TC78 Replacement
TC78 Replacement I need some ideas for potential replacements for the Turbonetics TC78. It has to have the same external dimensions so I don't have reconfigure the cooling system. Can anybody give me some ideas? I'm thinking about a PT7475 but it's a street car so some something that'll spool quick but still make power to 6000-6500. Any help would be greatly appreciated. Thanks!
yes how far have you pushed that tc78. I ran a tc78 on my 6.0 with a .96 housing and it ran 10.50s in my 3500# car. at 10# boost. there is no dought that I could have broke into the nines with it at a few more #s boost. it was a little restrictive upstairs but the fast spool will get the car moving out of the hole.
yes how far have you pushed that tc78. I ran a tc78 on my 6.0 with a .96 housing and it ran 10.50s in my 3500# car. at 10# boost. there is no dought that I could have broke into the nines with it at a few more #s boost. it was a little restrictive upstairs but the fast spool will get the car moving out of the hole.
yes how far have you pushed that tc78. I ran a tc78 on my 6.0 with a .96 housing and it ran 10.50s in my 3500# car. at 10# boost. there is no dought that I could have broke into the nines with it at a few more #s boost. it was a little restrictive upstairs but the fast spool will get the car moving out of the hole.
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i went 136+ mph @ 3600# and did 610 rwhp at 14.5# on a TC76 .96 AR maxed out. power just flat lined at about 5400
swapped to a 1.15 AR when I did the 4L80 and the power carries much better now. only have an eight mph comparison but went 106 mph with the t56 and .96 AR and 111 mph with the 4l80 and 1.15.
The new 7875 are the closest but are still larger so if clearance is ultra tight you will need to modify
swapped to a 1.15 AR when I did the 4L80 and the power carries much better now. only have an eight mph comparison but went 106 mph with the t56 and .96 AR and 111 mph with the 4l80 and 1.15.
The new 7875 are the closest but are still larger so if clearance is ultra tight you will need to modify
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7475 is a great budget alternative. I had it on my first set-up and now my friend is using it. He did 690 or so at 20 psi through an auto, 28's, and 9", on a Thompson 5.3, SAE. Little sucker can make some power.
When you say cooling system, are you referring to the turbo also being water cooled? If so that is something to consider as Precision only offers Oil-Only. Let me know and I can get you into an excellent drop-in upgrade for the very best price!!!
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It pulls harder than hell to right about 5400 then slows waaay down. I'm also running full exhaust and the pipe going from the bell-housing area to the trans tail-shaft is compression bent and horribly done. I'm just running straight 93, no meth and the turbo is just oil fed. I'm already running a 1.15 AR housing too, its a divided housing and my hot side flange is undivided so I don't know if that makes a difference. I'm only running 6 lbs. right now and the way it's acting I would not feel comfortable putting the 10 spring back in. The turbo sits about 3/4" away from the radiator so a larger compressor housing is out and I'm not standing up the radiator. I'm definitely installing a cutout under the driver floor board but a couple of my buddies don't think that'll help but I want it anyways lol. The turbo only has maybe 1,000 miles on it and its a ceramic ball bearing unit so I'm wondering what I could get for it.
It pulls harder than hell to right about 5400 then slows waaay down. I'm also running full exhaust and the pipe going from the bell-housing area to the trans tail-shaft is compression bent and horribly done. I'm just running straight 93, no meth and the turbo is just oil fed. I'm already running a 1.15 AR housing too, its a divided housing and my hot side flange is undivided so I don't know if that makes a difference. I'm only running 6 lbs. right now and the way it's acting I would not feel comfortable putting the 10 spring back in. The turbo sits about 3/4" away from the radiator so a larger compressor housing is out and I'm not standing up the radiator. I'm definitely installing a cutout under the driver floor board but a couple of my buddies don't think that'll help but I want it anyways lol. The turbo only has maybe 1,000 miles on it and its a ceramic ball bearing unit so I'm wondering what I could get for it.
Shoot me an email to: huronspeedproducts@gmail.com
I can get you exactly what you need!
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Thanks for the offer Superman but I don't have the coin to drop on a new turbo. I think I'm going to try and sell this one next month and see what I can find on the used market.
the tc78 is a better spooling street turbo. all things equal going from my tc78 to my s480/83/t4/1.25 . at the track with exactly the same tune it runs the same numbers. 10.50s at 130. now when I turn it up the 480 really brings it.
I did everything I could to make the same runs with both turbos.
93 no meth
11* timing
5500 shift point.
same launch 1.6 60' ect. ect.
all I learned is at that level I was not maxing my tc78 turbo.
I will be turning up to about 14 to 15# this fall and im running a progressive meth system so I might try a little more timing as well. shooting for 10 flat or so.
maybe a higher strung setup with more cam might have a bigger issue with the smaller turbo but my lq4 with a 206/212 duration cam does not seem to care.
try the dump first. what about the valve springs? at 6# your not really in the sweet spot of that turbo. mine was a 78/68 .96 with a 3.5 downpipe and felt good under 5800.
