On3 7875 spool?
On3 7875 spool? Anybody ever back to back tested a Chinese 78/75 vs a pt7675 or BW s475? I know power output will be higher but I'm interested in spool characteristics. I swapped from an lq4 to a L33 this year and now my s10 won't 60' to save it's life. I could build 9-10psi on the 2step with antilag with the 6.0 and now I'm lucky to get 4-5psi with the 5.3L.
TECH Junkie
Joined: Jul 2015
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Anybody ever back to back tested a Chinese 78/75 vs a pt7675 or BW s475? I know power output will be higher but I'm interested in spool characteristics. I swapped from an lq4 to a L33 this year and now my s10 won't 60' to save it's life. I could build 9-10psi on the 2step with antilag with the 6.0 and now I'm lucky to get 4-5psi with the 5.3L.
Timing is around 25* until I start seeing boost and then it pulls to 17.5* at full boost. Afr is 12.5 until it hits 5psi and then it drops to 11.5. The problem is I have a rear mount and a tight converter. The converter is perfect on top end at 21psi but I can only get to 3,100 on the foot brake. With the 6.0 I could build 5-6psi at 3,100 on the 2step and then hit the antilag and jump to 10psi real quick. With 5.3 it only builds 2-3psi and flat lines. If I hit the antilag it looses too much torque and drops off the 2step.
So the s475 was worse? Forced inductions is telling me that it should be better. Was the s475 a t4 with 83mm hot side?
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That's odd... my S480 would build boost a lot earlier then that on a 325. How much power/boost are you making with the 7875?
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Verdad Gallardo I used to have a 7675 and it came online real fast on a 5.3L. When you say you start pulling timing when you see boost, at what boost level? I usually leave timing in until it gets 5-7lbs going then start pulling it out slowly. Same like you said with A/F basically but I would pull that out slower as well. I don't dip into the 11's until over 10lbs. Assume your on E85 or something better then pump running 21lbs at 17.5 degrees?
That's not bad at all for a $400 turbo!
I used to have a 7675 and it came online real fast on a 5.3L. When you say you start pulling timing when you see boost, at what boost level? I usually leave timing in until it gets 5-7lbs going then start pulling it out slowly. Same like you said with A/F basically but I would pull that out slower as well. I don't dip into the 11's until over 10lbs. Assume your on E85 or something better then pump running 21lbs at 17.5 degrees?
I used to have a 7675 and it came online real fast on a 5.3L. When you say you start pulling timing when you see boost, at what boost level? I usually leave timing in until it gets 5-7lbs going then start pulling it out slowly. Same like you said with A/F basically but I would pull that out slower as well. I don't dip into the 11's until over 10lbs. Assume your on E85 or something better then pump running 21lbs at 17.5 degrees?
I have a pt7675 on my Silverado that doesn't get raced anymore so I might swap the turbos and see if there is a difference. I'm sure the pt will be a little more efficient per psi and probably make make a little more maxed out. I've always heard that the extra 2mm on the compressor wheel slows spool a little so it's worth a shot.
Teching In
Joined: Jul 2015
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Nice, thats making some good power. That's faster then I ran at 20lbs with the PT7675CEA with my car being about 4k lbs, I went 10.1 at about 135. Then I turned it up to about 24lbs and ran 9.80@140 before swapping it out. Seems to be very comparable except the 7875 is a killer deal.
Nice, thats making some good power. That's faster then I ran at 20lbs with the PT7675CEA with my car being about 4k lbs, I went 10.1 at about 135. Then I turned it up to about 24lbs and ran 9.80@140 before swapping it out. Seems to be very comparable except the 7875 is a killer deal.
TECH Junkie
Joined: Jul 2015
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Did the install last night, this turbo does NOT spool quite like the pt7675....but the car still runs Ok. Seat of the pants, I might be a touch down on power as well. But then again it could be all mental, as this on3 is much more quiet than the precision so who k n ows.
