Dead horse beating! S475 vs s480 vs 7875 vs 7883
02-09-2023, 02:54 PM
#21
This is one of those typical posts we see where someone wants to have their cake and eat it too. You can’t have 800hp and a 1000hp goals because the turbo spec’d well for an 800hp goal isn’t’ the same turbo you’d spec for a 1000hp goal. Then we throw in the WHP figure which really throws things off. As you can make 1200+ at the crank and only 1000 at the wheels. Then we toss in T4 preference. Which limits you again. Then you want a snappy responsive turbo setup with a mild base motor… that also makes eye ball sucking HP.
Unfortunately, we can’t have it all. As with anything “performance” it’s a give and take.. If you have a relatively low output base motor and need big boost to hit your goal. You need a big turbo, which won’t be super responsive. I’d also like to say that you don’t need or want a "super responsive" 800-1000whp car on the street as it won’t do anything… quick response is useless, if you can’t use it. And if you have to use several different traction control strategies to dumb the power down to make it useable… what is the benefit of lightening quick response?
With an automatic trans and a T-brake, the “spool” time is 90% in the converter and tune. For a street strip toy raced from a stop, you can spool dammed near anything with the right tune and converter. I spool twin .96 T4 78/75s with a small cam only 5.3, very easily. Hit my peak boost and target boost is within a second after I release the brake. What more does anyone need?
I’m not a fan of T4’s or small wheel turbos at all with an 800 or a 1000hp goal. Zero reason to limit yourself. I’d suggest the same T6 87/96 exh wheel with an 800 or 1000hp goal. S475 for the 800 and S480 for the 1000. The other confusing thing is… who’s turbos are we talking about? A tweaked out Forced Inductions S400 based turbo vs A VSR or even a cast genuine BORG will all perform differently.
If you want a responsive quick car for the street I’d run a box stock T6 1.32 S475 with the 87/96 wheel and be done. That turbo has made 900whp+ and is more responsive than the S480. If you are super worried about response, get the optional 1.10 T6 housing. If you want 1000whp, go with the S480 and live with the response. Again, once your up on the brake… who cares?
Unfortunately, we can’t have it all. As with anything “performance” it’s a give and take.. If you have a relatively low output base motor and need big boost to hit your goal. You need a big turbo, which won’t be super responsive. I’d also like to say that you don’t need or want a "super responsive" 800-1000whp car on the street as it won’t do anything… quick response is useless, if you can’t use it. And if you have to use several different traction control strategies to dumb the power down to make it useable… what is the benefit of lightening quick response?
With an automatic trans and a T-brake, the “spool” time is 90% in the converter and tune. For a street strip toy raced from a stop, you can spool dammed near anything with the right tune and converter. I spool twin .96 T4 78/75s with a small cam only 5.3, very easily. Hit my peak boost and target boost is within a second after I release the brake. What more does anyone need?
I’m not a fan of T4’s or small wheel turbos at all with an 800 or a 1000hp goal. Zero reason to limit yourself. I’d suggest the same T6 87/96 exh wheel with an 800 or 1000hp goal. S475 for the 800 and S480 for the 1000. The other confusing thing is… who’s turbos are we talking about? A tweaked out Forced Inductions S400 based turbo vs A VSR or even a cast genuine BORG will all perform differently.
If you want a responsive quick car for the street I’d run a box stock T6 1.32 S475 with the 87/96 wheel and be done. That turbo has made 900whp+ and is more responsive than the S480. If you are super worried about response, get the optional 1.10 T6 housing. If you want 1000whp, go with the S480 and live with the response. Again, once your up on the brake… who cares?
Completely different type of power band though. The turbo motors relatively low power NA… Esp if you want it tame and quiet as you suggest. Then they get into boost and power doubles (or more) in about 1-2 seconds. So it shocks the crap outa the tire. Which is why even a 600hp “snappy” turbo setup is brutal on the street. Figure you are over doubling the power in a very short time. Thats is hard on traction. It’s like spraying your 600hp big block with a 600 shot and expecting to stick the tire on the street.