Last edited by yenkomike; Sep 14, 2015 at 07:15 PM.
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Featuring 6 different turbo kits for your F-body!
Check us out on Facebook at: www.facebook.com/HuronSpeed
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the tc78 is a better spooling street turbo. all things equal going from my tc78 to my s480/83/t4/1.25 . at the track with exactly the same tune it runs the same numbers. 10.50s at 130. now when I turn it up the 480 really brings it.
I did everything I could to make the same runs with both turbos.
93 no meth
11* timing
5500 shift point.
same launch 1.6 60' ect. ect.
all I learned is at that level I was not maxing my tc78 turbo.
I will be turning up to about 14 to 15# this fall and im running a progressive meth system so I might try a little more timing as well. shooting for 10 flat or so.
maybe a higher strung setup with more cam might have a bigger issue with the smaller turbo but my lq4 with a 206/212 duration cam does not seem to care.
try the dump first. what about the valve springs? at 6# your not really in the sweet spot of that turbo. mine was a 78/68 .96 with a 3.5 downpipe and felt good under 5800.
I did everything I could to make the same runs with both turbos.
93 no meth
11* timing
5500 shift point.
same launch 1.6 60' ect. ect.
all I learned is at that level I was not maxing my tc78 turbo.
I will be turning up to about 14 to 15# this fall and im running a progressive meth system so I might try a little more timing as well. shooting for 10 flat or so.
maybe a higher strung setup with more cam might have a bigger issue with the smaller turbo but my lq4 with a 206/212 duration cam does not seem to care.
try the dump first. what about the valve springs? at 6# your not really in the sweet spot of that turbo. mine was a 78/68 .96 with a 3.5 downpipe and felt good under 5800.
the tc78 is a better spooling street turbo. all things equal going from my tc78 to my s480/83/t4/1.25 . at the track with exactly the same tune it runs the same numbers. 10.50s at 130. now when I turn it up the 480 really brings it.
I did everything I could to make the same runs with both turbos.
93 no meth
11* timing
5500 shift point.
same launch 1.6 60' ect. ect.
all I learned is at that level I was not maxing my tc78 turbo.
I will be turning up to about 14 to 15# this fall and im running a progressive meth system so I might try a little more timing as well. shooting for 10 flat or so.
maybe a higher strung setup with more cam might have a bigger issue with the smaller turbo but my lq4 with a 206/212 duration cam does not seem to care.
try the dump first. what about the valve springs? at 6# your not really in the sweet spot of that turbo. mine was a 78/68 .96 with a 3.5 downpipe and felt good under 5800.
I did everything I could to make the same runs with both turbos.
93 no meth
11* timing
5500 shift point.
same launch 1.6 60' ect. ect.
all I learned is at that level I was not maxing my tc78 turbo.
I will be turning up to about 14 to 15# this fall and im running a progressive meth system so I might try a little more timing as well. shooting for 10 flat or so.
maybe a higher strung setup with more cam might have a bigger issue with the smaller turbo but my lq4 with a 206/212 duration cam does not seem to care.
try the dump first. what about the valve springs? at 6# your not really in the sweet spot of that turbo. mine was a 78/68 .96 with a 3.5 downpipe and felt good under 5800.
I may Superman and I know your prices are good, I just checked out a Turbonetics 7675 on your website and if I can get $1,000 or $900 for the TC78 I'll be giving you a ring. ; ) Is that what you'd suggest?
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I would be curious how the tune looks if it's falling off that hard like you say. What is the AFR doing up at that rev? Could be a part of the fuel being too much or not enough timing. At a point there is the matter of determining motor life vs performance.
You could be running into some back pressure issues or it could even be that you are use to the power. Running my car at the wastegate pressure with the eboost 2 it doesn't have the same umph as when I turn it up to 9 pounds or even 12. Then if I open the cutout things get really nasty.
I did think something was wrong with my G8 after driving the TA for a while, then wife drove the TA for a bit then the G8 and thought something was wrong, and that's how I ended up with a LSA blower on in a weekend.
You could be running into some back pressure issues or it could even be that you are use to the power. Running my car at the wastegate pressure with the eboost 2 it doesn't have the same umph as when I turn it up to 9 pounds or even 12. Then if I open the cutout things get really nasty.
I did think something was wrong with my G8 after driving the TA for a while, then wife drove the TA for a bit then the G8 and thought something was wrong, and that's how I ended up with a LSA blower on in a weekend.
Well and now that you say that Rawr I'm not sure the engine would live much longer with a bigger turbo. It's probably pretty close to 500 rwhp and it keeps me shifting at 5,500 rpm so this might be the best compromise between performance and longevity. I think I'll reach out to my tuner again and plan on installing a cutout, if your got nasty with it open I'd be hard pressed to believe it wouldn't be beneficial with my setup.