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Discussion Starter #1
im planning on doing a huge turbo upgrade. was thinking of a T-88, but its going to be my street car and im worried about the lag. is there any way to upgrade the twin turbo setup with two diffrent size turbos on diffrent boost levels?
like for instance a T-72 and T-68 under the same hood. the best of both worlds, fast spool up and endless power.
SOMEONE HELP!!!
 

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afd

from what I read upgrading the stock twins is not good as far as cost and reliability, but why not get the sp63..spools quicker than the stockers if I remember right and can give you good amounts of horsepower
 

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I think you are confused

Sounds to me like you are a little confused on the turbocharger designations.

A T-88 is not bigger than a T-72!

ok here is how it works.....the numbers are meaningless unless you know what context you are comparing them with.

a T-88 is a mitsubishi turbo, and all it means it that it is using a TD08 turbine housing and a TD08 compressor housing. It is their big dog....but not all T-88s are equal. It is just a family designation. Same goes for a T-78 , it is a Td07 exhaust with a TD08 compressor housing. although for all intents and purposes the ones you guys get are identicle, they are a generic model......but they do not have to be. one T78 may have a completely different sized turbine or compressor wheel than another T78 or T88. anyways....

Turbonetics ....they designate their turbos by the actual compressor wheel diameter in milimeters. (this is a far better way..it really gets you in the ballpark) A T-72 is a big turbo....real big! SW just ran 150mph on one with a 75shot.

the T68 is a new one to me....I did not find it in the turbonetics catalog (maybe it is a new one ?????) anyhow that would also be a monster. I think a T66 is about the limit of a truely streetable turbo on these cars. sure you can go bigger....but you really start sacrificing drivability.


as for as you using two turbos that size!?!?!? no way man.....no F'ing way. It would be drag only....and you would need at least 150shot to spool them.

now different sized turbos. this presents a real engineering problem (first of all can you name one manuf. that has ever done this?) I am not aware of any car with different size turbos....sure they have sequential...but they are identicle turbos, hence the name "twin".

The problem is that you get unequal backpressures. A turbo that has more rotating mass (lets go ahead and assume that they have the same turbine wheel for simplicity sake) would take more pressure to spool. So if you had a T72 and a T68 most of the pressure would try to escape through the easier to spool T68....exhaust tries to take the easiest path!! so what would happen is that you would just end up spinning the HELL out of the lighter turbo......the bigger turbo would never get in its efficiency range and the smaller one would be spun way past it.



this is just a bad idea all around. :D


I could go on....but I think I made my point.
 

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"Philzilla"
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Re: I think you are confused

Grandnat said:
...now different sized turbos.The problem is that you get unequal backpressures...so what would happen is that you would just end up spinning the HELL out of the lighter turbo......the bigger turbo would never get in its efficiency range and the smaller one would be spun way past it.
...not only that, but if you ever did get that bigger turbo spun up, it would probably outflow the smaller so much that the smaller one would be forced into spinning backwards! I very much agree: unequal sized turbos is a bad, bad idea.
 
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Discussion Starter #5
it would be better to just buy 2 smaller-sized turbos. the T04S04 .51 would be perfect for this. one they would build about 940 hp so be ready to pay a LOT of money for a clutch and fuel system that can support that much. that would be one hell of a car. like they said though, with that much hp you loose drivability. there arent any good daily driver clutches that support that much hp anyways. the best thing to do for an everyday car is go with a turbo that will build about 700 or less hp. just my thoughts though, they dont have to be yours too.
 
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Discussion Starter #6
A T-88 is not bigger than a T-72
The T88 is larger than the T72, in the context of the Greddy-packaged T88 vs. a T72 with an appropriately matched exhaust side and A/R.

SW just ran 150mph on one with a 75shot.
He has a 100 shot in that car.


I think a T66 is about the limit of a truely streetable turbo on these cars. sure you can go bigger....but you really start sacrificing drivability.
This is entirely subjective. To many people, a T66 is way too big, while to others, a T72 is not a problem. My turbo setup is larger than that, and I drive it to work every day, and it is fine by me.

It is extremely difficult to say ahead time what will fit your needs. A T64 or T66 is a good median turbo, and with that basic setup kit you can size up or down with a minimum of cost.
 

