Robert Wilson
Member
It is a little slower than my 76GTS which had the 75mm turbine but not much. It is definitely street drivable with a 274" engine.
Anyone tried the Borg Warner S484 turbo yet?
- Thread starter GNDriven
- Start date
Robert Wilson
Member
I had a mechanical gauge measuring back pressure last year that has a check valve so it held peak pressure. I saw 45 psi of BP when when 28 to 29 lb of boost. With the 76 GTS I was over 60 psi at the same boost. I have a pressure sensor on the car now to log with Xfi and hope to have more data in a couple of weeks.
Car is shifted at 6700 to 6800 rpm.
Robert Wilson
Member
To give a better answer I pulled up a couple of xfi logs.
When leaving at 3600 rpm and 7 psi boost engine would be at 27psi in 1.05 seconds. After that, I can see the boost curve flatten out as the AMS 1000 takes over and boost settles at 28 to 29. Ramp time on AMS was set to 1.1 seconds to be all in so boost followed very close,
Thanks for the info, Robert - looks like a big increase in turbine flow vs. your old 75, assuming similar compressors. Are you running a cast or billet compressor wheel, and standard or race cover?
How long does it take for you to reach your 7psi launch boost on the brake?
Chris
Robert Wilson
Member
The turbo is a cast wheel 76 with the race cover. After engaging transbrake and going WOT, it take 1.65 seconds to go from vacuum to 6.4 lbs of boost with the 2 step at 3600 rpm and boost controller set for 7 lb. launch. Once the wastegate starts to open about the 6.4 psi mark, the boost curve flattens out and it takes another .25 seconds to hit 7 lbs.
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Wow, sounds like a quick-spooling combo for the amount of power you're putting down. I assume the 9.04 time in your sig was run with this turbo? Thanks for sharing the spool-up info - I've not been able to find a lot of that detail on here, outside of you and Turbobitt. It's very helpful for those of us currently turbo shopping 
.
Chris
.Chris
Robert Wilson
Member
Wow, sounds like a quick-spooling combo for the amount of power you're putting down. I assume the 9.04 time in your sig was run with this turbo? Thanks for sharing the spool-up info - I've not been able to find a lot of that detail on here, outside of you and Turbobitt. It's very helpful for those of us currently turbo shopping
Chris
Yes 9.04 was with that turbo. I was on the fence about going with the cast 76 or the 80 billet compressor and opted for the 76 cause I was afraid of spool up. Probably would have been fine with the 80.
turbobitt
Well-Known Member
It sound like your not out of turbo yet. Any plans to turn it up some more ?
AG.
I dropped mine off at the fab shop yesterday. I had to order a new T4 flange and new wastegate output flange for the fabricators to use. It may be ready this Friday or beginning of next week.
Robert Wilson
Member
The only 4 bolt housing I have personal experience with was the T4 .96 AR that was on the 76GTS. I was told that housing was restrictive for the 75mm exhaust wheel.
I was told that if I wanted to squeeze everything out of the turbine I should go with the 1.30 Tial housing but would sacrifice some low end so I opted for the 1.16.
Robert Wilson
Member
I do plan to turn it up. Just taking it slow due to 93 octane and methanol as I am not sure the limit. I also may be out of intercooler (CAS V2) and hope to have data soon as I have added the hot side pressure and temp sensors to test.
I previously had a COMP turbo , ball bearing, water cooled, 80mm compressor wheel with 79 straight cut exhaust wheel, with a 0.96 undivided housing. The compressor housing of the comp turbo is smaller. It spooled up dang fast, but for 80mm compressor and for what I am looking for, it just didn't seem to match my combo.
I drove my G-ride a good bit the other night. I was actually impressed with how quickly this turbo come up on boost. I feel real decent about the turbo at the moment. That being said, I need to get to the track where I can get some good data logs that will allow a proper quantitative comparison of spool up and performance. It is real humid in south MS in August, and I don't like beating the car up in this poor air, so I am planning on many September track outings. For now, I just have my seat-of-pants reaction which is impressed for sure.
I drove my G-ride a good bit the other night. I was actually impressed with how quickly this turbo come up on boost. I feel real decent about the turbo at the moment. That being said, I need to get to the track where I can get some good data logs that will allow a proper quantitative comparison of spool up and performance. It is real humid in south MS in August, and I don't like beating the car up in this poor air, so I am planning on many September track outings. For now, I just have my seat-of-pants reaction which is impressed for sure.
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