Turbo's for the street

[ka67_72]

I have a single 97mm turbo on a 350 in a jaguar. My 53mm single turbo 302 ranger is more fun. Kids are putting these monsters on Hondas and saying they can spool. I wanted to see what too big off a turbo was like so I did it. I haven't got the car where I can really lay into it yet but I don't think it's going to do anything. Looks huge, makes noise and thats about it. I've got it to make a few pounds of boost but it's time to shift by then. I'm going to find something smaller. The TT454 headers are almost done with 105 hours into them. I'll gladly build a set for anyone who wants them. I don't know what kind of power they'll make but they sure draw a crowd.

http://hotrodders.com/gallery/showga...00&ppuser=7803

Thanks,
Kevin

[rocketman]

I think I have him talked into a 454 sbc TT set-up using a pair of 70mm.I have to research cylinder heads some more,but I think 18* degree's will work fine.

Any thoughts or opinions,I'm open to suggestions.

[nitrorocket]

I am not so sure a 454 sbc combo would be so stout with a turbo setup. The Super long stroke added with the crazy torque a turbo makes will make havok on your rod bearings. Just a thought.

Also, take my tiny little $5000 basic 347" LS1 for example. It makes 1000 hp on 93 octane pump, will he need a 454??

[clill]

rocketman....I have a twin turbo smallblock, a 10-71 blown intercooled big block, have had other turbo and blown cars and if I were starting with a clean sheet for a customer I would go with a twin turbo LS engine. They are great engines that hold up to lots of hp and don't leak oil etc. The LS engines are where all hipo development is headed. Talk your customer into it and find a way to make it look killer. He will love driving it and he won't be bugging you because it breaks or leaks oil. Two cents from a guy that has been there-done that again and again and again.

[camcojb]

Originally Posted by clill

rocketman....I have a twin turbo smallblock, a 10-71 blown intercooled big block, have had other turbo and blown cars and if I were starting with a clean sheet for a customer I would go with a twin turbo LS engine. They are great engines that hold up to lots of hp and don't leak oil etc. The LS engines are where all hipo development is headed. Talk your customer into it and find a way to make it look killer. He will love driving it and he won't be bugging you because it breaks or leaks oil. Two cents from a guy that has been there-done that again and again and again.

Amen brother.

[rocketman]

Originally Posted by clill

rocketman....I have a twin turbo smallblock, a 10-71 blown intercooled big block, have had other turbo and blown cars and if I were starting with a clean sheet for a customer I would go with a twin turbo LS engine. They are great engines that hold up to lots of hp and don't leak oil etc. The LS engines are where all hipo development is headed. Talk your customer into it and find a way to make it look killer. He will love driving it and he won't be bugging you because it breaks or leaks oil. Two cents from a guy that has been there-done that again and again and again.

Thanks for the idea,to be honest I didn't think about LSX stuff.

[J2SpeedandCustom]

Ok so let's take that 500+ CID motor and the 1000hp goal.
Can I use twin 67mm's? I've heard they can make 1000hp?"

Nope! There's nothing wrong with twin 67mm's they will definitely make 900hp, just not in this scenario. Here's why: 900hp represents a fairly constant amount of air/fuel mixture, regardless of whether it's being made by a small motor at high boost (eg. 380ci at 20psi) or a large motor at low boost (eg. 500ci at 10psi).

The first problem is that most turbo compressors are only able to reach their maximum airflow when they are running at high boost levels. For example, a GT42 is able to flow about 94lbs/min of air at 32psi of boost, but it can only flow around 64lbs/min of air at 10psi. Often people are quick to assume that high boost means high heat and therefore decreased efficiency, but in reality, it takes higher boost levels to put most turbos into their "sweet spot". In this particular example, the turbo is capable of almost 50% more HP at high boost levels than it is at low boost levels.

The other problem is related to backpressure. If the exhaust system (headers, turbine, downpipe, etc.) is the same between both motors, the backpressure will be roughly the same. Let's say the backpressure measures at 48psi between the motor and turbo's exhaust turbine. The big motor will run into a bottleneck because there is 48psi in the exhaust and only 10psi in the intake (a 4.8:1 ratio). This keeps the cylinder from scavenging/filling fully and therefore limits power. The small motor, on the other hand, has 20psi of boost (only a 2.4:1 ratio) to push against the backpressure. Therefore it is able to be much more efficient under these conditions.