In my experience, dyno queen BS numbers don’t mean much. My 800ish HP car (I go by weight and trap speed) has out trapped and out Et’d 1000+ dyno queens many many times. Figure at 3200lbs 800ish whp (which is closer to 900ish at the crank) is enough to run 8’s. Personally I think 8 second cars make really crappy street toys. They are just too damn quick and unstable. Too much can go wrong. A large truck will never be “Stabile” at that acceleration/speed. I had mine all dialed in pulling tons of timing and running boost by speed etc. By the time I hit 50ish I could ramp all the power in over about 3 seconds and it would hook on the street. assuming the street was perfect. But hit one little gravel patch or liquid of any sort and you’re screwed.
I don’t mean to be the old guy telling people they can’t race on the street. Just throwing out my personal experience. If you decide to go T4. I’d get the housing machined for the larger 87/96 wheel. You really limit yourself with the smaller exh wheel on the T4 S475. (its also more expensive)
In my experience, dyno queen BS numbers don’t mean much. My 800ish HP car (I go by weight and trap speed) has out trapped and out Et’d 1000+ dyno queens many many times. Figure at 3200lbs 800ish whp (which is closer to 900ish at the crank) is enough to run 8’s. Personally I think 8 second cars make really crappy street toys. They are just too damn quick and unstable. Too much can go wrong. A large truck will never be “Stabile” at that acceleration/speed. I had mine all dialed in pulling tons of timing and running boost by speed etc. By the time I hit 50ish I could ramp all the power in over about 3 seconds and it would hook on the street. assuming the street was perfect. But hit one little gravel patch or liquid of any sort and you’re screwed.
I don’t mean to be the old guy telling people they can’t race on the street. Just throwing out my personal experience. If you decide to go T4. I’d get the housing machined for the larger 87/96 wheel. You really limit yourself with the smaller exh wheel on the T4 S475. (its also more expensive)
I could see your point on how you are doubling power "shocking" the drivetrain/tires.
I don't necessarily want an 8 second pass, just enough to beat my buddy's chevelle, which I think 800hp can do. He hasn't ran it yet, but it feels very similar to my camaro but also have some of my cake(quiet/mild) and eat it too(the extra power of boost).
I figure this engine makes 450 horse at the crank. If I can add a little more than an additional atmosphere(15psi) I should be able to get to 800rwhp(If I don't get that but make somewhere near it I'd be happy).
I am leaning toward that summit s475. I keep coming back to it.
02-09-2023, 03:10 PM
#23
Without some sort of boost or timing control. The problem is that boost comes in hard. It doesn’t generally start at say 1psi and slowly ramp to 15 by redline… It basically makes no boost to say 3-4k, then once it lights off, it makes all the boost within a second or so. Which is why some form of boost control VS speed or a slow timing ramp is needed on the street.
02-10-2023, 01:17 AM
#24
I have an LY6 with a 7875 and it’s a great combo for the street. Boost is always there when you want it and with a boost controller you can tame it down or have 15-20lbs instantly. Admittedly you will not be able to hook at that level it just comes on to quick but for me that’s the best part.
02-10-2023, 10:07 AM
#25
I have an LY6 with a 7875 and it’s a great combo for the street. Boost is always there when you want it and with a boost controller you can tame it down or have 15-20lbs instantly. Admittedly you will not be able to hook at that level it just comes on to quick but for me that’s the best part.
I do like the idea of the 7875 coming on like that.
02-10-2023, 10:53 AM
#26
i have a 7875 that had the .96 housing. It spooled really quick. Then i put the 1.25 housing with 4" outlet (I'm using 3.5" pipe) and it lost a little bit of spool, so i messed with the tune and gained it back. It pulls much harder on top end with really no loss of low.
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07GTLS (02-10-2023)
02-10-2023, 11:10 AM
#27
I can make up your mind for you. Is this a race car/truck? if yes, go big. If no....get the 7875 gen 3. It won't be a dog, it'll spool quickly and make more than enough power to put a smile on your face. It'll be plenty enough to put it on your buddy too.
i have a 7875 that had the .96 housing. It spooled really quick. Then i put the 1.25 housing with 4" outlet (I'm using 3.5" pipe) and it lost a little bit of spool, so i messed with the tune and gained it back. It pulls much harder on top end with really no loss of low.
i have a 7875 that had the .96 housing. It spooled really quick. Then i put the 1.25 housing with 4" outlet (I'm using 3.5" pipe) and it lost a little bit of spool, so i messed with the tune and gained it back. It pulls much harder on top end with really no loss of low.
