GTX3076R 0.82a/r versus 0.63a/r
#1
GTX3076R 0.82a/r versus 0.63a/r
Building a 2.4L EVO 9, few specs on the build:
I am wanting to know from those experienced with this turbo (or the GT3076R), whether given the specs and displacement of my engine build, if the 0.82a/r is the better choice of the two options? I am choosing the GTX30 in the first place, over the GT35, for its faster spool-up, and understandably I stand to lose a bit of that going from 0.63 to 0.82, but how dramatic of a shift might it be, and is the 0.82 in fact more compatible and versatile for this particular build being that it's 2.4L?
- 100mm K1 series crank
- 150mm Manley turbo tuff conrods
- 9.5:1 Wiseco Asymmetrical pistons w/ upgraded pins
- GSC S2 MIVEC cams
- GSC beehive springs
- ETS vband manifold, recirc, cat-delete
- 4.0" ETS speed density intake (no MAF)
- Stock intake manifold, stock TB, EGR delete
I am wanting to know from those experienced with this turbo (or the GT3076R), whether given the specs and displacement of my engine build, if the 0.82a/r is the better choice of the two options? I am choosing the GTX30 in the first place, over the GT35, for its faster spool-up, and understandably I stand to lose a bit of that going from 0.63 to 0.82, but how dramatic of a shift might it be, and is the 0.82 in fact more compatible and versatile for this particular build being that it's 2.4L?
Last edited by doncarbone; Oct 11, 2014 at 06:44 PM.
#2
Evolved Member
Disclaimer: I do NOT have hands on experience with this turbo.
Assuming it is twin scroll housing:
The stock Evo X turbine is 56mm, your GTX30 is 60mm.
Stock twin scroll Evo X turbine A/R is .89
I would go with the larger .82 since you went with the 30 sized turbine. I don't think this is something you would regret especially with ball bearing spool up.
Assuming it is twin scroll housing:
The stock Evo X turbine is 56mm, your GTX30 is 60mm.
Stock twin scroll Evo X turbine A/R is .89
I would go with the larger .82 since you went with the 30 sized turbine. I don't think this is something you would regret especially with ball bearing spool up.
#3
Disclaimer: I do NOT have hands on experience with this turbo.
Assuming it is twin scroll housing:
The stock Evo X turbine is 56mm, your GTX30 is 60mm.
Stock twin scroll Evo X turbine A/R is .89
I would go with the larger .82 since you went with the 30 sized turbine. I don't think this is something you would regret especially with ball bearing spool up.
Assuming it is twin scroll housing:
The stock Evo X turbine is 56mm, your GTX30 is 60mm.
Stock twin scroll Evo X turbine A/R is .89
I would go with the larger .82 since you went with the 30 sized turbine. I don't think this is something you would regret especially with ball bearing spool up.
#6
Evolved Member
Grimgrak says you can get twinscroll, then you should definitely do it.
There is an interesting post on the mazda forums, with data from mazda on twin scroll versus single (it is old, but science is science):
http://www.rx7club.com/single-turbo-...turbos-903210/
According to Geoff at Full Race:
"We have found the twin-scroll systems have higher backpressure at low rpm (which is good for turbo spool-up) and lower backpressure at high rpm (which is good for top-end performance). On the other hand, single-scroll systems have lower backpressure at low rpm (bad for spool-up) and higher backpressure at high rpm (which hurts top-end performance)."
Read more: http://www.superstreetonline.com/how...system-design/
There is an interesting post on the mazda forums, with data from mazda on twin scroll versus single (it is old, but science is science):
http://www.rx7club.com/single-turbo-...turbos-903210/
According to Geoff at Full Race:
"We have found the twin-scroll systems have higher backpressure at low rpm (which is good for turbo spool-up) and lower backpressure at high rpm (which is good for top-end performance). On the other hand, single-scroll systems have lower backpressure at low rpm (bad for spool-up) and higher backpressure at high rpm (which hurts top-end performance)."
Read more: http://www.superstreetonline.com/how...system-design/
Last edited by Jaraxle; Oct 13, 2014 at 05:22 PM. Reason: updated links
#7
i won't dispute the advantages of a twin scroll set-up but i've yet to come across anything short of maybe a T4 manifold for the EVO 8/9 that is designed for a twin scroll housing..
i couldn't get to the content at those URLs either, i think one might be restricted to members only, and the other 404
on paper the twin scroll set-up always seems to be advantageous but there again in practice the differences have a tendency to be marginal
i couldn't get to the content at those URLs either, i think one might be restricted to members only, and the other 404
on paper the twin scroll set-up always seems to be advantageous but there again in practice the differences have a tendency to be marginal
Last edited by doncarbone; Oct 12, 2014 at 10:37 PM.
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#10
Evolved Member
#13
You really think 550 isn't possible given my build parameters? I could opt for some more 'go-fast' mods?