Miata Turbo Forum - Boost cars, acquire cats.

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-   DIY Turbo Discussion (https://www.miataturbo.net/diy-turbo-discussion-14/)
-   -   the hustler effect. smaller A/R on bigger turbo = better spool. (https://www.miataturbo.net/diy-turbo-discussion-14/hustler-effect-smaller-r-bigger-turbo-%3D-better-spool-38290/)

fmowry 08-22-2009 08:02 PM

There are plenty of Suby guys running 3071 and 3076s with .64 A/R. You're giving up a bit of top end, but not anything a sane responsible person will see on the street. It's a worthy tradeoff unless you get a hardon posting dyno graphs all day.

Quite a few overlays between the two over on NASIOC that show spool differences and top end.

Frank

hustler 08-22-2009 08:27 PM


Originally Posted by y8s (Post 445301)
you of all people should know how important it is to question the current dogma. that's what I'm doing.



you mean you should have chosen the 2871 .86 at first instead of trying the 2860 .64 for a street car and hoping for better spool with the latter?

I'd love to compare them but I don't really want to spend another $500.

SKMetalworks 08-22-2009 09:12 PM

I think anything over 300 whp on a track is worthless unless your running wide ass tires. Atleast in a miata...:loser:

y8s 08-22-2009 11:38 PM

I might be willing to swap housings if someone had the standard .86, but it's kinda gotta have the wastegate welded shut.

incidentally, what's Pauls 2560 A/R?

neogenesis2004 08-23-2009 12:29 AM

WG doesnt need to be welded shut Matt. You can just tie it shut with some wire.

magnamx-5 08-23-2009 12:33 AM

hell with no boost signal the WG wouldnt open anyway just swap and run the shit y8's

TurboTim 08-23-2009 08:08 AM

Remember the "GT2871R" also comes in 3 different compressor trims.


Originally Posted by hustler (Post 445405)
I'd love to compare them but I don't really want to spend another $500.

Anyone with one of my manifolds gets my price on TiAL stuff. At least for the foreseeable future. ;) I did order a seperate .64 v-band turbine as part of the buy in.

EDIT: I really mean you pay retail/lowest allowable price and pay less for the manifold/downpipe...yeah.


Originally Posted by y8s (Post 445446)
I might be willing to swap housings if someone had the standard .86, but it's kinda gotta have the wastegate welded shut.

incidentally, what's Pauls 2560 A/R?

Paul's 2560 is the standard .64, I think the only way the smaller gt25 turbine comes in.

TurboTim 08-23-2009 08:19 AM


Originally Posted by gospeed81 (Post 445106)
Links to dyno sheet?

Sorry, I looked.

I can't find it anywhere.

hustler 08-23-2009 07:20 PM


Originally Posted by sbkcocker499 (Post 445412)
I think anything over 300 whp on a track is worthless unless your running wide ass tires. Atleast in a miata...:loser:

Wrong

rharris19 08-23-2009 07:32 PM


Originally Posted by y8s (Post 445301)
you mean you should have chosen the 2871 .86 at first instead of trying the 2860 .64 for a street car and hoping for better spool with the latter?

What I mean is that since this will be prodominately a track car, I should have gone with the .86 2871. If this was a street car, then I think the .64 2860 would be perfect.

rharris19 08-23-2009 07:33 PM


Originally Posted by TurboTim (Post 445555)
I can't find it anywhere.

Lemme see if I can find it in my email.

ZX-Tex 08-23-2009 08:27 PM


Originally Posted by rharris19 (Post 445692)
What I mean is that since this will be prodominately a track car, I should have gone with the .86 2871. If this was a street car, then I think the .64 2860 would be perfect.

Or get a bit of the best of both, with a 0.64 a/r 2871 :bigtu:

rharris19 08-24-2009 01:10 PM

http://i27.tinypic.com/w8klex.jpg

hustler 08-24-2009 01:58 PM


Originally Posted by ZX-Tex (Post 445705)
Or get a bit of the best of both, with a 0.64 a/r 2871 :bigtu:

judging from the dyno bleow, you and most others in this thread are wrong. Not shit talking...it just looks like the big turbine housing is prevailing. I lucked out.

ZX-Tex 08-24-2009 02:10 PM

At constant boost maybe, but what about flattening the torque curve by raising boost at higher levels? The bigger compressor wheel will keep the discharge air temperatures down (efficiency) and the added boost will help offset the higher flow turbine losses at higher RPMs. I plan on trying this myself. 225 ft*lb or so carried to as high an RPM as possible should be great. 225 ft*lbs @ 7000 RPM = 300 bhp. 225 ft*lbs @ 8000 RPM = 342 BHP (about 300 RWHP). Should be able to do this with a built motor from what I have seen.

There is no right answer here, just a matter of choosing one's compromise.

hustler 08-24-2009 02:33 PM


Originally Posted by ZX-Tex (Post 445946)
At constant boost maybe, but what about flattening the torque curve by raising boost at higher levels? The bigger compressor wheel will keep the discharge air temperatures down (efficiency) and the added boost will help offset the higher flow turbine losses at higher RPMs. I plan on trying this myself. 225 ft*lb or so carried to as high an RPM as possible should be great. 225 ft*lbs @ 7000 RPM = 300 bhp. 225 ft*lbs @ 8000 RPM = 342 BHP (about 300 RWHP). Should be able to do this with a built motor from what I have seen.

There is no right answer here, just a matter of choosing one's compromise.

I'm no engineer, but it looks like the wrong answer is the intake plenum because a few of us are on a wall.

ZX-Tex 08-24-2009 03:14 PM

I'm working on the intake right now; I'm removing VICS and opening up the plenum. The top half is done, and I am working on the bottom half now. Not as good as a full-up custom intake with a larger throttle but cheaper and easier.

samnavy 08-24-2009 08:16 PM

^I'm in for data on this. I don't think anybody has had a direct before/after dyno plot for gutting the 99-00 manifold.

thesnowboarder 08-24-2009 08:42 PM


Originally Posted by samnavy (Post 446070)
^I'm in for data on this. I don't think anybody has had a direct before/after dyno plot for gutting the 99-00 manifold.

I will most likely be gutting my 99 intake manifold after i hit the dyno for shits and giggles. Will create a thread if i do.

rharris19 08-24-2009 08:43 PM

We may soon. I was going to do the same thing ZX-Tex is doing, but if he is doing it soon then I will wait.

How long do you think it will take? I was going to try to do it within the next few weeks.


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