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Kfxguy (02-11-2023)
02-10-2023, 12:17 PM
#30
I can make up your mind for you. Is this a race car/truck? if yes, go big. If no....get the 7875 gen 3. It won't be a dog, it'll spool quickly and make more than enough power to put a smile on your face. It'll be plenty enough to put it on your buddy too.
i have a 7875 that had the .96 housing. It spooled really quick. Then i put the 1.25 housing with 4" outlet (I'm using 3.5" pipe) and it lost a little bit of spool, so i messed with the tune and gained it back. It pulls much harder on top end with really no loss of low.
i have a 7875 that had the .96 housing. It spooled really quick. Then i put the 1.25 housing with 4" outlet (I'm using 3.5" pipe) and it lost a little bit of spool, so i messed with the tune and gained it back. It pulls much harder on top end with really no loss of low.
02-10-2023, 01:09 PM
#31
lol….I’m reading it now….I found it before you said something. I love those kinds of threads.
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ddnspider (02-10-2023)
02-10-2023, 03:47 PM
#33
I can make up your mind for you. Is this a race car/truck? if yes, go big. If no....get the 7875 gen 3. It won't be a dog, it'll spool quickly and make more than enough power to put a smile on your face. It'll be plenty enough to put it on your buddy too.
i have a 7875 that had the .96 housing. It spooled really quick. Then i put the 1.25 housing with 4" outlet (I'm using 3.5" pipe) and it lost a little bit of spool, so i messed with the tune and gained it back. It pulls much harder on top end with really no loss of low.
i have a 7875 that had the .96 housing. It spooled really quick. Then i put the 1.25 housing with 4" outlet (I'm using 3.5" pipe) and it lost a little bit of spool, so i messed with the tune and gained it back. It pulls much harder on top end with really no loss of low.
Also the difference between a .96 and a 1.24 isn't much. Not even noticeable by the "seat of your pants".
Check out ls1curts build on this forum to see what a cast Borg T4 S475 is capable of. The T6 will perform even better. I don't see 78/75's do that... (again just saying I'm not aware of any) And dynos are great for tuning and all... but I like to see the car back it up at the track with actual numbers.
Much like Matt Happel's video where they show the switch from a T4 78/75 to an S480 T6. They improved the spool time over the T4 turbo, and gained over 100hp across the board at the same boost.
https://ls1tech.com/forums/forced-in...lsx-notch.html
02-10-2023, 04:34 PM
#34
Where's the data that shows the gen3 78/75 is any better than a box stock S475? The S475 (to my knowledge) has been quicker, spools quicker, and makes more power. Not saying there haven't been 78/75s that have done better... just that I'm not aware of any.
Also the difference between a .96 and a 1.24 isn't much. Not even noticeable by the "seat of your pants".
Check out ls1curts build on this forum to see what a cast Borg T4 S475 is capable of. The T6 will perform even better. I don't see 78/75's do that... (again just saying I'm not aware of any) And dynos are great for tuning and all... but I like to see the car back it up at the track with actual numbers.
Much like Matt Happel's video where they show the switch from a T4 78/75 to an S480 T6. They improved the spool time over the T4 turbo, and gained over 100hp across the board at the same boost.
https://ls1tech.com/forums/forced-in...lsx-notch.html
Also the difference between a .96 and a 1.24 isn't much. Not even noticeable by the "seat of your pants".
Check out ls1curts build on this forum to see what a cast Borg T4 S475 is capable of. The T6 will perform even better. I don't see 78/75's do that... (again just saying I'm not aware of any) And dynos are great for tuning and all... but I like to see the car back it up at the track with actual numbers.
