it seems many people shy away from twin setups. Twins absolutely cannot be beat in terms of a fun street car. Even an undersized pair of twins that make nearly instant boost will still outshine most similarly capable singles up top. I don't like lag so I always run twins. And I'm not talking logged boost VS wot, I'm talking about having driven countless amount of turbo cars and knowing the difference in feel when you roll on the gas of a single or a small set of similarly capable twins. Transient response is what you feel in normal every day driving and you get it in spades with a good twin setup.
Rear mount? Sure they can be fast at the strip as you have time to get the things online while you're bumping it in. As for a fun driving combination on the street? None that I've driven accomplish that. Wouldn't use it if it was given to me. (refer to, I don't like lag so I run twins/etc/etc)
Back to the cam thing. I'll use the cams we have available as examples because well, why not. I designed them and tuned them over the years so at least I can speak about them with experience.
TUO-216/216 114lsa. I would plan on bigger if I planned on over 700rwhp.
TU1-225/225 113lsa. I may consider a bigger cam if 950rwhp wasn't enough.
TU2-236/236 112.5lsa. If you have a combo capable of 1200rwhp and 7800rpm than this cam will work great.
Guess the point I'm trying to make on cams is that I think 90% of people cheap out on their turbo then over-cam the hell out of it thinking it will somehow compensate when in reality all you did was soften up the bottom end and midrange for no gains up top.
So, in closing, if you're building or planning a build on a turbo LS and your goal is to not be disappointed, THE most important thing to buy is a good turbocharger or turbochargers. Second is valvesprings. If you cheaped out on the turbo so you could buy more cubes, a different intake manifold, a different cam, a set of heads, a throttle body, an electric water pump, or even a torque converter, you've made a poor decision.
Rant over, let the flames begin
My custom STS single set up won't frighten anyone used to TT V8 power, but I like it as a starting point (it is my first turbo V8 and I had to run with a stock LS1 that had 100,000 miles on it - though leak down and compression was excellent).
Pre-turbo - with stock converter and tall 3.07:1 rear gears the stock auto and NA engine could not spin the wheels not matter how fast you slapped the pedal down - it just hooked and went. That was in 288rwhp tune.
I added a turbo cam (222/226 on 114/116 lobes with 0.575 lift) and that got it to 335rwhp and with a mild converter it would break traction if provoked but only from a dig.
The final tune on my 6psi STS setup (with upgraded ball bearing STS 75 T4E/T4V P-trim (67) on STS T4 P trim turbine 0.81 AR) will light up from dig or if provoked at anything under around 20mph even without full throttle. The turbo hits quick enough and at no point is it slower than when it was non turbo'd.
My only gripe is that while the cam helped the old LS1 achieve 450rwhp at 6psi on pump gas (with water/meth) the cam cost noticable mpg at cruise. No lean tune can get it back. However I don't want to drop 50rwhp to go back to the stock cam. That stock cam was amazing on gas however, and my first serious built engine may run more boost and stockish cam for that reason.
I see you use symmetrical cams - I always thought those hurt mpg compared to running a split pattern that matched the hp and ran more exhaust
08-22-2012, 08:01 PM
#214
My only gripe is that while the cam helped the old LS1 achieve 450rwhp at 6psi on pump gas (with water/meth) the cam cost noticable mpg at cruise. No lean tune can get it back. However I don't want to drop 50rwhp to go back to the stock cam. That stock cam was amazing on gas however, and my first serious built engine may run more boost and stockish cam for that reason.
I see you use symmetrical cams - I always thought those hurt mpg compared to running a split pattern that matched the hp and ran more exhaust
I see you use symmetrical cams - I always thought those hurt mpg compared to running a split pattern that matched the hp and ran more exhaust
08-22-2012, 08:19 PM
#215
It is as accurate as the information you input into it I would say. I would hazard to guess that most people do not know the BSFC of their motors off hand. I know I do not. I think it is a little idealistic in some of its calculations, but I think it is a decent tool to play around with different sized turbos. The bad part is that it only has OEM BW turbos on it and mainly just the EFR series.
08-22-2012, 10:05 PM
#216
FormerVendor
Thread Starter
In terms of turbo selection allow me to refer back to the original post " Set your goals first and then decide on components that will allow you to reach those goals"
It is good to look at other combos to see if what someone else has achieved is what you want to achieve. Did it make enough power? Where is peak torque on the dyno graph? Typically if you are looking at a dyno graph of a manual car or auto with locked converter, peak torque will occur right around where it hits peak boost.
