.81 housing to .96 housing swapped again, feels GOOOOOD!
11-24-2007, 12:38 AM
#1
.81 housing to .96 housing swapped again, feels GOOOOOD! Didn't make any measurements on back pressure, but I did try to dyno it. My results are completely subjective at this point but I figured I'd share them anyways. At 14psi of boost it's making 15hp more than it use to make on 16psi. I'm also making power clear out to 6500 rpms now and the graph was still climbing. It use to peak at 5700 rpms previously. I had tried using this housing before with very poor results and I was unable to spool it well. Those issues were caused by a bad exhaust setup after the turbo causing too much after turbo back pressure and not having my exhaust insulated as it is now. The car spools so good on the .96 housing it makes me wish I had a 1.08 to try out.
On the highway the car pulls much much harder up top, instead of making the 2-3 shift at 105mph i'm able to make it at 120mph now, pulls like a freight train and doesn't feel like it's letting up like it did on the .81 housing. With the .81 housing it felt like it was out of breath and nosing over at 6200. I think a lot of the gain now is also because my converter pretty loose for the power, it doesn't really get agains't the converter until 6100ish which is where I was shifting it previously.
If all goes well I'll be at the track on friday to see what kind of difference it makes. Previous best MPH was 134.55 mph @ 20psi of boost. That calculates out to an average of 725 rwhp @ 3850lbs so I'd say I was pushing close to 800 rwhp peak which is probably quite a bit for a .81 a/r housing.
For those wondering about spool difference, I can't tell any difference what so ever so I'm guessing I had a ton of back pressure previously. There was ZERO difference noticable in spool between the .81 and the .96, it will still build 20psi on the transbrake in about 3 seconds just like it did on the .81 ( I launch on 5-9psi depending on track conditions).
My fueling leaned out as well, it went from 10.8-11.0 a/f to 11.8 a/f at the same boost level with just the housing swap.
I'll have more objective results after getting some track passes, dyno wasn't of much use since we couldn't get the car to not break the tires loose over 15psi.
On the highway the car pulls much much harder up top, instead of making the 2-3 shift at 105mph i'm able to make it at 120mph now, pulls like a freight train and doesn't feel like it's letting up like it did on the .81 housing. With the .81 housing it felt like it was out of breath and nosing over at 6200. I think a lot of the gain now is also because my converter pretty loose for the power, it doesn't really get agains't the converter until 6100ish which is where I was shifting it previously.
If all goes well I'll be at the track on friday to see what kind of difference it makes. Previous best MPH was 134.55 mph @ 20psi of boost. That calculates out to an average of 725 rwhp @ 3850lbs so I'd say I was pushing close to 800 rwhp peak which is probably quite a bit for a .81 a/r housing.
For those wondering about spool difference, I can't tell any difference what so ever so I'm guessing I had a ton of back pressure previously. There was ZERO difference noticable in spool between the .81 and the .96, it will still build 20psi on the transbrake in about 3 seconds just like it did on the .81 ( I launch on 5-9psi depending on track conditions).
My fueling leaned out as well, it went from 10.8-11.0 a/f to 11.8 a/f at the same boost level with just the housing swap.
I'll have more objective results after getting some track passes, dyno wasn't of much use since we couldn't get the car to not break the tires loose over 15psi.
Last edited by Zombie; 11-24-2007 at 12:52 AM.
