I was wondering what capabilities the GT2560R has in terms of lower boost (~5-8PSI - 220HP?). HP figures, snappiness, spool up, etc. Also, would an eBay log manifold handicap it if I wanted another tune with max HP of ~270 (~15PSI)? Keep in mind this is the same turbo in the Flyin Miata Stage 1 turbo system for all you FM people out there.

The reason I ask is I own a 2001 NB LS with 200k miles. I just bought it with the intention of boosting it myself within 3 or so months. I will not be buying a kit, as I will be combining eBay parts with legit stuff. Here is a quick rundown of my main parts selection so far (things will probably change a bit).

Bay cast iron LOG T3/T4 Exhaust manifold, GT2560R, eBay intercooler + piping, Innovate MTX-L wideband, Five-O 750cc injectors, MegaSquirt 3 v3 ECU, SuperMiata Sport Clutch Full Face 290lbft, custom stainless downpipe. Street car with minor tracking, a little boost lag doesn't scare me, but I don't want a crazy amount.

The reason I ask the initial question is I'd really like to run low boost through this engine until I see the need for rebuilding. I was going to rebuild right off the bat, but it'd be nice to experience the car for a bit before doing so. Before rebuild I'd like to run ~220hp, after I'd like the ability to switch between ~220-240 HP (~5-12PSI?) and ~275hp (~15PSI) through different boost level tunes. I'd probably be in ~220-240 hp tune 50-60% of the time, through normal traffic and getting to the places I want to go faster. I don't see myself ever going over ~275-300HP as driveline would become a prevalent issue long-term.

I'm really curios as to how this turbo preforms at lower boost. I'd go for the GT2554, but it's a little too limited and I'd like the option for some growing room, especially with new rods after rebuild. I also don't really want to drive at ~270 hp at all times even after the rebuild, so for this turbo to fit me it'd need to be able to run at lower boost pressures while still being fun.

I apologize in advance, my HP/boost levels are probably off. I am also very new to turboing NA engine's so I'm trying to learn.

I've seen a few threads on this topic but I wanna hear more people's takes. Threads for reference:

https://forum.miata.net/vb/showthread.php?t=304991 "GT2560 Very little [lag compared to GT2554], but always some lag. About 60 more hp potentially. Good at 10psi, but really happiest at 12-14psi.

https://www.miataturbo.net/dynos-tim...-272-hp-60479/ GT2560 15 PSI at 272HP

https://www.miataturbo.net/dynos-tim...k-motor-66122/ GT2560 230 HP stock motor at 8-10.5 pounds of boost

https://forum.miata.net/vb/showthrea...T2554R+GT2560R "When running it at lower boost (6psi - 170rwhp) I always wished for a bit more initial torque. Now running at 12psi (210-220rwhp est.)"

https://www.miataturbo.net/diy-turbo...stions-108139/ What manifold to use.

 

The 2560r is a great turbo tons of people have used them me included. It's a quick spooling turbo lag won't be an issue with it at all. It can run low boost 5-6psi just fine and can go all the way up to 300ish whp. I made 296whp on mine with a FM log manifold, 2.5" DP etc. You could run this turbo at 10-12psi on the stock motor and probably make 210-230whp with a good tune. You'll want to keep tq below 220ftlb or so because the OEM rods aren't the thickest.

If you can avoid that manifold I would. The newest FM design is good and the kraken stuff is very good which is what I run. The newer manifold designs are more efficient and you'll make the power easier than that old log style eBay manifold. If you can't afford the better manifolds that eBay one works but I would save up for the better turbo manifold designs I mentioned.

 

Damn, at what boost?

 

From his bio, looks like 18psi

 

There were quite a few people pushing a 2560 to near 300whp back in the day, mostly because of e85. It's a great turbo for a stock block since it doesn't boost creep like the gen2's do.

I'd skip that manifold as well, the kraken stuff is super affordable for what it is. The log manifold you linked will work it's just nowhere near as efficient as the newer cast stuff like Andy mentioned.

 

I will point out that a T3/T4 manifold isn't going to fit a 2560. Unless there's something I'm missing, it's a different sized flange.

I had a similar cast iron manifold from an old FM kit with a 2560. Personally I don't think the manifold was a restriction at ~220 WHP.

 

He lists the GT3271 @ 18psi getting him to 294rwhp. 296rwhp out of a 2560 with FM's log and a 2.5" exhaust is more difficult.

I got to 27x rwhp on a dynojet with my 2560 & '94 1.8 @ 14psi. This was with ancient RC440cc injectors and 93 pump gas. Paul was able to get 307rwhp dynojet IIRC, with a '99 1.8 and BEGI's intake manifold, also at 14psi. I think he went to 17psi and only made 311 with silly IAT. These all with my exhaust manifolds and 3" exhaust.

I can't seem to find the data now, but at one point I was making direct replacement tubular manifolds for the FM/BEGI exhaust manifolds. A customer did a back to back comparison...those FM manifolds of that era did not perform well.

+1 on the Kragen parts, that's a no brainer.

 

The 3271 was way back in the day on a semi built BP05. I was running a OEM 1.6 ECU with a fpr, bipes ACU ( to control timing), and some I wanna say 330cc injectors off god knows what. It was a mustang dyno it made 294/270 something tq can't remember. It did run a 12.2 @118mph 1/4 so it had the power even on a OEM ECU.

The 2560r was the old school FM log and their 2.5" dp and the divided wg turbine outlet they used to sell. I was not running straight 93 but a mix of vp octanium which I found gave me the ability to run 3* more ign advance. I was running it at 19psi and it would fall off to 17 by 7200rpm. So that was the best run I could do that day. I even took the air filter off and I picked up 1hp lol. That turbo was completely maxed out but I have a feeling if it was on my kraken low mount manifold and 3" dp it could have done 300. I ended up going GTX gen2 after that and never tried for 300 with it. Great turbo though maybe just as fun as a 2860/2867 gen2. Somehow the 2650 really works on a BP engine.

Yea the old FM log was not good in that it sent #1 and #4 cylinders firing right into each other. The engine note out the exhaust with this manifold was deep kinda like a DSM or something, with the kraken low mount it sounds like a different engine sounds more naturally aspirated if that makes sense a higher pitched exhaust note. I think it's just due to the close to eq runner lengths and the fact the cylinders arent firing directly at each other in the manifold

 

Yes you are right a T3 flange won't work with a T2 flange haha. I don't think at 220whp that manifold is a restriction either, however if you put a better manifold on it that car will pick up +20whp just from the better design better runner lengths etc. I went from a FM log with a 2860gen2 I made 373whp/351ftlb on the dyno. Then I switched to a kraken low mount with 3" dp and it made 401whp/371ftlb. So you can make power with a FM manifold but you'll make more without it. It's not so much a restriction as much as it's just not a great flowing manifold based on it's design.

The 401whp was on virtual dyno. But the day I made 373 on the dynojet VD said I made 370. So it was very close and repeatable...so I used VD on the same stretch of road every time etc. Either way the kraken stuff was head and shoulders above what the FM stuff was back before they redesigned their manifold