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got some low boost hits in yesterday. Had the car pretty well tuned i thought on the street, just didnt have an idea where timing should be on e85. I had what i think was fairly conservative numbers in. I had pulled 3rd gear on the street at 12 psi and it felt good.
first pull on dyno as it came in on the street was 12 psi and made 1217 whp. However its spooling slow on the dyno. On street it will hit target boost by 5800-5900 ish. Dyno wasnt seeing boost til 6300-6400 on 12 psi. Later on higher boost. Not happy about that since my hp peak is likely in the 6200-6300 range. But i left the tune as it was here and moved to 15 psi
first hit on 15 made 1325. Added 2 degs and it made 1397. Added another deg and tried leaning it out made 1401. So backed that deg out and left it alone.
tried a hit on 19 psi and forgot my wideband correction turned off above 6800 and above 16 psi but it was working to that point and made 1535. I turned my correction on And leaned it out and made same power but after the peak picked up 50 whp to redline. Was gonna start playing with timing but the shifter cable bracket came undone, lost gears, and couldnt get it on the dyno so had to unstrap and leave.
Dang, Orr89RocZ, you build some big power street cars!
I'll never forget that video from a couple years ago with an 8 sec pass looking as calm and collected as my truck driving down the street. You got your crap figured out!!!
Car drives good all things considered. Its on e85 and does well. I had in on pump gas to 12 lbs earlier. E85 i just corrected fuel to same air fuel and had 2 deg more i think when it made 1217. Now added 4 more lol so it should be mid higher 1200’s there
at 1217 i hooked 3rd from a roll and ran away from two street bikes like they were standing still. So its got some speed to her. I had briefly tried 16 psi before the dyno and it was sketchy, was skating with traction but one time it seemed to stay planted.
i’m gonna swap to 1.15 ar housings and try to spool it sooner. I dont like how late it comes in esp given my power band seems to fall off after 6500 pretty hard but my boost curve is dropping at same time so who knows.
Yeah pretty sure its losing alot of heat from the mid mounts. The 3” piping is wrapped but not coated and is a type of aluminized mild steel that seems to shed heat lol. I wanna do it in 409 stainless i think or get it coated and wrapped.
I hear other guys with similar combos spooling way earlier. So im gonna try the housings first and see what happens
Strange 12 bolt so far. It probably wont like it for long at the track. 12 bolts can take abuse tho. 1200-1300 in another car it lasted awhile but did go thru a ring gear set in a season of making hits. Probably 30 passes atleast
quick pull in 3rd on roughly 1350 whp. Maybe touch less. Wasnt sure it would hook it but seemed to lol. Took my buddy for a ride. He has a lsx car thats gone 7.17 at 193 with around 1500’s whp maybe closer to 1550-1600. He was abit scared of how hard this car hit lol but on the street things feel soo different
quick pull in 3rd on roughly 1350 whp. Maybe touch less. Wasnt sure it would hook it but seemed to lol. Took my buddy for a ride. He has a lsx car thats gone 7.17 at 193 with around 1500’s whp maybe closer to 1550-1600. He was abit scared of how hard this car hit lol but on the street things feel soo different
got some low boost hits in yesterday. Had the car pretty well tuned i thought on the street, just didnt have an idea where timing should be on e85. I had what i think was fairly conservative numbers in. I had pulled 3rd gear on the street at 12 psi and it felt good.
first pull on dyno as it came in on the street was 12 psi and made 1217 whp. However its spooling slow on the dyno. On street it will hit target boost by 5800-5900 ish. Dyno wasnt seeing boost til 6300-6400 on 12 psi. Later on higher boost. Not happy about that since my hp peak is likely in the 6200-6300 range. But i left the tune as it was here and moved to 15 psi
first hit on 15 made 1325. Added 2 degs and it made 1397. Added another deg and tried leaning it out made 1401. So backed that deg out and left it alone.
tried a hit on 19 psi and forgot my wideband correction turned off above 6800 and above 16 psi but it was working to that point and made 1535. I turned my correction on And leaned it out and made same power but after the peak picked up 50 whp to redline. Was gonna start playing with timing but the shifter cable bracket came undone, lost gears, and couldnt get it on the dyno so had to unstrap and leave.
i’ll go back and try for 30 psi some day
What is your AFR? I'm thinking between 11.5.11.7 would be good at WOT for max HP efforts. My C7 is right at 12 but that is where the LT4 likes to be for most hp. My TT 347cid was set with the boost controller at 18# on 100 octane and made 850 whp 11.7 AFR. The BB with boost really get crazy. lol.
Boosted applications are usually happy around 11.2
GD
All my LS blown applications have been no richer than 11.5. On my TT setup I setup dual wide bands, the driver side was 11.5 and the passenger side was 11.7. When I was getting my C7 tuned last month after I installed the 2650 the tuner who is arguably the best in Ca told me the LT4s like right around 12, they don't run better being richer like the LS cars with the PD blowers. I noticed you are in a neighboring State and do tuning. I can't find anybody around in Ca that tunes these cars, If I end up doing more with my Thirdgen I was going to hit you up to see if I could trailer my car up to you in Portland for a dyno tune? I haven't been to Oregon in 30 years or so it would be nice to take a drive, plus I have relatives in Washington I haven't been up to visit so it might be just part of long road trip.
Im mid high 11’s at lower boost. Gas scale on e85. Seemed to make best around 11.4 on 15 psi. I’ll likely stay around 11.2 much above that but we shall see if i ever get it back to the dyno. Waiting for cooler air
All my LS blown applications have been no richer than 11.5. On my TT setup I setup dual wide bands, the driver side was 11.5 and the passenger side was 11.7. When I was getting my C7 tuned last month after I installed the 2650 the tuner who is arguably the best in Ca told me the LT4s like right around 12, they don't run better being richer like the LS cars with the PD blowers. I noticed you are in a neighboring State and do tuning. I can't find anybody around in Ca that tunes these cars, If I end up doing more with my Thirdgen I was going to hit you up to see if I could trailer my car up to you in Portland for a dyno tune? I haven't been to Oregon in 30 years or so it would be nice to take a drive, plus I have relatives in Washington I haven't been up to visit so it might be just part of long road trip.
For sure. No problem tuning the Third Gen.
AFR is very dependent on boost pressure and compression ratio of course. Based on Orr running about 20 psi on an engine with compression ratio chosen for turbocharging I assumed he was probably around 11.2
Less cylinder pressure can handle leaner mixtures. And of course 100 octane will allow a bit leaner also.
Pump gas at 20 psi is generally going to like 11.2
But as with all tuning - you give the engine what it wants. They are each a little different.
GD
Last edited by GeneralDisorder; Jul 10, 2020 at 09:56 AM.
Dyno power is short pull, so i can be leaner if it makes max power there. Longer drag pull with more load on street or track i usually add some fuel. 0.3 afr or so to be extra safe lol
Dyno power is short pull, so i can be leaner if it makes max power there. Longer drag pull with more load on street or track i usually add some fuel. 0.3 afr or so to be extra safe lol
Definitely. With high HP cars we will setup extra tables to enrich further based on time at WOT to help cool down the chambers. On the Dyno, for "glory pulls" we can typically lean out and add timing to get closer to the number the customer has in his head - which is invariably higher than what he actually achieves. Spray down the IC with water and put fans on it for 10 minutes and then do another pull......
Lol this car disappointed me when it was all motor. But for some reason boost really woke it up more than expected. I mean well into the 1200’s whp on just 12 psi is nuts. It almost tripled its na power on double atmosphere. I didnt think that was supposed to happen lol
