FI 76mm 6.53@108 QCSB 06 - Suspension Setup
- Thread starter ChrisG88
- Start date
ChrisG88
New member
1/2 turn preload level ground with me in drivers seat
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DIESEL_POWER
NGM Diesel
Your issue is not the turbo, you need a Wastegate. Try a 45 or 50mm gate.
ChrisG88
New member
I agree a gate would have helped it live. By going to a 96 turbine with the FI 76 I have not had drive pressure or turbo issues. And the truck is faster than before. The setup is only temporary until the new engine is done.
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Smokem
Turbler
Don't rule out the cast wheel S476, it's a good option and uses the actual Borg turbine not a re-profiled 92mm wheel.
Big Blue24
Comp Diesel Sponsor
First off, thanks for sharing your experiences and track times and boost/drive numbers, great feedback for everyone!!!
Secondly, Did the big turbine 476sxe have the new larger AR SXE compressor cover, easy to spot with the dual option v-band/hose discharge and the cast-in speed sensor port?
When you option the 476sxe with the 87mm turbine, it comes standard with the old John Deere/Race cover that came standard on the Borg S480 SX series. When you option the 476sxe with the big 96mm turbine wheel, it comes with the new larger AR, improved map groove angle SXE cover. The cover made the old S480 go from 120 lbs to min to 130 lbs. In order to see the max flow/benefit of the 476sxe, you definitely want the new compressor cover.
It's cool to see aftermarket turbo companies beating the manufacturers, especially when it's a newer trending/hot model like the SXE.
Secondly, Did the big turbine 476sxe have the new larger AR SXE compressor cover, easy to spot with the dual option v-band/hose discharge and the cast-in speed sensor port?
When you option the 476sxe with the 87mm turbine, it comes standard with the old John Deere/Race cover that came standard on the Borg S480 SX series. When you option the 476sxe with the big 96mm turbine wheel, it comes with the new larger AR, improved map groove angle SXE cover. The cover made the old S480 go from 120 lbs to min to 130 lbs. In order to see the max flow/benefit of the 476sxe, you definitely want the new compressor cover.
It's cool to see aftermarket turbo companies beating the manufacturers, especially when it's a newer trending/hot model like the SXE.
ChrisG88
New member
Yes sir no problem. I enjoy sharing my experiences to help others make decisions and take the best route possible when choosing a new turbo. Yes the 76/96 SXE had the new V2 cover. I ended up sending the cover to Jose at Forced for him to use on my new 80/96 ETR that I will be running as a single.
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Big Blue24
Comp Diesel Sponsor
Now I'm very intrigued, did the FI 76 turbo have the old style cover? Can you see any obvious map groove work/improvements?
Thanks Again.
ChrisG88
New member
The FI 76 was a standard Vband cover. I didn't even look for any map groove work. Threw it on, went 6.5s@108-9, and decided I wanted to try to go faster. I'm not sure the 80 will be any faster but there is only 1 way to find out!
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1stgensleeper
New member
What stall converter are you running?
ChrisG88
New member
Cummins12Club
Happy Dinosaur
I'm curious to see if you pick up any ET going to the 80 wheel.
ChrisG88
New member
Same. I have my doubts but am very curious. As soon as the cage is done I'll be at the track
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Smokem
Turbler
The larger AR cover will not change the fact the compressor wheel surpasses the supersonic threshold before a 5:1 rise in pressure, which is why they are failing as all OEM's use the same maximum wheel speed limit. In a diesel application and a sub 110mm exducer most would see better power with either of the smaller 0.63AR or 0.66AR compressor covers.
These models were clearly designed/marketed toward the gasoline drag racing market, easy to see just by looking at the sizes ie; 72mm(SFWD), 76mm(Ultimate Street), and 88mm(X275). It's unfortunate to see a good product from a good company getting a bad reputation because they are being used in the wrong application.
97rada
New member
ChrisG88
New member
From what I've experienced and seen mostly bearing issues.
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Smokem
Turbler
Specifically, over speed conditions create a harmonic resonance that results in oil separation on the bearing surfaces, mainly the thrust bearing/collar. This is why there is an industry standard regarding maximum wheel speed.
The S400 SX-E line was not designed for high pressure ratio applications, which is in all reality the best way to describe a diesel engine.
SPEEDSHIFT
New member
What boost/drive pressure level are they designed for?
Smokem
Turbler
At 1500ft elevation with 76° F intake temperature assuming a 1psig loss due to intake restriction, 50psig would equal ~ a 4.9:1 rise in pressure which is just beyond what appears to be the max rated speed for that compressor.
It's not uncommon to see compressors operate beyond the super sonic threshold in performance applications, in my opinion the failures are related to the lack of a secondary leading edge surface below the MAP groove under choke flow conditions.