The bottom line is, as your motor size increases, your boost level will go down (in order to achieve the same power level). In such a case you will need to maximize the flow potential of your compressor and minimize the restriction of your exhaust system (including the turbine) in order to reach your power goals.

So in summary you need to have a turbo compressor that is efficent at a lower boost like 10psi. In a perfect world on a 500cid a big single like a 101mm would be ideal.

[rocketman]

Originally Posted by J2SpeedandCustom

Ok so let's take that 500+ CID motor and the 1000hp goal.
Can I use twin 67mm's? I've heard they can make 1000hp?"

Nope! There's nothing wrong with twin 67mm's they will definitely make 900hp, just not in this scenario. Here's why: 900hp represents a fairly constant amount of air/fuel mixture, regardless of whether it's being made by a small motor at high boost (eg. 380ci at 20psi) or a large motor at low boost (eg. 500ci at 10psi).

The first problem is that most turbo compressors are only able to reach their maximum airflow when they are running at high boost levels. For example, a GT42 is able to flow about 94lbs/min of air at 32psi of boost, but it can only flow around 64lbs/min of air at 10psi. Often people are quick to assume that high boost means high heat and therefore decreased efficiency, but in reality, it takes higher boost levels to put most turbos into their "sweet spot". In this particular example, the turbo is capable of almost 50% more HP at high boost levels than it is at low boost levels.

The other problem is related to backpressure. If the exhaust system (headers, turbine, downpipe, etc.) is the same between both motors, the backpressure will be roughly the same. Let's say the backpressure measures at 48psi between the motor and turbo's exhaust turbine. The big motor will run into a bottleneck because there is 48psi in the exhaust and only 10psi in the intake (a 4.8:1 ratio). This keeps the cylinder from scavenging/filling fully and therefore limits power. The small motor, on the other hand, has 20psi of boost (only a 2.4:1 ratio) to push against the backpressure. Therefore it is able to be much more efficient under these conditions.

The bottom line is, as your motor size increases, your boost level will go down (in order to achieve the same power level). In such a case you will need to maximize the flow potential of your compressor and minimize the restriction of your exhaust system (including the turbine) in order to reach your power goals.

So in summary you need to have a turbo compressor that is efficent at a lower boost like 10psi. In a perfect world on a 500cid a big single like a 101mm would be ideal.

Thanks,

So in a nutshell if you are going to use big cube's might as well make big hp,rather than choke it down.i have been playing with some #'s and a single big turbo on a large cube motor could easily make 2k hp.

[nitrorocket]

No, what he is saying is that you will only need lets say 5 lbs of boost to make 1000 hp on a 540 versus about 18-20 lbs on a 350.

Real basic...Hp requires air/fuel. A turbo is rated by the amount of air it flows. A pair of tine 60-1 hi-fi's will make 1100 hp on a 347" at 21 psi, and 1100 on a 454" at 17 psi. So regardless of boost, they are only capabale of flowing a certain amount of air regardless of motor size. Just need to make sure they have properly matched Exhaust housing to keep the turbine speed in the sweet spot.

To me is does not make sense to do a high dollar big inch motor to only make 1000 hp.

An ls1 is the best engine ever made. Look at my factory headed tiny 347"!!

[rocketman]

Originally Posted by nitrorocket

No, what he is saying is that you will only need lets say 5 lbs of boost to make 1000 hp on a 540 versus about 18-20 lbs on a 350.

Real basic...Hp requires air/fuel. A turbo is rated by the amount of air it flows. A pair of tine 60-1 hi-fi's will make 1100 hp on a 347" at 21 psi, and 1100 on a 454" at 17 psi. So regardless of boost, they are only capabale of flowing a certain amount of air regardless of motor size. Just need to make sure they have properly matched Exhaust housing to keep the turbine speed in the sweet spot.

To me is does not make sense to do a high dollar big inch motor to only make 1000 hp.

An ls1 is the best engine ever made. Look at my factory headed tiny 347"!!

Well after I sat and reread it I follow that,4 hrs sleep this morning,is making it alittle hard function,anyway this project is spiraling out control at a fast rate.I just had lunch with guy and he's coming up with this monster turbo idea,I told him I can build it,I need a plan and stick too it.