Big Turbine Wheels

[TrentNell]

Undivide it? :rofl:

Spool up is far from an issue for me. When I leave the line at 4800rpm turbos seem easy to spool.

It would be interesting to test on an auto truck. But I can not see why it would not work. Here is link to a thread with spool up data using one of these. He seemed pleased.
http://www.ls1tech.com/forums/force...pool-valve-testing-pics-nerd-like-graphs.html

You guys dont think this is an issue( seperate passages in the pedistall) ? unless a custom pedistall is made I cant see this being a viable option ?

 

[JOHNBOY]

You guys dont think this is an issue( seperate passages in the pedistall) ? unless a custom pedistall is made I cant see this being a viable option ?

I dont care for the idea of an udivided spacer. Doesnt mean it will not work.

 

[bullfrogjohnson]

I have access to a GT45F, what are the thoughts on this turbo compared to a S480?

 

[JOHNBOY]

I have access to a GT45F, what are the thoughts on this turbo compared to a S480?

I can really say. If is the GT45F that Forced sells it might be worth a try. FWIW GT45F start life as a Volvo semi truck turbo.

Forced wants the same money for a GT45F as they do the SX80. I would lean toward the SX 80. But that turbo is on my own wish list.

 

[jpowel29]

If I remember right the GT45F has a 78mm comp wheel and a 87mm exh exducer. What A/Rs are currently available for a T4 flange? I had heard that there might some difficulty in getting exhaust housings with the closure of some foundrys.

 

[duramaxsandwich]

I agree with you on the A/R thing. Borg stuff seems to be about .1 losser than Garrett stuff of the same number. The S475 and GT42 are very simalar. I actually had a buddy test them the same day on dyno with his tractor engine. The S400 was a little quicker lighing and was good for about 50hp less then the GT42. Drive pressure ratios have alot to do with RPM. I can make 60 psi of boost at 3000rpm withjust over 60psi of drive but at 4000rpm my drive jumps way up. A looser housing did not fix it. Simply the flow of the turbine wheel is over come. The S400 83mm turbine flow just sligthly less then the GT42 turbine.
Now all that said everybodies drive pressures will be different. Cams, heads, and tuning can make a difference in drive pressure.

I am leaning hard toward the 87mm turbined S480 myself.

i've been reading this thread a lot and i've been trying to figure out my new engine build. i stuck with my A5k from last year but i that it is now limiting the potential of the build. my last pull we got a good log of boost vs dp and it was way out of wack, i'm going to try a bigger exhaust housing for the next hook, but from your post above once i over come the flow of my turbine wheel a bigger exhaust housing isn't going to make any more power?

 

[MarkBroviak]

i've been reading this thread a lot and i've been trying to figure out my new engine build. i stuck with my A5k from last year but i that it is now limiting the potential of the build. my last pull we got a good log of boost vs dp and it was way out of wack, i'm going to try a bigger exhaust housing for the next hook, but from your post above once i over come the flow of my turbine wheel a bigger exhaust housing isn't going to make any more power?

Right, becuase no matter how big the housing is ALL the air has to flow through the wheel itself. Housing size only affects the when and how it comes on not how much it will flow in cfm. To each his own and setup makes more of the desicion for you than anything else. Personally I am a big fan of the s400's, work great and good life expectance for the money.

 

[Stingpuller]

S-400's

I have done everything but beat on it with a hammer and I think i'm just starting to loose a exhaust wheel! It's been a good one. Jeff

 

[JOHNBOY]

I talked to Jose at Forced Inductions today. He said that the 87MM turbine wheel flows within 1lb/min of a GT45.

 

[sweetdiesel]

I think it would be cheaper if we all would started at the biggest turbo and worked are way down

 

[bullfrogjohnson]

First test pull with the 87mm wheel was very promising. A little harder to lite but the motor sounded much happier in the higher rpm's. Truck held 4200 going down the track adn spun out without falling off the charger. Truck pulled 333 and some change

 

[White Duramax]

What exhaust housing and compressor wheel are you running?

 

[bullfrogjohnson]

What exhaust housing and compressor wheel are you running?

.90 housing with a 74mm wheel

 

[TrentNell]

:coolspot:

 

[LBZ]

only when this one lets go. I put around 20 miles a month on the truck so it could last me for a little while

Jeez, I put more miles a month than that on my work boots!!:rofl:

 

[Mike]

I have been thinking about this alot. I mean alot! I dont think the 96/87 is a good choice. AFAIK the only housing you can get is an undivided 1.32A/R T6. it flows around 62lbs/min. That is GT55 territory. To big! The 74/83 flows around 42lbs/min in a 1.1A/R T4. Just a touch less then a GT42 turbine in a similar housing. I dont have flow data on the 83/87 turbine. I have been told it flows very well though.

My problem is this. My drive is high with my GT42. I have been looking hard at the S480. What I can not decide is 74/83 or 83/87. Are we better off to go with the smaller turbine and use a wastegate to control drive? This will give us easier spooling and should limit drive pressure problem and the heat involved. Or are we better off to go to the bigger turbine ungated. Live with the harder spooling but the simpler wastegateless set up. The price difference between the two setups is not much. Tough call.

I like the waste gates to point but, we loose the lbs/min part of the turbine map which does the work in moving the additional air as drive pressure decreases. lbs/min = ability to do work. At least that's my experience.

 

[Mike]

I think it would be cheaper if we all would started at the biggest turbo and worked are way down

It's funny Simon, I go into interviews saying " How about I start out as your CEO and get 10 million a year. Then I can work my way down in tenure and you take pay the longer I'm employed by your company."

But, I wish I would have started big and worked my way down too. :rofl:

 

[sweetdiesel]

I have been thinking about this alot. I mean alot! I dont think the 96/87 is a good choice. AFAIK the only housing you can get is an undivided 1.32A/R T6. it flows around 62lbs/min. That is GT55 territory. To big! The 74/83 flows around 42lbs/min in a 1.1A/R T4. Just a touch less then a GT42 turbine in a similar housing. I dont have flow data on the 83/87 turbine. I have been told it flows very well though.

My problem is this. My drive is high with my GT42. I have been looking hard at the S480. What I can not decide is 74/83 or 83/87. Are we better off to go with the smaller turbine and use a wastegate to control drive? This will give us easier spooling and should limit drive pressure problem and the heat involved. Or are we better off to go to the bigger turbine ungated. Live with the harder spooling but the simpler wastegateless set up. The price difference between the two setups is not much. Tough call.

I cant decide weather to up to the 83 either it would be cheaper and easy install

Thing is, im always upgrading the turbos and would like to just go big this time

 

[sweetdiesel]

First test pull with the 87mm wheel was very promising. A little harder to lite but the motor sounded much happier in the higher rpm's. Truck held 4200 going down the track adn spun out without falling off the charger. Truck pulled 333 and some change

Awsome Travis!

So this is a 74/87? Do you have a back pressure gauge? Ungated? Machined housing?


just read where you said 74mm How must boost you see on your truck?

 

[TrentNell]

I cant decide weather to up to the 83 either it would be cheaper and easy install

Thing is, im always upgrading the turbos and would like to just go big this time

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