Much like Matt Happel's video where they show the switch from a T4 78/75 to an S480 T6. They improved the spool time over the T4 turbo, and gained over 100hp across the board at the same boost.
https://ls1tech.com/forums/forced-in...lsx-notch.html
data? I have no data and I need no data to point out the fact that we all know, you can’t go wrong with a 7875 for most not too radical street combos. The 1.25 housing is way larger and obviously flows better. I went from a 3” to a 3.5” down pipe and without a doubt I could feel a difference.
How you would think that it would not make a noticeable power difference makes me scratch my head. The s480 will make good power too, but it’s much larger and harder to package under the hood. All you’re doing is going to confuse the OP even further and make it even more difficult to choose. You’re recommending a t6 frame turbo which he stated he’d rather not use if he DIDN’T have to.
He also mentioned he’d rather give up his power goal for something that is more fun to drive.
I’ve seen numerous cars in the 9’s not maxed out on a regular 7875. One with an upgraded exhaust housing has even more potential. Since you mention Matt
he made 821rwhp with a gen 1 7875, 6.0, 4l80e, e85. With the gen 2 (op is looking at even better gen 3) he made 912rwhp running out of injector.
02-10-2023, 06:03 PM
#35
T
If you want a responsive quick car for the street I’d run a box stock T6 1.32 S475 with the 87/96 wheel and be done. That turbo has made 900whp+ and is more responsive than the S480. If you are super worried about response, get the optional 1.10 T6 housing. If you want 1000whp, go with the S480 and live with the response. Again, once your up on the brake… who cares?
If you want a responsive quick car for the street I’d run a box stock T6 1.32 S475 with the 87/96 wheel and be done. That turbo has made 900whp+ and is more responsive than the S480. If you are super worried about response, get the optional 1.10 T6 housing. If you want 1000whp, go with the S480 and live with the response. Again, once your up on the brake… who cares?
The OP is going to run into some differences as far as the wheel options go, and just wanted to see if you'd give a brief explanation of the effects it has.
To the OP, I agree with Forced. I have never had a HP goal with my cars, only a track goal. That and then considering it's use are the two important things, and how much tolerance you have for an uncomfortable car because it's always a trade off.
02-10-2023, 08:04 PM
#36
How about this video. 2.4 4cyl, vs racing 7875 gen2, 1.25ar, made 588hp @ only 13psi.
4.8 ls, same turbo made 411hp before the turbo then made 805hp around 15psi. He even says it’ll make over 1000hp at higher boost.
what’s my point? It’s a super versatile turbo that will work well on a lot of stuff.
4.8 ls, same turbo made 411hp before the turbo then made 805hp around 15psi. He even says it’ll make over 1000hp at higher boost.
what’s my point? It’s a super versatile turbo that will work well on a lot of stuff.
02-11-2023, 11:36 AM
#37
data? I have no data and I need no data to point out the fact that we all know, you can’t go wrong with a 7875 for most not too radical street combos. The 1.25 housing is way larger and obviously flows better. I went from a 3” to a 3.5” down pipe and without a doubt I could feel a difference.
How you would think that it would not make a noticeable power difference makes me scratch my head. The s480 will make good power too, but it’s much larger and harder to package under the hood. All you’re doing is going to confuse the OP even further and make it even more difficult to choose. You’re recommending a t6 frame turbo which he stated he’d rather not use if he DIDN’T have to.
He also mentioned he’d rather give up his power goal for something that is more fun to drive.
I’ve seen numerous cars in the 9’s not maxed out on a regular 7875. One with an upgraded exhaust housing has even more potential. Since you mention Matt
he made 821rwhp with a gen 1 7875, 6.0, 4l80e, e85. With the gen 2 (op is looking at even better gen 3) he made 912rwhp running out of injector.
How you would think that it would not make a noticeable power difference makes me scratch my head. The s480 will make good power too, but it’s much larger and harder to package under the hood. All you’re doing is going to confuse the OP even further and make it even more difficult to choose. You’re recommending a t6 frame turbo which he stated he’d rather not use if he DIDN’T have to.
He also mentioned he’d rather give up his power goal for something that is more fun to drive.
I’ve seen numerous cars in the 9’s not maxed out on a regular 7875. One with an upgraded exhaust housing has even more potential. Since you mention Matt
he made 821rwhp with a gen 1 7875, 6.0, 4l80e, e85. With the gen 2 (op is looking at even better gen 3) he made 912rwhp running out of injector.