IMO, most combos that are a good trade-off between being responsive in normal driving situations but also able to make good power up top will hit peak boost/torque in the 4300-4500rpm range. If a combo can hit peak boost at a lower rpm than that you will have much more low rpm response at the expense of high rpm power. If it makes peak boost/torque much higher than that and you are trading low/mid range response for high rpm power. (usually).
I say usually because some combos with an unusually large exhaust A/R or just an oversized turbo(s) altogether may just be leaving low and midrange on the table for no gains up top.
Some basics on compressor maps. If you want to look through them, remember that roughly 10lbs/min = 100hp. So for example lets take a look at a Garrett GT3582R
As you can see, it's capable of roughly a bit over 60lbs/min maxed out which would be equal to around 1200 crank horsepower in twin configuration. Now just decide on exhaust a/r vs cubic inch or how responsive you want it to be. More cubes can get away with a bigger a/r. Smaller cubes will want to keep the a/r tight to reduce lag.
Remember that a turbo will not make more power than what the compressor map shows it capable of but it will also not make what the map shows it's capable of if you do not have enough flow on the exhaust side.
Once you've found a turbo or turbos capable of flowing what you need on the compressor side, take a look at the turbine. The turbine should be roughly the same size or larger than the compressor. This is a good indication of a well matched turbo. Again, when you see the turbine size as much smaller than the compressor this generally will not be a very efficient unit and will cause backpressure issues on a single and possible massive boost creep with twins.
There are always exceptions and the above info is just very basic. Many times if I think I've found a turbo I want to run in twin configuration I'll look online and see how well it's done with the 4 cylinder guys. They will extensively do back to back dyno tests with the smaller turbos so by reading those tests and viewing there dyno charts you can get an idea of how good the unit is.
For more reading, this is excellent-
http://www.turbobygarrett.com/turbob...Catalog_V4.pdf
It is good to look at other combos to see if what someone else has achieved is what you want to achieve. Did it make enough power? Where is peak torque on the dyno graph? Typically if you are looking at a dyno graph of a manual car or auto with locked converter, peak torque will occur right around where it hits peak boost.
IMO, most combos that are a good trade-off between being responsive in normal driving situations but also able to make good power up top will hit peak boost/torque in the 4300-4500rpm range. If a combo can hit peak boost at a lower rpm than that you will have much more low rpm response at the expense of high rpm power. If it makes peak boost/torque much higher than that and you are trading low/mid range response for high rpm power. (usually).
I say usually because some combos with an unusually large exhaust A/R or just an oversized turbo(s) altogether may just be leaving low and midrange on the table for no gains up top.
Some basics on compressor maps. If you want to look through them, remember that roughly 10lbs/min = 100hp. So for example lets take a look at a Garrett GT3582R
As you can see, it's capable of roughly a bit over 60lbs/min maxed out which would be equal to around 1200 crank horsepower in twin configuration. Now just decide on exhaust a/r vs cubic inch or how responsive you want it to be. More cubes can get away with a bigger a/r. Smaller cubes will want to keep the a/r tight to reduce lag.
Remember that a turbo will not make more power than what the compressor map shows it capable of but it will also not make what the map shows it's capable of if you do not have enough flow on the exhaust side.
Once you've found a turbo or turbos capable of flowing what you need on the compressor side, take a look at the turbine. The turbine should be roughly the same size or larger than the compressor. This is a good indication of a well matched turbo. Again, when you see the turbine size as much smaller than the compressor this generally will not be a very efficient unit and will cause backpressure issues on a single and possible massive boost creep with twins.
There are always exceptions and the above info is just very basic. Many times if I think I've found a turbo I want to run in twin configuration I'll look online and see how well it's done with the 4 cylinder guys. They will extensively do back to back dyno tests with the smaller turbos so by reading those tests and viewing there dyno charts you can get an idea of how good the unit is.
For more reading, this is excellent-
http://www.turbobygarrett.com/turbob...Catalog_V4.pdf
08-22-2012, 10:40 PM
#217
wow, thanks for clearing up how to read the compressor map. I read that attachment and that is really helpful!
