Hello there! I'm Gerben and I am a new member to this forum, and I have some questions about turbochargers for a 1.6L.
(Oh god not another newb that's going on about his 1.6L )
I plan on turbocharging in the future, and this would be my setup: Stock '91 1.6L engine 117k miles. Bottom mount absurdflow style manifold, 3’’ DP and exhaust, FMIC.
The power I'm looking for is around 220-230RWTQ for daily driving and autoX equivalents.

I have been looking at a selection of Garrett turbochargers.
- GT2554R
- GT2560R
- GT2860R (310HP model)
When doing this I also got very interested in the T3 50 Trim Chinacharger.

I have made calculations for all 4 of these turbochargers for the (theoretical) maximum power they can output on a 1.6L and these are my results.
If you guys could look at it and share your criticism it will be highly appreciated. I am guessing my calculations are lower then what is actually possible in the real world.
But that's because I estimated a lot of things. The info is based on these turbo's:

Garrett GT2554R:
Compressor Wheel
0.80 A/R Cold Side
Inducer: 42.1 mm
Exducer: 54.3 mm
Trim: 60
Turbine Wheel
0.64 A/R Hot Side
Inducer: 53 mm
Exducer: 41.7 mm
Trim: 62

Garrett GT2560R:
Compressor Wheel
0.60 A/R Cold Side
Inducer: 46.5 mm
Exducer: 60.1 mm
Trim: 60
Turbine Wheel
0.64 A/R Hot Side
Inducer: 53 mm
Exducer: 41.7 mm
Trim: 62

Garrett GT2860R:
Compressor Wheel
0.42 A/R Cold Side
Inducer: 44.6 mm
Exducer: 60.1 mm
Trim: 55
Turbine Wheel
0.64 A/R Hot Side
Inducer: 53.9 mm
Exducer: 42.4 mm
Trim: 62

T3 50 Trim Chinacharger:
Compressor Wheel
0.42 A/R Cold Side
Inducer: 42.5 mm
Exducer: 60 mm
Trim: 50.17
Turbine Wheel
0.48 A/R Hot Side
Inducer: 64 mm
Exducer: 46 mm
Trim: 51.66

Calculations and plotted compressor maps.






The GT2554R will probably be fully spooled @ ~3750 RPM
The GT2560R will probably be fully spooled @ ~4000 RPM
The GT2860R would most likely look a lot like the GT2560R with spooling.
The T3 50 Trim could be fully spooled @ ~3750 RPM

So with that spool data I can conclude that the plotted points for either 3000 and 4000 RPM may be off by a bit in the real world situation, especially the 3000RPM ones.

Please may I have your verdicts and let me know what I got right, or that I'm totally mental with my derp calculations.

Regards, Gerben.

 

If you want Spool Data, there is a very convenient "I want your spool data" thread right above your current thread.
And just because I feel generous today, here's the link https://www.miataturbo.net/diy-turbo...ol-data-26641/

 

Thank you for the notice, although I've been through that thread a couple of times already which was really helpful.
And to be very honest I still think spool-up is very hard to predict because there are so many variables.

Regards

 

2560R

 

+1 on 2560r.

I'm running it and it spools much faster and sooner than the 2860r I had on the 02 miata.

 

You won't make your power goal on a 2554R, and the 2560R won't be nearly as nice to drive on a 1.6L. I would go with the 2560R. You really want a 1.8L.

 

Could you explain why, or do you use it yourself?

Yeah but there are multiple versions of the 2860, this one has the smallest A/R and different turbine wheel IIRC. This compressor maxes out at 31lb/ft.

That's why I got so interested in the 2860, it looks to be between the 2554 and the 2560. Also turbine (and spool) wise it looks a lot like the 2560. (Theoretically it should spool just a tiny bit faster, or just as fast.)

Regards

 

Was the 1.8 ever available in Euro-land? Were there any other EUDM cars with BP engines?

 

UK market had the BP since 94. BP's where also available in many other cars across the Euro market since the early 90's. B6's where still available in miatas as a lesser 1.6i model through the NB generation.