The thing is I've run a lot of housing combos on the turbos mentioned here. Have you? I have experience with my cars and many others. I know what they do and have data logs on them. You looking at a physically larger housing and stating it flows "better" says very little. Better compared to what? Sure, it flows better, but how much? Is it worth the cost vs performance gain to switch? I have pushed S400 chassis turbos to the limit. Then changed housings alone and noticed very little change in BP and very small power increases. Sure they make a difference, But IMO for the common street/strip guy, it's not worth the time/money to do so in most cases. I've run a 1.10 t4 1.25 t4 as well as 1.10 t6 and 1.32 t6 and 1.58 T6 on S400 series turbos... As well as .68 78/75s and .96 78/75s. What I'm saying is if you actually look at the data logs, you will find there is VERY little change in total BP, power production, or spool with a moderate housing change alone. Changing the Wheels is where big things happen.
I'm not sure why you bring up down pipes, that wasn't being discussed. I run 4" or larger and very short lengths on all my stuff S400 setups. DP size has never been a factor in my comparisons they all had plenty of breathing room.
You can't say "you can't go wrong with a 78/75." If you want 800+ whp. and there's a turbo that does it better, for less... how is a 78/75 a better choice? What you mean is that you run one, and you like it. That's great... I have no problem with that. But until you have back to back time slips and data logs with the other chargers we are discussing, then its all opinion. Quoting a dyno number gives no comparison. Would the same car that made XXX on a 78/75 made more with An S475? would it of spooled quicker? If you dont' have time slips with back to back comparisons we don't know if the response and driver pressure differences either. So that data is useless. Then throw in that dyno's are simply a tuning tool. I can't count the number of "1000+ whp" dyno queens I've out trapped and ran at the track.
The 78/75 is flawed form the start due to it having an under driven exh wheel. The exh. wheel should always be large than the compressor. Not saying they can't work and work well in some applications. Hell, I run a pair of them on one of my cars. What I'm saying is for a single and the OP's goals there are better units at similar prices.
02-11-2023, 11:50 AM
#38
How about this video. 2.4 4cyl, vs racing 7875 gen2, 1.25ar, made 588hp @ only 13psi.
4.8 ls, same turbo made 411hp before the turbo then made 805hp around 15psi. He even says it’ll make over 1000hp at higher boost.
what’s my point? It’s a super versatile turbo that will work well on a lot of stuff.
4.8 ls, same turbo made 411hp before the turbo then made 805hp around 15psi. He even says it’ll make over 1000hp at higher boost.
what’s my point? It’s a super versatile turbo that will work well on a lot of stuff.
02-11-2023, 11:57 AM
#39
Forcefed, would you talk just briefly about the performance characteristics/difference between a T6 1.32 S475, 87/96 wheel and a T6 S475 1.32AR 96/88, which is what I have. I jumped the gun a little on mine. I am running a T brake and 4500 converter or whatever will work best at the track and plan to run it to 6800 or so.
The OP is going to run into some differences as far as the wheel options go, and just wanted to see if you'd give a brief explanation of the effects it has.
To the OP, I agree with Forced. I have never had a HP goal with my cars, only a track goal. That and then considering it's use are the two important things, and how much tolerance you have for an uncomfortable car because it's always a trade off.
The OP is going to run into some differences as far as the wheel options go, and just wanted to see if you'd give a brief explanation of the effects it has.
To the OP, I agree with Forced. I have never had a HP goal with my cars, only a track goal. That and then considering it's use are the two important things, and how much tolerance you have for an uncomfortable car because it's always a trade off.
Borg calls it an 87/96. So that what I use. Borg also lists the larger diameter first. Which is back wards from the rest of the turbo world. The smaller diameter is the EXH wheel exit diameter and what most manufacturers use. The "big exh wheel" borg S400's are an 87mm exducer. Aftermarket wheels can be much larger. So the "big" S475 is a 75/87 The little t4 S475 is a 75/75.
