7875 worth it?
Thread Starter
Racer
Joined: Jun 2017
Posts: 365
Likes: 18
7875 worth it?
Hi all my aim is to get to between 700-800rwhp on my ls2 with tick stage 1, 60lb injectors, bap.
Currently have a bw369sxe that dies off around 5250rpm and being held back by a 2.5” downpipe and exhaust.
Question is I’m having a shop build a new downpipe/exhaust, hoping for 3.5” but downpipe might have to be 3” into 3.5” due to space.
While im there should I try a vs racing billet 7875 ar 1.25? Is it likely to be a better match then my current bw?
i know ideally I’d get a bigger unit but I have no space left at all and want a quick spooling unit for street and circuit racing.
Also would a mcleod rst be sufficient or should I go with the rxt?
thanks in advance.
Currently have a bw369sxe that dies off around 5250rpm and being held back by a 2.5” downpipe and exhaust.
Question is I’m having a shop build a new downpipe/exhaust, hoping for 3.5” but downpipe might have to be 3” into 3.5” due to space.
While im there should I try a vs racing billet 7875 ar 1.25? Is it likely to be a better match then my current bw?
i know ideally I’d get a bigger unit but I have no space left at all and want a quick spooling unit for street and circuit racing.
Also would a mcleod rst be sufficient or should I go with the rxt?
thanks in advance.
Drifting
Joined: Feb 2006
Posts: 1,585
Likes: 15
From: New Hartford IA
That new 7875 is nice with the 1.25 housing. It will be a good upgrade over the 369sxe and hit your goal as long as you manage all restrictions like you say. All the turbos in this frame are limited by the turbine so anything to address that area is a plus. I'd also get the RXT at that point as it still drives decent.
Last edited by slow ride; Aug 8, 2019 at 11:07 AM.
Thread Starter
Racer
Joined: Jun 2017
Posts: 365
Likes: 18
That new 7875 is nice with the 1.25 housing. It will be a good upgrade over the 369sxe and hit your goal as long as you manage all restrictions like you say. All the turbos in this frame are limited by the turbine so anything to address that area is a plus. I'd also get the RXT at that point as it still drives decent.
Drifting
Joined: Feb 2006
Posts: 1,585
Likes: 15
From: New Hartford IA
My RXT held close to 1000whp, but slipped a bit as peak torque got into the higher 900's It will be perfect in the 700-800 range. I really wanted the sxe369's to work out better, but they all seem to show poor results on v8 gas stuff. Even the base 7875 would be a big improvement over the sxe369 IMHO
Melting Slicks
Joined: Mar 2006
Posts: 2,754
Likes: 380
From: South Florida FL
before doing all that and spending 1000-2k?, i'm assuming you have a top mount setup. I'll remove the hood, and fab up a quick short 3.5" hood exit for science, just to verify you have an exhaust restriction, and not a turbo limitation. it's $100 is material. One reason I switched from single to twins. it to be able to run more exhaust. it's hard to package a large single exhaust to make big power, and maneuver it pass the chassis
Thread Starter
Racer
Joined: Jun 2017
Posts: 365
Likes: 18
Thanks but I ended up buying the 7875 anyway as got a good price.
The way I see it is if it is the exhaust I had to sort it anyway and if it is the turbo well I have a different one now anyway.
Hopefully will get money for the Borg anyway so the 7875 will end up costing a few hundred
The way I see it is if it is the exhaust I had to sort it anyway and if it is the turbo well I have a different one now anyway.
Hopefully will get money for the Borg anyway so the 7875 will end up costing a few hundred
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Melting Slicks
Joined: Apr 2018
Posts: 3,185
Likes: 779
Do you have the organic disk? I do and my doesn’t chatter at all, feels damn near stock and is holding 900....so far at least, it’s got about 2500 miles on it
Last edited by 73DBG; Aug 17, 2019 at 10:06 AM.
Instructor
Joined: Nov 2018
Posts: 152
Likes: 40
What kind of fuel are you running? And I don't imagine it's possible to hit those numbers on a BAP and 60lbs. I think with a 7875 you'll be above 15psi to hit 800whp, especially on ls2 heads.
With that said I think the new 7875 will work fantastically.
If I'm wrong here I'd love to know. I'm trying to plan a turbo setup for my c6 too. If BAP and 60lbers can hit mid 700's on 15+ psi... That would be huge. But I just imagine the boost levels needed will really push against the injectors and require more pump.
With that said I think the new 7875 will work fantastically.
If I'm wrong here I'd love to know. I'm trying to plan a turbo setup for my c6 too. If BAP and 60lbers can hit mid 700's on 15+ psi... That would be huge. But I just imagine the boost levels needed will really push against the injectors and require more pump.
Instructor
Joined: Nov 2018
Posts: 152
Likes: 40
I would probably opt for 100% meth if possible. You can buy a gallon of 100% meth on amazon for like 23$ shipped. And that will help extend the range of your fuel system. If you spray a lot of meth you can probably hit your goals I believe.
I think if you run 50/50 you're going to be introducing a lot of water which can be hard to tune for and at a point is a detriment to power. Water cools in the combustion chamber mainly, so it's great for detonation suppression but since WWII I've yet to see anyone really push a water injected engine to it's max potential.
The reason I bring that up, is that you'll want extra fuel on top of your port injection. So if you're running 50/50 the total volume needed will be high to get enough extra fuel (meth) added to the chamber.
Long winded but hopefully I explained my reasoning why I would do pure meth in your case. I'm not at all against 50/50 normally though.
Last edited by 4head; Aug 22, 2019 at 08:20 PM.