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Walser said:


The T88 is larger than the T72, in the context of the Greddy-packaged T88 vs. a T72 with an appropriately matched exhaust side and A/R.


I should have said not necessarily bigger.

the truth is that both turbos are 1000hp capable. I have a friend that makes 830 RWHP in his buick with one with no nitrous. SW made over 800rwhp also (I do not know if that was with nitrous or not) but either way thats 1000 fwhp.

the point I was making was "don't let the numbers fool ya!!!" a greddy T78 is dffinately not bigger than a T76!!!!


catch my drift?


He has a 100 shot in that car.


I might have heard some misinformation...I have heard 3 different answers now.

"SW's TurboImports.com/Performance-Motorsports T72 Supra shocked the import world by running a 150.00 mph trap speed on a stock bottom end. The head has NEVER been off this car. This run was made on high boost and an small 70hp shot of NOS. "



This is entirely subjective. To many people, a T66 is way too big, while to others, a T72 is not a problem. My turbo setup is larger than that, and I drive it to work every day, and it is fine by me.

It is extremely difficult to say ahead time what will fit your needs. A T64 or T66 is a good median turbo, and with that basic setup kit you can size up or down with a minimum of cost.


I think it was understood that that was my opinion... I even said "sure you can go bigger...." I think by most peoples standard that a T66 is getting close to what is considered a true street turbo.... but, it is anyones opinion.
 
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Discussion Starter #8
Who is running the biggest turbo on a daily driven auto?
 
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Discussion Starter #9
Re: I think you are confused

Grandnat said:
Sounds to me like you are a little confused on the turbocharger designations.

A T-88 is not bigger than a T-72!

ok here is how it works.....the numbers are meaningless unless you know what context you are comparing them with.

not quite........

the turbos im refering to are all greddy produced turbos and the T-88 is gigantic compared to the T-72
**I REPEAT I NEED A TURBO EXPERT**
 
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Discussion Starter #10
also, if i went with two smaller turbos say two T_62's would that replace the stock setup with no problems?
 

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I just want to add one thing. The larger the turbo the lower amount of backpressure between the turbo and the engine. Thus, a smaller engine,such as the 2JZGTE, will take longer to spool the turbo due to higher rotational mass, and less pressure to exert force on that mass. That is why many bigger turbo systems don't work well on the Auto's, unless you add N2O or some other way of make the engine rev faster. If you lower the rotational mass through lighter materials you potentially could run a larger diameter turbo and the lag sacrifices would be much more minimal. The racing applications all use titanium turbines, on the compressor, and exhaust side. This helps minimize turbo lag for faster spool up with larger turbos. This way they can make more power through higher airflow. If you took two t62 and put them together you would effectively destroy all backpressure between the motor and the turbo and would never be able to get the turbo's to spool with the auto. although you might be able to do it with a 6spd, but that is also highly unlikely. If you want a real life experience, do a TTC mod on your stockers and try to launch the car. Now imagine that lag quadrupled and that's the effect you would get from to t62's. Unless your gonna go for smaller twins,like what HKS packages in the 2835 kit I would forget about the "BIG" twin idea. Unless, your prepared to have a fully built motor, used just for drag racing. But then you lost your streetability. I analyzing for my 93 Auto, a T68 or spending some bucks and purchasing a T72 with titanium components.

Sorry for the long post,

Jesse Bergman
 

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BPUed said:
I just want to add one thing. The larger the turbo the lower amount of backpressure between the turbo and the engine. Thus, a smaller engine,such as the 2JZGTE, will take longer to spool the turbo due to higher rotational mass, and less pressure to exert force on that mass. That is why many bigger turbo systems don't work well on the Auto's, unless you add N2O or some other way of make the engine rev faster. If you lower the rotational mass through lighter materials you potentially could run a larger diameter turbo and the lag sacrifices would be much more minimal. The racing applications all use titanium turbines, on the compressor, and exhaust side. This helps minimize turbo lag for faster spool up with larger turbos. This way they can make more power through higher airflow. If you took two t62 and put them together you would effectively destroy all backpressure between the motor and the turbo and would never be able to get the turbo's to spool with the auto. although you might be able to do it with a 6spd, but that is also highly unlikely. If you want a real life experience, do a TTC mod on your stockers and try to launch the car. Now imagine that lag quadrupled and that's the effect you would get from to t62's. Unless your gonna go for smaller twins,like what HKS packages in the 2835 kit I would forget about the "BIG" twin idea. Unless, your prepared to have a fully built motor, used just for drag racing. But then you lost your streetability. I analyzing for my 93 Auto, a T68 or spending some bucks and purchasing a T72 with titanium components.