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07GTLS (02-11-2023)
02-11-2023, 12:08 PM
#40
Don't need data huh? That's a pretty ignorant statement for anything to do with cars and performance. Of course you want the data, its the most important thing in racing.
The thing is I've run a lot of housing combos on the turbos mentioned here. Have you? I have experience with my cars and many others. I know what they do and have data logs on them. You looking at a physically larger housing and stating it flows "better" says very little. Better compared to what? Sure, it flows better, but how much? Is it worth the cost vs performance gain to switch? I have pushed S400 chassis turbos to the limit. Then changed housings alone and noticed very little change in BP and very small power increases. Sure they make a difference, But IMO for the common street/strip guy, it's not worth the time/money to do so in most cases. I've run a 1.10 t4 1.25 t4 as well as 1.10 t6 and 1.32 t6 and 1.58 T6 on S400 series turbos... As well as .68 78/75s and .96 78/75s. What I'm saying is if you actually look at the data logs, you will find there is VERY little change in total BP, power production, or spool with a moderate housing change alone. Changing the Wheels is where big things happen.
I'm not sure why you bring up down pipes, that wasn't being discussed. I run 4" or larger and very short lengths on all my stuff S400 setups. DP size has never been a factor in my comparisons they all had plenty of breathing room.
You can't say "you can't go wrong with a 78/75." If you want 800+ whp. and there's a turbo that does it better, for less... how is a 78/75 a better choice? What you mean is that you run one, and you like it. That's great... I have no problem with that. But until you have back to back time slips and data logs with the other chargers we are discussing, then its all opinion. Quoting a dyno number gives no comparison. Would the same car that made XXX on a 78/75 made more with An S475? would it of spooled quicker? If you dont' have time slips with back to back comparisons we don't know if the response and driver pressure differences either. So that data is useless. Then throw in that dyno's are simply a tuning tool. I can't count the number of "1000+ whp" dyno queens I've out trapped and ran at the track.
The 78/75 is flawed form the start due to it having an under driven exh wheel. The exh. wheel should always be large than the compressor. Not saying they can't work and work well in some applications. Hell, I run a pair of them on one of my cars. What I'm saying is for a single and the OP's goals there are better units at similar prices.
The thing is I've run a lot of housing combos on the turbos mentioned here. Have you? I have experience with my cars and many others. I know what they do and have data logs on them. You looking at a physically larger housing and stating it flows "better" says very little. Better compared to what? Sure, it flows better, but how much? Is it worth the cost vs performance gain to switch? I have pushed S400 chassis turbos to the limit. Then changed housings alone and noticed very little change in BP and very small power increases. Sure they make a difference, But IMO for the common street/strip guy, it's not worth the time/money to do so in most cases. I've run a 1.10 t4 1.25 t4 as well as 1.10 t6 and 1.32 t6 and 1.58 T6 on S400 series turbos... As well as .68 78/75s and .96 78/75s. What I'm saying is if you actually look at the data logs, you will find there is VERY little change in total BP, power production, or spool with a moderate housing change alone. Changing the Wheels is where big things happen.
I'm not sure why you bring up down pipes, that wasn't being discussed. I run 4" or larger and very short lengths on all my stuff S400 setups. DP size has never been a factor in my comparisons they all had plenty of breathing room.
You can't say "you can't go wrong with a 78/75." If you want 800+ whp. and there's a turbo that does it better, for less... how is a 78/75 a better choice? What you mean is that you run one, and you like it. That's great... I have no problem with that. But until you have back to back time slips and data logs with the other chargers we are discussing, then its all opinion. Quoting a dyno number gives no comparison. Would the same car that made XXX on a 78/75 made more with An S475? would it of spooled quicker? If you dont' have time slips with back to back comparisons we don't know if the response and driver pressure differences either. So that data is useless. Then throw in that dyno's are simply a tuning tool. I can't count the number of "1000+ whp" dyno queens I've out trapped and ran at the track.
The 78/75 is flawed form the start due to it having an under driven exh wheel. The exh. wheel should always be large than the compressor. Not saying they can't work and work well in some applications. Hell, I run a pair of them on one of my cars. What I'm saying is for a single and the OP's goals there are better units at similar prices.