My buddy's 2l miata motor makes 8psi at like 3600 with a boostlogic manifold. I don't see how it will spin up faster, but they know more than I do. I have the same hot-side, smaller cold-side, and I'm making 11psi at 3500rpm with the absurd manifold.

What about the tune? Are you at MBT in the "boost building" cells? What AFR's?

As for the tune, that is handled by Danzio performance. I dont have an answer for you.
I can say he has one hell of a brag book. He used to tune all of the falken cars and still does their rally cars. he still does the Tanaka 600+ftlbs Corvette.
So I trust his tunes. he tunes off of A/R.

Hustler, what is your max boost? Do you think you could hit 20psi by 4k? What turbo do you have again?
What turbo does your buddy have??

Thanks man

If you can't afford slower spool, can you afford headwork/better exhaust/better exhaust manifold? Go BB and water, get a good turbo a bit larger and let the rest of the engine help it spool.

I'd like to see a compressor map. Remember, 20 psi manifold, especially if your intercooler or TB is restrictive, is more than 20 psi turbine outlet. And if the air cleaner isn't up to snuff, you're even further over on the map.

Overspinning it is my best guess. A close second would be getting an oil filter on the turbo oil feed. My friend lost a turbo on his diesel from a little nothing in his oil.

Either that or they are just plain not assembled right. Single bearing turbos are somewhat susceptible to surge.

I have head work- cleaned up, smooth castings, 1mm oversized valves
I have 3" dp and 3" piping with no muffler
BEGI Series 5 manifold.

What about intake manifold and throttle body?

When it was running, did you happen to ever hook boost gauges up both pre and post throttle body? Would be interesting to see what the inefficiencies are.

I've never put more than 18psi through it. Its overboosted to 18psi at 4200rpm or so. I think with the smaller turbine housings, you could probably do it.
gt2860rs w/.86AR turbine housing w/tial wastegate
gt2871 w/ .63AR turbine housing w/tial wastegate

Why don't you call Garrett and tell them what you want? It sounds to me like you want a rally-car style turbo sizing.

Do you know what HP you're making, Hustler? Seems like a slow spool. Open exhaust I assume?

I don't think its slow to spool.
http://i34.tinypic.com/2hcnxbd.png
Due to my drama on the dyno, I still don't have a dyno chart for the forum. My boost gauge died, I went out of town, and now I'm sick...hopefully I'll get on there next weekend to get a final pull with my car and tune another friend's car.
Not open, just 3" exhaust. 12psi at 3400rpm was roughly 220wtq on a mustang, or 245wtq on a dynojet (and too fat in that log). Torque peaks at 4400, but I still need to get it back on the dyno and finish it up with a couple pulls because its basically tuned.

I've driven a well-tuned 1994 W/gt2554 and was not impressed. Its all about perception; mine was faster at every rpm regardless of when I hit target boost. The noise, butt dyno, and boost gauge may not say it, but the dyno doesn't lie.

I did not take those measurements. My throttle body is slightly worked bringing down any cast marks and opene up as much as possible with the stock flapper still sealing.

The intake manifold is modded like Pauls. It may be hurting my spool a bit, but HP carries nicely.

I am at 200ftlbs at 3600rpm.. kinda sucks..
A bit before 4600 I have 310ftlbs. Its a serious jump LOL

Huslter, I do basically want a rally type set up. Need spool, response and power. I am fine with what I have now. It just keeps shitting out..

After talking with FULL RACE and sending them my dyno and compressor maps, they feel there may be a 2871 that will rock..

We will see..

Thanks everyone for your input..

I think a 2871 is not going to do what you want. Look at Savington's set up, it basically delivers power like my car.

With a rally-car style turbo you're not going to make much power, but you'll make a ton of torque down low. You want something that is not "off-the-shelf" and should call someone at Garrett. i know one guy with an old Gallant who rallies the car has a custom turbo from Majestic with tiny housings and "stage-5 compressor and turbine wheels". It makes gobs and gobs of torque at 3500rpm, then no hp after that but it works for rally-x.


I'm really interested to see what you end up with.

I understand what you mean.

My current Dyno plot is just fine. I just cant have it come on any later than that.

The 2860rs seems like it may be spinning a bit too fast..

Abe, never replied to you.

TB and intercooler should be fine. Air cleaner should be ok.

I have the oil filter in the turbo..

I believe assembly and single bearing = not tough enough for me ;)