There is a site that has a calculator that looks like it may work. I did a sample 5.3 with twins and goal of 850hp. it calculates the following on the compressor map directly.
not sure how accurate it is, but fun to see how different combos and expectations for power don't fit on a given turbo.
and here the same exact combo with a single T88
There is a site that has a calculator that looks like it may work. I did a sample 5.3 with twins and goal of 850hp. it calculates the following on the compressor map directly.
not sure how accurate it is, but fun to see how different combos and expectations for power don't fit on a given turbo.
and here the same exact combo with a single T88
08-23-2012, 06:55 PM
#220
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In terms of turbo selection allow me to refer back to the original post " Set your goals first and then decide on components that will allow you to reach those goals"
It is good to look at other combos to see if what someone else has achieved is what you want to achieve. Did it make enough power? Where is peak torque on the dyno graph? Typically if you are looking at a dyno graph of a manual car or auto with locked converter, peak torque will occur right around where it hits peak boost.
IMO, most combos that are a good trade-off between being responsive in normal driving situations but also able to make good power up top will hit peak boost/torque in the 4300-4500rpm range. If a combo can hit peak boost at a lower rpm than that you will have much more low rpm response at the expense of high rpm power. If it makes peak boost/torque much higher than that and you are trading low/mid range response for high rpm power. (usually).
I say usually because some combos with an unusually large exhaust A/R or just an oversized turbo(s) altogether may just be leaving low and midrange on the table for no gains up top.
Some basics on compressor maps. If you want to look through them, remember that roughly 10lbs/min = 100hp. So for example lets take a look at a Garrett GT3582R
As you can see, it's capable of roughly a bit over 60lbs/min maxed out which would be equal to around 1200 crank horsepower in twin configuration. Now just decide on exhaust a/r vs cubic inch or how responsive you want it to be. More cubes can get away with a bigger a/r. Smaller cubes will want to keep the a/r tight to reduce lag.
Remember that a turbo will not make more power than what the compressor map shows it capable of but it will also not make what the map shows it's capable of if you do not have enough flow on the exhaust side.
Once you've found a turbo or turbos capable of flowing what you need on the compressor side, take a look at the turbine. The turbine should be roughly the same size or larger than the compressor. This is a good indication of a well matched turbo. Again, when you see the turbine size as much smaller than the compressor this generally will not be a very efficient unit and will cause backpressure issues on a single and possible massive boost creep with twins.
There are always exceptions and the above info is just very basic. Many times if I think I've found a turbo I want to run in twin configuration I'll look online and see how well it's done with the 4 cylinder guys. They will extensively do back to back dyno tests with the smaller turbos so by reading those tests and viewing there dyno charts you can get an idea of how good the unit is.
For more reading, this is excellent-
http://www.turbobygarrett.com/turbob...Catalog_V4.pdf
It is good to look at other combos to see if what someone else has achieved is what you want to achieve. Did it make enough power? Where is peak torque on the dyno graph? Typically if you are looking at a dyno graph of a manual car or auto with locked converter, peak torque will occur right around where it hits peak boost.
IMO, most combos that are a good trade-off between being responsive in normal driving situations but also able to make good power up top will hit peak boost/torque in the 4300-4500rpm range. If a combo can hit peak boost at a lower rpm than that you will have much more low rpm response at the expense of high rpm power. If it makes peak boost/torque much higher than that and you are trading low/mid range response for high rpm power. (usually).
I say usually because some combos with an unusually large exhaust A/R or just an oversized turbo(s) altogether may just be leaving low and midrange on the table for no gains up top.
Some basics on compressor maps. If you want to look through them, remember that roughly 10lbs/min = 100hp. So for example lets take a look at a Garrett GT3582R
As you can see, it's capable of roughly a bit over 60lbs/min maxed out which would be equal to around 1200 crank horsepower in twin configuration. Now just decide on exhaust a/r vs cubic inch or how responsive you want it to be. More cubes can get away with a bigger a/r. Smaller cubes will want to keep the a/r tight to reduce lag.
Remember that a turbo will not make more power than what the compressor map shows it capable of but it will also not make what the map shows it's capable of if you do not have enough flow on the exhaust side.
Once you've found a turbo or turbos capable of flowing what you need on the compressor side, take a look at the turbine. The turbine should be roughly the same size or larger than the compressor. This is a good indication of a well matched turbo. Again, when you see the turbine size as much smaller than the compressor this generally will not be a very efficient unit and will cause backpressure issues on a single and possible massive boost creep with twins.
There are always exceptions and the above info is just very basic. Many times if I think I've found a turbo I want to run in twin configuration I'll look online and see how well it's done with the 4 cylinder guys. They will extensively do back to back dyno tests with the smaller turbos so by reading those tests and viewing there dyno charts you can get an idea of how good the unit is.
For more reading, this is excellent-
http://www.turbobygarrett.com/turbob...Catalog_V4.pdf