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About time to upgrade from stock turbo


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I think I have finally reached the point that I want to upgrade from the stock turbo. I am putting down around 220hp with the stock turbo, saab intercooler and stock log type exhaust manifold. I have an NPR intercooler (small one). I want to put the typical 57 trim TO4E hybrid turbo in and put the NPR IC in at the same time. Also, I want to build a new exhaust header from the Weld Els when I install the new turbo. With the three changes at once what would you guys expect me to pick up in power at about the same boost level of 14psi? And remember I am at high altitude so 14psi is more like 11psi at sea level. I am hoping to pick up about 100hp? I want to build the new header because I would like the benifits of better spool and flow. The stock log type seems pretty small. Get your guess in now and we'll see what the outcome is. :)

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I wouldn't clip. It just hurts spool. The exducer is still small so you don't gain anything. Garrett did tests and has an article on clipping.

 

A standard wheel is too much of a mismatch as far as flow. If you are trying to keep the stock Z turbine housing it can be machined to fit any wheel, as far as I know up to a P trim. I like O trims. The inducer has a large diameter for good torque to turn the shaft and the exducer is about the same as a stg 3. I run that wheel my L28 and ran one on the 7M with a T58 before going with a T66/ P trim. Has great spool and makes good power. Most people try going bigger on the compressor and not the turbine side. That's why there are so few L28's that make over 400 rwhp.

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This may sound funny, but I am trying to get as much gain as I can while retaining about the same spool rpm as the stock setup. For my goals with the car I like having full boost by 2800rpm in 3rd gear. So I don't mind sacrificing hp by staying at the lower rpms and would rather stay with a turbo that spools early and runs out of breath early than have spool at 35-3800 rpms. I will be more than happy if I can retain the early boost and reach about 320hp at the wheels.

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I would skip the E and get a 60-1 or something with a newer GT 61mm wheel and atleast a stage 3 turbine min. 14-16 psi should get you 350 rwhp on a stock manifold. I made 358 or 368 rwhp at 15psi. Don't know how much that would be at your altitude.

 

Nice advice. I really like the 61mm or GT56trim with a stage V turbine wheel. The 61mm might surge with t04E cover without anti surge port though.

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Moby, you may want to consult JeffP's Extreme 280ZXT Webpage on Anglefire for his older turbine specifications. I know when rolling in second gear at 3000rpms, when he nailed it 23# was instantaneous. He was getting boost around 2500 if I recall.

 

http://www.angelfire.com/extreme/280zxt/

 

And it incorporated a cut stock turbine housing, with some other center section and compressor section. I believe he actually has one or two of those housing still laying around his garage still. He held on to the stock manifold (with some hand porting to the inlets and turbo flange area) to 450HP. His last tests indicated 23psi exhaust manifold backpressure at the turbine inlet, to 23psi intake manifold plenum pressure at 7000rpms in second gear.

Testing those numbers in anythign but second would be suicide! LOL

 

He had a really boosty-responsive setup and used that log manifold to 450HP...

 

Now you want to make some real power, snag one of those Euro Manifolds! They have internal passages bigger than the 1 5/8" Tube Headers SoFla Performance was making! The only restriction on that unit seemed to be head port exit, and that was easily portable to help with the flow! But I digress...

 

Good Luck!

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Guest bastaad525

Moby - this is a useless reply but I just wanted to say I like and agree with your goal... whenever I do think about upgrading the turbo on mine that same thought occurs to me... I do NOT want a turbo that spools up much later in the RPM band or ANY later really... this is why I've often just thought of ways I could upgrade the stock turbo for better flow and efficiency and not lose that punch at 2800rpm.

 

 

I've often considered also just going with a ball bearing turbo that is maybe a little better than the stock turbo in other ways... since the ball bearign would spool faster, could go with a slightly larger turbo but hopefully still keep the same curve.

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Well, I just went ahead and bought the clipped turbine turbo. If I don't like it at all I will sell it or get another like it for a V8. I'll keep you guys informed when i get it installed. At my pace that will probably be 3 months. I am still going to build a weld el header when I put it in, because I want practice at doing that.

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