 

You want the 2560....



*has 2860

 

Yes, just as Psyber said right here V

So you have the above mentioned 2860? With the .64 turbine A/R and the 31ft/lb comp wheel? What is your setup and how does it perform on your setup if I may ask?

 

You REALLY want the EFR 6258. ONLY if that's not an option you want the 2560R. I have note heard of any 2860R spooling well on a stock NA6, but I haven't heard everything, so there may be other data out there. Also the 2860 is oversized for your power goals.
And I'm personally running a predecessor to the 2560R (Old T28 with ball bearings) and love it. But not as much as I would love the EFR 6258.

 

first and foremost you want a 1.8
let's get the obvious mentioned first

then you want to consider proper turbo setups.
is 1.6 mandated in your area or is this your own choice? if so, why

 

IMO... Having a 1.8L vehicle allows for quicker spool, displacing more air out of the cylinder. Having the smaller turbine (2560) size allows you to have much more low end torque at an earlier time. You just don't get that with a gt2860 in any shape or form. A 1.6L in theory would have to be displacing a lot more air to get the GT2860 to spool. (at all...)

This image tells all. You're hitting peak tq earlier in the rpms and allowing yourself to pull at an earlier time. Notice how both turbos fall basically the same in tq and have similar hp numbers.

The sagging dip in red is what I experience every day daily driving a 1.8L, it's not enjoyable unless I'm at higher rpms on the highway.

I want my boost and I want it now.


A gt2560 swap is in my near future since I don't have the money for a full EFR setup

 

I get the feeling that you like the 2860 based on your compressor map calculations. Let me crush your dreams for you.

All the numbers in your estimated calculations are 100% BS. Not a single one of the plotted charts makes a lick of sense to anyone with real-world experience running those turbos on these engines. All your peak boost numbers are way off, and the notion that a 2860 will spool the same as a 2560 is just flat wrong. In the real world, the 2860 will spool slower and make a tiny bit more power, and since it's on a 1.6L, it will respond much slower.

Have I mentioned you should not turbo your 1.6L and should instead swap a 1.8L in before pursuing this project?

 

Whenever I hear someone wanting to build their 1.6, I imagine a person who came from a Honda. This is not a Honda 1.6. A b16. And our clunky miata engines are worlds apart. In 1995 it seems like Honda was looking into F1 racing, while Mazda was dabbling in rototillers and other garden equipment.

 

I would like an EFR, if the budget allowed it.

I don't need a 1.8, it would be easier (power wise and spool wise) if I did have a 1.8.
I'm not trying to break any records here. I just want to turbo my 1.6.
The downsides to having a 1.8 miata here: more road tax, higher insurance. To combat that I could swap in a 1.8 but then I will need to have my car get checked and approved by the government, which is a bit of a hassle to do sometimes.

Yeah, I know what you mean with the bigger turbo. And the reason they both fall on their face in top end is because of the bad VE in the miata engines right?

No I don't like the 2860 because of the calculations I did. I know those plotted points on the maps are stupid and are purely theoretical.
For a real world situation I would have to plot points on the same P/R along the rev range am I right?

First of all, I am not a Honda guy, and I know these engines are nothing like honda engines. Thanks for the notice though.

Regards

 

How would they know whether you swapped in a 1.8 or not? You're adding a turbo to the car and you're worried about whether or not they figure out it's a larger displacement motor?

Worst case, why not find a b8 motor, same block as a 1.6 but with larger bore and stroke. not sure if the flanges are the same.

 

They both fall flat in a similar way due to the compressor. No one could of told you better than Sav the outcome of the two. VE would be better described as the 1.6L vs 1.8L imo, more suck and blow (displacement)

Focus on the tq gains. Demonstrated below as... For the same RPM, you exponentially increase your tq output for the same given rpm. The 2560 is spool happy vs the spud, creating a better turbo experience.





IMO, biggest example...

Would you rather have 118tq or 127tq? 140tq or 173tq...

The spud is a dud, if you still plan on running it...

 

the 1.6L is the real dud.