Sorry for the long post,

Jesse Bergman
Yes but you must remember a larger turbo doesn't have to spin as fast to produce the same boost. Maybe Darren or someone can comment of the spool-up time between larger and smaller turbos. Lighter materials will help the turbo spool faster (but not sooner).

Note I am talking about _lag_ here, not boost threashold. The boost threashold is the RPM where the turbo starts to make meaningfull boost, and is almost entirely defined by exhaust side of the turbo. Look at the T78 and T88. Same compressor side, but the T88 has a TD08 exhaust housing and wheel, so it spools 400 rpm later.

However, these two turbos have the same rotational mass and bearing losses, so I'd imagine the lag is the same. (At least, this is lag as how Corky Bell defines it in his book Maximum Boost).
 

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When I refer to faster spool up, I am not indicating that the turbo come on line sooner in the rpm band. But the engine will rev faster, there for the time frame that it takes for the turbo to come on line will be faster, thus you have a faster spool up time. Correct me if I'm wrong but that is how I define spool up time.
 
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Discussion Starter #14
one more question

lets say i went with the T-88 what are a couple things i could do, besides changing the turbine and compressor wheels, to speed up the spooling of the turbo.

:) thanks for all your help:)
 

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Re: Re: I think you are confused

supraholic'94tt said:

not quite........

the turbos im refering to are all greddy produced turbos and the T-88 is gigantic compared to the T-72
**I REPEAT I NEED A TURBO EXPERT**

The T72 is a turbonetics turbo. Greddy does not make a T72 as far as I know.


a T88 is not HUGE compared to a T72 (it may be bigger but not huge.). ready my post. the numbers greddy uses to measure turbo size are not the same numbers turbonetics use.

does anyone have a compressor map on a T88, I would like to see just how big it is compared to a T72.

I may net be an expert but I sure as hell know why you cannot use two diffent sized turbos...and I also know a few things about turbos in general...like that a T88 does not mean it has an 88mm compressor wheel!!!
 

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ok it looks like the T88 is a 900-1000rwhp turbo

and the T72 (which is bigger than the T78)is capable of up to ~900rwhp.


they are compareable turbos......not a HUGE difference.
 

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What Down Pipe is used with the Non greddy T78

What Down Pipe is used with the non greddy T78= TD07/TD08? I have it and its not a 4 bolt. What will fit? Its model number TD07-18A TD07 turbine with TD08 compressor
 

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Well sir, you could try and run a twin boost compounding setup. Geta 7:1 Built block and some race gas, and run 40-50 psi. You could run two different sized turbos then, but Id suggest trolling some diesel forums for that info :}
Although, somone who knows so little about, well his car, like you supraholic... Suggesting a possible Twin T66 setup on a street car because your a weird ricer, not knowing anything about what you've got your hands on or wait.. Wait wait.

Actually, you might not even HAVE a supra. You don't need a turbo expert, you need to start with the friggin basics. www.howthebasicsofcarsworkbeforeIrunatwinT66setup.com
check it
 

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only read the first few replies, but I think he meant something slightly different with the different sized turbos.

I think he was suggesting say a 59mm turbo and a larger turbo such as a 68mm turbo. But, not run them at the same time but switch between the two for street vs drag. Both the turbos would be on a common manifold, and there would be some kind of valve at each turbo flange to block flow. Valves could be either pressure driven valves similar to the OEM sequential valves (controlled by a vsv), or electronicly controlled and operated, similar to an exhaust cutout.

The exhaust flow to the selected turbine wouldnt be as efficient as a traditional single setup, but It seems do-able. the challenge lies with fitting all thaty shit in there.
 
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