Turbo AR Effect on Drive Pressure
#21
#23
Hey , ramble on!! Curious if you've made a pass on pump gas ? I'm running a 6L / cast 7875 myself but limited to pump gas and W/M , at about the 600rwhp level now and afraid to push it further. Not that I could use any more on the street , just to make a hero pass LOL. Will be interested in your results , cheers
#24
@rel3rd how high do you spin yours?
Hey , ramble on!! Curious if you've made a pass on pump gas ? I'm running a 6L / cast 7875 myself but limited to pump gas and W/M , at about the 600rwhp level now and afraid to push it further. Not that I could use any more on the street , just to make a hero pass LOL. Will be interested in your results , cheers
#25
[QUOTE
No, never have made a pass at all on 93. Have beat up on it pretty good, on the street, with mostly 93 unleaded,[/QUOTE]
What is the highest Boost setting and Timing on 93
No, never have made a pass at all on 93. Have beat up on it pretty good, on the street, with mostly 93 unleaded,[/QUOTE]
What is the highest Boost setting and Timing on 93
Last edited by FrankieD; 04-19-2021 at 11:47 PM.
#26
Way too many variables, and every setup is different.
IMO, a lot depends on how confident you are in your tune, and the functionality of all the mechanical parts that make that tune work, to keep it "safe"...
The highest I have personally felt OK with, is 14psi and 14 degrees, but like I said, that's just goofing off on the street, so no long extended 3 gear pulls, like at a dragstrip. I'm at 18-19 degrees with 4-5psi. Zero KR. I'm sure some have ventured higher
IMO, a lot depends on how confident you are in your tune, and the functionality of all the mechanical parts that make that tune work, to keep it "safe"...
The highest I have personally felt OK with, is 14psi and 14 degrees, but like I said, that's just goofing off on the street, so no long extended 3 gear pulls, like at a dragstrip. I'm at 18-19 degrees with 4-5psi. Zero KR. I'm sure some have ventured higher
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The BallSS (04-21-2021)
#29
I would say it is. I’m pretty sure I’m at 15 degree at 15 psi on 93. 19 seems pretty high. I have 9.4:1 compression btw. Maybe if he’s 8.5:1 that wouldn’t be too aggressive. I dunno.
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The BallSS (04-21-2021)
#30
Timing mark on plugs was not near bend at all so felt like its a conservative number.
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The BallSS (04-21-2021)
#31
Totally understandable with that inferior LTX combustion chamber design, totally kidding lol. ; )
There's a gent on here with a 370ci LS, A2W running 18 lbs. on pump fuel so I'd like to make as much power as possible safely on pump, goal being 800whp.
My setup is similar, fewer cubes but similar.
I also noticed rel3rd's comment about pulling timing out at peak torque, then brought it back in the upper rpm range which seems very smart for longevity.
Sorry, didn't mean to hijack the OP's thread.
#32
Glad Im not the only one making the change from .96 to 1.25 with my t4. Most guys are auto and dont have back to back comparisons so its hard to judge the true value of the swap.In my case this is the only change and I noticed slightly better response and have dropped a pound of backpressure.Just got the turbo back from ceramic coating and should be out testing next weekend.once the track opens up again i can get mph differences from my on3 turbo vs the vsr with 1.25 housing.
#33
I got my housing in Thursday. I didn’t realize it was divided. I don’t have pipes merged at the flange, I have one big pipe going into my turbo. This divided housing has small holes compared to the gasket, I felt like while the housing would flow better, it would be a bottleneck here. I decided to open it up instead of having a huge flat surface in the middle of exhaust flow.
before:
after:
before:
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rel3rd (04-25-2021), The BallSS (04-26-2021)
#35
I got my housing in Thursday. I didn’t realize it was divided. I don’t have pipes merged at the flange, I have one big pipe going into my turbo. This divided housing has small holes compared to the gasket, I felt like while the housing would flow better, it would be a bottleneck here. I decided to open it up instead of having a huge flat surface in the middle of exhaust flow.
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rel3rd (04-25-2021)
#37
what I did was ordered a 4” and a 3.5” v band set. I’m going to put a 3.5” v band flange in my lathe and machine it to fit inside the 4” flange. And weld it together like that. There won’t be any restriction because the 3.5” pipe is a little larger than the exit hole.
I forgot to mention, my downpipe is already 3.5”, I’ll cut the 3” section off that’s at the turbo and make it 3.5”. I had planned on building another complete exhaust out of 3.5”
Last edited by Kfxguy; 04-25-2021 at 11:31 AM.
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rel3rd (04-25-2021)
#38
Although it "may" (or may not) skew my .96 versus 1.25 test, I'm going to blend the transition on mine as well.
I'm looking at one of these (pic attached) V Band adapters. That way there is no "permanent" modification having to be made to the pipes, just to make the housing work. My long term plan is to fab up a true 4" fender/nose exit downpipe, that is also equipped with a cutout. That way my quiet exhaust is still in place and used for cruising around. (See my awesome drawing attached, lol)
Short term plan is use the 4" to 3" adapter and roll with it for the foreseeable future.
.
I'm looking at one of these (pic attached) V Band adapters. That way there is no "permanent" modification having to be made to the pipes, just to make the housing work. My long term plan is to fab up a true 4" fender/nose exit downpipe, that is also equipped with a cutout. That way my quiet exhaust is still in place and used for cruising around. (See my awesome drawing attached, lol)
Short term plan is use the 4" to 3" adapter and roll with it for the foreseeable future.
.
#39
I got my housing in Thursday. I didn’t realize it was divided. I don’t have pipes merged at the flange, I have one big pipe going into my turbo. This divided housing has small holes compared to the gasket, I felt like while the housing would flow better, it would be a bottleneck here. I decided to open it up instead of having a huge flat surface in the middle of exhaust flow.
before:
after:
before:
after:
#40
In all honesty i would just get the monkey fab reducer, its a very nice piece and smooth transition.Just need to cut your exhaust and weld the 3inch onto it.Much cleaner look and 0 flow restrictions.
So i just did some street pull and logs with my new housing. The car definitely shows improvement over 5500rpm for me. Boost carries throughout and no tapering. Backpressure has dropped 2 points.Spool up seems maybe 3-500rpms later but that could be fixed with boost controller settings. It feels like this has crested me over 800whp on pump 93,a gain of 30-40whp and more in torque it comes up very strong. I can see why alot of guys suggest a t6 to start. I started to hit boost cut which never happens on my old turbo on high boost.
So i just did some street pull and logs with my new housing. The car definitely shows improvement over 5500rpm for me. Boost carries throughout and no tapering. Backpressure has dropped 2 points.Spool up seems maybe 3-500rpms later but that could be fixed with boost controller settings. It feels like this has crested me over 800whp on pump 93,a gain of 30-40whp and more in torque it comes up very strong. I can see why alot of guys suggest a t6 to start. I started to hit boost cut which never happens on my old turbo on high boost.